Bill Park says that the idea of meeting old, non-biological civilizations is nicely explored in James P. Hogan's science-fiction novel "Code of the Lifemaker" (Ballantine Books, 1983). The book presents a detailed physical mechanism for robotic evolution. Hogan was a British engineer who left DEC to become a successful science fiction writer. [, 07May98.]

Another source is Stephen Hawking's "Life in the Universe" CD ROM, which proposes that humans will evolve to a mechanical form better suited to space travel. (If nothing more immediate prompts that action, we are likely to migrate when our sun burns out.) Our machines will necessarily mine and refine materials on other planets to manufacture their own replacements, and perhaps they will learn to build ever better machines. Hawking believes that computers will surpass the human mind in interconnection complexity, storage density, and reasoning capability. [Douglas Fraser , 08May98.]

Incidentally, 14May98 is the end of early registration for the Virtual Humans 3 (VH3) conference, 16-17Jun98 in Los Angeles. Sessions include Norm Badler's keynote; authoring tools for virtual humans; standards; synthetic dialog; autonomous humanoids; and a discussion of the digital kidnapping of celebrity personae. . [Mike Bevan , sci.virtual-worlds, 01May98. Bill Park.]

I haven't checked the math -- in particular the combinatorics of equivalent gene orderings -- but physicist Lawrence M. Krauss says there are approximately 1,000 one-of-four base pairs making up a DNA gene, or about 10^600 possible variants. "Now, many of the individual letters in a gene may be irrelevant, but even so, if 99.999999999999999999999999999999999999999999999% of all the possible gene combinations lead to junk genes, the total number of different life-forms which could have appeared on Earth [if each cell produced a new gene sequence each second throughout Earth's history -- 10^47 combinations --] would still be smaller in relation to the number of viable possibilities than one atom is compared to the total number of atoms in the universe! And that's just DNA. We have no idea whether other self-replicating organic, or inorganic, combinations might also be able to exist." ["Beyond Star Trek" (BasicBooks, 1997).]

-- Ken