1985
ENGINES OF CREATION
by K. Eric Drexler
foreword by Marvin Minsky
(C) Copyright 1986, K. Eric Drexler
Used with permission of K. Eric Drexler
Electronically Enhanced Text (c) Copyright 1996, World Library(R)
AUTHOR'S INTRODUCTION TO THE ELECTRONIC EDITION OF
ENGINES OF CREATION
-
I'm pleased that World Library, Inc. has chosen to include Engines
of Creation in their Library of the Future Series Second Edition.
Engines of Creation is the first book on the subject of
nanotechnology, that is, thorough control of the structure of matter
at the molecular level. One result of this anticipated capability is
molecular manufacturing, which will enable products to be made
cheaply, cleanly and reliably. We can expect far-reaching consequences
for medicine, the economy, the military, and the environment.
I completed Engines of Creation in 1985, and there has been much
progress in this new field since then. We have passed several
milestones (for example, successful engineering of devices made of
protein), and undertaken research projects (the Aono Atomcraft Project
in Japan, for example). The respected scientific journal Nature (7 Feb
1991) has stated "Nanotechnology seems destined to become Japan's next
priority target for industrial research." Together with new
proposals for implementation, these facts paint a picture of major
developments just around the corner rather than in the indefinite
future.
Engines of Creation suggests ways to reduce problems resulting
from the new technologies. One of these ways is through the
development of Hypertext publishing services. These services will
store much of the world's knowledge electronically, easily accessed
on-line. New ideas will constantly be introduced and debated while
being efficiently compared to previously known concepts.
The Library of the Future Series is a major step towards gathering
much of the world's knowledge in an electronic format. Its ability
to search and retrieve topics or ideas for reference and study heralds
a new era.
The Afterword of this book tells readers how to get updated
information on the progress of nanotechnology.
-
K. Eric Drexler
May 1991
FOREWORD
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K. ERIC DREXLER'S Engines of Creation is an enormously original book
about the consequences of new technologies. It is ambitious and
imaginative and, best of all, the thinking is technically sound.
But how can anyone predict where science and technology will take
us? Although many scientists and technologists have tried to do
this, isn't it curious that the most successful attempts were those of
science fiction writers like Jules Verne and H. G. Wells, Frederik
Pohl, Robert Heinlein, Isaac Asimov, and Arthur C. Clarke? Granted,
some of those writers knew a great deal about the science of their
times. But perhaps the strongest source of their success was that they
were equally concerned with the pressures and choices they imagined
emerging from their societies. For, as Clarke himself has
emphasized, it is virtually impossible to predict the details of
future technologies for more than perhaps half a century ahead. For
one thing, it is virtually impossible to predict in detail which
alternatives will become technically feasible over any longer interval
of time. Why? Simply because if one could see ahead that clearly,
one could probably accomplish those things in much less time- given
the will to do so. A second problem is that it is equally hard to
guess the character of the social changes likely to intervene. Given
such uncertainty, looking ahead is like building a very tall and
slender tower of reasoning. And we all know that such constructions
are untrustworthy.
How could one build a sounder case? First, the foundations must be
very firm- and Drexler has built on the soundest areas of
present-day technical knowledge. Next, one must support each important
conclusion step in several different ways, before one starts the next.
This is because no single reason can be robust enough to stand
before so many unknowns. Accordingly, Drexler gives us multiple
supports for each important argument. Finally, it is never entirely
safe to trust one's own judgments in such matters, since all of us
have wishes and fears which bias how we think- without our knowing it.
But, unlike most iconoclasts, Drexler has for many years
courageously and openly exposed these ideas to both the most
conservative skeptics and the most wishful-thinking dreamers among
serious scientific communities like the one around MIT. He has
always listened carefully to what the others said, and sometimes
changed his views accordingly.
Engines of Creation begins with the insight that what we can do
depends on what we can build. This leads to a careful analysis of
possible ways to stack atoms. Then Drexler asks, "What could we
build with those atom-stacking mechanisms?" For one thing, we could
manufacture assembly machines much smaller even than living cells, and
make materials stronger and lighter than any available today. Hence,
better spacecraft. Hence, tiny devices that can travel along
capillaries to enter and repair living cells. Hence, the ability to
heal disease, reverse the ravages of age, or make our bodies
speedier or stronger than before. And we could make machines down to
the size of viruses, machines that would work at speeds which none
of us can yet appreciate. And then, once we learned how to do it, we
would have the option of assembling these myriads of tiny parts into
intelligent machines, perhaps based on the use of trillions of
nanoscopic parallel-processing devices which make descriptions,
compare them to recorded patterns, and then exploit the memories of
all their previous experiments. Thus those new technologies could
change not merely the materials and means we use to shape our physical
environment, but also the activities we would then be able to pursue
inside whichever kind of world we make.
Now, if we return to Arthur C. Clarke's problem of predicting more
than fifty years ahead, we see that the topics Drexler treats make
this seem almost moot. For once that atom-stacking process starts,
then "only fifty years" could bring more change than all that had come
about since near-medieval times. For, it seems to me, in spite of
all we hear about modern technological revolutions, they really
haven't made such large differences in our lives over the past half
century. Did television really change our world? Surely less than
radio did, and even less than the telephone did. What about airplanes?
They merely reduced travel times from days to hours- whereas the
railroad and automobile had already made a larger change by shortening
those travel times from weeks to days! But Engines of Creation sets us
on the threshold of genuinely significant changes; nanotechnology
could have more effect on our material existence than those last two
great inventions in that domain- the replacement of sticks and
stones by metals and cements and the harnessing of electricity.
Similarly, we can compare the possible effects of artificial
intelligence on how we think- and on how we might come to think
about ourselves- with only two earlier inventions: those of language
and of writing.
We'll soon have to face some of these prospects and options. How
should we proceed to deal with them? Engines of Creation explains
how these new alternatives could be directed toward many of our most
vital human concerns: toward wealth or poverty, health or sickness,
peace or war. And Drexler offers no mere neutral catalog of
possibilities, but a multitude of ideas and proposals for how one
might start to evaluate them. Engines of Creation is the best
attempt so far to prepare us to think of what we might become,
should we persist in making new technologies.
-
MARVIN MINSKY
Donner Professor of Science
Massachusetts Institute of Technology
ACKNOWLEDGMENTS
-
THE IDEAS IN THIS BOOK have been shaped by many minds. All authors
bear an incalculable debt to earlier writers and thinkers, and the
Notes and References section provides a partial acknowledgment of my
debt. But other people have had a more immediate influence by
reading and criticizing all or part of the several papers, articles,
and draft manuscripts ancestral to the present version of this book.
Their contributions have ranged from brief letters to extensive,
detailed criticisms, suggestions, and revisions; they deserve much
of the credit for the evolution of the manuscript toward its present
form and content. I do, however, claim all blame for its remaining
failings.
Accordingly, I would like to thank Dale Amon, David Anderson,
Alice Barkan, James Bennett, David Blackwell, Kenneth Boulding, Joe
Boyle, Stephen Bridge, James Cataldo, Fred and Linda Chamberlain, Hugh
Daniel, Douglas Denholm, Peter Diamandis, Thomas Donaldson, Allan
Drexler, Hazel Drexler, Arthur Dula, Freeman Dyson, Erika Erdmann,
Robert Ettinger, Mike Federowicz, Carl Feynman, David Forrest,
Christopher Fry, Andy, Donna, Mark, and Scott Gassmann, Hazel and
Ralph Gassmann, Agnes Gregory, Roger Gregory, David Hannah, Keith
Henson, Eric Hill, Hugh Hixon, Miriam Hopkins, Joe Hopkins, Barbara
Marx Hubbard, Scott A. Jones, Arthur Kantrowitz, Manfred Karnovsky,
Pamela Keller, Tom and Mara Lansing, Jerome Lettvin, Elaine Lewis,
David Lindbergh, Spencer Love, Robert and Susan Lovell, Steve Lubar,
Arel Lucas, John Mann, Jeff MacGillivray, Bruce Mackenzie, Marvin
Minsky, Chip Morningstar, Philip Morrison, Kevin Nelson, Hugh O'Neill,
Gayle Pergamit, Gordon and Mary Peterson, Norma and Amy Peterson,
Naomi Reynolds, Carol Rosin, Phil Salin, Conrad Schneiker, Alice
Dawn Schuster, Rosemary Simpson, Leif Smith, Ray Sperber, David Sykes,
Paul Trachtman, Kevin Ulmer, Patricia Wagner, Christopher Walsh, Steve
Witham, David Woodcock, and Elisa Wynn. Since this list was compiled
from imperfect files and heaps of marked-up manuscripts, I apologize
to those I may have omitted. Further thanks are due to the members
of many audiences, at MIT and elsewhere, for asking questions that
helped me refine these ideas and their presentation.
For their help and encouragement, I would also like to thank my
agent, Norman Kurz, and my editors, James Raimes, Dave Barbor, and
Patrick Filley. Finally, for contributions of special quality and
magnitude throughout this effort, I would like to thank Mark S. Miller
and, most of all, Christine Peterson. Without her help, it would not
have been possible at all.
PART ONE
The Foundations of Foresight
-
1
Engines of Construction*
-
Protein engineering... represents*(2) the first major step toward
a more general capability for molecular engineering which would
allow us to structure matter atom by atom.
-KEVIN ULMER
Director of Exploratory Research
Genex Corporation
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COAL AND DIAMONDS, sand and computer chips, cancer and healthy
tissue: throughout history, variations in the arrangement of atoms
have distinguished the cheap from the cherished, the diseased from the
healthy. Arranged one way, atoms make up soil, air, and water;
arranged another, they make up ripe strawberries. Arranged one way,
they make up homes and fresh air; arranged another, they make up ash
and smoke.
Our ability to arrange atoms lies at the foundation of technology.
We have come far in our atom arranging, from chipping flint for
arrowheads to machining aluminum for spaceships. We take pride in
our technology, with our lifesaving drugs and desktop computers. Yet
our spacecraft are still crude, our computers are still stupid, and
the molecules in our tissues still slide into disorder, first
destroying health, then life itself. For all our advances in arranging
atoms, we still use primitive methods. With our present technology, we
are still forced to handle atoms in unruly herds.
But the laws of nature leave plenty of room for progress, and the
pressures of world competition are even now pushing us forward. For
better or for worse, the greatest technological breakthrough in
history is still to come.
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TWO STYLES OF TECHNOLOGY
-
Our modern technology builds on an ancient tradition. Thirty
thousand years ago, chipping flint was the high technology of the day.
Our ancestors grasped stones containing trillions of trillions of
atoms and removed chips containing billions of trillions of atoms to
make their axheads; they made fine work with skills difficult to
imitate today. They also made patterns on cave walls in France with
sprayed paint, using their hands as stencils. Later they made pots
by baking clay, then bronze by cooking rocks. They shaped bronze by
pounding it. They made iron, then steel, and shaped it by heating,
pounding, and removing chips.
We now cook up pure ceramics and stronger steels, but we still shape
them by pounding, chipping, and so forth. We cook up pure silicon, saw
it into slices, and make patterns on its surface using tiny stencils
and sprays of light. We call the products "chips" and we consider them
exquisitely small, at least in comparison to axheads.
Our microelectronic technology has managed to stuff machines as
powerful as the room-sized computers of the early 1950s onto a few
silicon chips in a pocket-sized computer. Engineers are now making
ever smaller devices, slinging herds of atoms at a crystal surface
to build up wires and components one tenth the width of a fine hair.
These microcircuits may be small by the standards of flint chippers,
but each transistor still holds trillions of atoms, and so-called
"microcomputers" are still visible to the naked eye. By the
standards of a newer, more powerful technology they will seem
gargantuan.
The ancient style of technology that led from flint chips to silicon
chips handles atoms and molecules in bulk; call it bulk technology.
The new technology will handle individual atoms and molecules with
control and precision; call it molecular technology. It will change
our world in more ways than we can imagine.
Microcircuits have parts measured in micrometers- that is, in
millionths of a meter- but molecules are measured in nanometers (a
thousand times smaller). We can use the terms "nanotechnology" and
"molecular technology" interchangeably to describe the new style of
technology. The engineers of the new technology will build both
nanocircuits and nanomachines.
-
MOLECULAR TECHNOLOGY TODAY
-
One dictionary*(3) definition of a machine is "any system, usually
of rigid bodies, formed and connected to alter, transmit, and direct
applied forces in a predetermined manner to accomplish a specific
objective, such as the performance of useful work." Molecular machines
fit this definition quite well.
To imagine these machines, one must first picture molecules. We
can picture atoms as beads and molecules as clumps of beads, like a
child's beads linked by snaps. In fact, chemists do sometimes
visualize molecules by building models from plastic beads (some of
which link in several directions, like the hubs in a Tinkertoy set).
Atoms are rounded like beads, and although molecular bonds are not
snaps, our picture at least captures the essential notion that bonds
can be broken and reformed.
If an atom were the size of a small marble, a fairly complex
molecule would be the size of your fist. This makes a useful mental
image, but atoms are really about 1/10,000 the size of bacteria, and
bacteria are about 1/10,000 the size of mosquitoes. (An atomic
nucleus, however, is about 1/100,000 the size of the atom itself;
the difference between an atom and its nucleus is the difference
between a fire and a nuclear reaction.)
The things around us act as they do because of the way their
molecules behave. Air holds neither its shape nor its volume because
its molecules move freely, bumping and ricocheting through open space.
Water molecules stick together as they move about, so water holds a
constant volume as it changes shape. Copper holds its shape because
its atoms stick together in regular patterns; we can bend it and
hammer it because its atoms can slip over one another while
remaining bound together. Glass shatters when we hammer it because its
atoms separate before they slip. Rubber consists of networks of kinked
molecules, like a tangle of springs. When stretched and released,
its molecules straighten and then coil again. These simple molecular
patterns make up passive substances. More complex patterns make up the
active nanomachines of living cells.
Biochemists already work with these machines, which are chiefly made
of protein, the main engineering material of living cells. These
molecular machines have relatively few atoms, and so they have lumpy
surfaces, like objects made by gluing together a handful of small
marbles. Also, many pairs of atoms are linked by bonds that can bend
or rotate, and so protein machines are unusually flexible. But like
all machines, they have parts of different shapes and sizes that do
useful work. All machines use clumps of atoms as parts. Protein
machines simply use very small clumps.
Biochemists dream of designing and building such devices, but
there are difficulties to be overcome. Engineers use beams of light to
project patterns onto silicon chips, but chemists must build much more
indirectly than that. When they combine molecules in various
sequences, they have only limited control over how the molecules join.
When biochemists need complex molecular machines, they still have to
borrow them from cells. Nevertheless, advanced molecular machines will
eventually let them build nanocircuits and nanomachines as easily
and directly as engineers now build microcircuits or washing machines.
Then progress will become swift and dramatic.
Genetic engineers are already showing the way. Ordinarily, when
chemists make molecular chains- called "polymers"- they dump molecules
into a vessel where they bump and snap together haphazardly in a
liquid. The resulting chains have varying lengths, and the molecules
are strung together in no particular order.
But in modern gene synthesis machines,*(4) genetic engineers build
more orderly polymers- specific DNA molecules- by combining
molecules in a particular order. These molecules are the nucleotides
of DNA (the letters of the genetic alphabet) and genetic engineers
don't dump them all in together. Instead, they direct the machine to
add different nucleotides in a particular sequence to spell out a
particular message. They first bond one kind of nucleotide to the
chain ends, then wash away the leftover material and add chemicals
to prepare the chain ends to bond the next nucleotide. They grow
chains as they bond on nucleotides, one at a time, in a programmed
sequence. They anchor the very first nucleotide in each chain to a
solid surface to keep the chain from washing away with its chemical
bathwater. In this way, they have a big clumsy machine in a cabinet
assemble specific molecular structures from parts a hundred million
times smaller than itself.
But this blind assembly process accidentally omits nucleotides
from some chains. The likelihood of mistakes grows as chains grow
longer. Like workers discarding bad parts before assembling a car,
genetic engineers reduce errors by discarding bad chains. Then, to
join these short chains into working genes (typically thousands of
nucleotides long), they turn to molecular machines found in bacteria.
These protein machines, called restriction enzymes, "read" certain
DNA sequences as "cut here." They read these genetic patterns by
touch, by sticking to them, and they cut the chain by rearranging a
few atoms. Other enzymes splice pieces together, reading matching
parts as "glue here"- likewise "reading" chains by selective
stickiness and splicing chains by rearranging a few atoms. By using
gene machines to write, and restriction enzymes to cut and paste,
genetic engineers can write and edit whatever DNA messages they
choose.
But by itself, DNA is a fairly worthless molecule. It is neither
strong like Kevlar, nor colorful like a dye, nor active like an
enzyme, yet it has something that industry is prepared to spend
millions of dollars to use: the ability to direct molecular machines
called ribosomes. In cells, molecular machines first transcribe DNA,
copying its information to make RNA "tapes." Then, much as old
numerically controlled machines shape metal based on instructions
stored on tape, ribosomes build proteins based on instructions
stored on RNA strands. And proteins are useful.
Proteins, like DNA, resemble strings of lumpy beads. But unlike DNA,
protein molecules fold up to form small objects able to do things.
Some are enzymes, machines that build up and tear down molecules
(and copy DNA, transcribe it, and build other proteins in the cycle of
life). Other proteins are hormones, binding to yet other proteins to
signal cells to change their behavior. Genetic engineers can produce
these objects cheaply by directing the cheap and efficient molecular
machinery inside living organisms to do the work. Whereas engineers
running a chemical plant must work with vats of reacting chemicals
(which often misarrange atoms and make noxious byproducts),
engineers working with bacteria can make them absorb chemicals,
carefully rearrange the atoms, and store a product or release it
into the fluid around them.
Genetic engineers have now programmed bacteria to make proteins
ranging from human growth hormone to rennin, an enzyme used in
making cheese. The pharmaceutical company Eli Lilly (Indianapolis)
is now marketing Humulin, human insulin molecules made by bacteria.
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EXISTING PROTEIN MACHINES
-
These protein hormones and enzymes selectively stick to other
molecules. An enzyme changes its target's structure, then moves on;
a hormone affects its target's behavior only so long as both remain
stuck together. Enzymes and hormones can be described in mechanical
terms, but their behavior is more often described in chemical terms.
But other proteins serve basic mechanical functions.*(5) Some push
and pull, some act as cords or struts, and parts of some molecules
make excellent bearings. The machinery of muscle, for instance, has
gangs of proteins that reach, grab a "rope" (also made of protein),
pull it, then reach out again for a fresh grip; whenever you move, you
use these machines. Amoebas and human cells move and change shape by
using fibers and rods that act as molecular muscles and bones. A
reversible, variable-speed motor drives bacteria through water by
turning a corkscrew-shaped propeller. If a hobbyist could build tiny
cars around such motors, several billions of billions would fit in a
pocket, and 150-lane freeways could be built through your finest
capillaries.
Simple molecular devices combine to form systems resembling
industrial machines. In the 1950s engineers developed machine tools
that cut metal under the control of a punched paper tape. A century
and a half earlier, Joseph-Marie Jacquard had built a loom that wove
complex patterns under the control of a chain of punched cards. Yet
over three billion years before Jacquard, cells had developed the
machinery of the ribosome. Ribosomes are proof that nanomachines built
of protein and RNA can be programmed to build complex molecules.
Then consider viruses. One kind, the T4 phage, acts like a
spring-loaded syringe and looks like something out of an industrial
parts catalog. It can stick to a bacterium, punch a hole, and inject
viral DNA (yes, even bacteria suffer infections). Like a conqueror
seizing factories to build more tanks, this DNA then directs the
cell's machines to build more viral DNA and syringes. Like all
organisms, these viruses exist because they are fairly stable and
are good at getting copies of themselves made.
Whether in cells or not, nanomachines obey the universal laws of
nature. Ordinary chemical bonds hold their atoms together, and
ordinary chemical reactions (guided by other nanomachines) assemble
them. Protein molecules can even join to form machines without special
help, driven only by thermal agitation and chemical forces. By
mixing viral proteins (and the DNA they serve) in a test tube,
molecular biologists have assembled working T4 viruses. This ability
is surprising: imagine putting automotive parts in a large box,
shaking it, and finding an assembled car when you look inside! Yet the
T4 virus is but one of many self-assembling structures.*(6)
Molecular biologists have taken the machinery of the ribosome apart
into over fifty separate protein and RNA molecules, and then
combined them in test tubes to form working ribosomes again.
To see how this happens, imagine different T4 protein chains
floating around in water. Each kind folds up to form a lump with
distinctive bumps and hollows, covered by distinctive patterns of
oiliness, wetness, and electric charge. Picture them wandering and
tumbling, jostled by the thermal vibrations of the surrounding water
molecules. From time to time two bounce together, then bounce apart.
Sometimes, though, two bounce together and fit, bumps in hollows, with
sticky patches matching; they then pull together and stick. In this
way protein adds to protein to make sections of the virus, and
sections assemble to form the whole.
Protein engineers will not need nanoarms and nanohands to assemble
complex nanomachines. Still, tiny manipulators will be useful and they
will be built. Just as today's engineers build machinery as complex as
player pianos and robot arms from ordinary motors, bearings, and
moving parts, so tomorrow's biochemists will be able to use protein
molecules as motors, bearings, and moving parts to build robot arms
which will themselves be able to handle individual molecules.
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DESIGNING WITH PROTEIN*(7)
-
How far off is such an ability? Steps have been taken, but much work
remains to be done. Biochemists have already mapped the structures
of many proteins. With gene machines to help write DNA tapes, they can
direct cells to build any protein they can design.*(8) But they
still don't know how to design chains that will fold up to make
proteins of the right shape and function. The forces that fold
proteins are weak, and the number of plausible ways a protein might
fold is astronomical, so designing a large protein from scratch
isn't easy.
The forces that stick proteins together to form complex machines are
the same ones that fold the protein chains in the first place. The
differing shapes and kinds of stickiness of amino acids- the lumpy
molecular "beads" forming protein chains- make each protein chain fold
up in a specific way to form an object of a particular shape.
Biochemists have learned rules that suggest how an amino acid chain
might fold, but the rules aren't very firm. Trying to predict how a
chain will fold is like trying to work a jigsaw puzzle, but a puzzle
with no pattern printed on its pieces to show when the fit is correct,
and with pieces that seem to fit together about as well (or as
badly) in many different ways, all but one of them wrong. False starts
could consume many lifetimes, and a correct answer might not even be
recognized. Biochemists using the best computer programs now available
still cannot predict how a long, natural protein chain will actually
fold, and some of them have despaired of designing protein molecules
soon.
Yet most biochemists work as scientists, not as engineers. They work
at predicting how natural proteins will fold, not at designing
proteins that will fold predictably. These tasks may sound
similar,*(9) but they differ greatly: the first is a scientific
challenge, the second is an engineering challenge. Why should
natural proteins fold in a way that scientists will find easy to
predict? All that nature requires is that they in fact fold correctly,
not that they fold in a way obvious to people.
Proteins could be designed from the start with the goal of making
their folding more predictable. Carl Pabo, writing in the journal
Nature,*(10) has suggested a design strategy based on this insight,
and some biochemical engineers have designed and built short chains of
a few dozen pieces*(11) that fold and nestle onto the surfaces of
other molecules as planned. They have designed from scratch a
protein*(12) with properties like those of melittin, a toxin in bee
venom. They have modified existing enzymes, changing their behaviors
in predictable ways.*(13) Our understanding of proteins is growing
daily.
In 1959, according to biologist Garrett Hardin,*(14) some
geneticists called genetic engineering impossible; today, it is an
industry. Biochemistry and computer-aided design are now exploding
fields, and as Frederick Blattner wrote in the journal Science,*(15)
"computer chess programs have already reached the level below the
grand master. Perhaps the solution to the protein-folding problem is
nearer than we think." William Rastetter of Genentech, writing in
Applied Biochemistry and Biotechnology,*(16) asks, "How far off is
de novo enzyme design and synthesis? Ten, fifteen years?" He
answers, "Perhaps not that long."
Forrest Carter of the U.S. Naval Research Laboratory, Ari Aviram and
Philip Seiden of IBM, Kevin Ulmer of Genex Corporation, and other
researchers in university and industrial laboratories around the globe
have already begun theoretical work and experiments aimed at
developing molecular switches, memory devices, and other structures
that could be incorporated into a protein-based computer. The U.S.
Naval Research Laboratory has held two international workshops on
molecular electronic devices,*(17) and a meeting sponsored by the U.S.
National Science Foundation has recommended support for basic
research*(18) aimed at developing molecular computers. Japan has
reportedly begun a multimillion-dollar program aimed at developing
self-assembling molecular motors and computers, and VLSI Research
Inc.,*(19) of San Jose, reports that "It looks like the race to
bio-chips [another term for molecular electronic systems] has
already started. NEC, Hitachi, Toshiba, Matsushita, Fujitsu,
Sanyo-Denki and Sharp have commenced full-scale research efforts on
bio-chips for bio-computers."
Biochemists have other reasons to want to learn the art of protein
design. New enzymes promise to perform dirty, expensive chemical
processes more cheaply and cleanly, and novel proteins will offer a
whole new spectrum of tools to biotechnologists. We are already on the
road to protein engineering, and as Kevin Ulmer notes in the quote
from Science that heads this chapter, this road leads "toward a more
general capability for molecular engineering which would allow us to
structure matter atom by atom."
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SECOND-GENERATION NANOTECHNOLOGY
-
Despite its versatility, protein has shortcomings as an
engineering material. Protein machines quit when dried, freeze when
chilled, and cook when heated. We do not build machines of flesh,
hair, and gelatin; over the centuries, we have learned to use our
hands of flesh and bone to build machines of wood, ceramic, steel, and
plastic. We will do likewise in the future. We will use protein
machines to build nanomachines of tougher stuff than protein.
As nanotechnology moves beyond reliance on proteins, it will grow
more ordinary from an engineer's point of view. Molecules will be
assembled like the components of an erector set, and well-bonded parts
will stay put. Just as ordinary tools can build ordinary machines from
parts, so molecular tools will bond molecules together to make tiny
gears, motors, levers, and casings, and assemble them to make
complex machines.
Parts containing only a few atoms will be lumpy, but engineers can
work with lumpy parts if they have smooth bearings to support them.
Conveniently enough, some bonds between atoms make fine bearings; a
part can be mounted by means of a single chemical bond*(20) that
will let it turn freely and smoothly. Since a bearing can be made
using only two atoms (and since moving parts need have only a few
atoms), nanomachines can indeed have mechanical components of
molecular size.
How will these better machines be built? Over the years, engineers
have used technology to improve technology. They have used metal tools
to shape metal into better tools, and computers to design and
program better computers. They will likewise use protein
nanomachines to build better nanomachines. Enzymes show the way:
they assemble large molecules by "grabbing" small molecules from the
water around them, then holding them together so that a bond forms.
Enzymes assemble DNA, RNA, proteins, fats, hormones, and chlorophyll
in this way- indeed, virtually the whole range of molecules found in
living things.
Biochemical engineers, then, will construct new enzymes to
assemble new patterns of atoms. For example, they might make an
enzyme-like machine which will add carbon atoms to a small spot, layer
on layer. If bonded correctly, the atoms will build up to form a fine,
flexible diamond fiber*(21) having over fifty times as much strength
as the same weight of aluminum. Aerospace companies will line up to
buy such fibers by the ton to make advanced composites. (This shows
one small reason why military competition will drive molecular
technology forward, as it has driven so many fields in the past.)
But the great advance will come when protein machines are able to
make structures more complex than mere fibers. These programmable
protein machines will resemble ribosomes programmed by RNA, or the
older generation of automated machine tools programmed by punched
tapes. They will open a new world of possibilities, letting
engineers escape the limitations of proteins to build rugged,
compact machines with straightforward designs.
Engineered proteins will split and join molecules as enzymes do.
Existing proteins bind a variety of smaller molecules, using them as
chemical tools; newly engineered proteins will use all these tools and
more.
Further, organic chemists have shown that chemical reactions can
produce remarkable results even without nanomachines to guide the
molecules. Chemists have no direct control over the tumbling motions
of molecules in a liquid, and so the molecules are free to react in
any way they can, depending on how they bump together. Yet chemists
nonetheless coax reacting molecules*(22) to form regular structures
such as cubic and dodecahedral molecules, and to form unlikely-seeming
structures such as molecular rings with highly strained bonds.
Molecular machines will have still greater versatility in
bondmaking, because they can use similar molecular motions to make
bonds, but can guide these motions in ways that chemists cannot.
Indeed, because chemists cannot yet direct molecular motions, they
can seldom assemble complex molecules according to specific plans. The
largest molecules they can make with specific, complex patterns are
all linear chains. Chemists form these patterns (as in gene
machines) by adding molecules in sequence, one at a time, to a growing
chain. With only one possible bonding site per chain, they can be sure
to add the next piece in the right place.
But if a rounded, lumpy molecule has (say) a hundred hydrogen
atoms on its surface, how can chemists split off just one particular
atom (the one five up and three across from the bump on the front)
to add something in its place? Stirring simple chemicals together will
seldom do the job, because small molecules can seldom select
specific places to react with a large molecule. But protein machines
will be more choosy.
A flexible, programmable protein machine will grasp a large molecule
(the workpiece) while bringing a small molecule up against it in
just the right place. Like an enzyme, it will then bond the
molecules together. By bonding molecule after molecule to the
workpiece, the machine will assemble a larger and larger structure
while keeping complete control of how its atoms are arranged. This
is the key ability that chemists have lacked.
Like ribosomes, such nanomachines can work under the direction of
molecular tapes. Unlike ribosomes, they will handle a wide variety
of small molecules (not just amino acids) and will join them to the
workpiece anywhere desired, not just to the end of a chain. Protein
machines will thus combine the splitting and joining abilities of
enzymes with the programmability of ribosomes. But whereas ribosomes
can build only the loose folds of a protein, these protein machines
will build small, solid objects of metal, ceramic, or diamond-
invisibly small, but rugged.
Where our fingers of flesh are likely to bruise or burn, we turn
to steel tongs. Where protein machines are likely to crush or
disintegrate, we will turn to nanomachines made of tougher stuff.
-
UNIVERSAL ASSEMBLERS
-
These second-generation nanomachines- built of more than just
proteins- will do all that proteins can do, and more.*(23) In
particular, some will serve as improved devices for assembling
molecular structures. Able to tolerate acid or vacuum, freezing or
baking, depending on design, enzyme-like second-generation machines
will be able to use as "tools" almost any of the reactive molecules
used by chemists- but they will wield them with the precision of
programmed machines. They will be able to bond atoms together in
virtually any stable pattern, adding a few at a time to the surface of
a workpiece until a complex structure is complete. Think of such
nanomachines as assemblers.*(24)
Because assemblers will let us place atoms in almost any
reasonable arrangement (as discussed in the Notes),*(25) they will let
us build almost anything that the laws of nature allow to exist. In
particular, they will let us build almost anything we can design-
including more assemblers. The consequences of this will be
profound, because our crude tools have let us explore only a small
part of the range of possibilities that natural law permits.
Assemblers will open a world of new technologies.
Advances in the technologies of medicine, space, computation, and
production- and warfare- depend on our ability to arrange atoms.
With assemblers, we will be able to remake our world or destroy it. So
at this point it seems wise to step back and look at the prospect as
clearly as we can, so we can be sure that assemblers and
nanotechnology are not a mere futurological mirage.
-
NAILING DOWN CONCLUSIONS
-
In everything I have been describing, I have stuck closely to the
demonstrated facts of chemistry and molecular biology. Still, people
regularly raise certain questions rooted in physics and biology. These
deserve more direct answers.
-Will the uncertainty principle of quantum physics make molecular
machines unworkable?
This principle states (among other things) that particles can't be
pinned down in an exact location for any length of time. It limits
what molecular machines can do, just as it limits what anything else
can do. Nonetheless, calculations show that the uncertainty
principle places few important limits on how well atoms can be held in
place, at least for the purposes outlined here. The uncertainty
principle makes electron positions quite fuzzy, and in fact this
fuzziness determines the very size and structure of atoms. An atom
as a whole, however, has a comparatively definite position set by
its comparatively massive nucleus. If atoms didn't stay put fairly
well, molecules would not exist. One needn't study quantum mechanics
to trust these conclusions, because molecular machines in the cell
demonstrate that molecular machines work.
-Will the molecular vibrations of heat make molecular machines
unworkable or too unreliable for use?
Thermal vibrations will cause greater problems than will the
uncertainty principle, yet here again existing molecular machines
directly demonstrate that molecular machines can work at ordinary
temperatures. Despite thermal vibrations, the DNA-copying machinery in
some cells*(26) makes less than one error in 100,000,000,000
operations. To achieve this accuracy, however, cells use machines
(such as the enzyme DNA polymerase I) that proofread the copy and
correct errors. Assemblers may well need similar error-checking and
error-correcting abilities, if they are to produce reliable results.
-Will radiation disrupt molecular machines and render them unusable?
High-energy radiation can break chemical bonds and disrupt molecular
machines. Living cells once again show that solutions exist: they
operate for years by repairing and replacing radiation-damaged
parts.*(27) Because individual machines are so tiny, however, they
present small targets for radiation and are seldom hit. Still, if a
system of nanomachines must be reliable, then it will have to tolerate
a certain amount of damage, and damaged parts must regularly be
repaired or replaced. This approach to reliability is well known to
designers of aircraft and spacecraft.
-Since evolution has failed to produce assemblers, does this show
that they are either impossible or useless?
The earlier questions were answered in part by pointing to the
working molecular machinery of cells. This makes a simple and powerful
case that natural law permits small clusters of atoms to behave as
controlled machines, able to build other nanomachines. Yet despite
their basic resemblance to ribosomes, assemblers will differ from
anything found in cells; the things they do- while consisting of
ordinary molecular motions and reactions- will have novel results.
No cell, for example, makes diamond fiber.
The idea that new kinds of nanomachinery will bring new, useful
abilities may seem startling: in all its billions of years of
evolution, life has never abandoned*(28) its basic reliance on protein
machines. Does this suggest that improvements are impossible,
though? Evolution progresses through small changes, and evolution of
DNA cannot easily replace DNA. Since the DNA/RNA/ribosome system is
specialized to make proteins, life has had no real opportunity to
evolve an alternative. Any production manager can well appreciate
the reasons; even more than a factory, life cannot afford to shut down
to replace its old systems.
Improved molecular machinery should no more surprise us than alloy
steel being ten times stronger than bone, or copper wires transmitting
signals a million times faster than nerves. Cars outspeed cheetahs,
jets outfly falcons, and computers already outcalculate
head-scratching humans. The future will bring further examples of
improvements on biological evolution, of which second-generation
nanomachines will be but one.
In physical terms, it is clear enough why advanced assemblers will
be able to do more than existing protein machines. They will be
programmable like ribosomes, but they will be able to use a wider
range of tools than all the enzymes in a cell put together. Because
they will be made of materials far more strong, stiff, and stable than
proteins, they will be able to exert greater forces, move with greater
precision, and endure harsher conditions. Like an industrial robot
arm- but unlike anything in a living cell- they will be able to rotate
and move molecules in three dimensions under programmed control,
making possible the precise assembly of complex objects. These
advantages will enable them to assemble a far wider range of molecular
structures than living cells have done.
-Is there some special magic about life, essential to making
molecular machinery work?
One might doubt that artificial nanomachines could even equal the
abilities of nanomachines in the cell, if there were reason to think
that cells contained some special magic that makes them work. This
idea is called "vitalism." Biologists have abandoned it because they
have found chemical and physical explanations for every aspect of
living cells yet studied, including their motion, growth, and
reproduction. Indeed, this knowledge is the very foundation of
biotechnology.
Nanomachines floating in sterile test tubes, free of cells, have
been made to perform all the basic sorts of activities that they
perform inside living cells. Starting with chemicals that can be
made from smoggy air, biochemists have built working protein
machines without help from cells. R. B. Merrifield, for example,
used chemical techniques*(29) to assemble simple amino acids to make
bovine pancreatic ribonuclease, an enzymatic device that
disassembles RNA molecules. Life is special in structure, in behavior,
and in what it feels like from the inside to be alive, yet the laws of
nature that govern the machinery of life also govern the rest of the
universe.
-The case for the feasibility of assemblers and other nanomachines
may sound firm, but why not just wait and see whether they can be
developed?
Sheer curiosity seems reason enough to examine the possibilities
opened by nanotechnology, but there are stronger reasons. These
developments will sweep the world within ten to fifty years- that
is, within the expected lifetimes of ourselves or our families. What
is more, the conclusions of the following chapters suggest that a
wait-and-see policy would be very expensive- that it would cost many
millions of lives, and perhaps end life on Earth.
Is the case for the feasibility of nanotechnology and assemblers
firm enough that they should be taken seriously? It seems so,
because the heart of the case rests on two well-established facts of
science and engineering. These are (1) that existing molecular
machines serve a range of basic functions, and (2) that parts
serving these basic functions can be combined to build complex
machines. Since chemical reactions can bond atoms together in
diverse ways, and since molecular machines can direct chemical
reactions according to programmed instructions, assemblers
definitely are feasible.
-
NANOCOMPUTERS
-
Assemblers will bring one breakthrough of obvious and basic
importance: engineers will use them to shrink the size and cost of
computer circuits and speed their operation by enormous factors.
With today's bulk technology, engineers make patterns on silicon
chips by throwing atoms and photons at them, but the patterns remain
flat and molecular-scale flaws are unavoidable. With assemblers,
however, engineers will build circuits in three dimensions, and
build to atomic precision. The exact limits of electronic technology
today remain uncertain because the quantum behavior of electrons in
complex networks of tiny structures presents complex problems, some of
them resulting directly from the uncertainty principle. Whatever the
limits are, though, they will be reached with the help of assemblers.
The fastest computers will use electronic effects, but the
smallest may not. This may seem odd, yet the essence of computation
has nothing to do with electronics. A digital computer is a collection
of switches able to turn one another on and off. Its switches start in
one pattern (perhaps representing 2 + 2), then switch one another into
a new pattern (representing 4), and so on. Such patterns can represent
almost anything. Engineers build computers from tiny electrical
switches connected by wires simply because mechanical switches
connected by rods or strings would be big, slow, unreliable, and
expensive, today.
The idea of a purely mechanical computer is scarcely new. In England
during the mid-1800s, Charles Babbage*(30) invented a mechanical
computer built of brass gears; his co-worker Augusta Ada, the Countess
of Lovelace, invented computer programming. Babbage's endless
redesigning of the machine, problems with accurate manufacturing,
and opposition from budget-watching critics (some doubting the
usefulness of computers!), combined to prevent its completion.
In this tradition, Danny Hillis and Brian Silverman of the MIT
Artificial Intelligence Laboratory built a special-purpose
mechanical computer able to play tic-tac-toe. Yards on a side, full of
rotating shafts and movable frames that represent the state of the
board and the strategy of the game, it now stands in the Computer
Museum in Boston. It looks much like a large ball-and-stick
molecular model, for it is built of Tinkertoys.
Brass gears and Tinkertoys make for big, slow computers. With
components a few atoms wide, though, a simple mechanical computer
would fit within 1/100 of a cubic micron, many billions of times
more compact than today's so-called microelectronics. Even with a
billion bytes of storage, a nanomechanical computer could fit in a box
a micron wide,*(31) about the size of a bacterium. And it would be
fast. Although mechanical signals*(32) move about 100,000 times slower
than the electrical signals in today's machines, they will need to
travel only 1/1,000,000 as far, and thus will face less delay. So a
mere mechanical computer will work faster than the electronic
whirlwinds of today.
Electronic nanocomputers will likely be thousands of times faster
than electronic microcomputers- perhaps hundreds of thousands of times
faster, if a scheme proposed by Nobel Prize-winning physicist
Richard Feynman*(33) works out. Increased speed through decreased size
is an old story in electronics.
-
DISASSEMBLERS
-
Molecular computers will control molecular assemblers, providing the
swift flow of instructions needed to direct the placement of vast
numbers of atoms. Nanocomputers with molecular memory devices will
also store data generated by a process that is the opposite of
assembly.
Assemblers will help engineers synthesize things; their relatives,
disassemblers, will help scientists and engineers analyze things.
The case for assemblers rests on the ability of enzymes and chemical
reactions to form bonds, and of machines to control the process. The
case for disassemblers rests on the ability of enzymes and chemical
reactions to break bonds, and of machines to control the process.
Enzymes, acids, oxidizers, alkali metals, ions, and reactive groups of
atoms called free radicals- all can break bonds and remove groups of
atoms. Because nothing is absolutely immune to corrosion, it seems
that molecular tools will be able to take anything apart, a few
atoms at a time. What is more, a nanomachine could (at need or
convenience) apply mechanical force as well, in effect prying groups
of atoms free.
A nanomachine able to do this, while recording what it removes layer
by layer, is a disassembler.*(34) Assemblers, disassemblers, and
nanocomputers will work together. For example, a nanocomputer system
will be able to direct the disassembly of an object, record its
structure, and then direct the assembly of perfect copies. And this
gives some hint of the power of nanotechnology.
-
THE WORLD MADE NEW
-
Assemblers will take years to emerge, but their emergence seems
almost inevitable: Though the path to assemblers has many steps,
each step will bring the next in reach, and each will bring
immediate rewards. The first steps have already been taken, under
the names of "genetic engineering" and "biotechnology." Other paths to
assemblers seem possible. Barring worldwide destruction or worldwide
controls, the technology race will continue whether we wish it or not.
And as advances in computer-aided design speed the development of
molecular tools, the advance toward assemblers will quicken.
To have any hope of understanding our future, we must understand the
consequences of assemblers, disassemblers, and nanocomputers. They
promise to bring changes as profound as the industrial revolution,
antibiotics, and nuclear weapons all rolled up in one massive
breakthrough. To understand a future of such profound change, it makes
sense to seek principles of change that have survived the greatest
upheavals of the past. They will prove a useful guide.
2
The Principles of Change
-
Think of the design process*(35) as involving first the generation
of alternatives and then the testing of these alternatives against a
whole array of requirements and constraints.
-HERBERT A. SIMON
-
MOLECULAR ASSEMBLERS will bring a revolution without parallel
since the development of ribosomes, the primitive assemblers in the
cell. The resulting nanotechnology can help life spread beyond
Earth- a step without parallel since life spread beyond the seas. It
can help mind emerge in machines- a step without parallel since mind
emerged in primates. And it can let our minds renew and remake our
bodies- a step without any parallel at all.
These revolutions will bring dangers and opportunities too vast
for the human imagination to grasp. Yet the principles of change
that have applied to molecules, cells, beasts, minds, and machines
should endure even in an age of biotechnology, nanomachines, and
artificial minds. The same principles that have applied at sea, on
land, and in the air should endure as we spread Earth's life toward
the stars. Understanding the enduring principles of change will help
us understand the potential for good and ill in the new technologies.
-
ORDER FROM CHAOS
-
Order can emerge from chaos without anyone's giving orders:
orderly crystals condensed from formless interstellar gas long
before Sun, Earth, or life appeared. Chaos also gives rise to a
crystalline order under more familiar circumstances. Imagine a
molecule- perhaps regular in form, or perhaps lopsided and knobby like
a ginger root. Now imagine a vast number of such molecules moving
randomly in a liquid, tumbling and jostling like drunkards in
weightlessness in the dark. Imagine the liquid evaporating and
cooling, forcing the molecules closer together and slowing them
down. Will these randomly moving, oddly shaped molecules simply gather
in disordered heaps? Generally not. They will usually settle into a
crystalline pattern, each neatly nestled against its neighbors,
forming rows and columns as perfect as a checkerboard, though often
more complex.
This process involves neither magic nor some special property of
molecules and quantum mechanical forces. It does not even require
the special matching shapes that enable protein molecules to
self-assemble into machines. Marbles of uniform size, if placed in a
tray and shaken, also settle into a regular pattern.
Crystals grow by trial and the removal of error, by variation and
selection. No tiny hands assemble them. A crystal can begin with a
chance clumping of molecules: the molecules wander, bump, and clump at
random, but clumps stick best when packed in the right crystalline
pattern. Other molecules then strike this first, tiny crystal. Some
bump in the wrong position or orientation; they stick poorly and shake
loose again. Others happen to bump properly; they stick better and
often stay. Layer builds on layer, extending the crystalline
pattern. Though the molecules bump at random, they do not stick at
random. Order grows from chaos through variation and selection.
-
EVOLVING MOLECULES
-
In crystal growth, each layer forms a template for the next. Uniform
layers accumulate to form a solid block.
In cells, strands of DNA or RNA can serve as templates too, aided by
enzymes that act as molecular copying machines. But the subunits of
nucleic acid strands can be arranged in many different sequences,
and a template strand can separate from its copy. Both strand and
copy*(36) can then be copied again. Biochemist Sol Spiegelman*(37) has
used a copying machine (a protein from a virus) in test tube
experiments. In a simple, lifeless environment, it duplicates RNA
molecules.
Picture a strand of RNA floating in a test tube together with
copying machines and RNA subunits. The strand tumbles and writhes
until it bumps into a copying machine in the right position to
stick. Subunits bump around until one of the right kind meets the
copying machine in the right position to match the template strand. As
matching subunits chance to fall into position, the machine seizes
them and bonds them to the growing copy; though subunits bump
randomly, the machine bonds selectively. Finally the machine, the
template, and the copy separate.
In the terminology of Oxford zoologist Richard Dawkins,*(38)
things that give rise to copies of themselves are called
replicators. In this environment, RNA molecules qualify: a single
molecule soon becomes two, then four, eight, sixteen, thirty-two,
and so forth, multiplying exponentially. Later, the replication rate
levels off: the fixed stock of protein machines can churn out RNA
copies only so fast, no matter how many template molecules vie for
their services. Later still, the raw materials for making RNA
molecules become scarce and replication starves to a halt. The
exploding population of molecules reaches a limit to growth and
stops reproducing.
The copying machines, however, often miscopy an RNA strand,
inserting, deleting, or mismatching a subunit. The resulting mutated
strand then differs in length or subunit sequence. Such changes are
fairly random, and changes accumulate as miscopied molecules are again
miscopied. As the molecules proliferate, they begin to grow
different from their ancestors and from each other. This might seem
a recipe for chaos.
Biochemists have found that differing RNA molecules replicate at
differing rates, depending on their lengths and subunit patterns.
Descendants of the swifter replicators naturally grow more common.
Indeed, if one kind replicates just 10 percent more rapidly than its
siblings, then after one hundred generations, each of the faster
kind gives rise to 1,000 times as many descendants. Small
differences in exponential growth pile up exponentially.
When a test tube runs out of subunits, an experimenter can sample
its RNA and "infect" a fresh tube. The process begins again and the
molecules that dominated the first round of competition begin with a
head start. More small changes appear, building over time into large
changes. Some molecules replicate faster, and their kind dominates the
mix. When resources run out, the experimenter can sample the RNA and
start again (and again, and again), holding conditions stable.
This experiment reveals a natural process: no matter what RNA
sequences the experimenter starts with, the seeming chaos of random
errors and biased copying brings forth one kind of RNA molecule
(give or take some copying errors). Its typical version has a known,
well-defined sequence of 220 subunits. It is the best RNA replicator
in this environment, so it crowds out the others and stays.
