In the following contribution we seek to explore Michel de Certeau’s “furtive” reading of Michel Foucault’s notion of episteme in its relation to the event, to think the revolution. Based on his -at the same time-affinity and distance with this category, Certeau advances and elaborates the notion of “Formality of practices” (Formalité des pratiques), which will allow him a more complex and problematized reading of modernity and secularization than what Foucault offered him in Les mots et les choses.