There’s a new review of James Shapiro’s book here. The author, Adam Wilkins, is critical of Shapiro’s main thesis, but accepts there’s a growing body of opinion in certain evolutionary disciplines against classic Neodarwinism.
One of his observations is that Shapiro, like others, downplays the role of natural selection to a bit-part player. He quotes and comments thus:
The matter of selection is then virtually ignored until the final section of the book. There we read, as one of nine bullet-points that summarize the core message: The role of selection is to eliminate evolutionary novelties that prove to be non-functional and interfere with adaptive needs. Selection operates as a purifying but not creative force [emphasis added].
I cannot imagine many evolutionary biologists subscribing to that position.
Of course, evolutionary biologists are not the only players here, as he admits elsewhere in the review. But in support of his opposition, one strand of Wilkins argument is the palaeontological:
The arguments from paleontological evidence for the importance of natural selection largely concern the observed long-term trends of morphological change, which are visible in many lineages. It is hard to imagine what else but natural selection could be responsible for such trends, unless one invokes supernatural or mystical forces such as the long-popular but ultimately discredited force of orthogenesis.
This is what attracts my attention here. In the Origin of Species, as I stated in my previous post, Darwin held a deeply perfectionist position on evolution. There is no doubt that he saw evolution as acting towards not merely the change, but the perfection, of species. This follows from his initial analogy with artificial selection, which he makes clear includes not just the selection of desirable features like speed or long ears, but the overall “improvement of the breed” (a phrase much loved in Victorian livestock breeding as well as the Eugenic Movement). The breeder unconsciously selects “the best” even when not considering specific traits, and so there is a trend to increasing “perfection”.
This implies some absolute, if virtual, “goal” for change (perfection) within nature, and also the unstated assumption that, overall, the environment in loco mentis applies a consistent selective pressure towards that same unintentional goal. Such a consistency would seem a necessary condition for Wilkins’ “observed long term trends of morphological change” in the natural world. But just as Darwin’s concept of perfection is now seen as meaningless (when it is no longer competing with special creation or exemplified by artificial selection), so the environment is increasingly obviously found to be an endlessly swirling and eddying combination of a multitude of factors, without any overall direction. Just as even the simplest organisms are found to be well and complexly adapted to their niches.
This is easy to see in iconic examples like Darwin’s finches, or the peppered moth, whose morphological changes come and go with cycles in weather or other reversible factors. Climate warms and cools even century by century, coastlines flood and recede, species arrive and change the ecology radically, or succumb and reverse those changes. Given such a kaleidoscopic shift in ecologies, and therefore in what constitutes “fitness”, the steady progression of morphological trends appears to occur despite natural selection, rather than because of it. Yet Wilkins’ argument is that it is hard to imagine any other cause than natural selection without invoking the supernatural.
Notice, though, how the argumentation process has developed (evolved?) since Darwin. The Origin of Species opposed its argument principally to special creation. The aim, as I’ve argued before, may have been mainly to propose a plausible alternative that could capture the imagination, but the method was to show how natural selection explained the evidence better. One good example of this is Darwin’s take on island fauna: you’d expect a Creator, he said, to place similar island-friendly species wherever such habitats occur. Instead, as on the Galapagos, the flora and fauna resemble an impoverished and adapted version of the nearest mainland species.
150 years on, the adequacy of selection is being questioned by people like Shapiro. The response is not to return to Darwin and say, “Look, the evidence is here,” because the evidence isn’t actually good enough. Instead, the reply is, “What else but selection could explain this, without allowing God a foothold?” So Darwin displaced the then-prevalent theory, creationism (in an older sense than today’s), by an appeal to better evidence; his successors, finding the evidence insufficient, merely dismiss the original theory out of hand.
Natural selection, then, has in Wilkins’ presentation “evolved” so that it still produces directional change, but with no longer any concept of “perfection” to provide that direction. And he’s done so on the mistaken assumption that creationism went extinct at the hands of natural selection, its main predator. Iconoclasts like Shapiro would seem to represent some unexpected immigrant super-predator, like stoats in New Zealand.
And so evolution explains everything…