Everyone knows that a belief is true if it corresponds with the facts. This is the first theory of truth, and it has only two problems: what to make of correspondence, and what to make of facts. Facts, said the twentieth century logician Willard Van Orman Quine, are fictions: sentence-sized objects invented for the sake of correspondence. Facts are not simply given, independent, partners of true beliefs. To form a belief is just to claim to find a fact. It may or may not be a fact that Elizabeth I remained a virgin; to find out requires inquiry, and inquiry is just a matter of settling what to believe about this pressing issue.
Inquiry is a matter of warping our beliefs as little as possible in order to accommodate new experience. But in order to exert a pressure, experience needs to be interpreted and conceptualised, or in other words, to have a voice, indicating what to believe. So once it includes the results of inquiry, there is no escape from our overall system of belief. So says the second theory: the coherence theory of truth. It suggests a picture in which we are cut off from the world, imprisoned in a gossamer web of our own construction. Yet many fine philosophers have ended up here, and it gives us the second of our theories.
"The cure is for people to respect inquiry above assertion"
If abstract attempts to say what truth is all stumble, perhaps the remedy is to descend to particular cases. When Pilate asked “what is truth?” we could best have replied if only he had told us what in particular was bothering him. If his interest was in whether the defendant in front of him was disloyal to Caesar, well then, the truth would be the defendant in front of him being disloyal to Caesar, or not, and it was his job to settle that. Wondering whether it is true that it is raining is just the same thing as wondering whether it is raining. The equation iterates. As well as wondering whether it is true that it is raining you might wonder whether it is really true, or a fact that it is true, or true that it is a fact that it is true. But however far you continue, you are doing no more than wondering whether it is raining. If you settle that it is raining, then at a stroke you settle that it is true that it is a fact that it is really so that...it is raining. All these additions are nothing but ornaments: “it is true that” or “it is a fact that” add nothing. This is the key to the fourth theory, the deflationist theory of truth.
There are areas, such as ethics, politics, religion, and aesthetics where we are familiar with intractable disagreements. Some people think the same about the age of the earth or man-made climate change. The cure is for people to respect inquiry above assertion. Full, sober, objective, unbiased, inquiry is the only way forward, and it settles some things, if not everything. And the pragmatists were right about one thing: if you think knowledge is expensive, try ignorance.