Testimonial Knowledge from Lies

Recently, Dan O’Brien has argued that there are situations in which a hearer can gain testimonial knowledge from a speaker who is lying. In order to make his case, O’Brien presents two examples where a speaker lies to a hearer, but supposedly the hearer comes to have testimonial knowledge on the basis of the lying speaker’s testimony. O’Brien claims that his examples demonstrate that lies can be used to pass on knowledge in a non-inferential fashion. I argue that O’Brien is mistaken. More specifically, I argue that the hearer’s belief in the second example that O’Brien depicts fails to meet two plausible conditions for knowledge. First, the hearer’s belief fails to satisfy the requirements of the epistemic basing relation. Second, the hearer’s belief is not safe.