More on Why Pigs Don’t Have Wings

In the LRB, Jerry Fodor responds to his critics:

Jerry Coyne and Philip Kitcher make the usual mistake. In fact, I am not worrying about whether we can tell if ‘polar bears were selected for being white or for matching their environment’. I repeat: I don’t do epistemology. Nor do I deny that we can often focus on different aspects of the causal history underlying an episode of selection. The problem is that it makes no sense at all to speak of the aspect of a causal history that selection focuses on; to say (as it might be) that selection focused on the whiteness of the polar bear rather than its match to the surround. Selection doesn’t focus: it just happens.

Coyne and Kitcher then say that ‘the concept of “selecting for” characteristics is largely a philosopher’s invention.’ I don’t know who invented it, but that can’t be right. If the theory of adaptation fails to explain what phenotypic traits were selected for, it won’t generalise over possible-but-not-actual circumstances; it won’t, for example, tell us whether purple polar bears would have survived in the ecology that supports ours. It will not be ‘news to most knowledgeable people’ that empirical theories are supposed to support relevant counterfactuals. If adaptationism doesn’t, that is news.

Coyne and Kitcher suggest that evo-devo doesn’t purport to be an alternative to adaptationism but rather is ‘consistent with’ natural selection. That’s right but not relevant. Part of my point was that if adaptationism is independently incoherent (as, in fact, I believe it to be) then we’re in want of an alternative. Evo-devo may reasonably be considered a step towards supplying one.