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Revolutionary Evolutionist
For Richard Dawkins, genes are selfish, the watchmaker is blind, and the mystery of life is no mystery - it's digital.
By Michael Schrage
In the cluttered back room of Richard Dawkins's Oxford flat, a
Macintosh morphs through the image of a human skull evolving. Over
and over, the huge prognathic jaw shrivels as the cranial cavity
swells to grotesquely large proportions: tiny brain, monster brain.
"This is what our skulls might look like in thousands of years,"
Dawkins remarks, glancing at the screen, "should we be around that
long." That same trend applied to Dawkins's own skull produces the
image shown on the cover of this magazine.
But even without futuristic morphing, Dawkins's head holds more
provocative ideas than most. Two decades ago, Dawkins presented a
radical evolutionary perspective in a small book called The
Selfish Gene, a disturbingly persuasive essay arguing that living
things are little more than corporal vessels impelled to heed the
primal dictates of selfish genes hellbent on their own replication
and propagation. Much as the English philosopher and novelist Samuel
Butler observed a century ago that a chicken is just a way an egg
makes another egg, Dawkins proposed that we are nothing but
expressions of our selfish genes in the process of making more
selfish genes. Taking that idea even further, Dawkins proposed that
genes themselves are expressions of particularly elegant code
manipulating the world around it to its own reproductive end. He
extended these notions into culture and described ideas as competing,
self-replicating entities he called memes. Dawkins's most recent
book, River Out of Eden (see excerpt),
extends his life's work into a unified evolutionary theory arguing
that all life, at its core, is a process of digital-information
transfer.
These ideas are intriguing, even a little outrageous, but - most
importantly - they have proven astonishingly influential. When a
Dawkins meme smacks into your neurons, your neurons obediently
repattern themselves around it. You might resist their explicit
message, but they are difficult to ignore and impossible to dismiss.
They're quite fit - in the Darwinian sense.
Dawkins's revolutionary evolutionary rhetoric has particularly
inspired researchers of artificial life. Indeed, Dawkins's work has
created new contexts for exploring genetic algorithms and has
sensitized the growing community of artificial-life researchers to
the evolutionary dynamics of their software creations. Much as
Herbert Simon and Marvin Minsky framed the agenda for artificial
intelligence, Richard Dawkins has effectively defined the
evolutionary agendas for artificial life. If you want to understand
the future of natural and synthetic evolution, you have to read
Richard Dawkins.
The morphing skulls are just a taste of Dawkins's designs on
synthetic evolution. Other randomly selected signs of digital
Darwinism are strewn throughout Dawkins's apartment. The seat
cushions for the wooden chairs are immaculately embroidered with
images of color biomorphs - polychromatic representations of progeny
that Dawkins first bred a decade ago with his own home-brewed
artificial life program. So, don't sit on them. They were lovingly
sewn by Lalla Ward - Dawkins's third wife - best known in Britain as
Romana, the comely assistant to the BBC's Dr. Who but perhaps
more proud of her role as Ophelia in a BBC production of
Hamlet. She and Dawkins were introduced at a party by Douglas
Adams, author of the science fiction classic The Hitchhiker's
Guide to the Galaxy. Small
world.
The biomorphs are reminiscent of the musings of D'Arcy Thompson, the
British biologist of natural forms. Completely aware of the innate
ability of computers to replicate data patterns, in 1984 Dawkins
decided to play God and write a simple program to generate treelike
structures on his Apple II. He called them biomorphs - living
structures. He determined the "fitness" of the image and tried to
breed aesthetically charming virtual trees. But the program birthed
much more than stately elms or magnolias. Dawkins described the
excitement of his discovery of synthetic life forms in The Blind
Watchmaker: "When I wrote this program, I never thought that it
would evolve anything more than a variety of treelike shapes. I had
hoped for weeping willows, cedars of Lebanon, Lombardy poplars,
seaweeds, perhaps deer antlers. Nothing in my biologist's intuition,
nothing in my 20 years experience of programming computers, and
nothing in my wildest dreams prepared me for what actually emerged on
screen. I can't remember exactly when in the sequence it first began
to dawn on me that an evolved resemblance to something like an insect
was possible. With a wild surmise, I began to breed, generation after
generation, from whichever child looked most like an insect. My
incredulity grew in parallel with the evolving resemblance.... I
still cannot conceal from you my feeling of exultation as I first
watched these exquisite creatures emerging before my eyes. I
distinctly heard the triumphal opening chords of 'Also Sprach
Zarathustra' (the 2001 theme) in my mind. I couldn't eat, and
that night 'my' insects swarmed behind my eyelids as I tried to
sleep."
