One argues from ignorance, always. Argh.
In a real sense, Lacan's discourse is self-parodic. When Lacan says, "elles ne savent pas ce qu'elles disent, c'est toute la difference entre elles et moi," ["they don't know what they are saying, that's the whole difference between them and me"] (Encore 68), it must be remembered that for Lacan knowledge, le savoir, is itself constituted within the phallic order of the symbolic, that realm of ordered rationality and noncontradiction that psychoanalysis, both in spite of and because of its own scientific pretensions, must always see as a mystified realm of rationalization and one whose protocols Lacan's own discursive practice violates at every turn.From here. This actually does make sense within its own context, but still. The high-flown 80's: good times, good times.
Lacan ... sees the knowledge (savoir) involved in symbolic processes as indissociable from the knowledge (connaissance) produced in the early imaginary demarcations of 'psyche' and 'body,' a connaissance that is, in turn, activated differently in the symbolic depending on whether the subject is sexed through language as male or female. If anything, Lacan sees women as knowing they don't know what they're saying--by virtue of their position in the symbolic order--while men are dupes of Truth. (Weed 1994: 89)
Women don't "know" what they are saying because the feminine position within the phallic economy is located outside the symbolic, but it is only within the symbolic that "knowledge" defined as information processed in accord with the formal dictates of reason (i.e., the laws of symbolic substitution recognized by a given community) can occur. Lacan, Irigaray, and indeed Kristeva and Cixous agree that woman is not representable within the phallic order of the symbolic. (5) It is for this reason that Lacan argues that "La femme" does not exist, since the article "la" implies a universal and the concept of universality is the logical category that constitutes the very heart of the symbolic order. (6) Woman thus represents a hole in the symbolic, not because she is lacking (although that is the only way the patriarchal symbolic can represent her) but because she is exorbitant in relation to its totalizing claims.