This article presents a theory of reasoning about moral propositions that is based on four fundamental principles. First, no simple criterion picks out propositions about morality from within the larger set of deontic propositions concerning what is permissible and impermissible in social relations, the law, games, and manners. Second, the mechanisms underlying emotions and deontic evaluations are independent and operate in parallel, and so some scenarios elicit emotions prior to moral evaluations, some elicit moral evaluations prior to emotions, and some elicit them at the same time. Third, deontic evaluations depend on inferences, either unconscious intuitions or conscious reasoning. Fourth, human beliefs about what is, and isn’t, moral are neither complete nor consistent. The article marshals the evidence, which includes new studies, corroborating these principles, and discusses the relations between them and other current theories of moral reasoning.