Quotation by John Austin

To suppose that "I know" is a descriptive phrase, is only one example of the descriptive fallacy, so common in philosophy. Even if some language is now purely descriptive, language was not in origin so, and much of it is still not so. utterance of obvious ritual phrases, in the appropriate circumstances, is not describing the action we are doing, but doing it ("I do"): in other cases it functions, like tone and expression, or again like punctuation and mood, as an intimation that we are employing language in a special way ("I warn," "I ask," "I define"). Such phrases cannot, strictly, be lies, though they can "imply" lies, as "I promise" implies that I fully intend, which may be true.