Adam Smith’s Theory of Moral Sentiments (TMS) has long been recognized as importantly influenced by, and in part responding to, David Hume’s earlier ethical theory. With regard to Smith’s account of the foundations of morals in particular, recent scholarly attention has focused on Smith’s differences with Hume over the question of sympathy. Whilst this is certainly important, disagreement over sympathy in fact represents only the starting point of Smith’s engagement with–and eventual attempted rejection of–Hume’s core moral theory. We can see this by recognizing the TMS’s account of moral foundations as predicated upon a rejection of Hume’s distinction between the natural and artificial virtues. Smith is in turn revealed as generating a major break with Hume–a break which, if based on a superior theory of moral foundations (as Smith thought it to be) has important consequences for how we treat Smith and Hume in both the history of philosophy and contemporary moral theory.