D. Loeb Moral Realism and the Argument from Disagreement

The argument from disagreement is among the most important that has been directed against moral realism.1 Yet, in recent years it has been widely rejected – so widely, in fact, that even those who are sympathetic with irrealism have often found it unconvincing. One reason for this has to do with the fact that newer, more sophisticated versions of moral realism have recently emerged. Some of these seem more resistant to the argument, in part because of the way they take advantage of philosophical resources not available to their predecessors – resources which have themselves emerged recently in philosophy of science, language, mind, metaphysics, and epistemology. In this paper, I want to take another look at the argument from disagreement. I begin with a brief discussion of J. L. Mackie’s version of the argument, which criticizes the epistemology of moral realism, and especially ofmoral intuitionism. Intuitionism, of course, is out of fashion now, but an examination of the argument in its earlier form will prove useful in our discussion of a more contemporary version of moral realism. Next, I turn my attention to one of the most promising of these, a prominent form of scientific naturalism, and try to explain why the argument still seems so dissatisfying to people on both sides of the debate, why it may be stronger than it has seemed, and what we would have to do in order to see just how strong it is. In the final section of the paper, I consider a less familiar version of the argument – one that focuses on the semantics of moral realism rather than on its epistemology. Here again, I conclude that the argument has more going for it than meets the eye, and that more work is needed to see whether it will ultimately succeed in undermining moral realism.