Darwin Among the Machines (25 page)

“Given enough time in a sufficiently varied universe,” predicted Nils Barricelli, “the numeric symbioorganisms might be able to improve considerably their technique in the use of evolutionary processes.”
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Cultivating a genetic diversity reserve on the scale of a network implementation of Tierra would be a clever improvement indeed. Not so clever, however, that biology has not had the time to get there first. DNA-based life maintains a global reserve of microorganisms,
able to adapt to changing circumstances at a much faster pace than can more complex organisms—which occasionally suffer from, but ultimately reap the benefits of, new acquisitions made by this public library of genetic code.

In later years, Barricelli continued to apply the perspective gained through his IAS experiments to the puzzle of explaining the origins and early evolution of life. “The first language and the first technology on Earth was not created by humans. It was created by primordial RNA molecules almost 4 billion years ago,” he wrote in 1986. “Is there any possibility that an evolution process with the potentiality of leading to comparable results could be started in the memory of a computing machine and carried on to a stage giving fundamental information on the nature of life?” He endeavored “to obtain as much information as possible about the way in which the genetic language of the living organisms populating our planet (terrestrial life forms) originated and evolved.”
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Barricelli viewed the genetic code “as a language used by primordial ‘collector societies' of t[ransfer]RNA molecules . . . specialized in the collection of amino acids and possibly other molecular objects, as a means to organize the delivery of collected material.” He drew analogies between this language and the languages used by other collector societies, such as social insects, but warned that “trying to use the ant and bee languages as an explanation of the origin of the genetic code would be a gross misunderstanding.”
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Languages are, however, the key to evolving increasingly complex, self-reproducing structures through the cooperation of simpler component parts.

According to Simen Gaure, Nils Barricelli “balanced on a thin line between being truly original and being a crank.” Most cranks turn out to be cranks; a few cranks turn out to be right. “The scientific community needs a couple of Barricellis each century,” added Gaure. As Barricelli's century draws to a close, the distinctions between A-life (represented by strings of electronic bits) and B-life (represented by strings of nucleotides) are being traversed by the first traces of a language that comprehends them both. Does this represent the gene's learning to manipulate the power of the bit, or does it represent the bit's learning to manipulate the power of the gene? As algae and fungi became lichen, the answer will be both. And it is the business of symbiogenesis to bring such coalitions to life.

In the mathematical universe of Kurt Gödel, all of creation—mathematical objects, theorems, concepts, and ideas—can be identified by individual Gödel numbers, establishing a numerical bureaucracy that in Alan Turing's computational universe was extended to
include machines and even organisms, specified by a “state of mind” and a “description number” of some particular (or equivalent) Turing machine. Any Turing machine, and any state of mind, can be encoded, however tediously, as a sequence of Os and Is. Gödel and Turing demonstrated how this universe could be populated by an infinite succession of increasingly powerful languages, thereby proving that we live in a mathematically open universe whose boundaries will never be closed. In the 1930s, no one imagined this formalized, discrete-state universe ever taking actual physical form. “When I was a student, even the topologists regarded mathematical logicians as living in outer space,” recalled Martin Davis, who hand-coded the first theorem-proving program in 1954 at the IAS. “Today . . . one can walk into a shop and ask for a ‘logic probe.'”
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Where logic led, electronics followed. Thanks to Gödel, Turing, and colleagues, the proof was there from the beginning that a digital universe would be an open universe in which mathematical structures of unbounded complexity, intellect, meaning, and even beauty might freely grow. There is no limit, in mathematics or in physics, to how far and how fast Barricelli's numerical symbioorganisms will be able to evolve. “This process will be more expeditious than evolution,” Alan Turing predicted in 1950. “The survival of the fittest is a slow method for measuring advantages. The experimenter, by the exercise of intelligence, should be able to speed it up.”
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T
he latest developments in telecommunications are all-optical data networks. So were the first. The recorded history of high-speed optical data transmission began with the fall of Troy to the Mycenaean army, allegedly in 1184
B.C.
Across the Aegean in Mycenae, as legend has it, Clytaemnestra awaited news from her husband, Agamemnon, absent for ten years in the course of the siege. When Troy was taken, a prearranged signal was relayed overnight to Mycenae, via a line of fire beacons, a distance of some 375 miles, much of it over sea. The tragedy of
Agamemnon
, chronicled by Aeschylus (525–456
B.C.
), opens with Clytaemnestra receiving news of the signal from her watchman while the chorus asks: “And what messenger is there that could arrive with such speed as this?”