Perhaps the most amusing pastiche of synthetic biology to grace the
Dawkins household is the beautifully carved wooden horses. Most are
charming refugees from carnival carousels. A few of the weathered
animals go back to the '50s. Are these simply a charming Dawkins
eccentricity? Not at all. By sheer happenstance, it turns out,
Lally's mother had been collecting them for decades. Now they're
stabled - along with the biomorphs and the simulated skulls - in the
Dawkins home. It all seems quite natural. Really.
In the living room, Dawkins picks up a scrapbook and flips through it
to read from a letter written to him about The Blind
Watchmaker, his pop explanation of natural selection. The letter,
from a New Zealand academic, reads: "One of my most capable students
confessed that she had been reduced to tears by your book. She felt
that any religious belief was now impossible to her, as it had been
logically disproved."
The academic was kind enough to enclose his reply to the student,
which Dawkins reads aloud: "When Lenin traveled through Germany
earlier this century, the Germans permitted him only to travel in a
sealed, locked train - on the condition that he proceeded nonstop
from the one border post to the other. They clearly recognized his
persuasiveness and power of his ideas and their capacity to produce
unhappiness. I respectfully request that you don't lend Dawkins's
book to anybody for the same reasons."
While his tone skids teeteringly close to the brink of smugness,
Dawkins never quite makes it over the edge. His is more the pride of
craft than ego. The letter writer is, of course, absolutely correct.
Dawkins is a dangerous man. Without question, Richard Dawkins is the
most brilliant and compelling propagandist of Darwin today. His
rhetoric inspires even as it provokes. He is a veritable Tom Paine of
evolution, an uncompromising champion of the brute force of natural
selection, ruthlessly dismissive of those who question evolution's
essential truth. Creationists who believe in the divinity of natural
design, of course, might think him more a Goebbels.
But for Dawkins there is nothing left to argue: genes are
selfish; the watchmaker is blind. To say otherwise, he
insists, betrays the truth. Cherished concepts like "free will" and
"spirituality" live in the dark, helical shadows of our genes. He has
roused the ire of England's religious communities by publicly
expressing his view that theology is nothing other than a
pseudo-intellectual grab bag of charming myths. Dawkins is a fiery
evangelist for atheism.
His metaphors, his prose, and his ideas burn with a rational passion
that simultaneously overwhelms and disarms. He is not a scientist
haunted by self-doubt. There are moments in his speech, manner, and
texts when he comes across as completely uncompromising in all of his
firmly held beliefs as any Bishop Wilberforce. Even Harvard's
well-known evolutionist and Darwin booster, Stephen Jay Gould, is a
Darwinian softie by Dawkins's hard
standards.
And Dawkins has been extremely effective in probing the boundaries
between natural evolution and artificial evolution as created in
computers. Indeed, Dawkins's thought suggests that the distinctions
between natural evolution and artificial evolution are
themselves artificial. Evolution is truly transcendental, he
argues: Darwin's dynamics are as universal, as profound, and as
potentially explosive as E=mc2.
This transcendental nature of evolution has bred several new fields
of computer science that have a biological feel to them. One of these
fields is called computational biology; it focuses on using
genetic algorithms and other formulas that imitate genetic
breeding for replicating the effects of evolution in ordinary
computer chips. The stronger form is artificial life; it attempts to
simulate all the essential traits of life - not just evolution -
using silicon (and other substrates) instead of carbon. A-life
researchers believe life is an information process that can be ported
from one matrix to another.
