The Summa Contra Gentiles (Illustrated)

Accordingly, if the divine essence is distinct from its existence, it follows that His essence and existence are mutually related as potentiality and act. Now it has been proved that in God there is nothing of potentiality, and that He is pure act. Therefore God’s essence is not distinct from His existence.

the human intellect is incapable by its natural power of attaining to the comprehension of His essence: since our intellect’s knowledge, according to the mode of the present life, originates from the senses: so that things which are not objects of sense cannot be comprehended by the human intellect, except in so far as knowledge of them is gathered

For if movement had a beginning, it must have had its beginning from some mover. And if this mover had a beginning, it had its beginning from some agent. And thus either we shall go on to infinity, or we shall come to something without a beginning.

Nothing is at the same time in act and in potentiality in respect of the same thing. Now whatever is in motion, as such, is in potentiality, because motion is the act of that which is in potentiality, as such. Whereas whatever moves, as such, is in act, for nothing acts except in so far as it is in act. Therefore nothing is both mover and moved in

The first of these is proved by the Philosopher in three ways. First, thus. If a thing moves itself, it must needs have the principle of its movement in itself, else it would clearly be moved by another. Again it must be moved primarily, that is, it must be moved by reason of itself and not by reason of its part, as an animal is moved by the moveme

And the divine intellect surpasses the angelic intellect much more than the angelic surpasses the human. For the divine intellect by its capacity equals the divine essence, wherefore God perfectly understands of Himself what He is, and He knows all things that can be understood about Him: whereas the angel knows not what God is by his natural knowl

This, in a certain respect, is not in contradiction with the arguments of Aristotle; for it makes no difference whether with Plato we come to a first mover that moves itself, or with Aristotle to something first which is altogether immovable.

Again. Although that which is sometimes potential and sometimes actual, is in point of time potential before being actual, nevertheless actuality is simply before potentiality: because potentiality does not bring itself into actuality, but needs to be brought into actuality by something actual. Therefore whatever is in any way potential has somethi

Therefore if God, Who is the first cause, is the material cause of things, it follows that all things exist by chance. Further. Matter does not become the cause of an actual thing, except by being altered and changed.