The Pure Theory of Law is a theory of positive law, not of a definite legal order, but of the law in general. It is a general theory of law. As such it is the most consistent version of that school of jurisprudence which is called legal positivism because it considers as “law” only positive law and refuses to recognize as law any other normative social order even if, in the usage of language, it is called “law”, as e.g. so-called “natural law”.

Law is—according to the Pure Theory of Law—by its very nature a definite type of norm. As a “norm” the law is the specific meaning of an act of will directed at a definite human behavior. This meaning is: that men ought to behave in a certain way. Hence an essential presupposition of the Pure Theory of Law as a positivistic theory is the recognition of the fundamental difference between the “ought” and the “is”, between norms and assertions. Assertions describe a certain object; they are true or false; norms are not describing, but prescribing; they are neither true nor false; they are valid or non-valid. Hence it is necessary to distinguish as clearly as possible between legal norms established by the legal authority, and assertions of the science of law about legal norms, the sentences by which this science describes its object.