  One is a question of moral epistemology: how do human beings become aware of, or acquire knowledge or belief about, moral good and evil, right and wrong, duty and obligation? Ethical theorists and theologians of the day held, variously, that moral good and evil are discovered: (a) by reason in some of its uses (Hobbes, Locke, Clarke), (b) by divine revelation (Filmer), (c) by conscience or reflection on one’s (other) impulses (Butler), or (d) by a moral sense: an emotional responsiveness manifesting itself in approval or disapproval (Shaftesbury, Hutcheson). Hume sides with the moral sense theorists: we gain awareness of moral good and evil by experiencing the pleasure of approval and the uneasiness of disapproval when we contemplate a character trait or action from an imaginatively sensitive and unbiased point of view. Hume maintains against the rationalists that, although reason is needed to discover the facts of any concrete situation and the general social impact of a trait of character or a practice over time, reason alone is insufficient to yield a judgment that something is virtuous or vicious. In the last analysis, the facts as known must trigger a response by sentiment or “taste.”