This essay focuses on an issue arising from within an anti-essentialist perspective on sexual identity: how is it possible to explain the political impetus inhering in a category such as ?woman? without having recourse to a set of positive properties that would somehow ?x her identity in advance? I examine how a particular theoretical outlook, social postmodernism, attempts to address this issue, and argue that, ultimately, social postmodernism generates its own impasse which I call social foundationalism ? an impasse which is structurally similar to biological foundationalism. I invoke discourse-theoretic concepts to introduce the psychoanalytic categories of master signi?er and symbolic identi?cation. This is done in order to suggest how ...