Number of Americans who believe in God is at its lowest since at least 1944

What about historical truth? What about the truth of the state of another person’s mind? Neither of these can be tested in an empirical sense, but I don’t think we’d want to say that we can’t talk about “truth” in either context – our political discussions and legal proceedings rely on both these things, after all. You sound like an old-fashioned logical positivist.