Making sense of forensic science evidence

Abstract

This chapter surveys the current landscape of forensic science and expert witness testimony, from the perspective of an English legal scholar. It attempts to ‘make sense’ of this massive, diverse, fragmented and somewhat contested terrain, which the author has studied for over two decades. Having listed no fewer than 20 different ways in which forensic science evidence has been viewed as problematic by commentators and critics, the chapter elucidates the epistemological grounds for rational reliance on expert evidence and considers the structural properties and resilience of the regulatory and procedural frameworks which govern this type of evidence in England and Wales. The chapter then turns its attention to the ‘intellectual resources’ of ‘forensic science’, understood expansively to include models of evidential interpretation and frameworks for structuring inferential reasoning (including ‘Bayesian’ approaches). The complexity and dynamism of the regulatory challenge of guaranteeing the reliability of forensic science evidence are stressed as central to fuller comprehension. Legal scholars have tended to focus on doctrinal issues, especially the task of formulating suitable evidentiary rules to regulate the admissibility of forensic science evidence in contested trials. Further reflection quickly demonstrates that admissibility is not the only doctrinal question posed by forensic science (and other expert) evidence; and moreover, doctrinal questions barely scratch the surface of the broader and deeper institutional, scientific, socio-legal and jurisprudential ‘problematic’ of forensic science sketched in this chapter.