Abstract

One of the reasons why philosophers disagree about morals is that they have different theories about those concepts and features of the world which play essential roles in morality. I discuss the cases of two philosophers whose differences are a single concept, that of reason, lead, as I argue, to profound differences in moral theory, metaethics and moral psychology. ;Peters and Allamah are committed to reason and insist that they are giving a rational account of morals. Peters' theory leads him to see morality and moral judgments as products of reason. Believing that the social dimension of reason is dominant, he argues that it is public and co-operative. This led him to claim that a rational moral theory must not be egocentrist. He rejects the view that goodness is a personal matter, since morality emerges from reason, and objectivity and universality are requirements of reason. His theory of reason is responsible for his view that moral judgments are autonomous, objective, and practical. ;Allamah's view of reason confuses a kind of Humean theory and an 'innativist theory', according to which 'virtue is nothing but conformity to reason'. The former is the basis of his moral theory. Allamah's definition of the term 'good' and the state of goodness as an attributive characteristic of actions, and his belief that moral judgments are autonomous and practical but not objective are outcomes of his Humean theory. ;Since both moral theories are determined by their theories of reason both can be seen as rational theories. Now Allamah's view of reason led him to adopt an ethical egoism. But it has widely been accepted that rationality requires universality. Therefore, in the final section I have defended Allamah's ethical egoism as rational