Term introduced by J. L. Austin, in his book How to Do Things with Words, for an act done in uttering what one does. Thus in saying ‘I promise’ in suitable circumstances I make a promise; in saying ‘Hooray!’ I cheer you on, and so forth. The illocutionary act is distinguished from anything effected by the utterance (its perlocutionary force): it makes no difference to the fact that I promised or cheered whether you believe my promise or are heartened at my cheering. Austin alerted philosophers to the possibility that certain terms might be treated illocutionarily. For example, in saying ‘I know that p’ I give you my word that p. It may well be that this insight sheds a different light on the traditional problems of defining knowledge, which assume that knowledge is a special state, described by one who says truly that she knows that p. See also speech acts.