But the animal only wills. without purpose – in the sense in which we ascribe it to man. Therefore for Thomas the intellect is that which makes man man and therefore is the primary characteristic of God.

Intellect is the insight into the universally true and good. But Duns Scotus opposed this doctrine. In him God and man are will. Will is universally creative. There is no reason for the Divine will other than the Divine will itself. There is nothing which determines the will. The good is good because God wills that it is. There is no intellectual necessity that the world is as it is, that salvation is as it is. Everything is possible for God except not to be God – that’s impossible for Him. This is what Duns Scotus called His potentia absoluta . the absolute power of God. But God uses His absolute power only in order to create a given world in which there are definite orders. Therefore he called this potestas ordinatus. the ordered power of God. Here he distinguishes these two: the world as we know it. and the purpose of salvation as we know it by revelation. is not necessarily so as it is. but now. after it has been given. it is so as it is; it is by Divine ordered power. But behind this stands something as a threat. The world is not as it is from eternity. There is no real necessity that it is as it is. The threatening absolute power of God behind the ordered power may change everything. Duns Scotus didn’t believe that this would happen. but it can happen.

Now what does such an idea mean? It means that we have to accept the given, that we cannot deduce it. that we have to be humble toward reality. We cannot deduce the world or the process of salvation in terms of, for instance. with Anselm’s doctrine of atonement. where he tried to deduce in terms of necessity the way of salvation between God and Christ. and man. Duns Scotus would say there is no such necessity; this is a positive order of God. Now here in this idea of the absolute power of God. we have the root of all positivism. in science as well as in politics. in religion as well as in psychology. In the moment in which God became “will”. who is only determined by Himself and His own will, and not by the intellect – in this moment the world became incalculable, uncertain, unsafe, and we are demanded to subject ourselves to what is given. All the dangers of positivism are rooted in this concept of Duns Scotus. And so I consider him, more than anybody else, the turning point in the history of Western thought.
Paul Tillich, A History Of Christian Thought – Table of Contents