In fact, computational pioneers like Danny Hillis and Stanford
University's John Koza now actively explore software that breeds
other software. Instead of software engineering as the paradigm of
software design, they want to apply Darwin's theories to grow
software that grows solutions. The rise of cheap processors and
parallel architectures creates the ideal digital ecosystems to spawn
software rather than build it. Nature - not rational cognitive
planning - becomes the guiding force for the next generation of
software solutions.
With his skillful articulation of evolutionary issues - combined with
his digital breeding of biomorphs - many researchers consider Dawkins
a conceptual godfather of the artificial life movement. He is as
comfortable with digital media as with the genetics of fruit flies.
He hacks software as readily as he hacks zoology. He wrote his own
word processor for the old Apple II and documented the decision
processes of baby chicks. With his multimedia, multispecies fluency,
Dawkins knows that artificial life has as many insights to offer
biology as biology does artificial life.
A shy man with quick movements, Dawkins circles questions warily -
almost distrustfully. He is cautious and disciplined. Conversation is
not a game. He first pokes at ideas rather than plays with them. He
is almost the caricature of the Oxford don - extraordinarily well
read with a command of language that moves easily between
forcefulness and nuance, with a dry wit that tends toward the droll.
Leon Lederman, the physicist and Nobel laureate, once half-jokingly
remarked that the real goal of physics was to come up with an
equation that could explain the universe but still be small enough to
fit on a T-shirt. In that spirit, Dawkins offered up his own T-shirt
slogan for the ongoing evolution revolution:
Life Results from the
Non-Random Survival of Randomly Varying Replicators.
Expect to
see it on grad student T-shirts everywhere from Oxford and MIT to the
Santa Fe Institute.
Although whimsically done, Dawkins's T-shirt slogan is at the
center of his powerful manifesto. The message nattily packages the
essential insight that makes Dawkins far more than just an
evolutionary propagandist and provocateur. In many ways, what Dawkins
is saying about evolution is as bold for our time as Darwin's tenets
were for his. Dawkins has redefined the fundamental doctrines of
"natural selection" in ways that transform the vocabulary of
evolutionary biology into the new realms of digital media.
What distinguishes Dawkins from most of his evolutionary peers is his
passionate embrace of digital technologies as an appropriate medium
for testing Darwin. Dawkins doesn't have to go to the
Galápagos Islands to test hypotheses about genetic diversity;
he can go to the keyboard. Unlike the life scientists who treat the
personal computer as a calculator, Dawkins intuitively sensed that
the computer should be viewed as a medium for evolution. If genes are
really all about the transmission of information, what better medium
than the computer to simulate how information might
evolve?
Born and raised in East Africa, Dawkins grew up amid one of the most
irresistible bioscapes on Earth. Dawkins came to Oxford in 1959 as an
undergraduate, and eventually came under the spell of Niko Tinbergen,
the eminent Danish biologist. Author of The Study of Instinct
and winner of the Nobel Prize in biology for his pioneering work on
animal behavior, Tinbergen was one of the first of the modern
ethologists (biologists who explore and explain the nature of animal
behavior). What is instinct? Tinbergen would ask. What behavior is
learned? How can we truly know the difference? How does behavior
change? How do animals communicate? How do animals behave differently
in groups than they do as individuals? Why do animals cooperate? How
do they compete?
Ethology, as Tinbergen constantly stressed, was a highly
interdisciplinary biological science, requiring insights into
psychology, physiology, ecology, sociology, taxonomy, and evolution.
Tinbergen focused on the eternal tension between the breadth of
behaviors observed in nature and a scientist's need to reduce these
behaviors to a set of fundamental principles. "My own dominant
recollection of his undergraduate lectures," Dawkins recalls, "was
that I was particularly taken with two phrases of his - behavior
machinery and equipment for survival. When I came to write
my first book, I combined them into the brief phrase survival
machine."
