ABSTRACT
The logic underlying the scientific classification of sex is that of class and attribute, and dates from Aristotle: an individual with a particular attribute will be in the class of males; an individual without this attribute will be in the class of females. Compared with the fundamental absence of knowing, the child’s elaborate ratiocination is, according to S. Freud, organized in conceptual oppositions which follow the stages of sexual development: this is the dominant modality of jouissance that governs thinking. The clinic shows that the system of signifying oppositions is the model for the subject’s speech, and therefore for his thinking, well before it could be imputed to any observation of anatomical difference. The disturbing arrival of a baby poses the question of his origins, which will require considerable epistemic efforts on his part, and will lead to the creation of infantile sexual theories.
