The Methods of Ethics

A long, careful treatise first published in 1874 and revised by Sidgwick through several editions, the last appearing in 1907, after his death in 1900. Rather than defend a theory from the start, it examines the three main 'methods' by which people decide what they ought to do: egoism, which aims at one's own greatest happiness; intuitionism, which relies on the rules of common-sense morality; and utilitarianism, which aims at the greatest happiness of all. Book III tests common-sense duties such as justice, truthfulness and benevolence, finds them vague or conflicting, but finds a few self-evident axioms that survive, including prudence, justice as impartiality and rational benevolence: the good of one person is of no more importance, from the point of view of the universe, than the good of any other. Book IV argues that utilitarianism systematises common sense. Yet Sidgwick finds no rational way to settle the conflict between egoism and utilitarianism, which he calls the dualism of practical reason.

Many philosophers regard it as the most careful work of classical utilitarianism, and its method of testing theories against considered moral judgements set the pattern for later ethics, including Rawls.