Dawkins developed a special protégé/mentor relationship
with Tinbergen. After a stint at the University of California at
Berkeley, Dawkins returned to his alma mater, where he ultimately
became a fellow at New College (he still teaches there).
Dawkins's dual interest in the nature of machines and the machinery
of nature took place amid the rise of molecular biology. Just a few
years after Francis Crick and James Watson's 1953 discovery of the
double helix, the molecular biologists - not the naturalists,
zoologists, or ethologists - began calling the intellectual shots in
biology. The increased ability to track and explain what the genome
was and what it was doing - classic reductionalist science as opposed
to mere descriptive taxonomies - radicalized the way nature was
observed. Centuries of animal breeding had, of course, created an
explicit awareness of links between genetic endowment and behavior.
The double helix became the new scaffold for erecting theories of
evolution.
For the young Dawkins, the ethology of Tinbergen quickly became the
conceptual lens through which he viewed the world. Behavior, say of
the chicks he studied as a graduate student, was the empirical
observation that Dawkins sought to identify and explain. At the same
time he was observing chicken processing, Dawkins was busy processing
his data with a clunky punch-tape Eliot 803. The machinery metaphor -
the machinery meme - that resonated with and reinforced Tinbergen's
ideas ultimately welded itself to Dawkins's strong notions of the
primacy of the gene. What happens to scientific thinking if the
survival machine is defined by the machinery of the genes?
Amid this primordial soup of new paradigms, Richard Dawkins the
ethologist rapidly mutated into an evolutionary biologist. In 1965,
he hit upon an idea breathtakingly simple to understand but
extraordinarily powerful in its implications. In essence, Dawkins
argued for an ethology of the gene: How do genes communicate? How do
genes behave differently in groups than they do as individuals? Why
do genes cooperate? How do genes compete? The same questions
ethologists ask about chicks and geese and chimpanzees are virtually
identical to the sorts of questions they should be asking about the
genome and its genes.
Others had played with this notion before, but Dawkins made it his
own and aggressively pushed it into the mainstream of science
culture.
As the first true ethologist of the gene, Dawkins de facto became an
evolutionary biologist. How genes behave over time - which ones
dominate, which ones die off, which ones cooperate, which ones
compete, which ones change, which ones remain the same - is the very
definition of an evolution based on the flow of
information.
When Dawkins published The Selfish Gene in 1976, the book
further heated the debate over whether humans were ruled more by
nature or nurture, a debate refueled by the emerging sociobiologists
- notably Harvard biologist Edward O. Wilson in his 1975 book
Sociobiology. By proposing an ethology of the gene, Dawkins
shifted that debate away from the individual animal as the unit of
evolution to the nature, nurture, and behavior of the genes. With
The Selfish Gene, Dawkins offered scientists a conceptual
bridge between the reductionist imperatives of molecular biology and
the taxonomies of zoology, psychology, and sociology. In other words,
the metaphor of the selfish gene not only created an important
context to explain human and animal behavior - it also created a
framework for molecular biologists to examine the organic
interactions of genes. The metaphor scaled from double helices to
human interactions.
But looking at the richness and complexity of life on Earth, Dawkins
freely acknowledged that an ethology of the gene alone was simply not
robust enough to explain evolution. So he applied a Darwinian view of
culture, as well. Dawkins argued for the concept of memes -
ideas that are, to use the felicitous phrase of William Burroughs,
"viruses of the mind." Memes are to cultural inheritance what genes
are to biological heredity. A meme for, say, astrology, could
parasitize a mind just as surely as a hookworm could infest someone's
bowels. Ideas - like genes - could compete and cooperate, mutate and
conserve. They, too, are operated on by natural selection. Human
evolution, Dawkins postulates, is a function of a co-evolution
between genes and memes.
