Abstract

In various works, Mark Greenberg has positioned himself as an important critic of legal positivism. He has made a transcendental attack on a metaphysical position that some notable legal positivists have held -- namely, that law is ultimately grounded in social facts. He has pressed legal positivism at a point of perceived vulnerability – the failure of such positivists to develop and defend a compelling theory of legal content. Moreover, in his Moral Impact Theory of law, he preserves a necessary connection between legal obligations and good reasons for action that is absent in legal positivism. This last point may seem particularly attractive, even to those with positivist sympathies. One of his arguments against legal positivism relies heavily on what he calls "the bindingness hypothesis"—namely, the claim that it is part of the “nature of law” that it is “supposed to operate” so as to “arrange matters” to “reliably ensure” that its legal obligations are genuinely, all-things-considered, binding. I argue that Greenberg’s defense of the bindingness hypothesis fails. I attack two other defenses he raises for the Moral Impact theory: the assertion that the Moral Impact Theory makes it easy to account for our concern with law, with the implication that legal positivism cannot so easily account for that concern; and the claim that his Moral Impact Theory fits appellate practice better than some views. I show that these the arguments for the Moral Impact Theory are inadequate. In response to Greenberg’s further argument that the Moral Impact Theory rescues the idea of legal obligation as genuine obligation, I argue that the Moral Impact Theory does so at a very steep price – one that is not worth paying.