To be sure there are problems. The fossil record is incomplete, but in what we see, we do not see a process of continuous evolutionary development, by constant little changes, as Darwin suggested. Quite large changes seem to happen rather quickly and suddenly, followed by long periods of comparative stability. One wonders, if that is so, how big changes to species, requiring more or less synchronised development in a lot of genetic sites could have occurred by purely random trial and error; the classic random variation and selective retention beloved by Darwinian theorists seems far more appropriate for the gradual accretion of small changes, step by step (which is what we do see in the breeding of fruit flies and the like). And maybe, connected to this point, there is the more general point that many basic evolutionary changes seem to depend on whole complexes of genes being in situ, so to speak, ready for the change, but without contributing anything to the organism’s well-being in advance of the future change.

Intelligent Design

THIS LAST POINT IS the one hammered away at by theorists of Intelligent Design, much to the irritation of the Darwinists, who insist that the examples adduced by their opponents either can be brought within standard evolutionary explanations or will be. As a non-biologist I am not competent to judge on the plausibility of these claims – on either side. However, as a philosopher I can make three critical points about Intelligent Design, two of which are quite independent of the detailed examples, and the third is an entirely general point about the nature of the examples. The first is that in some of its expositions (e.g. Dembski’s), heavy reliance is made on probability, viz, whether the type of complexity found in biological organisms is more or less likely to have occurred through natural selection or through the guiding hand of a designer. The problem here is actually an old one, and is not in any way peculiar to the specific examples adduced by Behe, Dembski and the like. It is that, in the absence of examples of sets of universes with and without designers, we simply have no basis for making the relevant judgements of probability. Universes are not, as C.S.Peirce was fond of saying, as plentiful as blackberries, so we cannot tell whether features of this universe – the only universe – are more or less likely to have emerged randomly or with a intelligent designer.

In reply to this, it might then be said by defenders of the design argument that from what we know of natural processes an ‘irreducibly complex’ system is not likely to have occurred by a blind evolutionary process, and is far more likely to have been produced by a designer as least as intelligent as a human being, which brings me on to the second point. The fact, if it is a fact, that one explanation (blind evolution) is unlikely does not by itself make another explanation (intelligent designer) more likely. And the postulation of an immaterial intelligent designer outside the universe in connexion with things in the universe is something of which we have no experience whatever and is, in addition, beset with all kinds of problems of its own, which was Hume’s point from long ago. So, if their proposal is to have any empirical force,  the proponents of intelligent design will have to tell us rather more about the nature of the designer and his operation than they are actually in a position to do.

And then, thirdly, we are assuming that ‘blind evolution’ cannot do the job required. Not only is this a risky ‘god of the gaps’ manoeuvre, involving a deal of question begging on the part of the intelligent design theorists – for the Darwinists will (and do) vigorously attempt to close the gaps by producing explanations within their framework, showing, for example, that the supposedly independent bits within an ‘irreducibly complex’ biological set-up are not biologically independent at all. Remember that Behe’s favourite image is of the bits of a mousetrap lying around on the ground, with the implicit question as to how such independent entities could ever have been lying around like that without the activity of the mousetrap designer, who then, of course, puts them together. But biological systems are not made up of independent bits in that way; their elements are already living and working together, allowing the systems to take on new functions with quite small changes. Behe would probably say that this is his point: how are we to explain the living, holistic aspects of biological development? But the argument may still go against him here. The organs and tissue of an already existing living organism are not like the components of an inanimate mousetrap, and could, one imagines, take on new functions with comparatively small changes in structure.