Can evolutionary theory provide evidence against psychological hedonism?

Sober and Wilson (1998) argue (I) that neither psychological evidence nor p hilosophical arguments provide grounds for rejecting psychological hedonism , but (2) evolution by natural selection is unlikely to have led to such a single source of motivation. In order to turn their piecemeal discussion of (1) into a serious argument, Sober and Wilson need a general procedure for mapping alternative accounts of motivation into egoistic hedonistic accoun ts. That is the only way to demonstrate that there will always be an availa ble hedonistic account no matter what the psychological Evidence. But such a general procedure, if available, must block their argument for (2). So, t he more persuasive the case for (1), the less persuasive the case for (2).