Commentaria in Summam contra Gentiles, Liber III

After St. Thomas has shown that the rational creature falls under divine providence in a certain particular way, inasmuch as it is directed not only according to the suitability of the species, but also according to the suitability of the individual, he determines further concerning the very manner of divine governance regarding rational individuals, inasmuch as they are such¹.

Now, concerning this he does two things: first, he shows that it belongs to God to give laws to men; second, that it belongs to him to punish or reward men, ch. 140.

Concerning the first, he does two things: first, he shows that it was necessary that laws be given to men by God; second, he makes clear what the divine law aims at, in the following chapter.

I. As to the first, this conclusion is laid down: It was necessary that a law be given to man by God.

It is proved first thus. The acts of irrational creatures, insofar as they belong to the species, are directed by God by a certain natural inclination, which follows upon the nature of the species. Therefore, above this, something must be given to men by which they may be directed in their personal actions. But this we call law. Therefore, etc. — The consequence is proved: because just as the acts of irrational creatures are directed by God by reason of their belonging to the species, so human acts are directed by God according as they belong to the individual.

It must be noted that law, as is said in what follows, is nothing other than a rule and measure by which the acts of certain beings are directed and governed. Therefore in this place St. Thomas says that we call law that by which men are directed in their personal acts.

II. Secondly. The rational creature is so subject to divine providence that it also participates in a certain likeness of it, inasmuch as it can govern both itself in its own acts and other things. Therefore, etc. — The consequence is proved: because that by which the acts of certain beings are governed is called a law.

It must be noted that the efficacy of this argument consists in this: that, just as all things that are in the universe are governed by God by a certain law and rule, since divine providence itself is the law and rule of all things; so, since human acts are governed by man himself, who has a participated likeness of divine providence, it is necessary that man have from God some rule and law by which he may direct his acts, which law, namely, is a certain participation in divine providence.

III. Thirdly. It is fitting that a law be given only to those who know the rationale of their work. But this belongs to the rational creature alone. Therefore it was fitting that a law be given to it alone. — The major premise is proved: because law is a certain rationale and rule of operation.

2. Concerning the proof of the major, it must be considered, from the doctrine of St. Thomas, I-II, q. 90², that rationale in this place is taken for that which is constituted through the act of the intellect, in which way every concept produced through the act of the intellect, whether complex or incomplex, is called a rationale. That concept, therefore, which practical reason forms concerning actions to be performed, which concept is a certain universal proposition about things to be done, is called the rationale and rule of action: because according as the intellect determines that some action ought to be done, so it is to be performed. Therefore to say that law is the rationale and rule of operation is nothing other than that law is a conception of the practical intellect according to which operation is to be directed and regulated: just as also an artificial operation is regulated through the art existing in the mind of the artisan.

This argument, and that which immediately follows, proves not only that laws ought to be given to men, but also that among animals they are to be given to men alone.

IV. Fourthly. A law is to be given to those in whom it is to act and not to act. But this belongs to the rational creature alone. Therefore, etc.

It must be noted that the reason why a law is to be given only to those in whose power it is to act or not to act is that, as is said in I-II, in the place cited³, law is a certain rule and measure of acts, according to which one is induced to act, or restrained from acting. For toward those things to which one is induced from the necessity of nature, it is not necessary that one be induced through a law superadded to nature. And much less is it necessary that one be restrained from them through a law, since it is impossible that they not come about in the way that the necessity of nature demands. Hence also to brutes a law is not properly given, because they are driven to their actions by natural instinct. But toward those things which one is able to do and not to do, one can be induced so as to act, or also restrained lest one act. Therefore concerning these it is necessary that a law be given, so that through it the direction of free acts may be accomplished.

V. Fifthly. The rational creature attains its ultimate end in God and from God. Therefore, etc. — The consequence is proved: because each one capable of law receives the law from him by whom he is led to the end, just as a lower artisan receives it from the architect, and a soldier from the leader of an army. Now the reason for this is that the rationale of every work is taken from the end; but the law is the rationale of the work.

The conclusion is confirmed by the authority of Jeremiah 31 and Hosea 8.