Rachels distinguishes between psychological and moral egoism and attempts to show that neither is justified. In response to the psychological egoist’s claim that people never act unselfishly because they always do what they most want to do, Rachels argues that it is the object of an action (not the subjective desire motivating it) that determines whether that action is selfish. If I want other people to flourish, and I act on that desire, then I am acting unselfishly. The satisfaction I may derive is beside the point.
The ethical egoist argues that even if it is possible to act altruistically, there is no reason why we should. Conceding that no logical refutation of this position is possible—Rachels is unswayed by those who point to its supposed nonuniversalizability—Rachels argues that human welfare is something most of us value for its own sake. No further reasons are necessary for performing actions that help and avoiding actions that hurt others. If the egoist refuses to accept this—that is, if he does not care about the effects of his actions on others—then philosophical argument has reached the limits of what it can accomplish.