Evolution and Impartiality

Katarzyna de Lazari-Radek and Peter Singer argue that evolutionary considerations can resolve Sidgwick's dualism of practical reason because such considerations debunk moral views that give weight to self-interested or partial considerations but cannot threaten the principle of universal benevolence. I argue that even if we grant these claims, this appeal to evolution is ultimately self-defeating. De Lazari-Radek and Singer face a dilemma. Either their evolutionary argument against partial morality succeeds, but then we need to also give up our conviction that suffering is bad; or there is a way to defend this conviction, but then their argument against partiality fails. Utilitarians, I suggest, should resist the temptation to appeal to evolutionary debunking arguments.