Expertise and the courts

Date of Award




Degree Name

Doctor of Philosophy (Ph.D.)



First Committee Member

Susan Haack - Committee Chair


In this dissertation, I explore whether laypersons, particularly individuals who serve as judges and juries, are capable of understanding and evaluating specialized claims adequately. Although I will be unable to do justice to all of the interesting questions that need to be sorted out, I try to pinpoint issues that I feel have often been overlooked or neglected while the practice of allowing experts to testify in the courts continues. Our knowledge of the world continues to increase, and with it, so does the number of specialized issues and fields. Hence, as our legal system tries to keep up and evaluate the claims of the ever-increasing number of "experts" that appear in courtrooms, its struggles may only get more pronounced as the complexity of legal cases grows.In chapter 1, I will review the history of how expert witness testimony has been handled by our legal system. I discuss federal rules and cases that set forth guidelines for determining whether courts should admit proffered expert testimony.In chapter 2, I will address questions pertaining to the nature of expertise. I begin by reviewing definitions of expertise. Then, I pinpoint differences between an expert and a layperson. Also, I discuss why we rely on experts and how expertise can be verified.In chapter 3, I will discuss the issue of whether laypersons can understand and assess the claims of experts. I focus on how differences between laypersons and experts can cause problems for the legal system. Lay judges and juries are charged with evaluating a vast array of specialized claims. Yet they will find at least some of these claims to be inaccessible. This is largely due to the inherent complexity of some specialized claims and the adversarial manner in which these claims are presented.In chapter 4, I will explore the legal system's interaction with science. The testimony of scientific expert witnesses tends to pose a difficult problem for the courts. Because of the complex and technical nature of some scientific claims, judge and juries can face a rather daunting task when they try to assess the worth of these claims. Further, the legal system has drawn itself into philosophical debates about science, including whether there is a scientific method, that it cannot hope to resolve.In chapter 5, I will offer suggestions that may help the courts handle expert testimony more effectively. In cases where the judge or jury can understand the proffered specialized claims but there is not sufficient evidence to assess their worth, more extensive proficiency testing needs to be performed. Further, court-appointed experts should be used more consistently in cases where the specialized issues in dispute are inaccessible to lay judges or juries.


Law; Philosophy

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