On the Dividing Line Between Natural Law Theory and Legal Positivism

Abstract

The nature and location of the disagreement(s) between legal positivism and natural law theory has often been unclear, in large part because of the way each approach has been misunderstood by advocates for the other side. Many commentators assume that the two approaches disagree about whether immoral rules can have the status of law, but there is little evidence to support this view. Natural law theorists from Aquinas to Finnis have allowed that immoral rules are law (can have legal status), only that they are not law in its fullest sense (because such laws do not create moral obligations to obey them). The article concludes that the debate between natural law and legal positivism is joined elsewhere: regarding the meta-theoretical question of whether it is possible and valuable to have a morally neutral theory of law. Legal positivists advocate morally neutral theories, while natural law theorists like Finnis expressly or implicitly argue for a pervasively moral-evaluative theory of law, arguing that one can only understand a reason-giving practice like law against the background of what it would mean to give a good (legitimate, moral-obligation-creating) reason for action. A variation of the same argument is that one can only understand law within a (teleological) theory that gives a place for the moral ideal (justice) to which law strives.