In The Descent of Man, Charles Darwin sought to erase the hard border between humans and other animals. Attempts to define a human exception within nature persist, however, among evolutionary anthropologists as well as in popular histories of the human species. Darwin proposes a cultural rather than biological perfection of “humanity” through an evolution of the moral sense or conscience, which takes the form of a deliberative expansion of the sympathetic imagination to embrace other nations and races and, eventually, all sentient life. At the same time, Darwin predicts a future widening of the extinction gap between a more highly evolved human type and “lower” races and species. Extermination, seemingly at odds with a universal sympathy, provides its historical condition. The crux informs subsequent accounts of a revolutionary rather than evolutionary stage of human emergence, in which the enhancement of Homo sapiens’ social intelligence entails the extermination of other human populations.