Natural Law versus Legal Positivism

Imagine a building inspector and an architect looking at a newly built house. The inspector asks one question: was it built with a valid permit, by a licensed builder, following the approved procedure? If yes, it is a lawful building, whatever its design. The architect asks a different question: is it a good building, safe, humane and fit to live in? The positivist is the inspector; the natural lawyer is the architect who says that a structure so unsafe that it must fall down is not really a house at all. The quarrel is about which question decides whether something is law. Note 54 set out the definitions and the history; this note covers the modern debate from Hart's 1958 article onwards.

Figure: Natural law builds a bridge between law and morality; legal positivism keeps a gap between them. The dividing question is the separation thesis

1. The Dividing Question: the Separation Thesis

The separation thesis is the positivist claim that there is no necessary connection between law and morality: whether a rule is legally valid depends on its sources (who made it and how), not on its merits. The positivist does not say immoral laws must be obeyed, only that they are still laws; the natural lawyer denies that they carry the full name and authority of law. The dispute is about the concept of law.

2. Hart's Five Meanings of Positivism

In 'Positivism and the Separation of Law and Morals' (Harvard Law Review, 1958), Hart pointed out that the word 'positivism' was used for at least five different claims, which critics lumped together.

Hart's point was that these claims are logically independent, so that attacking one does not refute the others. He himself rejected the command theory (the first), which he dismantled in The Concept of Law (1961), and he rejected the closed logical system (the fourth), insisting on the open texture of rules. His positivism rested mainly on the second and third claims: the separation of law and morals, and conceptual analysis. He left the fifth, a question of moral philosophy, open.

3. The Hart-Fuller Debate

The debate is treated in full in Note 65; here only its structure is needed. Hart's 1958 article defended the separation of law and morals and attacked Radbruch's post-war turn. Fuller replied in the same volume of the Harvard Law Review ('Positivism and Fidelity to Law'), arguing that law has an inner morality, later set out in The Morality of Law (1964).

A regime that fails totally in any of these, said Fuller, does not merely make bad law; it does not make law at all. Hart's reply (in his 1965 review of Fuller's book) was the poisoner objection: these are principles of efficacy, not morality. Poisoning also has its principles of good craftsmanship (avoid poisons that cause vomiting), but no one calls them the inner morality of poisoning. A wicked regime could follow all eight principles and remain wicked. Indian law echoes Fuller in practice: Harla v State of Rajasthan (1951) held that an unpublished law does not bind, and Shreya Singhal (2015) struck down Section 66A of the IT Act for vagueness.

The grudge informer case

In 1944 a German woman, wishing to be rid of her husband, reported to the authorities remarks he had made against Hitler while home on leave. Under Nazi statutes he was sentenced to death, though not executed, and sent to the front. In 1949 a West German court convicted the wife of unlawfully depriving him of liberty, on the ground (as reported and discussed by Hart) that the Nazi statutes were contrary to the sound conscience and sense of justice of all decent people. Hart argued that it would have been more honest to pass an openly retrospective law and punish her, admitting that this sacrificed one value (non-retroactivity) to another, rather than pretend the Nazi statutes were never law. Fuller argued that the Nazi order had so abandoned the inner morality of law that its courts could treat those statutes as void.

4. Two Bridges Between the Camps

5. After Hart: Inclusive and Exclusive Positivism

Dworkin's attack on positivism (Note 19) argued that judges rely on moral principles that no rule of recognition could identify by pedigree. Positivists responded in two ways.

Inclusive (soft) positivism accepts that morality may be part of the test of legal validity, if and because a particular legal system's rule of recognition makes it so. A constitution that invalidates 'unreasonable' laws, for example, makes a moral test into a legal one. Hart adopted this position in his Postscript, published posthumously in 1994 with the second edition of The Concept of Law, calling it soft positivism. W.J. Waluchow (Inclusive Legal Positivism, 1994) and Jules Coleman developed it.

Exclusive positivism, led by Joseph Raz, holds that the existence and content of law must be identifiable from social sources alone, without moral argument (the sources thesis). Raz grounds this in law's claim to authority: an authority's directives are meant to replace the subject's own weighing of reasons, which is impossible if identifying them requires the very moral reasoning they are meant to replace. When a constitution refers to morality, the exclusive positivist says, it directs judges to go beyond the law and make new law.

6. The Natural Law Response: Finnis and Dworkin

John Finnis (Natural Law and Natural Rights, 1980) restated natural law in a way that largely sidesteps the old quarrel. He grounds law in the basic goods of human flourishing (Note 54) and uses the idea of the central case: a just law made for the common good is law in the focal sense; an unjust law is law only in a secondary, watered-down sense. Finnis reads lex iniusta non est lex not as a denial of legal validity but as a claim that such a law lacks the moral authority that the central case of law has. Dworkin, neither natural lawyer nor positivist, offered a third way: law includes the principles that give the best moral justification of the institutional record, so moral reasoning enters into identifying what the law is (law as integrity; Note 19).

7. The Positions Compared

8. The Debate in Indian Constitutional Law

India has a written Constitution full of moral terms (equality, liberty, dignity, reasonableness), which makes much of its law look inclusive-positivist. Yet the Supreme Court has also relied on standards not written in any text.

9. Evaluation

The modern debate has narrowed. Hart concedes a minimum content of natural law and accepts that a legal system may make morality a test of validity; Finnis concedes that unjust laws may be legally valid in a technical sense. Positivism's strength is clarity: it lets us call a rule law and still condemn it. Natural law's strength is fidelity to purpose: law is an institution for the common good, not organised force. Indian constitutional law, with its basic structure and constitutional morality, shows both insights at work.

10. Frequently Asked Questions

Q. Does the positivist say unjust laws must be obeyed?
A. No. The positivist says only that an unjust law is still law. Whether it should be obeyed is a separate moral question, and Hart argued that keeping the two questions apart makes moral resistance clearer, not weaker.

Q. What is the difference between inclusive and exclusive positivism?
A. Inclusive positivism holds that moral criteria can be part of the test of legal validity if the rule of recognition includes them (Hart's Postscript, Waluchow, Coleman). Exclusive positivism holds that law must be identifiable from social sources alone (Raz).

Q. Is Dworkin a natural lawyer?
A. Not in the classical sense. He rejects positivism's claim that law is identified by pedigree alone, but he does not say that unjust laws are void. His law as integrity is usually treated as a third way (Note 19).

See also: Note 54 (positive law and natural law: definitions and history), Note 9 (natural law school), Note 11 (analytical positivism), Note 19 (Dworkin), Note 64 (Hart versus Dworkin), Note 65 (Hart versus Fuller).