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H. L. A. Hart

Analytic · Europe · 1907 to 1992

British legal philosopher who held that law is a system of rules whose validity rests on social facts, not on justice.

What it is

H. L. A. Hart (1907 to 1992) was a British philosopher of law. He is best known for a form of legal positivism, the view that what counts as law and what is morally right are separate questions, and for his book The Concept of Law (1961), a hugely influential account of how legal systems are built.

He was born in Harrogate, studied at Oxford, took his degree in 1929 and worked as a barrister. During the Second World War he served in British intelligence. Afterwards he returned to Oxford, first as a philosophy fellow at New College and, in the early 1950s, as Professor of Jurisprudence. Later he became principal of Brasenose College.

The main ideas

  • Law and morality are separable. Hart insisted on the separability of law and morality, a core point of legal positivism. On this view, whether something is law is a different question from whether it is good.
  • Law as a system of rules. In The Concept of Law he described how different kinds of rules combine to form the structure of a legal system.
  • The rule of recognition. He introduced this idea as part of his account of how a legal system is built. It has shaped later discussion of what makes a rule a law.
  • Liberty and the limits of law. In the 1960s he argued, in the line of John Stuart Mill, that the criminal law should not be used simply to enforce morality, and he argued against legal bans on private, consensual homosexual acts between adults.

What it looks like in practice

Imagine a judge who dislikes a statute and thinks it unjust. For Hart, the judge can say both things at once, that the statute is law and that it is bad law. Whether it is law is one question, and whether it is good is a moral one. This is an illustration of the idea, not an example from his writing.

Books and moments

  • The Concept of Law (1961) is his best-known book.
  • Law, Liberty and Morality (1963) argues, in the line of Mill, that the law should not be used simply to enforce morality.
  • The war years. He worked for British intelligence during the Second World War before returning to Oxford.

Questions and criticism

  • Can law and morality really be kept apart? Some ask whether a legal system can be understood without asking what it is for and whether it is just.
  • Where does the rule of recognition come from? Readers can ask what it rests on, and whether officials always agree on it.
  • Should the law enforce morals? His view is clear, but readers can ask where the law's reach over private life should stop.

Close neighbours

The page on Jeremy Bentham covers an earlier English writer on law and society, and the page on Ronald Dworkin covers another twentieth-century writer on law. The page on John Stuart Mill covers the thinker whose harm principle Hart defended.

Written by epchē in our own words, and checked against independent sources on 29 October 2026. The sources are listed below.

Who they connect to

Influenced by

  • Jeremy Bentham · He took up Bentham's view that law and morals are distinct, and defended it in a modern form.

Reacted against by

  • Ronald Dworkin · Dworkin attacked Hart's view that law is only a set of rules, and argued that moral principles are part of law.

Other Analytic thinkers

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