An evidentialist epistemology of testimony

Thesis (Ph. D.)--University of Rochester. Department of Philosophy, 2016.This dissertation develops an evidentialist epistemology of testimony that is internalist in that only mental states are evidence, reductionist in that testimony needs independent evidence to justify beliefs, consistent with recent empirical work in psychology, and consistent with common sense about the extent of testimonial justification. There is a common impression that internalism and evidentialism are committed to skepticism and at odds with empirical research. I show that, with respect to testimony, these charges are unfounded. Chapter 1 develops the Higher-Level Account of Testimonial Evidence (HLA). I argue that testimonial evidence for any p consists in evidence that some testimony we have received was produced by evidence for p that the speaker possesses. In Chapter 2, I make a case for the “evidence of evidence principle” that HLA makes use of and defend it against a series of objections. Chapter 3 is dedicated to constructing two anti-reductionist arguments that threaten HLA. The first is the “Not Enough Evidence Objection” (NEEO) that argues that our testimony-independent evidence is insufficient for HLA to avoid skepticism. The second is the “Infant-Child Objection,” (ICO) according to which HLA is committed to skepticism about the beliefs of young children. Chapter 4 rebuts the NEEO. The first starts from H. P. Grice’s “Cooperative Principle,” arguing that the kind of evidence we need for interpreting what we are told includes evidence about the evidence others possess. The second makes an extended explanationist case for the same conclusion. Chapter 5 extends Chapter Four’s arguments to the case of very young children, arguing that at least some of the current psychological theories undermine the ICO. A final section takes up the possibility that accepting skepticism about the beliefs of some children is not as repugnant to common sense as might be urged. Chapter 6 explores some psychological models of testimonial belief formation, arguing that HLA is capable of accounting for not only our propositional justification for believing testimony, but our doxastic justification as well