Lon Fuller

Lon Fuller was an American legal philosopher who taught at Harvard Law School for most of his career. He is best known for his 1958 exchange with H. L. A. Hart over the separation of law and morality, and for The Morality of Law, which argues that a legal system must meet certain procedural requirements to count as law at all. His view is often described as a procedural, rather than substantive, natural law theory.

Key ideas

• Law is the enterprise of subjecting human conduct to the governance of rules.
• There is an 'inner morality of law': rules must be general, public, prospective, clear, consistent, possible to obey, relatively stable, and actually applied as announced.
• A system that fails these requirements badly enough does not merely produce bad law; it fails to be a legal system.
• Against Hart, he held that the form of law and its moral standing cannot be cleanly separated.

Major works

• The Case of the Speluncean Explorers (1949)
• Positivism and Fidelity to Law: A Reply to Professor Hart (1958)
• The Morality of Law (1964)

In the conversation

• Discussion Han Feizi’s case for clear law, read in Lahore Hamza Qureshi · 5 replies
• Discussion Fuller’s King Rex, read by someone who spent thirty-one years in the courts Khalid Mahmood Awan · 4 replies
• Discussion Thirty-one years of watching courts decide what is ‘reasonable’, and no degrees of truth in sight Khalid Mahmood Awan · 5 replies