 More nomenclature: ‘Speech act’ and ‘illocution’ will here be used synonymously. The latter term is due to Austin, who used ‘illocutionary force’ to refer to a dimension of communicative acts. (It is nowadays common also to use ‘illocute’ as a verb meaning ‘to perform a speech act.’) Austin’s reason for using ‘force’ begins with the observation that, construed as a bit of observable behavior, the communicative significance of an act may be underdetermined by what has been said or observably done. I bow deeply before you. So far you may not know whether I am paying obeisance, responding to indigestion, or looking for a wayward contact lens. So too, an utterance of a meaningful sentence (which Austin calls a locutionary act) such as ‘You’ll be more punctual in the future,’ may leave you wondering whether I am making a prediction or issuing a command or even a threat. The colloquial question, “What is the force of those words?” is often used to elicit an answer. In asking such a question we acknowledge a grasp of those words’ meaning but seek to know how that meaning is to be taken–as a threat, as a prediction, or as a command.