John McDowell begins his essay ‘Knowledge by Hearsay’ (1993) by describing two ways language matters to epistemology. The first is that, by understanding and accepting someone else's utterance, a person can acquire knowledge. This is what philosophers call ‘knowledge by testimony’. The second is that children acquire knowledge in the course of learning their first language—in acquiring language, a child inherits a conception of the world. In The Formation of Reason (2011), and my writings on Russian socio‐historical philosophy and psychology, I address issues bearing on the second of these topics, questions about the child's development through initiation into language and other forms of social being. In this article, I focus on the first: the epistemology of testimony. After expounding a view of testimony inspired by McDowell, and supplemented by ideas from Sebastian Rödl, I consider how such an account illuminates two issues in philosophy of education: the extent of an individual's epistemic dependence upon others, and the nature of teaching.