This Article proposes legal dualism as a novel resolution to one of the central debates in jurisprudence — that between natural law and legal positivism. It holds that the nature of law varies with the purpose for which it is being interpreted. Natural law provides the best account of the law when it serves as a source of moral guidance and legal positivism when it does not.
The Article explores dualism by contrasting it with the defense of legal positivism in Scott Shapiro’s justly renowned book, LEGALITY. Shapiro offers arguably the most sophisticated defense of positivism to date. This Article argues that it does not succeed when the law imposes moral obligations, suggesting a limitation in positivism itself.
Dualism has profound implications. First, it allows us to hold judges accountable for their moral judgments, even when they are merely saying what the law is. Legal positivism can foreclose this possibility.
Second, dualism permits moral argument in support of a particular account of the law, including the theory Shapiro offers, the Planning Theory. Positivism can render unavailable the moral foundation that a theory of law, like the Planning Theory, deserves and that it needs when the law creates moral obligations.
Third, and more generally, dualism holds the potential to move us beyond decades — even centuries — of stalemate between proponents of natural law and positivism. By recognizing that each theory has its place, dualism can advance discussion to the more productive issues of whether the law creates moral obligations and, if so, under what circumstances.