I’ve never put much effort into sorting out the dispute over evolution and intelligent design, partly because it would take too much work and partly because I really don’t understand why, rationally speaking, there’s such an issue. Still, the Cardinal SchÃ¶nborn situation got me thinking a little about claims that science of necessity is “naturalistic”—it can only consider explanations that are a combination of mechanism and randomness—or that whether that’s so or not there is in fact no evidence for design.
The first point looks like pure dogma, or at best a statement of preferred general practice. Like everyone else, scientists consider intelligent design as an explanation for things they see, including experimental data. Every time a scientist asks himself whether someone fudged the figures to get a result he’s looking at the data for evidence of intelligent design. Presumably, if some new super-telescope discovered the ultimate physical configuration of the universe, strings of clouds of clusters of galaxies and assemblages of dark matter and dark energy, and it turned out that the structure was arranged in the form of letters spelling out the English words “Yay God” in the default typeface for Microsoft Word, astronomers would start talking about intelligent (if very odd) design. How much more ambiguous the result could be and still have that effect I don’t know but I suppose things wouldn’t have to get quite so blatant.
As to the second point, it seems that “evidence” includes anything that makes a proposition more likely and contrary propositions less likely. The neo-Darwinian claim seems to be that examples of complex functioning like the eye aren’t evidence for design because neo-Darwinian evolution explains why we have eyes as well as intelligent design does, and does far better at explaining specific features (e.g., similarities and differences with regard to other species living and dead, various oddities and unnecessary complications in function). As a result, the claim is, every piece of evidence for intelligent design is an even stronger piece of evidence for neo-Darwinian evolution.
I suppose the Intelligent Design argument is that in some cases the neo-Darwinian explanation is not persuasive because the function is too complicated or whatever to arise randomly. How that sort of thing could be measured is of course an issue. I’d expect there to be some mathematical way to compute minimum and maximum probabilities based on the age of the earth, the probability of this and that, the number of atoms of carbon close to the surface of the earth, the conditions and processes disclosed by the fossil record, etc. etc. etc. Whether such techniques could ever yield usable results I have no idea. For all I know they already have and specified complexity or information theory or something give good reason to doubt neo-Darwinian theory. Or maybe they don’t and it’s obvious for some reason that they’ll never work. I have no idea and I’m not going to spend the time to find out.
It seems though that the feeling that there must be something to intelligent design often has less to do with the complexities of life’s physical functioning, surprising as they are, than more general considerations. Such issues include the difficulty, apparently much greater than the difficulty of explaining the origin of species, of explaining the origin of life, and the apparently still greater difficulty of explaining the stupefyingly fine balance among universal constants, the properties of matter, the specific features of the earth and other things (all apparently quite arbitrary) required for life to be possible at all. Why wouldn’t such things bear on whether design is one of the things one can reasonably call on in building up an overall picture of the world and its various features? It’s possible they might all be explained e.g.by some super-Darwinian process involving the evolution of successive universes, but that seems quite speculative. As the neo-Darwinians complain in connection with the “God did it” theory, a universal explanation with no details that can’t conceivably be disproved is no explanation at all.
Beyond that, there is another issue that does not seem to fall within the scope of natural science as now understood: the culmination of the evolution of life in mental functioning and thus things like rational knowledge, aesthetic and moral perception, rational purpose and whatnot. We couldn’t get by very well as ghosts, so it seems that all those things depend on our having bodies of the kind we have. Neo-Darwinian theory might perhaps be able to explain intelligence and knowledge as systems of behavior that make one better able to survive, but it seems it cannot explain the experiences of thinking and knowing, which are not the same and so far as I can tell cannot be reduced to overt behavior and thus to issues of survival and reproduction. So it seems our bodies have aspects that seem extraordinarily important, their ability somehow to support the qualia associated with intelligent behavior, including the ability to contemplate truths of reason or morality or maybe even (if you’re religious) the Divine Perfections, that the neo-Darwinian theory doesn’t seem to account for except as random side effects. They are nonetheless the things, humanly speaking, that the world needs to have value and for that value to be rationally comprehended. Does it make sense to think of them as random occurrences—of knowledge as blind, and of rational intention as totally arbitrary and pointless? Shouldn’t we rather be looking for a system of knowledge that makes it possible to make sense of our situation as a whole?