In The Concept of Law, H.L.A. Hart suggested that four formal features of morality distinguish it from law: importance, immunity from deliberate change, the nature of moral offences and the form of moral pressure. On closer examination, none of these supposed features clearly distinguishes morality from law, at least in the broad sense of ‘morality’ that Hart adopted. However, a fifth feature of morality mentioned by Hart – namely the role that morality plays in practical reasoning as a source of ultimate standards for assessing human conduct – does illuminate the relationship between law as conceptualised by Hart and morality variously understood. Because morality has this feature, law is always subject to moral assessment, and moral reasons trump legal reasons. It does not follow, however, that law is irrelevant to moral reasoning.
