3. God knows other things besides Himself by His essence, inasmuch as His essence is the type of other things that come forth from Him (Chap. LIV). But since the essence of God is infinitely perfect (Chap. XLIII), while of every other thing the being and perfection is limited, it is impossible for the whole sum of other things to equal the perfection of the divine essence. Therefore the representative power of that essence extends to many more things than the things that are. As then God knows entirely the power and perfection of His essence, His knowledge reaches not only to things that are, but also to things that are not.
6. The understanding of God has no succession, as neither has His being: it is all together, ever abiding, which is the essential notion of eternity, whereas the duration of time extends by succession of before and after. The proportion of eternity to the whole duration of time is as the proportion of an indivisible point to a continuous surface, -- not of that indivisible point which is a term of the surface, and is not in every part of its continuous extent: for to such a point an instant of time bears resemblance; but of that indivisible point which lies outside of the surface, and yet co-exists with every part or point of its continuous extent:* for since time does not run beyond motion, eternity, which is altogether beyond motion, is no function of time. Again, since the being of the eternal never fails, eternity is present to every time or instant of time. Some sort of example of this may be seen in a circle: for a point taken on the circumference does not coincide with every other point; but the centre, lying away from the circumference, is directly opposite to every point on the circumference.* Whatever therefore is in any portion of time, co-exists with the eternal, as present to it, although in respect to another portion of time it be past or future. But nothing can co-exist in presence with the eternal otherwise than with the whole of it, because it has no successive duration. Whatever therefore is done in the whole course of time, the divine mind beholds it as present throughout the whole of its eternity; and yet it cannot be said that what is done in a definite portion of time has always been an existing fact. The conclusion is that God has knowledge of things that in the course of time as yet are not.
By these reasons it appears that God has knowledge of nonentities. But all nonentities do not stand in the same regard to His knowledge. Things that neither are, nor shall be, nor have been, are known by God as possible to His power: hence He does not know them as being anywise in themselves, but only as being within the compass of divine power. These sort of things are said by some to be known by God with the 'knowledge of simple understanding' (notitia simplicis intelligentiae). But as for those things that are present, past, or future to us, God knows them as they are within the compass of His power; and as they are within the compass of their own several created causes; and as they are in themselves; and the knowledge of such things is called the 'knowledge of vision' (notitia visionis). For of the things that are not yet with us,* God sees not only the being that they have in their causes, but also the being that they have in themselves, inasmuch as His eternity is indivisibly present to all time. We must remember that God knows the being of everything through His own essence: for His essence is representable by many things that are not, nor ever shall be, nor ever have been. That same essence is the type of the power of every cause, in virtue of which power effects pre-exist in their causes. Again the being of everything, that it has in itself, is modelled upon the being of the divine essence. Thus then God knows nonentities inasmuch as in some way they have being, either in the power of God, or in their (creature) causes, or in themselves.* To this the authority of Holy Scripture also gives testimony: All things are known to the Lord our God before their creation; as also, after they are fully made, he regardeth all (Ecclus XXIII, 29): and, Before I formed thee in the womb, I knew thee (Jer. I, 5).
1.65 : That God knows Individual Things
1.67 : That God knows Individual Contingent Events