Paul Tillich, A History Of Christian Thought
Augustine (continued)

We discussed the type of thought in epistemology, psychology, and doctrine of God represented by Augustine, which makes him the one representative of the possibilities of a philosophy of religion in which philosophy and the Christian message are brought together.

The statement I made was that after skepticism – in which Augustine himself participated in one period – had broken down the certainty of the external world, Augustine goes into himself and rediscovers the ultimate certainty within his own soul, not in terms of changing psychological terms, but in terms of something unconditional, which transcends all psychological phenomena. I said that this is not an argument for the existence of God, but the description of an element in man’s finitude which is always present, namely the element of the unconditional, of which he is aware.

There were people whom Augustine met who said: Why truth at all? Truth as such is not necessary. Why not stick to probabilities? Why not restrict oneself to pragmatic answers, answers which work? – But he says this is not sufficient, because it leads to a complete emptiness of life. Without something unconditional or ultimate, the preliminary meanings lose their meaning. And this cannot be replaced by another statement, namely that the human situation is not (one of ) having truth, but searching for truth. He says: Searching for truth, also, is not an answer to the question of truth because if we are searching for truth, then we must have at least some insight of truth, we must know, when we approach truth we, approach it. But in order to know that we approach truth, we must already have a criterion: truth itself. — What he says here is that in every relativism, however radical it may be, there is an absolute norm presupposed, even if it cannot be expressed in propositions. Since truth is something which we can find only in the interior of the human soul, physics are useless for ultimate truth. They do not contribute to the knowledge of God. He says: While the angels have knowledge of the Divine things, the lower demons recognize the world of the bodies — so a knowledge of the bodily world is a participation in the bodily world. Knowledge is union; union implies love; and he who deals cognitively with the bodies loves them, is connected with them, participates in them. That means he is distracted from the highest, the Divine, knowledge.