In Chapter 1, I traced how Irigaray turns away from her early project of redefining and revaluing the symbolically female. I suggested that we can see, in An Ethics of Sexual Difference in particular, that Irigaray comes to believe that this earlier project presupposes a conceptual hierarchy which privileges (tacitly male) culture over (tacitly female) matter and nature, a presupposition which conflicts with the project's aim ofrevaluing matter and the female. Irigaray therefore reconceives sexual difference as primarily natural rather than symbolic, urging that social and political institutions be transformed to give expression and recognition to this natural difference. Her philosophy of natural sexual difference is fruitful in that it consistently undermines the culture/nature conceptual hierarchy and justifies a politics which aims, simultaneously, to end women's exploitation and the degradation of the natural environment. In view of this fruitfulness, I have suggested, Irigaray's philosophy of natural sexual difference merits further examination, despite its problems. Yet Irigaray's later philosophy would, after all, be undeserving of further examination should there exist an alternative feminist theory with the same conceptual and political attractions but no comparable problems. Arguably, this alternative exists in the guise of Judith Butler's theory of gender, which offers the most fully and coherently developed alternative to Irigaray's philosophy of sexual difference. No defence of Irigaray's philosophy can carry conviction, then, unless it proceeds by way of a reconstruction and assessment of Butler's theory of gender.