Chapter 49 — That God knows things other than himself

From the fact that God knows himself first and essentially, we must conclude that he knows things other than himself in himself.

For the knowledge of an effect is sufficiently obtained from knowledge of the cause: therefore, we are said to know a thing when we know its cause. (Aristotle, Posterior Analytics 1.2, 71b9–11.) Now God by his essence is the cause of being in other things. Since, therefore, he knows his own essence most fully, we must conclude that he knows other things also.

Further. The likeness of every effect preexists somewhat in its cause, since every agent produces its like. Now whatever is in something else is in it according to the mode of the thing in which it is. If, therefore, God is the cause of certain things, since by his nature he is intellectual, the likeness of his effect will be in him intelligibly. Now that which is in a subject intelligibly is understood by it. Therefore, God understands things other than himself in himself.

Moreover. Whoever knows a thing perfectly knows whatever can be said truly of that thing, and whatever is becoming to it by its nature. Now it is becoming to God by his nature to be the cause of other things. Since, then, he knows himself perfectly, he knows that he is a cause, and this is impossible unless he knows his effect somewhat. Now this is something other than himself, for nothing is cause of itself. Therefore, God knows things other than himself.

Accordingly, taking these two conclusions together, (Cf. ch. 48.) it is evident that God knows himself as the first and essential object of his knowledge, and other things as seen in his essence.

This truth is explicitly declared by Dionysius as follows: he looks upon singulars not by casting his eye on each one, but he knows all things as one, contained in their cause; and further on: divine wisdom knows other things by knowing itself (On the Divine Names, 7).

Moreover, the authority of Sacred Scripture is seen to bear witness to the same statement. For in the Psalm it is said of God: he looked down from his holy height (Ps 102:19[101:20]), as though he saw other things from his exalted self.