The paper highlights a certain kind of self-falsifying utterance, which I shall call antiperformative assertions, not noted in speech-act theory thus far. By taking such assertions into account, the old question whether explicit performatives have a truth-value can be resolved. I shall show that explicit performatives are in fact self-verifyingly true, but they are not related to propositions the way ordinary assertions are; antiperformatives have the same unusual relation to propositions, but are self-falsifyingly false. Explicit performatives are speech acts performed (...) in situations where it is important that the speaker is self-reflectively aware of what he is doing in the speech act. Antiperformatives, on the other hand, are speech acts performed in situations where lack of direct self-reflectiveness is required. In order to situate performatives and antiperformatives, the analysis is embedded within a more general discussion of self-falsifying and self-verifying assertions. (shrink)