 Another crucial feature of Diderot’s ethics was his dislike for relativism or at least for some of its possible consequences. Diderot learned a great deal from Locke, Montaigne and other paragons of early Western cultural relativism. Montaigne and Locke paid close attention to the case of cannibals; Locke, when he takes up the case of cannibals in the Essay, uses it to support anti-innatist views with respect to what he calls “practical principles” (that is, moral principles of conduct): he points out that the Tupinamba tribe in the Amazon considers that a high form of virtue is eating one’s enemies, along with many other examples of “enormities practised without remorse”, in order to stress that “moral rules” are not innate but culturally specific and learned (Locke 1690 [1975: I.iii.9]). The challenge is not to morals per se but to “mores” and customs which we take to encapsulate morality. Diderot echoes these ideas notably in his Supplément au voyage de Bougainville, but contrary to widespread views, he did not think that such relativism had to entail libertinage, criticizing Hemsterhuis for reasoning “as if libertinage was a necessary consequence of materialism, which seems to me to match neither reason nor experience” (OH; DPV XXIV: 251). Unlike La Mettrie (and the Marquis de Sade after him), Diderot maintained a strongly social concept of self. “He who has studied himself”, he wrote, “will have advanced in the knowledge of others, given, I think, that there is no virtue which is foreign to the wicked, nor vice foreign to the good” (ERCN; DPV XXV: 226).While he did not develop a full-fledged theory of sympathy like Hume or Smith, Diderot was nevertheless acutely conscious of the role of the passions in cementing the social bond, and how this role should be promoted in any viable ethical theory.