Prolonged copying, miscopying, and competition always bring about
the same result, no matter what the length or pattern of the RNA
molecule that starts the process. Though no one could have predicted
this winning pattern, anyone can see that change and competition
will tend to bring forth a single winner. Little else could happen
in so simple a system. If these replicators affected one another
strongly (perhaps by selectively attacking or helping one another),
then the result could resemble a more complex ecology. As it is,
they just compete for a resource.
A variation on this example shows us something else: RNA molecules
adapt differently to different environments. A molecular machine
called a ribonuclease grabs RNA molecules having certain sequences
of exposed subunits and cuts them in two. But RNA molecules, like
proteins, fold in patterns that depend on their sequences, and by
folding the right way they can protect their vulnerable spots.
Experimenters find that RNA molecules evolve to sacrifice swift
replication for better protection when ribonuclease is around.
Again, a best competitor emerges.
Notice that biological terms have crept into this description: since
the molecules replicate, the word "generation" seems right;
molecules "descended" from a common "ancestor" are "relatives," and
the words "growth," "reproduction," "mutation," and "competition" also
seem right. Why is this? Because these molecules copy themselves
with small variations, as do the genes of living organisms. When
varying replicators have varying successes, the more successful tend
to accumulate. This process, wherever it occurs, is "evolution."
In this test tube example we can see evolution stripped to its
bare essentials, free of the emotional controversy surrounding the
evolution of life. The RNA replicators and protein copying machines
are well-defined collections of atoms obeying well-understood
principles and evolving in repeatable laboratory conditions.
Biochemists can make RNA and protein from off-the-shelf chemicals,
without help from life.
Biochemists borrow these copying machines from a kind of virus
that infects bacteria and uses RNA as its genetic material. These
viruses survive by entering a bacterium, getting themselves copied
using its resources, and then escaping to infect new bacteria.
Miscopying of viral RNA produces mutant viruses, and viruses that
replicate more successfully grow more common; this is evolution by
natural selection, apparently called "natural" because it involves
nonhuman parts of nature. But unlike the test tube RNA, viral RNA must
do more than just replicate itself as a bare molecule. Successful
viral RNA must also direct bacterial ribosomes to build protein
devices that let it first escape from the old bacterium, then
survive outside, and finally enter a new one. This additional
information makes viral RNA molecules about 4,500 subunits long.
To replicate successfully, the DNA of large organisms must do even
more, directing the construction of tens of thousands of different
protein machines and the development of complex tissues and organs.
This requires thousands of genes coded in millions to billions of
DNA subunits. Nevertheless, the essential process of evolution by
variation and selection remains the same in the test tube, in viruses,
and far beyond.
-
EXPLAINING ORDER
-
There are at least three ways to explain the structure of an evolved
population of molecular replicators, whether test tube RNA, viral
genes, or human genes. The first kind of explanation is a blow-by-blow
account of their histories: how specific mutations occurred and how
they spread. This is impossible without recording all the molecular
events, and such a record would in any event be immensely tedious.
The second kind of explanation resorts to a somewhat misleading
word: purpose. In detail, the molecules simply change haphazardly
and replicate selectively. Yet stepping back from the process, one
could describe the outcome by imagining that the surviving molecules
have changed to "achieve the goal" of replication. Why do RNA
molecules that evolved under the threat of ribonuclease fold as they
do? Because of a long and detailed history, of course, but the idea
that "they want to avoid attack and survive to replicate" would
predict the same result. The language of purpose makes useful
shorthand (try discussing human action without it!), but the
appearance of purpose need not result from the action of a mind. The
RNA example shows this quite neatly.
The third (and often best) kind of explanation- in terms of
evolution- says that order emerges through the variation and selection
of replicators. A molecule folds in a particular way because it
resembles ancestors that multiplied more successfully (by avoiding
attack, etc.), and left descendants including itself. As Richard
Dawkins points out,*(39) the language of purpose (if used carefully)
can be translated into the language of evolution.
Evolution attributes patterns of success to the elimination of
unsuccessful changes. It thus explains a positive as the result of a
double negative- an explanation of a sort that seems slightly
difficult to grasp. Worse, it explains something visible
(successful, purposeful entities) in terms of something invisible
(unsuccessful entities that have vanished). Because only successful
beasts have littered the landscape with the bones of their
descendants, the malformed failures of the past haven't even left many
fossils.
The human mind tends to focus on the visible, seeking positive
causes for positive results, an ordering force behind orderly results.
Yet through reflection we can see that this great principle has
changed our past and will shape our future: Evolution proceeds by
the variation and selection of replicators.
-
EVOLVING ORGANISMS
-
The history of life is the history of an arms race based on
molecular machinery. Today, as this race approaches a new and
swifter phase, we need to be sure we understand just how deeply rooted
evolution is. In a time when the idea of biological evolution is often
slighted in the schools and sometimes attacked, we should remember
that the supporting evidence is as solid as rock and as common as
cells.
In pages of stone, the Earth itself has recorded the history of
life. On lake bottoms and seabed, shells, bones, and silt have
piled, layer on layer. Sometimes a shifting current or a geological
upheaval has washed layers away; otherwise they have simply
deepened. Early layers, buried deep, have been crushed, baked,
soaked in mineral waters, and turned to stone.
For centuries, geologists have studied rocks to read Earth's past.
Long ago, they found seashells high in the crushed and crumpled rock
of mountain ranges. By 1785- seventy-four years before Darwin's
detested book*(40)- James Hutton had concluded that seabed mud had
been pressed to stone and raised skyward by forces not yet understood.
What else could geologists think, unless nature itself had lied?
They saw that fossil bones and shells differed from layer to
layer. They saw that shells in layers here matched shells in layers
there, though the layers might lie deep beneath the land between. They
named layers (A, B, C, D..., or Osagian, Meramecian, Lower Chesterian,
Upper Chesterian...), and used characteristic fossils to trace rock
layers. The churning of Earth's crust has nowhere left a complete
sequence of layers exposed, yet geologists finding A, B, C, D, E in
one place, C, D, E, F, G, H, I, J in another and J, K, L somewhere
else could see that A preceded L. Petroleum geologists (even those who
care nothing for evolution or its implications) still use such fossils
to date rock layers and to trace layers from one drill site to
another.
Scientists came to the obvious conclusion. Just as sea species today
live in broad areas, so did species in years gone by. Just as layer
piles on top of layer today, so did they then. Similar shells in
similar layers mark sediments laid down in the same age. Shells change
from layer to layer because species changed from age to age. This is
what geologists found written in shells and bones on pages of stone.
The uppermost layers of rock contain bones of recent animals, deeper
layers contain bones of animals now extinct. Still earlier layers show
no trace of any modern species. Below mammal bones lie dinosaur bones;
in older layers lie amphibian bones, then shells and fish bones, and
then no bones or shells at all. The oldest fossil-bearing rocks bear
the microscopic traces of single cells.
Radioactive dating shows these oldest traces to be several billion
years old. Cells more complex than bacteria date to little more than
one billion years ago. The history of worms, fish, amphibians,
reptiles, and mammals spans hundreds of millions of years.
Human-like bones date back several million years. The remains of
civilizations date back several thousand.
In three billion years, life evolved from single cells able to
soak up chemicals to collections of cells embodying minds able to soak
up ideas. Within the last century, technology has evolved from the
steam locomotive and electric light to the spaceship and the
electronic computer- and computers are already being taught to read
and write. With mind and technology, the rate of evolution has
jumped a millionfold or more.
-
Another Route Back
-
The book of stone records the forms of long-dead organisms, yet
living cells also carry records, genetic texts only now being read. As
with the ideas of geology, the essential ideas of evolution were known
before Darwin*(41) had set pen to paper.
In lamp-lit temples and monasteries, generations of scribes copied
and recopied manuscripts. Sometimes they miscopied words and
sentences- whether by accident, by perversity, or by order of the
local ruler- and as the manuscripts replicated, aided by these human
copying machines, errors accumulated. The worst errors might be caught
and removed, and famous passages might survive unchanged, but
differences grew.
Ancient books seldom exist in their original versions. The oldest
copies are often centuries younger than the lost originals.
Nonetheless, from differing copies with differing errors, scholars can
reconstruct versions closer to the original.
They compare texts. They can trace lines of descent from common
ancestors because unique patterns of errors betray copying from a
common source. (Schoolteachers know this: identical right answers
aren't a tipoff- unless on an essay test- but woe to students
sitting side by side who turn in tests with identical mistakes!) Where
all surviving copies agree, scholars can assume that the original copy
(or at least the last shared ancestor of the survivors) held the
same words. Where survivors differ, scholars study copies that
descended separately from a distant ancestor, because areas of
agreement then indicate a common origin in the ancestral version.
Genes resemble manuscripts written in a four-letter alphabet. Much
as a message can take many forms in ordinary language (restating an
idea using entirely different words is no great strain), so
different genetic wording can direct the construction of identical
protein molecules. Moreover, protein molecules with different design
details can serve identical functions. A collection of genes in a cell
is like a whole book, and genes- like old manuscripts- have been
copied and recopied by inaccurate scribes.
Like scholars studying ancient texts, biologists generally work with
modern copies of their material (with, alas, no biological Dead Sea
Scrolls from the early days of life). They compare organisms with
similar appearances (lions and tigers, horses and zebras, rats and
mice) and find that they give similar answers to the essay questions
in their genes and proteins. The more two organisms differ (lions
and lizards, humans and sunflowers), the more these answers differ,
even among molecular machines serving identical functions. More
telling still, similar animals make the same mistakes- all primates,
for example, lack enzymes for making vitamin C, an omission shared
by only two other known mammals, the guinea pig and the fruit bat.
This suggests that we primates have copied our genetic answers from
a shared source, long ago.
The same principle that shows the lines of descent of ancient
texts (and that helps correct their copying errors) thus also
reveals the lines of descent of modern life. Indeed, it indicates that
all known life shares a common ancestor.
-
The Rise of the Replicators
-
The first replicators on Earth evolved abilities beyond those
possible to RNA molecules replicating in test tubes. By the time
they reached the bacterial stage, they had developed the "modern"
system of using DNA, RNA, and ribosomes to construct protein.
Mutations then changed not only the replicating DNA itself, but
protein machines and the living structures they build and shape.
Teams of genes shaped ever more elaborate cells, then guided the
cellular cooperation that formed complex organisms. Variation and
selection favored teams of genes that shaped beasts with protective
skins and hungry mouths, animated by nerve and muscle, guided by eye
and brain. As Richard Dawkins puts it,*(42) genes built ever more
elaborate survival machines to aid their own replication.
When dog genes replicate, they often shuffle with those of other
dogs that have been selected by people, who then select which
puppies to keep and breed. Over the millennia, people have molded
wolf-like beasts into greyhounds, toy poodles, dachshunds, and Saint
Bernards. By selecting which genes survive, people have reshaped
dogs in both body and temperament. Human desires have defined
success for dog genes; other pressures have defined success for wolf
genes.
Mutation and selection of genes has, through long ages, filled the
world with grass and trees, with insects, fish, and people. More
recently, other things have appeared and multiplied- tools, houses,
aircraft, and computers. And like the lifeless RNA molecules, this
hardware has evolved.
-
EVOLVING TECHNOLOGY
-
As the stone of Earth records the emergence of ever more complex and
capable forms of life, so the relics and writings of humanity record
the emergence of ever more complex and capable forms of hardware.
Our oldest surviving hardware is itself stone, buried with the fossils
of our ancestors; our newest hardware orbits overhead.
Consider for a moment the hybrid ancestry of the space shuttle. On
its aircraft side, it descends from the aluminum jets of the
sixties, which themselves sprang from a line stretching back through
the aluminum prop planes of World War II, to the wood-and-cloth
biplanes of World War I, to the motorized gliders of the Wright
brothers, to toy gliders and kites. On its rocket side, the shuttle
traces back to Moon rockets, to military missiles, to last century's
artillery rockets ("and the rocket's red glare..."), and finally to
fireworks and toys. This aircraft/rocket hybrid flies, and by
varying components and designs, aerospace engineers will evolve
still better ones.
Engineers speak of "generations" of technology; Japan's
"fifth-generation" computer project shows how swiftly some
technologies grow and spawn. Engineers speak of "hybrids," of
"competing technologies," and of their "proliferation." IBM Director
of Research Ralph E. Gomory emphasizes the evolutionary nature of
technology, writing that "technology development is much more
evolutionary and much less revolutionary or breakthrough-oriented than
most people imagine." (Indeed, even breakthroughs as important as
molecular assemblers will develop through many small steps.) In the
quote that heads this chapter, Professor Herbert A. Simon of
Carnegie-Mellon University urges us to "think of the design process as
involving first the generation of alternatives and then the testing of
these alternatives against a whole army of requirements and
constraints." Generation and testing of alternatives is synonymous
with variation and selection.
Sometimes various alternatives already exist. In "One Highly Evolved
Toolbox," in The Next Whole Earth Catalog,*(43) J. Baldwin writes:
"Our portable shop has been evolving for about twenty years now.
There's nothing really very special about it except that a
continuing process of removing obsolete or inadequate tools and
replacing them with more suitable ones has resulted in a collection
that has become a thing-making system rather than a pile of hardware."
Baldwin uses the term "evolving" accurately. Invention and
manufacture have for millennia generated variations in tool designs,
and Baldwin has winnowed the current crop by competitive selection,
keeping those that work best with his other tools to serve his
needs. Through years of variation and selection, his system evolved- a
process he highly recommends. Indeed, he urges that one never try to
plan out the purchase of a complete set of tools. Instead, he urges
buying the tools one often borrows, tools selected not by theory but
by experience.
Technological variations are often deliberate, in the sense that
engineers are paid to invent and test. Still, some novelties are sheer
accident, like the discovery of a crude form of Teflon in a cylinder
supposedly full of tetrafluoroethylene gas: with its valve open, it
remained heavy; when it was sawed open, it revealed a strange, waxy
solid. Other novelties have come from systematic blundering. Edison
tried carbonizing everything from paper to bamboo to spiderwebs when
he was seeking a good light-bulb filament. Charles Goodyear messed
around in a kitchen for years, trying to convert gummy natural
rubber into a durable substance, until at last he chanced to drop
sulfurized rubber on a hot stove, performing the first crude
vulcanization.
In engineering, enlightened trial and error, not the planning of
flawless intellects, has brought most advances; this is why
engineers build prototypes. Peters and Waterman*(44) in their book
In Search of Excellence show that the same holds true of advances in
corporate products and policies. This is why excellent companies
create "an environment and a set of attitudes that encourage
experimentation," and why they evolve "in a very Darwinian way."
Factories bring order through variation and selection. Crude
quality-control systems test and discard faulty parts before
assembling products, and sophisticated quality-control systems use
statistical methods to track defects to their sources, helping
engineers change the manufacturing process to minimize defects.
Japanese engineers, building on W. Edwards Deming's work in
statistical quality control, have made such variation and selection of
industrial processes a pillar of their country's economic success.
Assembler-based systems will likewise need to measure results to
eliminate flaws.
Quality control is a sort of evolution, aiming not at change but
at eliminating harmful variations. But just as Darwinian evolution can
preserve and spread favorable mutations, so good quality control
systems can help managers and workers to preserve and spread more
effective processes, whether they appear by accident or by design.
All this tinkering by engineers and manufacturers prepares
products for their ultimate test. Out in the market, endless varieties
of wrench, car, sock, and computer compete for the favor of buyers.
When informed buyers are free to choose, products that do too little
or cost too much eventually fail to be re-produced. As in nature,
competitive testing makes yesterday's best competitor into
tomorrow's fossil. "Ecology" and "economy" share more than
linguistic roots.
Both in the marketplace and on real and imaginary battlefields,
global competition drives organizations to invent, buy, beg, and steal
ever more capable technologies. Some organizations compete chiefly
to serve people with superior goods, others compete chiefly to
intimidate them with superior weapons. The pressures of evolution
drive both.
The global technology race has been accelerating for billions of
years. The earthworm's blindness could not block the development of
sharp-eyed birds. The bird's small brain and clumsy wings could not
block the development of human hands, minds, and shotguns. Likewise,
local prohibitions cannot block advances in military and commercial
technology. It seems that we must guide the technology race or die,
yet the force of technological evolution makes a mockery of
anti-technology movements: democratic movements for local restraint
can only restrain the world's democracies, not the world as a whole.
The history of life and the potential of new technology suggest some
solutions, but this is a matter for Part Three.
-
THE EVOLUTION OF DESIGN
-
It might seem that design offers an alternative to evolution, but
design involves evolution in two distinct ways. First, design practice
itself evolves. Not only do engineers accumulate designs that work,
they accumulate design methods that work. These range from handbook
standards for choosing pipes to management systems for organizing
research and development. And as Alfred North Whitehead stated,*(45)
"The greatest invention of the nineteenth century was the invention of
the method of invention."
Second, design itself proceeds by variation and selection. Engineers
often use mathematical laws evolved to describe (for example) heat
flow and elasticity to test simulated designs before building them.
They thus evolve plans through a cycle of design, calculation,
criticism, and redesign, avoiding the expense of cutting metal. The
creation of designs thus proceeds through a nonmaterial form of
evolution.
Hooke's law, for example, describes how metal bends and stretches:
deformation is proportional to the applied stress: twice the pull,
twice the stretch. Though only roughly correct, it remains fairly
accurate until the metal's springiness finally yields to stress.
Engineers can use a form of Hooke's law to design a bar of metal
that can support a load without bending too far- and then make it just
a bit thicker to allow for inaccuracies in the law and in their design
calculations. They can also use a form of Hooke's law to describe
the bending and twisting of aircraft wings, tennis rackets, and
automobile frames. But simple mathematical equations don't wrap
smoothly around such convoluted structures. Engineers have to fit
the equations to simpler shapes (to pieces of the design), and then
assemble these partial solutions to describe the flexing of the whole.
It is a method (called "finite element analysis") that typically
requires immense calculations, and without computers it would be
impractical. With them, it has grown common.
Such simulations extend an ancient trend. We have always imagined
consequences, in hope and fear, when we have needed to select a course
of action. Simpler mental models (whether inborn or learned)
undoubtedly guide animals as well. When based on accurate mental
models, thought experiments can replace more costly (or even deadly)
physical experiments- a development evolution has favored. Engineering
simulations simply extend this ability to imagine consequences, to
make our mistakes in thought rather than deed.
In "One Highly Evolved Toolbox," J. Baldwin discusses how tools
and thought mesh in job-shop work: "You begin to build your tool
capability into the way you think about making things. As anyone who
makes a lot of stuff will tell you, the tools soon become sort of an
automatic part of the design process... But tools can't become part of
your design process if you don't know what is available and what the
various tools do."
Having a feel for tool capabilities is essential when planning a
job-shop project for delivery next Wednesday; it is equally
essential when shaping a strategy for handling the breakthroughs of
the coming decades. The better our feel for the future's tools, the
sounder will be our plans for surviving and prospering.
A craftsman in a job shop can keep tools in plain sight; working
with them every day makes them familiar to his eyes, hands, and
mind. He gets to know their abilities naturally, and can put this
knowledge to immediate creative use. But people- like us- who have
to understand the future face a greater challenge, because the
future's tools exist now only as ideas and as possibilities implicit
in natural law. These tools neither hang on the wall nor impress
themselves on the mind through sight and sound and touch- nor will
they, until they exist as hardware. In the coming years of preparation
only study, imagination, and thought*(46) can make their abilities
real to the mind.
-
WHAT ARE THE NEW REPLICATORS?
-
History shows us that hardware evolves. Test tube RNA, viruses,
and dogs all show how evolution proceeds by the modification and
testing of replicators. But hardware (today) cannot reproduce
itself- so where are the replicators behind the evolution of
technology? What are the machine genes?
Of course, we need not actually identify replicators in order to
recognize evolution. Darwin described evolution before Mendel
discovered genes, and geneticists learned much about heredity before
Watson and Crick discovered the structure of DNA. Darwin needed no
knowledge of molecular genetics to see that organisms varied and
that some left more descendants.
A replicator is a pattern that can get copies of itself made. It may
need help; without protein machines to copy it, DNA could not
replicate. But by this standard, some machines are replicators!
Companies often make machines that fall into the hands of a
competitor; the competitor then learns their secrets and builds
copies. Just as genes "use" protein machines to replicate, so such
machines "use" human minds and hands to replicate. With
nanocomputers directing assemblers and disassemblers, the
replication of hardware could even be automated.
The human mind, though, is a far subtler engine of imitation than
any mere protein machine or assembler. Voice, writing, and drawing can
transmit designs from mind to mind before they take form as
hardware. The ideas behind methods of design are subtler yet: more
abstract than hardware, they replicate and function exclusively in the
world of minds and symbol systems.
Where genes have evolved over generations and eons, mental
replicators now evolve over days and decades. Like genes, ideas split,
combine, and take multiple forms (genes can be transcribed from DNA to
RNA and back again; ideas can be translated from language to
language). Science cannot yet describe the neural patterns that embody
ideas in brains, but anyone can see that ideas mutate, replicate,
and compete. Ideas evolve.
Richard Dawkins calls*(47) bits of replicating mental patterns
"memes" (meme rhymes with cream). He says "examples of memes are
tunes, ideas, catch-phrases, clothes fashions, ways of making pots
or of building arches. Just as genes propagate themselves in the
gene pool by leaping from body to body [generation to generation]
via sperms or eggs, so memes propagate themselves in the meme pool
by leaping from brain to brain via a process which, in the broad
sense, can be called imitation."
-
THE CREATURES OF THE MIND
-
Memes replicate because people both learn and teach. They vary
because people create the new and misunderstand the old. They are
selected (in part) because people don't believe or repeat everything
they hear. As test tube RNA molecules compete for scarce copying
machines and subunits, so memes must compete for a scarce resource-
human attention and effort. Since memes shape behavior, their
success or failure is a deadly serious matter.
Since ancient times, mental models and patterns of behavior have
passed from parent to child. Meme patterns that aid survival and
reproduction have tended to spread. (Eat this root only after cooking;
don't eat those berries, their evil spirits will twist your guts.)
Year by year, people varied their actions with varying results. Year
by year, some died while others found new tricks of survival and
passed them on. Genes built brains skilled at imitation because the
patterns imitated were, on the whole, of value- their bearers, after
all, had survived to spread them.
Memes themselves, though, face their own matters of "life" and
"death": as replicators, they evolve solely to survive and spread.
Like viruses, they can replicate without aiding their host's
survival or well-being. Indeed, the meme for martyrdom-in-a-cause
can spread itself through the very act of killing its host.
Genes, like memes, survive by many strategies. Some duck genes
have spread themselves by encouraging ducks to pair off to care for
their gene-bearing eggs and young. Some duck genes have spread
themselves (when in male ducks) by encouraging rape, and some (when in
female ducks) by encouraging the planting of eggs in other ducks'
nests. Still other genes found in ducks are virus genes, able to
spread without making more ducks. Protecting eggs helps the duck
species (and the individual duck genes) survive; rape helps one set of
duck genes at the expense of others; infection helps viral genes at
the expense of duck genes in general. As Richard Dawkins points out,
genes "care" only about their own replication: they appear selfish.
But selfish motives can encourage cooperation.*(48) People seeking
money and recognition for themselves cooperate to build corporations
that serve other people's wants. Selfish genes cooperate to build
organisms that themselves often cooperate. Even so, to imagine that
genes automatically serve some greater good (-of their chromosome?-
their cell?- their body?- their species?) is to mistake a common
effect for an underlying cause. To ignore the selfishness of
replicators is to be lulled by a dangerous illusion.
Some genes in cells are out-and-out parasites. Like herpes genes
inserted in human chromosomes, they exploit cells and harm their
hosts. Yet if genes can be parasites, why not memes as well?
In The Extended Phenotype,*(49) Richard Dawkins describes a worm
that parasitizes bees and completes its life cycle in water. It gets
from bee to water by making the host bee dive to its death. Similarly,
ant brainworms must enter a sheep to complete their life cycle. To
accomplish this, they burrow into the host ant's brain, somehow
causing changes that make the ant "want" to climb to the top of a
grass stem and wait, eventually to be eaten by a sheep.
As worms enter other organisms and use them to survive and
replicate, so do memes. Indeed, the absence of memes exploiting people
for their own selfish ends would be amazing, a sign of some
powerful- indeed, nearly perfect- mental immune system. But
parasitic memes clearly do exist. Just as viruses evolve to
stimulate cells to make viruses, so rumors evolve to sound plausible
and juicy, stimulating repetition. Ask not whether a rumor is true,
ask instead how it spreads. Experience shows that ideas evolved to
be successful replicators need have little to do with the truth.
At best, chain letters, spurious rumors, fashionable lunacies, and
other mental parasites harm people by wasting their time. At worst,
they implant deadly misconceptions. These meme systems exploit human
ignorance and vulnerability. Spreading them is like having a cold
and sneezing on a friend. Though some memes act much like viruses,
infectiousness isn't necessarily bad (think of an infectious grin,
or infectious good nature). If a package of ideas has merit, then
its infectiousness simply increases its merit- and indeed, the best
ethical teachings also teach us to teach ethics. Good publications may
entertain, enrich understanding, aid judgment- and advertise gift
subscriptions. Spreading useful meme systems is like offering useful
seeds to a friend with a garden.
-
SELECTING IDEAS
-
Parasites have forced organisms to evolve immune systems, such as
the enzymes that bacteria use to cut up invading viruses, or the
roving white blood cells our bodies use to destroy bacteria. Parasitic
memes have forced minds down a similar path, evolving meme systems
that serve as mental immune systems.
The oldest and simplest mental immune system simply commands
"believe the old, reject the new." Something like this system
generally kept tribes from abandoning old, tested ways in favor of
wild new notions- such as the notion that obeying alleged ghostly
orders to destroy all the tribe's cattle and grain would somehow bring
forth a miraculous abundance of food and armies of ancestors to
drive out foreigners. (This meme package infected the Xhosa
people*(50) of southern Africa in 1856; by the next year 68,000 had
died, chiefly of starvation.)
Your body's immune system follows a similar rule: it generally
accepts all the cell types present in early life and rejects new
types, such as potential cancer cells and invading bacteria, as
foreign and dangerous. This simple reject-the-new system once worked
well, yet in this era of organ transplantation it can kill. Similarly,
in an era when science and technology regularly present facts that are
both new and trustworthy, a rigid mental immune system becomes a
dangerous handicap.
For all its shortcomings, though, the reject-the-new principle is
simple and offers real advantages. Tradition holds much that is
tried and true (or if not true, then at least workable). Change is
risky: just as most mutations are bad, so most new ideas are wrong.
Even reason can be dangerous: if a tradition links sound practices
to a fear of ghosts, then overconfident rational thought may throw out
the good with the bogus. Unfortunately, traditions evolved to be
good may have less appeal than ideas evolved to sound good- when first
questioned, the soundest tradition may be displaced by worse ideas
that better appeal to the rational mind.
Yet memes that seal the mind against new ideas protect themselves in
a suspiciously self-serving way. While protecting valuable
traditions from clumsy editing, they may also shield parasitic
claptrap from the test of truth. In times of swift change they can
make minds dangerously rigid.
Much of the history of philosophy and science may be seen as a
search for better mental immune systems, for better ways to reject the
false, the worthless, and the damaging. The best systems respect
tradition, yet encourage experiment. They suggest standards for
judging memes, helping the mind distinguish between parasites and
tools.
-
The principles of evolution provide a way to view change, whether in
molecules, organisms, technologies, minds, or cultures. The same basic
questions keep arising: What are the replicators? How do they vary?
What determines their success? How do they defend against invaders?
These questions will arise again when we consider the consequences
of the assembler revolution, and yet again when we consider how
society might deal with those consequences.
The deep-rooted principles of evolutionary change will shape the
development of nanotechnology, even as the distinction between
hardware and life begins to blur. These principles show much about
what we can and cannot hope to achieve, and they can help us focus our
efforts to shape the future. They also tell us much about what we
can and cannot foresee, because they guide the evolution not only of
hardware, but of knowledge itself.
3
Predicting and Projecting
-
The critical attitude*(51) may be described as the conscious attempt
to make our theories, our conjectures, suffer in our stead in the
struggle for the survival of the fittest. It gives us a chance to
survive the elimination of an inadequate hypothesis- when a more
dogmatic attitude would eliminate it by eliminating us.
-Sir KARL POPPER
-
AS WE LOOK FORWARD to see where the technology race leads, we should
ask three questions. What is possible, what is achievable, and what is
desirable?
First, where hardware is concerned, natural law sets limits to the
possible. Because assemblers will open a path to those limits,
understanding assemblers is a key to understanding what is possible.
Second, the principles of change and the facts of our present
situation set limits to the achievable. Because evolving replicators
will play a basic role, the principles of evolution are a key to
understanding what will be achievable.
As for what is desirable or undesirable, our differing dreams spur a
quest for a future with room for diversity, while our shared fears
spur a quest for a future of safety.
These three question- of the possible, the achievable, and the
desirable- frame an approach to foresight. First, scientific and
engineering knowledge form a map of the limits of the possible. Though
still blurred and incomplete, this map outlines the permanent limits
within which the future must move. Second, evolutionary principles
determine what paths lie open, and set limits to achievement-
including lower limits, because advances that promise to improve
life or to further military power will be virtually unstoppable.
This allows a limited prediction: If the eons-old evolutionary race
does not somehow screech to a halt, then competitive pressures will
mold our technological future to the contours of the limits of the
possible. Finally, within the broad confines of the possible and the
achievable, we can try to reach a future we find desirable.
-
PITFALLS OF PROPHECY
-
But how can anyone predict the future? Political and economic trends
are notoriously fickle, and sheer chance rolls dice across continents.
Even the comparatively steady advance of technology often eludes
prediction.
Prognosticators often guess at the times and costs required to
harness new technologies. When they reach beyond outlining
possibilities and attempt accurate predictions, they generally fail.
For example, though the space shuttle was clearly possible,
predictions of its cost and initial launch date were wrong by
several years and billions of dollars. Engineers cannot accurately
predict when a technology will be developed, because development
always involves uncertainties.
But we have to try to predict and guide development. Will we develop
monster technologies before cage technologies, or after? Some
monsters, once loosed, cannot be caged. To survive, we must keep
control by speeding some developments and slowing others.
Though one technology can sometimes block the dangers of another
(defense vs. offense, pollution controls vs. pollution), competing
technologies often go in the same direction. On December 29, 1959,
Richard Feynman (now a Nobel laureate) gave a talk*(52) at an annual
meeting of the American Physical Society entitled "There's Plenty of
Room at the Bottom." He described a non-biochemical approach to
nanomachinery (working down, step by step, using larger machines to
build smaller machines), and stated that the principles of physics "do
not speak against the possibility of maneuvering things atom by
atom. It is not an attempt to violate any laws; it is something, in
principle, that can be done; but, in practice, it has not been done
because we are too big.... Ultimately, we can do chemical
synthesis.... put the atoms down where the chemist says, and so you
make the substance." In brief, he sketched another, nonbiochemical
path to the assembler. He also stated, even then, that it is "a
development which I think cannot be avoided."
As I will discuss in Chapters 4 and 5, assemblers and intelligent
machines will simplify many questions regarding the time and cost of
technological developments. But questions of time and cost will
still muddy our view of the period between the present and these
breakthroughs. Richard Feynman saw in 1959 that nanomachines could
direct chemical synthesis, presumably including the synthesis of
DNA. Yet he could foresee neither the time nor the cost of doing so.
In fact, of course, biochemists developed techniques for making
DNA without programmable nanomachines, using shortcuts based on
specific chemical tricks. Winning technologies often succeed because
of unobvious tricks and details. In the mid-1950s physicists could see
that basic semiconductor principles made microcircuits physically
possible, but foreseeing how they would be made- foreseeing the
details of mask-making, resists, oxide growth, ion implantation,
etching, and so forth, in all their complexity- would have been
impossible. The nuances of detail and competitive advantage that
select winning technologies make the technology race complex and its
path unpredictable.
But does this make long-term forecasting futile? In a race toward
the limits set by natural law, the finish line is predictable even
if the path and the pace of the runners are not. Not human whims but
the unchanging laws of nature draw the line between what is physically
possible and what is not- no political act, no social movement can
change the law of gravity one whit. So however futuristic they may
seem, sound projections of technological possibilities are quite
distinct from predictions. They rest on timeless laws of nature, not
on the vagaries of events.
It is unfortunate that this insight remains rare. Without it, we
stumble in a daze across the landscape of the possible, confusing
mountains with mirages and discounting both. We look ahead with
minds and cultures rooted in the ideas of more sluggish times, when
both science and technological competition lacked their present
strength and speed. We have only recently begun to evolve a
tradition of technological foresight.
-
SCIENCE AND NATURAL LAW
-
Science and technology intertwine. Engineers use knowledge
produced by scientists; scientists use tools produced by engineers.
Scientists and engineers both work with mathematical descriptions of
natural laws and test ideas with experiments. But science and
technology differ radically in their basis, methods, and aims.
Understanding these differences is crucial to sound foresight.
Though both fields consist of evolving meme systems, they evolve under
different pressures. Consider the roots of scientific knowledge.
Through most of history, people had little understanding of
evolution. This left philosophers thinking that sensory evidence,
through reason, must somehow imprint on the mind all human
knowledge- including knowledge of natural law. But in 1737, the
Scottish philosopher David Hume presented them with a nasty puzzle: he
showed that observations cannot logically prove a general rule, that
the Sun shining day after day proves nothing, logically, about its
shining tomorrow. And indeed, someday the Sun will fail, disproving
any such logic. Hume's problem appeared to destroy the idea of
rational knowledge, greatly upsetting rational philosophers (including
himself). They thrashed and sweated, and irrationalism gained
ground. In 1945, philosopher Bertrand Russell observed*(53) that
"the growth of unreason throughout the nineteenth century and what has
passed of the twentieth is a natural sequel to Hume's destruction of
empiricism." Hume's problem-meme had undercut the very idea of
rational knowledge, at least as people had imagined it.
In recent decades, Karl Popper (perhaps the scientists' favorite
philosopher of science), Thomas Kuhn, and others have recognized
science as an evolutionary process. They see it not as a mechanical
process by which observations somehow generate conclusions, but as a
battle where ideas compete for acceptance.
All ideas, as memes, compete for acceptance, but the meme system
of science is special: it has a tradition of deliberate idea mutation,
and a unique immune system for controlling the mutants. The results of
evolution vary with the selective pressures applied, whether among
test tube RNA molecules, insects, ideas, or machines. Hardware evolved
for refrigeration differs from hardware evolved for transportation,
hence refrigerators make very poor cars. In general, replicators
evolved for A differ from those evolved for B. Memes are no exception.
Broadly speaking, ideas can evolve to seem true or they can evolve
to be true*(54) (by seeming true to people who check ideas carefully).
Anthropologists and historians have described what happens when
ideas evolve to seem true among people lacking the methods of science;
the results (the evil-spirit theory of disease, the lights-on-a-dome
theory of stars, and so forth) were fairly consistent worldwide.
Psychologists probing people's naive misconceptions about how
objects fall have found beliefs like those that evolved into formal
"scientific" systems during the Middle Ages, before the work of
Galileo and Newton.
Galileo and Newton used experiments and observations to test ideas
about objects and motion, beginning an era of dramatic scientific
progress: Newton evolved a theory that survived every test then
available. Their method of deliberate testing killed off ideas that
strayed too far from the truth, including ideas that had evolved to
appeal to the naive human mind.
This trend has continued. Further variation and testing have
forced the further evolution of scientific ideas, yielding some as
bizarre-seeming as the varying time and curved space of relativity, or
the probabilistic particle wave functions of quantum mechanics. Even
biology has discarded the special life-force expected by early
biologists, revealing instead elaborate systems of invisibly small
molecular machines. Ideas evolved to be true (or close to the truth)
have again and again turned out to seem false- or incomprehensible.
The true and the true-seeming have turned out to be as different as
cars and refrigerators.
Ideas in the physical sciences have evolved under several basic
selection rules. First, scientists ignore ideas that lack testable
consequences; they thus keep their heads from being clogged by useless
parasites. Second, scientists seek replacements for ideas that have
failed tests. Finally, scientists seek ideas that make the widest
possible range of exact predictions. The law of gravity, for
example, describes how stones fall, planets orbit, and galaxies swirl,
and makes exact predictions that leave it wide open to disproof. Its
breadth and precision likewise give it broad usefulness, helping
engineers both to design bridges and to plan spaceflights.
The scientific community provides an environment where such memes
spread, forced by competition and testing to evolve toward power and
accuracy. Agreement on the importance of testing theories holds the
scientific community together through fierce controversies over the
theories themselves.
Inexact, limited evidence can never prove an exact, general theory
(as Hume showed), but it can disprove some theories and so help
scientists choose among them. Like other evolutionary processes,
science creates something positive (a growing store of useful
theories) through a double negative (disproof of incorrect
theories). The central role of negative evidence accounts for some
of the mental upset caused by science: as an engine of disproof, it
can uproot cherished beliefs, leaving psychological voids that it need
not refill.
In practical terms, of course, much scientific knowledge is as solid
as a rock dropped on your toe. We know Earth circles the Sun (though
our senses suggest otherwise) because the theory fits endless
observations, and because we know why our senses are fooled. We have
more than a mere theory that atoms exist: we have bonded them to
form molecules, tickled light from them, seen them under microscopes
(barely), and smashed them to pieces. We have more than a mere
theory of evolution: we have observed mutations, observed selection,
and observed evolution in the laboratory. We have found the traces
of past evolution in our planet's rocks, and have observed evolution
shaping our tools, our minds, and the ideas in our minds- including
the idea of evolution itself. The process of science has hammered
out a unified explanation of many facts, including how people and
science themselves came to be.
When science finishes disproving theories, the survivors often
huddle so close together*(55) that the gap between them makes no
practical difference. After all, a practical difference between two
surviving theories could be tested and used to disprove one of them.
The differences among modern theories of gravity, for instance, are
far too subtle to trouble engineers who are planning flights through
the gravity fields of space. In fact, engineers plan spaceflights
using Newton's disproved theory because it is simpler than Einstein's,
and is accurate enough. Einstein's theory of gravity has survived
all tests so far, yet there is no absolute proof for it and there
never will be. His theory makes exact predictions about everything
everywhere (at least about gravitational matters), but scientists
can only make approximate measurements of some things somewhere.
And, as Karl Popper points out,*(56) one can always invent a theory so
similar to another that existing evidence cannot tell them apart.
Though media debates highlight the shaky, disputed borders of
knowledge, the power of science to build agreement remains clear.
Where else has agreement on so much grown so steadily and so
internationally? Surely not in politics, religion, or art. Indeed, the
chief rival of science is a relative: engineering, which also
evolves through proposals and rigorous testing.
-
SCIENCE VS. TECHNOLOGY
-
As IBM Director of Research Ralph E. Gomory says,*(57) "The
evolution of technology development is often confused with science
in the public mind." This confusion muddles our efforts at foresight.
Though engineers often tread uncertain ground, they are not doomed
to do so, as scientists are. They can escape the inherent risks of
proposing precise, universal scientific theories. Engineers need
only show that under particular conditions particular objects will
perform well enough. A designer need know neither the exact stress
in a suspension bridge cable nor the exact stress that will break
it; the cable will support the bridge so long as the first remains
below the second, whatever they may be.
Though measurements cannot prove precise equality, they can prove
inequality. Engineering results can thus be solid in a way that
precise scientific theories cannot. Engineering results can even
survive disproof of the scientific theories supporting them, when
the new theory gives similar results. The case for assemblers, for
example, will survive any possible refinements in our theory of
quantum mechanics and molecular bonds.
Predicting the content of new scientific knowledge is logically
impossible because it makes no sense to claim to know already the
facts you will learn in the future. Predicting the details of future
technology, on the other hand, is merely difficult. Science aims at
knowing, but engineering aims at doing; this lets engineers speak of
future achievements without paradox. They can evolve their hardware in
the world of mind and computation, before cutting metal or even
filling in all the details of a design.
Scientists commonly recognize this difference between scientific
foresight and technological foresight: they readily make technological
predictions about science. Scientists could and did predict the
quality of Voyager's pictures of Saturn's rings, for example, though
not their surprising content. Indeed, they predicted the pictures'
quality while the cameras were as yet mere ideas and drawings. Their
calculations used well-tested principles of optics, involving no new
science.
Because science aims to understand how everything works,
scientific training can be a great aid in understanding specific
pieces of hardware. Still, it does not automatically bring engineering
expertise; designing an airliner requires much more than a knowledge
of the sciences of metallurgy and aerodynamics.
Scientists are encouraged by their colleagues and their training
to focus on ideas that can be tested with available apparatus. The
resulting short-term focus often serves science well: it keeps
scientists from wandering off into foggy worlds of untested fantasy,
and swift testing makes for an efficient mental immune system.
Regrettably, though, this cultural bias toward short-term testing
may make scientists less interested in long-term advances in
technology.
The impossibility of genuine foresight regarding science leads
many scientists to regard all statements about future developments
as "speculative"- a term that makes perfect sense when applied to
the future of science, but little sense when applied to
well-grounded projections in technology. But most engineers share
similar leanings toward the short term. They too are encouraged by
their training, colleagues, and employers to focus on just one kind of
problem: the design of systems that can be made with present
technology or with technology just around the corner. Even long-term
engineering projects like the space shuttle must have a technology
cutoff date after which no new developments can become part of the
basic design of the system.
In brief, scientists refuse to predict future scientific
knowledge, and seldom discuss future engineering developments.
Engineers do project future developments, but seldom discuss any not
based on present abilities. Yet this leaves a crucial gap: what of
engineering developments firmly based on present science but
awaiting future abilities? This gap leaves a fruitful area for study.
Imagine a line of development which involves using existing tools to
build new tools, then using those tools to build novel hardware
(perhaps including yet another generation of tools). Each set of tools
may rest on established principles, yet the whole development sequence
may take many years, as each step brings a host of specific problems
to iron out. Scientists planning their next experiment and engineers
designing their next device may well ignore all but the first step.
Still, the end result may be foreseeable, lying well within the bounds
of the possible shown by established science.
Recent history illustrates this pattern. Few engineers considered
building space stations before rockets reached orbit, but the
principles were clear enough, and space systems engineering is now a
thriving field. Similarly, few mathematicians and engineers studied
the possibilities of computation until computers were built, though
many did afterward. So it is not too surprising that few scientists
and engineers have yet examined the future of nanotechnology,
however important it may become.
-
THE LESSON OF LEONARDO
-
Efforts to project engineering developments have a long history, and
past examples illustrate present possibilities. For example, how did
Leonardo da Vinci succeed in foreseeing so much, and why did he
sometimes fail?
Leonardo lived five hundred years ago, his life spanning the
discovery of the New World. He made projections in the form of
drawings and inventions; each design may be seen as a projection
that something much like it could be made to work. He succeeded as a
mechanical engineer: he designed workable devices (some were not to be
built for centuries) for excavating, metalworking, transmitting power,
and other purposes. He failed as an aircraft engineer: we now know
that his flying machines could never be made to work as described.
His successes at machine design are easy to understand. If parts can
be made accurately enough, of a hard enough, strong enough material,
then the design of slow-moving machines with levers, pulleys, and
rolling bearings becomes a matter of geometry and leverage. Leonardo
understood these quite well. Some of his "predictions" were
long-range, but only because many years passed before people learned
to make parts precise enough, hard enough, and strong enough to
build (for instance) good ball bearings- their use came some three
hundred years after Leonardo proposed them. Similarly, gears with
superior, cycloidal teeth went unmade for almost two centuries after
Leonardo drew them, and one of his chain-drive designs went unbuilt
for almost three centuries.
His failures with aircraft are also easy to understand. Because
Leonardo's age lacked a science of aerodynamics, he could neither
calculate the forces on wings nor know the requirements for aircraft
power and control.
Can people in our time hope to make projections regarding
molecular machines as accurate as those Leonardo da Vinci made
regarding metal machines? Can we avoid errors like those in his
plans for flying machines? Leonardo's example suggests that we can. It
may help to remember that Leonardo himself probably lacked
confidence in his aircraft, and that his errors nonetheless held a
germ of truth. He was right to believe that flying machines of some
sort were possible- indeed, he could be certain of it because they
already existed. Birds, bats, and bees proved the possibility of
flight. Further, though there were no working examples of his ball
bearings, gears, and chain drives, he could have confidence in their
principles. Able minds had already built a broad foundation of
knowledge about geometry and the laws of leverage. The required
strength and accuracy of the parts may have caused him doubt, but
not their interplay of function and motion.*(58) Leonardo could
propose machines requiring better parts than any then known, and still
have a measure of confidence in his designs.
Proposed molecular technologies likewise rest on a broad
foundation of knowledge, not only of geometry and leverage, but of
chemical bonding, statistical mechanics, and physics in general.
This time, though, the problems of material properties and fabrication
accuracy do not arise in any separate way. The properties of atoms and
bonds are the material properties, and atoms come prefabricated and
perfectly standardized. Thus we now seem better prepared for foresight
than were people in Leonardo's time: we know more about molecules
and controlled bonding than they knew about steel and precision
machining. In addition, we can point to nanomachines that already
exist in the cell as Leonardo could point to the machines (birds)
already flying in the sky.
Projecting how second-generation nanomachines can be built by
protein machines is surely easier than it was to project how precise
steel machines would be built starting with the cruder machines of
Leonardo's time. Learning to use crude machines to make more precise
machines was bound to take time, and the methods were far from
obvious. Molecular machines, in contrast, will be built from identical
prefabricated atomic parts which need only be assembled. Making
precise machines with crooked machines must have been harder to
imagine then than molecular assembly is now. And besides, we know that
molecular assembly happens all the time in nature. Again, we have
firmer grounds for confidence than Leonardo did.
In Leonardo's time, people had scant knowledge of electricity and
magnetism, and knew nothing of molecules and quantum mechanics.
Accordingly, electric lights, radios, and computers would have baffled
them. Today, however, the basic laws most important to engineering-
those describing normal matter- seem well understood. As with
surviving theories of gravity, the scientific engine of disproof has
forced surviving theories of matter into close agreement.
Such knowledge is recent. Before this century people did not
understand why solids were solid or why the Sun shone. Scientists
did not understand the laws that governed matter in the ordinary world
of molecules, people, planets, and stars. This is why our century
has sprouted transistors and hydrogen bombs, and why molecular
technology draws near. This knowledge brings new hopes and dangers,
but at least it gives us the means to see ahead and to prepare.
When the basic laws of a technology are known, future
possibilities can be foreseen (though with gaps, or Leonardo would
have foreseen mechanical computers). Even when the basic laws are
poorly known, as were the principles of aerodynamics in Leonardo's
time, nature can demonstrate possibilities. Finally, when both science
and nature point to a possibility, these lessons suggest that we
take it to heart and plan accordingly.
-
THE ASSEMBLER BREAKTHROUGH
-
The foundations of science may evolve and shift, yet they will
continue to support a steady, growing edifice of engineering know-how.
Eventually, assemblers will allow engineers to make whatever can be
designed, sidestepping the traditional problems of materials and
fabrication. Already, approximations and computer models allow
engineers to evolve designs even in the absence of the tools*(59)
required to implement them. All this will combine to permit foresight-
and something more.
