In the 17th and early 18th centuries in Britain, there were no clear divisions between what we now call moral epistemology, moral metaphysics, and normative moral theory. In this talk, Aaron Garrett argues that Francis Hutcheson, in refuting the work of Mandeville, attempted to make good on this long tradition of lumping these ideas together, and that this variant of a demonstrative moral science is both associated with the natural law tradition following from Grotius, and supportive of the ancient moralists.