Any definition of a concept is subject to various criteria for a good definition in the context at hand. Unless we are simply stipulating how we shall be using the word – and even then questions will arise about why we picked that word to use for this stipulation – there will be some, usually implicit, ideas of what makes for a good definition. In addition to trivial ones – such as consistency – there will be a set of problems that the definition will be used to clarify or, if possible, resolve. There will be a set of constraints – weak or strong – on how the word is currently being used. There will be a context – perhaps one of personal ethics or perhaps one of current law – in which the concept finds a place. There will be some conceptual or normative issues that will be used to assess the usefulness or correctness of the definition.

There may be stipulated criteria, e.g., that the concept should not settle some particular normative matter, thereby avoiding what Hart has called the “definitional stop.” For example, if one defines terrorism as the morally illegitimate use of violence on innocent persons then the question of whether terrorism is ever morally legitimate has been settled by the definition. Sometimes, this is not an objection to a definition. If we define “murder” as the wrongful taking of human life then although we cannot raise the question of whether murder is ever right, we can raise the question of whether some killing of a human being is murder. I am going to begin by canvassing a wide variety of definitions of paternalism which may have been developed in quite different contexts for quite different purposes.