Moral claims not only purport to be true, they also purport to guide our choices. This book presents a new theory of normative judgment, the "standard-based theory," which offers a schematic account of the truth conditions of normative propositions of all kinds, including moral propositions and propositions about reasons. The heart of Copp's approach to moral propositions is a theory of the circumstances under which corresponding moral standards qualify as justified, the "society-centered theory." He argues that because any society needs a social moral code in order to enable its members to live together successfully, and because it would be rational for a society to choose such a code, certain moral codes, and the standards they include, are justified. According to the standard-based theory then, if certain moral standards are indeed justified, corresponding moral propositions may be true. Copp's approach to morality and explaining normativity and the truth conditions of moral claims, raises a number of important issues in moral theory, as well as in metaphysics and the philosophy of language.