Clytaemnestra answers: “Hephaistos [God of fire], sending forth from Ida a bright radiance. And beacon ever sent beacon hither by means of the courier fire: Ida (sent it) to the rock of Hermes in Lemnos; and a huge torch from the island was taken over in the third place by Zeus' peak of Athos; and paying more than what was due, so as to skim the back of the sea . . . transmitting, like a sun, its golden radiance to the look-out of Makistos. And he, not dallying nor heedlessly overcome by sleep, did not neglect his share in the messenger's duty, and afar, over the streams of Euripus, the beacon's light gave the watchers of Messapion the sign of its arrival. They kindled an answering flare and sent the tidings onward, by setting fire to a stack of aged heath. And the vigorous torch, not yet growing dim, leaped, like the shining moon, over the plain of Asopus to the rock of Kithairon and there waked a new relay of the sender fire. And the
far-sent light . . . shot down over the Gorgon-eyed lake and reaching the mountain of the roaming goats. . . . And they with stintless might kindled and sent on a great beard of flame, and it passed beyond the promontory that looks down on the Saronic straits, blazing onward, and shot down when it reached the Arachnaean peak, the watch-post that is neighbour to our city; and then it shot down here to the house of the Atridae, this light, the genuine offspring of its ancestor, the fire from Mount Ida . . . transmitted to me by my husband from Troy.”
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The link between Troy and Mycenae was a one-way, one-time, and one-bit channel, encoded as follows: no signal meant Troy belonged to the Trojans; a visible signal meant Troy belonged to the Greeks. Communications engineers have been improving the bandwidth ever since. Suffering a fate that still afflicts brief messages after three thousand years, Clytaemnestra's message acquired a header—a cumulative listing of gateways that handled the message along the way—longer than the message she received.

A thousand years later, the Greek historian Polybius (ca. 200–118
B.C.
) reported how torch telegraphy had been improved. “The most recent method, devised by Cleoxenus and Democleitus and perfected by myself, is quite definite and capable of dispatching with accuracy every kind of urgent message.” The key was to “take the alphabet and divide it into five parts, each consisting of five letters.” These five divisions of the twenty-four-letter Greek alphabet were inscribed on five tablets. The transmitting station, after signaling and receiving acknowledgment of the beginning of a transmission by raising two torches, “will now raise the first set of torches on the left side indicating which tablet is to be consulted, i.e., one torch if it is the first, two if it is the second, and so on. Next he will raise the second set on the right on the same principle to indicate what letter of the alphabet the receiver should write down.”
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It would be another two thousand years before modern telegraphy instituted a digital coding of the alphabet as concise and unambiguous as this.

In the seventeenth century, the 5-bit ciphers invented by Francis Bacon were elaborated by John Wilkins (1614–1672) in a treatise on cryptography, binary coding, and telecommunications titled
Mercury, or the Secret and Swift messenger: Shewing, How a Man may with Privacy and Speed communicate his Thoughts to a Friend at any distance
, published in 1641. Wilkins, who founded the “Experimentall Philosophicall Clubbe” at Oxford in 1649, married Oliver Cromwell's sister in 1656. He was appointed master of Trinity College, Cambridge, in 1659, first secretary of the Royal Society in 1662, and bishop of Chester in 1668.

