Hume begins with the observation that there is much variety in people's taste (or the aesthetic judgments people make). However, Hume argues that there is a common mechanism in human nature that gives rise to, and often even provides justification for, such judgments. He takes this aesthetic sense to be quite similar to the moral sense for which he argues in his Book 3 of A Treatise of Human Nature (1739–1740) and in An Enquiry Concerning the Principles of Morals (1751).