1INEXACT SCIENCES: PROFESSIONAL EDUCATION AND THE DEVELOPMENT OF EXPERTISE1

Professionals contribute to society in a variety of ways. They design buildings and bridges that will serve their clients ' purposes, prescribe drugs or perform surgery designed to rectify their patients' physical ailments or to make them more comfortable, decide what content to teach students and how to teach it, and defend clients. They share in common the ability to connect solutions to problems. And they are assumed to possess special expertise that enables them to do this. In this paper, I review literature on the nature of expertise and on how it is acquired. To do justice to the issues, I include important nonempirical, as well as empirical, literature. I also include empirical studies drawn from outside professional education literature, particularly from cognitive psychology. I review four definitions of expertise, each of which incorporates a different view about how expertise influences professional actions: expertise as technical skill, as application of theory, as critical analysis, and as deliberate action. Each succeeding definition remedies failures of earlier definitions, and in so doing each defines expertise as a more complicated phenomenon than its predecessor. But in the end, each definition is incomplete in some critical way. There is also a skeptical view of professional expertise, usually expressed outside profe sional education circles, which I allude to occasionally with the help of Molier. The view pervade