Repugnance or Intransitivity: A Repugnant But Forced Choice

A set of arguments shows that either the Repugnant Conclusion and its variants are true or the better-than relation isn't transitive. Which is it? This is the most important question in population ethics. The answer will point the way to Parfit's elusive Theory X. In many ways, Derek Parfit's Reasons and Persons is the natural successor to Henry Sidgwick's The Methods of Ethics. Sidgwick's book was the greatest work in ethics of the 19th century; Parfit's was the greatest work in ethics of the 20th century. Each is the magnum opus of an English utilitarian, though neither is narrowly utilitarian. Sidgwick's methods of ethics— Egoism, Intuitionism, and Utilitarianism—correspond to Parfit's 'S,' 'M' and 'C'—the Self-interest Theory, Common-Sense Morality, and Consequentialism—which are key players in about half of Parfit's book. And Parfit can claim to solve Sidgwick's biggest problem: Sidgwick embraces Utilitarianism and Egoism yet cannot resolve the " fundamental contradiction " between them; Parfit interprets Egoism as a theory of rationality and claims to refute it. i Parfit's book stands a better chance of being widely read in the 23rd century. Even now, Sidgwick is not read much. There are several reasons for this. Sidgwick's subtle discussions of moral psychology have inspired few research programs among professional ethicists; his prose is dry; his book is long; and it is not clear which parts of it to read, since it is of fairly even quality.