Expert Opinion and Second-Hand Knowledge

Recent work on testimony and the norms of assertion considers cases of expert testimony. Thinking about expert testimony clarifies which epistemic goods figure in the expectations placed on experts for their knowledge. Examining the distinctive conditions of expert testimony and the assumptions hearers bring to such conversational contexts can provide broader lessons about how knowledge is represented by speakers, and how it is gained by hearers. Expert testimony is the focus of Jennifer Lackey’s (, ) recent arguments over the norm of assertion. Her cases suggest that experts are plausibly held to a different epistemic standard when speaking as experts, where this standard concerns not only the quantity of an expert’s epistemic support for what an expert asserts, but also the quality of that epistemic support. These cases seem to count against knowledge being sufficient for epistemically permissible assertion; and several others have followed Lackey in regarding such cases as important to adjudicating the debate over the norms of assertion and practical reasoning (Carter and Gordon , Coffman , McKinnon , Carter , Gerken , Green forthcoming). I shall argue in this paper that relying on intuitions about such cases of expert testimony introduces several problems concerning expertise, expert knowledge, and the sharing of such knowledge through testimony.