And as this is the obvious appearance of things, it must be admitted, till some hypothesis be discovered, which by penetrating deeper into human nature, may prove the former affections to be nothing but modifications of the latter. All attempts of this kind have hitherto proved fruitless, and seem to have proceeded entirely from that love of simplicity which has been the source of much false reasoning in philosophy.

An Enquiry Concerning the Principles of Morals. By David Hume Esq (ed. 1751)