Lon L. Fuller

Lon Luvois Fuller lived from 1902 to 1978 and was an American legal philosopher best known as a proponent of a secular and procedural form of natural law theory. A professor of law at Harvard Law School for many years, he is noted in American law for his contributions to jurisprudence and the law of contracts. His 1958 debate with the British legal philosopher H. L. A. Hart in the Harvard Law Review, known as the Hart-Fuller debate, was important in framing the modern conflict between legal positivism and natural law theory, and in his widely discussed 1964 book The Morality of Law he argued that all systems of law contain an internal morality imposing on individuals a presumptive obligation of obedience. The legal scholar Robert S. Summers said in 1984 that Fuller was one of the four most important American legal theorists of the preceding hundred years.