This paper analyses the consequences of young researchers' scientific choice on the dynamics of sciences. We develop a simple two state mean field game model to analyse the competition between two paradigms based on Kuhn's theory of scientific revolution. The dynamics of the model are driven by the scientific choice of young researchers at the beginning of their career. Despite the possibility of multiple equilibria, the model exhibits at least one stable solution in which both para digms coexist. The occurrence of shocks on the parameters may induce the shift from one paradigm to the other. During this shift, researchers' choice is proved to be having a great impact on the evolution of sciences.