Full Idea
To demonstrate the necessity of a truth-conditional theory of meaning, a proponent of such a theory must argue that use cannot be described without appeal to the conditions for the truth of statements.
Gist of Idea
Truth-condition theorists must argue use can only be described by appeal to conditions of truth
Source
Michael Dummett (Truth and the Past [2001], 1)
Book Reference
Dummett,Michael: 'Truth and the Past (Dewey Lectures)' [Columbia 2004], p.28
A Reaction
Unlike Dummett, I find that argument rather appealing. How do you decide the possible or appropriate use for a piece of language, if you don't already know what it means. Basing it all on social conventions means it could be meaningless ritual.