In this final part, Hume discusses “natural virtues,” meaning those virtues that come directly out of human nature. Hume sees sympathy as the best explanation for how these virtues operate in human psychology. Sympathy is so strong a force that just the passion coming out of these virtues or their causes in another person is enough to make us share in it. Hume argues that the natural virtues serve the public interest, like artificial virtues (629)—we have sympathy with the pleasure other people gain from the natural virtues and the public interest they serve. This process happens both with those close to us and with complete strangers. We are capable of “general judgments” (633) which we can apply to anyone. This does not just apply to the natural virtues. In our general judgments, we can overlook our own self-interest and sympathize with someone who opposed or hurt us, and have sympathy for someone else’s, even a stranger’s, vices.

Hume suggests that each natural virtue is either good for the interest of others, good for our own self-interest, immediately agreeable to others, or immediately agreeable to ourselves (640-41). Examples of virtues good for our interest include the natural virtues of prudence and thrift with money, which would also benefit others.