ABSTRACT
This chapter explores one of the central enterprises of legal theory: the explanation and justification, in principle, of the law's moral authority. It shows how one influential contemporary rejection of that authority rests on an unwarranted assumption of social consensus. The chapter surveys, partly historically and partly systematically, some main aspects of the predicament of contemporary social theories as they struggle to make do with emaciated conceptions of practical reasonableness. Reflection on structural weakness will bring to light the materials needed to construct a positive case affirming the moral obligation to obey the law. The weakness comes to light when we observe how Joseph Raz's influential denial of the law's moral authority goes along with two ungrudging admissions: that everyone has moral reason to cooperate in securing certain social goals, and that law is instrumental in securing those goals. Western social theory has frequently reverted to some such emaciated conception of practical reasonableness.
