In his book, An Introduction to Christianity, Joseph Ratzinger, who would later become Pope Benedict XVI, wrote:
However, vigorously [one] may assert that he is a pure positivist, who has long left behind him supernatural temptations and weaknesses, and now accepts only what is immediately certain, he will never be free of the secret uncertainty whether positivism really has the last word.
Just as the believer is choked by the salt water of doubt constantly washed into his mouth by the ocean of uncertainty, so the non-believer is troubled by doubts about his unbelief, about the real totality of the world which he has made up his mind to explain as a self-contained whole.
He can never be absolutely certain of the autonomy of what he has seen and interpreted as a whole; he remains threatened by the question whether belief is not after all the reality which it claims to be.
Just as the believer knows himself to be constantly threatened by unbelief, which he must experience as a continual temptation, so for the unbeliever faith remains a temptation and a threat to his apparently permanently closed world.
In short, there is no escape from the dilemma of being a man.
Anyone who makes up his mind to evade the uncertainty of belief will have to experience the uncertainty of unbelief, which can never finally eliminate for certain the possibility that belief may after all be the truth. It is not until belief is rejected that its unrejectability becomes evident.
It may be appropriate at this point to cite a Jewish story told by Martin Buber; it presents in concrete form the above-mentioned dilemma of being a man.
An adherent of the Enlightenment [writes Buber], a very learned man, who had heard of the Rabbi of Berditchev, paid a visit to him in order to argue, as was his custom, with him too and to shatter his old-fashioned proofs of the truth of his faith. When he entered the Rabbi’s room he found him walking up and down with a book in his hand, wrapped in thought.
The Rabbi paid no attention to the new arrival. Suddenly he stopped, looked at him fleetingly and said, “But perhaps it is true after all”.
The scholar tried in vain to collect himself – his knees trembled, so terrible was the Rabbi to behold and so terrible his simple utterance to hear.
But Rabbi Levi Jizchak now turned to face him and spoke quite calmly: “My son, the great scholars of the Torah with whom you have argued wasted their words on you; as you departed you laughed at them. They were unable to lay God and his Kingdom on the table before you, and nor can I.
But think, my son, perhaps it is true.” The exponent of the Enlightenment opposed him with all his strength; but this terrible “perhaps” which echoed back at him time after time broke his resistance.
Here we have, I believe – in however strange a guise – a very precise description of the situation of man confronted with the question of God. No one can lay God and is Kingdom on the table before another man; even the believer cannot do it for himself.
But however strongly unbelief may feel itself thereby justified it cannot forget the eerie feeling induced by the words “Yet perhaps it is true”. The “perhaps” is the unavoidable temptation which it cannot elude, the temptation in which it too, in the very act of rejection, has to experience the unrejectability of belief.
In other words, both the believer and the unbeliever share, each in his own way, doubt and belief, if they do not hide away from themselves and from the truth of their being.
Neither can quite escape either doubt or belief; for the one, faith is present against doubt, for the other through doubt and in the form of doubt. It is the basic pattern of man’s destiny only to be allowed to find the finality of his existence in this unceasing rivalry between doubt and belief, temptation and certainty.
Perhaps in precisely this way doubt, which saves both sides from being shut up in their own worlds, could become the avenue of communication. It prevents both from enjoying complete self-satisfaction; it opens up the believer to the doubter and the doubter to the believer; for one it is his share in the fate of the unbeliever, for the other the form in which belief remains nevertheless a challenge to him.
You should read my last post, What To Do With Doubt.