As Darwin’s readers have often noted, he was enthusiastic about the explanatory reach of his theory. Everyone knows of Darwin’s promissory note in the Origin (1859, 448): “In the distant future I see open fields for more important researches. Psychology will be based on a new foundation, that of the necessary acquirement of each mental power and capacity by gradation.” Of course, evolutionary approaches to psychology have been prevalent for some time now; however, theorists from philosophy and the sciences have wondered if knowledge itself – understood as a state of mind, to be explained in scientific terms – might also be approached from the perspective of an evolutionarily informed psychology. This essay gives a selective overview of some of the projects we might collect under the heading of “evolutionary epistemology” and of the likely limits to using evolution to shed light on what knowledge is and how much of it we have.

One of the best-known essays on Darwin’s broader impact is John Dewey’s “The Influence of Darwinism on Philosophy,” originally delivered as a lecture in 1909. Darwin taught us that species were malleable, ephemeral; that there was no hard-and-fast distinction between good species and mere varieties; and that we should expect no rigorous answer to be had to the questions of when, precisely, a new species has been created or what sort of a thing a species is (Fig. 56.1). As Dewey (1910, 5) notes near the beginning of his essay,