Published online by Cambridge University Press: 01 December 1999
Positivism’s Separability Thesis denies that the legality of a norm necessarily depends on its substantive moral merits; as H.L.A. Hart puts it, “[I]t is in no sense a necessary truth that laws reproduce or satisfy certain demands of morality, though in fact they have often done so.”H.L.A. Hart, The Concept Of Law 185–86 (2d ed. 1994) [hereinafter CL]. Accordingly, the Separability Thesis implies it is logically possible for something that constitutes a legal system to exclude moral norms from the criteria that determine whether a standard is legally valid. In such a legal system, it is neither a necessary nor a sufficient condition for a norm N to be legally valid that N be consistent with a set of moral norms.