Even that was not enough. Dawkins's intellectual adventure went well
beyond the ethology of genes and memes to explore an even more
radical insight into the nature of evolutionary dynamics. This idea,
too, was astonishingly simple, but it offers a powerful intellectual
framework for a new understanding of life as an information process.
What do genes and memes have in common? Dawkins asked. They are
replicators. Through various but distinct coded systems, they
reproduce; they effect change in their world so they can propagate,
just like viruses in either digital or organic form. Dawkins's most
powerful paradigm is that the unit of evolution is not the individual
- the gene - or the meme, but the replicator.
This was apostasy to Darwinian evolutionists, who took it as dogma
that the dynamics of natural selection cared only for the fitness of
individual organisms and absolutely nothing else. But here was
Dawkins saying that what really counted in "nature tooth and claw"
was the replicating code beneath the organism. Evolution is really
the story of replicators über alles.
Dawkins aggressively evolved this replicator concept. He noted that
discussing the evolution of birds without looking hard at the
evolution of their nests, or at beavers without considering the
evolution of their dams would be prima facie ridiculous. Each is
essential to the survival of the other. It is the combination of bird
and nest, the combination of beaver and dam, that gives a competitive
edge to the animals who build them. Not only does the body of an
organism march to the orders of its genes, but so do the artifacts
the organism builds or uses. In this sense, the egg uses both a
chicken and a nest to make another egg, and so the nest, too, is an
evolutionary extension of the egg.
In biology, the genes in the egg would be called its genotype, while
the physical expression of those genes - the chicken - would be
called its phenotype. Dawkins called this marriage of organism to
artifact The Extended Phenotype - the title of his second
book, published in 1982. Still extending the outer limits of his
replicator idea, Dawkins used this "extended phenotype" construct to
look beyond the individual and artifact to embrace the family of the
organism, its social group, the tools and environments it created.
These are part of the physical "readout" of the genes, the extended
phenotype of the replicating code. The invisible code in genes are
therefore, in a very real sense, manipulating large chunks of the
visible world to their selfish
advantage.
Of course humans - with our massive and complex array of technologies
- have extended our phenotypes more than any other living species.
Just like a bird's nest, a beaver's dam, or a groundhog's intricate
set of underground tunnels, our technologies are now an integral part
of our evolutionary fitness. In light of Dawkins's work, to be a
scientist today and talk about human evolution divorced from
technological evolution no longer makes sense. In the truest and most
fundamental sense, human evolution is now inextricably bound with
technological evolution. Taken to its natural conclusion, Dawkins's
idea suggests that humankind is really co-evolving with its
artifacts; genes that can't cope with that new reality will not
survive into future millennia.
What happens to life - to artificial life - when our unit of
evolutionary observation becomes the replicator? By framing life and
its evolution in the context of replicators and networks of
replicators, Dawkins has forced all of biology to reexamine its
assumptions of the fundamental mechanics of living things. Is
technology just what our genes want, or is it a cultural conspiracy
of our genes and memes? Does human DNA control the technosphere we've
created and live in and around? What does it mean to say that nerve
gas and microprocessors are extensions of selfish genes? These
questions - as much as the genetic underpinning of embryology and
neurophysiology - are the sorts of questions that evolutionists
must now address, posits Dawkins.
So essential is Dawkins's work to redefining life that he might have
fairly titled one of his books On the Origin of Replicators
and expected it to revolutionize science in the most radical fashion
since Darwin. But Dawkins is not the sort to run the risk of
parodying Darwin in this way, because of his respect for the
principles of natural selection. Already, however, this transforming
view is proving to be an extraordinarily robust meme that is rapidly
replicating in human minds.
When Dawkins spoke at the first artificial life conference in Los
Alamos, New Mexico, in 1987, he delivered a paper on "The Evolution
of Evolvability." This essay argues that evolvability is a
trait that can be (and has been) selected for in evolution. The
ability to be genetically responsive to the environment through such
a mechanism as, say, sex, has an enormous impact on one's
evolutionary fitness. Dawkins's paper has become essential reading in
the artificial life community. His multidisciplinary,
interdisciplinary fluency in fields ranging from ethology to software
has made him someone who is closely watched not only by fans of his
popular books but especially by his scientific peers, who range from
Stephen Jay Gould to Marvin Minsky to Roger Penrose.
