Magazine article Skeptic (Altadena, CA)

Predicting Evolution: How Likely Is It That Human-Level Intelligence Will Evolve Again?

Magazine article Skeptic (Altadena, CA)

Predicting Evolution: How Likely Is It That Human-Level Intelligence Will Evolve Again?

Article excerpt

"The universe was not pregnant with life nor the biosphere with man. Our number came up in the Monte Carlo game."

--Jacques Monod Chance and Necessity, 1971.

IF YOU ARE EVEN VAGUELY FAMILIAR WITH science fiction, especially in film, you know that almost all the alien beings are portrayed as humanoid in form and approximately humanoid in intelligence. In the classic 1951 film The Day the Earth Stood Still, the alien Klaatu was humanoid in every detail including his internal organs. This fixation on the humanoid form is at least superficially a function of limited costume budgets for films and television shows, but a deeper reason can be found in limited imagination and the restraints of our progressionist bias that evolution is directional toward something like big brained primates.

The historical antecedents for this bias come to us through the pre-Darwinian view of the scala naturae and the Great Chain of Being, which illustrated a natural evolutionary progression of forms from simple to complex, with humans and human intelligence (of course) being the natural terminus. Many laypeople and science fiction fans continue in this progressionist mode, unaware that this bias is essentially unfounded and rejected by most modern evolutionary biologists. Darwin's work undermined any foundation for progressive thinking by showing that evolution works mainly through the process of natural selection, and all that natural selection can do is to shape populations to be adaptively successful in their local environments. That success is measured only to the extent that organisms have the ability to survive and achieve genetic fitness; that is, the survival of copies of their genes in the next generation--and nothing more. There is no known evolutionary mechanism that works in a progressionist fashion to select consistently in any line for more complex and intelligent beings, let alone beings possessing a humanoid body form.

There simply is no evidence for long-range teleological trends or directions in evolutionary change that would support the idea that evolution tends toward complexity, intelligence, or humanoid morphology. One of Stephen Jay Gould's central themes in his many eloquent writings was his continued emphasis on this important point. As he put it: "We are glorious accidents of an unpredictable process with no drive to complexity." (1) An earlier evolutionist, the great George Gaylord Simpson, wrote in his classic book This View of Life. "The assumption, so freely made by astronomers, physicists, and some biochemists, that once life gets started anywhere, humanoids will eventually and inevitably appear is plainly false." (2)

Still, the progressionist model prevails for many, even among some in the scientific community. A relatively recent entry in this mode comes from the paleontologist Simon Conway Morris, one of the world's leading experts on the Burgess Shale fossils, among the oldest animal fossils ever found. He argues in his 2003 book, Life's Solution: Inevitable Humans in a Lonely Universe, that creatures with approximately human-level intelligence were bound to appear in the evolution of life on Earth--and elsewhere. (3) He bases much of his argument on the concept of convergent evolution, which on this planet has indeed resulted in several cases of multiple appearances of "nearly" identical adaptations. In terms of human intelligence, he seems to suggest that because dolphins, elephants, and a few other animals have achieved large brains, relatively high intelligence, and complex social behavior, human-level intelligence is therefore a probable outcome of the evolutionary process.

This is not an especially convincing argument unless one holds to the progressionist view of evolution. Does Morris actually believe that eventually dolphins and elephants will achieve the level of consciousness and intelligence that humans now possess? Both elephants and dolphins evolved large brains and complex social behavior long before humans did, and yet they have obviously not come up with anything approaching the major hallmarks of human-level intelligence, such as writing. …

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