Darwin Among the Machines (7 page)

In examining the prospects for artificial intelligence and artificial life Butler faced the same mysteries that permeate these two subjects today. “I first asked myself whether life might not, after all, resolve itself into the complexity of arrangement of an inconceivably intricate mechanism,” he recalled in 1880, retracing the development of his ideas. “If, then, men were not really alive after all, but were only machines of so complicated a make that it was less trouble to us to cut the difficulty and say that that kind of mechanism was ‘being alive,' why should not machines ultimately become as complicated as we are, or at any rate complicated enough to be called living, and to be indeed as living as it was in the nature of anything at all to be? If it was only a case of their becoming more complicated, we were certainly doing our best to make them so.”
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These questions can be distilled into one essential puzzle—the origin of life. “We wanted to know whence came that germ or those germs of life which, if Mr. Darwin was right, were once the world's only inhabitants,” asked Butler. “They could hardly have come hither from some other world; they could not in their wet, cold, slimy state have travelled through the dry ethereal medium which we call space, and yet remained alive. If they travelled slowly, they would die, if fast, they would catch fire.”
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The only viable answer, without recourse to some higher being “at variance with the whole spirit of evolution,” was that life “had grown up, in fact, out of the material substances and forces of the world”—as life might once again be growing up out of the material substances and forces of machines.

As Charles Darwin borrowed from his grandfather, I am now borrowing ideas that developed on family ground. My own father, Freeman J. Dyson, a mathematical physicist better known as one of
the architects of quantum electrodynamics, took a midcareer detour into theoretical biology that resulted in a thin volume titled
Origins of Life
. The essence of my father's hypothesis was that life began not once, but twice. “It is often taken for granted that the origin of life is the same thing as the origin of replication,” he wrote, noting that “it is important here to make a sharp distinction between replication and reproduction. . . . Cells can reproduce but only molecules can replicate. In modern times, reproduction of cells is always accompanied by replication of molecules, but this need not always have been so. . . . Either life began only once, with the functions of replication and metabolism already present in rudimentary form and linked together from the beginning, or life began twice, with two separate kinds of creatures, one kind capable of metabolism without exact replication, the other kind capable of replication without metabolism. . . . The most striking fact which we have learned about life as it now exists is the ubiquity of dual structure, the division of every organism into hardware and software components, into protein and nucleic acid. I consider dual structure to be prima facie evidence of dual origin. If we admit that the spontaneous emergence of protein structure and of nucleic acid structure out of molecular chaos are both unlikely, it is easier to imagine two unlikely events occurring separately over a long period of time.”
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Over a period of twenty years, Dyson developed a toy mathematical model that “allows populations of several thousand molecular units to make the transition from disorder to order with reasonable probability.”
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These self-sustaining—and haphazardly reproducing—autocatalytic systems then provide energy (and information) gradients hospitable to the development of replication, perhaps first of parasites infecting the metabolism of primitive precursors of modern cells. Once metabolism is infected by replication, as the Darwins showed us, natural selection will do the rest.

Natural selection does not
require
replication; statistically approximate reproduction, for simple creatures, is good enough. The difference between replication (producing an exact copy) and reproduction (producing a similar copy) is the basis of a broad generalization: genes
replicate
, but organisms
reproduce
. As organisms became more complicated, they discovered how to
replicate
instructions (genes) that could help them reproduce; looking at it the other way around, as instructions became more complicated, they discovered how to
reproduce
organisms to help
replicate
the genes.

If organisms truly replicated, or reproduced even an approximate likeness of themselves without following a distinct set of inherited instructions, we would have Lamarckian evolution, with acquired
characteristics transmitted to the offspring. According to the dual-origin hypothesis, natural selection may have operated in a purely statistical fashion for millions if not hundreds of millions of years before self-replicating instructions took control. This brings us back to Butler versus Darwin, because during this extended evolutionary prelude Lamarckian, not neo-Darwinian, selection would have been at work. We should think twice before dismissing Lamarck because Lamarckian evolution may have taken our cells the first—and most significant—step toward where we stand today. Genotype and phenotype may have started out synonymous and only later become estranged by the central dogma of molecular biology that allows communication from genotype to phenotype but not the other way. Life, however, arrives at distinctions by increments and rarely erases its steps. Remnants of Lamarckian evolution may be more prevalent, biologically, than we think—not to mention Lamarckian tendencies among machines.

“The experts were uniformly unenthusiastic,” Freeman Dyson commented, describing how his venture into biology was received. “Roughly speaking, the difference of view between me and the community of experts is that the experts believe that RNA came first in the evolution of life whereas I believe that proteins came first. . . . The ‘RNA world' has become an accepted dogma doubted only by a few heretics like me.”
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My father asked three fundamental questions: “Is life one thing or two things? Is there a logical connection between metabolism and replication? Can we imagine metabolic life without replication, or replicative life without metabolism?”
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These same three questions surround the origin(s) of life among machines. Here, too, a dual-origin hypothesis can shift the balance of probabilities in life's favor once the distinction between reproduction and replication is understood. In looking for signs of artificial life, either on the loose or cooked up in the laboratory, however permeable this distinction may prove to be, one should expect to see signs of metabolism without replication and replication without metabolism first. If we look at the world around us, we see a prolific growth of electronic metabolism, populated by virulently replicating code—just as the dual-origin hypothesis predicts.

