Sex is, then, the impossibility of completing mean­ing. ... Sex is the structural incompleteness of language, not that sex is itself incomplete. ... The Kantian argument wants to desubstantialize sex. It links sex to the conflict of reason with itself, not simply to one of the poles of the conflict. This constitutes a more radical desubstantialization of sex, a greater sub­version of its conception as substance, than the one attempted by the Judith Butler position.
By linking sex to signification, Butler makes our sexuality something that communicates itself to others. While the fact that communication is a pro­cess, & thus ongoing, precludes a complete unfolding of knowledge
When, on the contrary, sex is disjoined from the signifier, it becomes that which does not communicate itself, that which marks the subject as unknow­ able. To say that the subject is sexed is to say that it is no longer possible to have any knowledge of him or her. Sex serves no other function than to limit reason, to remove the subject from the realm of possible experience or pure understanding. - Joan Copjec
Jujutsu With Zizek