Testimony as a Basic Source of Knowledge

Testimony, in the epistemological sense, refers to any assertion offered by one person and taken up as a source of belief by another — a friend reporting the time of a meeting, a textbook stating a historical date, a newspaper describing an event none of its readers witnessed. Contemporary epistemologists estimate that the overwhelming majority of what any individual believes, from geography and history to basic facts about their own birth date, rests on testimony rather than on first-hand perception, memory, or inference, a point stressed by C.A.J. Coady in Testimony: A Philosophical Study (1992), the book that did more than any other single work to establish testimony as a distinct topic within analytic epistemology. Before Coady, testimony had been treated, if at all, as a peripheral or derivative topic, subsumed under inductive inference from perception and memory; his systematic treatment argued that this marginal status badly understated its role in the overall economy of human knowledge, since science itself, far from being purely observational, is saturated with testimonial reliance on the reports of other researchers, instruments calibrated by other technicians, and results published in journals no single scientist could independently re-derive.