The empirical study of the « water memory » controversy allows us to discuss the relevance of the “antidifferenciationnist” thesis in sociology of science. If the detailed study of the controversy over the “memory of water” shows that its dynamics is combined with opening confrontation arenas, thus resulting in a secularization of the academy and a blurring of boundaries, it reveals that debates develop in compliance with a set of epistemic norms that escape definition conflicts and finally demonstrate the existence of a demarcated social space in which the actors are subject to specific norms.