English Law's Epistemology of Expert Testimony


  • Thanks to Luca Malatesti and Chris Slobogin for their many helpful suggestions on epistemology and United States law respectively, to Phil Bielby, Massimo la Torre, Joelle Moreno, Peter Paulden, and Suzanne Uniacke for their comments on various drafts, to Andrew Roberts for sharing his forthcoming work, and to the anonymous referees for their detailed and constructive comments.


The decision whether to believe an expert witness raises difficult epistemological and ethical questions for a lay juror or judge. This article examines the English courts' approach to these questions in the light of a series of cases which endorse the test of admissibility formulated in the Australian case o/R v. Bonython. It argues that, if interpreted more rigorously than it generally has been to date, Bonython could provide the framework for an approach which avoids the pitfalls of either a ‘scientistic’ or a ‘constructivist’ epistemology of expert testimony. Such an approach needs to distinguish between different types of expertise and the differing degrees of deference that they call for on the part of a lay fact-finder.