Philosophers at least since the time of Plato have been searching for an argument that shows that morality is rationally required. The author addresses American Philosophical Association presidential, "From Rationality to Equality", is significantly expanded in this chapter, is one of the few contemporary attempts to provide an argument. In the chapter, the author argues that the conception of morality so justified can be shown to lead to a demand for substantial equality, thereby linking himself to a much larger group of moral and political philosophers, including Ronald Dworkin, Alison Jaggar, Will Kymlicka, Thomas Pogge, and Larry Temkin. The author's justification of morality is based on the claim that the principle of non-question-beggingness, a principle that must be satisfied by good arguments, favors morality over egoism, where morality is understood to be a nonarbitrary compromise between self-interested and altruistic reasons. The chapter also argues that the conception of morality is quite useful because it succeeds in showing the superiority of morality over egoism.