In what follows, I appeal to Charles Babbage’s discussion of the division of mental labor to provide evidence that—at least with respect to the social acquisition, storage, retrieval, and transmission of knowledge—epistemologists have, for a broad range of phenomena of crucial importance to actual knowers in their epistemic practices in everyday life, failed adequately to appreciate the significance of socially distributed cognition. If the discussion here is successful, I will have demonstrated that a particular presumption widely held within the contemporary discussion of the epistemology of testimony—a presumption that I will term the personalist requirement—fails to account for those very practices of knowers that I detail here. I will ...