William C. Wimsatt is a professor of philosophy, a member of the Committee on Evolutionary Biology, and the Committee on the Conceptual Foundations of Science. His work centers on the philosophy of the inexact sciences--biology, psychology, and the social sciences--the history of biology, and the study of complex systems. Professor Wimsatt focuses primarily on a cluster of problems arising in the analysis of the structure, behavior, and evolution of complex, functionally organized systems.