Faith does not feed on thin air but on facts. Its instinct is to root itself in truth, to earth itself in reality, and it is this which distinguishes faith from fantasy, the object of faith from a figment of imagination . . . . This is always the way. This type of doubt is silenced by facts, answered by truth and reassured by understanding . . . . Truth is the only sufficient answer faith can give doubt, for it is the truth of the matter, the facts of the case which give faith its solid foundation.50