“Man can be compelled to do a good many things. There are a good many other things he can do in a halfhearted fashion, as it were, against his will. But belief can never be halfhearted. One can believe only if one wishes to. Perhap the credibility of a given person will be revealed to me so persuasively that I cannot help but think: It is wrong not to believe him; I “must” believe him. But this last step can be taken only in complete freedom, and that means that it can also not be taken. There may be plenty of compelling arguments for a man’s cedibility; but no argument can force us to believe him.
The unanimity of statements on this point is astonishing; and the agreement ranges all the way from Augustine and Thomas to Kierkegaard, Newman and Andre Gide. Augustine’s phrase from the Commentary on John is famous; “Nemo credit nisi volens”: No one believes except of his own free will. Kierkegaard says that one man can do much for another, “but give him belief, he cannot”. Newman is forever stressing, in one guise or another, the one idea that belief is something other than the result of a logical process; it is precisely not “a conclusion from premises”. “For directly you have a conviction that you ought to believe, reason has done its part, and what is wanted for faith is, not proof, but will.” And Andre Gide? In the last jottings he published after his Journals we may read these sentences: “There is more light in Christ’s words than in any other human word. This is not enough, it seems, to be a Christian: in addition, one must believe. Well, I do not believe.” Taken all together, these statements obviously mean the following: It is one thing to regard what someone else has said as interesting, clever, important, magnificent, the product of genius or absolutely “true”. We may feel compelled to to think and say any and all these things in utter sincerity. But it is quite a different matter to accept precisely the same statements in the way of belief. In order for this other matter, belief, to come about, a further step is necessary. A free assent of will must be performed. Belief rests upon volition” (Josef Pieper, Faith, Hope, Love, p 35-36).