The Conceptual Possibility of Moral Criteria of Legal Validity

This chapter gives a positive argument for the claim that the criteria of validity can incorporate moral constraints on the content of law. It thus concludes the defense of the Incorporation Thesis undertaken in the last two chapters. The argument in question constructs a model of an institutional normative system that validates all and only mandatory moral norms in a possible world. The chapter argues that we must do two things to show the conceptual possibility of a legal system with moral criteria of validity. First, we must produce a model of an institutional normative system in a world resembling this one that can plausibly be interpreted as having moral criteria of validity that clearly satisfies every condition plausibly thought to be necessary for the existence of law. Second, to ensure that the model establishes the Incorporation Thesis, it should be incompatible with an exclusivist interpretation.