Scholars have long attempted to understand the nature of scientific change. Is science characterized by the steady application of universally-accepted norms of logical inquiry, or is it an enterprise that periodically reconstructs itself from new fundamentals? One of the best-known examples of the latter view is Thomas S. Kuhn’s Structure of Scientific Revolutions. Kuhn argues that new theories replace old ones rather than build upon them, and in the process revolutionize science’s very image of itself (1962:84-85). Scientific progress is seen not as a steady accumulation of truths, but “as succession of tradition-bound periods punctuated by non-cumulative breaks” ( Kuhn 1970:208). Kuhn’s theory has had enormous influence in the social sciences, but it is also of enduring interest in the physical sciences (Barnes 1982; Lightman and Gingerich 1992). The notion of paradigm has, rightly or wrongly, been used to legitimate alternative methods of research as well as to delegitimate dominant modes of inquiry. Nonetheless, although ‘paradigm competition’ has become well-established in the academic lexicon, little is known about what such competition actually entails. How do internal and contextual forces interact to shape and constrain the development of new paradigms? Why do some paradigms last for centuries while others quickly wither?