Pure Theory of Law - Double 'Purity' of Legal Science

Double 'Purity' of Legal Science

Kelsen attempted to reconstruct 'legal science (Rechtswissenschaft)' as a science of 'norms (Normen)', on analogy with Immanuel Kant's conception of natural science. This type of legal science would be 'pure' in two senses.

Firstly, it would be 'pure' in a sense analogous to that in Kant's Metaphysical Foundations of Natural Science. It would set out a priori a 'pure part' of legal science, consisting of a framework of fundamental concepts. Then, in an empirical part of legal science, this framework would be applied to empirical (sociological, historical and so on) material so as to understand that material as 'law'.

The science, in both of its parts, would also be 'pure' in a second sense, in being solely descriptive - excluding from the science any element of evaluation. The core subject matter of legal science, for Kelsen, is legal norms. He defines a 'norm' as 'the meaning of an act of will'. Thus, for Kelsen a norm does not necessarily have any element of generality - hence not all norms are rules. Indeed, as the meaning of an act of will, a norm is not intrinsically rational; departing from Kant both back toward David Hume as well as in the direction of contemporary philosophical positivism, Kelsen denies the existence of practical reason.

Legal science, as Kelsen would like it to be, has to describe a legal norm without either evaluating it or adopting it as an evaluation. This can be done by distinguishing rigorously between the social statement that is the norm itself and the legal-scientific restatement of it that is, or is contained in, a description of the norm. Kelsen terms the norm itself a 'legal norm (Rechtsnorm)' and its descriptive restatement a 'legal proposition (Rechtssatz)'. Thus, when a jurist (legal scientist) states that the law of a certain country contains the norm 'theft is to be punished with imprisonment', this legal proposition is not a comment on whether anybody in that country has a moral or other extra-legal obligation to impose, accept or evade such a penalty. In reading Kelsen, however, one has to bear in mind that, when he refers to a 'norm', he is usually speaking elliptically: he is uttering a legal proposition which stands for a legal norm, in much the same way that a picture of a dog shows the dog but does not bark.

This kind of 'purity' already excludes ideas of natural law, in which description and evaluation are intimately connected. That leaves as the subject matter of legal science only positive law. Kelsen is a 'legal positivist' both in that he excludes evaluation from legal science, through a strict separation of 'is' and 'ought', and in that he considers only positive law to be law. Although he never made much sense of the idea of 'custom', he included all public international law as 'law'.

At the same time, although it is not easy to reconcile with his rejection of practical reason, Kelsen was emphatic that politicians should support and make use of legal science. And legal scientists should assist them, for instance in law reform. Although if, when doing so, they go beyond the role of mere technician and recommend policy-based choices between possible norms, they will no longer be acting as legal scientists. For Kelsen, 'is' and 'ought' occupy separate worlds as a matter of logic, but not in practice. Their logical separation should be incorporated into practice.

Kelsen insisted that, if social scientists wished to deal with law, they would have to take their concept of law from legal science - that is, from the Pure Theory of Law. Kelsen made this point particularly against Max Weber, whose philosophical orientation and legal background were similar to his own. And, indeed, although Weber had said much about what is socially called 'law', he had not developed a clear concept of it himself.