  In the latter work, Hume’s main argument that reason alone is not adequate to yield moral evaluations (in Appendix 1) depends on his having demonstrated throughout the book that at least one foundation of moral praise lies in the usefulness to society of the praised character trait. We use reason extensively to learn the effects of various traits and to identify the useful and pernicious ones. But utility and disutility are merely means; were we indifferent to the weal and woe of mankind, we would feel equally indifferent to the traits that promote those ends. Therefore there must be some sentiment that makes us favor the one over the other. This could only be humanity, “a feeling for the happiness of mankind, and resentment of their misery” (EPM App. 1.3). This argument presupposes that the moral evaluations we make are themselves the expression of sentiment rather than reason alone. (The alternative position would be that while of course we do feel approval and disapproval for vice and virtue, the judgment as to which is which is itself the deliverance of reason.) So Hume appends some arguments directed against the hypothesis of moral rationalism. One of these is an enriched version of the argument of Treatise 3.1.1 that neither demonstrative nor causal reasoning has moral distinctions as its proper object, since moral vice and virtue cannot plausibly be analyzed as either facts or relations. He adds that while in our reasonings we start from the knowledge of relations or facts and infer some previously-unknown relation or fact, moral evaluation cannot proceed until all the relevant facts and relations are already known. At that point, there is nothing further for reason to do; therefore moral evaluation is not the work of reason alone but of another faculty. He bolsters this line of argument by expanding his Treatise analogy between moral and aesthetic judgment, arguing that just as our appreciation of beauty awaits full information about the object but requires the further contribution of taste, so in moral evaluation our assessment of merit or villainy awaits full knowledge of the person and situation but requires the further contribution of approbation or disapprobation. He also offers the argument that since the chain of reasons why one acts must finally stop at something that is “desirable on its own account… because of its immediate accord or agreement with sentiment…” (EPM App.1.19), sentiment is needed to account for ultimate human ends; and since virtue is an end, sentiment and not reason alone must distinguish moral good and evil.