COEXTENSIVENESS IS A PSEUDOPROBLEM

MM: "Why exactly is coextensiveness issue a problem for Darwinism in particular?"

Ask Jerry Fodor! I think it's either a pseudoproblem or simply the usual empirical task of reducing underdetermination by sorting out, refining and testing rival hypotheses and causal factors with further experiments. (Philosophers for some reason prefer to talk of this instead in terms of "counterfactuals"...)