As nanotechnology advances, there will come a time when assemblers
become an imminent prospect, backed by an earnest and well-funded
development program. Their expected capabilities will have become
clear.
By then, computer-aided design of molecular systems*(60)- which
has already begun- will have grown common and sophisticated, spurred
by advances in computer technology and the growing needs of
molecular engineers. Using these design tools, engineers will be
able to design second-generation nanosystems, including the
second-generation assemblers needed to build them. What is more, by
allowing enough margin for inaccuracies (and by preparing
alternative designs), engineers will be able to design many systems
that will work when first built- they will have evolved sound
designs in a world of simulated molecules.
Consider the force of this situation: under development will be
the greatest production tool in history, a truly general fabrication
system able to make anything that can be designed- and a design system
will already be in hand. Will everyone wait until assemblers appear
before planning how to use them? Or will companies and countries
respond to the pressures of opportunity and competition by designing
nanosystems in advance, to speed the exploitation of assemblers when
they first arrive?
This design-ahead*(61) process seems sure to occur; the only
question is when it will start and how far it will go. Years of
quiet design progress may well erupt into hardware with
unprecedented suddenness in the wake of the assembler breakthrough.
How well we design ahead- and what we design- may determine whether we
survive and thrive, or whether we obliterate ourselves.
Because the assembler breakthrough will affect almost the whole of
technology, foresight is an enormous task. Of the universe of possible
mechanical devices, Leonardo foresaw only a few. Similarly, of the far
broader universe of future technologies, modern minds can foresee only
a few. A few advances, however, seem of basic importance.
Medical technology, the space frontier, advanced computers, and
new social inventions all promise to play interlocking roles. But
the assembler breakthrough will affect all of them, and more.
PART TWO
Profiles of the Possible
-
4
Engines of Abundance
-
If every tool, when ordered,*(62) or even of its own accord, could
do the work that befits it... then there would be no need either of
apprentices for the master workers or of slaves for the lords.
-ARISTOTLE
-
ON MARCH 27, 1981, CBS radio news quoted a NASA scientist*(63) as
saying that engineers will be able to build self-replicating robots
within twenty years, for use in space or on Earth. These machines
would build copies of themselves, and the copies would be directed
to make useful products. He had no doubt of their possibility, only of
when they will be built. He was quite right.
Since 1951, when John von Neumann outlined the principles of
self-replicating machines, scientists have generally acknowledged
their possibility. In 1953 Watson and Crick described the structure of
DNA, which showed how living things pass on the instructions that
guide their construction. Biologists have since learned in
increasing detail how the self-replicating molecular machinery of
the cell works. They find that it follows the principles von Neumann
had outlined. As birds prove the possibility of flight, so life in
general proves the possibility of self-replication, at least by
systems of molecular machines. The NASA scientist, however, had
something else in mind.
-
CLANKING REPLICATORS
-
Biological replicators, such as viruses, bacteria,*(64) plants,
and people, use molecular machines. Artificial replicators can use
bulk technology instead. Since we have bulk technology today,
engineers may use it to build replicators before molecular
technology arrives.
The ancient myth of a magical life-force (coupled with the
misconception that the increase of entropy means that everything in
the universe must constantly run down) has spawned a meme saying
that replicators must violate some natural law. This simply isn't
so. Biochemists understand how cells replicate and they find no
magic in them. Instead, they find machines supplied with all the
materials, energy, and instructions needed to do the job. Cells do
replicate; robots could replicate.
Advances in automation will lead naturally toward mechanical
replicators, whether or not anyone makes them a specific goal. As
competitive pressures force increased automation, the need for human
labor in factories will shrink. Fujitsu Fanuc*(65) already runs the
machining section in a manufacturing plant twenty-four hours a day
with only nineteen workers on the floor during the day shift, and none
on the floor during the night shift. This factory produces 250
machines a month, of which 100 are robots.
Eventually, robots could do all the robot-assembly work, assemble
other equipment, make the needed parts, run the mines and generators
that supply the various factories with materials and power, and so
forth. Though such a network of factories spread across the
landscape wouldn't resemble a pregnant robot, it would form a
self-expanding, self-replicating system. The assembler breakthrough
will surely arrive before the complete automation of industry, yet
modern moves in this direction are moves toward a sort of gigantic,
clanking replicator.
But how can such a system be maintained and repaired without human
labor?
Imagine an automatic factory able to both test parts and assemble
equipment. Bad parts fail the tests and are thrown out or recycled. If
the factory can also take machines apart, repairs are easy: simply
disassemble the faulty machines, test all their parts, replace any
worn or broken parts, and reassemble them. A more efficient system
would diagnose problems without testing every part, but this isn't
strictly necessary.
A sprawling system of factories staffed by robots would be
workable but cumbersome. Using clever design and a minimum of
different parts and materials, engineers could fit a replicating
system into a single box- but the box might still be huge, because
it must contain equipment able to make and assemble many different
parts. How many different parts? As many as it itself contains. How
many different parts and materials would be needed to build a
machine able to make and assemble so many different materials and
parts? This is hard to estimate, but systems based on today's
technology would use electronic chips. Making these alone would
require too much equipment to stuff into the belly of a small
replicator.
Rabbits replicate, but they require prefabricated parts such as
vitamin molecules. Getting these from food lets them survive with less
molecular machinery than they would need to make everything from
scratch. Similarly, a mechanical replicator using prefabricated
chips could be made somewhat simpler than one that made everything
it needed. Its peculiar "dietary" requirements would also tie it to
a wider "ecology" of machines, helping to keep it on a firm leash.
Engineers in NASA-sponsored studies have proposed using such
semireplicators in space, allowing space industry to expand with
only a small input of sophisticated parts from Earth.
Still, since bulk-technology replicators must make and assemble
their parts, they must contain both part-making and part-assembling
machines. This highlights an advantage of molecular replicators: their
parts are atoms, and atoms come ready-made.
-
MOLECULAR REPLICATORS
-
Cells replicate. Their machines copy their DNA, which directs
their ribosomal machinery to build other machines from simpler
molecules. These machines and molecules are held in a fluid-filled
bag. Its membrane lets in fuel molecules and parts for more
nanomachines, DNA, membrane, and so forth; it lets out spent fuel
and scrapped components. A cell replicates by copying the parts inside
its membrane bag, sorting them into two clumps, and then pinching
the bag in two. Artificial replicators could be built to work in a
similar way, but using assemblers instead of ribosomes. In this way,
we could build cell-like replicators that are not limited to molecular
machinery made from the soft, moist folds of protein molecules.
But engineers seem more likely to develop other approaches to
replication. Evolution had no easy way to alter the fundamental
pattern of the cell, and this pattern has shortcomings. In synapses,
for example, the cells of the brain signal their neighbors by emptying
bladders of chemical molecules. The molecules then jostle around until
they bind to sensor molecules on the neighboring cell, sometimes
triggering a neural impulse. A chemical synapse makes a slow switch,
and neural impulses move slower than sound. With assemblers, molecular
engineers will build entire computers smaller than a synapse and a
millionfold faster.
Mutation and selection could no more make a synapse into a
mechanical nanocomputer than a breeder could make a horse into a
car. Nonetheless, engineers have built cars, and will also learn to
build computers faster than brains, and replicators more capable
than existing cells.
Some of these replicators will not resemble cells at all, but will
instead resemble factories*(66) shrunk to cellular size. They will
contain nanomachines mounted on a molecular framework and conveyor
belts to move parts from machine to machine. Outside, they will have a
set of assembler arms for building replicas of themselves, an atom
or a section at a time.
How fast these replicators can replicate will depend on their
assembly speed and their size. Imagine an advanced assembler that
contains a million atoms: it can have as many as ten thousand moving
parts, each containing an average of one hundred atoms- enough parts
to make up a rather complex machine. In fact, the assembler itself
looks like a box supporting a stubby robot arm a hundred atoms long.
The box and arm contain devices that move the arm from position to
position, and others that change the molecular tools at its tip.
Behind the box sits a device that reads a tape and provides
mechanical signals that trigger arm motions and tool changes. In front
of the arm sits an unfinished structure. Conveyors bring molecules
to the assembler system. Some supply energy to motors that drive the
tape reader and arm, and others supply groups of atoms for assembly.
Atom by atom (or group by group), the arm moves pieces into place as
directed by the tape; chemical reactions bond them to the structure on
contact.
These assemblers will work fast. A fast enzyme,*(67) such as
carbonic anhydrase or ketosteroid isomerase, can process almost a
million molecules per second, even without conveyors and
power-driven mechanisms to slap a new molecule into place as soon as
an old one is released. It might seem too much to expect an
assembler to grab a molecule, move it, and jam it into place in a mere
millionth of a second. But small appendages can move to and fro very
swiftly. A human arm can flap up and down several times per second,
fingers can tap more rapidly, a fly can wave its wings fast enough
to buzz, and a mosquito makes a maddening whine. Insects can wave
their wings at about a thousand times the frequency of a human arm
because an insect's wing is about a thousand times shorter.
An assembler arm will be about fifty million times shorter than a
human arm, and so (as it turns out) it will be able to move back and
forth about fifty million times more rapidly.*(68) For an assembler
arm to move a mere million times per second would be like a human
arm moving about once per minute: sluggish. So it seems a very
reasonable goal.
The speed of replication will depend also on the total size of the
system to be built. Assemblers will not replicate by themselves;
they will need materials and energy, and instructions on how to use
them. Ordinary chemicals can supply materials and energy, but
nanomachinery must be available to process them. Bumpy polymer
molecules can code information like a punched paper tape, but a reader
must be available to translate the patterns of bumps into patterns
of arm motion. Together, these parts form the essentials of a
replicator: the tape supplies instructions for assembling a copy of
the assembler, of the reader, of the other nanomachines, and of the
tape*(69) itself.
A reasonable design for this sort of replicator will likely
include several assembler arms and several more arms to hold and
move workpieces. Each of these arms will add another million atoms
or so. The other parts- tape readers, chemical processors, and so
forth- may also be as complicated as assemblers. Finally, a flexible
replicator system will probably include a simple computer; following
the mechanical approach that I mentioned in Chapter 1, this will add
roughly 100 million atoms. Altogether, these parts will total less
than 150 million atoms. Assume instead a total of one billion, to
leave a wide margin for error. Ignore the added capability of the
additional assembler arms, leaving a still wider margin. Working at
one million atoms per second, the system will still copy itself in one
thousand seconds, or a bit over fifteen minutes- about the time a
bacterium takes to replicate under good conditions.
Imagine such a replicator floating in a bottle of chemicals,
making copies of itself. It builds one copy in one thousand seconds,
thirty-six in ten hours. In a week, it stacks up enough copies to fill
the volume of a human cell. In a century, it stacks up enough to
make a respectable speck. If this were all that replicators could
do, we could perhaps ignore them in safety.
Each copy, though, will build yet more copies. Thus the first
replicator assembles a copy in one thousand seconds, the two
replicators then build two more in the next thousand seconds, the four
build another four, and the eight build another eight. At the end of
ten hours, there are not thirty-six new replicators, but over 68
billion. In less than a day, they would weigh a ton; in less than
two days, they would outweigh the Earth; in another four hours, they
would exceed the mass of the Sun and all the planets combined- if
the bottle of chemicals hadn't run dry long before.
Regular doubling means exponential growth. Replicators multiply
exponentially unless restrained, as by lack of room or resources.
Bacteria do it, and at about the same rate as the replicators just
described. People replicate far more slowly, yet given time enough
they, too, could overshoot any finite resource supply. Concern about
population growth will never lose its importance. Concern about
controlling rapid new replicators will soon become important indeed.
-
MOLECULES AND SKYSCRAPERS
-
Machines able to grasp and position individual atoms will be able to
build almost anything by bonding the right atoms together in the right
patterns, as I described at the end of Chapter 1. To be sure, building
large objects one atom at a time will be slow. A fly, after all,
contains about a million atoms for every second since the dinosaurs
were young. Molecular machines can nonetheless build objects of
substantial size- they build whales, after all.
To make large objects rapidly, a vast number of assemblers must
cooperate, but replicators will produce assemblers by the ton. Indeed,
with correct design, the difference between an assembler system and
a replicator will lie entirely in the assembler's programming. If a
replicating assembler can copy itself in one thousand seconds, then it
can be programmed to build something else its own size just as fast.
Similarly, a ton of replicators can swiftly build a ton of something
else- and the product will have all its billions of billions of
billions of atoms in the right place, with only a minute fraction
misplaced.*(70)
To see the abilities and limits of one method for assembling large
objects, imagine a flat sheet covered with small assembly arms-
perhaps an army of replicators reprogrammed for construction work
and arrayed in orderly ranks. Conveyors and communication channels
behind them supply reactive molecules, energy, and assembly
instructions. If each arm occupies an area 100 atomic diameters
wide, then behind each assembler will be room for conveyors and
channels totaling about 10,000 atoms in cross-sectional area.
This seems room enough. A space ten or twenty atoms wide can hold
a conveyor (perhaps based on molecular belts and pulleys). A channel a
few atoms wide can hold a molecular rod which, like those in the
mechanical computer mentioned in Chapter 1, will be pushed and
pulled to transmit signals. All the arms will work together to build a
broad, solid structure layer by layer. Each arm will be responsible
for its own area, handling about 10,000 atoms per layer. A sheet of
assemblers handling 1,000,000 atoms per second per arm will complete
about one hundred atomic layers per second. This may sound fast, but
at this rate piling up a paper-sheet thickness will take about an
hour, and making a meter-thick slab will take over a year.
Faster arms might raise the assembly speed to over a meter per
day, but they would produce more waste heat. If they could build a
meter-thick layer in a day, the heat from one square meter could
cook hundreds of steaks simultaneously, and might fry the machinery.
At some size and speed, cooling problems will become a limiting
factor, but there are other ways of assembling objects faster
without overheating the machinery.
Imagine trying to build a house by gluing together individual grains
of sand. Adding a layer of grains might take grain-gluing machines
so long that raising the walls would take decades. Now imagine that
machines in a factory first glue the grains together to make bricks.
The factory can work on many bricks at once. With enough
grain-gluing machines, bricks would pour out fast; wall assemblers
could then build walls swiftly by stacking the preassembled bricks.
Similarly, molecular assemblers will team up with larger assemblers to
build big things quickly- machines can be any size from molecular to
gigantic. With this approach, most of the assembly heat will be
dissipated far from the work site, in making the parts.
Skyscraper construction and the architecture of life suggest a
related way to construct large objects. Large plants and animals
have vascular systems, intricate channels that carry materials to
molecular machinery working throughout their tissues. Similarly, after
riggers and riveters finish the frame of a skyscraper, the
building's "vascular system"- its elevators and corridors, aided by
cranes- carry construction materials to workers throughout the
interior. Assembly systems could also employ this strategy, first
putting up a scaffold and then working throughout its volume,
incorporating materials brought through channels from the outside.
Imagine this approach being used to "grow" a large rocket engine,
working inside a vat in an industrial plant. The vat- made of shiny
steel, with a glass window for the benefit of visitors- stands
taller than a person, since it must hold the completed engine. Pipes
and pumps link it to other equipment and to water-cooled heat
exchangers. This arrangement lets the operator circulate various
fluids through the vat.
To begin the process, the operator swings back the top of the vat
and lowers into it a base plate on which the engine will be built. The
top is then resealed. At the touch of a button, pumps flood the
chamber with a thick, milky fluid which submerges the plate and then
obscures the window. This fluid flows from another vat in which
replicating assemblers have been raised and then reprogrammed by
making them copy and spread a new instruction tape (a bit like
infecting bacteria with a virus). These new assembler systems, smaller
than bacteria, scatter light and make the fluid look milky. Their
sheer abundance makes it viscous.
At the center of the base plate, deep in the swirling,
assembler-laden fluid, sits a "seed." It contains a nanocomputer
with stored engine plans, and its surface sports patches to which
assemblers stick. When an assembler sticks to it, they plug themselves
together and the seed computer transfers instructions to the assembler
computer. This new programming tells it where it is in relation to the
seed, and directs it to extend its manipulator arms to snag more
assemblers. These then plug in and are similarly programmed. Obeying
these instructions from the seed (which spread through the expanding
network of communicating assemblers) a sort of assembler-crystal grows
from the chaos of the liquid. Since each assembler knows its
location in the plan, it snags more assemblers only where more are
needed. This forms a pattern less regular and more complex than that
of any natural crystal. In the course of a few hours, the assembler
scaffolding grows to match the final shape of the planned rocket
engine.
Then the vat's pumps return to life, replacing the milky fluid of
unattached assemblers with a clear mixture of organic solvents and
dissolved substances- including aluminum compounds, oxygen-rich
compounds, and compounds to serve as assembler fuel. As the fluid
clears, the shape of the rocket engine grows visible through the
window, looking like a full-scale model sculpted in translucent
white plastic. Next, a message spreading from the seed directs
designated assemblers to release their neighbors and fold their
arms. They wash out of the structure in sudden streamers of white,
leaving a spongy lattice of attached assemblers, now with room
enough to work. The engine shape in the vat grows almost
transparent, with a hint of iridescence.
Each remaining assembler, though still linked to its neighbors, is
now surrounded by tiny fluid-filled channels. Special arms on the
assemblers work like flagella, whipping the fluid along to circulate
it through the channels. These motions, like all the others
performed by the assemblers, are powered by molecular engines fueled
by molecules in the fluid. As dissolved sugar powers yeast, so these
dissolved chemicals power assemblers. The flowing fluid brings fresh
fuel and dissolved raw materials for construction; as it flows out
it carries off waste heat. The communications network spreads
instructions to each assembler.
The assemblers are now ready to start construction. They are to
build a rocket engine, consisting mostly of pipes and pumps. This
means building strong, light structures in intricate shapes, some able
to stand intense heat, some full of tubes to carry cooling fluid.
Where great strength is needed, the assemblers set to work
constructing rods of interlocked fibers of carbon, in its diamond
form. From these, they build a lattice tailored to stand up to the
expected pattern of stress. Where resistance to heat and corrosion
is essential (as on many surfaces), they build similar structures of
aluminum oxide, in its sapphire form. In places where stress will be
low, the assemblers save mass by leaving wider spaces in the
lattice. In places where stress will be high, the assemblers reinforce
the structure until the remaining passages are barely wide enough
for the assemblers to move. Elsewhere the assemblers lay down other
materials to make sensors, computers, motors, solenoids, and
whatever else is needed.
To finish their jobs, they build walls to divide the remaining
channel spaces into almost sealed cells, then withdraw to the last
openings and pump out the fluid inside. Sealing the empty cells,
they withdraw completely and float away in the circulating fluid.
Finally, the vat drains, a spray rinses the engine, the lid lifts, and
the finished engine is hoisted out to dry. Its creation has required
less than a day and almost no human attention.
What is the engine like? Rather than being a massive piece of welded
and bolted metal, it is a seamless thing, gemlike. Its empty
internal cells, patterned in arrays about a wavelength of light apart,
have a side effect: like the pits on a laser disk they diffract light,
producing a varied iridescence like that of a fire opal. These empty
spaces lighten a structure already made from some of the lightest,
strongest materials known. Compared to a modern metal engine, this
advanced engine has over 90 percent less mass.
Tap it, and it rings like a bell of surprisingly high pitch for
its size. Mounted in a spacecraft of similar construction, it flies
from a runway to space and back again with ease. It stands long,
hard use because its strong materials have let designers include large
safety margins. Because assemblers have let designers pattern its
structure to yield before breaking (blunting cracks and halting
their spread), the engine is not only strong but tough.
For all its excellence, this engine is fundamentally quite
conventional. It has merely replaced dense metal with carefully
tailored structures of light, tightly bonded atoms. The final
product contains no nanomachinery.
More advanced designs will exploit nanotechnology more deeply.
They could leave a vascular system in place to supply assembler and
disassembler systems; these can be programmed to mend worn parts. So
long as users supply such an engine with energy and raw materials,
it will renew its own structure. More advanced engines can also be
literally more flexible. Rocket engines work best if they can take
different shapes under different operating conditions, but engineers
cannot make bulk metal strong, light, and limber. With nanotechnology,
though, a structure stronger than steel and lighter than wood could
change shape like muscle (working, like muscle,*(71) on the
sliding-fiber principle). An engine could then expand, contract, and
bend at the base to provide the desired thrust in the desired
direction under varying conditions. With properly programmed
assemblers and disassemblers, it could even remodel its fundamental
structure long after leaving the vat.
-
In short, replicating assemblers will copy themselves by the ton,
then make other products such as computers, rocket engines, chairs,
and so forth. They will make disassemblers able to break down rock
to supply raw material. They will make solar collectors to supply
energy. Though tiny, they will build big. Teams of nanomachines in
nature build whales, and seeds replicate machinery and organize
atoms into vast structures of cellulose, building redwood trees. There
is nothing too startling about growing a rocket engine in a
specially prepared vat. Indeed, foresters given suitable assembler
"seeds" could grow spaceships from soil, air, and sunlight.
Assemblers will be able to make virtually anything from common
materials without labor, replacing smoking factories with systems as
clean as forests. They will transform technology and the economy at
their roots, opening a new world of possibilities. They will indeed be
engines of abundance.
5
Thinking Machines
-
The world stands*(72) on the threshold of a second computer age. New
technology now moving out of the laboratory is starting to change
the computer from a fantastically fast calculating machine to a device
that mimics human thought processes- giving machines the capability to
reason, make judgments, and even learn. Already this "artificial
intelligence" is performing tasks once thought to require human
intelligence...
-Business Week
-
COMPUTERS have emerged from back rooms and laboratories to help with
writing, calculating, and play in homes and offices. These machines do
simple, repetitive tasks, but machines still in the laboratory do much
more. Artificial intelligence researchers say that computers can be
made smart, and fewer and fewer people disagree. To understand our
future, we must see whether artificial intelligence is as impossible
as flying to the Moon.
Thinking machines need not resemble human beings in shape,
purpose, or mental skills. Indeed, some artificial intelligence
systems will show few traits of the intelligent liberal arts graduate,
but will instead serve only as powerful engines of design.
Nonetheless, understanding how human minds evolved from mindless
matter will shed light on how machines can be made to think. Minds,
like other forms of order, evolved through variation and selection.
Minds act. One need not embrace Skinnerian behaviorism to see the
importance of behavior, including the internal behavior called
thinking. RNA replicating in test tubes shows how the idea of
purpose can apply (as a kind of shorthand) to utterly mindless
molecules. They lack nerves and muscles, but they have evolved to
"behave" in ways that promote their replication. Variation and
selection have shaped each molecule's simple behavior, which remains
fixed for its whole "life."
Individual RNA molecules don't adapt, but bacteria do. Competition
has favored bacteria that adapt to change, for example by adjusting
their mix of digestive enzymes to suit the food available. Yet these
mechanisms of adaptation are themselves fixed: food molecules trip
genetic switches as cold air trips a thermostat.
Some bacteria also use a primitive form of trial-and-error guidance.
Bacteria of this sort tend to swim in straight lines, and have just
enough "memory" to know whether conditions are improving or
worsening as they go. If they sense that conditions are improving,
they keep going straight. If they sense that conditions are getting
worse, they stop, tumble, and head off in a random, generally
different, direction. They test directions, and favor the good
directions by discarding the bad. And because this makes them wander
toward concentrations of food molecules, they have prospered.
Flatworms lack brains, yet show the faculty of true learning. They
can learn to choose the correct path in a simple T-maze. They try
turning left and turning right, and gradually select the behavior-
or form the habit- which produces the better result. This is selection
of behavior by its consequences, which behaviorist psychologists
call "the Law of Effect." The evolving genes of worm species have
produced worm individuals with evolving behavior.
Still, worms trained to run mazes (even Skinner's pigeons, trained
to peck when a light flashes green) show no sign of the reflective
thought we associate with mind. Organisms adapting only though the
simple Law of Effect learn only by trial and error, by varying and
selecting actual behavior- they don't think ahead and decide. Yet
natural selection often favored organisms that could think, and
thinking is not magical. As Daniel Dennett of Tufts University
points out,*(73) evolved genes can equip animal brains with internal
models of how the world works (somewhat like the models in
computer-aided engineering systems). The animals can then "imagine"
various actions and consequences, avoiding actions which "seem"
dangerous and carrying out actions which "seem" safe and profitable.
By testing ideas against these internal models, they can save the
effort and risk of testing actions in the external world.
Dennett further points out that the Law of Effect can reshape the
models themselves. As genes can provide for evolving behavior, so they
can provide for evolving mental models. Flexible organisms can vary
their models and pay more attention to the versions that prove
better guides to action. We all know what it is to try things, and
learn which work. Models need not be instinctive; they can evolve in
the course of a single life.
Speechless animals, however, seldom pass on their new insights.
These vanish with the brain that first produced them, because
learned mental models are not stamped into the genes. Yet even
speechless animals can imitate each other, giving rise to memes and
cultures. A female monkey in Japan invented a way to use water to
separate grain from sand; others quickly learned to do the same. In
human cultures, with their language and pictures, valuable new
models of how the world works can outlast their creators and spread
worldwide.
On a still higher level, a mind (and "mind" is by now a fitting
name) can hold evolving standards for judging whether the parts of a
model- the ideas of a worldview- seem reliable enough to guide action.
The mind thus selects its own contents, including its selection rules.
The rules of judgment that filter the contents of science evolved in
this way.
As behavior, models, and standards for knowledge evolve, so can
goals. That which brings good, as judged by some more basic
standard, eventually begins to seem good: it then becomes a goal in
itself. Honesty pays, and becomes a valued principle of action. As
thought and mental models guide action and further thought, we adopt
clear thinking and accurate models as goals in themselves. Curiosity
grows, and with it a love of knowledge for its own sake. The evolution
of goals thus brings forth both science and ethics. As Charles
Darwin wrote, "the highest possible stage in moral culture is when
we recognize that we ought to control our thoughts." We achieve this
as well by variation and selection, by concentrating on thoughts of
value and letting others slip from attention.
Marvin Minsky of the MIT Artificial Intelligence Laboratory views
the mind*(74) as a sort of society, an evolving system of
communicating, cooperating, competing agencies, each made up of yet
simpler agents. He describes thinking and action in terms of the
activity of these agencies. Some agencies can do little more than
guide a hand to grasp a cup; others (vastly more elaborate) guide
the speech system as it chooses words in a sticky situation. We aren't
aware of directing our fingers to wrap around a cup just so. We
delegate such tasks to competent agents and seldom notice unless
they slip. We all feel conflicting impulses and speak unintended
words; these are symptoms of discord among the agents of the mind. Our
awareness of this is part of the self-regulating process by which
our most general agencies manage the rest.
Memes may be seen as agents in the mind that are formed by
teaching and imitation. To feel that two ideas conflict, you must have
embodied both of them as agents in your mind- though one may be old,
strong, and supported by allies, and the other a fresh idea-agent that
may not survive its first battle. Because of our superficial
self-awareness, we often wonder where an idea in our heads came
from. Some people imagine that these thoughts and feelings come
directly from agencies outside their own minds; they incline toward
a belief in haunted heads.
In ancient Rome, people believed in "genii," in good and evil
spirits attending a person from cradle to grave, bringing good and ill
luck. They attributed outstanding success to a special "genius." And
even now, people who fail to see how natural processes create
novelty see "genius" as a form of magic. But in fact, evolving genes
have made minds that expand their knowledge by varying idea patterns
and selecting among them. With quick variation and effective
selection, guided by knowledge borrowed from others, why shouldn't
such minds show what we call genius? Seeing intelligence as a
natural process makes the idea of intelligent machines less startling.
It also suggests how they might work.
-
MACHINE INTELLIGENCE
-
One dictionary definition of "machine" is "Any system or
device,*(75) such as an electronic computer, that performs or
assists in the performance of a human task." But just how many human
tasks will machines be able to perform? Calculation was once a
mental skill beyond machines, the province of the intelligent and
educated. Today, no one thinks of calling a pocket calculator an
artificial intelligence; calculation now seems a "merely" mechanical
procedure.
Still, the idea of building ordinary computers once was shocking. By
the mid 1800s, though, Charles Babbage had built*(76) mechanical
calculators and part of a programmable mechanical computer; however,
he ran into difficulties of finance and construction. One Dr. Young
helped not at all: he argued that it would be cheaper to invest the
money and use the interest to pay human calculators. Nor did the
British Astronomer Royal, Sir George Airy- an entry in his diary
states that "On September 15th Mr. Goulburn... asked my opinion on the
utility of Babbage's calculating machine... I replied, entering
fully into the matter, and giving my opinion that it was worthless."
Babbage's machine was ahead of its time- meaning that in building
it, machinists were forced to advance the art of making precision
parts. And in fact it would not have greatly exceeded the speed of a
skilled human calculator- but it would have been more reliable and
easier to improve.
The story of computers and artificial intelligence, (known as AI)
resembles that of flight in air and space. Until recently people
dismissed both ideas as impossible- commonly meaning that they
couldn't see how to do them, or would be upset if they could. And so
far, AI has had no simple, clinching demonstration, no equivalent of a
working airplane or a landing on the Moon. It has come a long way, but
people keep changing their definitions of intelligence.
Press reports of "giant electronic brains" aside, few people
called the first computers intelligent. Indeed, the very name
"computer" suggests a mere arithmetic machine. Yet in 1956, at
Dartmouth, during the world's first conference on artificial
intelligence, researchers Alan Newell and Herbert Simon unveiled Logic
Theorist, a program that proved theorems in symbolic logic. In later
years computer programs were playing chess and helping chemists
determine molecular structures. Two medical programs, CASNET and MYCIN
(the first dealing with internal medicine, the other with the
diagnosis and treatment of infections), have performed impressively.
According to the Handbook of Artificial Intelligence,*(77) they have
been "rated, in experimental evaluations, as performing at
human-expert levels in their respective domains." A program called
PROSPECTOR has located, in Washington state, a molybdenum deposit
worth millions of dollars.
These so-called "expert systems" succeed only within strictly
limited areas of competence, but they would have amazed the computer
programmers of the early 1950s. Today, however, few people consider
them to be real artificial intelligence: AI has been a moving
target. The passage from Business Week quoted earlier only shows
that computers can now be programmed with enough knowledge, and
perform fancy enough tricks, that some people feel comfortable calling
them intelligent. Years of seeing fictional robots and talking
computers on television have at least made the idea of AI familiar.
The chief reason for declaring AI impossible has always been the
notion that "machines" are intrinsically stupid, an idea that is now
beginning to fade. Past machines have indeed been gross, clumsy things
that did simple, brute-force work. But computers handle information,
follow complex instructions, and can be instructed to change their own
instructions. They can experiment and learn. They contain not gears
and grease but traceries of wire and evanescent patterns of electrical
energy. As Douglas Hofstadter urges*(78) (through a character in a
dialogue about AI), "Why don't you let the word 'machine' conjure up
images of patterns of dancing light rather than of giant steam
shovels?"
Cocktail-party critics confronted with the idea of artificial
intelligence often point to the stupidity of present computers, as
if this proved something about the future. (A future machine may
wonder whether such critics exhibited genuine thought.) Their
objection is irrelevant- steam locomotives didn't fly, though they
demonstrated mechanical principles later used in airplane engines.
Likewise, the creeping worms of an eon ago showed no noticeable
intelligence, yet our brains use neurons much like theirs.
Casual critics also avoid thinking seriously about AI by declaring
that we can't possibly build machines smarter than ourselves. They
forget what history shows. Our distant, speechless ancestors managed
to bring forth entities of greater intelligence through genetic
evolution without even thinking about it. But we are thinking about
it, and the memes of technology evolve far more swiftly than the genes
of biology. We can surely make machines*(79) with a more human-like
ability to learn and organize knowledge.
There seems to be only one idea that could argue for the
impossibility of making thought patterns dance in new forms of matter.
This is the idea of mental materialism- the concept that mind is a
special substance, a magical thinking-stuff somehow beyond
imitation, duplication, or technological use.
Psychobiologists see no evidence for such a substance, and find no
need for mental materialism to explain the mind. Because the
complexity of the brain lies beyond the full grasp of human
understanding, it seems complex enough to embody a mind. Indeed, if
a single person could fully understand a brain, this would make the
brain less complex than that person's mind. If all Earth's billions of
people could cooperate in simply watching the activity of one human
brain, each person would have to monitor tens of thousands of active
synapses simultaneously- clearly an impossible task. For a person to
try to understand the flickering patterns of the brain as a whole
would be five billion times more absurd. Since our brain's mechanism
so massively overwhelms our mind's ability to grasp it, that mechanism
seems complex enough to embody the mind itself.
-
TURING'S TARGET
-
In a 1950 paper on machine intelligence, British mathematician
Alan Turing wrote: "I believe that by the end of the century*(80)
the use of words and general educated opinion will have altered so
much that one will be able to speak of machines thinking without
expecting to be contradicted." But this will depend on what we call
thinking. Some say that only people can think, and that computers
cannot be people; they then sit back and look smug.
But in his paper, Turing asked how we judge human intelligence,
and suggested that we commonly judge people by the quality of their
conversation. He then proposed what he called the imitation game-
which everyone else now calls the Turing test. Imagine that you are in
a room, able to communicate through a terminal with a person and a
computer in two other rooms. You type messages; both the person and
the computer can reply. Each tries to act human and intelligent. After
a prolonged keyboard "conversation" with them- perhaps touching on
literature, art, the weather, and how a mouth tastes in the morning-
it might be that you could not tell which was the person and which the
machine. If a machine could converse this well on a regular basis,
then Turing suggests that we should consider it genuinely intelligent.
Further, we would have to acknowledge that it knew a great deal
about human beings.
For most practical purposes, we need not ask "Can a machine have
self-awareness- that is, consciousness?" Indeed, critics who declare
that machines cannot be conscious never seem able to say quite what
they mean by the term. Self-awareness evolved to guide thought and
action, not merely to ornament our humanity. We must be aware of other
people, and of their abilities and inclinations, to make plans that
involve them. Likewise we must be aware of ourselves, and of our own
abilities and inclinations, to make plans about ourselves. There is no
special mystery in self-awareness. What we call the self reacts to
impressions from the rest of the mind, orchestrating some of its
activities; this makes it no more (and no less) than a special part of
the interacting patterns of thought. The idea that the self is a
pattern in a special mind substance (distinct from the mind
substance of the brain) would explain nothing about awareness.
A machine attempting to pass the Turing test would, of course, claim
to have self-awareness. Hard-core biochauvinists would simply say that
it was lying or confused. So long as they refuse to say what they mean
by consciousness, they can never be proved wrong. Nonetheless, whether
called conscious or not, intelligent machines will still act
intelligent, and it is their actions that will affect us. Perhaps they
will someday shame the biochauvinists into silence by impassioned
argument, aided by a brilliant public-relations campaign.
No machine can now pass the Turing test, and none is likely to do so
soon. It seems wise to ask whether there is a good reason even to try:
we may gain more from AI research guided by other goals.
Let us distinguish two sorts of artificial intelligence, though a
system could show both kinds.*(81) The first is technical AI,
adapted to deal with the physical world. Efforts in this field lead
toward automated engineering and scientific inquiry. The second is
social AI, adapted to deal with human minds. Efforts in this field
lead toward machines able to pass the Turing test.
Researchers working on social AI*(82) systems will learn much
about the human mind along the way, and their systems will doubtless
have great practical value, since we all can profit from intelligent
help and advice. But automated engineering based on technical AI
will have a greater impact on the technology race, including the
race toward molecular technology. And an advanced automated
engineering system may be easier to develop than a Turing-test passer,
which must not only possess knowledge and intelligence, but must mimic
human knowledge and human intelligence- a special, more difficult
challenge.
As Turing asked, "May not machines carry out*(83) something which
ought to be described as thinking but which is very different from
what a man does?" Although some writers and politicians may refuse
to recognize machine intelligence until they are confronted with a
talkative machine able to pass the Turing test, many engineers will
recognize intelligence in other forms.
-
ENGINES OF DESIGN
-
We are well on the way to automated engineering. Knowledge engineers
have marketed expert systems that help people to deal with practical
problems. Programmers have created computer-aided design systems
that embody knowledge about shapes and motion, stress and strain,
electronic circuits, heat flow, and how machine tools shape metal.
Designers use these systems to augment their mental models, speeding
the evolution of yet unbuilt designs. Together, designers and
computers form intelligent, semiartificial systems.
Engineers can use a wide variety of computer systems to aid their
work. At one end of the spectrum, they use computer screens simply
as drawing boards. Farther along, they use systems able to describe
parts in three dimensions and calculate their response to heat,
stress, current, and so on. Some systems also know about
computer-controlled manufacturing equipment, letting engineers make
simulated tests of instructions that will later direct
computer-controlled machines to make real parts. But the far end of
the spectrum of systems involves using computers not just to record
and test designs, but to generate them.
Programmers have developed their most impressive tools for use in
the computer business itself. Software for chip design is an
example. Integrated circuit chips now contain many thousands of
transistors and wires. Designers once had to work for many months to
design a circuit to do a given job, and to lay out its many parts
across the surface of the chip. Today they can often delegate this
task to a so-called "silicon compiler." Given a specification of a
chip's function, these software systems can produce a detailed design-
ready for manufacture- with little or no human help.
All these systems rely entirely on human knowledge, laboriously
gathered and coded. The most flexible automated design systems today
can fiddle with a proposed design to seek improvements, but they learn
nothing applicable to the next design. But EURISKO is different.
Developed by Professor Douglas Lenat*(84) and others at Stanford
University, EURISKO is designed to explore new areas of knowledge.
It is guided by heuristics- pieces of knowledge that suggest plausible
actions to follow or implausible ones to avoid; in effect, various
rules of thumb. It uses heuristics to suggest topics to work on, and
further heuristics to suggest what approaches to try and how to
judge the results. Other heuristics look for patterns in results,
propose new heuristics, and rate the value of both new and old
heuristics. In this way EURISKO evolves better behaviors, better
internal models, and better rules for selecting among internal models.
Lenat himself describes the variation and selection of heuristics
and concepts in the system in terms of "mutation" and "selection," and
suggests a social, cultural metaphor for understanding their
interaction.
Since heuristics evolve and compete in EURISKO, it makes sense to
expect parasites to appear- as indeed many have. One machine-generated
heuristic, for example, rose to the highest possible value rating by
claiming to have been a co-discoverer of every valuable new
conjecture. Professor Lenat has worked closely with EURISKO, improving
its mental immune system by giving it heuristics for shedding
parasites and avoiding stupid lines of reasoning.
EURISKO has been used to explore elementary mathematics,
programming, biological evolution, games, three-dimensional integrated
circuit design, oil spill cleanup, plumbing, and (of course)
heuristics. In some fields it has startled its designers with novel
ideas, including new electronic devices for the emerging technology of
three-dimensional integrated circuits.
The results of a tournament illustrate the power of a human/AI team.
Traveller TCS*(85) is a futuristic naval war game, played in
accordance with two hundred pages of rules specifying design, cost,
and performance constraints for the fleet ("TCS" stands for
"Trillion Credit Squadron"). Professor Lenat gave EURISKO these rules,
a set of starting heuristics, and a program to simulate a battle
between two fleets. He reports that "it then designed fleet after
fleet, using the simulator as the 'natural selection' mechanism as
it 'evolved' better and better fleet designs." The program would run
all night, designing, testing, and drawing lessons from the results.
In the morning Lenat would cull the designs and help it along. He
credits about 60 percent of the results to himself, and about 40
percent to EURISKO.
Lenat and EURISKO entered the 1981 national Traveller TCS tournament
with a strange-looking fleet. The other contestants laughed at it,
then lost to it. The Lenat/EURISKO fleet won every round, emerging
as the national champion. As Lenat notes, "This win is made more
significant by the fact that no one connected with the program had
ever played this game before the tournament, or seen it played, and
there were no practice rounds."
In 1982 the competition sponsors changed the rules. Lenat and
EURISKO entered a very different fleet. Other contestants again
laughed at it, then lost. Lenat and EURISKO again won the national
championship.
In 1983 the competition sponsors told Lenat that if he entered and
won again, the competition would be canceled. Lenat bowed out.
EURISKO and other AI programs show that computers need not be
limited to boring, repetitive work if they are given the right sort of
programming. They can explore possibilities and turn up novel ideas
that surprise their creators. EURISKO has shortcomings,*(86) yet it
points the way to a style of partnership in which an AI system and a
human expert both contribute knowledge and creativity to a design
process.
In coming years, similar systems will transform engineering.
Engineers will work in a creative partnership with their machines,
using software derived from current computer-aided design systems
for doing simulations, and using evolving, EURISKO-like systems to
suggest designs to simulate. The engineer will sit at a screen to type
in goals for the design process and draw sketches of proposed designs.
The system will respond by refining the designs, testing them, and
displaying proposed alternatives, with explanations, graphs, and
diagrams. The engineer will then make further suggestions and changes,
or respond with a new task, until an entire system of hardware has
been designed and simulated.
As such automated engineering systems improve, they will do more and
more of the work faster and faster. More and more often, the
engineer will simply propose goals and then sort among good
solutions proposed by the machine. Less and less often will the
engineer have to select parts, materials, and configurations.
Gradually engineers will be able to propose more general goals and
expect good solutions to appear as a matter of course. Just as EURISKO
ran for hours evolving fleets with a Traveller TCS simulator,
automated engineering systems will someday work steadily to evolve
passenger jets having maximum safety and economy- or to evolve
military jets and missiles best able to control the skies.
Just as EURISKO has invented electronic devices, future automated
engineering systems will invent molecular machines and molecular
electronic devices, aided by software for molecular simulations.
Such advances in automated engineering will magnify the design-ahead
phenomenon described earlier. Thus automated engineering will not only
speed the assembler breakthrough, it will increase the leap that
follows.
Eventually software systems will be able to create bold new
designs without human help. Will most people call such systems
intelligent? It doesn't really matter.
-
THE AI RACE
-
Companies and governments worldwide support AI work because it
promises commercial and military advantages. The United States has
many university artificial intelligence laboratories and a host of new
companies with names like Machine Intelligence Corporation, Thinking
Machines Corporation, Teknowledge, and Cognitive Systems Incorporated.
In October of 1981 the Japanese Ministry of Trade and Industry
announced a ten-year, $850 million program to develop advanced AI
hardware and software. With this, Japanese researchers plan to develop
systems able to perform a billion logical inferences per second. In
the fall of 1984*(87) the Moscow Academy of Science announced a
similar, five-year, $100 million effort. In October of 1983 the U.S.
Department of Defense announced a five-year, $600 million Strategic
Computing Program; they seek machines able to see, reason,
understand speech, and help manage battles. As Paul Wallich reports in
the IEEE Spectrum,*(88) "Artificial intelligence is considered by most
people to be a cornerstone of next-generation computer technology; all
the efforts in different countries accord it a prominent place in
their list of goals."
Advanced AI will emerge step by step, and each step will pay off
in knowledge and increased ability. As with molecular technology
(and many other technologies), attempts to stop advances in one
city, county, or country will at most let others take the lead. A
miraculous success in stopping visible AI work everywhere would at
most delay it and, as computers grow cheaper, let it mature in secret,
beyond public scrutiny. Only a world state of immense power and
stability could truly stop AI research everywhere and forever- a
"solution" of bloodcurdling danger, in light of past abuses of
merely national power. Advanced AI seems inevitable. If we hope to
form a realistic view of the future, we cannot ignore it.
In a sense, artificial intelligence will be the ultimate tool
because it will help us build all possible tools. Advanced AI
systems could maneuver people out of existence, or they could help
us build a new and better world. Aggressors could use them for
conquest, or foresighted defenders could use them to stabilize
peace. They could even help us control AI itself. The hand that
rocks the AI cradle may well rule the world.
As with assemblers, we will need foresight and careful strategy to
use this new technology safely and well. The issues are complex and
interwoven with everything from the details of molecular technology to
employment and the economy to the philosophical basis of human rights.
The most basic issues, though, involve what AI can do.
-
ARE WE SMART ENOUGH?
-
Despite the example of the evolution of human beings, critics may
still argue that our limited intelligence may somehow prevent us
from programming genuinely intelligent machines. This argument seems
weak, amounting to little more than a claim that because the critic
can't see how to succeed, no one else will ever do better. Still,
few would deny that programming computers to equal human abilities
will indeed require fresh insights into human psychology.*(89)
Though the programming path to AI seems open, our knowledge does not
justify the sort of solid confidence that thoughtful engineers had
(decades before Sputnik) in being able to reach the Moon with rockets,
or that we have today in being able to build assemblers through
protein design. Programming genuine artificial intelligence, though
a form of engineering, will require new science. This places it beyond
firm projection.
We need accurate foresight, though. People clinging to comforting
doubts about AI seem likely to suffer from radically flawed images
of the future. Fortunately, automated engineering escapes some of
the burden of biochauvinist prejudice. Most people are less upset by
the idea of machines designing machines than they are by the idea of
true general-purpose AI systems. Besides, automated engineering has
been shown to work; what remains is to extend it. Still, if more
general systems are likely to emerge, we would be foolish to omit them
from our calculations. Is there a way to sidestep the question of
our ability to design intelligent programs?
In the 1950s, many AI researchers concentrated on simulating brain
functions by simulating neurons. But researchers working on programs
based on words and symbols made swifter progress, and the focus of
AI work shifted accordingly. Nonetheless, the basic idea of neural
simulation remains sound, and molecular technology will make it more
practical. What is more, this approach seems guaranteed to work
because it requires no fundamental new insights into the nature of
thought.
Eventually, neurobiologists will use virus-sized molecular
machines*(90) to study the structure and function of the brain, cell
by cell and molecule by molecule where need be. Although AI
researchers may gain useful insights about the organization of thought
from the resulting advances in brain science, neural simulation can
succeed without such insights. Compilers translate computer programs
from one language to another without understanding how they work.
Photocopiers transfer patterns of words without reading them.
Likewise, researchers will be able to copy the neural patterns of
the brain into another medium without understanding their higher-level
organization.
After learning how neurons work, engineers will be able to design
and build analogous devices*(91) based on advanced nanoelectronics and
nanomachines. These will interact like neurons, but will work
faster. Neurons, though complex, do seem simple enough for a mind to
understand and an engineer to imitate. Indeed, neurobiologists have
learned much about their structure and function, even without
molecular-scale machinery to probe their workings.
With this knowledge, engineers will be able to build fast, capable
AI systems, even without understanding the brain and without clever
programming. They need only study the brain's neural structure and
join artificial neurons to form the same functional pattern. If they
make all the parts right- including the way they mesh to form the
whole- then the whole, too, will be right. "Neural" activity will flow
in the patterns we call thought, but faster, because all the parts
will work faster.
-
ACCELERATING THE TECHNOLOGY RACE
-
Advanced AI systems seem possible and inevitable, but what effect
will they have? No one can answer this in full, but one effect of
automated engineering is clear: it will speed our advance toward the
limits of the possible.
To understand our prospects, we need some idea of how fast
advanced AI systems will think. Modern computers have only a tiny
fraction of the brain's complexity, yet they can already run
programs imitating significant aspects of human behavior. They
differ totally from the brain in their basic style of operation,
though, so direct physical comparison is almost useless. The brain
does a huge number of things at once, but fairly slowly; most modern
computers do only one thing at a time, but with blinding speed.
