Fodor and Piatelli-Palmarini have replied to a review of their book What Darwin Got Wrong with a letter which includes this:
Our difficulty with Darwin is very like our difficulty with our stockbroker. He says the way to succeed on the market is to buy low and sell high, and we believe him. But since he won’t tell us how to buy low and sell high, his advice does us no good. Likewise, Darwin thinks that the traits that are selected-for are the ones that cause fitness; but he doesn’t say how the kinds of variables that his theory envisages as selectors could interact with phenotypes in ways that distinguish causes of fitness from their confounds. This problem can’t be solved by just stipulating that the traits that are selected for are the fitness-enhancing traits; that, as one said in the 1960s, isn’t the solution; it’s the problem.
I cannot understand how clever people can get themselves into such a state. This is an argument against everything, as far as I can tell. Darwin isn't advising *how* to buy low and sell high. Otherwise he would be omniscient. He's identifying the mechanism. As is the stockbroker. Here's some news, for the slow of learning; stockbrokers don't know exactly *how*. Otherwise they'd all be multi-billionaires. Sometimes they get it right. The good ones get it right more than others. Nature gets it right because it has no alternative; it's what happens! But Darwin can't pre-figure it. Just because he can't, doesn't invalidate the mechanism, any more than the stockbroker getting it wrong does. Once again, that science doesn't know all the answers, doesn't invalidate it. If it predicted an answer that didn't fit the facts, it would.
This sort of reasoning from professionals baffles me. I wonder how these people get gainful employment.