The epistemological puzzle testimony raises is this: Why is testimony a source of knowledge? An externalist might say that testimony is a source of knowledge if, and because, it comes from a reliable source. But here, even more so than in the case of our faculties, internalists will not find that answer satisfactory. Suppose you hear someone saying “p”. Suppose further that person is in fact utterly reliable with regard to the question of whether p is the case or not. Finally, suppose you have n