DISCRETION AND LEGAL THEORY
In the last chapter we examined three arguments, each purporting to show that positivism is inconsistent with a rule of recognition containing moral tests for valid law, and that inclusive positivism is therefore incoherent. The Validity Argument was shown to be unsound on the ground that weight and validity are logically compatible properties. The Pedigree Argument was seen to fail because the moral tests for law sanctioned by inclusive positivism are only contingent features of some possible legal systems. The Argument From Function was discredited on a number of grounds, the primary one being that it seriously exaggerates the positivist's concern for certainty and finality in the law, casting his views concerning how law sometimes serves these values into a form he would reject, namely, a normative theory of law.
In this chapter we consider two further arguments which might be offered to show that positivism is inconsistent with moral tests for law, and that inclusive positivism is therefore internally inconsistent. Both arguments appeal to the idea of discretion, a notion which was extremely important in Dworkin's early assault upon positivism.1 The first argument runs as follows.
According to inclusive positivism, the fact that judges and lawyers appeal to principles of political morality as grounds for determinations of law is consistent with legal positivism. But this is wrong. It is an implication of the positivist's theory of legal reasoning that any appeal to moral principles must always be discretionary. It must involve the creation of new law, not the discovery of pre-existing, valid law. So inclusive positivism is internally incoherent after all,____________________