 When applied, a science’s theory weeds out ideological notions associated with the original concept or genera. The result of this application of theory to genera is the transformation of the “ideological generality into a scientific generality” (1963b [2005], 185). An example of such a process is the transformation in medical science of a concept like “phlegmatic humors” into the idea of blood-borne pathogens by dint of the theory of circulation and infectious disease. Once generated, such scientific concepts inform regular scientific practice, allowing specific research programs within an individual science to progress. Althusser himself gives examples of three such major transformations. The first is the founding of modern physics by Galileo, the other that of Greek mathematics, and the third, that of Marx’s founding of the science of Historical Materialism out of Classical Political Economy. Each of these foundings is marked by what Althusser terms an “epistemological break,” or a period when ideological concepts are replaced by scientific ones. Any similarity here to Kuhnian ideas about revolutionary and normal science is not surprising. Both Canguilhem and Bachelard, from whom Althusser drew inspiration for his theory, were part of a dialogue that took in the work of Alexander Koyré on scientific revolutions, a thinker from whom Kuhn, in turn, drew his inspiration.