The moment of rupture separating science from its non-scientific past. After the rupture the non-scientific past comes to be seen as so much superstition. In this way, the history of science is understood not so much a process of discovery as the overcoming of the obstacles to thought posed by knowledge itself. It thus entails not simply the addition of new knowledge, but the reorganization of the very possibility of knowledge. It changes the conditions of what is and can be known. The concept was conceived by Bachelard, Gaston and further developed by Canguilhem, Georges, but it is perhaps the work of Foucault, Michel which has done the most to demonstrate the importance of this concept by taking it outside of the strictly scientific domain Bachelard and Canguilhem remained in. Foucault described epistemological breaks not only in the history of medicine, but also in the history of prisons, sexuality, and psychiatry.