La place de la mathématique : Badiou avec Lacan

The paper attempts to give an account of two different ways of relating to mathematics: Lacan’s and Badiou’s. Its starting point is Badiou’s and Lacan’s interpretations of Russell’s infamous definition of mathematics, according to which mathematics is a discourse in which no one knows what one is talking about, nor whether what one is saying is true. While for Badiou, the ignorance that is supposed to characterise mathematics according to Russell only concerns the role philosophy assigns to it, namely, it being identified with the science of being qua being, for Lacan the ignorance constitutive of mathematics should rather be seen as a symptom resulting from the reduction of truth to a mere truth value. In discussing the detected divergences in these two readings, the paper shows how the access to psychoanalysis as well as the access to philosophy coincides with a certain access to mathematics, although we are not dealing with the same type of access.