ABSTRACT. Having discussed some examples of anti-essentialism in Sartre and Rorty, the paper presents a general argument for essentialism based on the self-stultifying character of the anti-essentialist thesis (AET). It is concluded that the proponent of anti-essentialism is caught in an existential or performative contradiction, a contradiction between the content of what is being asserted in the AET and what the anti-essentialist is implicitly committed to in making that assertion.