Summa contra Gentiles1.54 Chapter LIV. How the divine essence, though one and simple, is a proper likeness of all things intelligible

And yet it may seem to someone difficult or impossible that the one and same simple thing, such as God's essence, be the proper type or likeness of diverse things. For, since the distinction of diverse things arises from their proper forms, that which by reason of its proper form is like one of them must needs be unlike another. Whereas, so far as diverse things have something in common, nothing hinders them from having one likeness, for instance a man and an ass, in as much as they are animals. Hence it would follow that God has not proper but common knowledge of things: because the operation of knowledge follows according to the mode by which the thing known is in the knower, even as heating follows the mode of heat: for the likeness of the thing known in the knower is as the form by which a thing acts. Therefore if God has proper knowledge of many things it follows that He is Himself the proper type of each. How this may be, we must investigate.

As the Philosopher says (8 Metaph.) forms of things, and their definitions which signify them, are like numbers. For in numbers, if one unit be added or subtracted the species of the number is changed; as appears in the numbers and 4. Now it is the same with definitions: for the addition or subtraction of one difference changes the species: thus a sensible substance minus rational and plus rational differs specifically.

Now in things which include many, it is not the same with the intellect as with nature. For the nature of a thing does not allow of the separation of those things that are required essentially for that thing: thus the nature of an animal will not remain if the soul be taken away from the body. On the other hand the intellect is sometimes able to take separately those things which are essentially united, when one is not included in the notion of the other. Wherefore in the number it can consider the number alone, and in a rational animal it can consider that which is only sensible. Hence the intellect is able to consider that which includes several things as the proper notion of several, by apprehending one of them without the others. For it can consider 10 as the proper notion of 9, by subtracting one unit, and in like manner as the proper notion of each lesser number included therein. Again, in man, it can consider the proper type of an irrational animal as such, and of each of its species, unless they imply the addition of a positive difference. For this reason a certain philosopher, Clement by name, said that the things of higher rank are the types of those of lesser rank.

Now the divine essence contains the excellences of all beings, not indeed by way of composition, but by way of perfection, as we have shown above. And every form, whether proper or common, so far as it is something positive, is a perfection: nor does it include imperfection except in so far as it falls short of true being. Wherefore God's intellect can include within His essence that which is proper to each thing, by understanding wherein each thing imitates His essence, and wherein it falls short of His essence: for instance, by understanding His essence as imitable in respect of life and not of knowledge, it understands the proper form of a plant: or again as imitable in respect of knowledge but not of intellect, it understands the proper form of an animal, and so on. Hence it is clear 1 Cf. Dion., Div. Norn. v. 2 Ch. xxxi.

that the divine essence, in as much as it is absolutely perfect, may be taken as the proper type of such thing. Wherefore God can have proper knowledge of all things thereby.

Since, however, the proper notion of one thing is distinct from the proper notion of another, and since distinction is the principle of plurality; we must consider a certain distinction and plurality of understood notions in the divine intellect, in so far as that which is in the divine intellect is the proper notion of diverse things. Wherefore, since this is according as God understands the proper relation of similarity which each creature bears to Him, it follows that the types of things in the divine intellect are not many nor different, except in so far as God knows that things can be like Him in many and divers ways. In this sense Augustine says that God makes man after one type and a horse after another, and that the types of things are manifold in the divine mind. Wherein also the opinion of Plato holds good, in that he held the existence of ideas according to which all that exists in material things would be formed.