Summa contra Gentiles2.24 Chapter XXIV. That God works according to his wisdom

From the foregoing it is clear that God produces His effects according to His wisdom.

For the will is moved to act by some kind of apprehension: since the apprehended good is the object of the will. Now God is a voluntary agent, as we have proved. Since, then, in God there is none but intellectual apprehension, and since He understands nothing except by understanding Himself, to understand Whom is to be wise, it follows that God works according to His wisdom.

Again. Every agent produces its like. Hence it follows that every agent works by that according to which it bears a likeness to its effect: thus fire heats according to the mode of its heat. Now in every voluntary agent, as such, the likeness to his effect is in respect of the apprehension of his intellect: for if the likeness to his effect were in a voluntary agent according only to the disposition of his nature, he would only produce one effect, since the natural reason of one is only one. Therefore every voluntary agent produces an effect according to the reason of his intellect. Now God works by His will, as already proved.' Therefore He brings things into being by the wisdom of His intellect.

Moreover. According to the Philosopher (i Metaph.y it belongs to a wise man to set things in order: because the ordering of things cannot be done except by the knowledge of the things ordered as to their relation and proportion both to one another and to something higher which is their end: since the mutual order of certain things is on account of their order to the end. Now knowledge of the mutual relations and proportions of certain things belongs only to one who has an intellect; while it belongs to wisdom to judge of certain things by the highest cause. Wherefore it follows that all ordering is done by the wisdom of an intelligent being. Thus in mechanics those who direct the order of buildings are called the wise men of the building craft. Now the things produced by God have a mutual order which is not casual, as it is the same always or for the most part. Hence it is evident that God brought things into being by ordering them. Therefore God brought things into being by His wisdom.

Further. Things that proceed from the will are either things that may be done, such as acts of virtue, which are the perfections of the doer: or they pass into outward matter and are things that can be made. Wherefore it is clear that created things proceed from God as made. Now the reason about things to be made is art, as the Philosopher says. Therefore all created things are compared to God as products of art to the craftsman. But the craftsman brings his handiwork into being by the ordering of his wisdom and intellect. Therefore God also made all creatures by the ordering of His intellect.

This is confirmed by divine authority: for it is said in the psalm: Thou hast made all things in wisdom, and (Prov. iii. 19): The Lord by wisdom hath founded the earth.

Hereby is set aside the error of some who said that all things depend on God's simple will without any reason.'