…also a joke

During the course of Seminar 19, “...Ou pire”, French psychoanalyst Jacques Lacan uttered one of those sentences that would become a headache for his followers: the only teaching is mathematical, the rest is a joke. However, this statement does not exclude the real possibility that mathematics might also ultimately be a great joke. The objective of this article is to show how this far from casual comment refers to one of the profoundest aspects of this discipline that, as many may suspect, began a few centuries before Lacan.