The same dogma that has pervaded most theories of the origin of life—that life and replication are synonymous and arose simultaneously, however unlikely the event—has clouded the subject of artificial life. The first problem is to define what life, real or artificial, is. A prevailing assumption is that life begins with the genesis of self-replicating organisms, programs, or machines. Self-replication is a
sufficient but by no means necessary condition for the origins or propagation of life. Replicators, when they make an appearance, will rapidly gain the upper hand, but this does not mean that they come first. Nor does it mean that replicators will thereafter keep the field to themselves. Under the neo-Darwinian regime—not so much a consequence of the origins of life as a consequence of the origins of death—replicators will, in the long run, win. But there is no law against changing the rules. Intelligence and technology are bringing Lamarckian mechanisms into play, with results that may leave the slow pace of Darwinian trial and error behind.

“And though steam engines are as the angels in heaven, with respect to matrimony, yet in their reproduction of machinery we seem to catch a glimpse of the extraordinary vicarious arrangement whereby it is not impossible that the reproductive system of the mechanical world will be always carried on,” noted Samuel Butler in 1865.
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Seven years later he was more explicit about the reproductive strategies of machines: “Surely if a machine is able to reproduce another machine systematically, we may say that it has a reproductive system. What is a reproductive system, if it be not a system for reproduction? And how few of the machines are there which have not been produced systematically by other machines? . . . Each one of ourselves has sprung from minute animalcules whose entity was entirely distinct from our own, and which acted after their kind with no thought or heed of what we might think about it. These little creatures are part of our own reproductive system; then why not we part of that of the machines? . . . We are misled by considering any complicated machine as a single thing; in truth it is a city or society, each member of which was bred truly after its kind.”
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In Butler's time the business of replication was conveyed from generation to generation by engineers. The kingdom of machines might be growing and evolving, but to view machines as organisms was premature. “The kingdoms of living matter and of not-living matter are under one system of laws,” declared Butler's adversary Thomas Huxley, “and there is a perfect freedom of exchange and transit from one to the other. But no claim to biological nationality is valid except birth.”
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Samuel Butler died in 1902. The mechanical kingdom continued to proliferate, spawning a cascade of new species while others, such as steam engines, became extinct. With the advent of electronic digital computers the sense of anticipation—and an interest in Butler's prophecies—was renewed. These machines showed signs of intelligence, and intelligence is a sign of life, even skeptics have agreed. But
to ascribe a living intelligence to computers confuses causes with symptoms and was soon shown to be premature.

Computers may turn out to be less important as an end product of technological evolution and more important as catalysts facilitating evolutionary processes through the incubation and propagation of self-replicating filaments of code. As Erasmus Darwin and his Lunar Circle characterized the age that brought mechanical and electromagnetic metabolism to life, so John von Neumann and his circle of engineers and programmers characterized the origins, two centuries later, of self-replicating strings of bits. In 1948, von Neumann delivered his “General and Logical Theory of Automata,” from which my father, in his
Origins of Life
, condensed the essential truths that “metabolism and replication, however intricately they may be linked in the biological world as it now exists, are logically separable. It is logically possible to postulate organisms that are composed of pure hardware and capable of metabolism but incapable of replication. It is also possible to postulate organisms that are composed of pure software and capable of replication but incapable of metabolism.”
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The origins of life as we know it—and life as we are creating it—are to be found in the cross-fertilization between self-sustaining metabolism and self-replicating code. The coalescence of the kingdom of numbers with the kingdom of machines has been incubating for over three hundred years. By the time Erasmus Darwin began experimenting with the effects of electrochemical signals conveyed through his patients' twitching nerves, the essential principles of electromagnetic telecommunications had already been conceived. The results include not only human communications at a distance, and the local replication and preservation of data over time, but human communication
with
machines and, increasingly, communication among machines themselves. To put things in historical perspective, back to Samuel Butler, in New Zealand, in 1863 . . .

The harbor of Port Lyttelton, some seven miles southeast of Christchurch, is formed by the crater of an extinct volcano, surrounded by steep hills. When Samuel Butler arrived in New Zealand in January 1860, communication between the two settlements was either by a rough bridle path overland or around the exposed headlands via sea. The colonists soon connected their two communities via telegraph (the first in New Zealand), thereby conveying notice of arriving vessels, the latest wool prices, and other time-sensitive news. Communication between Christchurch and Lyttelton was no longer delayed by the obstacle of the Port Hills, but by the time consumed by a local echo in the first few feet of the circuit—the
telegraph operator's nerves. The telegraph opened on 1 July 1862 and inspired a letter that appeared in the Canterbury
Press
on 15 September 1863. “Why should I write to the newspapers instead of to the machines themselves, why not summon a monster meeting of machines, place the steam engine in the chair, and hold a council of war?” asked the anonymous “mad correspondent.” “I answer, the time is not yet ripe for this. . . . Our plan is to turn man's besotted enthusiasm to our own advantage, to make him develop us to the utmost, and find himself enslaved unawares.

“My object is to do my humble share towards pointing out what is the ultimatum, the ne plus ultra of perfection in mechanized development,” the writer continued, “even though that end be so far off that only a Darwinian posterity can arrive at it. I therefore venture to suggest that we declare machinery and the general development of the human race to be well and effectually completed when—when—when—Like the woman in white, I had almost committed myself of my secret. Nay, this is telling too much. I must content myself with disclosing something less than the whole. I will give a great step, but not the last. We will say then that a considerable advance has been made in mechanical development, when all men, in all places, without any loss of time, are cognizant through their senses, of all that they desire to be cognizant of in all other places, at a low rate of charge, so that the back country squatter may hear his wool sold in London and deal with the buyer himself—may sit in his own chair in a back country hut and hear the performance of Israel in Ægypt at Exeter Hall—may taste an ice on the Rakaia, which he is paying for and receiving in the Italian opera house Covent garden. Multiply instance
ad libitum
—this is the grand annihilation of time and place which we are all striving for, and which in one small part we have been permitted to see actually realised.”
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