In many discussions of the nature of law the terms "legal positivism" and "natural law" are assumed to be the names of rival theories. In fact, each of these designations stands for a number of different and logically distinct doctrines, with the unfortunate result that in many disputes between "positivism" and "natural law" the precise point of conflict is unclear and the classification of a legal theorist as a "positivist" may afford very little indication of the nature of his theory. Thus, what is called the imperative theory of law, that is, the view that laws are commands, is usually treated as a central tenet of legal positivism; but although Jeremy Bentham and John Austin held this view, Hans Kelsen (usually regarded as the most uncompromising of modern legal positivists) held neither this view nor its corollary, that international law is not really law but a...