Under what conditions can moral claims be said to be true? Copp's book explores this question, starting from a new cognitivist theory of normative judgement - 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. According to the theory, a moral proposition is true only if a corresponding moral standard is relevantly justified.

At the heart of the book is a theory of the circumstances under which moral standards qualify as justified, the "society-centered theory." Copp 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. The standard-based theory says, then, that corresponding moral propositions may therefore be true.

Offering new perspectives on reason and rational choice, Copp's approach to morality and normativity raises a number of important issues in moral theory, as well as in metaphysics and the philosophy of language.