The theory of truth is a series of truisms.
Is it true or false that Belfast is north of London? That the galaxy is the shape of a fried egg? That Beethoven was a drunkard? That Wellington won the battle of Waterloo? There are various degrees and dimensions of success in making statements: the statements fit the facts always more or less loosely, in different ways on different occasions for different intents and purposes.
"What is truth?" said jesting Pilate, and would not stay for an answer. Pilate was in advance of his time. For "truth" itself is an abstract noun, a camel, that is, of a logical construction, which cannot get past the eye even of a grammarian. We approach it cap and categories in hand: we ask ourselves whether Truth is a substance (the Truth, the Body of Knowledge), or a quality (something like the colour red, inhering in truths), or a relation ("correspondence"). But philosophers should take something more nearly their own size to strain at. What needs discussing rather is the use, or certain uses, of the word "true." In vino, possibly, "veritas," but in a sober symposium "verum."
