Toward the end of The Descent of Man , Darwin made a striking assertion. “I would as soon be descended,” he claimed, from a “heroic little monkey” than from a “savage” who practiced torture and infanticide, treated “wives like slaves,” and was indecent and superstitious. These lines have been often quoted but rarely analyzed. I argue here that they provide a means for following Darwin’s thought as he grappled with contemporary ethnological evidence that seemed—if today’s “savages” were to be taken as models for primeval humans—to work against his theory of sexual selection as it applied to humankind. In addition to explicating what I suggest is a crucial element of Descent , this paper has three aims, all of which help us better understand the relationships between ethnology and Darwinian thought. First, to offer a selective intellectual history of British ethnology between 1864 and 1871, focusing on those texts that Darwin deemed most problematic for his arguments. Second, and as a result, to better specify Darwin’s views on race by comparing him not to his opponents, but to his like-minded peers, a group I term “liberal racialists.” Third, to explore the utility of what I term the “geological analogy,” a mid-nineteenth-century version of the comparative method (which substituted study of “less developed” peoples today for humans in much earlier periods). Where liberal ethnologists deployed the geological analogy consistently, Darwin would be much more selective, denying its application at times in favor of analogies to lower animals. He would thus save his theoretical suppositions by denying that contemporary “lower” races, with their depraved morality, could serve as appropriate models for our apparently more decent, yet more animalistic forebears.

Darwin used taxonomic arguments widely in his work on transformism and natural selection, especially in attempts to persuade other (typically non-transformist) naturalists of the correctness of his ideas in Origin of Species. But, as has long been noticed, classificatory practices in natural history were by no means turned on their head in the wake of his work. Darwin succeeded in coopting, or else leaving untouched, the taxonomic conclusions of his colleagues, because he needed to use their conclusions as evidence for his transformist views: time and again, he made points by referring to what a typical naturalists would make of things. By telling them that the kind of knowledge that their taxonomy produced was really about genealogical relationships, Darwin tried to tell naturalist that their judgments were correct even though they had not previously known why this was so: they were sleepwalkers, finding their way in the dark, and Darwin would illuminate them. His argumentative style continually attempted to draw existing practices of classification to his assistance, and made the judgments of his colleagues into surrogate phenomena that would provide evidence for his views. Those colleagues thus constituted a society that established nature by its own practices.