Abstract

Traditional approaches to theory structure and theory change in science do not fare well when confronted with the practice of certain fields of science. We offer an account of contemporary practice in molecular biology designed to address two questions: Is theory change in this area of science gradual or saltatory? What is the relation between molecular biology and the fields of traditional biology? Our main focus is a recent episode in molecular biology, the discovery of enzymatic RNA. We argue that our reconstruction of this episode shows that traditional approaches to theory structure and theory change need considerable refinement if they are to be defended as generally applicable. 1This paper emerged from discussions between us, and we are both equally responsible for its errors. We would like to thank Yvonne Paterson for helpful comments.