Tuesday, July 25, 2006

The Cambrian Explosion

I don't know much (in detail) about the rapid onset of phyla known as the Cambrian explosion. In particular, I don't how to evaluate either it or irreducible complexity (its main competitor, as far as I can tell) as the smoking gun for biological intelligent design.

After all, I am biased. I believe that:

Cosmological ID : Biological ID as
physics : evolutionary biology

meaning we are comparing a fundamental science making precise, testable predictions (e.g., the precession of Mercury's orbit) to something much more heuristic. Folks, the really big payoff is in cosmology, not biology. In cosmology there is no fuzziness regarding irreducible complexity or specified complexity or explosions of life, there are only cold-hard facts: tweak the cosmological constant, and you get nothing instead of something.

It may be true that biological IDers make too much of the Cambrian explosion. I really cannot say. It is certainly true their evolutionary opponents tend to react by making too little of it. In following the on-line discussions, you'd get the impression that the Cambrian explosion is no-big-deal, not a problem, what's all the fuss about, etc. Even when acknowledging (begrudgingly, it seems to me) that the Cambrian explosion is, at least in a modest sense, "real", evolutionary apologists will, in some cases, make inane rationalizations.

Case in point: über-scientist-without-portfolio P. Z. Myers wrote, regarding the Cambrian explosion:
But another important lesson, and one that creationists like to hide, is that while this was a sudden event in a geological sense, it wasn't actually all that rapid in human terms. The evolution of the canonical Cambrian forms was drawn out over tens of millions of years. (emphasis in original)
This is a rather crude Red Herring argument. Myers is diverting attention from the true issue, that the Cambrian explosion occurred in a geological blink of the eye, to a irrelevancy, that it didn't happen on human time scales, a claim not held by any serious skeptic.

At any rate, that brings me to my main point: it appears that all is not rosy when it comes to an orthodox (scientifically speaking) understanding of the Cambrian explosion. Simon Conway Morris of the University of Cambridge has published an article entitled Darwin's dilemma: the realities of the Cambrian 'explosion'.

(Hat tip: Hugh Ross.)

The abstract of Conway's article acknowledges the controversy and recurrent confusion (among mainstream biologists—not between IDers and the establishment) regarding the Cambrian explosion. The Cambrian explosion is real, and so-far it has defied explanation—although of course Conway sets out to rectify that problem.

You can tell that it is an evolutionary paper, because the abstract ends with the sentence:
Here I propose that despite its step-like function this evolutionary event [the Cambrian explosion] is the inevitable consequence of Earth and biospheric change.
All evolutionary post-dictions, either explicitly or implicitly, have the luxury of boldly proclaiming how what has already happened was inevitable. Evolution is in a class by itself in proving that the past unfolded as Darwin's marionette. They are decidedly less adept at predicting the next act.

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