ABSTRACT
If our only sources of knowledge and justified belief were perception, consciousness, memory, and reason, we would be at best impoverished. We do not even learn to speak or think without the help of others, and much of what we know depends on what they tell us. Children in their first few years of life depend almost entirely on others to learn about the world. In talking about our dependence, for knowledge and justification, on what other people say to us, philosophers have commonly spoken of our reliance on their testimony. If perception, memory, consciousness, and reason are our primary individual sources of knowledge and justification, testimony is our primary social source of them. There are various kinds of testimony,
however, and there are many questions about how one or another kind yields knowledge or justification.
