Commentaria in Summam contra Gentiles, Liber I

I. In the second place, Saint Thomas compares the divine goodness to other goods with respect to its excellence¹, and shows that God is the highest good.

1. It is proved first. Divine goodness is compared to all goods as universal goodness to particular, since it is the good of every good. Therefore it preeminently surpasses every particular good. — The consequence is evident. For universal goodness surpasses particular goodness, just as the good of a nation is better than the good of one man, because the perfection of the whole surpasses the perfection of the part, speaking simply and absolutely.

II. Second. What is said through essence is said more truly than what is said through participation. God is called good through essence, and other things through participation. Therefore, etc.

Concerning that proposition, that which is said by essence is said more truly than what is said by participation, a doubt arises. For whiteness, which is said by essence, is not said to be white more truly than that which participates in whiteness. — Indeed, it is not even called white.

For the understanding of this, it must be considered that what is said to be something by essence can be compared both to what is such by a likeness which is its cause and to what is such by participation. If in the first way, since "more truly," as is found in Truth q. IV, a. 6, can designate either the truth of a thing or the truth of predication: if it designates the truth of a thing, then it is not necessary that something be more true where it is by essence. For it can be more true where it is by a likeness which is the cause of the thing than where it is by essence: just as natural things are more truly in the divine mind, where they are by an assimilative likeness, than in themselves, where they are by essence. By "more truly" in this way I understand the same as "more perfectly": for on the side of the thing, truth is founded in esse; and therefore to say that a thing is more truly in God according to the truth of the thing is to say that it has in him a more perfect esse than in itself; because the former is divine, while the latter is created. — But if it signifies the truth of predication, then in this sense each thing is more true where it is by essence than where it is by a likeness. For the truth of predication is considered according as something is said of another according to its formal signification. Now nothing can belong to something more formally than if it belongs to it by essence.

If in the second way, then, however the term more truly is taken, the proposition of St. Thomas is true. For what belongs to something through its essence has being in it more perfectly than in that to which it belongs through participation. And it has a greater formal identity with it itself: from which it follows that it is also predicated more truly.

By way of example, it is said that what is understood is the proposition of St. Thomas where that is predicated formally of both, and where the essence itself subsists per se. For then it is more truly said that it is the very quiddity than that it is what has a quiddity. And because God is goodness itself, while other things have goodness, and He is said to be good formally just as other things are said to be good: therefore He is also said to be good more truly and more perfectly. But whiteness does not admit the predication of its concrete term, so as properly to be called white; nor is it per se either, though it is signified per se. Therefore it is not similar.

III. Third. All things have the character of goodness from God. Therefore, etc. — The consequence is proved. Because that which is the cause of others in a single genus is the greatest in that genus.

Note that "genus" is here taken for every common thing according to the same ratio, either simply or proportionally, as was shown above².

Fourth. In God evil exists neither in act nor in potency. Therefore He is the highest good. — The consequence is proved. Because that which is less mixed with evil is better.

It is confirmed by the authority of 1 Kings 2.