Legal theorists commonly employ a distinction between justification defenses and excuse defenses, but there are significant theoretical disagreements about the nature of the distinction as well as about what the distinction entails. This dissertation is concerned with finding the best way to describe the distinction between the moral concepts of justification and excuse that underlie the concepts employed by legal theorists. Chapter 1 begins by examining moral defenses in general, with emphasis on their purpose, nature, function, and epistemology. Chapter 2 (...) critically examines many of the traditional theoretical assumptions made about justification and excuse in the literature with the goal of winnowing them down to an uncontroversial core that can provide the foundation for a fuller, more specific account. Chapter 3 examines the ordinary language meaning of the words "justification" and "excuse" in order to identify any analytic constraints on what a correct theoretical account of justification and excuse may legitimately include. Finally, Chapter 4 offers and defends a reductive theory of justification and excuse which I call "the praise/blame theory." This theory identifies justified acts with those prima facie wrongful acts for which the actor is morally praiseworthy and excused acts with those prima facie wrongful acts for which the actor is merely not to blame. This simple account is consistent with the logical form of moral defenses, requires minimal elaboration on the terms' ordinary language content, avoids the conceptual mistakes that plague more traditional theories, and has the potential help resolve nagging theoretical issues in related fields. (shrink)