Abstract

- Peter Railton1 Railton's remark is accurate; contemporary philosophers almost invariably suppose that morality is more vulnerable than empirical science to scepticism. Yet David Hume apparently embraces an inversion of this twentieth century orthodoxy.2 In book I of the Treatise, he claims that the understanding, when it reflects upon itself, "entirely subverts itself" (T 1. 4.7.7; SBN 267) while, in contrast, in book III he claims that our moral faculty, when reflecting upon itself, acquires "new force" (T 3.3.6.3; SBN 619). Such passages suggest Hume's view is that morality's claims on us are justified, whereas the understanding's claims are not -- that scepticism about empirical science, but not morality, is irresistible. However, this interpretation does not accurately reflect Hume's position. Indeed, any interpretation which has Hume concluding that the understanding's claims on us are not justified faces an obvious worry - it makes nonsense of the rest of his naturalistic project, including, but not limited to, his description and justification of our moral faculty. For in defending his account of our moral faculty and, perhaps more clearly, in arguing against those who believe in miracles, Hume inescapably presupposes that the understanding's claims on us are in some sense justified. In light of Hume's meticulous and enthusiastic pursuit of his larger naturalistic project, one might even be tempted to conclude that Hume never really thought his sceptical arguments were sound. It would, however, be a mistake to submit to this temptation -- to do so would be to ignore the last part of book I of the Treatise, in which Hume evidently does find such arguments to be sound. Hume is undeniably impressed by scepticism about the