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Tuesday, July 22, 2008

How blind salamanders make nonsense of creationists' claims.

Illustration by Mark Alan Stamaty. Click image to expand

It is extremely seldom that one has the opportunity to think a new thought about a familiar subject, let alone an original thought on a contested subject, so when I had a moment of eureka a few nights ago, my very first instinct was to distrust my very first instinct. To phrase it briefly, I was watching the astonishing TV series Planet Earth (which, by the way, contains photography of the natural world of a sort that redefines the art) and had come to the segment that deals with life underground. The subterranean caverns and rivers of our world are one of the last unexplored frontiers, and the sheer extent of the discoveries, in Mexico and Indonesia particularly, is quite enough to stagger the mind. Various creatures were found doing their thing far away from the light, and as they were caught by the camera, I noticed—in particular of the salamanders—that they had typical faces. In other words, they had mouths and muzzles and eyes arranged in the same way as most animals. Except that the eyes were denoted only by little concavities or indentations. Even as I was grasping the implications of this, the fine voice of Sir David Attenborough was telling me how many millions of years it had taken for these denizens of the underworld to lose the eyes they had once possessed.

If you follow the continuing argument between the advocates of Darwin's natural selection theory and the partisans of creationism or "intelligent design," you will instantly see what I am driving at. The creationists (to give them their proper name and to deny them their annoying annexation of the word intelligent) invariably speak of the eye in hushed tones. How, they demand to know, can such a sophisticated organ have gone through clumsy evolutionary stages in order to reach its current magnificence and versatility? The problem was best phrased by Darwin himself, in his essay "Organs of Extreme Perfection and Complication":

To suppose that the eye, with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest possible degree.

His defenders, such as Michael Shermer in his excellent book Why Darwin Matters, draw upon post-Darwinian scientific advances. They do not rely on what might be loosely called "blind chance":

Evolution also posits that modern organisms should show a variety of structures from simple to complex, reflecting an evolutionary history rather than an instantaneous creation. The human eye, for example, is the result of a long and complex pathway that goes back hundreds of millions of years. Initially a simple eyespot with a handful of light-sensitive cells that provided information to the organism about an important source of the light …

Hold it right there, says Ann Coulter in her ridiculous book Godless: The Church of Liberalism. "The interesting question is not: How did a primitive eye become a complex eye? The interesting question is: How did the 'light-sensitive cells' come to exist in the first place?"

The salamanders of Planet Earth appear to this layman to furnish a possibly devastating answer to that question. Humans are almost programmed to think in terms of progress and of gradual yet upward curves, even when confronted with evidence that the past includes as many great dyings out of species as it does examples of the burgeoning of them. Thus even Shermer subconsciously talks of a "pathway" that implicitly stretches ahead. But what of the creatures who turned around and headed back in the opposite direction, from complex to primitive in point of eyesight, and ended up losing even the eyes they did have?

Whoever benefits from this inquiry, it cannot possibly be Coulter or her patrons at the creationist Discovery Institute. The most they can do is to intone that "the Lord giveth and the Lord taketh away." Whereas the likelihood that the post-ocular blindness of underground salamanders is another aspect of evolution by natural selection seems, when you think about it at all, so overwhelmingly probable as to constitute a near certainty. I wrote to professor Richard Dawkins to ask if I had stumbled on the outlines of a point, and he replied as follows:

Vestigial eyes, for example, are clear evidence that these cave salamanders must have had ancestors who were different from them—had eyes, in this case. That is evolution. Why on earth would God create a salamander with vestiges of eyes? If he wanted to create blind salamanders, why not just create blind salamanders? Why give them dummy eyes that don't work and that look as though they were inherited from sighted ancestors? Maybe your point is a little different from this, in which case I don't think I have seen it written down before.

I recommend for further reading the chapter on eyes and the many different ways in which they are formed that is contained in Dawkins' Climbing Mount Improbable; also "The Blind Cave Fish's Tale" in his Chaucerian collection The Ancestor's Tale. I am not myself able to add anything about the formation of light cells, eyespots, and lenses, but I do think that there is a dialectical usefulness to considering the conventional arguments in reverse, as it were. For example, to the old theistic question, "Why is there something rather than nothing?" we can now counterpose the findings of professor Lawrence Krauss and others, about the foreseeable heat death of the universe, the Hubble "red shift" that shows the universe's rate of explosive expansion actually increasing, and the not-so-far-off collision of our own galaxy with Andromeda, already loomingly visible in the night sky. So, the question can and must be rephrased: "Why will our brief 'something' so soon be replaced with nothing?" It's only once we shake our own innate belief in linear progression and consider the many recessions we have undergone and will undergo that we can grasp the gross stupidity of those who repose their faith in divine providence and godly design.

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