Examining the moral sense theories of Francis Hutcheson, David Hume, and Adam Smith from the perspective of the is-ought problem, this essay shows that the moral sense or moral sentiments in those theories alone cannot identify appropriate morals. According to one interpretation, Hume's or Smith's theory is just a description of human nature. In this case, it does not answer the question of how we ought to live. According to another interpretation, it has some normative implications. In this case, it draws normative claims from human nature. Anyway, the sentiments of anger, resentment, vengeance, superiority, sympathy, and benevolence show that drawing norms from human nature is sometimes morally problematic. The changeability of the moral sense and moral sentiments in Hume's and Smith's theories supports this idea. Hutcheson's theory is morally more appropriate because it bases morality on disinterested benevolence. Yet disinterested benevolence is not enough for morality. There are no sentiments the presence of which alone makes any action moral.