Still, one can imagine AI hardware built to imitate a brain not only
in function, but in structure. This might result from a
neural-simulation approach, or from the evolution of AI programs to
run on hardware with a brainlike style of organization. Either way, we
can use analogies with the human brain to estimate a minimum speed for
advanced assembler-built AI systems.
Neural synapses respond to signals in thousandths of a second;
experimental electronic switches*(92) respond a hundred million
times faster (and nanoelectronic switches will be faster yet).
Neural signals travel at under one hundred meters per second;
electronic signals travel a million times faster. This crude
comparison of speeds suggests that brainlike electronic devices will
work about a million times faster than brains made of neurons (at a
rate limited by the speed of electronic signals).
This estimate is crude, of course. A neural synapse is more
complex than a switch; it can change its response to signals by
changing its structure. Over time, synapses even form and disappear.
These changes in the fibers and connections of the brain embody the
long-term mental changes we call learning. They have stirred Professor
Robert Jastrow*(93) of Dartmouth to describe the brain as an enchanted
loom, weaving and reweaving its neural patterns throughout life.
To imagine a brainlike device with comparable flexibility, picture
its electronic circuits as surrounded by mechanical nanocomputers
and assemblers, with one per synapse-equivalent "switch." Just as
the molecular machinery of a synapse responds to patterns of neural
activity by modifying the synapse's structure, so the nanocomputers
will respond to patterns of activity by directing the nanomachinery to
modify the switch's structure. With the right programming, and with
communication among the nanocomputers to simulate chemical signals,
such a device should behave almost exactly like a brain.
Despite its complexity, the device will be compact. Nanocomputers
will be smaller than synapses, and assembler-built wires will be
thinner than the brain's axons and dendrites. Thin wires and small
switches will make for compact circuits, and compact circuits will
speed the flow of electronic patterns by shortening the distances
signals must travel. It seems that a structure similar to the brain
will fit in less than a cubic centimeter*(94) (as discussed in the
Notes). Shorter signal paths will then join with faster transmission
to yield a device over ten million times faster than a human brain.
Only cooling problems might limit such machines to slower average
speeds. Imagine a conservative design, a millionfold faster than a
brain and dissipating a millionfold more heat.*(95) The system
consists of an assembler-built block of sapphire the size of a
coffee mug, honeycombed with circuit-lined cooling channels. A
high-pressure water pipe of equal diameter is bolted to its
top,*(96) forcing cooling water through the channels to a similar
drainpipe leaving the bottom. Hefty power cables and bundles of
optical-fiber data channels trail from its sides.
The cables supply fifteen megawatts of electric power. The drainpipe
carries the resulting heat away in a three-ton-per-minute flow of
boiling-hot water. The optical fiber bundles carry as much data as a
million television channels. They bear communications with other AI
systems, with engineering simulators, and with assembler systems
that build designs for final testing. Every ten seconds, the system
gobbles almost two kilowatt-days of electric energy (now worth about a
dollar). Every ten seconds, the system completes as much design work
as a human engineer working eight hours a day for a year (now worth
tens of thousands of dollars). In an hour, it completes the work of
centuries. For all its activity, the system works in a silence
broken only by the rush of cooling water.
This addresses the question of the sheer speed of thought, but
what of its complexity? AI development seems unlikely to pause at
the complexity of a single human mind. As John McCarthy of
Stanford's AI lab points out,*(97) if we can place the equivalent of
one human mind in a metal skull, we can place the equivalent of ten
thousand cooperating minds in a building. (And a large modern power
plant could supply power enough for each to think at least ten
thousand times as fast as a person.) To the idea of fast engineering
intelligences, add the idea of fast engineering teams.
Engineering AI systems will be slowed in their work by the need to
perform experiments, but not so much as one might expect. Engineers
today must perform many experiments because bulk technology is unruly.
Who can say in advance exactly how a new alloy will behave when forged
and then bent ten million times? Tiny cracks weaken metal, but details
of processing determine their nature and effects.
Because assemblers will make objects to precise specifications,
the unpredictabilities of bulk technology will be avoided. Designers
(whether human or AI) will then experiment only when experimentation
is faster or cheaper than calculation, or (more rarely) when basic
knowledge is lacking.
AI systems with access to nanomachines will perform many experiments
rapidly. They will design apparatus in seconds, and replicating
assemblers will build it without the many delays (ordering special
parts, shipping them, and so on) that plague projects today.
Experimental apparatus on the scale of an assembler, nanocomputer,
or living cell will take only minutes to build, and nanomanipulators
will perform a million motions per second. Running a million
ordinary experiments at once will be easy. Thus, despite delays for
experimentation, automated engineering systems will move technology
forward with stunning speed.
From past to future, then, the likely pattern of advancing ability
looks something like this. Across eons of time, life moved forward
in a long, slow advance, paced by genetic evolution. Minds with
language picked up the pace, accelerated by the flexibility of
memes. The invention of the methods of science and technology
further accelerated advances by forcing memes to evolve faster.
Growing wealth, education, and population- and better physical and
intellectual tools- have continued this accelerating trend across
our century.
The automation of engineering will speed the pace still more.
Computer-aided design will improve, helping human engineers to
generate and test ideas ever more quickly. Successors to EURISKO
will shrink design times by suggesting designs and filling in the
details of human innovations. At some point, full-fledged automated
engineering systems will pull ahead on their own.
In parallel, molecular technology will develop and mature, aided
by advances in automated engineering. Then assembler-built AI
systems will bring still swifter automated engineering, evolving
technological ideas at a pace set by systems a million times faster
than a human brain. The rate of technological advance will then
quicken to a great upward leap: in a brief time, many areas of
technology will advance to the limits set by natural law. In those
fields, advance will then halt on a lofty plateau of achievement.
This transformation is a dizzying prospect. Beyond it, if we
survive, lies a world with replicating assemblers, able to make
whatever they are told to make, without need for human labor. Beyond
it, if we survive, lies a world with automated engineering systems
able to direct assemblers to make devices near the limits of the
possible, near the final limits of technical perfection.
Eventually, some AI systems will have both great technical ability
and the social ability needed to understand human speech and wishes.
If given charge of energy, materials, and assemblers, such a system
might aptly be called a "genie machine." What you ask for, it will
produce. Arabian legend and universal common sense suggest that we
take the dangers of such engines of creation very seriously indeed.
Decisive breakthroughs in technical and social AI will be years in
arriving. As Marvin Minsky has said,*(98) "The modestly intelligent
machines of the near future promise only to bring us the wealth and
comfort of tireless, obedient, and inexpensive servants." Most systems
now called "AI" do not think or learn; they are only a crude
distillate of the skills of experts, preserved, packaged, and
distributed for consultation.
But genuine AI will arrive. To leave it out of our expectations
would be to live in a fantasy world. To expect AI is neither
optimistic nor pessimistic: as always, the researcher's optimism is
the technophobe's pessimism. If we do not prepare for their arrival,
social AI systems could pose a grave threat: consider the damage
done by the merely human intelligence of terrorists and demagogues.
Likewise, technical AI systems could destabilize the world military
balance, giving one side a sudden, massive lead. With proper
preparation, however, artificial intelligence could help us build a
future that works- for the Earth, for people, and for the
advancement of intelligence in the universe. Chapter 12 will suggest
an approach, as part of the more general issue of managing the
transformation that assemblers and AI will bring.
Why discuss the dangers today? Because it is not too soon to start
developing institutions able to deal with such questions. Technical AI
is emerging today, and its every advance will speed the technology
race. Artificial intelligence is but one of many powerful technologies
we must learn to manage, each adding to a complex mixture of threats
and opportunities.
6
The World Beyond Earth
-
That inverted Bowl we call The Sky
Whereunder crawling coop'd we live and die.
-The Rubaiyat of Omar Khayyam
-
THE EARTH is but a small part of the world, and the rest of the
world will be important to our future. In terms of energy,
materials, and room for growth, space is almost everything. In the
past, successes in space have regularly fulfilled engineering
projections. In the future, an open space frontier will widen the
human world. Advances in AI and nanotechnology will play a crucial
role.
People took ages to recognize space as a frontier. Our ancestors
once saw the night sky as a black dome with tiny sparks, a light
show of the gods. They couldn't imagine space travel, because they
didn't even know that outer space existed.
We now know that space exists, but few people yet understand its
value. This is hardly surprising. Our minds and cultures have
evolved on this planet, and we have just begun to digest the idea of a
frontier beyond the sky.
Only in this century did such visionary designers as Hermann
Oberth and Robert Goddard show that rockets could reach space. They
had confidence in this because they knew enough about fuel, engines,
tankage, and structures to calculate what multistage rockets could do.
Yet, in 1921 a New York Times editorialist chided Goddard for the
notion that rockets could fly through space without air to push
against, and as late as 1956 the Astronomer Royal of Britain snorted
that "Space travel is utter bilge." This only showed that
editorialists and astronomers were the wrong experts to ask about
space hardware. In 1957, Sputnik orbited Earth, followed in 1961 by
Yuri Gagarin. In 1969, the world saw footprints on the Moon.
We paid a price for ignorance, though. Because the pioneers of space
technology had lacked any way to establish their case in public,
they were forced to argue basic points again and again ("Yes,
rockets will work in vacuum.... Yes, they really will reach
orbit....). Busy defending the basics of spaceflight, they had
little time to discuss its consequences. Thus, when Sputnik startled
the world and embarrassed the United States, people were unprepared:
there had been no widespread debate to shape a strategy for space.
Some of the pioneers had seen what to do: build a space station
and a reusable spaceship, then reach out to the Moon or asteroids
for resources. But the noise of flustered politicians promptly drowned
out their suggestions, and U.S. politicians clamored for a big,
easy-to-understand goal. Thus was born Project Apollo, the race to
land a U.S. citizen on the nearest place to plant a flag. Project
Apollo bypassed building a space station and space shuttle, instead
building giant missiles able to reach the Moon in one great leap.
The project was glorious, it gave scientists some information, and
it brought great returns through advances in technology- but at the
core, it was a hollow stunt. Taxpayers saw this, congressmen saw this,
and the space program shriveled.
During Apollo, old dreams held sway in the public mind, and they
were simple, romantic dreams of settling other planets. Then robot
instruments dissolved the dream of a jungle-clad Venus in the
reality of a planet-wide oven of high-pressure poison. They erased the
lines Earthbound astronomers had drawn on Mars, and with them went
both canals and Martians. In their place was a Mars of craters and
canyons and dry blowing dust. Sunward of Venus lay the baked rock of
Mercury; starward of Mars lay rubble and ice. The planets ranged
from dead to murderous, and the dream of new Earths receded to distant
stars. Space seemed a dead end.
-
THE NEW SPACE PROGRAM
-
A new space program has risen from the ruin of the old. A new
generation of space advocates, engineers, and entrepreneurs now aims
to make space the frontier it should have been from the beginning- a
place for development and use, not for empty political gestures.
They have confidence in success because space development requires
no breakthroughs in science or technology. Indeed, the human race
could conquer space by applying the technologies of twenty years
ago- and by avoiding stunt flights, we could probably do it at a
profit. Space activities need not be expensive.
Consider the high cost of reaching orbit today- thousands of dollars
per kilogram. Where does it come from? To a spectator at a shuttle
launch, shaken by the roar and awed by the flames, the answer seems
obvious: the fuel must cost a mint. Even airlines pay roughly half
their direct operating costs for fuel. A rocket resembles an airliner-
it is made of aluminum and stuffed with engines, controls, and
electronics- but fuel makes up almost all its mass as it sits on the
launch pad. Thus, one might expect fuel to account for well over
half the operating cost of a rocket. But this expectation is false. In
the Moon shots, the cost of the fuel needed to reach orbit amounted to
less than a million dollars- a few dollars per kilogram delivered to
orbit, a fraction of a percent of the total cost. Even today, fuel
remains a negligible part of the cost of spaceflight.
Why is spaceflight so much costlier than air flight? In part,
because spacecraft aren't made in quantity; this forces
manufacturers to recover their design costs from sales of only a few
units, and to make those few units by hand at great cost. Further,
most spacecraft are thrown away after one use, and even shuttles are
flown just a few times a year- their cost cannot be spread over
several flights a day for years, as the cost of airliners can.
Finally, spaceport costs are now spread over only a few flights per
month, when large airports can spread their costs over many thousands.
All this conspires to make each flight into space dauntingly
expensive.
But studies by Boeing Aerospace Company- the people who brought
inexpensive jet transportation to much of the world- show that a fleet
of fully reusable shuttles, flown and maintained like airliners, would
drop the cost of reaching orbit by a factor of fifty or more. The
key is not new technology, but economies of scale and changes in
management style.
Space offers vast industrial opportunities. The advantages of
perching observation and communications satellites on orbit are well
known. Future communications satellites will be powerful enough to
communicate with hand-held stations on the ground, bringing the
ultimate in mobile telephone service. Companies are already moving
to take advantage of zero gravity to perform delicate separation
processes, to make improved pharmaceuticals; other companies plan to
grow better electronic crystals. In the years before assemblers take
over materials production, engineers will use the space environment to
extend the abilities of bulk technology. Space industry will provide a
growing market for launch services, dropping launch costs. Falling
launch costs, in turn, will stimulate the growth of space industry.
Rocket transportation to Earth orbit will eventually become
economical.
Space planners and entrepreneurs are already looking beyond Earth
orbit to the resources of the solar system. In deep space, however,
rockets swiftly become too expensive for hauling freight- they
gobble fuel that itself had to be hauled into space by rockets.
Fuel-burning rockets are as old as Chinese fireworks, far older than
"The Star-Spangled Banner." They evolved for natural reasons: compact,
powerful, and useful to the military, they can punch through air and
fight strong gravity. Space engineers know of alternatives,*(99)
however.
Vehicles need no great blasts of power to move through the
frictionless vacuum of space. Small forces can slowly and steadily
push a vehicle to enormous speeds. Because energy has mass, sunlight
bouncing off a thin mirror- a solar sail- provides such a force. The
pull of solar gravity provides another. Together, light pressure and
gravity can carry a spacecraft anywhere in the solar system and back
again. Only the heat near the Sun and the drag of planetary
atmospheres will limit travel, forcing sails to steer clear of them.
NASA has studied solar sails designed to be carried to space in
rockets, but these must be fairly heavy and sturdy to survive the
stress of launch and unfolding. Eventually, engineers will make
sails in space, using a low-mass tension structure to support
mirrors of thin metal film. The result will be the
"lightsail,"*(100) a higher-performance class of solar sail. After a
year's acceleration, a lightsail can reach a speed of one hundred
kilometers per second, leaving today's swiftest rockets in the dust.
If you imagine a network of graphite-fiber strands, a spinning
spiderweb kilometers wide with gaps the size of football fields
between the strands, you will be well on your way to imagining the
structure of a lightsail. If you picture the gaps bridged by
reflecting panels built of aluminum foil thinner than a soap bubble,
you will have a fair idea of how it looks: many reflective panels tied
close together to form a vast, rippled mosaic of mirror. Now picture a
load of cargo hanging from the web like a parachutist from a
parachute, while centrifugal force holds the web-slung mirror taut and
flat in the void, and you almost have it.
To build lightsails with bulk technology, we must learn to make them
in space; their vast reflectors will be too delicate to survive launch
and unfolding. We will need to construct scaffolding structures,
manufacture thin-film reflectors, and use remotely controlled robot
arms in space. But space planners already aim to master
construction, manufacturing, and robotics for other space
applications. If we build lightsails early in the course of space
development, the effort will exercise these skills without requiring
the launch of much material. Though vast, the scaffolding (together
with materials for many sails) will be light enough for one or two
shuttle flights to lift to orbit.
A sail production facility will produce sails cheaply. The sails,
once built, will be cheap to use: they will have few critical moving
parts, little mass, and zero fuel consumption. They will be utterly
different from rockets in form, function, and cost of operation. In
fact, calculations suggest that the costs will differ by a factor of
roughly a thousand, in favor of lightsails.
Today most people view the rest of the solar system as vast and
inaccessible. It is vast; like the Earth, it will take months to
circumnavigate by sail. Its apparent inaccessibility, however, has
less to do with distance than with the cost of transportation via
rocket.
Lightsails can smash the cost barrier, opening the door to the solar
system. Lightsails will make other planets easier to reach, but this
will not make planets much more useful: they will remain deadly
deserts. The gravity of planets will prevent lightsails from shuttling
to their surfaces, and will also handicap industry on a planet's
surface. Spinning space stations can simulate gravity if it is needed,
but planet-bound stations cannot escape it. Worse yet, planetary
atmospheres block solar energy, spread dust, corrode metals, warm
refrigerators, cool ovens, and blow things down. Even the airless Moon
rotates, blocking sunlight half the time, and has gravity enough to
ground lightsails beyond hope of escape. Lightsails are fast and
tireless, but not strong.
The great and enduring value of space lies in its resources of
matter, energy, and room. The planets occupy room and block energy.
The material resources they offer are inconveniently placed. The
asteroids, in contrast, are flying mountains of resources*(101) that
trace orbits crisscrossing the entire solar system. Some cross the
orbit of Earth; some have even struck Earth, blasting craters.
Mining the asteroids seems practical. We may need roaring rockets to
carry things up into space, but meteorites prove that ordinary rocks
can fall down from space- and like the space shuttle, objects
failing from space need not burn up on the way down. Delivering
packages of material from an asteroid to a landing target in a salt
flat will cost little.
Even small asteroids are big in human terms: they hold billions of
tons of resources. Some asteroids contain water and a substance
resembling oil shale. Some contain fairly ordinary rock. Some
contain a metal that holds elements scarce in Earth's crust,
elements that sank beyond reach ages ago in the formation of Earth's
metal core: this meteoritic steel is a strong, tough alloy of iron,
nickel, and cobalt, bearing valuable amounts of platinum-group
metals and gold. A kilometer-wide chunk of this material (and there
are many) contains precious metals worth several trillion dollars,
mixed with enough nickel and cobalt to supply Earth's industry for
many years.
The Sun floods space with easily collected energy. A
square-kilometer framework holding metal-film reflectors will gather
over a billion watts of sunlight, free of interference from cloud or
night. In the weatherless calm of space, the flimsiest collector
will be as permanent as a hydroelectric dam.*(102) Since the Sun
puts out as much energy in a microsecond as the human race now uses in
a year, energy need not be scarce for some time to come.
Finally, space itself offers room to live. People once saw life in
space in terms of planets. They imagined domed cities built on
planets, dead planets slowly converted into Earth-like planets, and
Earth-like planets reached after years in a flight to the stars. But
planets are package deals, generally offering the wrong gravity,
atmosphere, length of day, and location.
Free space offers a better building site for settlements.
Professor Gerard O'Neill*(103) of Princeton University brought this
idea to public attention, helping to revive interest in space after
the post-Apollo crash. He showed that ordinary construction materials-
steel and glass- could be used to build habitable cylinders in
space, kilometers in length and circumference. In his design, dirt
underfoot shields inhabitants from the natural radiation of space,
just as Earth's inhabitants are shielded by the air overhead. Rotation
produces an acceleration equaling Earth's gravity, and broad mirrors
and window panels flood the interior with sunlight. Add soil, streams,
vegetation, and imagination, and the lands inside could rival the best
valleys on Earth as places to live. With just the resources of the
asteroids, we will be able to build the practical equivalent of a
thousand new Earths.
By adapting present technology, we could open the space frontier.
The prospect is heartening. It shows us an obvious way to bypass
terrestrial limits to growth, lessening one of the fears that has
clouded our view of the future. The promise of the space frontier
can thus mobilize human hope- a resource we will need in abundance, if
we are to deal with other problems.
-
SPACE AND ADVANCED TECHNOLOGY
-
By adapting present technology, we could indeed open the space
frontier- but we won't. Along the path foreseen by the current space
movement, human civilization would take decades to become firmly
established in space. Before then, breakthroughs in technology will
open new paths.
Nowadays, teams of engineers typically take five to ten years to
develop a new space system, spending tens to thousands of millions
of dollars along the way. These engineering delays and costs make
progress painfully slow. In coming years, though, computer-aided
design systems will evolve toward automated engineering systems. As
they do, engineering delays and costs will shrink and then plummet;
computer-controlled manufacturing systems will drop overall costs
still further. A day will come when automated design and manufacturing
will have made space systems development more than tenfold faster
and cheaper. Our progress in space will soar.
At that time, will space settlers look back on our present space
program as the key to space development? Perhaps not. They will have
seen more technical progress made in a few years than space
engineers previously managed in a few decades. They may well
conclude that AI and robotics did more for space development than
did a whole army of NASA engineers.
The assembler breakthrough and automated engineering will combine to
bring advances that will make our present space efforts seem quaint.
In Chapter 4, I described how replicating assemblers will be able to
build a light, strong rocket engine using little human labor. Using
similar methods, we will build entire spacecraft of low cost and
extraordinary performance. Weight for weight, their diamond-based
structural materials will have roughly fifty times the strength (and
fourteen times the stiffness) of the aluminum used in the present
shuttle; vehicles built with these materials can be made over 90
percent lighter than similar vehicles today. Once in space, vehicles
will spread solar collectors to gather abundant energy. Using this
energy to power assemblers*(104) and disassemblers, they will
rebuild themselves in flight to suit changing conditions or the whim
of their passengers. Today, space travel is a challenge. Tomorrow,
it will be easy and convenient.
Since nanotechnology lends itself to making small things, consider
the smallest person-carrying spacecraft: the spacesuit. Forced to
use weak, heavy, passive materials, engineers now make bulky, clumsy
spacesuits. A look at an advanced spacesuit will illustrate some of
the capabilities of nanotechnology.
Imagine that you are aboard a space station, spun to simulate
Earth's normal gravity. After instruction, you have been given a
suit to try out: there it hangs on the wall, a gray, rubbery-looking
thing with a transparent helmet. You take it down, heft its
substantial weight, strip, and step in through the open seam on the
front.
The suit feels softer than the softest rubber, but has a slick inner
surface. It slips on easily and the seam seals at a touch. It provides
a skintight covering like a thin leather glove around your fingers,
thickening as it runs up your arm to become as thick as your hand in
the region around your torso. Behind your shoulders, scarcely
noticeable, is a small backpack. Around your head, almost invisible,
is the helmet. Below your neck the suit's inner surface hugs your skin
with a light, uniform touch that soon becomes almost imperceptible.
You stand up and walk around, experimenting. You bounce on your toes
and feel no extra weight from the suit. You bend and stretch and
feel no restraint, no wrinkling, no pressure points. When you rub your
fingers together they feel sensitive, as if bare- but somehow slightly
thicker. As you breathe, the air tastes clean and fresh. In fact,
you feel that you could forget that you are wearing a suit at all.
What is more, you feel just as comfortable when you step out into
the vacuum of space.
The suit manages to do all this and more by means of complex
activity within a structure having a texture almost as intricate as
that of living tissue. A glove finger a millimeter thick has room
for a thousand micron-thick layers of active nanomachinery and
nanoelectronics. A fingertip-sized patch has room for a billion
mechanical nanocomputers, with 99.9 percent of the volume left over
for other components.
In particular, this leaves room for an active structure. The
middle layer of the suit material*(105) holds a three-dimensional
weave of diamond-based fibers acting much like artificial muscle,
but able to push as well as pull (as discussed in the Notes). These
fibers take up much of the volume and make the suit material as strong
as steel. Powered by microscopic electric motors and controlled by
nanocomputers, they give the suit material its supple strength, making
it stretch, contract, and bend as needed. When the suit felt soft
earlier, this was because it had been programmed to act soft. The suit
has no difficulty holding its shape in a vacuum; it has strength
enough to avoid blowing up like a balloon. Likewise, it has no
difficulty supporting its own weight and moving to match your motions,
quickly, smoothly, and without resistance. This is one reason why it
almost seems not to be there at all.
Your fingers feel almost bare because you feel the texture of what
you touch. This happens because pressure sensors cover the suit's
surface and active structure covers its lining: the glove feels the
shape of whatever you touch- and the detailed pattern of pressure it
exerts- and transmits the same texture pattern to your skin. It also
reverses the process, transmitting to the outside the detailed pattern
of forces exerted by your skin on the inside of the glove. Thus the
glove pretends that it isn't there, and your skin feels almost bare.
The suit has the strength of steel and the flexibility of your own
body. If you reset the suit's controls, the suit continues to match
your motions, but with a difference. Instead of simply transmitting
the forces you exert, it amplifies them by a factor of ten.
Likewise, when something brushes against you, the suit now transmits
only a tenth of the force*(106) to the inside. You are now ready for a
wrestling match with a gorilla.
The fresh air you breathe may not seem surprising; the backpack
includes a supply of air and other consumables. Yet after a few days
outside in the sunlight, your air will not run out: like a plant,
the suit absorbs sunlight and the carbon dioxide you exhale, producing
fresh oxygen. Also like a plant (or a whole ecosystem), it breaks down
other wastes into simple molecules and reassembles them into the
molecular patterns of fresh, wholesome food. In fact, the suit will
keep you comfortable,*(107) breathing, and well fed almost anywhere in
the inner solar system.
What is more, the suit is durable. It can tolerate the failure of
numerous nanomachines because it has so many others to take over the
load. The space between the active fibers leaves room enough for
assemblers and disassemblers to move about and repair damaged devices.
The suit repairs itself as fast as it wears out.
Within the bounds of the possible, the suit could have many other
features. A speck of material smaller than a pinhead could hold the
text of every book ever published, for display on a fold-out screen.
Another speck could be a "seed" containing the blueprints for a
range of devices greater than the total the human race has yet
built,*(108) along with replicating assemblers able to make any or all
of them.
What is more, fast technical AI systems like those described in
the last chapter could design the suit in a morning*(109) and have
it built by afternoon.
All that we accomplish in space with modern bulk technology will
be swiftly and dramatically surpassed shortly after molecular
technology and automated engineering arrive. In particular, we will
build replicating assemblers that work in space.*(110) These
replicators will use solar energy as plants do, and with it they
will convert asteroidal rubble into copies of themselves and
products for human use. With them, we will grasp the resources of
the solar system.
-
By now, most readers will have noted that this, like certain earlier
discussions, sounds like science fiction. Some may be pleased, some
dismayed that future possibilities do in fact have this quality. Some,
though, may feel that "sounding like science fiction" is somehow
grounds for dismissal. This feeling is common and deserves scrutiny.
Technology and science fiction have long shared a curious
relationship. In imagining future technologies, SF writers have been
guided partly by science, partly by human longings, and partly by
the market demand for bizarre stories. Some of their imaginings
later become real, because ideas that seem plausible and interesting
in fiction sometimes prove possible and attractive in actuality.
What is more, when scientists and engineers foresee a dramatic
possibility, such as rocket-powered spaceflight, SF writers commonly
grab the idea and popularize it.
Later, when engineering advances bring these possibilities closer to
realization, other writers examine the facts and describe the
prospects. These descriptions, unless they are quite abstract, then
sound like science fiction. Future possibilities will often resemble
today's fiction, just as robots, spaceships, and computers resemble
yesterday's fiction. How could it be otherwise? Dramatic new
technologies sound like science fiction because science fiction
authors, despite their frequent fantasies, aren't blind and have a
professional interest in the area.
Science fiction authors often fictionalize (that is, counterfeit)
the scientific content of their stories to "explain" dramatic
technologies. Some fuzzy thinkers then take all descriptions of
dramatic technical advances, lump them together with this bogus
science, and ignore the lot. This is unfortunate. When engineers
project future abilities, they test their ideas, evolving them to
fit our best understanding of the laws of nature. The resulting
concepts must be distinguished from ideas evolved to fit the demands
of paperback fiction. Our lives will depend on it.
-
Much will remain impossible, even with molecular technology. No
spacesuit, however marvelous, will be able to rocket back and forth
indefinitely at tremendous speeds, or survive great explosions, or
walk through walls, or even stay cool indefinitely in a hot isolated
room. We have far to go before reaching the limits of the possible,
yet limits exist. But this is a topic taken up later.
-
ABUNDANCE
-
Space resources join with assemblers and automated engineering
systems to round out the case for a future of great material
abundance. What this means can best be seen by examining costs.
Costs reflect the limits of our resources and abilities; high
costs indicate scarce resources and difficult goals. The prophets of
scarcity have in effect predicted steeply rising resource costs, and
with them a certain kind of future. Resource costs, however, always
depend on technology. Unfortunately, engineers attempting to predict
the cost of future technologies have generally encountered a tangle of
detail and uncertainty that proves impossible to untie. This problem
has obscured our understanding of the future.
The prospect of replicating assemblers, automated engineering, and
space resources cuts this Gordian knot of cost prediction. Today the
cost of products includes the costs of labor, capital, raw
materials, energy, land, waste disposal, organization, distribution,
taxation, and design. To see how total costs will change, consider
these elements one by one.
Labor. Replicating assemblers will require no labor to build, once
the first exists. What use are human hands in running an assembler?
Further, with robotic devices of various sizes to assemble parts
into larger systems, the entire manufacturing process from
assembling molecules to assembling skyscrapers could be free of
labor costs.
Capital. Assembler-based systems, if properly programmed, will
themselves be productive capital. Together with larger robotic
machines, they will be able to build virtually anything, including
copies of themselves. Since this self-replicating capital will be able
to double many times per day, only demand and available resources will
limit its quantity. Capital as such need cost virtually nothing.
Raw materials. Since molecular machines will arrange atoms to best
advantage, a little material can go a long way. Common elements like
hydrogen, carbon, nitrogen, oxygen, aluminum, and silicon seem best
for constructing the bulk of most structures, vehicles, computers,
clothes and so forth: they are light and form strong bonds. Because
dirt and air contain these elements in abundance, raw materials can be
dirt cheap.
Energy. Assemblers will be able to run off chemical or electrical
energy. Assembler-built systems will convert solar to chemical energy,
like plants, or solar to electrical energy, like solar cells. Existing
solar cells are already more efficient than plants. With replicating
assemblers to build solar collectors, fuel and electric power will
cost little.
Land. Assembler-based production systems will occupy little room.
Most could sit in a closet (or a thimble, or a pinhole); larger
systems could be placed underground or in space if someone wants
something that requires an unsightly amount of room. Assembler-based
production systems will make both digging machines and spacecraft
cheap.
Waste disposal. Assembler systems will be able to keep control of
the atoms they use, making production as clean as a growing apple
tree, or cleaner. If the orchard remains too dirty or ugly, we will be
able to move it off Earth entirely.*(111)
Organization. Today, factory production requires organization to
coordinate hordes of workers and managers. Assembler-based
production machines will contain no people, and will simply sit around
and produce things made to order. Their initial programming will
provide all the organization and information needed to make a wide
range of products.
Distribution. With automatic vehicles running in tunnels made by
cheap digging machines, distribution need neither consume labor nor
blight the landscape. With assemblers in the home and community, there
will be less need for distribution in the first place.
Taxation. Most taxes take a fixed percentage of a price, and thus
add a fixed percentage to the cost. If the cost is negligible, the tax
will be negligible. Further, governments with their own replicators
and raw materials will have less reason to tax people.
Design. The above points add up to a case for low costs of
production. Technical AI systems, by avoiding the labor cost of
engineering, will virtually eliminate the costs of design. These AI
systems will themselves be inexpensive to produce and operate, being
constructed by assemblers and having no inclination to do anything but
design things.
-
In short, at the end of a long line of profitable developments in
computer and molecular technologies, the cost of designing and
producing things will drop dramatically. I above referred to "dirt
cheap" raw materials, and indeed, assemblers will be able to make
almost anything from dirt and sunlight. Space resources, however, will
change "dirt cheap" to "cheap-dirt cheap": topsoil has value in
Earth's ecosystem, but rubble from asteroids will come from a dead and
dreary desert. By the same token, assemblers in space will run off
cheap sunlight.
Space resources are vast. One asteroid could bury Earth's continents
a kilometer deep in raw materials. Space swallows the 99.999999955
percent of the Sun's light that misses Earth, and most is lost to
the interstellar void.
Space holds matter, energy, and room enough for projects of vast
size, including vast space settlements. Replicator-based systems
will be able to construct worlds of continental scale, resembling
Dr. O'Neill's cylinders but made of strong, carbon-based materials.
With these materials and water from the ice moons of the outer solar
system, we will be able to create not only lands in space, but whole
seas, wider and deeper than the Mediterranean. Constructed with energy
and materials from space, these broad new lands and seas will cost
Earth and its people almost nothing in terms of resources. The chief
requirement will be programming the first replicator, but AI systems
will help with that. The greatest problem will be deciding what we
want.
As Konstantin Tsiolkovsky wrote*(112) near the turn of the
century, "Man will not always stay on Earth; the pursuit of light
and space will lead him to penetrate the bounds of the atmosphere,
timidly at first, but in the end to conquer the whole of solar space."
To dead space we will bring life.
And replicators will give us the resources to reach for the stars. A
lightsail driven starward only by sunlight would soon find itself
coasting in the dark- faster than any modern rocket, yet so slowly
that it would take millennia to cross the interstellar gulf. We can
build a tremendous bank of lasers orbiting the Sun, however, and
with it drive a beam far beyond our solar system,*(113) pushing a sail
toward the speed of light. The crossing then will take only years.
Stopping presents a problem. Freeman Dyson of Princeton
suggests*(114) braking with magnetic fields in the thin ionized gas
between the stars. Robert Forward of Hughes Research Laboratories
suggests*(115) bouncing laser light off the sail, directing light back
along the sail's path to decelerate a smaller sail trailing behind.
One way or another (and there are many others), the stars themselves
lie within our reach.
For a long time to come, however, the solar system can provide
room enough. The space near Earth holds*(116) room for lands with a
million times Earth's area. Nothing need stop emigration, or return
visits to the old country. We will have no trouble powering the
transportation system- the sunlight falling on Earth supplies enough
energy in ten minutes*(117) to put today's entire population in orbit.
Space travel and space settlements will both become cheap. If we
make wise use of molecular technology, our descendants will wonder
what kept us bottled up on Earth for so long, and in such poverty.
-
THE POSITIVE-SUM SOCIETY
-
It might seem that the cost of everything- even land, if one doesn't
crave thousands of kilometers of rock underfoot- will drop to nothing.
In a sense, this is almost right; in another sense, it is quite false.
People will always value matter, energy, information, and genuine
human service, therefore everything will still have its cost. And in
the long run, we will face real limits to growth, so the cost of
resources cannot be dismissed.
Nonetheless, if we survive, replicators and space resources will
bring a long era in which genuine resource limits do not yet pinch us-
an era when by our present standards even vast wealth will seem
virtually free. This may seem too good to be true, but nature (as
usual) has not set her limits based on human feelings. Our ancestors
once thought that talking to someone across the sea (many months'
voyage by sailing ship) would be too good to be true, but undersea
cables and oversea satellites worked anyway.
But there is another, less pleasant answer for those who think
assemblers are too good to be true: assemblers also threaten to
bring hazards and weapons more dangerous than any yet seen. If
nanotechnology could be avoided but not controlled, then sane people
would shun it. The technology race, however, will bring forth
assemblers from biotechnology as surely as it brought forth spacecraft
from missiles. The military advantages alone will be enough to make
advances almost inevitable. Assemblers are unavoidable, but perhaps
controllable.
Our challenge is to avoid the dangers, but this will take
cooperation, and we are more likely to cooperate if we understand
how much we have to gain from it. The prospect of space and
replicating assemblers may help us clear away some ancient and
dangerous memes.
Human life was once like a zero-sum game. Humankind lived near its
ecological limit and tribe fought tribe for living space. Where
pastures, farmland, and hunting grounds were concerned, more for one
group meant less for another. Because one's gain roughly equaled the
other's loss, net benefits summed to zero. Still, people who
cooperated on other matters prospered, and so our ancestors learned
not just to grab, but to cooperate and build.
Where taxes, transfer payments, and court battles are concerned,
more for one still means less for another. We add to total wealth
slowly, but redistribute it swiftly. On any given day our resources
seem fixed, and this gives rise to the illusion that life is a
zero-sum game. This illusion suggests that broad cooperation is
pointless, because our gain must result from some opponent's loss.
The history of human advance proves that the world game can be
positive-sum. Accelerating economic growth during recent centuries
shows that the rich can get richer while the poor get richer.
Despite population growth (and the idea of dividing a fixed pie) the
average wealth per capita worldwide, including that of the Third
World, has grown steadily larger. Economic fluctuations, local
reversals, and the natural tendency of the media to focus on bad news-
these combine to obscure the facts about economic growth, but public
records show it clearly enough. Space resources and replicating
assemblers will accelerate this historic trend beyond the dreams of
economists, launching the human race into a new world.
7
Engines of Healing
-
One of the things which distinguishes ours from all earlier
generations is this, that we have seen our atoms.
-KARL K. DARROW, The Renaissance of Physics
-
WE WILL USE molecular technology to bring health because the human
body is made of molecules. The ill, the old, and the injured all
suffer from misarranged patterns of atoms, whether misarranged by
invading viruses, passing time, or swerving cars. Devices able to
rearrange atoms will be able to set them right. Nanotechnology will
bring a fundamental breakthrough in medicine.
Physicians now rely chiefly on surgery and drugs to treat illness.
Surgeons have advanced from stitching wounds and amputating limbs to
repairing hearts and reattaching limbs. Using microscopes and fine
tools, they join delicate blood vessels and nerves. Yet even the
best microsurgeon cannot cut and stitch finer tissue structures.
Modern scalpels and sutures are simply too coarse for repairing
capillaries, cells, and molecules. Consider "delicate" surgery from
a cell's perspective: a huge blade sweeps down, chopping blindly
past and through the molecular machinery of a crowd of cells,
slaughtering thousands. Later, a great obelisk plunges through the
divided crowd, dragging a cable as wide as a freight train behind it
to rope the crowd together again. From a cell's perspective, even
the most delicate surgery, performed with exquisite knives and great
skill, is still a butcher job. Only the ability of cells to abandon
their dead, regroup, and multiply makes healing possible.
Yet as many paralyzed accident victims know too well, not all
tissues heal.
Drug therapy, unlike surgery, deals with the finest structures in
cells. Drug molecules are simple molecular devices. Many affect
specific molecules in cells. Morphine molecules, for example, bind
to certain receptor molecules in brain cells, affecting the neural
impulses that signal pain. Insulin, beta blockers, and other drugs fit
other receptors. But drug molecules work without direction. Once
dumped into the body, they tumble and bump around in solution
haphazardly until they bump a target molecule, fit, and stick,
affecting its function.
Surgeons can see problems and plan actions, but they wield crude
tools; drug molecules affect tissues at the molecular level, but
they are too simple to sense, plan, and act. But molecular machines
directed by nanocomputers will offer physicians another choice. They
will combine sensors, programs, and molecular tools to form systems
able to examine and repair the ultimate components of individual
cells. They will bring surgical control to the molecular domain.
These advanced molecular devices will be years in arriving, but
researchers motivated by medical needs are already studying
molecular machines and molecular engineering. The best drugs affect
specific molecular machines in specific ways. Penicillin, for example,
kills certain bacteria by jamming the nanomachinery they use to
build their cell walls, yet it has little effect on human cells.
Biochemists study molecular machines both to learn how to build them
and to learn how to wreck them. Around the world (and especially the
Third World) a disgusting variety of viruses, bacteria, protozoa,
fungi, and worms parasitize human flesh. Like penicillin, safe,
effective drugs for these diseases would jam the parasite's
molecular machinery while leaving human molecular machinery
unharmed. Dr. Seymour Cohen, professor of pharmacological science at
SUNY (Stony Brook, New York), argues*(118) that biochemists should
systematically study the molecular machinery of these parasites.
Once biochemists have determined the shape and function of a vital
protein machine, they then could often design a molecule shaped to jam
it and ruin it. Such drugs could free humanity from such ancient
horrors as schistosomiasis and leprosy, and from new ones such as
AIDS.
Drug companies are already redesigning molecules based on
knowledge of how they work. Researchers at Upjohn Company*(119) have
designed and made modified molecules of vasopressin, a hormone that
consists of a short chain of amino acids. Vasopressin increases the
work done by the heart and decreases the rate at which the kidneys
produce urine; this increases blood pressure. The researchers designed
modified vasopressin molecules that affected receptor molecules in the
kidney more than those in the heart, giving them more specific and
controllable medical effects. More recently, they designed a
modified vasopressin molecule that binds to the kidney's receptor
molecules without direct effect, thus blocking and inhibiting the
action of natural vasopressin.
Medical needs will push this work forward, encouraging researchers
to take further steps toward protein design and molecular engineering.
Medical, military, and economic pressures all push us in the same
direction. Even before the assembler breakthrough, molecular
technology will bring impressive advances in medicine; trends in
biotechnology guarantee it. Still, these advances will generally be
piecemeal and hard to predict, each exploiting some detail of
biochemistry. Later, when we apply assemblers and technical AI systems
to medicine, we will gain broader abilities that are easier to
foresee.
To understand these abilities, consider cells and their
self-repair mechanisms. In the cells of your body, natural radiation
and noxious chemicals split molecules, producing reactive molecular
fragments. These can misbond to other molecules in a process called
cross-linking. As bullets and blobs of glue would damage a machine, so
radiation and reactive fragments damage cells, both breaking molecular
machines and gumming them up.
If your cells could not repair themselves, damage would rapidly kill
them or make them run amok by damaging their control systems. But
evolution has favored organisms with machinery able to do something
about this problem. The self-replicating factory system sketched in
Chapter 4 repaired itself by replacing damaged parts; cells do the
same. So long as a cell's DNA remains intact, it can make error-free
tapes that direct ribosomes to assemble new protein machines.
Unfortunately for us, DNA itself becomes damaged, resulting in
mutations. Repair enzymes compensate somewhat by detecting and
repairing certain kinds of damage to DNA. These repairs help cells
survive, but existing repair mechanisms are too simple to correct
all problems, either in DNA or elsewhere. Errors mount, contributing
to the aging and death of cells- and of people.
-
LIFE, MIND, AND MACHINES
-
Does it make sense to describe cells as "machinery," whether
self-repairing or not? Since we are made of cells, this might seem
to reduce human beings to "mere machines," conflicting with a holistic
understanding of life.
But a dictionary definition of holism*(120) is "the theory that
reality is made up of organic or unified wholes that are greater
than the simple sum of their parts." This certainly applies to people:
one simpler sum of our parts would resemble hamburger, lacking both
mind and life.
The human body includes some ten thousand billion billion protein
parts, and no machine so complex deserves the label "mere." Any
brief description of so complex a system cannot avoid being grossly
incomplete, yet at the cellular level a description in terms of
machinery makes sense. Molecules have simple moving parts, and many
act like familiar types of machinery. Cells considered as a whole
may seem less mechanical, yet biologists find it useful to describe
them in terms of molecular machinery.
Biochemists have unraveled what were once the central mysteries of
life, and have begun to fill in the details. They have traced how
molecular machines break food molecules into their building blocks and
then reassemble these parts to build and renew tissue. Many details of
the structure of human cells remain unknown (single cells have
billions of large molecules of thousands of different kinds), but
biochemists have mapped every part of some viruses. Biochemical
laboratories often sport a large wall chart showing how the chief
molecular building blocks flow through bacteria. Biochemists
understand much of the process of life in detail, and what they
don't understand seems to operate on the same principles. The
mystery of heredity has become the industry of genetic engineering.
Even embryonic development and memory are being explained in terms
of changes in biochemistry and cell structure.
In recent decades, the very quality of our remaining ignorance has
changed. Once, biologists looked at the process of life and asked,
"How can this be?" But today they understand the general principles of
life, and when they study a specific living process they commonly ask,
"Of the many ways this could be, which has nature chosen?" In many
instances their studies have narrowed the competing explanations to
a field of one. Certain biological processes- the coordination of
cells to form growing embryos, learning brains, and reacting immune
systems- still present a real challenge to the imagination. Yet this
is not because of some deep mystery about how their parts work, but
because of the immense complexity of how their many parts interact
to form a whole.
Cells obey the same natural laws that describe the rest of the
world. Protein machines in the right molecular environment will work
whether they remain in a functioning cell or whether the rest of the
cell was ground up and washed away days before. Molecular machines
know nothing of "life" and "death."
Biologists- when they bother- sometimes define life as the ability
to grow, replicate, and respond to stimuli. But by this standard, a
mindless system of replicating factories might qualify as life,
while a conscious artificial intelligence modeled on the human brain
might not. Are viruses alive, or are they "merely" fancy molecular
machines? No experiment can tell, because nature draws no line between
living and nonliving. Biologists who work with viruses instead ask
about viability: "Will this virus function, if given a chance?" The
labels of "life" and "death" in medicine depend on medical
capabilities: physicians ask, "Will this patient function, if we do
our best?" Physicians once declared patients dead when the heart
stopped; they now declare patients dead when they despair of restoring
brain activity. Advances in cardiac medicine changed the definition
once; advances in brain medicine will change it again.
Just as some people feel uncomfortable with the idea of machines
thinking, so some feel uncomfortable with the idea that machines
underlie our own thinking. The word "machine" again seems to conjure
up the wrong image, a picture of gross, clanking metal, rather than
signals flickering through a shifting weave of neural fibers,
through a living tapestry more intricate than the mind it embodies can
fully comprehend. The brain's really machinelike machines are of
molecular size, smaller than the finest fibers.
A whole need not resemble its parts. A solid lump scarcely resembles
a dancing fountain, yet a collection of solid, lumpy molecules forms
fluid water. In a similar way, billions of molecular machines make
up neural fibers and synapses, thousands of fibers and synapses make
up a neural cell, billions of neural cells make up the brain, and
the brain itself embodies the fluidity of thought.
To say that the mind is "just molecular machines" is like saying
that the Mona Lisa is "just dabs of paint." Such statements confuse
the parts with the whole, and confuse matter with the pattern it
embodies. We are no less human for being made of molecules.
-
FROM DRUGS TO CELL REPAIR MACHINES
-
Being made of molecules, and having a human concern for our
health, we will apply molecular machines to biomedical technology.
Biologists already use antibodies to tag proteins, enzymes to cut
and splice DNA, and viral syringes (like the T4 phage) to inject
edited DNA into bacteria. In the future, they will use assembler-built
nanomachines to probe and modify cells.
With tools like disassemblers, biologists will be able to study cell
structures in ultimate, molecular detail. They then will catalog the
hundreds of thousands of kinds of molecules in the body and map the
structure of the hundreds of kinds of cells. Much as engineers might
compile a parts list and make engineering drawings for an
automobile, so biologists will describe the parts and structures of
healthy tissue. By that time, they will be aided by sophisticated
technical AI systems.*(121)
Physicians aim to make tissues healthy, but with drugs and surgery
they can only encourage tissues to repair themselves. Molecular
machines will allow more direct repairs, bringing a new era in
medicine.
To repair a car, a mechanic first reaches the faulty assembly,
then identifies and removes the bad parts, and finally rebuilds or
replaces them. Cell repair will involve the same basic tasks- tasks
that living systems already prove possible.
-
Access. White blood cells leave the bloodstream and move through
tissue, and viruses enter cells. Biologists even poke needles into
cells without killing them. These examples show that molecular
machines can reach and enter cells.
Recognition. Antibodies and the tail fibers of the T4 phage- and
indeed, all specific biochemical interactions- show that molecular
systems can recognize other molecules by touch.
