Law and morality — the Hart–Devlin debate

The Hart-Devlin debate concerns whether law may legitimately enforce morality. Devlin argues society has the right to use criminal law to preserve its 'shared morality'—the community of ideas holding society together—just as it may suppress treason. Deviation threatens social disintegration. The standard is the 'reasonable man's' feelings of intolerance, indignation, and disgust. Hart counters with a qualified harm principle: law may prohibit only conduct that (i) harms others, (ii) offends public decency, or (iii) exploits the vulnerable. Mere immorality, however disgusting to the majority, cannot justify criminalisation. The debate's enduring significance lies in framing perennial questions about state coercion: must criminalisation serve harm prevention, or may it enforce communal values?

Shaw v DPP [1962] AC 220: Publisher of prostitutes' directory convicted of conspiracy to corrupt public morals. Viscount Simonds declared courts retain 'residual power to enforce... the moral welfare of the State'. Exemplifies judicial legal moralism Hart attacked.

R v Brown [1994] 1 AC 212: Consensual sadomasochistic acts causing ABH held criminal despite consent. Lord Templeman: 'Society is entitled and bound to protect itself against a cult of violence.' Clearest modern judicial endorsement of Devlin's position.

R (Nicklinson) v Ministry of Justice [2014] UKSC 38: Challenge to blanket ban on assisted suicide. Court deferred to Parliament on clash between autonomy (Hart) and sanctity of life (Devlin). Shows debate's continuing relevance.

Dudgeon v United Kingdom (1981) 4 EHRR 149: ECtHR held criminalising homosexual conduct violated Article 8. Positive moral sentiment insufficient without 'pressing social need'. International vindication of Hart's approach.

Lawrence v Texas 539 US 558 (2003): US Supreme Court struck down sodomy laws. State cannot 'demean [individuals'] existence... by making their private sexual conduct a crime.' American constitutionalisation of Hartian principles.

Courts and legislators apply the framework through sequential analysis. First, identify the justification offered: harm to others, offence, paternalism, or moralism? Second, if harm-based, demand evidence of causation and magnitude—speculation insufficient. Third, if moralistic, scrutinise whose morality and why it justifies coercion. Key triggers include: sexual conduct (Brown—BDSM), end-of-life decisions (Nicklinson—assisted dying), drug policy (Psychoactive Substances Act 2016), and commodification debates (surrogacy, organ sales). Modern approach typically starts with harm principle as baseline, then considers exceptions. Courts increasingly reject pure moralism but accept harm-adjacent concerns (risk of abuse, symbolic effects). Margin of appreciation in ECHR allows limited moral enforcement where 'necessary in democratic society'.

Conflating positive and critical morality: Students cite majority disgust as sufficient justification, missing Hart's point that positive morality (what people believe) must be evaluated by critical morality (what's justified). Ignoring the empirical claim: Devlin makes a causal assertion—moral deviation causes disintegration—requiring evidence students often overlook. Binary thinking: Treating debate as Hart-or-Devlin when most theorists occupy intermediate positions (Feinberg's offence principle, Raz's perfectionism). Missing the positivism connection: Hart's position flows from his legal positivism—law's validity is separate from its moral merit. Forgetting this misses the debate's jurisprudential significance.