It remains to investigate the kind of knowledge in which the ultimate felicity of an intellectual substance consists. For there is a common and confused knowledge of God which is found in practically all men; this is due either to the fact that it is self-evident that God exists, just as other principles of demonstration are—a view held by some people, as we said in Book One —or, what seems indeed to be true, that man can immediately reach some sort of knowledge of God by natural reason. For, when men see that things in nature run according to a definite order, and that ordering does not occur without an orderer, they perceive in most cases that there is some orderer of the things that we sec. But who or what kind of being, or whether there is but one orderer of nature, is not yet grasped immediately in this general consideration, just as, when we see that a man is moved and performs other works, we perceive that there is present in him some cause of these operations which is not present in other things, and we call this cause the soul; yet we do not know at that point what the soul is, whether it is a body, or how it produces these operations which have been mentioned.
 Of course, it is not possible for this knowledge of God to suffice for felicity.
 In fact, the operation of the man enjoying felicity must be without defect. But this knowledge admits of a mixture of many errors. Some people have believed that there is no other orderer of worldly things than the celestial bodies, and so they said that the celestial bodies are gods. Other people pushed it farther, to the very elements and the things generated from them, thinking that motion and the natural functions which these elements have are not present in them as the effect of some other orderer, but that other things are ordered by them. Still other people, believing that human acts are not subject to any ordering, other than human, have said that men who order others are gods. And so, this knowledge of God is not enough for felicity.
 Again, felicity is the end of human acts. But human acts are not ordered to the aforementioned knowledge, as to an end. Rather, it is found in all men, almost at once, from their beginning. So, felicity does not consist in this knowledge of God.
 Besides, no man seems to be blameworthy because of the fact that he lacks felicity; in point of fact, those who lack it, but are tending toward it, are given praise. But the fact that a person lacks the aforesaid knowledge of God makes him appear very blameworthy. Indeed, a man’s dullness is chiefly indicated by this: he fails to perceive such evident signs of God, just as a person is judged to be dull who, while observing a man, does not grasp the fact that he has a soul. That is why it is said in the Psalms (13:1, 52:1): “The fool hath said in his heart: There is no God.” So, this is not the knowledge of God which suffices for felicity.
 Moreover, the knowledge that one has of a thing, only in a general way and not according to something proper to it, is very imperfect, just like the knowledge one might have of a man when one knows simply that he is moved. For this is the kind of knowledge whereby a thing is known only in potency, since proper attributes are potentially included within common ones. But felicity is a perfect operation, and man’s highest good ought to be based on what is actual and not simply on what is potential, for potency perfected by act has the essential character of the good. Therefore, the aforementioned knowledge is not enough for our felicity.
Next - CONTRA GENTILES - BOOK THREE: PROVIDENCE -Chapter 39 THAT HUMAN FELICITY DOES NOT CONSIST IN THE KNOWLEDGE OF GOD GAINED THROUGH DEMONSTRATION