 Judith Butler critiques the sex/gender distinction on two grounds. She critiques gender realism with her normativity argument (1999 [original 1990], chapter 1); she also holds that the sex/gender distinction is unintelligible (this will be discussed in section 3.3.). Butler’s normativity argument is not straightforwardly directed at the metaphysical perspective of gender realism, but rather at its political counterpart: identity politics. This is a form of political mobilization based on membership in some group (e.g. racial, ethnic, cultural, gender) and group membership is thought to be delimited by some common experiences, conditions or features that define the group (Heyes 2000, 58; see also the entry on  Identity Politics).  Feminist identity politics, then, presupposes gender realism in that feminist politics is said to be mobilized around women as a group (or category) where membership in this group is fixed by some condition, experience or feature that women supposedly share and that defines their gender.