Philosophy has to grant that revelation is possible. But to grant that revelation is possible means to grant that philosophy is perhaps something infinitely unimportant. To grant that revelation is possible means to grant that the philosophic life is not necessarily, not evidently, the right life. Philosophy, the life devoted to the quest for evident knowledge available to man as man, would itself rest on an unevident, arbitrary, or blind decision. This would merely confirm the thesis of faith, that there is no possibility of consistency, of a consistent and thoroughly sincere life, without belief in revelation. The mere fact that philosophy and revelation cannot refute each other would constitute the refutation of philosophy by revelation.

p. 75 - Natural Right and History (1953)