Before there can be any profitable discussion of religious belief, therefore, we need to see that faith is one of the chief ways in which continually we deal with reality; it is a road to truth, without which some truth never can be reached at all. The reason for its inevitableness in life is not our lack of knowledge, but rather that faith is as indispensable as logical demonstration in any real knowing of the world. Behind all other words to be said about our subject lies this fundamental matter: _faith is not a substitute for truth, but a pathway to truth; there are realities which without it never can be known_. For one thing, no one can know _persons_ without faith. The world of people, without whom if a man could live, he would be, as Aristotle said, either a brute or a god, is closed in its inner meaning to a faithless mind. Entrance into another life with insight and understanding is always a venture of trust. We cry vainly like Cassim before the magic cave, "Open, Barley," if we try to penetrate the secrets of a human personality without sympathy, loyalty, faith. These alone cry "Open, Sesame." Surely this knowledge of persons, impossible without faith, is as important as any which we possess. While the physical universe furnishes the general background of our existence, the immediate world in which we really live is personal, made up of people whom we fear or love, by whom we are cheered, admonished, hurt, and comforted. "The world is so waste and empty," cried Goethe, "when we figure but towns and hills and rivers in it, but to know that someone is living on it with us, even in silence--this makes our earthly ball a peopled garden." A solitary Robinson Crusoe would give up any other knowledge, if in return he could know even a benighted savage like Friday. But even a savage cannot be known by logical demonstration. Crusoe could so have learned some things, but when he wanted to know Friday, he came by way of adventures in confidence, personal trust and self-commitment, growing reliance and appreciative insight, assured loyalty and faith. He _knew_ whom he had _believed_.