Responsible public policy making in a technological society must rely on complex scientific reasoning. Given that ordinary citizens cannot directly assess such reasoning, does this call the democratic legitimacy of technical public policies in question? It does not, provided citizens can make reliable second-order assessments of the consensus of trustworthy scientific experts. I develop criteria for lay assessment of scientific testimony and demonstrate, in the case of claims about anthropogenic global warming, that applying such criteria is easy for anyone of (...) ordinary education with access to the Web. However, surveys show a gap between the scientific consensus and public opinion on global warming in the U.S. I explore some causes of this gap and argue that democratic reforms of our culture of political discourse may be able to address it. (shrink)

Mainstream epistemology is a highly theoretical and abstract enterprise. Traditional epistemologists rarely present their deliberations as critical to the practical problems of life, unless one supposes—as Hume, for example, did not—that skeptical worries should trouble us in our everyday affairs. But some issues in epistemology are both theoretically interesting and practically quite pressing. That holds of the problem to be discussed here: how laypersons should evaluate the testimony of experts and decide which of two or more rival experts is most (...) credible. It is of practical importance because in a complex, highly specialized world people are constantly confronted with situations in which, as comparative novices, they must turn to putative experts for intellectual guidance or assistance. It is of theoretical interest because the appropriate epistemic considerations are far from transparent; and it is not clear how far the problems lead to insurmountable skeptical quandaries. This paper does not argue for flat-out skepticism in this domain; nor, on the other hand, does it purport to resolve all pressures in the direction of skepticism. It is an exploratory paper, which tries to identify problems and examine some possible solutions, not to establish those solutions definitively. (shrink)

The first section of this paper explains why assessing the worth of expert testimony poses special epistemological difficulties. The second traces the history of the various rules and procedures by means of which the U.S. legal system has tried to ensure, or at least control, the quality of the expert testimony on which it so often relies—from the Frye Rule, the Federal Rules of Evidence, and the Daubert trilogy to recent constitutional cases regarding the appearance of forensic witnesses in court (...) and experiments with court-appointed experts and scientific education for judges. The third and final section suggests some lessons to be learned from the limited success of these efforts, and explores what might be better strategies going forward. (shrink)

Scientific expert testimony is crucial to public deliberation, but it is associated with many pitfalls. This article identifies one—namely, expert trespassing testimony—which may be characterized, crudely, as the phenomenon of experts testifying outside their domain of expertise. My agenda is to provide a more precise characterization of this phenomenon and consider its ramifications for the role of science in society. I argue that expert trespassing testimony is both epistemically problematic and morally problematic. Specifically, I will argue that scientific experts are (...) subject to a particular obligation. Roughly, this is the obligation to qualify their assertions when speaking outside their domain of scientific expertise in certain contexts. Thus, I argue that scientists who possess expert knowledge are confronted with hard questions about when and how to testify and, therefore, that being a scientific expert comes with great responsibility. Consequently, I provide a concrete “expert guideline” according to which scientific experts, in certain contexts, face an obligation to qualify their assertions when speaking outside their domain of expertise. Furthermore, I consider a number of the conditions in which the guideline is waived or overridden. On this basis, I consider the broader aspects of the roles of scientific experts in a society with a high division of cognitive labor that calls for trust in scientific expert testimony. (shrink)