Transsexuality has been subject to careful reflections in many disciplines outside philosophy. I first contextualize my philosophical approach by relating to the existing scholarship on transsexuality. Focusing on matters of sexual identity, I then propose a characterization of what might be considered the philosophical dimension of transsexual identity. Paying particular attention to the propositional consciousness of transsexuals, I develop the main thesis that transsexuality helps philosophers of sex to forcefully establish the contingency of sexual identity in terms of the underlying (...) biology of the sexed human body. I eventually argue that sexual identity is a cluster concept, which is constituted by sex, gender, sexual practice and desire. In this sense the following argument against “foundationalism” in philosophy of sex emerges: none of the four aspects of sexual identity can function as basic, prior to any normative commitments regarding the nature of human sexuality. (shrink)