Path dependence, competition, and succession in the dynamics of scientificrevolution

What is the relative importance of structural versus contextual forces in t he birth and death of scientific theories? We describe a formal dynamic mod el of the birth, evolution, and death of scientific paradigms based on Kuhn 's Structure of Scientific Revolutions. The model represents scientific act ivity as a changing set of coupled institutions; a simulated ecology of int eracting paradigms in which the creation of new theories is stochastic and endogenous. The model captures the sociological dynamics of paradigms as th ey compete against one another for members, solve puzzles, and recognize an omalies. We use sensitivity tests and regression to examine the role of int rinsic versus contextual factors in determining paradigm success. We find t hat situational factors attending the birth of a paradigm largely determine its probability of rising to dominance, while the intrinsic explanatory po wer of a paradigm is only weakly related to the likelihood of success. For those paradigms surviving the emergence phase, greater explanatory power is significantly related to longevity. However, the relationship between a pa ra digm's "strength" and the duration of normal science is also contingent on the competitive environment during the emergence phase. Analysis of the model shows the dynamics of competition and succession among paradigms to b e conditioned by many positive feedback loops. These self-reinforcing proce sses amplify intrinsically unobservable microlevel perturbations in the env ironment-the local conditions of science, society, and self faced by the cr eators of a new theory-until they reach macroscopic significance. Such path dependent dynamics are the hallmark of self-organizing evolutionary system s. We consider the implications of these results for the rise and fall of n ew ideas in contexts outside the natural sciences such as management fads.