Ambivalent assimilation

Legal philosophy as a discipline, was, at best, a marginal topic of philosophical inquiry before H. L. A. Hart turned his attention to it. It may be said of Hart that no philosopher after Hart's work in the philosophy of law could ever reasonably regard legal philosophy as marginal again. Before Hart, legal positivism had, of course, its important advocates, but Hart's The Concept of Law showed that its earlier proponents had been wedded either to a command theory of law that was clearly indefensible (Hobbes, Bentham, and Austin) or a conception of norms that was inadequately defended (Kelsen, Hagerstrom, Alf Ross). In the place of the foundational concepts of command or norm, Hart rigorously defended a sociologically informed account of the operation of legal systems (marked by certain indicia of observance and acceptance) and an illuminating distinction between primary and secondary rules that explained important distinctions in law, for example, between the criminal and civil law and the constitutional law establishing the scope and limits of the competence of officials. On this basis, Hart offered an account of law as a subset of social rules, marked by its monopoly of coercive power over a well-defined territory and the finality of its authority over matters involving the scope and limits of such power. Since truth claims about law are made on the basis of ascertaining such rules, determined by observance and acceptance, such claims in law truthfully can be and are made without knowing whether such rules are substantively just according to a philosophically defensible theory of justice. For this reason, Hart argued that legal positivism is the better philosophy of law, since law can be known without knowing its justice, and positivism makes clear the responsibility of independent ethical criticism of law's sometime amorality and immorality. No one after Hart wrote about these matters, would ever think of law in the same way, and the case for legal positivism, as a philosophy of law, had been placed on an altogether sounder philosophical basis.