Abstract

The repugnant conclusion poses a conundrum in population ethics that has evaded satisfactory solution for more than four decades. In this article, I show that the repugnant conclusion can be avoided without sacrificing any moral intuitions. The resulting framework satisfies Parfit's requirements for `theory X'. This is achieved using non-Archimedean orders, which admit the possibility of pairs of goods for which no amount of one is better than a single unit of the other. I show with minimal assumptions, not only are such goods sensible, they are compulsory. I show that utilitarianism and expected utility theory in their canonical forms are not in general suitable in this setting, and using these tools naively can lead to ethical errors that are arbitrarily serious. Multi-dimensional lexicographic expected utility representations are required. I use fuzzy sets to show there needn't be a clear boundary separating goods that are not Archimedean equivalent. This may be unavoidable due to intrinsic physical limits on the ability to discriminate between different goods arising from e.g. quantum mechanics. Limited discriminatory power causes preferences to be non-transitive, which can resolve problems related to so-called `fanaticism' and `recklessness' wherein `rational' decision-makers counterintuitively prefer arbitrary long shot bets to a guaranteed lesser outcome.