H. L. A. Hart

H. L. A. Hart was an English legal philosopher whose theory presents law as a union of primary and secondary rules accepted through social practice.

Primary rule: A rule that requires or forbids conduct, imposing duties on those subject to it. Hart treats these duty-imposing rules as law’s basic form.
Rule of change: A secondary rule that gives people or institutions authority to create, modify, or repeal legal rules. Hart identifies it as a remedy for the rigidity of purely customary rules.
John Austin: An English legal thinker who defined law chiefly as a sovereign’s command backed by sanctions. Hart rejects Austin’s command model as too narrow to explain modern legal systems.
Oxford legal philosophy: The tradition of analytic philosophical work on law associated with Oxford University. Hart developed his jurisprudence within Oxford’s analytic philosophy milieu.
Secondary rule: A rule that governs how other rules are recognized, changed, or applied. Hart argues that secondary rules remedy defects in a society of primary rules.
Rule of adjudication: A secondary rule that empowers institutions to determine whether rules were violated and resolve disputes. It addresses uncertainty about who may decide violations of primary rules.
Legal realism: A movement that emphasizes how institutional behavior and practical consequences shape law’s operation. Hart resists reducing legal rules to predictions about what courts will do.
Joseph Raz: A legal philosopher whose work on authority and legal systems developed and criticized aspects of Hart’s positivism. Raz became a prominent successor and interlocutor in debates Hart helped define.
Rule of recognition: A social rule that officials use to identify the criteria of legal validity in a legal system. It supplies the ultimate validity test in Hart’s account.
Open texture: The unavoidable vagueness of general language at the margins of cases not anticipated when rules were made. Hart uses it to explain why judges sometimes exercise discretion in hard cases.

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