History is full of men who have claimed that they came from God, or that they were gods, or that they bore messages from God–Buddha, Mohammed, Confucius, Christ, Lao-tze, and thousands of others, right down to the person who founded a new religion this very day. Each of them has a right to be heard and considered. But as a yardstick is external to and outside of whatever is to be measured and needed, so there must be some permanent tests available to all men, all civilizations, and all ages, by which they can decide whether any one of these claimants, or all of them, are justified in their claims. These tests are of two kinds: reason and history. Reason, because everyone has it, even those without faith: history, because everyone lives in it and should know something about it.
–Fulton Sheen, Life of Christ