Ofterdingen and Kropotkin

The real issue is the biological plausibility of pluralism about motives; it's whether biology entails that, in some sense or other, there is only one goal that we ever pursue. One can imagine selection pressures so intense that no trait survives unless it conduces to reproductive success: but is there any reason at all to suppose that those were the conditions under which we evolved? To the contrary, as far as anybody knows, it looks like we've been singing for fun and dancing for fun and painting for fun and gossiping for fun and copulating for fun right from the start there isn't, to my knowledge, the slightest shred of evidence to the contrary. It's not, in short, part of the "scientific world-view" that only mental traits that favoured reproductive success would have survived in the ancestral environment.
Jerry Fodor, TLS, July 29 2005, p.5