_{RETROSPECTIVE} Barricelli’s Universe _{By George Dyson}

And the evening and the morning were the fifth day…

At 10: 38 p.m. on March 3, 1953, nomena were then reinvestigated in more detail.” Italian-Norwegian mathematical biologist Nils Aall These included symbiosis, incorporation of para-Barricelli (1912-1993) inoculated a 5K digital universe sitic genes into their hosts, and fruitful crossing of with random numbers generated by playing cards gene sequences, which suggested sex. drawn from a shuffled deck. A viral geneticist with a “But,” he reported in August 1953, “in no case has background in physics, Barricelli was granted access the evolution ... led to higher and higher organisms. to the computer at the Institute for Advanced Study Something is missing if one wants to explain the for- (see Make, Volume ⁰⁶, page ¹⁹⁰) to investigate the mation of organs and faculties as complex as those role of symbiosis in the origin of life. of living organisms. No matter how many mutations

“A series of numerical experiments are being we make, the numbers will always remain numbers. made with the aim of verifying the possibility of They will never become living organisms!” an evolution similar to that of living organisms Two essential characteristics of real biology taking place in an artificially created universe,” he were missing: environmental diversity and the announced in the Electronic Computer Project’s interplay between genotype and phenotype that monthly progress report for March 1953. allows Darwinian evolution to advance. “In 1954,

These experiments were hosted by mathematician John von Neumann, who, after the success of “The distinction between an evolution the Manhattan Project at Los Alamos, decided that _{building a digital computer was next.} “_{I am think- experiment performed by numbers} ing about something much more important than in a computer or by nucleotides bombs,” he explained in 1946. “I am thinking about computers.” He was also thinking about self-repro- in a chemical laboratory is a rather ducing automata and the origins of life. subtle one.”

The Institute’s computer was used for meteorological and other scientific problems during the day and ran bomb calculations for “the AEC boys” new experiments were carried out,” he reported, at night. Barricelli took whatever time was left. He “by interchanging the contents of major sectors often operated alone, without engineers in atten- between three universes. The organisms survived dance. Though his log entries recorded the usual and adapted themselves to different environmental problems (“Something is wrong with the building air conditions. One of the universes had particularly conditioner. One of the compressors seems to be unfavorable living conditions, and no organism had stuck and the smell of burning V-belts is in the air.”), been able to survive in that universe previously dur-he had an unusually high success rate, despite the ing the experiment.” To make the leap from geno-running battle between coding and engineering. type to phenotype, he concluded, “we must give (“Code error! Machine not guilty!” and “Dr. Barricelli the genes some material they may organize and claims machine is wrong. Code is right.”) Often he may eventually use, preferably of a kind which has was still at work when the engineers showed up at importance for their existence.” dawn. “Machine worked beautifully. Off!” is his last Barricelli spent much of the remainder of his life entry in the early morning of May 31, 1953. circulating among computer facilities in the United

Barricelli’s universe was designed to appear States and Europe, seeking the CPU cycles his unbounded to any of its inhabitants. “The universe numerical “symbio-organisms” needed to grow. “The was cyclic with 512 generations ... and the code was distinction between an evolution experiment per-written so that various mutation norms could be formed by numbers in a computer or by nucleotides employed in selected regions of the universe,” he in a chemical laboratory is a rather subtle one,” he explained. “Only 5 out of each 100 generations were noted in 1962. He began to develop the functional recorded during reconnaissance. Interesting phe- equivalent of a phenotype by interpreting moves in

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