Legal positivism is a modern intellectual tradition in the philosophy of law and jurisprudence that holds that law is a set of rules created by human beings who prescribe certain procedures for its enactment. This contrasts with natural law theory, which has ancient roots and holds that inherent moral principles provide a basis for the law, and that an immoral law is not a true law. Legal positivists oppose this view, maintaining that the validity of a law is determined by social facts such as enactment by a recognized authority following accepted procedures, rather than from any moral criterion.
Legal positivism was developed largely during the 18th and 19th centuries by legal philosophers such as Jeremy Bentham and John Austin. Thomas Hobbes first explained law as anything commanded by the sovereign. Early positivists Bentham and John Austin developed this idea, with the validity of the law deriving from society's recognition of the sovereign's authority to declare law and enforce it. In the Germanic tradition, Hans Kelsen went a step further, divorcing law not only from morals, as the early positivists did, but also from facts, introducing instead the idea of a "norm" as something that "ought to be" in contrast to a fact, that merely "is", and imputing "law" to a legal norm based on the authority of another norm, where the ultimate authority resides not in the sovereign, but in a "basic norm". The most prominent legal positivists of the 20th century included Kelsen, H. L. A. Hart, and Joseph Raz.