  Some moral skeptics argue that Darwinian explanations of the origins and persistence of morals among humans undermine the likelihood that moral beliefs are true and hence undermine the possibility of moral knowledge. These “debunking” arguments are discussed under three headings. In each case we suppose, as Darwin suggested (Darwin 1982 [1871]), that human morality originated and persisted among our ancestors primarily as an adaptation fashioned by natural selection. This supposition is compatible with cultural evolution playing an enormous role in bringing us from proto-morals to modern forms of morality in all their striking variation. The basic thought, however, is that primitive moral inclinations, such as toward helping family and avoiding harm even to strangers, remain with us as prima facie reasons for action, even when contrary moral considerations may override these core inclinations. Thus, even though modern moralities have evolved culturally, they are, on this premise, constructed from certain core adaptations. That thought is well-developed in current accounts of the evolution of morals (see Copp 2008, pp. 187–90, and Campbell 2009, for a summary and references). While it is not beyond criticism (see the entry on Morality and Evolutionary Biology), I will assume this premise, for the sake of argument, without further elaboration. Strikingly, this premise, if granted, is enough to give weight to the three debunking arguments that follow.