Disassembly. Digestive enzymes (and other, fiercer chemicals) show
that molecular systems can disassemble damaged molecules.
Rebuilding. Replicating cells show that molecular systems can
build or rebuild every molecule found in a cell.
Reassembly. Nature also shows that separated molecules can be put
back together*(122) again. The machinery of the T4 phage, for example,
self-assembles*(123) from solution, apparently aided by a single
enzyme. Replicating cells show that molecular systems can assemble
every system found in a cell.
-
Thus, nature demonstrates all the basic operations that are needed
to perform molecular-level repairs on cells. What is more, as I
described in Chapter 1, systems based on nanomachines will generally
be more compact and capable than those found in nature. Natural
systems show us only lower bounds to the possible, in cell repair as
in everything else.
-
CELL REPAIR MACHINES
-
In short, with molecular technology and technical AI we will compile
complete, molecular-level descriptions of healthy tissue, and we
will build machines able to enter cells and to sense and modify
their structures.
Cell repair machines will be comparable in size to bacteria and
viruses, but their more-compact parts will allow them to be more
complex. They will travel through tissue as white blood cells do,
and enter cells as viruses do- or they could open and close cell
membranes with a surgeon's care. Inside a cell, a repair machine
will first size up the situation by examining the cell's contents
and activity, and then take action. Early cell repair machines will be
highly specialized, able to recognize and correct only a single type
of molecular disorder, such as an enzyme deficiency or a form of DNA
damage. Later machines (but not much later, with advanced technical AI
systems doing the design work) will be programmed with more general
abilities.
Complex repair machines will need nanocomputers to guide them. A
micron-wide mechanical computer like that described in Chapter 1
will fit in 1/1000 of the volume of a typical cell, yet will hold more
information than does the cell's DNA. In a repair system, such
computers will direct smaller, simpler computers, which will in turn
direct machines to examine, take apart, and rebuild damaged
molecular structures.
By working along molecule by molecule and structure by structure,
repair machines will be able to repair whole cells. By working along
cell by cell and tissue by tissue, they (aided by larger devices,
where need be) will be able to repair whole organs. By working through
a person organ by organ, they will restore health. Because molecular
machines will be able to build molecules and cells from scratch,
they will be able to repair even cells damaged to the point of
complete inactivity. Thus, cell repair machines will bring a
fundamental breakthrough: they will free medicine from reliance on
self-repair as the only path to healing.
To visualize an advanced cell repair machine, imagine it- and a
cell- enlarged until atoms are the size of small marbles. On this
scale, the repair machine's smallest tools have tips about the size of
your fingertips; a medium-sized protein, like hemoglobin, is the
size of a typewriter, and a ribosome is the size of a washing machine.
A single repair device contains a simple computer the size of a
small truck, along with many sensors of protein size, several
manipulators of ribosome size, and provisions for memory and motive
power. A total volume ten meters across, the size of a three-story
house, holds all these parts and more. With parts the size of
marbles packing this volume, the repair machine can do complex things.
But this repair device does not work alone. It, like its many
siblings, is connected to a larger computer by means of mechanical
data links the diameter of your arm. On this scale, a cubic-micron
computer with a large memory fills a volume thirty stories high and as
wide as a football field. The repair devices pass it information,
and it passes back general instructions. Objects so large and
complex are still small enough: on this scale, the cell itself is a
kilometer across, holding one thousand times the volume of a
cubic-micron computer, or a million times the volume of a single
repair device. Cells are spacious.
Will such machines be able to do everything necessary to repair
cells? Existing molecular machines demonstrate the ability to travel
through tissue, enter cells, recognize molecular structures, and so
forth, but other requirements are also important. Will repair machines
work fast enough? If they do, will they waste so much power that the
patient will roast?
The most extensive repairs cannot require vastly more work than
building a cell from scratch. Yet molecular machinery working within a
cellular volume routinely does just that, building a new cell in
tens of minutes (in bacteria) to a few hours (in mammals). This
indicates that repair machinery occupying a few percent of a cell's
volume will be able to complete even extensive repairs in a reasonable
time- days or weeks at most. Cells can spare this much room. Even
brain cells can still function when an inert waste called lipofuscin
(apparently a product of molecular damage) fills over ten
percent*(124) of their volume.
Powering repair devices will be easy: cells naturally contain
chemicals that power nanomachinery. Nature also shows that repair
machines can be cooled: the cells in your body rework themselves
steadily, and young animals grow swiftly without cooking themselves.
Handling heat from a similar level of activity by repair machines will
be no sweat- or at least not too much sweat, if a week of sweating
is the price of health.
All these comparisons of repair machines to existing biological
mechanisms raise the question of whether repair machines will be
able to improve on nature. DNA repair provides a clear-cut
illustration.
Just as an illiterate "book-repair machine" could recognize and
repair a torn page, so a cell's repair enzymes can recognize and
repair breaks and cross-links in DNA. Correcting misspellings (or
mutations), though, would require an ability to read. Nature lacks
such repair machines, but they will be easy to build. Imagine three
identical DNA molecules, each with the same sequence of nucleotides.
Now imagine each strand mutated to change a few scattered nucleotides.
Each strand still seems normal, taken by itself. Nonetheless, a repair
machine could compare each strand to the others, one segment at a
time, and could note when a nucleotide failed to match its mates.
Changing the odd nucleotide to match the other two will then repair
the damage.
This method will fail if two strands mutate in the same spot.
Imagine that the DNA of three human cells has been heavily damaged-
after thousands of mutations, each cell has had one in every million
nucleotides changed. The chance of our three-strand correction
procedure failing at any given spot is then about one in a million
million. But compare five strands at once, and the odds become about
one in a million million million,*(125) and so on. A device that
compares many strands will make the chance of an uncorrectable error
effectively nil.
In practice, repair machines will compare DNA molecules from several
cells, make corrected copies,*(126) and use these as standards for
proofreading and repairing DNA throughout a tissue. By comparing
several strands, repair machines will dramatically improve on nature's
repair enzymes.
Other repairs will require different information about healthy cells
and about how a particular damaged cell differs from the norm.
Antibodies identify proteins by touch, and properly chosen
antibodies can generally distinguish any two proteins by their
differing shapes and surface properties. Repair machines will identify
molecules in a similar way.*(127) With a suitable computer and data
base, they will be able to identify proteins by reading their amino
acid sequences.
Consider a complex and capable repair system.*(128) A volume of
two cubic microns- about 2/1000 of the volume of a typical cell-
will be enough to hold a central data base system able to:
-
1. Swiftly identify any of the hundred thousand or so different
human proteins by examining a short amino acid sequence.
2. Identify all the other complex molecules normally found in cells.
3. Record the type and position of every large molecule in the cell.
-
Each of the smaller repair devices (of perhaps thousands in a
cell) will include a less capable computer. Each of these computers
will be able to perform over a thousand computational steps in the
time that a typical enzyme takes to change a single molecular bond, so
the speed of computation possible seems more than adequate. Because
each computer will be in communication*(129) with a larger computer
and the central data base, the available memory seems adequate. Cell
repair machines will have both the molecular tools they need and
"brains" enough to decide how to use them.
Such sophistication will be overkill (overcure?) for many health
problems. Devices that merely recognize and destroy a specific kind of
cell, for example, will be enough to cure a cancer. Placing a computer
network in every cell may seem like slicing butter with a chain saw,
but having a chain saw available does provide assurance that even hard
butter can be sliced. It seems better to show too much than too
little, if one aims to describe the limits of the possible in
medicine.
-
SOME CURES
-
The simplest medical applications of nanomachines will involve not
repair but selective destruction. Cancers provide one example;
infectious diseases provide another. The goal is simple: one need only
recognize and destroy the dangerous replicators, whether they are
bacteria, cancer cells, viruses, or worms. Similarly, abnormal growths
and deposits on arterial walls cause much heart disease; machines that
recognize, break down, and dispose of them will clear arteries for
more normal blood flow. Selective destruction will also cure
diseases such as herpes in which a virus splices its genes into the
DNA of a host cell. A repair device will enter the cell, read its DNA,
and remove the addition that spells "herpes."
Repairing damaged, cross-linked molecules will also be fairly
straightforward. Faced with a damaged, cross-linked protein, a cell
repair machine will first identify it by examining short amino acid
sequences, then look up its correct structure in a data base. The
machine will then compare the protein to this blueprint, one amino
acid at a time. Like a proofreader finding misspellings and strange
characters (char#cters), it will find any changed amino acids or
improper cross-links. By correcting these flaws, it will leave a
normal protein, ready to do the work of the cell.
Repair machines will also aid healing. After a heart attack, scar
tissue replaces dead muscle. Repair machines will stimulate the
heart to grow fresh muscle by resetting cellular control mechanisms.
By removing scar tissue and guiding fresh growth, they will direct the
healing of the heart.
This list could continue through problem after problem (Heavy
metal poisoning?- Find and remove the metal atoms) but the
conclusion is easy to summarize. Physical disorders stem from
misarranged atoms; repair machines will be able to return them to
working order, restoring the body to health. Rather than compiling
an endless list of curable diseases (from arthritis, bursitis, cancer,
and dengue to yellow fever and zinc chills and back again), it makes
sense to look for the limits to what cell repair machines can do.
Limits do exist.
Consider stroke, as one example of a problem that damages the brain.
Prevention will be straightforward: Is a blood vessel in the brain
weakening, bulging, and apt to burst? Then pull it back into shape and
guide the growth of reinforcing fibers. Does abnormal clotting
threaten to block circulation? Then dissolve the clots and normalize
the blood and blood-vessel linings to prevent a recurrence. Moderate
neural damage from stroke will also be repairable: if reduced
circulation has impaired function but left cell structures intact,
then restore circulation and repair the cells, using their
structures as a guide in restoring the tissue to its previous state.
This will not only restore each cell's function, but will preserve the
memories and skills embodied in the neural patterns in that part of
the brain.
Repair machines will be able to regenerate fresh brain tissue even
where damage has obliterated these patterns. But the patient would
lose old memories and skills to the extent that they resided in that
part of the brain. If unique neural patterns are truly obliterated,
then cell repair machines could no more restore them than art
conservators could restore a tapestry from stirred ash. Loss of
information through obliteration of structure imposes the most
important, fundamental limit to the repair of tissue.
Other tasks are beyond cell repair machines for different reasons-
maintaining mental health, for instance. Cell repair machines will
be able to correct some problems, of course. Deranged thinking
sometimes has biochemical causes, as if the brain were drugging or
poisoning itself, and other problems stem from tissue damage. But many
problems have little to do with the health of nerve cells and
everything to do with the health of the mind.
A mind and the tissue of its brain are like a novel and the paper of
its book. Spilled ink or flood damage may harm the book, making the
novel difficult to read. Book repair machines could nonetheless
restore physical "health" by removing the foreign ink or by drying and
repairing the damaged paper fibers. Such treatments would do nothing
for the book's content, however, which in a real sense is nonphysical.
If the book were a cheap romance with a moldy plot and empty
characters, repairs would be needed not on the ink and paper, but on
the novel. This would call not for physical repairs, but for more work
by the author, perhaps with advice.
Similarly, removing poisons from the brain and repairing its nerve
fibers will thin some mental fogs, but not revise the content of the
mind. This can be changed by the patient, with effort; we are all
authors of our minds. But because minds change themselves by
changing their brains, having a healthy brain will aid sound
thinking more than quality paper aids sound writing.
Readers familiar with computers may prefer to think in terms of
hardware and software. A machine could repair a computer's hardware
while neither understanding nor changing its software.
Such machines might stop the computer's activity but leave the
patterns in memory intact and ready to work again. In computers with
the right kind of memory (called "nonvolatile"), users do this by
simply switching off the power. In the brain the job seems more
complex, yet there could be medical advantages to inducing a similar
state.
-
ANESTHESIA PLUS
-
Physicians already stop and restart consciousness by interfering
with the chemical activity that underlies the mind. Throughout
active life, molecular machines in the brain process molecules. Some
disassemble sugars, combine them with oxygen, and capture the energy
this releases. Some pump salt ions across cell membranes; others build
small molecules and release them to signal other cells. Such processes
make up the brain's metabolism, the sum total of its chemical
activity. Together with its electrical effects, this metabolic
activity underlies the changing patterns of thought.
Surgeons cut people with knives. In the mid-1800s, they learned to
use chemicals that interfere with brain metabolism, blocking conscious
thought and preventing patients from objecting so vigorously to
being cut. These chemicals are anesthetics. Their molecules freely
enter and leave the brain, allowing anesthetists to interrupt and
restart human consciousness.
People have long dreamed of discovering a drug that interferes
with the metabolism of the entire body, a drug able to interrupt
metabolism completely for hours, days, or years. The result would be a
condition of biostasis (from bio, meaning life, and stasis, meaning
a stoppage or a stable state). A method of producing reversible
biostasis could help astronauts on long space voyages to save food and
avoid boredom, or it could serve as a kind of one-way time travel.
In medicine, biostasis would provide a deep anesthesia giving
physicians more time to work. When emergencies occur far from
medical help, a good biostasis procedure would provide a sort of
universal first-aid treatment: it would stabilize a patient's
condition and prevent molecular machines from running amok and
damaging tissues.
But no one has found a drug able to stop the entire metabolism the
way anesthetics stop consciousness- that is, in a way that can be
reversed by simply washing the drug out of the patient's tissues.
Nonetheless, reversible biostasis will be possible when repair
machines become available.
To see how one approach would work, imagine that the bloodstream
carries simple molecular devices to tissues, where they enter the
cells. There they block the molecular machinery of metabolism- in
the brain and elsewhere- and tie structures together with
stabilizing cross-links. Other molecular devices then move in,
displacing water and packing themselves solidly around the molecules
of the cell. These steps stop metabolism and preserve cell structures.
Because cell repair machines will be used to reverse this process,
it can cause moderate molecular damage and yet do no lasting harm.
With metabolism stopped and cell structures held firmly in place,
the patient will rest quietly, dreamless and unchanging, until
repair machines restore active life.
If a patient in this condition were turned over to a present-day
physician ignorant of the capabilities of cell repair machines, the
consequences would likely be grim. Seeing no signs of life, the
physician would likely conclude that the patient was dead, and then
would make this judgment a reality by "prescribing" an autopsy,
followed by burial or burning.
But our imaginary patient lives in an era when biostasis is known to
be only an interruption of life, not an end to it. When the
patient's contract says "wake me!" (or the repairs are complete, or
the flight to the stars is finished), the attending physician begins
resuscitation. Repair machines enter the patient's tissues, removing
the packing from around the patient's molecules and replacing it
with water. They then remove the cross-links, repair any damaged
molecules and structures, and restore normal concentrations of
salts, blood sugar, ATP, and so forth. Finally, they unblock the
metabolic machinery. The interrupted metabolic processes resume, the
patient yawns, stretches, sits up, thanks the doctor, checks the date,
and walks out the door.
-
FROM FUNCTION TO STRUCTURE
-
The reversibility of biostasis and irreversibility of severe
stroke damage help to show how cell repair machines will change
medicine. Today, physicians can only help tissues to heal
themselves. Accordingly, they must try to preserve the function of
tissue. If tissues cannot function, they cannot heal. Worse, unless
they are preserved, deterioration follows, ultimately obliterating
structure. It is as if a mechanic's tools were able to work only on
a running engine.
Cell repair machines change the central requirement from
preserving function to preserving structure. As I noted in the
discussion of stroke, repair machines will be able to restore brain
function with memory and skills intact only if the distinctive
structure of the neural fabric remains intact. Biostasis involves
preserving neural structure while deliberately blocking function.
All this is a direct consequence of the molecular nature of the
repairs. Physicians using scalpels and drugs can no more repair
cells than someone using only a pickax and a can of oil can repair a
fine watch. In contrast, having repair machines and ordinary nutrients
will be like having a watchmaker's tools and an unlimited supply of
spare parts. Cell repair machines will change medicine at its
foundations.
-
FROM TREATING DISEASE TO ESTABLISHING HEALTH
-
Medical researchers now study diseases, often seeking ways to
prevent or reverse them by blocking a key step in the disease process.
The resulting knowledge has helped physicians greatly: they now
prescribe insulin to compensate for diabetes, anti-hypertensives to
prevent stroke, penicillin to cure infections, and so on down an
impressive list. Molecular machines will aid the study of diseases,
yet they will make understanding disease far less important. Repair
machines will make it more important to understand health.
The body can be ill in more ways than it can be healthy. Healthy
muscle tissue, for example, varies in relatively few ways: it can be
stronger or weaker, faster or slower, have this antigen or that one,
and so forth. Damaged muscle tissue can vary in all these ways, yet
also suffer from any combination of strains, tears, viral
infections, parasitic worms, bruises, punctures, poisons, sarcomas,
wasting diseases, and congenital abnormalities. Similarly, though
neurons are woven in as many patterns as there are human brains,
individual synapses and dendrites come in a modest range of forms-
if they are healthy.
Once biologists have described normal molecules, cells, and tissues,
properly programmed repair machines will be able to cure even
unknown diseases. Once researchers describe the range of structures
that (for example) a healthy liver may have, repair machines exploring
a malfunctioning liver need only look for differences and correct
them. Machines ignorant of a new poison and its effects will still
recognize it as foreign and remove it. Instead of fighting a million
strange diseases, advanced repair machines will establish a state of
health.
Developing and programming cell repair machines will require great
effort, knowledge, and skill. Repair machines with broad
capabilities seem easier to build than to program. Their programs must
contain detailed knowledge of the hundreds of kinds of cells and the
hundreds of thousands of kinds of molecules in the human body. They
must be able to map damaged cellular structures*(130) and decide how
to correct them. How long will such machines and programs take to be
developed? Offhand, the state of biochemistry and its present rate
of advance might suggest that the basic knowledge alone will take
centuries to collect. But we must beware of the illusion that advances
will arrive in isolation.
Repair machines will sweep in with a wave of other technologies. The
assemblers that build them will first be used to build instruments for
analyzing cell structures. Even a pessimist might agree that human
biologists and engineers equipped with these tools could build and
program advanced cell repair machines in a hundred years of steady
work. A cocksure, far-seeing pessimist might say a thousand years. A
really committed nay-sayer might declare that the job would take
people a million years. Very well: fast technical AI systems- a
millionfold faster than scientists and engineers- will then develop
advanced cell repair machines in a single calendar year.*(131)
-
A DISEASE CALLED "AGING"
-
Aging is natural, but so were smallpox and our efforts to prevent
it. We have conquered smallpox, and it seems that we will conquer
aging.
Longevity has increased during the last century, but chiefly because
better sanitation and drugs have reduced bacterial illness. The
basic human lifespan has increased little.
Still, researchers have made progress toward understanding and
slowing the aging process. They have identified some of its causes,
such as uncontrolled cross-linking. They have devised partial
treatments, such as antioxidants and free-radical inhibitors. They
have proposed and studied other mechanisms of aging, such as
"clocks" in the cell and changes in the body's hormone balance. In
laboratory experiments, special drugs and diets have extended the
lifespan of mice by 25 to 45 percent.*(132)
Such work will continue; as the baby boom generation ages, expect
a boom in aging research. One biotechnology company, Senetek of
Denmark, specializes in aging research. In April 1985, Eastman
Kodak*(133) and ICN Pharmaceuticals were reported to have joined in
a $45 million venture to produce Isoprinosine and other drugs with the
potential to extend lifespan. The results of conventional antiaging
research may substantially lengthen human lifespans- and improve the
health of the old- during the next ten to twenty years. How greatly
will drugs, surgery, exercise, and diet extend lifespans? For now,
estimates must remain guesswork. Only new scientific knowledge can
rescue such predictions from the realm of speculation, because they
rely on new science*(134) and not just new engineering.
With cell repair machines, however, the potential for life extension
becomes clear. They will be able to repair cells so long as their
distinctive structures remain intact, and will be able to replace
cells that have been destroyed. Either way, they will restore
health. Aging is fundamentally no different from any other physical
disorder; it is no magical effect of calendar dates on a mysterious
life-force. Brittle bones, wrinkled skin, low enzyme activities,
slow wound healing, poor memory, and the rest all result from
damaged molecular machinery, chemical imbalances, and misarranged
structures. By restoring all the cells and tissues of the body to a
youthful structure, repair machines will restore youthful health.
People who survive intact until the time of cell repair machines
will have the opportunity to regain youthful health and to keep it
almost as long as they please. Nothing can make a person (or
anything else) last forever, of course, but barring severe
accidents, those wishing to do so will live for a long, long time.
As a technology develops, there comes a time when its principles
become clear, and with them many of its consequences. The principles
of rocketry were clear in the 1930s, and with them the consequence
of spaceflight. Filling in the details involved designing and
testing tanks, engines, instruments, and so forth. By the early 1950s,
many details were known. The ancient dream of flying to the Moon had
became a goal one could plan for.
The principles of molecular machinery are already clear, and with
them the consequence of cell repair machines. Filling in the details
will involve designing molecular tools, assemblers, computers, and
so forth, but many details of existing molecular machines are known
today. The ancient dream of achieving health and long life has
become a goal one can plan for.
Medical research is leading us, step by step, along a path toward
molecular machinery. The global competition to make better
materials, electronics, and biochemical tools is pushing us in the
same direction. Cell repair machines will take years to develop, but
they lie straight ahead.
They will bring many abilities, both for good and for ill. A
moment's thought about military replicators with abilities like
those of cell repair machines is enough to turn up nauseating
possibilities. Later I will describe how we might avoid such
horrors, but it first seems wise to consider the alleged benefits of
cell repair machines. Is their apparent good really good? How might
long life affect the world?
8
Long Life in an Open World
-
The long habit of living indisposeth us for dying.
-Sir THOMAS BROWNE
-
CELL REPAIR MACHINES raise questions involving the value of
extending human life. These are not the questions of today's medical
ethics, which commonly involve dilemmas posed by scarce, costly, and
half-effective treatments. They are instead questions involving the
value of long, healthy lives achieved by inexpensive means.
For people who value human life and enjoy living, such questions may
need no answer. But after a decade marked by concern about
population growth, pollution, and resource depletion, many people
may question the desirability of extending life; such concerns have
fostered the spread of pro-death memes. These memes must be examined
afresh, because many have roots in an obsolete worldview.
Nanotechnology will change far more than just human lifespan.
We will gain the means not only to heal ourselves, but to heal Earth
of the wounds we have inflicted. Since saving lives will increase
the number of the living, life extension raises questions about the
effect of more people. Our ability to heal the Earth will lessen one
cause for controversy.
Still, cell repair machines themselves will surely stir controversy.
They disturb traditional assumptions about our bodies and our futures:
this makes doubt soothing. They will require several major
breakthroughs: this makes doubt easy. Since the possibility or
impossibility of cell repair machines raises important issues, it
makes sense to consider what objections might be raised.
-
WHY NOT CELL REPAIR MACHINES?
-
What sort of argument could suggest that cell repair machines are
impossible? A successful argument must manage some strange
contortions. It must somehow hold that molecular machines cannot build
and repair cells, while granting that the molecular machines in our
bodies actually do build and repair cells every day. A cruel problem
for the committed skeptic! True, artificial machines must do what
natural machines fail to do, but they need not do anything
qualitatively novel. Both natural and artificial repair devices must
reach, identify, and rebuild molecular structures. We will be able
to improve on existing DNA repair enzymes simply by comparing
several DNA strands at once, so nature obviously hasn't found all
the tricks. Since this example explodes any general argument that
repair machines cannot improve on nature, a good case against cell
repair machines seems difficult to make.
Still, two general questions deserve direct answers. First, why
should we expect to achieve long life in the coming decades, when
people have tried and failed for millennia? Second, if we can indeed
use cell repair machines to extend lives, then why hasn't nature
(which has been repairing cells for billions of years) already
perfected them?
-
People have tried and failed.
For centuries, people have longed to escape their short lifespans.
Every so often, a Ponce de Leon or a quack doctor has promised a
potion, but it has never worked. These statistics of failure have
persuaded some people that, since all attempts have failed, all always
will fail. They say "Aging is natural," and to them that seems
reason enough. Medical advances may have shaken their views, but
advances have chiefly reduced early death, not extended maximum
lifespan.
But now biochemists have gone to work examining the machines that
build, repair, and control cells. They have learned to assemble
viruses and reprogram bacteria. For the first time in history,
people are examining their molecules and unraveling the molecular
secrets of life. It seems that molecular engineers will eventually
combine improved biochemical knowledge with improved molecular
machines, learning to repair damaged tissue structures and so
rejuvenate them. This is nothing strange- it would be strange, rather,
if such powerful knowledge and abilities did not bring dramatic
results. The massive statistics of past failure are simply irrelevant,
because we have never before tried to build cell repair machines.
-
Nature has tried and failed.
Nature has been building cell repair machines. Evolution has
tinkered with multicelled animals for hundreds of millions of years,
yet advanced animals all age and die, because nature's nanomachines
repair cells imperfectly. Why should improvements be possible?
Rats mature in months, and then age and die in about two years-
yet human beings have evolved to live over thirty times longer. If
longer lives were the chief goal of evolution, then rats would live
longer too. But durability has costs:*(135) to repair cells requires
an investment in energy, materials, and repair machines. Rat genes
direct rat bodies to invest in swift growth and reproduction, not in
meticulous self-repair. A rat that dallied in reaching breeding size
would run a greater risk of becoming a cat snack first. Rat genes have
prospered by treating rat bodies as cheap throwaways. Human genes
likewise discard human beings, though after a life a few dozen times
longer than a rat's.
But shoddy repairs are not the only cause of aging. Genes turn egg
cells into adults through a pattern of development which rolls forward
at fairly steady speed. This pattern is fairly consistent because
evolution seldom changes a basic design. Just as the basic pattern
of the DNA-RNA-protein system froze several billions of years ago,
so the basic pattern of chemical signals and tissue responses that
guides mammalian development jelled many millions of years ago. That
process apparently has a clock, set to run at different speeds in
different species, and a program that runs out.
Whatever the causes of aging, evolution has had little reason to
eliminate them. If genes built individuals able to stay healthy for
millennia, they would gain little advantage in their "effort" to
replicate. Most individuals would still die young from starvation,
predation, accident, or disease. As Sir Peter Medawar points
out,*(136) a gene that helps the young (who are many) but harms the
old (who are few) will replicate well and so spread through the
population. If enough such genes accumulate, animals become programmed
to die.
Experiments by Dr. Leonard Hayflick*(137) suggest that cells contain
"clocks" that count cell divisions and stop the division process
when the count gets too high. A mechanism of this sort*(138) can
help young animals: if cancer-like changes make a cell divide too
rapidly, but fail to destroy its clock, then it will grow to a tumor
of limited size. The clock would thus prevent the unlimited growth
of a true cancer. Such clocks could harm older animals by stopping the
division*(139) of normal cells, ending tissue renewal. The animal thus
would benefit from reduced cancer rates when young, yet have cause
to complain if it lives to grow old. But its genes won't listen-
they will have jumped ship earlier, as copies passed to the next
generation. With cell repair machines we will be able to reset such
clocks. Nothing suggests that evolution has perfected our bodies
even by the brute standard of survival and reproduction. Engineers
don't wire computers with slow, nervelike fibers or build machines out
of soft protein, and for good reason. Genetic evolution (unlike
memetic evolution) has been unable to leap to new materials or new
systems, but has instead refined and extended the old ones.
The cell's repair machines fall far short of the limits of the
possible- they don't even have computers to direct them. The lack of
nanocomputers in cells, of course, shows only that computers
couldn't (or simply didn't) evolve gradually from other molecular
machines. Nature has failed to build the best possible cell repair
machines, but there have been ample reasons.
-
HEALING AND PROTECTING THE EARTH
-
The failure of Earth's biological systems to adapt to the industrial
revolution is also easy to understand. From deforestation to dioxin,
we have caused damage faster than evolution can respond. As we have
sought more food, goods, and services, our use of bulk technology
has forced us to continue such damage. With future technology, though,
we will be able to do more good for ourselves, yet do less harm to the
Earth. In addition, we will be able to build planet-mending machines
to correct damage already done. Cells are not all we will want to
repair.
Consider the toxic waste problem. Whether in our air, soil, or
water, wastes concern us because they can harm living systems. But any
materials that come in contact with the molecular machinery of life
can themselves be reached by other forms of molecular machinery.
This means that we will be able to design cleaning machines to
remove these poisons*(140) wherever they could harm life.
Some wastes, such as dioxin, consist of dangerous molecules made
of innocuous atoms. Cleaning machines will render them harmless by
rearranging their atoms. Other wastes, such as lead and radioactive
isotopes, contain dangerous atoms. Cleaning machines will collect
these for disposal in any one of several ways. Lead comes from Earth's
rocks; assemblers could build it into rocks in the mines from which it
came. Radioactive isotopes could also be isolated from living
things, either by building them into stable rock or by more drastic
means. Using cheap, reliable space transportation systems, we could
bury them in the dead, dry rock of the Moon. Using nanomachines, we
could seal them in self-repairing, self-sealing containers the size of
hills and powered by desert sunlight. These would be more secure
than any passive rock or cask.
With replicating assemblers, we will even be able to remove the
billions of tons of carbon dioxide that our fuel-burning
civilization has dumped into the atmosphere. Climatologists project
that climbing carbon dioxide levels, by trapping solar energy, will
partially melt the polar caps, raising sea levels and flooding
coasts sometime in the middle of the next century. Replicating
assemblers, though, will make solar power cheap enough to eliminate
the need for fossil fuels.*(141) Like trees, solar-powered
nanomachines will be able to extract carbon dioxide from the air*(142)
and split off the oxygen. Unlike trees, they will be able to grow deep
storage roots and place carbon back in the coal seams and oil fields
from which it came.
Future planet-healing machines will also help us mend torn
landscapes and restore damaged ecosystems. Mining has scraped and
pitted the Earth; carelessness has littered it. Fighting forest
fires has let undergrowth thrive, replacing the cathedral-like
openness of ancient forests with scrub growth that feeds more
dangerous fires. We will use inexpensive, sophisticated robots to
reverse these effects and others. Able to move rock and soil, they
will recontour torn lands. Able to weed and digest, they will simulate
the clearing effects of natural forest fires without danger or
devastation. Able to lift and move trees, they will thin thick
stands and reforest bare hills. We will make squirrel-sized devices
with a taste for old trash. We will make treelike devices with roots
that spread deep and cleanse the soil of pesticides and excess acid.
We will make insect-sized lichen cleaners and spray-paint nibblers. We
will make whatever devices we need to clean up the mess left by
twentieth-century civilization.
After the cleanup, we will recycle most of these machines, keeping
only those we still need to protect the environment from a cleaner
civilization based on molecular technology. These more lasting devices
will supplement natural ecosystems wherever needed, to balance and
heal the effects of humanity. To make them effective, harmless, and
hidden will be a craft requiring not just automated engineering, but
knowledge of nature and a sense of art.
With cell repair technology, we will even be able to return some
species from apparent extinction. The African quagga- a zebralike
animal- became extinct over a century ago, but a salt-preserved quagga
pelt survived in a German museum. Alan Wilson of the University of
California at Berkeley and his co-workers*(143) have used enzymes to
extract DNA fragments from muscle tissue attached to this pelt. They
cloned the fragments in bacteria, compared them to zebra DNA, and
found (as expected) that the genes showed a close evolutionary
relationship. They have also succeeded in extracting and replicating
DNA from a century-old bison pelt and from millennia-old mammoths
preserved in the arctic permafrost. This success is a far cry from
cloning a whole cell or organism- cloning one gene leaves about
100,000 uncloned, and cloning every gene still doesn't repair a single
cell- but it does show that the hereditary material of these species
still survives.
As I described in the last chapter, machines that compare several
damaged copies of a DNA molecule will be able to reconstruct an
undamaged original- and the billions of cells in a dried skin
contain billions of copies. From these, we will be able to reconstruct
undamaged DNA, and around the DNA we will be able to construct
undamaged cells of whatever type we desire. Some insect species pass
through winter as egg cells, to be revived by the warmth of spring.
These "extinct" species will pass through the twentieth century as
skin and muscle cells, to be converted into fertile eggs and revived
by cell repair machines.
Dr. Barbara Durrant, a reproductive physiologist at the San Diego
Zoo, is preserving tissue samples from endangered species in a
cryogenic freezer. The payoff may be greater than most people now
expect. Preserving just tissue samples doesn't preserve the life of an
animal or an ecosystem, but it does preserve the genetic heritage of
the sampled species. We would be reckless if we failed to take out
this insurance policy against the permanent loss of species. The
prospect of cell repair machines thus affects our choices today.
Extinction is not a new problem. About 65 million years ago, most
then-existing species vanished, including all species of dinosaur.
In Earth's book of stone, the story of the dinosaurs ends on a page
consisting of a thin layer of clay. The clay is rich in iridium, an
element common in asteroids and comets. The best current theory
indicates that a blast from the sky smashed Earth's biosphere. With
the energy of a hundred million megatons of TNT, it spread dust and an
"asteroidal winter" planetwide.
In the eons since living cells first banded together to form
worms, Earth has suffered five great extinctions. Only 34 million
years ago- some 30 million years after the dinosaurs died- a layer
of glassy beads settled to the seafloor. Above that layer the
fossils of many species vanish. These beads froze from the molten
splash of an impact.
Meteor Crater, in Arizona, bears witness to a smaller, more recent
blast equaling that of a four-megaton bomb. As recently as June 30,
1908, a ball of fire split the Siberian sky and blasted the forest
flat across an area a hundred kilometers wide.
As people have long suspected, the dinosaurs died because they
were stupid. Not that they were too stupid to feed, walk, or guard
their eggs- they did survive for 140 million years- they were merely
too stupid to build telescopes able to detect asteroids and spacecraft
able to deflect them from collision with Earth. Space has more rocks
to throw at us, but we are showing signs of adequate intelligence to
deal with them. When nanotechnology and automated engineering give
us a more capable space technology, we will find it easy to track
and deflect asteroids; in fact, we could do it with technology
available today. We can both heal Earth and protect it.
-
LONG LIFE AND POPULATION PRESSURE
-
People commonly seek long, healthy lives, yet the prospect of a
dramatic success is unsettling. Might greater longevity harm the
quality of life? How will the prospect of long life affect our
immediate problems? Though most effects cannot be foreseen, some can.
For example, as cell repair machines extend life, they will increase
population. If all else were equal, more people would mean greater
crowding, pollution, and scarcity- but all else will not be equal: the
very advances in automated engineering and nanotechnology that will
bring cell repair machines will also help us heal the Earth, protect
it, and live more lightly upon it. We will be able to produce our
necessities and luxuries without polluting our air, land, or water. We
will be able to get resources and make things without scarring the
landscape with mines or cluttering it with factories. With efficient
assemblers making durable products, we will produce things of
greater value with less waste. More people will be able to live on
Earth, yet do less harm to it- or to one another, if we somehow manage
to use our new abilities for good ends.
If one were to see the night sky as a black wall and expect the
technology race to screech to a polite halt, then it would be
natural to fear that long-lived people would be a burden on the "poor,
crowded world of our children." This fear stems from the illusion that
life is a zero-sum game, that having more people always means
slicing a small pie thinner. But when we become able to repair
cells, we will also be able to build replicating assemblers and
excellent spacecraft. Our "poor" descendants will share a world the
size of the solar system, with matter, energy, and potential living
space dwarfing our entire planet.
This will open room enough for an era of growth and prosperity far
beyond any precedent. Yet the solar system itself is finite, and the
stars are distant. On Earth, even the cleanest assembler-based
industries will produce waste heat. Concern about population and
resources will remain important because the exponential growth of
replicators (such as people) can eventually overrun any finite
resource base.
But does this mean that we should sacrifice lives to delay the
crunch? A few people may volunteer themselves, but they will do little
good. In truth, life extension will have little effect on the basic
problem: exponential growth will remain exponential whether people die
young or live indefinitely. A martyr, by dying early, could delay
the crisis by a fraction of a second- but a halfway dedicated person
could help more by joining a movement of long-lived people working
to solve this long-range problem. After all, many people have
ignored the limits to growth on Earth. Who but the long-lived will
prepare for the firmer but more distant limits to growth in the
world beyond Earth? Those concerned with long-term limits will serve
humanity best by staying alive, to keep their concern alive.
Long life also raises the threat of cultural stagnation. If this
were an inevitable problem of long life, it is unclear what one
could do about it- machine-gun the old for holding firm opinions,
perhaps? Fortunately, two factors will reduce the problem somewhat.
First, in a world with an open frontier the young will be able to move
out, build new worlds, test new ideas, and then either persuade
their elders to change or leave them behind. Second, people old in
years will be young in body and brain. Aging slows both learning and
thought, as it slows other physical processes; rejuvenation will speed
them again. Since youthful muscles and sinews make young bodies more
flexible, perhaps youthful brain tissues will keep minds somewhat more
flexible, even when steeped in long years of wisdom.
-
THE EFFECTS OF ANTICIPATION
-
Long life will not be the greatest of the future's problems. It
might even help solve them.
Consider its effect on people's willingness to start wars. Aging and
death have made slaughter in combat more acceptable: As Homer had
Sarpedon, hero of Troy, say, "O my friend,*(144) if we, leaving this
war, could escape from age and death, I should not here be fighting in
the van; but now, since many are the modes of death impending over
us which no man can hope to shun, let us press on and give renown to
other men, or win it for ourselves."
Yet if the hope of escaping age and death turns people from
battle, will this be good? It might discourage small wars that could
grow into a nuclear holocaust. But equally, it might weaken our
resolve to defend ourselves from lifelong oppression- if we take no
account of how much more life we have to defend. The reluctance of
others to die for their ruler's power will help.
Expectations always shape actions. Our institutions and personal
plans both reflect our expectation that all adults now living will die
in mere decades. Consider how this belief inflames the urge to
acquire, to ignore the future in pursuit of a fleeting pleasure.
Consider how it blinds us to the future, and obscures the long-term
benefits of cooperation. Erich Fromm writes: "If the individual
lived five hundred or one thousand years, this clash (between his
interests and those of society) might not exist or at least might be
considerably reduced. He then might live and harvest with joy what
he sowed in sorrow; the suffering of one historical period which
will bear fruit in the next one could bear fruit for him too." Whether
or not most people will still live for the present is beside the
point: the question is, might there be a significant change for the
better?
The expectation of living a long life in a better future may well
make some political diseases less deadly. Human conflicts are far
too deep and strong to be uprooted by any simple change, yet the
prospect of vast wealth tomorrow may at least lessen the urge to fight
over crumbs today. The problem of conflict is great, and we need all
the help we can get.
The prospect of personal deterioration and death has always made
thoughts of the future less pleasant. Visions of pollution, poverty,
and nuclear annihilation have recently made thoughts of the future
almost too gruesome to bear. Yet with at least a hope of a better
future and time to enjoy it, we may look forward more willingly.
Looking forward, we will see more. Having a personal stake, we will
care more. Greater hope and foresight will benefit both the present
and posterity; they will even better our odds of survival.
Lengthened lives will mean more people, but without greatly
worsening tomorrow's population problem. The expectation of longer
lives in a better world will bring real benefits, by encouraging
people to give more thought to the future. Overall, long life and
its anticipation seem good for society, just as shortening lifespans
to thirty would be bad. Many people want long, healthy lives for
themselves. What are the prospects for the present generation?
-
PROGRESS IN LIFE EXTENSION
-
Hear Gilgamesh, King of Uruk:*(145)
-
"I have looked over the wall and I see the bodies floating on the
river, and that will be my lot also. Indeed I know it is so, for
whoever is tallest among men cannot reach the heavens, and the
greatest cannot encompass the earth."
-
Four millennia have passed since Sumerian scribes marked clay
tablets to record The Epic of Gilgamesh, and times have changed. Men
no taller than average have now reached the heavens and circled the
Earth. We of the Space Age, the Biotechnology Age, the Age of
Breakthroughs- need we still despair before the barrier of years? Or
will we learn the art of life extension soon enough to save
ourselves and those we love from dissolution?
The pace of biomedical advance holds tantalizing promise. The
major diseases of age- heart disease, stroke, and cancer- have begun
to yield to treatment. Studies of aging mechanisms have begun to
bear fruit, and researchers have extended animals' lifespans. As
knowledge builds on knowledge and tools lead to new tools, advances
seem sure to accelerate. Even without cell repair machines, we have
reason to expect major progress toward slowing and partially reversing
aging.
Although people of all ages will benefit from these advances, the
young will benefit more. Those surviving long enough will reach a time
when aging becomes fully reversible: at the latest, the time of
advanced cell repair machines. Then, if not sooner, people will grow
healthier as they grow older, improving like wine instead of
spoiling like milk. They will, if they choose, regain excellent health
and live a long, long time.
In that time, with its replicators and cheap spaceflight, people
will have both long lives and room and resources enough to enjoy them.
A question that may roll bitterly off the tongue is: "When?... Which
will be the last generation to age and die, and which the first to win
through?" Many people now share the quiet expectation that aging
will someday be conquered. But are those now alive doomed by a fluke
of premature birth? The answer will prove both clear and startling.
The obvious path to long life involves living long enough to be
rejuvenated by cell repair machines. Advances in biochemistry and
molecular technology will extend life, and in the time won they will
extend it yet more. At first we will use drugs, diet, and exercise
to extend healthy life. Within several decades, advances in
nanotechnology will likely bring early cell repair machines- and
with the aid of automated engineering, early machines may promptly
be followed by advanced machines. Dates must remain mere guesses,
but a guess will serve better than a simple question mark.
Imagine someone who is now thirty years old. In another thirty
years, biotechnology will have advanced greatly, yet that
thirty-year-old will be only sixty. Statistical tables which assume no
advances in medicine say that a thirty-year-old U.S. citizen can now
expect to live almost fifty more years- that is, well into the
2030s. Fairly routine advances (of sorts demonstrated in animals) seem
likely to add years, perhaps decades, to life by 2030. The mere
beginnings of cell repair technology might extend life by several
decades. In short, the medicine Of 2010, 2020, and 2030 seems likely
to extend our thirty-year-old's life into the 2040s or 2050s. By then,
if not before, medical advances may permit actual rejuvenation.
Thus, those under thirty (and perhaps those substantially older) can
look forward- at least tentatively- to medicine's overtaking their
aging process and delivering them safely to an era of cell repair,
vigor, and indefinite life-span.
If this were the whole story, then the division between the last
on the road to early death and the first on the road to long life
would be perhaps the ultimate gap between generations. What is more, a
gnawing uncertainty about one's own fate would give reason to push the
whole matter into the subconscious dungeon of disturbing speculations.
But is this really our situation? There seems to be another way to
save lives, one based on cell repair machines, yet applicable today.
As the last chapter described, repair machines will be able to heal
tissue so long as its essential structure is preserved. A tissue's
ability to metabolize and to repair itself becomes unimportant; the
discussion of biostasis illustrated this. Biostasis, as described,
will use molecular devices to stop function and preserve structure
by cross-linking the cell's molecular machines to one another.
Nanomachines will reverse biostasis by repairing molecular damage,
removing cross-links, and helping cells (and hence tissues, organs,
and the whole body) return to normal function.
Reaching an era with advanced cell repair machines seems the key
to long life and health, because almost all physical problems will
then be curable. One might manage to arrive in that era by remaining
alive and active through all the years between now and then- but
this is merely the most obvious way, the way that requires a minimum
of foresight. Patients today often suffer a collapse of heart function
while the brain structures that embody memory and personality remain
intact. In such cases, might not today's medical technology be able to
stop biological processes in a way that tomorrow's medical
technology will be able to reverse? If so, then most deaths are now
prematurely diagnosed, and needless.
9
A Door to the Future
-
London, April 1773.
-
To Jacques Dubourg.*(146)
-
Your observations on the causes of death, and the experiments
which you propose for recalling to life those who appear to be
killed by lightning, demonstrate equally your sagacity and your
humanity. It appears that the doctrine of life and death in general is
yet but little understood...
I wish it were possible... to invent a method of embalming drowned
persons, in such a manner that they might be recalled to life at any
period, however distant; for having a very ardent desire to see and
observe the state of America a hundred years hence, I should prefer to
an ordinary death, being immersed with a few friends in a cask of
Madeira, until that time, then to be recalled to life by the solar
warmth of my dear country! But... in all probability, we live in a
century too little advanced, and too near the infancy of science, to
see such an art brought in our time to its perfection...
I am, etc.
B. FRANKLIN.
-
BENJAMIN FRANKLIN wanted a procedure for stopping and restarting
metabolism, but none was then known. Do we live in a century far
enough advanced to make biostasis available- to open a future of
health to patients who would otherwise lack any choice but dissolution
after they have expired?
We can stop metabolism in many ways, but biostasis, to be of use,
must be reversible. This leads to a curious situation. Whether we
can place patients in biostasis using present techniques depends
entirely on whether future techniques will be able to reverse the
process. The procedure has two parts, of which we must master only
one.
If biostasis can keep a patient unchanged for years, then those
future techniques will include sophisticated cell repair systems. We
must therefore judge the success of present biostasis procedures in
light of the ultimate abilities of future medicine. Before cell repair
machines became a clear prospect, those abilities- and thus the
requirements for successful biostasis- remained grossly uncertain.
Now, the basic requirements seem fairly obvious.
-
THE REQUIREMENTS FOR BIOSTASIS
-
Molecular machines can build cells from scratch, as dividing cells
demonstrate. They can also build organs and organ systems from
scratch, as developing embryos demonstrate. Physicians will be able to
use cell repair technology to direct the growth of new organs from a
patient's own cells. This gives modern physicians great leeway in
biostasis procedures: even if they were to damage or discard most of a
patient's organs, they would still do no irreversible harm. Future
colleagues with better tools will be able to repair or replace the
organs involved. Most people would be glad to have a new heart,
fresh kidneys, or younger skin.*(147)
But the brain is another matter. A physician who allows the
destruction of a patient's brain allows the destruction of the patient
as a person, whatever may happen to the rest of the body. The brain
holds the patterns of memory, of personality, of self. Stroke patients
lose only parts of their brains, yet suffer harm ranging from
partial blindness to paralysis to loss of language, lowered
intelligence, altered personality, and worse. The effects depend on
the location of the damage. This suggests that total destruction of
the brain causes total blindness, paralysis, speechlessness, and
mindlessness, whether the body continues to breathe or not.
As Voltaire wrote, "To rise again- to be the same person that you
were- you must have your memory perfectly fresh and present; for it is
memory that makes your identity. If your memory be lost, how will
you be the same man?" Anesthesia interrupts consciousness without
disrupting the structure of the brain, and biostasis procedures must
do likewise, for a longer time. This raises the question of the nature
of the physical structures that underlie memory and personality.
Neurobiology, and informed common sense, agree on the basic nature
of memory. As we form memories and develop as individuals, our
brains change. These changes affect the brain's function, changing its
pattern of activity: When we remember, our brains do something; when
we act, think, or feel, our brains do something. Brains work by
means of molecular machinery. Lasting changes in brain function
involve lasting changes in this molecular machinery- unlike a
computer's memory, the brain is not designed to be wiped clean and
refilled at a moment's notice. Personality and long-term memory are
durable.
Throughout the body, durable changes in function involve durable
changes in molecular machinery. When muscles become stronger or
swifter, their proteins change in number and distribution. When a
liver adapts to cope with alcohol, its protein content also changes.