Now 54, Dawkins has few students of his own. He quietly confesses
that he wouldn't mind becoming Oxford's first professor of synthetic
evolution. (He is seriously on the lookout for an intellectually
adventuresome benefactor to endow such a chair for him.) Dawkins
likes tossing around a semi-serious idea of awarding prize money to
spur innovation and ingenuity in artificial life. (A decade ago, when
his Biomorph program came out, he offered US$1,000 of his own money
to anyone who could find the exact image of a chalice, or Holy Grail,
he had come across in his own explorations. To Dawkins's surprise, a
Caltech software jock claimed the prize within a year.) Dawkins
detailed his new idea in an exchange of e-mail: "My prize would be
for a visually appealing world in which the life-forms have a
visible, and preferably 3-D, morphology on the computer screen. They
must evolve adaptations not just to 'inanimate' factors like the
weather (which would produce essentially predictable, not emergent
evolution) but to other evolving life forms (which is a recipe for
emergent properties)."
Ingenious, and yet there seems to be something vital missing from
Dawkins's venture into multimedia evolution: the hard math. In his
recent autobiography, Edward O. Wilson, every bit as much the
ethologist as Dawkins, describes a lifetime odyssey of intellectual
collaboration. Wilson recognized that he was woefully deficient in
mathematical skills, so he proceeded to forge close ties with a
number of biostatisticians and mathematicians to help him build
accurate models of population biology.
By contrast, Dawkins evinces some remorse but no particular desire to
go beyond his amateur programming and formidable rhetorical skills to
formalize his revolutionary evolutionary ideas into elegant
algorithms that might win the respect of great mathematicians in the
science community. He has had collaborators, none of whom ever really
brought the rigor of quantitative formalism to his work. Dawkins's
métier is metaphor - not
mathematics.
Indeed, in an e-mail exchange, Dawkins is positively testy about
discussing what might be the new math of replicators. He writes:
"Equations are not my language. They are yours, and it was you that
repeatedly brought the conversation back to equations. I'm not saying
that this is not an important way to look at life. Just that it isn't
my way, and I'm not equipped to answer questions on it."
That's not to say Dawkins needs to become expert in cellular automata
or the new math of nonlinear dynamics to continue being a thought
leader in the rapidly evolving field of artificial life. But, just as
fields like physics and chemistry have increasingly become reified
into mathematical representations, it seems inevitable that
artificial life will mutate along similar dimensions.
Perhaps because of this, the lovely color biomorphs and color
mollusks that he has bred on his Macintosh look, umm, a little
anachronistic compared with the new artificial life menageries and
terraria created by artificial-life breeders like Karl Sims and Tom
Ray, who have a superb sense of computationally intensive algorithms.
While Sims, working on a Connection Machine, can breed a digital 3-D
creature that shimmers with lifelike dynamism, Dawkins's own virtual
mollusk looks much like the sort of mollusk you find in a museum.
Dawkins will not be the intellectual adventurer who creates a set of
artificial-life algorithms comparable to, say, Newton's calculus. But
it would be a fitting tribute if, once they are created, those
algorithms carried the name of the man whose memes made their
discovery possible.
A Media Lab Fellow, Michael Schrage is the author of
the newly
published No More Teams! - The Dynamics of Creative Collaboration
(Doubleday Currency).
There
is a river out of Eden, and it flows through time, not space. It is a
river of DNA, a river of information.
An excerpt from Richard Dawkins's new
book.
All organisms that have ever lived - every animal and plant, all
bacteria and all fungi, every creeping thing, and all readers of
these words - can look back at their ancestors and make the following
proud claim: Not a single one of our ancestors died in infancy. They
all reached adulthood, and every single one successfully copulated.
