Abstract
All psychological research on morality relies on definitions of morality. Yet the various definitions often go unstated. When unstated definitions diverge, theoretical disagreements become intractable, as theories that purport to explain "morality" actually talk about very different things. This article argues for the importance of defining morality and considers four common ways of doing so: The linguistic, the functionalist, the evaluating, and the normative. Each has encountered difficulties. To surmount those difficulties, I propose a technical, psychological, empirical, and distinctive definition of morality: obligatory concerns with others' welfare, rights, fairness, and justice, as well as the reasoning, judgment, emotions, and actions that spring from those concerns. By articulating workable definitions of morality, psychologists can communicate more clearly across paradigms, separate definitional from empirical disagreements, and jointly advance the field of moral psychology.