David Hume opens his inquiry by debating whether moral distinctions stem from reason or sentiment, ultimately concluding that reason merely illuminates facts while an internal sense or feeling provides the final sentence of approbation or blame. He rejects purely selfish theories of human nature, demonstrating through careful observation that human beings possess a natural, disinterested concern for the well-being of others. The argument centers on public utility as the primary source of moral approval, particularly for social virtues like benevolence and justice. While benevolence acts directly through natural affection, justice is shown to derive its utility and moral obligation from its necessity in preserving civil order and protecting property within society.
Moving beyond purely social duties, Hume extends his analysis to personal merit and individual qualities that are either useful or immediately agreeable to the possessor or to others. Talents such as discretion, industry, and frugality, alongside physical and intellectual endowments, naturally command esteem because they promote personal happiness and success. Similarly, cheerfulness, wit, and good manners facilitate social intercourse and diffuse immediate satisfaction among companions. Throughout these examinations, Hume maintains that the same underlying principle of social sympathy governs our evaluation of both moral virtues and personal talents.
In the later sections, Hume addresses the practical obligations of morality and the self-interest found in virtue. He argues that moral conduct is invariably the true interest of each individual, bringing peace of mind, a clear conscience, and the genuine good-will of others. By stripping ethics of austere theological burdens and monkish rigors, he presents a naturalistic framework where virtue aims to make mankind cheerful and happy. The treatise concludes by reinforcing the harmonious division between reason, which discovers the tendencies of actions, and sentiment, which feels the moral distinction, ultimately establishing that human nature is fundamentally equipped with the social sentiments necessary for cooperative life.
