Missing Shades of Grue

"The world is divided into things that look designed (like birds and airliners) and things that don't (rocks and mountains). Things that look designed are divided into those that really are designed (submarines and tin openers) and those that aren't (sharks and hedgehogs). The diagnostic of things that look (or are) designed is that their parts are assembled in ways that are statistically improbable in a functional direction. They do something well: for instance, fly.

Darwinian natural selection can produce an uncanny illusion of design. An engineer would be hard put to decide whether a bird or a plane was the more aerodynamically elegant.

So powerful is the illusion of design, it took humanity until the mid-19th century to realise that it is an illusion. In 1859, Charles Darwin announced one of the greatest ideas ever to occur to a human mind: cumulative evolution by natural selection. Living complexity is indeed orders of magnitude too improbable to have come about by chance. But only if we assume that all the luck has to come in one fell swoop. When cascades of small chance steps accumulate, you can reach prodigious heights of adaptive complexity. That cumulative build-up is evolution. Its guiding force is natural selection.

Every living creature has ancestors, but only a fraction have descendants. All inherit the genes of an unbroken sequence of successful ancestors, none of whom died young and none of whom failed to reproduce. Genes that program embryos to develop into adults who can successfully reproduce automatically survive in the gene pool, at the expense of genes that fail. This is natural selection at the gene level, and we notice its consequences at the organism level. There has to be an ultimate source of new genetic variation, and it is mutation. Copies of newly mutated genes are reshuffled through the gene pool by sexual reproduction, and selection removes them from the pool in a way that is non-random.

What makes for success in the business of life varies from species to species. Some swim, some walk, some fly, some climb, some root themselves into the soil and tilt green solar panels toward the sun. All this diversity stems from successive branchings, starting from a single bacterium-like ancestor, which lived between 3 and 4 billion years ago. Each branching event is called a speciation: a breeding population splits into two, and they go their separately evolving ways. Among sexually reproducing species, speciation is said to have occurred when the two gene pools have separated so far that they can no longer interbreed. Speciation begins by accident. When separation has reached the stage where there is no interbreeding even without a geographical barrier, we have the origin of a new species.

Natural selection is quintessentially non-random, yet it is lamentably often miscalled random. This one mistake underlies much of the sceptical backlash against evolution. Chance cannot explain life. Design is as bad an explanation as chance because it raises bigger questions than it answers. Evolution by natural selection is the only workable theory ever proposed that is capable of explaining life, and it does so brilliantly."

Thanks to Nancy for making me aware of this.

Already under fire for its woeful response to Hurricane Katrina, the federal disaster agency appears to have turned hurricane relief donations into a political payoff - until it was challenged.

All last week, FEMA bureaucrats gave prominent placement on the agency's Web site to Operation Blessing, the Virginia-based charity run by controversial right-wing evangelist and Christian Coalition founder Pat Robertson.

New research on individuals with schizotypal personalities -- people characterized by odd behavior and language but who are not psychotic or schizophrenic -- offers the first neurological evidence that they are more creative than either normal or fully schizophrenic individuals, and rely more heavily on the right sides of their brains than the general population to access their creativity.

Similarly, the claim that something - say the bacterial flagellum - is too complex to have evolved by natural selection is alleged, by a lamentably common but false syllogism, to support the "rival" intelligent design theory by default. This kind of default reasoning leaves completely open the possibility that, if the bacterial flagellum is too complex to have evolved, it might also be too complex to have been created. And indeed, a moment's thought shows that any God capable of creating a bacterial flagellum (to say nothing of a universe) would have to be a far more complex, and therefore statistically improbable, entity than the bacterial flagellum (or universe) itself - even more in need of an explanation than the object he is alleged to have created.

If complex organisms demand an explanation, so does a complex designer. And it's no solution to raise the theologian's plea that God (or the Intelligent Designer) is simply immune to the normal demands of scientific explanation. To do so would be to shoot yourself in the foot. You cannot have it both ways. Either ID belongs in the science classroom, in which case it must submit to the discipline required of a scientific hypothesis. Or it does not, in which case get it out of the science classroom and send it back into the church, where it belongs.

Chimpanzees and people possess almost identical sets of genes, so the genes that have changed down the human lineage should hold the key to what makes people human. (NYT, 09.01.05)