Not a single one of our ancestors was felled by an enemy, or by a
virus, or by a misjudged footstep on a cliff edge, before bringing at
least one child into the world. Thousands of our ancestors'
contemporaries failed in all these respects, but not a single
solitary one of our ancestors failed in any of them. These statements
are blindingly obvious, yet from them much follows: much that is
curious and unexpected, much that explains and much that astonishes.
Since all organisms inherit all their genes from their successful
ancestors, all organisms tend to possess successful genes. They have
what it takes to become ancestors - and that means to survive and
reproduce. This is why organisms tend to inherit genes with a
propensity to build a well-designed machine - a body that actively
works as if it is striving to become an ancestor. That is why birds
are so good at flying, fish so good at swimming, monkeys so good at
climbing, viruses so good at spreading. That is why we love life and
love sex and love children. It is because we all, without a single
exception, inherit all our genes from an unbroken line of successful
ancestors. The world becomes full of organisms that have what it
takes to become ancestors. That, in a sentence, is Darwinism.
There is a river out of Eden, and it flows through time, not space.
It is a river of DNA - a river of information, not a river of bones
and tissues: a river of abstract instructions for building bodies,
not a river of solid bodies themselves. The information passes
through bodies and affects them, but it is not affected by them on
its way
through.
I speak of a river of genes, but I could equally well speak of a band
of good companions marching through geological time. All the genes of
one breeding population are, in the long run, companions of each
other. In the short run, they sit in individual bodies and are
temporarily more intimate companions of the other genes sharing each
body. Genes survive down the ages only if they are good at building
bodies that are good at living and reproducing in the particular way
of life chosen by the species. But there is more to it than this. To
be good at surviving, a gene must be good at working together with
the other genes in the same species - the same river. To survive in
the long run, a gene must be a good companion. It must do well in the
company of, or against the background of, the other genes in the same
river. Genes of another species are in a different river.
The feature that defines a species is that all members of any one
species have the same river of genes flowing through them, and all
the genes in a species have to be prepared to be good companions of
one another. A new species comes into existence when an existing
species divides into two. The river of genes forks in time. From a
gene's point of view, speciation, the origin of new species, is "the
long goodbye." After a brief period of partial separation, the two
rivers go their separate ways forever, or until one or the other
dries extinct into the sand. Secure within the banks of either river,
the water is mixed and remixed by sexual recombination. But water
never leaps its banks to contaminate the other river. After a species
has divided, the two sets of genes are no longer companions. They no
longer meet in the same bodies, and they are no longer required to
get on well.
There are now perhaps 30 million branches to the river of DNA, for
that is an estimate of the number of species on earth. It has also
been estimated that the surviving species constitute about 1 percent
of the species that have ever lived. It would follow that there have
been some 3 billion branches to the river of DNA altogether. Today's
30 million branch rivers are irrevocably separate. Many of them are
destined to wither into nothing, for most species go extinct. If you
follow the 30 million rivers back into the past, you will find that,
one by one, they join up with other rivers. The river of human genes
unites with those leading to other major groups of mammals: rodents;
cats; bats; elephants. After that, we meet the streams leading to
various kinds of reptiles, birds, amphibians, fish, invertebrates.
Francis Crick and James Watson, the unravelers of the molecular
structure of the gene, should be honored for as many centuries as
Aristotle and Plato. Their Nobel Prizes were awarded "in physiology
or medicine," but this is almost trivial. Our whole understanding of
life has been revolutionized as a direct result of the ideas that
those two young men put forward in 1953. Ever since Watson-Crick,
molecular biology has become digital.
Watson and Crick enabled us to see that genes themselves, within
their minute internal structure, are long strings of pure digital
information.
