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This review is from: What Darwin Got Wrong (Hardcover)
Last year saw the 150th anniversary of the publication of On the origin of species which was commemorated with the appearance of any number of articles, books, TV programmes etc just about all of which were more or less totally uncritical of the Great Man and his masterpiece. This book coming as it does one year later is refreshing in its dissenting approach.
To a large extent the debate around Darwin's ideas is a hoary one; the boring old story of whether or not his views represent the definitive rejection of the biblical concept of Divine Creation. In this context no distinction is made between the two aspects of Darwinism: its theory of evolution and the mechanism it proposes, natural selection. Neither being mentioned in the Book of Genesis, they are lumped together so that problems with the latter are commonly seen as counting against the former. Foder and Piattelli-Palmarini do not fall into this error; they are not concerned to defend the biblical version from attacks from modern biology - quite the contrary. In other words they fully endorse science's belief in evolution, but they find several grounds for questioning the role and significance of natural selection.
One of their main objections to the concept of natural selection is that, in their opinion, it contains vestiges of purposiveness (or to use their term "intentionality"), for example in the parallel Darwin draws between natural selection and the artificial selection of domestic animals. Here there is a sentient agent, the animal or plant breeder, but there is nothing like that lurking behind nature. I quote from the final paragraphs of the book proper:
[... P]erhaps you would prefer there to be a unified theory - natural selection - of the evolutionary fixation of phenotypes. So be it; but we can claim something that Darwin cannot. There is no ghost in our machine; neither God, nor Mother Nature, nor Selfish Genes, nor the World Spirit, nor free-floating intentions; and there are no phantom breeders either. What breeds the ghosts in Darwinism is its covert appeal to intensional biological explanations, which we hereby propose to do without.
Darwin pointed the direction to a thoroughly naturalistic - indeed thoroughly atheistic - theory of phenotype formation [i.e., speciation]; but he didn't see how to get the whole way there. He killed off God, if you like, but Mother Nature and other pseudo-agents got away scot-free. We think it's now time to get rid of them too. (What Darwin got Wrong, p. 163).
This all might seem very rigorous but what we are left with, on the authors own admission, is no theory of evolution at all; instead of natural selection they would leave us with only natural history, or as they say "one damn thing after another". To these two cognitive scientists this may seem quite OK, but I doubt if most biologists will feel satisfied.
But there seems that the authors have misunderstood where Darwinism sees the roots of innovation. It is not, primarily, in natural selection but in the occurrence of mutations in the genotypes of the organisms that are the well-spring of evolutionary change, and these mutations are chance happenings, whose effects are accumulated over very many generations to give rise to new species. This being the case the main action of natural selection is to retain the (few) beneficial mutations and to dispose of all the deleterious ones. To my mind this does not amount to implicating any ghosts in the evolutionary machine; the question that needs to be asked is does this proposed mechanism offer a reasonable explanation of what Darwin set himself out to explain: the appearance of new species. Implicitly, in the first part of their book, the authors also ask this question. And their answer there is "No it isn't". They point out that many an adaptation is so exquisitely intricate and complex that the chances that they might have come into being as the result of chance mutations, however cumulative, are infinitesimal - mind-bogglingly so. Moreover, the gradualism that this would involve would also be in clear evidence in the fossil record - and it's not! In other words, Darwin was undoubtedly right in embracing the concept of evolution; he was in all probability right too, in positing the existence of natural selection, but he backed a loser in supposing this in combination with chance mutations was the means by which new life-forms come into being.
But does all this mean that we should be as pessimistic as Foder and Piattelli-Palmarini are when it comes to understanding how evolution takes place? I think not. What Darwin could not reasonably have understood, and what modern-day neo-Darwinists ought to understand but do not, is that change is not one-dimensional. There is the kind of change that is necessary for maintaining the stability and durability of systems (in this context, read species) in a variable environment. Such changes, if they originate as genetic mutations, will indeed be the subject of natural selection. But these are not the changes, however numerous they might be, that typically give rise to new species. Here we are talking about higher-order (meta-)change and the mechanisms involved here are only recently coming into view. One such mechanism is so-called horizontal heredity in which large chunks of DNA or RNA are transferred from one species to another, perhaps a totally unrelated one. Evidence is accruing that such transfers, mediated by non-pathogenic viruses, are not only common but seem to be involved in some of the most momentous leaps that have occurred in the history of organic evolution.
These matters are only touched upon in passing in the book under review, but there are other sources to which one can turn for more information. One such is Darwin's Blind Spot. Evolution Beyond Natural Selection by virologist Frank Ryan (2002).