When the immune system learns to recognize a new kind of influenza
virus, protein content changes again. Since protein-based machines
do the actual work of moving muscles, breaking down toxins, and
recognizing viruses, this relationship is to be expected.
In the brain, proteins shape nerve cells, stud their surfaces,
link one cell to the next, control the ionic currents of each neural
impulse, produce the signal molecules that nerve cells use to
communicate across synapses, and much, much more. When printers
print words, they put down patterns of ink; when nerve cells change
their behavior, they change their patterns of protein. Printing also
dents the paper, and nerve cells change more than just their proteins,
yet the ink on the paper and the proteins in the brain are enough to
make these patterns clear. The changes involved are far from
subtle.*(148) Researchers report that long-term changes in nerve
cell behavior involve "striking morphological changes"*(149) in
synapses: they change visibly in size and structure.
It seems that long-term memory is not some terribly delicate
pattern, ready to evaporate from the brain at any excuse. Memory and
personality are instead firmly embodied in the way that brain cells
have grown together, in patterns formed through years of experience.
Memory and personality are no more material than the characters in a
novel; yet like them they are embodied in matter. Memory and
personality do not waft away on the last breath as a patient
expires. Indeed, many patients have recovered from so-called "clinical
death," even without cell repair machines to help. The patterns of
mind are destroyed only when and if the attending physicians allow the
patient's brain to undergo dissolution. This again allows physicians
considerable leeway in biostasis procedures: typically, they need
not stop metabolism until after vital functions have ceased.*(150)
It seems that preserving the cell structures and protein patterns of
the brain will also preserve the structure of the mind and self.
Biologists already know how to preserve tissue this well.
Resuscitation technology must await cell repair machines, but
biostasis technology seems well in hand.
-
METHODS OF BIOSTASIS
-
The idea that we already have biostasis techniques may seem
surprising, since powerful new abilities seldom spring up overnight.
In fact, the techniques are old- only understanding of their
reversibility is new. Biologists developed the two main approaches for
other reasons.
For decades, biologists have used electron microscopes to study
the structure of cells and tissues. To prepare specimens, they use a
chemical process called fixation to hold molecular structures in
place. A popular method uses glutaraldehyde molecules, flexible chains
of five carbon atoms with a reactive group of hydrogen and oxygen
atoms at each end. Biologists fix tissue by pumping a glutaraldehyde
solution through blood vessels, which allows glutaraldehyde
molecules to diffuse into cells. A molecule tumbles around inside a
cell until one end contacts a protein (or other reactive molecule) and
bonds to it. The other end then waves free until it, too, contacts
something reactive. This commonly shackles a protein molecule to a
neighboring molecule.
These cross-links lock molecular structures and machines in place;
other chemicals then can be added to do a more thorough or sturdy job.
Electron microscopy shows that such fixation procedures preserve
cells*(151) and the structures within them, including the cells and
structures of the brain.
The first step of the hypothetical biostasis procedure that I
described in Chapter 7 involved simple molecular devices able to enter
cells, block their molecular machinery, and tie structures together
with stabilizing cross-links. Glutaraldehyde molecules fit this
description quite well. The next step in this procedure involved other
molecular devices able to displace water and pack themselves solidly
around the molecules of a cell. This also corresponds to a known
process.
Chemicals such as propylene glycol, ethylene glycol, and dimethyl
sulfoxide can diffuse into cells, replacing much of their water yet
doing little harm. They are known as "cryoprotectants," because they
can protect cells from damage at low temperatures. If they replace
enough of a cell's water, then cooling doesn't cause freezing, it just
causes the protectant solution to become more and more viscous,
going from a liquid that resembles thin syrup in its consistency to
one that resembles hot tar, to one that resembles cold tar, to one
as resistant to flow as a glass, In fact, according to the
scientific definition of the term, the protectant solution then
qualifies as a glass; the process of solidification without
freezing*(152) is called vitrification. Mouse embryos*(153)
vitrified and stored in liquid nitrogen have grown into healthy mice.
The vitrification process packs the glassy protectant solidly around
the molecules of each cell; vitrification thus fits the description
I gave of the second stage of biostasis.
Fixation and vitrification together seem adequate to ensure
long-term biostasis. To reverse this form of biostasis, cell repair
machines will be programmed to remove the glassy protectant and the
glutaraldehyde cross-links and then repair and replace molecules, thus
restoring cells, tissues, and organs to working order.
Fixation with vitrification is not the first procedure proposed
for biostasis. In 1962 Robert Ettinger, a professor of physics at
Highland Park College in Michigan, published a book*(154) suggesting
that future advances in cryobiology might lead to techniques for the
easily reversible freezing of human patients. He further suggested
that physicians using future technology might be able to repair and
revive patients frozen with present techniques shortly after cessation
of vital signs. He pointed out that liquid nitrogen temperatures
will preserve patients for centuries, if need be, with little
change. Perhaps, he suggested, medical science will one day have
"fabulous machines" able to restore frozen tissue a molecule at a
time. His book gave rise to the cryonics movement.
Cryonicists have focused on freezing because many human cells revive
spontaneously*(155) after careful freezing and thawing. It is a common
myth that freezing bursts cells; in fact, freezing damage is more
subtle than this- so subtle that it often does no lasting harm. Frozen
sperm regularly produces healthy babies. Some human beings now alive
have survived being frozen solid at liquid nitrogen temperatures- when
they were early embryos. Cryobiologists are actively researching
ways to freeze and thaw viable organs*(156) to allow surgeons to store
them for later implantation.
The prospect of future cell repair technologies has been a
consistent theme*(157) among cryonicists. Still, they have tended to
focus on procedures that preserve cell function, for natural
reasons. Cryobiologists have kept viable human cells frozen for years.
Researchers have improved their results by experimenting with mixes of
cryoprotective chemicals and carefully controlled cooling and
warming rates. The complexities of cryobiology offer rich
possibilities for further experimentation. This combination of
tangible, tantalizing success and promising targets for further
research has made the quest for an easily reversible freezing
process a vivid and attractive goal for cryonicists. A success at
freezing and reviving an adult mammal would be immediately visible and
persuasive.
What is more, even partial preservation of tissue function
suggests excellent preservation of tissue structure. Cells that can
revive (or almost revive) even without special help will need little
repair.
The cryonics community's cautious, conservative emphasis on
preserving tissue function has invited public confusion, though.
Experimenters have frozen whole adult mammals and thawed them
without waiting for the aid of cell repair machines. The results
have been superficially discouraging: the animals fail to
revive.*(158) To a public and a medical community that has known
nothing about the prospects for cell repair, this has made frozen
biostasis seem pointless.
And, after Ettinger's proposal, a few cryobiologists chose to make
unsupported pronouncements about the future of medical technology.
As Robert Prehoda stated*(159) in a 1967 book: "Almost all
reduced-metabolism experts... believe that cellular damage caused by
current freezing techniques could never be corrected." Of course,
these were the wrong experts to ask. The question called for experts
on molecular technology and cell repair machines. These cryobiologists
should have said only that correcting freezing damage would apparently
require molecular-level repairs, and that they, personally, had not
studied the matter. Instead, they casually misled the public on a
matter of vital medical importance. Their statements discouraged the
use of a workable biostasis technique.*(160)
Cells are mostly water. At low enough temperatures, water
molecules join to form a weak but solid framework of cross-links.
Since this preserves neural structures*(161) and thus the patterns
of mind and memory, Robert Ettinger has apparently identified a
workable approach to biostasis. As molecular technology advances and
people grow familiar with its consequences, the reversibility of
biostasis (whether based on freezing, fixation and vitrification, or
other methods) will grow ever more obvious to ever more people.
-
REVERSING BIOSTASIS
-
Imagine that a patient has expired because of a heart attack.
Physicians attempt resuscitation but fail, and give up on restoring
vital functions. At this point, though, the patient's body and brain
are just barely nonfunctional- most cells and tissues, in fact, are
still alive and metabolizing. Having made arrangements beforehand, the
patient is soon placed in biostasis to prevent irreversible
dissolution and await a better day.
Years pass. The patient changes little, but technology advances
greatly. Biochemists learn to design proteins. Engineers use protein
machines to build assemblers, then use assemblers to build a
broad-based nanotechnology. With new instruments, biological knowledge
explodes. Biomedical engineers use new knowledge, automated
engineering, and assemblers to develop cell repair machines of growing
sophistication. They learn to stop and reverse aging. Physicians use
cell repair technology to resuscitate patients in biostasis- first
those placed in biostasis by the most advanced techniques, then
those placed in biostasis using earlier and cruder techniques.
Finally, after the successful resuscitation of animals placed in
biostasis using the old techniques of the 1980s, physicians turn to
our heart-attack patient.
In the first stage of preparation, the patient lies in a tank of
liquid nitrogen surrounded by equipment. Glassy protectant still locks
each cell's molecular machinery in a firm embrace. This protectant
must be removed, but simple warming might allow some cell structures
to move about prematurely.
Surgical devices designed for use at low temperatures reach
through the liquid nitrogen to the patient's chest. There they
remove solid plugs of tissue to open access to major arteries and
veins. An army of nanomachines equipped for removing protectant
moves through these openings, clearing first the major blood
vessels*(162) and then the capillaries. This opens paths throughout
the normally active tissues*(163) of the patient's body. The larger
surgical machines then attach tubes to the chest and pump fluid
through the circulatory system. The fluid washes out the initial
protectant-removal machines (later, it supplies materials to repair
machines and carries away waste heat).
Now the machines pump in a milky fluid containing trillions of
devices that enter cells and remove the glassy protectant,*(164)
molecule by molecule. They replace it with a temporary molecular
scaffolding*(165) that leaves ample room for repair machines to
work. As these protectant-removal machines uncover biomolecules,
including the structural and mechanical components of the cells,
they bind them to the scaffolding with temporary cross-links. (If
the patient had also been treated with a cross-linking fixative, these
cross-links would now be removed and replaced with the temporary
links.) When molecules must be moved aside, the machines label
them*(166) for proper replacement. Like other advanced cell repair
machines, these devices work under the direction of on-site
nanocomputers.
When they finish, the low-temperature machines withdraw. Through a
series of gradual changes in composition and temperature, a
water-based solution replaces the earlier cryogenic fluid and the
patient warms to above the freezing point. Cell repair machines are
pumped through the blood vessels and enter the cells. Repairs
commence.
Small devices examine molecules and report their structures and
positions to a larger computer within the cell.*(167) The computer
identifies the molecules, directs any needed molecular repairs, and
identifies cell structures from molecular patterns.*(168) Where damage
has displaced structures in a cell, the computer directs the repair
devices to restore the molecules to their proper arrangement, using
temporary cross-links as needed. Meanwhile, the patient's arteries are
cleared and the heart muscle, damaged years earlier, is repaired.
Finally, the molecular machinery of the cells has been restored to
working order, and coarser repairs have corrected damaged patterns
of cells to restore tissues and organs to a healthy condition. The
scaffolding is then removed from the cells, together with most of
the temporary cross-links and much of the repair machinery. Most of
each cell's active molecules remain blocked, though, to prevent
premature, unbalanced activity.
Outside the body, the repair system has grown fresh blood from the
patient's own cells. It now transfuses this blood to refill the
circulatory system, and acts as a temporary artificial heart. The
remaining devices in each cell now adjust the concentration of
salts, sugars, ATP, and other small molecules, largely by
selectively unblocking each cell's own nanomachinery. With further
unblocking, metabolism resumes step by step; the heart muscle is
finally unblocked on the verge of contraction. Heartbeat resumes,
and the patient emerges into a state of anesthesia. While the
attending physicians check that all is going well, the repair system
closes the opening in the chest, joining tissue to tissue without a
stitch or a scar. The remaining devices in the cells disassemble one
another into harmless waste or nutrient molecules. As the patient
moves into ordinary sleep, certain visitors enter the room, as long
planned.
At last, the sleeper wakes refreshed to the light of a new day-
and to the sight of old friends.
-
MIND, BODY, AND SOUL
-
Before considering resuscitation, however, some may ask what becomes
of the soul of a person in biostasis. Some people would answer that
the soul and the mind are aspects of the same thing, of a pattern
embodied in the substance of the brain, active during active life
and quiescent in biostasis. Assume, though, that the pattern of
mind, memory, and personality leaves the body at death, carried by
some subtle substance. The possibilities then seem fairly clear. Death
in this case has a meaning other than irreversible damage to the
brain, being defined instead by the irreversible departure of the
soul. This would make biostasis a pointless but harmless gesture-
after all, religious leaders have expressed no concern that mere
preservation of the body can somehow imprison a soul. Resuscitation
would, in this view, presumably require the cooperation of the soul to
succeed. The act of placing patients in biostasis has in fact been
accompanied by both Catholic and Jewish ceremonies.
With or without biostasis, cell repair cannot bring immortality.
Physical death, however greatly postponed, will remain inevitable
for reasons rooted in the nature of the universe. Biostasis followed
by cell repair thus seems to raise no fundamental theological
issues. It resembles deep anesthesia followed by life-saving
surgery: both procedures interrupt consciousness to prolong life. To
speak of "immortality" when the prospect is only long life would be to
ignore the facts or to misuse words.
-
REACTIONS AND ARGUMENTS
-
The prospect of biostasis seems tailor-made to cause future shock.
Most people find today's accelerating change shocking enough when it
arrives a bit at a time. But the biostasis option is a present-day
consequence of a whole series of future breakthroughs. This prospect
naturally upsets the difficult psychological adjustments that people
make in dealing with physical decline.
Thus far, I have built the case for cell repair and biostasis on a
discussion of the commonplace facts of biology and chemistry. But what
do professional biologists think about the basic issues? In
particular, do they believe (1) that repair machines will be able to
correct the kind of cross-linking damage produced by fixation, and (2)
that memory is indeed embodied in a preservable form?
After a discussion of molecular machines and their capabilities- a
discussion not touching on medical implications- Dr. Gene Brown,
professor of biochemistry and chairman of the department of biology at
MIT, gave permission to be quoted as stating that: "Given sufficient
time and effort to develop artificial molecular machines and to
conduct detailed studies of the molecular biology of the cell, very
broad abilities should emerge. Among these could be the ability to
separate the proteins (or other biomolecules) in cross-linked
structures, and to identify, repair, and replace them." This statement
addresses a significant part of the cell repair problem. It was
consistently endorsed by a sample of biochemists and molecular
biologists at MIT and Harvard after similar discussions.
After a discussion of the brain and the physical nature of memory
and personality- again, a discussion not touching on medical
implications- Dr. Walle Nauta (Institute Professor of Neuroanatomy
at MIT) gave permission to be quoted as stating that: "Based on our
present knowledge of the molecular biology of neurons, I think most
would agree that the changes produced during the consolidation of
long-term memory are reflected in corresponding changes in the
number and distribution of different protein molecules in the
neurons of the brain." Like Dr. Brown's statement, this addresses a
key point regarding the workability of biostasis. It, too, was
consistently endorsed by other experts when discussed in a context
that insulated the experts from any emotional bias that might result
from the medical implications of the statement. Further, since these
points relate directly to their specialties, Dr. Brown and Dr. Nauta
were appropriate experts to ask.
It seems that the human urge to live will incline many millions of
people toward using biostasis (as a last resort) if they consider it
workable. As molecular technology advances, understanding of cell
repair will spread through the popular culture. Expert opinion will
increasingly support the idea. Biostasis will grow more common, and
its costs will fall. It seems likely that many people will
eventually consider biostasis to be the norm, to be a standard
lifesaving treatment for patients who have expired.
But until cell repair machines are demonstrated, the all too human
tendency to ignore what we haven't seen will slow the acceptance of
biostasis. Millions will no doubt pass from expiration to irreversible
dissolution because of habit and tradition, supported by weak
arguments. The importance of clear foresight in this matter makes it
important to consider possible arguments before leaving the topic of
life extension and moving on to other matters. Why, then, might
biostasis not seem a natural, obvious idea?
-
Because cell repair machines aren't here yet.
-
It may seem strange to save a person from dissolution in the
expectation of restoring health, since the repair technology doesn't
exist yet. But is this so much stranger than saving money to put a
child through college? After all, the college student doesn't exist
yet, either. Saving money makes sense because the child will mature;
saving a person makes sense because molecular technology will mature.
We expect a child to mature because we have seen many children
mature; we can expect this technology to mature because we have seen
many technologies mature. True, some children suffer from congenital
shortcomings, as do some technologies, but experts often can
estimate the potential of children or technologies while they remain
young.
Microelectronic technology started with a few spots and wires on a
chip of silicon, but grew into computers on chips. Physicists such
as Richard Feynman saw,*(169) in part, how far it would lead.
Nuclear technology started with a few atoms splitting in the
laboratory under neutron bombardment, but grew into billion-watt
reactors and nuclear bombs. Leo Szilard saw, in part, how far it would
lead.
Liquid rocket technology started with crude rockets launched from
a Massachusetts field, but grew into Moonships and space shuttles.
Robert Goddard saw, in part, how far it would lead.
Molecular engineering has started with ordinary chemistry and
molecular machines borrowed from cells, but it, too, will grow mighty.
It, too, has discernible consequences.
-
Because tiny machines lack drama.
-
We tend to expect dramatic results only from dramatic causes, but
the world often fails to cooperate. Nature delivers both triumph and
disaster in brown paper wrappers.
-
DULL FACT: Certain electric switches can turn one another on and
off. These switches can be made very small, and frugal of electricity.
THE DRAMATIC CONSEQUENCE: When properly connected, these switches
form computers, the engines of the information revolution.
-
DULL FACT: Ether is not too poisonous, yet temporarily interferes
with the activity of the brain.
THE DRAMATIC CONSEQUENCE: An end to the agony of surgery on
conscious patients, opening a new era in medicine.
-
DULL FACT: Molds and bacteria compete for food, so some molds have
evolved to secrete poisons that kill bacteria.
THE DRAMATIC CONSEQUENCE: Penicillin, the conquest of many bacterial
diseases, and the saving of millions of lives.
-
DULL FACT: Molecular machines can be used to handle molecules and
build mechanical switches of molecular size.
THE DRAMATIC CONSEQUENCE: Computer-directed cell repair machines,
bringing cures for virtually all diseases.
-
DULL FACT: Memory and personality are embodied in preservable
brain structures.
THE DRAMATIC CONSEQUENCE: Present techniques can prevent
dissolution, letting the present generation take advantage of
tomorrow's cell repair machines.
-
In fact, molecular machines aren't even so dull. Since tissues are
made of atoms, one should expect a technology able to handle and
rearrange atoms to have dramatic medical consequences.
-
Because this seems too incredible.
-
We live in a century of the incredible.
In an article entitled "The Idea of Progress" in Astronautics and
Aeronautics, aerospace engineer Robert T. Jones wrote:*(170) "In 1910,
the year I was born, my father was a prosecuting attorney. He traveled
all the dirt roads in Macon County in a buggy behind a single horse.
Last year I flew nonstop from London to San Francisco over the polar
regions, pulled through the air by engines of 50,000 horsepower." In
his father's day, such aircraft lay at the fringe of science
fiction, too incredible to consider.
In an article entitled "Basic Medical Research: A Long-Term
Investment" in MIT's Technology Review, Dr. Lewis Thomas
wrote:*(171) "Forty years ago, just before the profession underwent
transformation from an art to science and technology, it was taken for
granted that the medicine we were being taught was precisely the
medicine that would be with us for most of our lives. If anyone had
tried to tell us that the power to control bacterial infections was
just around the corner, that open-heart surgery or kidney
transplants would be possible within a couple of decades, that some
kinds of cancer could be cured by chemotherapy, and that we would soon
be within reach of a comprehensive, biochemical explanation for
genetics and genetically determined diseases, we would have reacted in
blank disbelief. We had no reason to believe that medicine would
ever change.... What this recollection suggests is that we should keep
our minds wide open in the future."
-
Because this sounds too good to be true.
-
News of a way to avoid the fatality of most fatal diseases may
indeed sound too good to be true- as it should, since it is but a
small part of a more balanced story. In fact, the dangers of molecular
technology roughly balance its promise. In Part Three I will outline
reasons for considering nanotechnology more dangerous than nuclear
weapons.
Fundamentally, though, nature cares nothing for our sense of good
and bad and nothing for our sense of balance. In particular, nature
does not hate human beings enough to stack the deck against us.
Ancient horrors have vanished before.
Years ago, surgeons strove to amputate legs fast. Robert Liston of
Edinburgh, Scotland, once sawed through a patient's thigh in a
record thirty-three seconds, removing three of his assistant's fingers
in the process. Surgeons worked fast to shorten their patients' agony,
because their patients remained conscious.
If terminal illness without biostasis is a nightmare today, consider
surgery without anesthesia in the days of our ancestors: the knife
slicing through flesh, the blood flowing, the saw grating on the
bone of a conscious patient.... Yet in October of 1846, W. T. G.
Morton and J. C. Warren removed a tumor from a patient under ether
anesthesia; Arthur Slater states that their success "was rightly
hailed as the great discovery of the age." With simple techniques
based on a known chemical, the waking nightmare of knife and saw at
long last was ended.
With agony ended, surgery increased, and with it surgical
infection and the horror of routine death from flesh rotting in the
body. Yet in 1867 Joseph Lister published*(172) the results of his
experiments with phenol, establishing the principles of antiseptic
surgery. With simple techniques based on a known chemical, the
nightmare of rotting alive shrank dramatically.
Then came sulfa drugs and penicillin, which ended many deadly
diseases in a single blow... the list goes on.
Dramatic medical breakthroughs have come before, sometimes from
new uses of known chemicals, as in anesthesia and antiseptic
surgery. Though these advances may have seemed too good to be true,
they were true nonetheless. Saving lives by using known chemicals
and procedures to produce biostasis can likewise be true.
-
Because doctors don't use biostasis today.
-
Robert Ettinger proposed a biostasis technique in 1962. He states
that Professor Jean Rostand had proposed the same approach years
earlier, and had predicted its eventual use in medicine. Why did
biostasis by freezing fail to become popular? In part because of its
initial expense, in part because of human inertia, and in part because
means for repairing cells remained obscure. Yet the ingrained
conservatism of the medical profession has also played a role.
Consider again the history of anesthesia.
In 1846, Morton and Warren amazed the world with the "discovery of
the age," ether anesthesia. Yet two years earlier, Horace Wells had
used nitrous oxide anesthesia, and two years before that, Crawford
W. Long had performed an operation using ether. In 1824, Henry Hickman
had successfully anesthetized animals using ordinary carbon dioxide;
he later spent years urging surgeons in England and France to test
nitrous oxide as an anesthetic. In 1799, a full forty-seven years
before the great "discovery," and years before Liston's assistant lost
his fingers, Sir Humphry Davy wrote:*(173) "As nitrous oxide in its
extensive operation appears capable of destroying physical pain, it
may possibly be used during surgical operations."
Yet as late as 1839 the conquest of pain still seemed an
impossible dream to many physicians. Dr. Alfred Velpeau stated: "The
abolishment of pain in surgery is a chimera. It is absurd to go on
seeking it today. 'Knife' and 'pain' are two words in surgery that
must forever be associated in the consciousness of the patient. To
this compulsory combination we shall have to adjust ourselves."
Many feared the pain of surgery more than death itself. Perhaps
the time has come to awaken from the final medical nightmare.
-
Because it hasn't been proved to work.
-
It is true that no experiment can now demonstrate the
resuscitation of a patient in biostasis. But a demand for such a
demonstration would carry the hidden assumption that modern medicine
has neared the final limits of the possible, that it will never be
humbled by the achievements of the future. Such a demand might sound
cautious and reasonable, but in fact it would smack of overwhelming
arrogance.
Unfortunately, a demonstration is exactly what physicians have
been trained to request, and for good reason: they wish to avoid
useless procedures that may do harm. Perhaps it will suffice that
neglect of biostasis leads to obvious and irreversible harm.
-
TIME, COST, AND HUMAN ACTION
-
Whether people choose to use biostasis will depend on whether they
see it as worth the gamble. This gamble involves the value of life
(which is a personal matter), the cost of biostasis (which seems
reasonable by the standards of modern medicine), the odds that the
technology will work (which seem excellent), and the odds that
humanity will survive, develop the technology, and revive people. This
final point accounts for most of the overall uncertainty.
Assume that human beings and free societies will indeed survive. (No
one can calculate the odds of this, but to assume failure would
discourage the very efforts that will promote success.) If so, then
technology will continue to advance. Developing assemblers will take
years. Studying cells and learning to repair the tissues of patients
in biostasis will take still longer. At a guess, developing repair
systems and adapting them to resuscitation will take three to ten
decades, though advances in automated engineering may speed the
process.
The time required seems unimportant, however. Most resuscitated
patients will care more about the conditions of life- including the
presence of their friends and family- than they will care about the
date on the calendar. With abundant resources, the physical conditions
of life could be very good indeed. The presence of companions is
another matter.
In a recently published survey, over half of those responding said
that they would like to live for at least five hundred years, if given
a free choice. Informal surveys show that most people would prefer
biostasis to dissolution, if they could regain good health and explore
a new future with old companions. A few people say that they "want
to go when their time comes," but they generally agree that, so long
as they can choose further life, their time has not yet come. It seems
that many people today share Benjamin Franklin's desire, but in a
century able to satisfy it. If biostasis catches on fast enough (or if
other life-extension technologies advance fast enough), then a
resuscitated patient will awake not to a world of strangers, but to
the smiles of familiar faces.
But will people in biostasis be resuscitated? Techniques for placing
patients in biostasis are already known, and the costs could become
low, at least compared to the costs of major surgery or prolonged
hospital care. Resuscitation technology, though, will be complex and
expensive to develop. Will people in the future bother?
It seems likely that they will. They may not develop
nanotechnology with medicine in mind- but if not, then they will
surely develop it to build better computers. They may not develop cell
repair machines with resuscitation in mind, but they will surely do so
to heal themselves. They may not program repair machines for
resuscitation as an act of impersonal charity, but they will have
time, wealth, and automated engineering systems, and some of them will
have loved ones waiting in biostasis. Resuscitation techniques seem
sure to be developed.
With replicators and space resources, a time will come when people
have wealth and living space over a thousandfold greater than we
have today. Resuscitation itself will require little energy and
material even by today's standards. Thus, people contemplating
resuscitation will find little conflict between their self-interest
and their humanitarian concerns. Common human motives seem enough to
ensure that the active population of the future will awaken those in
biostasis.
The first generation that will regain youth without being forced
to resort to biostasis may well be with us today. The prospect of
biostasis simply gives more people more reason to expect long life- it
offers an opportunity for the old and a form of insurance for the
young. As advances in biotechnology lead toward protein design,
assemblers, and cell repair, and as the implications sink in, the
expectation of long life will spread. By broadening the path to long
life, the biostasis option will encourage a more lively interest in
the future. And this will spur efforts to prepare for the dangers
ahead.
10
The Limits to Growth
-
The chess board is the world, the pieces are the phenomena of the
universe, the rules of the game are what we call the laws of nature.
-T. H. HUXLEY
-
IN THE LAST CENTURY we have developed aircraft, spacecraft,
nuclear power, and computers. In the next we will develop
assemblers, replicators, automated engineering, cheap spaceflight,
cell repair machines, and much more. This series of breakthroughs
may suggest that the technology race will advance without limit. In
this view, we will break through all conceivable barriers, rushing off
into the infinite unknown- but this view seems false.
The laws of nature and the conditions of the world will limit what
we do. Without limits, the future would be wholly unknown, a
formless thing making a mockery of our efforts to think and plan. With
limits, the future is still a turbulent uncertainty, but it is
forced to flow within certain bounds.
From natural limits, we learn something about the problems and
opportunities we face. Limits define the boundaries of the possible,
telling us what resources we can use, how fast our spacecraft will
fly, and what our nanomachines will and won't be able to do.
Discussing limits is risky: we can be more sure that something is
possible than that it isn't. Engineers can make do with approximations
and special cases. And given tools, materials, and time, they can
demonstrate possibilities directly. Even when doing exploratory
design, they can stay well within the realm of the possible by staying
well away from the limits. Scientists, in contrast, cannot prove a
general theory- and every general claim of impossibility is itself a
sort of general theory. No specific experiment (someplace, sometime)
can prove something to be impossible (everywhere, forever). Neither
can any number of specific experiments.
Still, general scientific laws do describe limits to the possible.
Although scientists cannot prove a general law, they have evolved
our best available picture of how the universe works. And even if
exotic experiments and elegant mathematics again transform our concept
of physical law, few engineering limits will budge. Relativity
didn't affect automobile designs.
The mere existence of ultimate limits doesn't mean that they are
about to choke us, yet many people have been drawn to the idea that
limits will end growth soon. This notion simplifies their picture of
the future by leaving out the strange new developments that growth
will bring. Other people favor the vaguer notion of limitless
growth- a notion that blurs their picture of the future by
suggesting that it will be utterly incomprehensible.
People who confuse science with technology tend to become confused
about limits. As software engineer Mark S. Miller points out, they
imagine that new knowledge always means new know-how; some even
imagine that knowing everything would let us do anything. Advances
in technology do indeed bring new know-how, opening new possibilities.
But advances in basic science simply redraw our map of ultimate
limits; this often shows new impossibilities. Einstein's
discoveries, for example, showed that nothing can catch up with a
fleeing light ray.
-
THE STRUCTURE OF THE VACUUM
-
Is the speed of light a real limit? People once spoke of a "sound
barrier" that some believed would stop an airplane from passing the
speed of sound. Then at Edwards Air Force Base in 1947, Chuck Yeager
split the October sky with a sonic boom. Today, some people speak of a
"light barrier," and ask whether it, too, may fall.
Unfortunately for science fiction writers, this parallel is
superficial. No one could ever maintain that the speed of sound was
a true physical limit. Meteors and bullets exceeded it daily, and even
cracking whips cracked the "sound barrier." But no one has seen
anything move faster than light. Distant spots seen by radio
telescopes sometimes appear to move faster, but simple tricks of
perspective easily explain how this can be. Hypothetical particles
called "tachyons" would move faster than light, if they were to exist-
but none has been found, and current theory doesn't predict them.
Experimenters have pushed protons to over 99.9995 percent of the speed
of light, with results that match Einstein's predictions perfectly.
When pushed ever faster, a particle's speed creeps closer to the speed
of light, while its energy (mass) grows without bound.
On Earth, a person can walk or sail only to a certain distance,
but no mysterious edge or barrier suddenly blocks travel. The Earth is
simply round. The speed limit in space no more implies a "light
barrier" than the distance limit on Earth implies a wall. Space
itself- the vacuum that holds all energy and matter- has properties.
One of these is its geometry, which can be described by regarding time
as a special dimension. This geometry makes the speed of light
recede before an accelerating spaceship much as the horizon recedes
before a moving sea ship: the speed of light, like the horizon, is
always equally remote in all directions. But the analogy dies here-
this similarity has nothing to do with the curvature of space. It is
enough to remember that the limiting speed is nothing so crude or so
breakable*(174) as a "light barrier." Objects can always go faster,
just no faster than light.
People have long dreamed of gravity control. In the 1962 edition
of Profiles of the Future, Arthur C. Clarke wrote*(175) that "Of all
the forces, gravity is the most mysterious and the most implacable,"
and then went on to suggest that we will someday develop convenient
devices for controlling gravity. Yet is gravity really so
mysterious? In the general theory of relativity, Einstein described
gravity as curvature in the space-time structure of the vacuum. The
mathematics describing this is elegant and precise, and it makes
predictions that have passed every test yet contrived.
Gravity is neither more nor less implacable than other forces. No
one can make a boulder lose its gravity, but neither can anyone make
an electron lose its electric charge or a current its magnetic
field. We control electric and magnetic fields by moving the particles
that create them; we can control gravitational fields similarly, by
moving ordinary masses. It seems that we cannot learn the secret of
gravity control because we already have it.
A child with a small magnet can lift a nail, using a magnetic
field to overwhelm Earth's gravitational pull. But unfortunately for
eager gravitational engineers, using gravity to lift a nail requires a
tremendous mass. Hanging Venus just over your head would almost do the
job- until it fell on you.
Engineers stir up electromagnetic waves by shaking electric
charges back and forth in an antenna; one can stir up gravity waves by
shaking a rock in the air. But again, the gravitational effect is
weak. Though a one-kilowatt radio station is nothing extraordinary,
all the shaking and spinning of all the masses in the solar system put
together fails to radiate as much as a kilowatt of gravity waves.
We understand gravity well enough; it simply isn't much use in
building machines much lighter than the Moon. But devices using
large masses do work. A hydroelectric dam is part of a gravity machine
(the other part being the Earth) that extracts energy from falling
mass. Machines using black holes will be able to extract energy from
falling mass with over fifty percent efficiency, based on E=mc(2).
Lowering a single bucket of water into a black hole would yield as
much energy as pouring several trillion buckets of water through the
generators of a kilometer-high dam.
Because the laws of gravity describe how the vacuum curves, they
also apply to science-fiction style "space warps." It seems that
tunnels from one point in space to another would be unstable, even
if they could be created in the first place. This prevents future
spaceships from reaching distant points faster than light by taking
a shortcut around the intervening space, and this limit to travel in
turn sets a limit to growth.
Einstein's laws seem to give an accurate description of the
overall geometry of the vacuum. If so, then the limits that result
seem inescapable: you can get rid of almost anything, but not the
vacuum itself.
Other laws and limits seem inescapable for similar reasons. In fact,
physicists have increasingly come to regard all of physical law in
terms of the structure of the vacuum. Gravity waves are a certain kind
of ripple in the vacuum; black holes are a certain kind of kink.
Likewise, radio waves are another kind of ripple in the vacuum, and
elementary particles are other, very different kinds of kinks (which
in some theories resemble tiny, vibrating strings). In this view,
there is only one substance in the universe- the vacuum- but one
that takes on a variety of forms, including those patterns of
particles that we call "solid matter." This view suggests the
inescapable quality of natural law. If a single substance fills the
universe, is the universe, then its properties limit all that we can
do.*(176)
The strangeness of modern physics, however, leads many people to
distrust it. The revolutions that brought quantum mechanics and
relativity gave rise to talk of "the uncertainty principle," "the wave
nature of matter," "matter being energy," and "curved space-time."
An air of paradox surrounds these ideas and thus physics itself. It is
understandable that new technologies should seem odd to us, but why
should the ancient and immutable laws of nature turn out to be bizarre
and shocking?
Our brains and languages evolved to deal with things vastly larger
than atoms, moving at a tiny fraction of the speed of light. They do a
tolerable job of this, though it took people centuries to learn to
describe the motion of a falling rock. But we have now stretched our
knowledge far beyond the ancient world of the senses. We have found
things (matter waves, curved space) that seem bizarre- and some that
are simply beyond our ability to visualize. But "bizarre" does not
mean mysterious and unpredictable. Mathematics and experiments still
work, letting scientists vary and select theories, evolving them to
fit even a peculiar reality. Human minds have proved remarkably
flexible, but it is no great surprise to find that we cannot always
visualize the invisible.
Part of the reason that physics seems so strange is that people
crave oddities, and tend to spread memes that describe things as
odd. Some people favor ideas that coat the world in layers of ghost
stuff and fill it with grade-B mysteries. Naturally, they favor and
spread memes that make matter seem immaterial and quantum mechanics
seem like a branch of psychology.
Relativity, it is said, reveals that matter (that plain old stuff
that people think they understand) is really energy (that subtle,
mysterious stuff that makes things happen). This encourages a
smiling vagueness about the mystery of the universe. It might be
clearer to say that relativity reveals energy to be a form of
matter: in all its forms, energy has mass. Indeed, lightsails work
on this principle, through the impact of mass on a surface. Light even
comes packaged in particles.
Consider also the Heisenberg uncertainty principle, and the
related fact that "the observer always affects the observed." The
uncertainty principle is intrinsic to the mathematics describing
ordinary matter (giving atoms their very size), but the associated
"effect of the observer" has been presented in some popular books as a
magical influence of consciousness on the world. In fact, the core
idea is more prosaic. Imagine looking at a dust mote in a light
beam: When you observe the reflected light, you certainly affect it-
your eye absorbs it. Likewise, the light (with its mass) affects the
dust mote: it bounces off the mote, exerting a force. The result is
not an effect of your mind on the dust, but of the light on the
dust. Though quantum measurement has peculiarities far more
subtle*(177) than this, none involves the mind reaching out to
change reality.
Finally, consider the "twin paradox." Relativity predicts that, if
one of a pair of twins flies to another star and back at near the
speed of light, the traveling twin will be younger than the
stay-at-home twin. Indeed, measurements with accurate clocks
demonstrate the time-slowing effect of rapid motion. But this is not a
"paradox"; it is a simple fact of nature.
-
WILL PHYSICS AGAIN BE UPENDED?
-
In 1894 the eminent physicist Albert A. Michelson stated: "The
more important fundamental laws and facts of physical science have all
been discovered, and these are now so firmly established that the
possibility of their ever being supplanted in consequence of new
discoveries is exceedingly remote... Our future discoveries must be
looked for in the sixth place of decimals."
But in 1895, Roentgen discovered X rays. In 1896, Becquerel
discovered radioactivity. In 1897, Thomson discovered the electron. In
1905, Einstein formulated the special theory of relativity (and thus
explained Michelson's own 1887 observations regarding the speed of
light). In 1905, Einstein also presented the photon theory of light.
In 1911, Rutherford discovered the atomic nucleus. In 1915, Einstein
formulated the general theory of relativity. In 1924-30, de Broglie,
Heisenberg, Bohr, Pauli, and Dirac developed the foundations of
quantum mechanics. In 1929, Hubble announced evidence for the
expansion of the universe. In 1931, Michelson died.
Michelson had made a memorable mistake. People still point to his
statement and what followed to support the view that we shouldn't
(ever?) claim any firm understanding of natural law, or of the
limits to the possible. After all, if Michelson was so sure and yet so
wrong, shouldn't we fear repeating his mistake? The great revolution
in physics has led some people to conclude that science will hold
endless important surprises- even surprises important to engineers.
But are we likely to encounter such an important upheaval again?
Perhaps not. The content of quantum mechanics was a surprise, yet
before it appeared, physics was obviously and grossly incomplete.
Before quantum mechanics, you could have walked up to any scientist,
grinned maliciously, rapped on his desk and asked, "What holds this
thing together? Why is it brown and solid, while air is transparent
and gaseous?" Your victim might have said something vague*(178)
about atoms and their arrangements, but when you pressed for an
explanation, you would at best have gotten an answer like "Who
knows? Physics can't explain matter yet!" Hindsight is all too easy,
yet in a world made of matter, inhabited by material people using
material tools, this ignorance of the nature of matter was a gap in
human knowledge that Michelson should perhaps have noted. It was a gap
not in "the sixth place of decimals" but in the first.
It is also worth observing the extent to which Michelson was
right. The laws of which he spoke included Newton's laws of gravity
and motion, and Maxwell's laws of electromagnetism. And indeed,
under conditions common in engineering, these laws have been
modified only "in the sixth place of decimals." Einstein's laws of
gravity and motion match Newton's laws closely except under extreme
conditions of gravitation and speed; the quantum electrodynamic laws
of Feynman, Schwinger, and Tomonaga match Maxwell's laws closely
except under extreme conditions of size and energy.
Further revolutions no doubt lurk around the edges of these
theories. But those edges seem far from the world of living things and
the machines we build. The revolutions of relativity and quantum
mechanics changed our knowledge about matter and energy, but matter
and energy themselves remained unchanged- they are real and care
nothing for our theories. Physicists now use a single set of laws to
describe how atomic nuclei and electrons interact in atoms, molecules,
molecular machines, living things, planets, and stars. These laws
are not yet completely general; the quest for a unified theory of
all physics continues. But as physicist Stephen W. Hawking
states,*(179) "at the moment we have a number of partial laws which
govern the behavior of the universe under all but the most extreme
conditions." And by an engineer's standards, those conditions are
extraordinarily extreme.
Physicists regularly announce new particles observed in the debris
from extremely energetic particle collisions, but you cannot buy one
of these new particles in a box. And this is important to recognize,
because if a particle cannot be kept, then it cannot serve as a
component of a stable machine. Boxes and their contents are made of
electrons and nuclei. Nuclei, in turn, are made of protons and
neutrons. Hydrogen atoms have single protons as their nuclei; lead
atoms have eighty-two protons and over a hundred neutrons. Isolated
neutrons disintegrate in a few minutes. Few other stable particles are
known:*(180) photons- the particles of light- are useful and can be
trapped for a time; neutrinos are almost undetectable and cannot
even be trapped. These particles (save the photon) have matching
antiparticles. All other known particles disintegrate in a few
millionths of a second or less. Thus, the only known building blocks
for hardware are electrons and nuclei (or their antiparticles, for
special isolated applications); these building blocks ordinarily
combine to form atoms and molecules.
Yet despite the power of modern physics, our knowledge still has
obvious holes. The shaky state of elementary particle theory leaves
some limits uncertain. We may find new stable, "boxable" particles,
such as magnetic monopoles or free quarks; if so, they will
doubtless have uses. We may even find a new long-range field or form
of radiation, though this seems increasingly unlikely. Finally, some
new way of smashing particles together may improve our ability to
convert known particles into other known particles.
But in general, complex hardware will require complex, stable
patterns of particles. Outside the environment of a collapsed star,
this means patterns of atoms, which are well described by relativistic
quantum mechanics. The frontiers of physics have moved on. On a
theoretical level, physicists seek a unified description of the
interactions of all possible particles, even the most short-lived
particles. On an experimental level, they study the patterns of
subatomic debris created by high-energy collisions in particle
accelerators. So long as no new, stable, and useful particle comes out
of such a collision- or turns up as the residue of past cosmic
upheavals- atoms will remain the sole building blocks of stable
hardware. And engineering will remain a game that is played with
already known pieces according to already known rules. New particles
would add pieces, not eliminate rules.
-
THE LIMITS TO HARDWARE
-
Is molecular machinery really the end of the road where
miniaturization is concerned? The idea that molecular machinery
might be a step toward a smaller "nuclear machinery" seems natural
enough. One young man (a graduate student in economics at Columbia
University) heard of molecular technology and its ability to
manipulate atoms, and immediately concluded that molecular
technology could do almost anything, even turn falling nuclear bombs
into harmless lead bricks at a distance.
Molecular technology can do no such thing. Turning plutonium into
lead (whether at a distance or not) lies beyond molecular technology
for the same reason that turning lead into gold lay beyond an
alchemist's chemistry. Molecular forces have little effect on the
atomic nucleus. The nucleus holds over 99.9 percent of an atom's
mass and occupies about 1/1,000,000,000,000,000 of its volume.
Compared to the nucleus, the rest of an atom (an electron cloud) is
less than airy fluff. Trying to change a nucleus*(181) by poking at it
with a molecule is even more futile than trying to flatten a steel
ball bearing by waving a ball of cotton candy at it. Molecular
technology can sort and rearrange atoms, but it cannot reach into a
nucleus to change an atom's type.
Nanomachines may be no help in building nuclear-scale machines,
but could such machines even exist? Apparently not, at least under any
conditions we can create in a laboratory. Machines must have a
number of parts in close contact, but close-packed nuclei repel each
other with ferocity. When splitting nuclei blasted Hiroshima, most
of the energy was released by the violent electrostatic repulsion of
the freshly split halves. The well-known difficulty of nuclear
fusion stems from this same problem of nuclear repulsion.
In addition to splitting or fusing, nuclei can be made to emit or
absorb various types of radiation. In one technique, they are made
to gyrate in ways that yield useful information, letting doctors
make medical images based on nuclear magnetic resonance. But all these
phenomena rely only on the properties of well-separated
nuclei.*(182) Isolated nuclei are too simple to act as machines or
electronic circuits. Nuclei can be forced close together, but only
under the immense pressures found inside a collapsed star. Doing
engineering there would present substantial difficulties,*(183) even
if a collapsed star were handy.
This returns us to the basic question, What can we accomplish by
properly arranging atoms? Some limits already seem clear. The
strongest materials possible will have roughly ten times the
strength of today's strongest steel wire. (The strongest material
for making a cable appears to be carbyne, a form of carbon having
atoms arranged in straight chains.) It seems that the vibrations of
heat will, at ordinary pressures, tear apart the most refractory
solids at temperatures around four thousand degrees Celsius (roughly
fifteen hundred degrees cooler than the Sun's surface).
These brute properties of matter- strength and heat resistance-
cannot be greatly improved through complex, clever arrangements of
atoms. The best arrangements seem likely to be fairly simple and
regular. Other fairly simple goals include transmitting heat,
insulating against heat,*(184) transmitting electricity, insulating
against electricity, transmitting light, reflecting light, and
absorbing light.
With some goals, pursuit of perfection will lead to simple
designs; with others, it will lead to design problems beyond any
hope of solving. Designing the best possible switching component for a
computer may prove fairly easy; designing the best possible computer
will be vastly more complex. Indeed, what we consider to be "the
best possible" will depend on many factors, including the costs of
matter, energy and time- and on what we want to compute. In any
engineering project, what we call "better" depends on indefinitely
many factors, including ill-defined and changing human wants. What
is more, even where "better" is well defined, the cost of seeking
the final increment of improvement that separates the best from the
merely excellent may not be worth paying. We can ignore all such
issues of complexity and design cost, though, when considering whether
limits actually exist.
To define a limit, one must choose a direction, a scale of
quality. With that direction defining "better," there will
definitely be a best. The arrangement of atoms determines the
properties of hardware, and according to quantum mechanics, the number
of possible arrangements is finite- more than just astronomically
large, yet not infinite. It follows mathematically that, given a clear
goal, some one of these arrangements must be best, or tied for best.
As in chess, the limited number of pieces and spaces limits the
arrangements and hence the possibilities. In both chess and
engineering, though, the variety possible within those limits is
inexhaustible.
Just knowing the fundamental laws of matter isn't enough to tell
us exactly where all the limits lie. We still must face the
complexities of design. Our knowledge of some limits remains loose:
"We know only that the limit lies between here (a few paces away)
and there (that spot near the horizon)." Assemblers will open the
way to the limits, wherever they are, and automated engineering
systems will speed progress along the road. The absolute best will
often prove elusive, but the runners-up will often be nearly as
good.*(185)
As we approach genuine limits, our abilities will, in ever more
areas of technology, cease growing. Advances in these fields will stop
not merely for a decade or a century, but permanently.
Some may balk at the word "permanently," thinking "No improvements
in a thousand years? In a million years? This must be an
overstatement." Yet where we reach true physical limits, we will go no
further. The rules of the game are built into the structure of the
vacuum, into the structure of the universe. No rearranging of atoms,
no clashing of particles, no legislation or chanting or stomping
will move natural limits one whit. We may misjudge the limits today,
but wherever the real limits lie, there they will remain.
-
This look at natural law shows limits to the quality of things.
But we also face limits to quantity, set not only by natural law but
by the way that matter and energy are arranged in the universe as we
happen to find it. The authors of The Limits to Growth, like so many
others, attempted to describe these limits without first examining the
limits to technology. This gave misleading results.
