The concept of law can be defined only as the reality tending toward the idea of law. - Gustav Radbruch

The validity of demonstrably wrong law cannot conceivably be justified. However, any answer to the question of the purpose of law other than by enumerating the manifold partisan views about it has proved impossible— and it is precisely on that impossibility of any natural law, and on that alone, that the validity of positive law may be founded. At this point relativism, so far only the method of our approach, enters our system as a structural element.
Ordering their living together cannot be left to the legal notions of the individuals who live together, since these different human beings will possibly issue contradictory directions. Rather, it must be uniformly governed by a transindividual authority. Since, however, in the relativistic view of reason and science are unable to fulfill that task, will and power must undertake it. If no one is able to determine what is just, somebody must lay down what is to be legal.

Of course it is true that the public benefit, along with justice, is an objective of the law. And of course laws have value in and of themselves, even bad laws: the value, namely, of securing the law against uncertainty.

Positivism, with its principle that ‘a law is a law’, has in fact rendered the German legal profession defenceless against statutes that are arbitrary and criminal. Positivism is, moreover, in and of itself wholly incapable of establishing the validity of statutes. It claims to have proved the validity of a statute simply by showing that the statute had sufficient power behind it to prevail. But while power may indeed serve as a basis for the ‘must’ of compulsion, it never serves as a basis for the ‘ought’ of obligation or for legal validity. Obligation and legal validity must be based, rather, on a value inherent in the statute.