Dr. Nersessian is addressing a central question in the area of science and technology studies: how do new conceptual structures emerge in scientific revolutions. Philosophers and historians of science have been divided on the issue: some have viewed conceptual change in science as occurring suddenly, often as a psychological Gestalt switch; others have viewed change as extended over a long period of time. This project seeks to show how a more refined understanding of conceptual change can be achieved by combining the short-term cognitive -- or psychological -- approach with the long-term historical one. It does so on the basis of two premises. First, the extant literature has demonstrated that conceptual change in science is rarely, if ever, sudden. Hence, in order to understand the evolution of conceptual change, the temporal perspective of history is needed. Second, conceptual change in science has its roots in ordinary thinking; the representational and problem-solving practices of scientists and outgrowths and refinements of ordinary cognitive resources. This investigation unites the resources of two methods normally kept separate by applying a new interdisciplinary method that deploys modern tools of cognitive analysis in fine-structure long- term examinations of theoretical and experimental practices responsibly for major conceptual innovations.
