Learning from Words: Testimony as a Source of Knowledge

Testimony is an invaluable source of knowledge. We rely on the reports of those around us for everything from the ingredients in our food and medicine to the identity of our family members. Recent years have seen an explosion of interest in the epistemology of testimony. Despite the multitude of views offered, a single thesis is nearly universally accepted: testimonial knowledge is acquired through the process of transmission from speaker to hearer. This book shows that this thesis is false and, hence, that the literature on testimony has been shaped at its core by a view that is fundamentally misguided. A detailed alternative to this conception of testimony is then defended: whereas the views currently dominant focus on the epistemic status of what speakers believe, the book advances a theory that instead centers on what speakers say. The upshot is that, strictly speaking, we do not learn from one another's beliefs - we learn from one another's words. Once this shift in focus is in place, the book goes on to argue that though positive reasons are necessary for testimonial knowledge, testimony itself is an irreducible epistemic source. This leads to the development of a theory that gives proper credence to testimony's epistemologically dual nature: both the speaker and the hearer must make a positive epistemic contribution to testimonial knowledge. The resulting view not only reveals that testimony has the capacity to generate knowledge, but it also gives appropriate weight to our nature as both socially indebted and individually rational creatures.