Wilkins noted that “two letters of the alphabet, being transposed through five places, will yield thirty-two differences, and so will more
than serve for the foure and twenty letters unto which they may be thus applyed.”
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After showing how this 5-bit binary coding could be conveyed by torch signals and enciphered in numerous ingenious ways, Wilkins described how to transmit alphabetic text as a sequence of binary acoustic signals, anticipating the modern use of binary coding to transmit text-based intelligence, .and to feed the acoustic delay-line storage that gave the stored-program computer industry its start. “It is requisite, that there be two Bels of different notes, or some such other audible and loud sounds, which we may command at pleasure,” wrote Wilkins. “By the various soundes of these (according to the former table) a man may easily espresse any letter and so consequently any sense.”
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Two distinct functions are required of a successful telegraphic code: the encoding of protocols that regulate the process of communication, and the encoding of symbols representing the message to be conveyed. Meaning—in telegraphy as in biology—is encoded hierarchically: first by mapping elementary symbols to some kind of alphabet, then by mapping this alphabet to words, phrases, standard messages, and anything else that can be expressed by brief sequences of code. Higher levels of meaning arise as further layers of interpretation evolve. Protocols, or handshaking, initiate the beginning and end of a transmission and may be used to coordinate error correction and flow control. As Gerard Holzmann and Björn Pehrson observed in their definitive
Early History of Data Networks
, “Some type of protocol has to be established between sender and receiver to deal minimally with the basic problems of synchronization (‘after you,' ‘no, after you!'), visibility (‘repeat please'), and transmission speed (‘not so fast!').”
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Telecommunications systems have appeared, disappeared, and reappeared across the centuries: fire beacons, heliographs, and primitive forms of semaphore based on hanging or waving anything from flags to lanterns in the air. When the Spanish armada entered the English Channel in July 1588, a network of fire beacons raised the alarm, cradling the newborn Thomas Hobbes with fear. The invention of the telescope in the early seventeenth century extended the distance between relay stations and allowed more complex symbols to be distinguished. The feasibility of a “method of discoursing at a Distance, not by Sound, but by Sight” was addressed by Robert Hooke in a lecture, “Shewing a Way how to communicate one's Mind at great Distances,” delivered to the Royal Society on 21 May 1684. Having advanced the optical instruments of his day, Hooke showed that “‘tis possible to convey Intelligence from any one high and eminent Place, to any other that lies in Sight of it, tho' 30 or 40 Miles distant, in as short a Time almost, as a Man can write what he would have sent, and
as suddenly to receive an Answer as he that receives it hath a Mind to return it. . . . Nay, by the Help of three, four, or more such eminent Places, visible to each other . . . ‘tis possible to convey Intelligence, almost in a Moment, to twice, thrice, or more Times that Distance, with as great a Certainty as by Writing.”
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Robert Hooke (1635–1703) was a brilliant but difficult character whose “temper was Melancholy, Mistrustful and Jealous, which more increas'd upon him with his Years.”
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Possessed of “indefatigable Genius,” his creative output was astounding, despite ill humor and ill health. “He is of prodigious inventive head,” reported his contemporary John Aubrey, adding that “now when I have sayd his Inventive faculty is so great, you cannot imagine his Memory to be excellent, for they are like two Bucketts, as one goes up, the other goes downe. He is certainly the greatest Mechanick this day in the world.”
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In 1655, Hooke was appointed assistant to Robert Boyle, executing the construction of Boyle's air pump or pneumatic engine with an ingenuity that descended directly, via Thomas Newcomen's atmospheric engine, to the steam engines of the Industrial Revolution and thence to all internal combustion engines in circulation today. After a meeting of the Royal Society on 15 February 1664 (adjourned to the Crown Tavern until ten o'clock that night), Samuel Pepys noted in his diary that “Above all, Mr. Boyle was at the meeting, and above him Mr. Hooke, who is the most, and promises the least, of any man in the world that ever I saw.”
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