By determining law — so far as it is the subject of a specific science of law — as norm, it is delimited against nature; and science of law against n… - Hans Kelsen

The mark of Platonic philosophy is a radical dualism. The Platonic world is not one of unity; and the abyss which in many ways results from this bifurcation appears in innumerable forms. It is not one, but two worlds, which Plato sees when with the eyes of his soul he envisages a transcendent, spaceless, and timeless realm of the Idea, the thing-in-itself, the true, absolute reality of tranquil being, and when to this transcendent realm he opposes the spacetime sphere of his sensuous perception-a sphere of becoming in motion, which he considers to be only a domain of illusory semblance, a realm which in reality is not-being.

It is called a “pure” theory of law, because it only describes the law and attempts to eliminate from the object of this description everything that is not strictly law: Its aim is to free the science of law from alien elements. This is the methodological basis of the theory.

Law is an order of human behavior. An “order” is a system of rules. Law is not, as it is sometimes said, a rule. It is a set of rules having the kind of unity we understand by a system. It is impossible to grasp the nature of law if we limit our attention to the single isolated rule.