-
ENTROPY: A LIMIT TO ENERGY USE
-
Recently, some authors have described the accumulation of waste heat
and disorder as ultimate limits to human activity. In The Lean
Years- Politics in the Age of Scarcity, Richard Barnet writes:*(186)
"It is ironical that the rediscovery of limits coincides with two of
the most audacious technological feats in human history. One is
genetic engineering, the sudden glimpse of a power to shape the very
stuff of life. The other is the colonization of space. These
breakthroughs encourage fantasies of power, but they do not break
the ecological straightjacket known as the Second Law of
Thermodynamics: Ever greater consumption of energy produces ever
greater quantities of heat, which never disappear, but must be counted
as a permanent energy cost. Since accumulation of heat can cause
ecological catastrophe, these costs limit man's adventure in space
as surely as on earth."
Jeremy Rifkin (with Ted Howard) has written*(187) an entire book
on thermodynamic limits and the future of humanity, titled Entropy:
A New World View.
Entropy is a standard scientific measure of waste heat and disorder.
Whenever activities consume useful energy, they produce entropy; the
entropy of the world therefore increases steadily and irreversibly.
Ultimately, the dissipation of useful energy will destroy the basis of
life. As Rifkin says, this idea may seem too depressing to consider,
but he argues that we must face the terrible facts about entropy,
humanity, and the Earth. But are these facts so terrible?
Barnet writes that accumulating heat is a permanent energy cost,
limiting human action. Rifkin states that "pollution is the sum
total of all of the available energy in the world that has been
transformed into unavailable energy." This unavailable energy is
chiefly low-temperature waste heat, the sort that makes television
sets get warm. But does heat really accumulate, as Barnet fears? If
so, then the Earth must be growing steadily hotter, minute by minute
and year by year. We should be roasting now, if our ancestors
weren't frozen solid. Somehow, though, continents manage to get cold
at night, and colder yet during the winter. During ice ages, the whole
Earth cools off.
Rifkin takes another tack. He states that "the fixed endowment of
terrestrial matter that makes up the earth's crust is constantly
dissipating. Mountains are wearing down and topsoil is being blown
away with each passing second." By "blown away" Rifkin doesn't mean
blown into space or blown out of existence; he just means that the
mountain's atoms have become jumbled together with others. Yet this
process, he argues, means our doom. The jumbling of atoms makes them
"unavailable matter," as a consequence of the "fourth law of
thermodynamics," propounded by economist Nicholas Georgescu-Roegen:
"In a closed system, the material entropy must ultimately reach a
maximum," or (equivalently) that "unavailable matter cannot be
recycled." Rifkin declares that the Earth is a closed system,
exchanging energy but not matter with its surroundings, and that
therefore "here on earth material entropy is continually increasing
and must ultimately reach a maximum," making Earth's life falter and
die.
A grim situation indeed- the Earth has been degenerating for
billions of years. Surely the end must be near!
But can this really be true? As life developed, it brought more
order to Earth, not less; the formation of ore deposits did the
same. The idea that Earth has degenerated seems peculiar at best
(but then, Rifkin thinks evolution is bunk). Besides, since matter and
energy are essentially the same, how can a valid law single out
something called "material entropy" in the first place?
Rifkin presents perfume spreading from a bottle into the air in a
room as an example of "dissipating matter," of material entropy
increasing- of matter becoming "unavailable." The spread of salt
into water in a bottle will serve equally well. Consider, then, a test
of the "fourth law of thermodynamics" in the Salt-Water Bottle
Experiment:
-
Imagine a bottle having a bottom with a partition, dividing it
into two basins. In one sits salt, in the other sits water. A cork
plugs the bottle's neck: this closes the system and makes the
so-called fourth law of thermodynamics apply. The bottle's contents
are in an organized state: their material entropy is not at a maximum-
yet.
Now, pick up the bottle and shake it. Slosh the water into the other
basin, swirl it around, dissolve the salt, increase the entropy- go
wild! In such a closed system, the "fourth law of thermodynamics" says
that this increase in the material entropy should be permanent. All of
Rifkin's alarums about the steady, inevitable increase of Earth's
entropy rest on this principle.
To see if there is any basis for Rifkin's new worldview, take the
bottle and tip it, draining the salty water into one basin. This
should make no difference, since the system remains closed. Now set
the bottle upright, placing the saltwater side in sunlight and the
empty side in shade. Light shines in and heat leaks out, but the
system remains as closed as the Earth itself. But watch- the
sunlight evaporates water, which condenses in the shade! Fresh water
slowly fills the empty basin, leaving the salt behind.
-
Rifkin himself states that "in science, only one uncompromising
exception is enough to invalidate a law." This thought experiment,
which mimics how natural salt deposits have formed on Earth,
invalidates the law on which he founds his whole book. So do plants.
Sunlight brings energy from space; heat radiated back into space
carries away entropy (of which there is only one kind). Therefore,
entropy can decline in a closed system and flowers can bloom on
Earth for age upon age.
Rifkin is right in saying that "it's possible to reverse the entropy
process in an isolated time and place, but only by using up energy
in the process and thus increasing the overall entropy of the
environment." But both Rifkin and Barnet make the same mistake: when
they write of the environment, they imply the Earth- but the law
applies to the environment as a whole, and that whole is the universe.
In effect, Rifkin and Barnet ignore both the light of the Sun and
the cold black of the night sky.
According to Rifkin, his ideas destroy the notion of history as
progress, transcending the modern worldview. He calls for sacrifice,
stating that "no Third World nation should harbor hopes that it can
ever reach the material abundance that has existed in America." He
fears panic and bloodshed. Rifkin finishes by informing us that "the
Entropy Law answers the central question that every culture throughout
history has grappled with: How should human beings behave in the
world?" His answer? "The ultimate moral imperative, then,*(188) is
to waste as little energy as possible."
This would seem to mean that we must save as much energy as
possible, seeking to eliminate waste. But what is the greatest
nearby energy waster? Why, the Sun, of course- it wastes energy
trillions of times faster than we humans do. If taken seriously, it
seems that Rifkin's ultimate moral imperative therefore urges: "Put
out the Sun!"
This silly consequence should have tipped Rifkin off. He and many
others hold views that smack of a pre-Copernican arrogance: they
presume that the Earth is the whole world and that what people do is
automatically of cosmic importance.
There is a genuine entropy law, of course: the second law of
thermodynamics. Unlike the bogus "fourth law," it is described in
textbooks and used by engineers. It will indeed limit what we do.
Human activity will generate heat, and Earth's limited ability to
radiate heat will set a firm limit to the amount of Earth-based
industrial activity. Likewise, we will need winglike panels to radiate
waste heat from our starships. Finally, the entropy law will- at the
far end of an immensity of time- bring the downfall of the universe as
we know it, limiting the lifespan of life itself.
-
Why flog the carcass of Rifkin's Entropy? Simply because today's
information systems often present even stillborn ideas as if they were
alive. By encouraging false hopes, false fears, and misguided
action, these ideas can waste the efforts of people actively concerned
about long-range world problems.
Among those whose praise appears on the back cover of Rifkin's
book ("an inspiring work," "brilliant work," "earth-shaking,"
"should be taken to heart") are a Princeton professor, a talk-show
host, and two United States senators. A seminar at MIT ("The Finite
Earth- World Views for a Sustainable Future") featured Rifkin's book.
All the seminar's sponsors were from nontechnical departments.
Most senators in our technological society lack training in
technology, as do most professors and talk-show hosts.
Georgescu-Roegen himself, inventor of the "fourth law of
thermodynamics," has extensive credentials- as a social scientist.
The entropy threat is an example of blatant nonsense, yet its
inventors and promoters aren't laughed off the public stage. Imagine a
thousand, a million similar distortions- some subtle, some brazen, but
all warping the public's understanding of the world. Now imagine a
group of democratic nations suffering from an infestation of such
memes while attempting to cope with an era of accelerating
technological revolution. We have a real problem. To make our survival
more likely, we will need better ways to weed our memes, to make
room for sound understanding to grow. In Chapters 13 and 14 I will
report on two proposals for how we might do this.
-
THE LIMITS TO RESOURCES
-
Natural law limits the quality of technology, but within these
limits we will use replicating assemblers to produce superior
spacecraft. With them, we will open space wide and deep.
Today Earth has begun to seem small, arousing concerns that we may
deplete its resources. Yet the energy we use totals less than 1/10,000
of the solar energy striking Earth; we worry not about the supply of
energy as such, but about the supply of convenient gas and oil. Our
mines barely scratch the surface of the globe; we worry not about
the sheer quantity of resources, but about their convenience and cost.
When we develop pollution-free nanomachines to gather solar energy and
resources, Earth will be able to support a civilization far larger and
wealthier than any yet seen, yet suffer less harm than we inflict
today. The potential of Earth makes the resources we now use seem
insignificant by comparison.
Yet Earth is but a speck. The asteroidal debris left over from the
formation of the planets will provide materials enough to build a
thousand times Earth's land area. The Sun floods the solar system with
a billion times the power that reaches Earth. The resources of the
solar system are truly vast, making the resources of Earth seem
insignificant by comparison.
Yet the solar system is but a speck. The stars that crowd the
night sky are suns, and the human eye can see only the closest. Our
galaxy holds a hundred billion suns, and many no doubt pour their
light on dead planets and asteroids awaiting the touch of life. The
resources of our galaxy make even our solar system seem
insignificant by comparison.
Yet our galaxy is but a speck. Light older than our species shows
galaxies beyond ours. The visible universe holds a hundred billion
galaxies, each a swarm of billions of suns. The resources of the
visible universe make even our galaxy seem insignificant by
comparison.
With this we reach the limits of knowledge, if not of resources. The
solar system seems answer enough to Earth's limits- and if the rest of
the universe remains unclaimed by others, then our prospects for
expansion boggle the mind several times over. Does this mean that
replicating assemblers and cheap spaceflight will end our resource
worries?
In a sense, opening space will burst our limits to growth, since
we know of no end to the universe. Nevertheless, Malthus was
essentially right.
-
MALTHUS
-
In his 1798 Essay on the Principle of Population, Thomas Robert
Malthus, an English clergyman, presented the ancestor of all modern
limits-to-growth arguments. He noted that freely growing populations
tend to double periodically, thus expanding exponentially. This
makes sense: since all organisms are descended from successful
replicators, they tend to replicate when given a chance. For the
sake of argument, Malthus assumed that resources- the food supply-
could increase by a fixed amount per year (a process called linear
growth, since it plots as a line on a graph). Since mathematics
shows that any fixed rate of exponential growth will eventually
outstrip any fixed rate of linear growth, Malthus argued that
population growth, if unchecked, would eventually outrun food
production.
Authors have repeated variations on this idea ever since, in books
like The Population Bomb and Famine- 1975!, yet food production has
kept pace with population. Outside Africa, it has even pulled ahead.
Was Malthus wrong?
Not fundamentally: he was wrong chiefly about timing and details.
Growth on Earth does face limits, since Earth has limited room,
whether for farming or anything else. Malthus failed to predict when
limits would pinch us chiefly because he failed to anticipate
breakthroughs in farm equipment, crop genetics, and fertilizers.
Some people now note that exponential growth will overrun*(189)
the fixed stock of Earth's resources, a simpler argument than the
one Malthus made. Though space technology will break this limit, it
will not break all limits. Even if the universe were infinitely large,
we still could not travel infinitely fast. The laws of nature will
limit the rate of growth: Earth's life will spread no faster than
light.
Steady expansion will open new resources at a rate that will
increase as the frontier spreads deeper and wider into space. This
will result not in linear growth, but in cubic growth. Yet Malthus was
essentially right: exponential growth will outrun cubic growth as
easily as it would linear. Calculations show that unchecked population
growth, with or without long life, would overrun available resources
in about one or two thousand years at most. Unlimited exponential
growth remains a fantasy, even in space.
-
WILL SOMEONE STOP US?
-
Do other civilizations already own the resources of the universe? If
so, then they would represent a limit to growth. The facts about
evolution and technological limits shed useful light on this question.
Since many Sunlike stellar systems are many hundreds of millions
of years older than our solar system, some civilizations (if any
substantial number exist) should be many hundreds of millions of years
ahead of ours. We would expect at least some of these civilizations to
do what all known life has done: spread as far as it can. Earth is
green not just in the oceans where life began, but on shores, hills,
and mountains. Green plants have now spread to stations in orbit; if
we prosper, Earth's plants will spread to the stars. Organisms
spread as far as they can, then a bit farther. Some fail and die,
but the successful survive and spread farther yet. Settlers bound
for America sailed and sank, and landed and starved, but some survived
to found new nations. Organisms everywhere will feel the pressures
that Malthus described, because they will have evolved to survive
and spread; genes and memes both push in the same direction. If
extraterrestrial civilizations exist, and if even a small fraction
were to behave as all life on Earth does, then they should by now have
spread across space.
Like us, they would tend to evolve technologies that approach the
limits set by natural law. They would learn how to travel near the
speed of light, and competition or sheer curiosity would drive some to
do so. Indeed, only highly organized, highly stable societies could
restrain competitive pressures well enough to avoid exploding
outward at near the speed of light.*(190) By now, after hundreds of
millions of years, even widely scattered civilizations would have
spread far enough to meet each other, dividing all of space among
them.
If these civilizations are indeed everywhere, then they have shown
great restraint and hidden themselves well. They would have controlled
the resources of whole galaxies for many millions of years, and
faced limits to growth on a cosmic scale. An advanced civilization
pushing its ecological limits would, almost by definition, not waste
both matter and energy. Yet we see such waste in all directions, as
far as we can see spiral galaxies: their spiral arms hold dust
clouds made of wasted matter, backlit by wasted starlight.
If such advanced civilizations existed, then our solar system
would lie in the realm of one of them. If so, then it would now be
their move- we could do nothing to threaten them, and they could study
us as they pleased, with or without our cooperation. Sensible people
would listen if they firmly stated a demand. But if they exist, they
must be hiding themselves- and keeping any local laws secret.
The idea that humanity is alone in the visible universe is
consistent with what we see in the sky and with what we know about the
origin of life. No bashful aliens are needed to explain the facts.
Some say that since there are so many stars, there must surely be
other civilizations among them. But there are fewer stars in the
visible universe than there are molecules in a glass of water. Just as
a glass of water need not contain every possible chemical*(191)
(even downstream from a chemical plant), so other stars need not
harbor civilizations.
We know that competing replicators tend to expand toward their
ecological limits, and that resources are nonetheless wasted
throughout the universe. We have received no envoy from the stars, and
we apparently lack even a tolerably humane zookeeper. There may well
be no one there. If they do not exist, then we need not consider
them in our plans. If they do exist, then they will overrule our plans
according to their own inscrutable wishes, and there seems no way to
prepare for the possibility. Thus for now, and perhaps forever, we can
make plans for our future without concern for limits imposed by
other civilizations.
-
GROWTH WITHIN LIMITS
-
Whether anyone else is out there or not, we are on our way. Space
waits for us, barren rock and sunlight like the barren rock and
sunlight of Earth's continents a billion years ago, before life
crept forth from the sea. Our engineers are evolving memes that will
help us create fine spaceships and settlements: we will settle the
land of the solar system in comfort. Beyond the rich inner solar
system lies the cometary cloud- a vast growth medium that thins away
into the reaches of interstellar space, then thickens once more around
other star systems, with fresh suns and sterile rock awaiting the
touch of life.
Although endless exponential growth remains a fantasy, the spread of
life and civilization faces no fixed bound. Expansion will proceed, if
we survive, because we are part of a living system and life tends to
spread. Pioneers will move outward into worlds without end. Others
will remain behind, building settled cultures throughout the oases
of space. In any settlement, the time will come when the frontier lies
far away, then farther. For the bulk of the future, most people and
their descendants will live with limits to growth.
We may like or dislike limits to growth, but their reality is
independent of our wishes. Limits exist wherever goals are clearly
defined.
But on frontiers where standards keep changing, this idea of
limits becomes irrelevant. In art or mathematics the value of work
depends on complex standards, subject to dispute and change. One of
those standards is novelty, and this can never be exhausted. Where
goals change and complexity rules, limits need not bind us. To the
creation of symphony and song, paintings and worlds, software,
theorems, films, and delights yet unimagined, there seems no end.
New technologies will nurture new arts, and new arts will bring new
standards.
The world of brute matter offers room for great but limited
growth. The world of mind and pattern, though, holds room for
endless evolution and change. The possible seems room enough.
-
VIEWS OF LIMITS.
-
The idea of great advances within firm limits isn't evolved to
feel pleasing, but to be accurate. Limits outline possibilities, and
some may be ugly or terrifying. We need to prepare for the
breakthroughs ahead, yet many futurists studiously pretend that no
breakthroughs will occur.
This school of thought is associated with The Limits to
Growth,*(192) published as a report to the Club of Rome. Professor
Mihajlo D. Mesarovic later coauthored Mankind at the Turning
Point,*(193) published as the second report to the Club of Rome.
Professor Mesarovic develops computer models like the one used in
The Limits to Growth- each is a set of numbers and equations that
purports to describe future changes in the world's population,
economy, and environment. In the spring of 1981, he visited MIT to
address "The Finite Earth: Worldviews for a Sustainable Future," the
same seminar that featured Jeremy Rifkin's Entropy. He described a
model intended to give a rough description of the next century. When
asked whether he or any of his colleagues had allowed for even one
future breakthrough comparable to, say, the petroleum industry,
aircraft, automobiles, electric power, or computers- perhaps
self-replicating robotic systems or cheap space transportation?- he
answered directly: "No."
Such models of the future are obviously bankrupt. Yet some people
seem willing- even eager- to believe that breakthroughs will
suddenly cease, that a global technology race that has been gaining
momentum for centuries will screech to a halt in the immediate future.
The habit of neglecting or denying the possibility of
technological advance is a common problem. Some people believe in
snugly fitting limits because they have heard respected people spin
plausible-sounding arguments for them. Yet it seems that some people
must be responding more to wish than to fact, after this century of
accelerating advance. Snug limits would simplify our future, making it
easier to understand and more comfortable to think about. A belief
in snug limits also relieves a person of certain concerns and
responsibilities. After all, if natural forces will halt the
technology race in a convenient and automatic fashion, then we needn't
try to understand and control it.
Best of all, this escape doesn't feel like escapism. To
contemplate visions of global decline must give the feeling of
facing harsh facts without flinching. Yet such a future would be
nothing really new: it would force us toward the familiar miseries
of the European past or the Third World present. Genuine courage
requires facing reality, facing accelerating change in a world that
has no automatic brakes. This poses intellectual, moral, and political
challenges of greater substance.
Warnings of bogus limits do double harm. First, they discredit the
very idea of limits, blunting an intellectual tool that we will need
to understand our future. But worse, such warnings distract
attention from our real problems. In the Western world there is a
lively political tradition that fosters suspicion of technology. To
the extent that it first disciplines its suspicions by testing them
against reality and then chooses workable strategies for guiding
change, this tradition can contribute mightily to the survival of life
and civilization. But people concerned about technology and the future
are a limited resource. The world cannot afford to have their
efforts squandered in futile campaigns to sweep back the global tide
of technology with the narrow broom of Western protest movements.
The coming problems demand more subtle strategies.
No one can yet say for certain what problems will prove to be most
important, or what strategies will prove best for solving them. Yet we
can already see novel problems of great importance, and we can discern
strategies with varying degrees of promise. In short, we can see
enough about the future to identify goals worth pursuing.
PART THREE
Dangers and Hopes
-
11
Engines of Destruction
-
Nor do I doubt if the most formidable armies ever heere upon earth
is a sort of soldiers who for their smallness are not visible.
-Sir WILLIAM PERRY, on microbes, 1640
-
REPLICATING assemblers and thinking machines pose basic threats to
people and to life on Earth. Today's organisms have abilities far from
the limits of the possible, and our machines are evolving faster
than we are. Within a few decades they seem likely to surpass us.
Unless we learn to live with them in safety, our future will likely be
both exciting and short. We cannot hope to foresee all the problems
ahead, yet by paying attention to the big, basic issues, we can
perhaps foresee the greatest challenges and get some idea of how to
deal with them.
Entire books will no doubt be written on the coming social
upheavals: What will happen to the global order when assemblers and
automated engineering eliminate the need for most international trade?
How will society change when individuals can live indefinitely? What
will we do when replicating assemblers can make almost anything
without human labor? What will we do when AI systems can think
faster than humans? (And before they jump to the conclusion that
people will despair of doing or creating anything, the authors may
consider how runners regard cars, or how painters regard cameras.)
In fact, authors have already foreseen and discussed several of
these issues. Each is a matter of uncommon importance, but more
fundamental than any of them is the survival of life and liberty.
After all, if life or liberty is obliterated, then our ideas about
social problems will no longer matter.
-
THE THREAT FROM THE MACHINES
-
In Chapter 4, I described some of what replicating assemblers will
do for us if we handle them properly. Powered by fuels or sunlight,
they will be able to make almost anything (including more of
themselves) from common materials.
Living organisms are also powered by fuels or sunlight, and also
make more of themselves from ordinary materials. But unlike
assembler-based systems, they cannot make "almost anything."
Genetic evolution has limited life to a system based on DNA, RNA,
and ribosomes, but memetic evolution will bring life-like machines
based on nanocomputers and assemblers. I have already described how
assembler-built molecular machines will differ from the ribosome-built
machinery of life. Assemblers will be able to build all that ribosomes
can, and more; assembler-based replicators will therefore be able to
do all that life can, and more. From an evolutionary point of view,
this poses an obvious threat to otters, people, cacti, and ferns- to
the rich fabric of the biosphere and all that we prize.
The early transistorized computers soon beat the most advanced
vacuum-tube computers because they were based on superior devices. For
the same reason, early assembler-based replicators could beat the most
advanced modern organisms. "Plants" with "leaves" no more efficient
than today's solar cells could out-compete real plants, crowding the
biosphere with an inedible foliage. Tough, omnivorous "bacteria" could
out-compete real bacteria: they could spread like blowing pollen,
replicate swiftly, and reduce the biosphere to dust in a matter of
days. Dangerous replicators could easily be too tough, small, and
rapidly spreading to stop- at least if we made no preparation. We have
trouble enough controlling viruses and fruit flies.*(194)
Among the cognoscenti of nanotechnology, this threat has become
known as the "gray goo problem." Though masses of uncontrolled
replicators need not be gray or gooey, the term "gray goo"
emphasizes that replicators able to obliterate life might be less
inspiring than a single species of crabgrass. They might be "superior"
in an evolutionary sense, but this need not make them valuable. We
have evolved to love a world rich in living things, ideas, and
diversity, so there is no reason to value gray goo merely because it
could spread. Indeed, if we prevent it we will thereby prove our
evolutionary superiority.
The gray goo threat makes one thing perfectly clear: we cannot
afford certain kinds of accidents with replicating assemblers.
-
In Chapter 5, I described some of what advanced AI systems will do
for us, if we handle them properly. Ultimately, they will embody the
patterns of thought and make them flow at a pace no mammal's brain can
match. AI systems that work together as people do will be able to
out-think not just individuals, but whole societies. Again, the
evolution of genes has left life stuck. Again, the evolution of
memes by human beings- and eventually by machines- will advance our
hardware far beyond the limits of life. And again, from an
evolutionary point of view this poses an obvious threat.
Knowledge can bring power, and power can bring knowledge.
Depending on their natures and their goals, advanced AI systems
might accumulate enough knowledge and power to displace us, if we
don't prepare properly. And as with replicators, mere evolutionary
"superiority" need not make the victors better than the vanquished
by any standard but brute competitive ability.
This threat makes one thing perfectly clear: we need to find ways to
live with thinking machines, to make them law-abiding citizens.
-
ENGINES OF POWER
-
Certain kinds of replicators and AI systems may confront us with
forms of hardware capable of swift, effective, independent action. But
the novelty of this threat- coming from the machines themselves-
must not blind us to a more traditional danger. Replicators and AI
systems can also serve as great engines of power, if wielded freely by
sovereign states.
Throughout history, states have developed technologies to extend
their military power, and states will no doubt play a dominant role in
developing replicators and AI systems. States could use replicating
assemblers to build arsenals of advanced weapons, swiftly, easily, and
in vast quantity. States could use special replicators directly to
wage a sort of germ warfare- one made vastly more practical by
programmable, computer-controlled "germs." Depending on their
skills, AI systems could serve as weapon designers, strategists, or
fighters.*(195) Military funds already support research in both
molecular technology and artificial intelligence.
States could use assemblers or advanced AI systems to achieve
sudden, destabilizing breakthroughs. I earlier discussed reasons for
expecting that the advent of replicating assemblers will bring
relatively sudden changes: Able to replicate swiftly, they could
become abundant in a matter of days. Able to make almost anything,
they could be programmed to duplicate existing weapons, but made
from superior materials. Able to work with standard, well-understood
components (atoms) they could suddenly build things designed in
anticipation of the assembler breakthrough. These results of
design-ahead could include programmable germs and other nasty
novelties. For all these reasons, a state that makes the assembler
breakthrough could rapidly create a decisive military force- if not
literally overnight, then at least with unprecedented speed.
States could use advanced AI systems to similar ends. Automated
engineering systems will facilitate design-ahead and speed assembler
development. AI systems able to build better AI systems will allow
an explosion of capability with effects hard to anticipate. Both AI
systems and replicating assemblers will enable states to expand
their military capabilities by orders of magnitude in a brief time.
Replicators can be more potent than nuclear weapons: to devastate
Earth with bombs would require masses of exotic hardware and rare
isotopes, but to destroy all life with replicators would require
only a single speck made of ordinary elements. Replicators give
nuclear war some company as a potential cause of extinction, giving
a broader context to extinction as a moral concern.
-
Despite their potential as engines of destruction, nanotechnology
and AI systems will lend themselves to more subtle uses than do
nuclear weapons. A bomb can only blast things, but nanomachines and AI
systems could be used to infiltrate, seize, change, and govern a
territory or a world. Even the most ruthless police have no use for
nuclear weapons, but they do have use for bugs, drugs, assassins,
and other flexible engines of power. With advanced technology,
states will be able to consolidate their power over people.
Like genes, memes, organisms, and hardware, states have evolved.
Their institutions have spread (with variations) through growth,
fission, imitation, and conquest. States at war fight like beasts, but
using citizens as their bones, brains, and muscle. The coming
breakthroughs will confront states with new pressures and
opportunities, encouraging sharp changes in how states behave. This
naturally gives cause for concern. States have, historically, excelled
at slaughter and oppression.
In a sense, a state is simply the sum of the people making up its
organizational apparatus: their actions add up to make its actions.
But the same might be said of a dog and its cells, though a dog is
clearly more than just a clump of cells. Both dogs and states are
evolved systems, with structures that affect how their parts behave.
For thousands of years, dogs have evolved largely to please people,
because they have survived and reproduced at human whim. For thousands
of years, states have evolved under other selective pressures.
Individuals have far more power over their dogs than they do over
"their" states. Though states, too, can benefit from pleasing
people, their very existence has depended on their capability for
using people, whether as leaders, police, or soldiers.
It may seem paradoxical to say that people have limited power over
states: After all, aren't people behind a state's every action? But in
democracies, heads of state bemoan their lack of power,
representatives bow to interest groups, bureaucrats are bound by
rules, and voters, allegedly in charge, curse the whole mess. The
state acts and people affect it, yet no one can claim to control it.
In totalitarian states, the apparatus of power has a tradition,
structure, and inner logic that leaves no one free, neither the rulers
nor the ruled. Even kings had to act in ways limited by the traditions
of monarchy and the practicalities of power, if they were to remain
kings. States are not human, though they are made of humans.
Despite this, history shows that change is possible, even change for
the better. But changes always move from one semiautonomous, inhuman
system to another- equally inhuman but perhaps more humane. In our
hope for improvements, we must not confuse states that wear a human
face with states that have humane institutions.
Describing states as quasi-organisms captures only one aspect of a
complex reality, yet it suggests how they may evolve in response to
the coming breakthroughs. The growth of government power, most
spectacular in totalitarian countries, suggests one direction.
States could become more like organisms by dominating their parts
more completely. Using replicating assemblers, states could fill the
human environment with miniature surveillance devices. Using an
abundance of speech-understanding AI systems, they could listen to
everyone without employing half the population as listeners. Using
nanotechnology like that proposed for cell repair machines, they could
cheaply tranquilize, lobotomize, or otherwise modify entire
populations. This would simply extend an all too familiar pattern. The
world already holds governments that spy, torture, and drug;
advanced technology will merely extend the possibilities.
But with advanced technology, states need not control people- they
could instead simply discard people. Most people in most states, after
all, function either as workers, larval workers, or worker-rearers,
and most of these workers make, move, or grow things. A state with
replicating assemblers would not need such work. What is more,
advanced AI systems could replace engineers, scientists,
administrators, and even leaders. The combination of nanotechnology
and advanced AI will make possible intelligent, effective robots; with
such robots, a state could prosper while discarding anyone, or even
(in principle) everyone.
The implications of this possibility depend on whether the state
exists to serve the people, or the people exist to serve the state.
In the first case, we have a state shaped by human beings to serve
general human purposes; democracies tend to be at least rough
approximations to this ideal. If a democratically controlled
government loses its need for people, this will basically mean that it
no longer needs to use people as bureaucrats or taxpayers. This will
open new possibilities, some of which may prove desirable.
In the second case, we have a state evolved to exploit human beings,
perhaps along totalitarian lines. States have needed people as workers
because human labor has been the necessary foundation of power. What
is more, genocide has been expensive and troublesome to organize and
execute. Yet, in this century totalitarian states have slaughtered
their citizens by the millions. Advanced technology will make
workers unnecessary and genocide easy. History suggests that
totalitarian states may then eliminate people wholesale. There is some
consolation in this. It seems likely that a state willing and able
to enslave us biologically would instead simply kill us.
The threat of advanced technology in the hands of governments
makes one thing perfectly clear: we cannot afford to have an
oppressive state take the lead in the coming breakthroughs.
-
The basic problems I have outlined are obvious: in the future, as in
the past, new technologies will lend themselves to accidents and
abuse. Since replicators and thinking machines will bring great new
powers, the potential for accidents and abuse will likewise be
great. These possibilities pose genuine threats to our lives.
Most people would like a chance to live and be free to choose how to
live. This goal may not sound too utopian, at least in some parts of
the world. It doesn't mean forcing everyone's life to fit some grand
scheme; it chiefly means avoiding enslavement and death. Yet, like the
achievement of a utopian dream, it will bring a future of wonders.
Given these life-and-death problems and this general goal, we can
consider what measures might help us succeed. Our strategy must
involve people, principles, and institutions, but it must also rest on
tactics which inevitably will involve technology.
-
TRUSTWORTHY SYSTEMS
-
To use such powerful technologies in safety, we must make hardware
we can trust. To have trust, we must be able to judge technical
facts accurately, an ability that will in turn depend partly on the
quality of our institutions for judgment. More fundamentally,
though, it will depend on whether trustworthy hardware is physically
possible. This is a matter of the reliability of components and of
systems.
We can often make reliable components, even without assemblers to
help. "Reliable" doesn't mean "indestructible"- anything will fail
if placed close enough to a nuclear blast. It doesn't even mean
"tough"- a television set may be reliable, yet not survive being
bounced off a concrete floor. Rather, we call something reliable
when we can count on it to work as designed.
A reliable component need not be a perfect embodiment of a perfect
design: it need only be a good enough embodiment of a cautious
enough design. A bridge engineer may be uncertain about the strength
of winds, the weight of traffic, and the strength of steel, but by
assuming high winds, heavy traffic, and weak steel, the engineer can
design a bridge that will stand.
Unexpected failures in components commonly stem from material flaws.
But assemblers will build components that have a negligible number
of their atoms out of place- none, if need be.*(196) This will make
them perfectly uniform and in a limited sense perfectly reliable.
Radiation will still cause damage, though, because a cosmic ray can
unexpectedly knock atoms loose from anything.*(197) In a small
enough component (even in a modern computer memory device), a single
particle of radiation can cause a failure.
But systems can work even when their parts fail; the key is
redundancy. Imagine a bridge suspended from cables that fail randomly,
each breaking about once a year at an unpredictable time. If the
bridge falls when a cable breaks, it will be too dangerous to use.
Imagine, though, that a broken cable takes a day to fix (because
skilled repair crews with spare cables are on call), and that,
though it takes five cables to support the bridge, there are
actually six. Now if one cable breaks, the bridge will still stand. By
clearing traffic and then replacing the failed cable, the bridge
operators can restore safety. To destroy this bridge, a second cable
must break in the same day as the first. Supported by six cables, each
having a one-in-365 daily chance of breaking, the bridge will likely
last about ten years.
While an improvement, this remains terrible. Yet a bridge with ten
cables (five needed, five extra) will fall only if six cables break on
the same day: the suspension system is likely to last over ten million
years. With fifteen cables, the expected lifetime is over ten thousand
times the age of the Earth. Redundancy can bring an exponential
explosion of safety.
Redundancy works best when the redundant components are truly
independent. If we don't trust the design process, then we must use
components designed independently; if a bomb, bullet, or cosmic ray
may damage several neighboring parts, then we must spread redundant
parts more widely. Engineers who want to supply reliable
transportation between two islands shouldn't just add more cables to a
bridge. They should build two well-separated bridges using different
designs, then add a tunnel, a ferry, and a pair of inland airports.
Computer engineers also use redundancy. Stratus Computer Inc., for
example,*(198) makes a machine that uses four central processing units
(in two pairs) to do the work of one, but to do it vastly more
reliably. Each pair is continually checked for internal consistency,
and a failed pair can be replaced while its twin carries on.
An even more powerful form of redundancy is design
diversity.*(199) In computer hardware, this means using several
computers with different designs, all working in parallel. Now
redundancy can correct not just for failures in a piece of hardware,
but for errors in its design.
Much has been made of the problem of writing large, error-free
programs; many people consider such programs impossible to develop and
debug. But researchers at the UCLA Computer Science Department have
shown that design diversity can also be used in software: several
programmers can tackle the same problem independently, then all
their programs can be run in parallel and made to vote on the
answer. This multiplies the cost of writing and running the program,
but it makes the resulting software system resistant to the bugs
that appear in some of its parts.
We can use redundancy to control replicators. Just as repair
machines that compare multiple DNA strands*(200) will be able to
correct mutations in a cell's genes, so replicators that compare
multiple copies of their instructions (or that use other effective
error-correcting systems)*(201) will be able to resist mutation in
these "genes." Redundancy can again bring an exponential explosion
of safety.
We can build systems that are extremely reliable, but this will
entail costs. Redundancy makes systems heavier, bulkier, more
expensive, and less efficient. Nanotechnology, though, will make
most things far lighter, smaller, cheaper, and more efficient to begin
with. This will make redundancy and reliability more practical.
Today, we are seldom willing to pay for the safest possible systems;
we tolerate failures more-or-less willingly and seldom consider the
real limits of reliability. This biases judgments of what can be
achieved. A psychological factor also distorts our sense of how
reliable things can be made: failures stick in our minds, but everyday
successes draw little attention. The media amplify this tendency by
reporting the most dramatic failures from around the world, while
ignoring the endless and boring successes. Worse yet, the components
of redundant systems may fail in visible ways, stirring alarums:
imagine how the media would report a snapped bridge cable, even if the
bridge were the super-safe fifteen-cable model described above. And
since each added redundant component adds to the chance of a component
failure, a system's reliability can seem worse even as it approaches
perfection.
Appearances aside, redundant systems made of abundant, flawless
components can often be made almost perfectly reliable. Redundant
systems spread over wide enough spaces will survive even bullets and
bombs.
But what about design errors? Having a dozen redundant parts will do
no good if they share a fatal error in design. Design diversity is one
answer; good testing is another. We can reliably evolve good designs
without being reliably good designers: we need only be good at
testing, good at tinkering, and good at being patient. Nature has
evolved working molecular machinery through entirely mindless
tinkering and testing. Having minds, we can do as well or better.
We will find it easy to design reliable hardware if we can develop
reliable automated engineering systems. But this raises the wider
issue of developing trustworthy artificial intelligence systems. We
will have little trouble making AI systems with reliable hardware, but
what about their software?
Like present AI systems and human minds, advanced AI systems will be
synergistic combinations of many simpler parts. Each part will be more
specialized and less intelligent than the system as a whole. Some
parts will look for patterns in pictures, sounds, and other data and
suggest what they might mean. Other parts will compare and judge the
suggestions of these parts. Just as the pattern recognizers in the
human visual system suffer from errors and optical illusions, so
will the pattern recognizers in AI systems. (Indeed, some advanced
machine vision systems already suffer from familiar optical
illusions.) And just as other parts of the human mind can often
identify and compensate for illusions, so will other parts of AI
systems.
As in human minds, intelligence will involve mental parts*(202) that
make shaky guesses and other parts that discard most of the bad
guesses before they draw much attention or affect important decisions.
Mental parts that reject action ideas on ethical grounds correspond to
what we call a conscience. AI systems with many parts will have room
for redundancy and design diversity, making reliability possible.
A genuine, flexible AI system must evolve ideas. To do this, it must
find or form hypotheses, generate variations, test them, and then
modify or discard those found inadequate. Eliminating any of these
abilities would make it stupid, stubborn, or insane ("Durn machine
can't think and won't learn from its mistakes- junk it!"). To avoid
becoming trapped by initial misconceptions, it will have to consider
conflicting views, seeing how well each explains the data, and
seeing whether one view can explain another.
Scientific communities go through a similar process. And in a
paper called "The Scientific Community Metaphor,"*(203) William A.
Kornfeld and Carl Hewitt of the MIT Artificial Intelligence Laboratory
suggest that AI researchers model their programs still more closely on
the evolved structure of the scientific community. They point to the
pluralism of science, to its diversity of competing proposers,
supporters, and critics. Without proposers, ideas cannot appear;
without supporters, they cannot grow; and without critics to weed
them, bad ideas can crowd out the good. This holds true in science, in
technology, in AI systems, and among the parts of our own minds.
Having a world full of diverse and redundant proposers,
supporters, and critics is what makes the advance of science and
technology reliable. Having more proposers makes good proposals more
common; having more critics makes bad proposals more vulnerable.
Better, more numerous ideas are the result. A similar form of
redundancy can help AI systems to develop sound ideas.
People sometimes guide their actions by standards of truth and
ethics, and we should be able to evolve AI systems that do likewise,
but more reliably. Able to think a million times faster than us,
they will have more time for second thoughts. It seems that AI systems
can be made trustworthy,*(204) at least by human standards.
I have often compared AI systems to individual human minds, but
the resemblance need not be close. A system that can mimic a person
may need to be personlike, but an automated engineering system
probably doesn't. One proposal*(205) (called an Agora system, after
the Greek term for a meeting and market place) would consist of many
independent pieces of software that interact by offering one another
services in exchange for money. Most pieces would be simple-minded
specialists, some able to suggest a design change, and others able
to analyze one. Much as Earth's ecology has evolved extraordinary
organisms, so this computer economy could evolve extraordinary
designs- and perhaps in a comparably mindless fashion. What is more,
since the system would be spread over many machines and have parts
written by many people, it could be diverse, robust, and hard for
any group to seize and abuse.
Eventually, one way or another, automated engineering systems will
be able to design things more reliably than any group of human
engineers*(206) can today. Our challenge will be to design them
correctly. We will need human institutions that reliably develop
reliable systems.
Human institutions are evolved artificial systems, and they can
often solve problems that their individual members cannot. This
makes them a sort of "artificial intelligence system." Corporations,
armies, and research laboratories all are examples, as are the
looser structures of the market and the scientific community. Even
governments may be seen as artificial intelligence systems- gross,
sluggish, and befuddled, yet superhuman in their sheer capability. And
what are constitutional checks and balances but an attempt to increase
a government's reliability through institutional diversity and
redundancy? When we build intelligent machines, we will use them to
check and balance one another.
By applying the same principles, we may be able to develop reliable,
technically oriented institutions having strong checks and balances,
then use these to guide the development of the systems we will need to
handle the coming breakthroughs.
-
TACTICS FOR THE ASSEMBLER BREAKTHROUGH
-
Some force in the world (whether trustworthy or not) will take the
lead in developing assemblers; call it the "leading force." Because of
the strategic importance of assemblers, the leading force will
presumably be some organization or institution that is effectively
controlled by some government or group of governments. To simplify
matters, pretend for the moment that we (the good guys, attempting
to be wise) can make policy for the leading force. For citizens of
democratic states, this seems a good attitude to take.
What should we do to improve our chances of reaching a future
worth living in? What can we do?
We can begin with what must not happen: we must not let a single
replicating assembler of the wrong kind be loosed on an unprepared
world. Effective preparations seem possible (as I will describe),
but it seems that they must be based on assembler-built systems that
can be built only after dangerous replicators have already become
possible. Design-ahead can help the leading force prepare, yet even
vigorous, foresighted action seems inadequate to prevent a time of
danger. The reason is straightforward: dangerous replicators will be
far simpler to design than systems that can thwart them, just as a
bacterium is far simpler than an immune system. We will need tactics
for containing nanotechnology while we learn how to tame it.
One obvious tactic is isolation: the leading force will be able to
contain replicator systems behind multiple walls or in laboratories in
space. Simple replicators will have no intelligence, and they won't be
designed to escape and run wild. Containing them seems no great
challenge.
Better yet, we will be able to design replicators that can't
escape and run wild. We can build them with counters (like those in
cells) that limit them to a fixed number of replications. We can build
them to have requirements for special synthetic "vitamins," or for
bizarre environments found only in the laboratory. Though
replicators could be made tougher and more voracious than any modern
pests, we can also make them useful but harmless. Because we will
design them from scratch, replicators need not have the elementary
survival skills that evolution has built into living cells.
Further, they need not be able to evolve. We can give replicators
redundant copies of their "genetic" instructions, along with repair
mechanisms to correct any mutations. We can design them to stop
working long before enough damage accumulates to make a lasting
mutation a significant possibility. Finally, we can design them in
ways that would hamper evolution even if mutations could occur.
Experiments show that most computer programs (other than specially
designed AI programs,*(207) such as Dr. Lenat's EURISKO) seldom
respond to mutations by changing slightly; instead, they simply
fail. Because they cannot vary in useful ways, they cannot evolve.
Unless they are specially designed, replicators directed by
nanocomputers will share this handicap. Modern organisms are fairly
good at evolving partly because they descend from ancestors that
evolved. They are evolved to evolve; this is one reason for the
complexities of sexual reproduction and the shuffling of chromosome
segments during the production of sperm and egg cells. We can simply
neglect to give replicators similar talents.*(208)
It will be easy for the leading force to make replicating assemblers
useful, harmless, and stable. Keeping assemblers from being stolen and
abused is a different and greater problem, because it will be a game
played against intelligent opponents. As one tactic, we can reduce the
incentive to steal assemblers by making them available in safe
forms. This will also reduce the incentive for other groups to develop
assemblers independently. The leading force, after all, will be
followed by trailing forces.
-
Limited Assemblers
-
In Chapter 4, I described how a system of assemblers in a vat
could build an excellent rocket engine. I also pointed out that we
will be able to make assembler systems that act like seeds,
absorbing sunlight and ordinary materials and growing to become almost
anything. These special-purpose systems will not replicate themselves,
or will do so only a fixed number of times. They will make only what
they were programmed to make, when they are told to make it. Anyone
lacking special assembler-built tools would be unable to reprogram
them to serve other purposes.
Using limited assemblers of this sort, people will be able to make
as much as they want of whatever they want, subject to limits built
into the machines. If none is programmed to make nuclear weapons, none
will; if none is programmed to make dangerous replicators, none
will. If some are programmed to make houses, cars, computers,
toothbrushes, and whatnot, then these products can become cheap and
abundant. Machines built by limited assemblers will enable us to
open space, heal the biosphere, and repair human cells. Limited
assemblers can bring almost unlimited wealth to the people of the
world.
This tactic will ease the moral pressure to make unlimited
assemblers available immediately. But limited assemblers will still
leave legitimate needs unfulfilled. Scientists will need freely
programmable assemblers to conduct studies; engineers will need them
to test designs. These needs can be served by sealed assembler
laboratories.
-
Sealed Assembler Laboratories
-
Picture a computer accessory the size of your thumb, with a
state-of-the-art plug on its bottom. Its surface looks like boring
gray plastic, imprinted with a serial number, yet this sealed
assembler lab is an assembler-built object that contains many
things. Inside, sitting above the plug, is a large nanoelectronic
computer running advanced molecular-simulation software (based on
the software developed during assembler development). With the
assembler lab plugged in and turned on, your assembler-built home
computer displays a three-dimensional picture of whatever the lab
computer is simulating, representing atoms as colored spheres. With
a joystick, you can direct the simulated assembler arm to build
things. Programs can move the arm faster, building elaborate
structures on the screen in the blink of an eye. The simulation always
works perfectly, because the nanocomputer cheats: as you make the
simulated arm move simulated molecules, the computer directs an actual
arm to move actual molecules. It then checks the results whenever
needed to correct its calculations.*(209)
The end of this thumb-sized object holds a sphere built in many
concentric layers. Fine wires carry power and signals through the
layers; these let the nanocomputer in the base communicate with the
devices at the sphere's center. The outermost layer consists of
sensors. Any attempt to remove or puncture it triggers a signal to a
layer near the core. The next layer in is a thick spherical shell of
pre-stressed diamond composite, with its outer layers stretched and
its inner layers compressed. This surrounds a layer of thermal
insulator which in turn surrounds a peppercorn-sized spherical shell
made up of microscopic, carefully arranged blocks of metal and
oxidizer. These are laced with electrical igniters. The outer sensor
layer, if punctured, triggers these igniters. The metal-and-oxidizer
demolition charge then burns in a fraction of a second, producing a
gas of metal oxides denser than water and almost as hot as the surface
of the Sun. But the blaze is tiny; it swiftly cools, and the diamond
sphere confines its great pressure.
This demolition charge surrounds a smaller composite shell, which
surrounds another layer of sensors, which can also trigger the
demolition charge. These sensors surround the cavity which contains
the actual sealed assembler lab.
These elaborate precautions justify the term "sealed." Someone
outside cannot open the lab space without destroying the contents, and
no assemblers or assembler-built structures can escape from within.
The system is designed to let out information, but not dangerous
replicators or dangerous tools. Each sensor layer*(210) consists of
many redundant layers of sensors, each intended to detect any possible
penetration, and each making up for possible flaws in the others.
Penetration, by triggering the demolition charge, raises the lab to
a temperature beyond the melting point of all possible substances
and makes the survival of a dangerous device impossible. These
protective mechanisms all gang up on something about a millionth their
size- that is, on whatever will fit in the lab, which provides a
spherical work space no wider than a human hair.
Though small by ordinary standards, this work space holds room
enough for millions of assemblers and thousands of trillions of atoms.
These sealed labs will let people build and test devices, even
voracious replicators, in complete safety. Children will use the atoms
inside them as a construction set with almost unlimited parts.
Hobbyists will exchange programs for building various gadgets.
Engineers will build and test new nanotechnologies. Chemists,
materials scientists, and biologists will build apparatus and run
experiments. In labs built around biological samples, biomedical
engineers will develop and test early cell repair machines.
In the course of this work, people will naturally develop useful
designs, whether for computer circuits, strong materials, medical
devices, or whatever. After a public review of their safety, these
things could be made available outside the sealed labs by
programming limited assemblers to make them. Sealed labs and limited
assemblers will form a complementary pair: The first will let us
invent freely; the second will let us enjoy the fruits of our
invention safely. The chance to pause between design and release
will help us avoid deadly surprises.
