Term introduced by J. L. Austin in his book How to Do Things with Words, for an utterance by the making of which some further act is performed. The central examples are ‘I promise…’ or ‘I agree…’, whose saying constitutes promising or agreeing. Such utterances do not describe antecedent states of having made a promise or agreement, but bring it about that one has promised or agreed. The phenomenon had previously been recognized by Hobbes.