Abstract

The goal of this dissertation is to offer an account of the normativity of morality that is consistent with the commitments of philosophical naturalism. The issue of normativity can be divided into two parts: motivation and authority. In chapter 1 I attempt to explain the motivational efficacy of a moral system by arguing that it is the natural, biological function of the moral system to produce beliefs about norms, the general observance of which is mutually advantageous and to regulate behavior in accordance with those norms. This accounts for motivation, but not authority, which is what the remainder of the dissertation is devoted to. In chapters 2--3 I take up the issue of practical reason in general, and defend an internalist account of reasons for action. In chapter 2 I consider two primary intuitions behind an internalist account of practical reason, motivation and non-alienation, and argue that a version of the non-alienation requirement is defensible. In chapter 3 I defend an identity-based account of practical reason which respects the non-alienation requirement sketched in chapter 2 while still allowing for a reasonable amount of fallibility. Finally, in chapter 4 I argue that the internalist can account for a limited form of ethical rationalism