Sealed assembler labs will enable the whole of society to apply
its creativity to the problems of nanotechnology. And this will
speed our preparations for the time when an independent force learns
how to build something nasty.
-
Hiding Information
-
In another tactic for buying time, the leading force can attempt
to burn the bridge it built from bulk to molecular technology. This
means destroying the records of how the first assemblers were made (or
making the records thoroughly inaccessible). The leading force may
be able to develop the first, crude assemblers in such a way that no
one knows the details of more than a small fraction of the whole
system. Imagine that we develop assemblers by the route outlined in
Chapter 1. The protein machines that we use to build the first crude
assemblers will then promptly become obsolete. If we destroy the
records of the protein designs,*(211) this will hamper efforts to
duplicate them, yet will not hamper further progress in
nanotechnology.
If sealed labs and limited assemblers are widely available, people
will have little scientific or economic motivation to redevelop
nanotechnology independently, and burning the bridge from bulk
technology will make independent development more difficult. Yet these
can be no more than delaying tactics. They won't stop independent
development; the human urge for power will spur efforts which will
eventually succeed. Only detailed, universal policing on a
totalitarian scale could stop independent development indefinitely. If
the policing were conducted by anything like a modern government, this
would be a cure roughly as dangerous as the disease. And even then,
would people maintain perfect vigilance forever?
It seems that we must eventually learn to live in a world with
untrustworthy replicators. One sort of tactic would be to hide
behind a wall or to run far away. But these are brittle methods:
dangerous replicators might breach the wall or cross the distance, and
bring utter disaster. And, though walls can be made proof against
small replicators, no fixed wall will be proof against large-scale,
organized malice.*(212) We will need a more robust, flexible approach.
-
Active Shields
-
It seems that we can build nanomachines that act somewhat like the
white blood cells of the human immune system: devices that can fight
not just bacteria and viruses, but dangerous replicators of all sorts.
Call an automated defense of this sort an active shield, to
distinguish it from a fixed wall.
Unlike ordinary engineering systems, reliable active shields must do
more than just cope with nature or clumsy users. They must also cope
with a far greater challenge- with the entire range of threats that
intelligent forces can design and build under prevailing
circumstances. Building and improving prototype shields will be akin
to running both sides of an arms race on a laboratory scale. But the
goal here will be to seek the minimum requirements for a defense
that reliably prevails.
In Chapter 5, I described how Dr. Lenat and his EURISKO program
evolved successful fleets to fight according to the rules of a
naval-warfare simulation game. In a similar way, we can make into a
game the deadly serious effort to develop reliable shields, using
sealed assembler labs of various sizes as playing fields. We can
turn loose a horde of engineers, computer hackers, biologists,
hobbyists, and automated engineering systems, all invited to pit their
systems against one another in games limited only by the initial
conditions, the laws of nature, and the walls of the sealed labs.
These competitors will evolve threats and shields in an open-ended
series of micro-battles. When replicating assemblers have brought
abundance, people will have time enough for so important a game.
Eventually we can test promising shield systems in Earthlike
environments in space. Success will make possible a system able to
protect human life and Earth's biosphere from the worst that a fistful
of loose replicators can do.
-
IS SUCCESS POSSIBLE?
-
With our present uncertainties, we cannot yet describe either
threats or shields with any accuracy. Does this mean we can't have any
confidence that effective shields are possible? Apparently we can;
there is a difference, after all, between knowing that something is
possible and knowing how to do it. And in this case, the world holds
examples of analogous successes.
There is nothing fundamentally novel about defending against
invading replicators; life has been doing it for ages. Replicating
assemblers, though unusually potent, will be physical systems not
unlike those we already know. Experience suggests that they can be
controlled.
Viruses are molecular machines that invade cells; cells use
molecular machines (such as restriction enzymes and antibodies) to
defend against them. Bacteria are cells that invade organisms;
organisms use cells (such as white blood cells) to defend against
them. Similarly, societies use police to defend against criminals
and armies to defend against invaders. On a less physical level, minds
use meme systems such as the scientific method to defend against
nonsense, and societies use institutions such as courts to defend
against the power of other institutions.
The biological examples in the last paragraph show that even after a
billion-year arms race, molecular machines have maintained
successful defenses against molecular replicators. Failures have
been common too, but the successes do indicate that defense is
possible. These successes suggest that we can indeed use
nanomachines to defend against nanomachines. Though assemblers will
bring many advances, there seems no reason why they should permanently
tip the balance against defense.
The examples given above- some involving viruses, some involving
institutions- are diverse enough to suggest that successful defense
rests on general principles. One might ask, Why do all these
defenses succeed? But turn the question around: Why should they
fail? Each conflict pits similar systems against each other, giving
the attacker no obvious advantage.*(213) In each conflict, moreover,
the attacker faces a defense that is well established. The defenders
fight on home ground, giving them advantages such as prepared
positions, detailed local knowledge, stockpiled resources, and
abundant allies- when the immune system recognizes a germ, it can
mobilize the resources of an entire body. All these advantages are
general and basic, having little to do with the details of a
technology. We can give our active shields the same advantages over
dangerous replicators. And they need not sit idle while dangerous
weapons are amassed, any more than the immune system sits idle while
bacteria multiply.
It would be hard to predict the outcome of an open-ended arms race
between powers equipped with replicating assemblers. But before this
situation can arise, the leading force seems likely to acquire a
temporary but overwhelming military advantage. If the outcome of an
arms race is in doubt, then the leading force will likely use its
strength to ensure that no opponents are allowed to catch up. If it
does so, then active shields will not have to withstand attacks backed
by the resources of half a continent or half a solar system; they will
instead be like a police force or an immune system, facing attacks
backed only by whatever resources can be gathered in secret within the
protected territory.
In each case of successful defense that I cited above, the attackers
and the shields have developed through broadly similar processes.
The immune system, shaped by genetic evolution, meets threats also
shaped by genetic evolution. Armies, shaped by human minds, also
meet similar threats. Likewise, both active shields and dangerous
replicators will be shaped by memetic evolution. But if the leading
force can develop automated engineering systems that work a
millionfold faster than human engineers, and if it can use them for
a single year, then it can build active shields based on a million
years' worth of engineering advance. With such systems we may be
able to explore the limits of the possible well enough to build a
reliable shield against all physically possible threats.
Even without our knowing the details of the threats and the shields,
there seems reason to believe that shields are possible. And the
examples of memes controlling memes and of institutions controlling
institutions also suggest that AI systems can control AI systems.
In building active shields, we will be able to use the power of
replicators and AI systems to multiply the traditional advantages of
the defending force: we can give it overwhelming strength through
abundant, replicator-built hardware with designs based on the
equivalent of a million-year lead in technology. We can build active
shields having strength and reliability that will put past systems
to shame.
Nanotechnology and artificial intelligence could bring the
ultimate tools of destruction, but they are not inherently
destructive. With care, we can use them to build the ultimate tools of
peace.
12
Strategies and Survival
-
He that will not apply new remedies must expect new evils; for
time is the greatest innovator.
-FRANCIS BACON
-
IN EARLIER CHAPTERS I have stuck close to the firm ground of
technological possibility. Here, however, I must venture further
into the realm of politics and human action. This ground is softer,
but technological facts and evolutionary principles still provide firm
points on which to stand and survey the territory.
The technology race, driven by evolutionary pressures, is carrying
us toward unprecedented dangers; we need to find strategies for
dealing with them. Since we see such great dangers ahead, it makes
sense to consider stopping our headlong rush. But how can we?
-
Personal Restraint
-
As individuals, we could refrain from doing research that leads
toward dangerous capabilities. Indeed, most people will refrain, since
most are not researchers in the first place. But this strategy won't
stop advances: in our diverse world, others will carry the work
forward.
-
Local Suppression
-
A strategy of personal restraint (at least in this matter) smacks of
simple inaction. But what about a strategy of local political
action, of lobbying for laws to suppress certain kinds of research?
This would be personal action aimed at enforcing collective
inaction. Although it might succeed in suppressing research in a city,
a district, a country, or an alliance, this strategy cannot help us
guide the leading force; instead, it would let some force beyond our
control take the lead. A popular movement of this sort can halt
research only where the people hold the power, and its greatest
possible success would merely open the way for a more repressive state
to become the leading force.
Where nuclear weapons are concerned, arguments can be made for
unilateral disarmament and nonviolent (or at least non-nuclear)
resistance. Nuclear weapons can be used to smash military
establishments and spread terror, but they cannot be used to occupy
territory or rule people- not directly. Nuclear weapons have failed to
suppress guerrilla warfare and social unrest, so a strategy of
disarmament and resistance makes some degree of sense.
The unilateral suppression of nanotechnology and AI, in contrast,
would amount to unilateral disarmament in a situation where resistance
cannot work. An aggressive state could use these technologies to seize
and rule (or exterminate) even a nation of Gandhis, or of armed and
dedicated freedom fighters.
This deserves emphasis. Without some novel way to reform the world's
oppressive states, simple research-suppression movements cannot have
total success. Without a total success, a major success would mean
disaster for the democracies. Even if they got nowhere, efforts of
this sort would absorb the work and passion of activists, wasting
scarce human resources on a futile strategy. Further, efforts at
suppression would alienate concerned researchers, stirring fights
between potential allies and wasting further human resources. Its
futility and divisiveness make this a strategy to be shunned.
Nonetheless, suppression has undeniable appeal. It is simple and
direct: "Danger coming? Let's stop it!" Further, successes in local
lobbying efforts promise short-term gratification: "Danger coming?
We can stop it here and now, for a start!" The start would be a
false start, but not everyone will notice. The idea of simple
suppression seems likely to seduce many minds. After all, local
suppression of local dangers has a long, successful tradition;
stopping a local polluter, for example, reduces local pollution.
Efforts at local suppression of global dangers will seem similar,
however different the effects may be. We will need local
organization and political pressure, but they must be built around a
workable strategy.
-
Global Suppression Agreements
-
In a more promising approach, we could apply local pressure for
the negotiation of a verifiable, worldwide ban. A similar strategy
might have a chance in the control of nuclear weapons. But stopping
nanotechnology and artificial intelligence would pose problems of a
different order, for at least two reasons.
First, these technologies are less well-defined than nuclear
weapons: because current nuclear technology demands certain isotopes
of rare metals, it is distinct from other activities. It can be
defined and (in principle) banned. But modern biochemistry leads in
small steps to nanotechnology, and modern computer technology leads in
small steps to AI. No line defines a natural stopping point. And since
each small advance will bring medical, military, and economic
benefits, how could we negotiate a worldwide agreement on where to
stop?
Second, these technologies are more potent than nuclear weapons:
because reactors and weapons systems are fairly large, inspection
could limit the size of a secret force and thus limit its strength.
But dangerous replicators will be microscopic, and AI software will be
intangible. How could anyone be sure that some laboratory somewhere
isn't on the verge of a strategic breakthrough? In the long run, how
could anyone even be sure that some hacker in a basement isn't on
the verge of a strategic breakthrough? Ordinary verification
measures won't work, and this makes negotiation and enforcement of a
worldwide ban almost impossible.
Pressure for the right kinds of international agreements will make
our path safer, but agreements simply to suppress dangerous advances
apparently won't work. Again, local pressure must be part of a
workable strategy.
-
Global Suppression by Force
-
If peaceful agreements won't work, one might consider using military
force to suppress dangerous advances. But because of verification
problems, military pressure alone would not be enough. To suppress
advances by force would instead require that one power conquer and
occupy hostile powers*(214) armed with nuclear weapons- hardly a
safe policy. Further, the conquering power would itself be a major
technological force with massive military power and a demonstrated
willingness to use it. Could this power then be trusted to suppress
its own advances? And even if so, could it be trusted to maintain
unending, omnipresent vigilance over the whole world? If not, then
threats will eventually emerge in secret, and in a world where open
work on active shields has been prevented. The likely result would
be disaster.
Military strength in the democracies has great benefits, but
military strength alone cannot solve our problem. We cannot win safety
through a strategy of conquest and research suppression.
These strategies for stopping research- whether through personal
inaction, local inaction, negotiated agreement, or world conquest- all
seemed doomed to fail. Yet opposition to advances will have a role
to play, because we will need selective, intelligently targeted
delay to postpone threats until we are prepared for them. Pressure
from alert activists will be essential, but to help guide advance, not
to halt it.
-
Unilateral Advance
-
If attempts to suppress research in AI and nanotechnology seem
futile and dangerous, what of the opposite course- an all-out,
unilateral effort? But this too presents problems. We in the
democracies probably cannot produce a major strategic breakthrough
in perfect secrecy. Too many people would be involved for too many
years. Since the Soviet leadership would learn of our efforts, their
reaction becomes an obvious concern, and they would surely view a
great breakthrough on our part as a great threat. If nanotechnology
were being developed as part of a secret military program, their
intelligence analysts would fear the development of a subtle but
decisive weapon, perhaps based on programmable "germs." Depending on
the circumstances, our opponents might choose to attack while they
still could. It is important that the democracies keep the lead in
these technologies, but we will be safest if we can somehow combine
this strength with clearly nonthreatening policies.
-
Balance of Power
-
If we follow any of the strategies above we will inevitably stir
strong conflict. Attempts to suppress nanotechnology and AI will pit
the would-be suppressors against the vital interests of researchers,
corporations, military establishments, and medical patients.
Attempts to gain unilateral advantage through these technologies
will pit the cooperating democracies against the vital interests of
our opponents. All strategies will stir conflict, but need all
strategies split Western societies or the world so badly?
In search of a middle path, we might seek a balance of power based
on a balance of technology. This would seemingly extend a situation
that has kept a measure of peace for four decades. But the key word
here is "seemingly": the coming breakthroughs will be too abrupt and
destabilizing for the old balance to continue. In the past, a
country could suffer a technological lag of several years and yet
maintain a rough military balance. With swift replicators or
advanced AI, though, a lag of a single day could be fatal. A stable
balance seems too much to hope for.
-
Cooperative Development
-
There is, in principle, a way to ensure a technological balance
between the cooperating democracies and Soviet bloc: we could
develop the technologies cooperatively, sharing our tools and
information. Though this has obvious problems, it is at least somewhat
more practical than it may sound.
Is cooperation possible to negotiate? Failed attempts to negotiate
effective arms control treaties immediately leap to mind, and
cooperation may seem even more complicated and difficult to arrange.
But is it? In arms control, each side is attempting to hinder the
other's actions; this reinforces their adversarial relationship.
Further, it stirs conflicts within each camp between groups that favor
arms limitation and groups that exist to build arms. Worse yet, the
negotiations revolve around words and their meanings, but each side
has its own language and an incentive to twist meanings to suit
itself.
Cooperation, in contrast, involves both sides working toward a
shared goal; this tends to blur the adversarial nature of the
relationship. Further, it may lessen the conflicts within each camp,
since cooperative efforts would create projects, not destroy them.
Finally, both sides discuss their efforts in a shared language- the
language of mathematics and diagrams used in science and
engineering. Also, cooperation has clear-cut, visible results. In
the mid-1970S, the U.S. and U.S.S.R. flew a joint space mission, and
until political tensions grew they were laying tentative plans for a
joint space station. These were not isolated incidents, in space or on
the ground; joint projects and technical exchange have gone on for
years. For all its problems, technological cooperation has proved at
least as easy as arms control- perhaps even easier, considering the
great effort poured into the latter.
Curiously, where AI and nanotechnology are concerned, cooperation
and effective arms control would have a basic similarity. To verify an
arms control agreement would require constant, intimate inspection
of each side's laboratories by the other's experts- a relationship
as close as the most thorough cooperation imaginable.
But what would cooperation accomplish? It might ensure balance,
but balance will not ensure stability. If two gunmen face each other
with weapons drawn and fears high, their power is balanced, but the
one that shoots first can eliminate the other's threat. A
cooperative effort in technology development, unless carefully planned
and controlled, would give each side fearsome weapons while
providing neither side with a shield. Who could be sure that neither
side would find a way to strike a disarming blow with impunity?
And even if one could guarantee this, what about the problem of
other powers- and hobbyists, and accidents?
In the last chapter I described a solution to these problems: the
development, testing, and construction of active shields. They offer a
new remedy for a new problem, and no one has yet suggested a plausible
alternative to them. Until someone does, it seems wise to consider how
they might be built and whether they might make possible a strategy
that can work.
-
A SYNTHESIS OF STRATEGIES
-
Personal restraint, local action, selective delay, international
agreement, unilateral strength, and international cooperation- all
these strategies can help us in an effort to develop active shields.
Consider our situation today. The democracies have for decades led
the world in most areas of science and technology; we lead today in
computer software and biotechnology. Together, we are the leading
force. There seems no reason why we cannot maintain that lead and
use it.
As discussed in the last chapter, the leading force will be able
to use several tactics to handle the assembler breakthrough. These
include using sealed assembler labs and limited assemblers, and
maintaining secrecy regarding the details of initial assembler
development. In the time we buy through these (and other) policies, we
can work to develop active shields able to give us permanent
protection against the new dangers. This defines a goal. To reach
it, a two-part strategy seems best.
The first part involves action within the cooperating democracies.
We need to maintain a lead that is comfortable enough for us to
proceed with caution; if we felt we might lose the race, we might well
panic. Proceeding with caution means developing trustworthy
institutions for managing both the initial breakthroughs and the
development of active shields. The shields we develop, in turn, must
be designed to help us secure a future worth living in, a future
with room for diversity.
The second part of this strategy involves policies toward
presently hostile powers. Here, our aim must be to keep the initiative
while minimizing the threat we present. Technological balance will not
work, and we cannot afford to give up our lead. This leaves strength
and leadership as our only real choice, making a nonthreatening
posture doubly difficult to achieve. Here again we have need for
stable, trustworthy institutions: if we can give them a great built-in
inertia regarding their objectives, then perhaps even our opponents
will have a measure of confidence in them.
To reassure our opponents (and ourselves!) these institutions should
be as open as possible,*(215) consistent with their mission. We may
also manage to build institutions that offer a role for Soviet
cooperation. By inviting their participation, even if they refuse
the terms we offer, we would offer some measure of reassurance
regarding our intentions. If the Soviets were to accept, they would
gain a public stake in our joint success.
Still, if the democracies are strong when the breakthroughs
approach, and if we avoid threatening any government's control over
its own territory, then our opponents will presumably see no advantage
in attacking. Thus, we can probably do without cooperation, if
necessary.
-
ACTIVE SHIELDS VS. SPACE WEAPONS
-
It may be useful to consider how we might apply the idea of active
shields in more conventional fields. Traditionally, defense has
required weapons that are also useful for offense. This is one
reason why "defense" has come to mean "war-making ability," and why
"defense" efforts give opponents reason for fear. Presently proposed
space-based defenses will extend this pattern. Almost any defensive
system that can destroy attacking missiles could also destroy an
opponent's defenses- or enforce a space blockade, preventing an
opponent from building defenses in the first place. Such "defenses"
smell of offense, as seemingly they must, to do their job. And so
the arms race gathers itself for another dangerous leap.
Must defense and offense be so nearly inseparable? History makes
it seem so. Walls only halt invaders when defended by warriors, but
warriors can themselves march off to invade other lands. When we
picture a weapon, we naturally picture human hands aiming it*(216) and
human whim deciding when to fire- and history has taught us to fear
the worst.
Yet today, for the first time in history, we have learned how to
build defensive systems that are fundamentally different from such
weapons. Consider a space-based example. We now can design devices
that sense (looks like a thousand missiles have just been launched),
assess (this looks like an attempted first strike) and act (try to
destroy those missiles!). If a system will fire only at massive
flights of missiles, then it cannot be used for offense or a space
blockade. Better yet, it could be made incapable of discriminating
between attacking sides. Though serving the strategic interests of its
builders, it would not be subject to the day-to-day command of
anyone's generals. It would just make space a hazardous environment
for an attacker's missiles. Like a sea or a mountain range in
earlier wars, it would threaten neither side while providing each with
some protection*(217) against the other.
Though it would use weapons technologies (sensors, trackers, lasers,
homing projectiles, and such), this defense wouldn't be a weapons
system, because its role would be fundamentally different. Systems
of this sort need a distinctive name: they are, in fact, a sort of
active shield- a term that can describe any automated or semiautomated
system designed to protect without threatening. By defending both
sides while threatening neither, active shields could weaken the cycle
of the arms race.
The technical, economic, and strategic issues raised by active
shields are complex, and they may or may not be practical in the
preassembler era. If they are practical, then there will be several
possible approaches to building them. In one approach, the cooperating
democracies would build shields unilaterally. To enable other
nations to verify what the system will and (more important) won't
do, we could allow multilateral inspection of key designs, components,
and production steps. We needn't give away all the technologies
involved, because know-what isn't the same as know-how. In a different
approach, we would build shields jointly, limiting technology
transfer*(218) to the minimum required for cooperation and
verification (using principles discussed in the Notes).
We have more chance of banning space weapons than we do of banning
nanotechnology, and this might even be the best way to minimize our
near-term risks. In choosing a long-term strategy for controlling
the arms race, though, we must consider more than the next step. The
analysis I have outlined in this chapter suggests that traditional
arms control approaches, based on negotiating verifiable
limitations, cannot cope with nanotechnology. If this is the case,
then we need to develop alternative approaches. Active shields-
which seem essential, eventually- may offer a new, stabilizing
alternative to an arms race in space. By exploring this alternative,
we can explore basic issues common to all active shields.*(219) If
we then develop them, we will gain experience and build
institutional arrangements that may later prove essential to our
survival.
Active shields are a new option based on new technologies. Making
them work will require a creative, interdisciplinary synthesis of
ideas in engineering, strategy, and international affairs. They
offer fresh choices that may enable us to avoid old impasses. They
apparently offer an answer to the ancient problem of protecting
without threatening- but not an easy answer.
-
POWER, EVIL, INCOMPETENCE, AND SLOTH
-
I have outlined how nanotechnology and advanced AI will give great
power to the leading force- power that can be used to destroy life, or
to extend and liberate it. Since we cannot stop these technologies, it
seems that we must somehow cope with the emergence of a
concentration of power greater than any in history.
We will need a suitable system of institutions. To handle complex
technologies safely, this system must have ways to judge the
relevant facts. To handle great power safely, it must incorporate
effective checks and balances, and its purposes and methods must be
kept open to public scrutiny. Finally, since it will help us lay the
foundations for a new world, it had best be guided by our shared
interests, within a framework of sound principles.
We won't start from scratch; we will build on the institutions we
have. They are diverse. Not all of our institutions are
bureaucracies housed in massive gray buildings; they include such
diffuse and lively institutions as the free press, the research
community, and activist networks. These decentralized institutions
help us control the gray, bureaucratic machines.
In part, we face a new version of the ancient and general problem of
limiting the abuse of power. This presents no great, fundamental
novelty, and the centuries-old principles and institutions of
liberal democracy suggest how it may be solved. Democratic governments
already have the physical power to blast continents and to seize,
imprison, and kill their citizens. But we can live with these
capabilities because these governments are fairly tame and stable.
The coming years will place greater burdens on our institutions. The
principles of representative government, free speech, due process, the
rule of law, and protection of human rights will remain crucial. To
prepare for the new burdens, we will need to extend and reinvigorate
these principles and the institutions that support them; protecting
free speech regarding technical matters may be crucial. Though we face
a great challenge, there is reason to hope that we can meet it.
There are also, of course, obvious reasons for doubting that we
can meet it. But despair is contagious and obnoxious and leaves people
depressed. Besides, despair seems unjustified, despite familiar
problems: Evil- are we too wicked to do the right thing? Incompetence-
are we too stupid to do the right thing? Sloth- are we too lazy to
prepare?
While it would be rash to predict a rosy future, these problems do
not seem insurmountable.
Democratic governments are big, sloppy, and sometimes responsible
for atrocities, yet they do not seem evil, as a whole, though they may
contain people who deserve the label. In fact, their leaders gain
power largely by appearing to uphold conventional ideas of good. Our
chief danger is that policies that seem good may lead to disaster,
or that truly good policies won't be found, publicized, and
implemented in time to take effect. Democracies suffer more from sloth
and incompetence than from evil.
Incompetence will of course be inevitable, but need it be fatal?
We human beings are by nature stupid and ignorant, yet we sometimes
manage to combine our scraps of competence and knowledge to achieve
great things. No one knew how to get to the Moon, and no one ever
learned, yet a dozen people have walked its surface. We have succeeded
in technical matters because we have learned to build institutions
that draw many people together to generate and test ideas. These
institutions gain reliability through redundancy, and the quality of
their results depends largely on how much we care and how hard we
work. When we focus enough attention and resources on reliability,
we often succeed. This is why the Moon missions succeeded without a
fatality in space, and why no nuclear weapon has ever been launched or
detonated by accident. And this is why we may manage to handle
nanotechnology and advanced AI with sufficient care to ensure a
competent job. Erratic people of limited competence can join to form
stable, competent institutions.
Sloth- intellectual, moral, and physical- seems perhaps our greatest
danger. We can only meet great challenges with great effort. Will
enough people make enough effort? No one can say, because no one can
speak for everyone else. But success will not require a sudden,
universal enlightenment and mobilization. It will require only that
a growing community of people strive to develop, publicize, and
implement workable solutions- and that they have a good and growing
measure of success.
This is not so implausible. Concern about technology has become
widespread, as has the idea that accelerating change will demand
better foresight. Sloth will not snare everyone, and misguided
thinkers will not misdirect everyone's effort. Deadly pseudo-solutions
(such as blocking research) will lose the battle of ideas if enough
people debunk them. And though we face a great challenge, success will
make possible the fulfillment of great dreams. Great hopes and fears
may stir enough people to enable the human race to win through.
Passionate concern and action will not be enough; we will also
need sound policies. This will require more than good intentions and
clear goals: we must also trace the factual connections in the world
that will relate what we do to what we get. As we approach a
technological crisis of unprecedented complexity, it makes sense to
try to improve our institutions for judging important technical facts.
How else can we guide the leading force and minimize the threat of
terminal incompetence?
Institutions evolve. To evolve better fact-finding institutions,
we can copy, adapt, and extend our past successes. These include the
free press, the scientific community, and the courts. All have their
virtues, and some of these virtues can be combined.
13
Finding the Facts
-
Fear cannot be banished, but it can be calm and without panic; and
it can be mitigated by reason and evaluation.
-VANNEVAR BUSH
-
SOCIETY NEEDS BETTER WAYS to understand technology- this has long
been obvious. The challenges ahead simply make our need more urgent.
The promise of technology lures us onward, and the pressure of
competition makes stopping virtually impossible. As the technology
race quickens, new developments sweep toward us faster, and a fatal
mistake grows more likely. We need to strike a better balance
between our foresight and our rate of advance. We cannot do much to
slow the growth of technology, but we can speed the growth of
foresight. And with better foresight, we will have a better chance
to steer the technology race in safe directions.
Various approaches to guiding technology have been suggested. "The
people must control technology" is a plausible slogan, but it has
two possible meanings. If it means that we must make technology
serve human needs, then it makes good sense. But if it means that
the people as a whole must make technical decisions, then it makes
very little sense. The electorate cannot judge the intricate links
between technology, economy, environment, and life; people lack the
needed knowledge. The people themselves agree: according to a U.S.
National Science Foundation survey,*(220) 85 percent of U.S. adults
believe that most citizens lack the knowledge needed to choose which
technologies to develop. The public generally leaves technical
judgments to technical experts.
Unfortunately, leaving judgment to experts causes problems. In
Advice and Dissent,*(221) Primack and von Hippel point out that "to
the extent that the Administration can succeed in keeping
unfavorable information quiet and the public confused, the public
welfare can be sacrificed with impunity to bureaucratic convenience
and private gain." Regulators suffer more criticism when a new drug
causes a single death than they do when the absence of a new drug
causes a thousand deaths. They misregulate accordingly. Military
bureaucrats have a vested interest in spending money, hiding mistakes,
and continuing their projects. They mismanage accordingly. This sort
of problem is so basic and natural that more examples are hardly
needed. Everywhere, secrecy and fog make bureaucrats more comfortable;
everywhere, personal convenience warps factual statements on matters
of public concern. As technologies grow more complex and important,
this pattern grows more dangerous.
Some authors consider rule by secretive technocrats to be
virtually inevitable. In Creating Alternative Futures, Hazel Henderson
argues*(222) that complex technologies "become 'inherently'
totalitarian" (her 'italics') because neither voters nor legislators
can understand them. In The Human Future Revisited, Harrison Brown
likewise argues*(223) that the temptation to bypass democratic
processes in solving complex crises brings the danger "that if
industrial civilization survives it will become increasingly
totalitarian in nature." If this were so, it would likely mean our
doom: we cannot stop the technology race, and a world of
totalitarian states based on advanced technology needing neither
workers nor soldiers might well discard most of the population.
Fortunately, democracy and liberty have met comparable challenges
before. States grew too complex for direct democracy, but
representative government evolved. State power threatened to crush
liberty, but the rule of law evolved. Technology has grown complex,
but this gives us no reason to ignore the people, discard the law, and
hail a dictator. We need ways to handle technical complexity in a
democratic framework, using experts as instruments to clarify our
vision without giving them control of our lives. But technical experts
today are mired in a system of partisan feuding.
-
A MESS OF EXPERTS
-
Government and industry- and their critics- commonly appoint
expert committees that meet in secret, if they meet at all. These
committees claim credibility based on who they are, not on how they
work. Opposed groups recruit opposed Nobel laureates.
To gain influence in our mass democracy, groups try to outshout
one another. When their views have corporate appeal, they take them to
the public through advertising campaigns. When their views have
pork-barrel appeal, they take them to legislatures through lobbying.
When their views have dramatic appeal, they take them to the public
through media campaigns. Groups promote their pet experts, the
battle goes public, and quiet scientists and engineers are drowned
in the clamor.
As the public conflict grows, people come to doubt expert
pronouncements. They judge statements the obvious way, by their
source. ("Of course she claims oil spills are harmless- she works
for Exxon." "Of course he says Exxon lies- he works for Nader.")
When established experts lose credibility, demagogues can join the
battle on an equal footing. Reporters- eager for controversy, striving
for fairness, and seldom guided by technical backgrounds- carry all
sides straight to the public. Cautious statements by scrupulous
scientists make little impression; other scientists see no choice
but to adopt the demagogues' style. Debates become sharp and angry,
divisions grow, and the smoke of battle obscures the facts.
Paralysis or folly often follows.
Our greatest problem is how we handle problems. Debates rage over
the safety of nuclear power,*(224) coal power, and chemical wastes.
Well-meaning groups backed by impressive experts clash again and again
over dull, technical facts- dull that is, save for their importance:
What are the effects of low-level radiation, and how likely is a
reactor meltdown? What are the causes and effects of acid rain? How
well could space-based defenses block missile attacks? Do five cases
of leukemia within three miles of a particular waste dump show a
deadly hazard, or merely the workings of chance?
Greater issues lie ahead: How safe is this replicator? Will this
active shield system be safe and secure? Will this biostasis procedure
be reversible? Can we trust this AI system?
Disputes about technical facts feed broader disputes about policy.
People may have differing values (which would you rather have,
encephalitis or pesticide poisoning?) but their views of relevant
facts often differ still more. (How often do these mosquitoes carry
encephalitis? How toxic is this pesticide?) When different views of
boring facts lead to disagreements about important policies, people
may wonder, "How can they oppose us on this vital issue unless they
have bad motives?" Disputes over facts*(225) can thus turn potential
allies against one another. This hampers our efforts to understand and
solve our problems.
People have disputed facts for millennia; only the prominence of
technical disputes is new. Societies have evolved methods for
judging facts about people. These methods suggest how we might judge
facts about technology.
-
FROM FEUDS TO DUE PROCESS
-
Throughout history, groups have evolved ways to resolve disputes;
the alternative has been feuds, open-ended and often deadly.
Medieval Europeans used several procedures, all better than endless
feuding:
They used trial by battle: opponents fought, and the law
vindicated the victor.
They used compurgation: neighbors swore to the honesty of the
accused; if enough swore, the charges were dropped.
They used trial by ordeal: in one, the accused was bound and
thrown in a river; those who sank were innocent, those who floated,
guilty.
They used judgment by secretive committees: the king's councilors
would meet to judge and pass sentence as seemed fit. In England,
they met in a room called the Star Chamber.
These methods supposedly determined who did what- the facts about
human events- but all had serious shortcomings. Today we use similar
methods to determine what causes what- the facts about science and
technology:
We use trial by combat in the press: opponents fling sharp words
until one side's case suffers political death. Unfortunately, this
often resembles an endless feud.
We use compurgation: experts swear to certain facts; if enough swear
the same, the facts are declared true.
We use judgment by secretive committees: selected experts meet to
judge facts and recommend such actions as seem fit. In the United
States, they often meet in committees of the National Academy of
Sciences.
Trial by ordeal has passed from fashion, but combat in the press may
well seem like torture to the quiet scientist with self-respect.
The English abolished Star Chamber proceedings in 1641, and they
counted this a great achievement. Trial by combat, compurgation, and
ordeal have likewise become history. We now value due process, at
least when judging people.
Court procedures illustrate the principles of due process:
Allegations must be specific. Both sides must have a chance to speak
and confront each other, to rebut and cross-examine. The process
must be public, to prevent hidden rot. Debate must proceed before a
jury that both sides accept as impartial. Finally, a judge must
referee the process and enforce the rules.
To see the value of due process, imagine its opposite: a process
trampling all these principles would give one side a say and the other
no chance to cross-examine or respond. It would meet in secret,
allow vague smears, and lack a judge to enforce whatever rules might
remain. Jurors would arrive with their decisions made. In short, it
would resemble a lynch mob meeting in a locked barn- or a rigged
committee drafting a report.
Experience shows the value of due process in judging facts about
people; might it also be of value in judging facts about science and
technology? Due process is a basic idea, not restricted to courts of
law. Some AI researchers,*(226) for example, are building
due-process principles into their computer programs. It seems that due
process should be of use in judging technical facts.
In fact, the scientific literature- the chief forum of science-
already embodies a form of due process: In good journals, scientific
statements must be specific. In theory, given enough time and
persistence, all sides may state their views in a dispute, since
journals stand open to controversy. Though opponents may not meet face
to face, they confront each other at a distance; they question and
respond in slow motion, through letters and articles. Referees, like
juries, evaluate evidence and reasoning. Editors, like judges, enforce
rules of procedure. Publication keeps the debate open to public
scrutiny.
In both journals and courts, conflicting ideas are pitted against
one another under rules evolved to ensure a fair, orderly battle.
These rules sometimes fail because they are broken or inadequate,
but they are the best we have developed. Imperfect due process has
proved better than no due process at all.
Why do scientists value refereed journals? Not because they trust
all refereed journals, or trust everything printed in any one of them.
Even the best due-process system won't grind out a stream of pure
truth. Rather, they value refereed journals because they tend to
reflect sound critical discussion. Indeed, they must: because journals
compete with one another for papers, prestige, and readership, the
best journals must be good indeed. Journals grind slowly, yet after
enough rounds of publication and criticism they often grind out
consensus.
Experience proves the value of both courts and journals. Their
underlying similarity suggests that their value stems from a common
source- due process. Due process can fail, but it is still the best
approach known for finding the facts.
Today, courts and journals are not enough. Vital technical
disputes go on and on because we have no rapid, orderly way to bring
out the facts (and to delineate our ignorance). Courts are not
suited to deal with technical questions. Journals are better, but they
still have shortcomings. They took shape in a time of lower technology
and slower advance, evolving to fit the limits of printing, the
speed of mail, and the needs of academic science. But today, in a time
when we desperately need better and swifter technical judgment, we
find ourselves in a world that has telephones, jets, copiers, and
express and electronic mail. Can we use modern technologies to speed
technical debate?
Of course: scientists already use several approaches. Jets bring
scientists from around the globe to conferences where papers are
presented and discussed. But conferences handle controversy poorly:
public decorum and tight schedules limit the vigor and depth of
debate.
Scientists also join informal research networks linked by telephone,
mail, computers, and copying machines; these accelerate exchange and
discussion. But they are essentially private institutions. They,
too, fail to provide a credible, public procedure for thrashing out
differences.
Conferences, journals, and informal networks share some similar
limitations. They typically focus on technical questions of scientific
importance, rather than on technical questions of public-policy
importance. Moreover, they typically focus on scientific questions.
Journals tend to slight technological questions that lack intrinsic
scientific interest; they often treat them as news items not worthy of
checking by referees. Further, our present institutions lack any
balanced way to present knowledge when it is still tangled in
controversy. Though scientific review articles often present and weigh
several sides, they do so from a single author's point of view.
All these shortcomings share a common source: scientific
institutions evolved to advance science, not to sift facts for
policymakers. These institutions serve their purpose well enough,
but they serve other purposes poorly. Though this is no real fading,
it does leave a real need.
-
AN APPROACH
-
We need better procedures for debating technical facts- procedures
that are open, credible, and focused on finding the facts we need to
formulate sound policies. We can begin by copying aspects of other
due-process procedures; we then can modify and refine them in light of
experience. Using modern communications and transportation, we can
develop a focused, streamlined, journal-like process to speed public
debate on crucial facts; this seems half the job. The other half
requires distilling the results of the debate into a balanced
picture of our state of knowledge (and by the same token, of our state
of ignorance). Here, procedures somewhat like those of courts*(227)
seem useful.
Since the procedure (a fact forum) is intended to summarize facts,
each side will begin by stating what it sees as the key facts and
listing them in order of importance. Discussion will begin with the
statements that head each side's list. Through rounds of argument,
cross-examination, and negotiation the referee will seek agreed-upon
statements. Where disagreements remain, a technical panel will then
write opinions, outlining what seems to be known and what still
seems uncertain. The output of the fact forum will include
background arguments, statements of agreement, and the panel's
opinions. It might resemble a set of journal articles capped by a
concise review article- one limited to factual statements, free of
recommendations for policy.
This procedure must differ from that of a court in various ways. For
example, the technical panel- the forum's "jury"- must be
technically competent. Bias might lead a panel to misjudge facts,
but technical incompetence would do equal harm. For this reason, the
"jury" of a fact forum must be selected in a way that might be
dangerous if allowed in courts of law. Since courts wield the power of
the police, we use juries selected from the people as a whole to guard
our liberty. This forces the government to seek approval from a
group of citizens before it punishes someone, thus tying the
government's actions to community standards. A fact forum, however,
will neither punish people nor make public policy. The public will
be free to watch the process and decide whether to believe its
results. This will give people control enough.
Still, to make a fact forum fair and effective, we will need a
good panel-selection procedure. Technical panels will correspond
roughly to the expert committees appointed by governments or to the
referees appointed by journals. To ensure fairness, a panel must be
selected not by a committee, a politician, or a bureaucrat, but by a
process that involves the consent of both sides in the dispute. In
court proceedings, advocates can challenge and reject any jurors who
seem biased; we can use a similar process in selecting the panel for a
fact forum.
Experts who are directly involved in a dispute can't serve on the
panel- they would either bias the panel or split it. The group
sponsoring a fact forum must seek panelists who are knowledgeable in
related fields. This seems practical because the methods of
technical judgment (often based on experiments and calculations) are
quite general. Panelists familiar with the fundamentals of a field
will be able to judge the detailed arguments made by each side's
specialists.
Other parts of the fact forum will also resemble those of courts and
journals. A committee like a journal's editorial group will nominate a
referee and panelists for a dispute. Advocates for each side, like
authors or attorneys, will assemble and present the strongest case
they can.
Despite these similarities, a fact forum will differ from a court:
It will focus on technical questions. It will suggest no actions. It
will lack government power. It will follow technical rules of evidence
and argument. It will differ in endless details of tone and procedure.
The analogy with a court is just that- an analogy, a source for ideas.
A fact forum will also differ from a journal: It will move as fast
as mail, meetings, and electronic messages permit, rather than
delaying exchanges by many months, as in typical journal
publication. It will be convened around an issue, rather than being
established to cover a scientific field. It will summarize knowledge
to aid decisions, rather than serving as a primary source of data
for the scientific community. Although a series of fact forums won't
replace a journal, they will help us find and publicize facts that
could save our lives.
Dr. Arthur Kantrowitz (a member of the National Academy of
Sciences who is accomplished in fields ranging from medical technology
to high-power lasers) originated the concept*(228) I have just
outlined. He at first called it a "board of technical inquiry."
Journalists promptly dubbed it a "science court." I have called it a
"fact forum"; I will reserve the term "science court" for a fact forum
used (or proposed) as a government institution.*(229) Proposals for
due process in technical disputes are still in flux; different
discussions use different terms.
Dr. Kantrowitz's concern with due process arose out of the U.S.
decision to build giant rockets to reach the Moon in one great leap;
he, backed by the findings of an expert committee,*(230) had
recommended that NASA use several smaller rockets to carry
components into a low orbit, then plug them together to build a
vehicle to reach the Moon. This approach promised to save billions
of dollars and develop useful space-construction capabilities as well.
No one answered his arguments, yet he failed to win his case. Minds
were set, politicians were committed, the report was locked in a White
House safe, and the debate was closed. The technical facts were
quietly suppressed in the interests of those who wanted to build a new
generation of giant rockets.
This showed a grave flaw in our institutions- one that persists,
wasting our money and increasing the risk of a disastrous error. Dr.
Kantrowitz soon reached the now obvious conclusion: we need
due-process institutions for airing technical controversies.
Dr. Kantrowitz pursued this goal (in its science-court form) through
discussions, writings, studies, and conferences. He won endorsements
for the science court idea from Ford, Carter, and Reagan- as
candidates. As Presidents, they did nothing, though a presidential
advisory task force during the Ford administration did detail a
proposed procedure.*(231)
Still, progress has been made. Although I have used the future tense
in describing the fact forum, experiments have begun. But before
describing a path to due process, it makes sense to consider some of
the objections.
-
WHY NOT DUE PROCESS?
-
Critics of this idea (at least in its science court version) have
often disagreed with one another. Some have objected that factual
disputes are unimportant, or that they can be smoothed over behind
closed doors; others have objected that factual disputes are too
deep and important for due process to help. Some have warned that
science courts would be dangerous; others have warned that they
would be impotent. These criticisms all have some validity: due
process will be no cure-all. Sometimes it won't be needed, and
sometimes it will be abused. Still, one might equally well reject
penicillin on the grounds that it is sometimes ineffective,
unnecessary, or harmful.
These critics propose no alternatives, and they seldom argue that we
have due process today, or that due process is worthless. We must deal
with complex, technical issues on which millions of lives depend; dare
we leave these issues to secretive committees, sluggish journals,
media battles, and the technical judgment of politicians? If we
distrust experts, should we accept the judgment of secretive
committees appointed in secret, or demand a more open process?
Finally, can we with our present system cope with a global
technology race in nanotechnology and artificial intelligence?
Open, due-process institutions seem vital. By letting all sides
participate, they will harness the energy of conflict to a search
for the facts. By limiting experts to describing the facts, they
will help us cope with technology without surrendering our decisions
to technocrats. Individuals, companies, and elected officials will
keep full control of policy; technical experts will still be able to
recommend policies through other channels.
How can we distinguish facts from values? Karl Popper's standard
seems useful: a statement is factual (whether true or false) if an
experiment or observation could in principle disprove it. To some
people, the idea of examining facts without considering values
suggests the idea of making policy without considering values. This
would be absurd: by their very nature, policy decisions will always
involve both facts and values. Cause and effect are matters of fact,
telling us what is possible. But policy also involves our values,
our motives for action. Without accurate facts, we won't get the
results we seek, but without values- without desires and
preferences- we wouldn't seek anything in the first place. A process
that uncovers facts can help people choose policies that will serve
their values.
Critics have worried that a science court will (in effect) declare
the Earth to be flat, and then ignore an Aristarchus of Samos or a
Magellan when he finds evidence to the contrary. Errors, bias, and
imperfect knowledge will surely cause some memorable mistakes. But
members of a technical panel need not claim a bogus certainty. They
can instead describe our knowledge and outline our ignorance,
sometimes stating that we simply don't know, or that present
evidence gives only a rough idea of the facts. This way, they will
protect their reputations for good judgment. When new evidence
arrives, a question can be reopened; ideas need no protection from
double jeopardy.
If fact forums become popular and respected, they will gain
influence. Their success will then make them harder to abuse: many
competing groups will sponsor them, and a group that abuses the
procedure will tend to gain a bad reputation and be ignored. No single
sponsoring group will be able to obscure the facts about an
important issue, if fact forums gain reliability through redundancy.
No institution will be able to eliminate corruption and error, but
fact forums will be guided, however imperfectly, by an improved
standard for the conduct of public debate; they will have to fall a
long way before becoming worse than the system we have today. The
basic case for fact forums is that (1) due process is the right
approach to try, and (2) we will do better if we try than if we don't.
-
BUILDING DUE PROCESS
-
Anthropologist Margaret Mead was invited to a colloquium on the
science court*(232) to speak against the idea. But when the time came,
she spoke in its favor, remarking that "We need a new institution.
There isn't any doubt about that. The institutions we have are totally
unsatisfactory. In many cases, they are not only unsatisfactory,
they involve a prostitution of science and a prostitution of the
decision-making process." People with no vested interest in the
existing institutions often agree with her evaluation.
If finding the facts about technology really is crucial to our
survival, and if due process really is the key to finding the facts,
then what can we do about it? We needn't begin with perfect
procedures; we can begin with informal attempts to improve on the
procedures we have. We can then evolve better procedures by varying
our methods and selecting those that work best. Due process is a
matter of degree.
Existing institutions could move toward due process*(233) by
modifying some of their rules and traditions. For example,
government agencies could regularly consult opposing sides before
appointing the members of an expert committee. They could guarantee
each side the right to present evidence, examine evidence, and
cross-examine experts. They could open their proceedings to observers.
Each of these steps would strengthen due process, changing Star
Chamber proceedings into institutions more worthy of respect.
The public benefits of due process won't necessarily make it popular
among the groups being asked to change, however. We haven't heard
the thunder of interest groups rushing to test their claims, nor the
cries of joy from committees as they throw open their doors and submit
to the discipline of due process. Nor have we heard reports of
politicians renouncing the use of spurious facts to hide the political
basis of their decisions.
Yet three U.S. presidential candidates did endorse science courts.
The Committee of Scientific Society Presidents, which includes
twenty-eight of the leading scientific societies in the U.S., also
endorsed the idea. The U.S. Department of Energy used a "science
court-like procedure" to evaluate competing fusion-power proposals,
and declared it efficient and useful. Dr. John C. Bailar of the
National Cancer Institute, after failing to make medical organizations
recognize the dangers of X rays and reduce their use in mass
screening, proposed holding a science court on the subject. His
opponents then backed down and changed their policies- apparently, the
mere threat of due process is already saving lives. Nevertheless,
the old ways continue almost unchallenged.
Why is this? In part, because knowledge is power, and hence
jealously guarded.*(234) In part, because powerful groups can
readily imagine how due process would inconvenience them. In part,
because an effort to improve problem-solving methods lacks the drama
of a campaign to fight problems directly; a thousand activists bail
out the ship of state for every one who tries to plug the holes in its
hull.
Governments may yet act to establish science courts, and any steps
they may take toward due process merit support |
