This paper states three counterexamples to the claim that testimony cannot generate knowledge, that a hearer can only acquire testimonial knowledge from a speaker who knows: a twins case, the fossil case, and an inversion case. The paper provides an explanation for why testimony can generate knowledge. Testimonial knowledge involves the flow of information from a speaker to a hearer through the linguistic channel.

Our folk epistemology says that if someone knows that P and tells you that P, then, given the absence of defeaters, if you believe what they tell you, you will come to know that P as well. A speaker's knowledge that P is then, for the most part, enough for a hearer to come to know that P. But there are counterexamples to this principle: testimonial knowledge does not always transfer from the speaker to the hearer. Why should that be (...) so? Because testimonial knowledge arises through the flow of information--from conclusive grounds--from the speaker through the speaker's assertion to the hearer's state of comprehension as of the speaker's assertion. A speaker's belief can be based on conclusive grounds, but the speaker's assertion may fail to provide conclusive grounds to the hearer. Then the hearer won't acquire knowledge, even from a knowledgeable speaker. Knowledge from testimony then works more like knowledge through perception. But wait, you say, that can't be so because testimony involves free will but perception does not. The essay ends with a broadly Hume inspired reply to this objection. (shrink)

This paper challenges the standard conception of memory as a form of knowledge. Unlike knowledge, memory implies neither belief nor justification.

According to internalist theories of testimony, beliefs based on what others say are justified by the reasons a listener uses in forming her belief. I identify a distinctive type of testimonial situation, which I call circular testimony and argue that a certain type of circular testimony establishes the incompleteness of internalist theories of testimony.

Theories of epistemically justified belief have long assumed individualism. In its extreme, or Lockean, form individualism rules out justified belief on testimony by insisting that a subject is justified in believing a proposition only if he or she possesses first-hand justification for it. The skeptical consequences of extreme individualism have led many to adopt a milder version, attributable to Hume, on which a subject is justified in believing a proposition only if he or she is justified in believing that there (...) is testimony in favor of the proposition deriving from a reliable source. I argue that this Humean individualism also leads to skepticism in a wide range of cases; it makes it impossible for a layperson to be justified on expert testimony. In addition, I argue that the apparent motivation for the Humean view, an insistence on intellectual autonomy in justification, does not succeed in motivating it. I then explore the contours of a collectivist view of justification on testimony, with special attention to the place of a subject's intellectual autonomy in such justification. I try to bring empirical results of the psychology of persuasion to bear on the epistemological issues. (shrink)

Philosophical Quarterly 51:205, 512-26 (October 2001).

I discuss the conjecture that understanding what is said in an utterance is to be modelled as knowing what is said in that utterance. My main aim is to present a number of alter- native models, as a prophylactic against premature acceptance of the conjecture as the only game in town. I also offer preliminary assessments of each of the models, including the propositional knowledge model, in part by considering their respective capacities to sub-serve the transmission of knowledge through testimony. (...) In each case, the preliminary assessment is unfavourable. I end by very briefly sketching an additional model as an object for future consideration. (shrink)