I'm not the only Language Log contributor who's a fan of Rob Balder's wonderful PartiallyClips, a cartoon strip made by the very simple device of adding speech balloons to an uncopyrighted clip art picture repeated three times. This recent strip is about language and logic.
Rob's male character is wrong about paradoxes (looking up the right definition is left as an exercise for the reader); but he is right that sometimes the effect an utterer's speech activity has on the context can affect the possible truth values of a statement. I am now moving my lips, which contains four bilabial consonants, is another example: the moment you say it, it becomes true.
Not logically true, though; contingently true in virtue of a property that the context of utterance picks up because of what you are doing. It might be called (if you want a term for it) a contextual tautology.Posted by Geoffrey K. Pullum at August 6, 2005 08:46 PM