KUHNS THEORY OF SCIENTIFIC REVOLUTIONS AND COGNITIVE-PSYCHOLOGY

In a previous article toe have shown that Kuhn's theory of concepts is independently supported by recent research in cognitive psychology. I n this paper we propose a cognitive re-reading of Kuhn's cyclical mode l of scientific revolutions: all of the important features of the mode l may note be seen as consequences of a more fundamental account of th e nature of concepts and their dynamics. We begin by examining incomme nsurability, the central theme of Kuhn's theory of scientific revoluti ons, according to two different cognitive models of concept representa tion. We provide new support for Kuhn's mature views that incommensura bility can be caused by changes in only a few concepts, that even inco mmensurable conceptual systems can be rationally compared, and that sc ientific change of the most radical son-the type labeled revolutionary in earlier studies-does not have to occur holistically and abruptly, but can be achieved by a historically more plausible accumulation of s maller changes. We go on to suggest that the parallel accounts of conc epts found in Kuhn and in cognitive science lead to a new understandin g of the nature of normal science, of the transition from normal scien ce to crisis, and of scientific revolutions. The same account enables us to understand how scientific communities split to create groups sup porting new paradigms, and to resolve various outstanding problems. In particular, we can identify the Kind of change needed to create a rev olution rather precisely. This new analysis also suggests reasons for the unidirectionality of scientific change.