Abstract

The purpose of this project is to examine the use of scientific testimony within Canadian courts and address the following issues: does scientific testimony pose a problem for the epistemic task of the trier of fact and, if so, what legal procedures will best meet the epistemic needs of the law? In order to answer the first question this dissertation develops an epistemology of testimony suitable for application to the courtroom environment. I argue that legal inquiry is a justificational context where our priority rests with error avoidance. This means that justification in the legal context is internalist in character, requiring that the legal fact-finder possess reasons for factual determinations. These heightened justifcatory requirements permit us to identify the problem that scientific testimony poses to inexpert courtroom determinations of fact. Lay triers of fact are called upon to evaluate expert testimony that they lack the requisite background knowledge and experience to assess. ;I proceed to investigate three legal responses to the problem posed by scientific testimony: inclusionary, exclusionary, and non-adversarial. The inclusionary approach to evidence that purports to address the deficiencies of lay fact finders through the adversarial presentation of evidence. Another common legal response is to paternalistically seek to shield the legal fact-finder from evidence that may distort the fact-finding process. This is what I describe as an exclusionary approach to evidence. It seeks to mitigate the epistemic dangers of scientific testimony through the application of a standard of admissibility that will ensure that only reliable testimony comes before the trier of fact. The last legal response that I consider involves the incorporation of non-adversarial procedures into our system of law to mitigate the epistemic dangers of scientific testimony by removing or limiting party control over the presentation of scientific evidence. I argue that all three responses expose shortcomings. ;Using the conclusions drawn from my analysis of these three responses I conclude by recommending an exclusionary approach that remains adversarial in character. I propose a procedure that utilizes reliability-based criteria in a trial judge's assessment of the evidence and introduces procedures for the use of independent court-appointed experts as 'judge's aids' in order to redress the difficulties identified with exclusionary approaches