"Credo"...[m]eans that man does not regard seeing, hearing and touching as the totality of what concerns him, the he does not see the area of his world as marked off by what he can see and touch, but seeks a second mode of access to reality, a mode which he calls in fact belief, and in such a way that he finds in it the decisive enlargement of his whole view of the world.
If this is so, then the little word "Credo" contains a basic option vis-a-vis reality as such; it signifies not the observation of this or that fact but a fundamental mode of behaviour towards being, towards existence, towards one's own sector of reality and towards reality as a whole.
It signifies the deliberate view that what cannot be seen, what can in no wise move into the field of vision, is not unreal; that on the contrary what cannot be seen in fact represents true reality, the element that supports and makes possible all the rest of reality. And it signifies the view that this element which makes reality as a whole possible is also what grants man a truly human existence, what makes him possible as a human being existing in a human way.
In other worlds, belief signifies the decision that at the very core of human existence there is a point which cannot be nourished and supported on the visible and tangible, which encounters and comes into contact with what cannot be seen and finds that it is a necessity for its own existence.
Joseph Ratzinger, Introduction to Christianity, Herder and Herder, NY, 1970, p. 24.
