CONCEPT
The Repugnant Conclusion
Derek Parfit’s name for the result that any population of wonderful lives is outweighed, on the total-welfare arithmetic, by a sufficiently enormous population of lives barely worth living—a paradox that is the hidden engine beneath every proposal to reason about vast numbers of future or artificial minds.
When Derek Parfit tried to build the impersonal ethics that the
non-identity problem demands—a framework that evaluates futures by the total or average welfare they contain rather than by harms to nameable individuals—he ran straight into a wall he named with characteristic precision the Repugnant Conclusion. The mechanism is disarmingly simple: a life barely worth living contributes a small positive amount to total welfare; enough barely-worth-living lives contribute more in total than any smaller number of wonderful ones. The most natural way of valuing futures therefore points relentlessly toward a “world of muzak and potatoes”—teeming and tepid, vast in number and minimal in quality—as preferable to any population of genuinely flourishing people. Parfit found this conclusion genuinely repugnant, spent decades attempting to find Theory X that would avoid it without generating equally bad alternatives, and failed. The Repugnant Conclusion is not a puzzle with a solution. It is