What is more, they are truly digital, in the full and strong sense of
computers and compact disks. The genetic code is not a binary code as
in computers, nor an eight-level code as in some telephone systems,
but a quaternary code, with four symbols. The machine code of the
genes is uncannily computerlike. Apart from differences in jargon,
the pages of a molecular-biology journal might be interchanged with
those of a computer-engineering journal. Among many other
consequences, this digital revolution at the very core of life has
dealt the final, killing blow to vitalism - the belief that living
material is deeply distinct from nonliving material. Up until 1953,
it was still possible to believe that there was something
fundamentally and irreducibly mysterious in living protoplasm. No
longer. Even those philosophers who had been predisposed to a
mechanistic view of life would not have dared hope for such total
fulfillment of their wildest
dreams.
The following science fiction plot is feasible, given a technology
that differs from today's only in being a little speeded up.
Professor Jim Crickson has been kidnapped by an evil foreign power
and forced to work in its biological-warfare labs. To save
civilization, it is vitally important that he should communicate some
top-secret information to the outside world, but all normal channels
of communication are denied him. Except one. The DNA code consists of
64 triplet "codons," enough for a complete upper- and lower-case
English alphabet plus 10 numerals, a space character, and a full
stop. Professor Crickson takes a virulent influenza virus off the
laboratory shelf and engineers into its genome the complete text of
his message to the outside world, in perfectly formed English
sentences. He repeats his message over and over again in the
engineered genome, adding an easily recognizable "flag" sequence -
say, the first 10 prime numbers. He then infects himself with the
virus and sneezes in a room full of people. A wave of flu sweeps the
world, and medical labs in distant lands set to work to sequence its
genome in an attempt to design a vaccine. It soon becomes apparent
that there is a strange repeated pattern in the genome. Alerted by
the prime numbers - which cannot have arisen spontaneously - somebody
tumbles on the idea of deploying code-breaking techniques. From there
it would be short work to read the full English text of Professor
Crickson's message, sneezed around the world.
Our genetic system, which is the universal system of all life on the
planet, is digital to the core. With word-for-word accuracy, you
could encode the whole of the New Testament in those parts of the
human genome which are at present filled with "junk" DNA - that is,
DNA not used, at least in the ordinary way, by the body. Every cell
in your body encodes the equivalent of 715 Mbytes of information,
reeling off digital characters via numerous reading heads working
simultaneously. In every cell, these tapes - the chromosomes -
contain the same information, but the reading heads in different
kinds of cells seek out different parts of the database for their own
specialist purposes. That is why muscle cells are different from
liver cells. There is no spirit-driven life force, no throbbing,
heaving, pullulating, protoplasmic, mystic jelly. Life is just bytes
and bytes and bytes of digital information.
Genes are pure information - information that can be encoded, recoded
and decoded, without any degradation or change of meaning. Pure
information can be copied and, since it is digital information, the
fidelity of the copying can be immense. DNA characters are copied
with an accuracy that rivals anything modern engineers can do. They
are copied down the generations, with just enough occasional errors
to introduce variety. Among this variety, those coded combinations
that become more numerous in the world will obviously and
automatically be the ones that, when decoded and obeyed inside
bodies, make those bodies take active steps to preserve and propagate
those same DNA messages. We - and that means all living things - are
survival machines programmed to propagate the digital database that
did the programming.
With hindsight, it could not have been otherwise. An analog genetic
system could be imagined. But it would resemble a Xerox of a Xerox of
a Xerox. After 800 photocopying "generations," all that's left is a
gray blur. Boosted telephone systems, recopied cassette tapes,
photocopies of photocopies - analog signals are so vulnerable to
cumulative degradation that copying cannot be sustained beyond a
limited number of generations. Genes, on the other hand, can
self-copy for 10 million generations and scarcely degrade at all.
Darwinism works only because - apart from discrete mutations, which
natural selection either weeds out or preserves - the copying process
is perfect.
Only a digital genetic system is capable of sustaining Darwinism over
eons of geological time. Only a digital river of genetic code could
have carried us out of life's Precambrian Eden and into the
present
day.
A Media Lab Fellow, Michael Schrage is the author of the newly published No More Teams! - The Dynamics of Creative Collaboration (Doubleday Currency).;River Out of Eden was published this year by Basic Books.
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