What is law?

I say: Law is rightly defined: « An ordination of reason to the common good, promulgated by him who has the care of the community ¹ ». So commonly with the Author. It is explained. ¹ Here q. 90, a. 4, c.

It is said 1° an ordination of reason, namely practical: by which is understood the act of command or rather its term or dictate produced by it, by which the superior prescribes something to be done or omitted. It is also understood an efficacious ordination, indeed not with respect to the work prescribed, since laws are continually violated, but with respect to the obligation which affects subjects, by which it is distinguished from counsel. Likewise it is understood a firm, stable and perpetual ordination, in this sense that it does not cease through the death of the legislator, by which it is distinguished from a precept, nor is it borne to the present alone, but also to those to come, although it could cease absolutely either through revocation, or through change of the matter, or through cessation of the adequate end.

It is said 2° to the common good. For the end of law is the common good: both because law is borne for the community, so to speak, which it directs to a good and honest end, and that end is the good of the whole; and because the end ought to answer to the principle, but the principle of law is public authority. Therefore the end of law ought to be the public and common good. And by this are excluded the mandates of tyrants and others that would be made for proper and private advantage.

It is said 3° by him who has the care of the community: because law is borne for the whole community; for thus the common sense apprehends it, and herein it distinguishes law from precept, which regards one or another, and this is evident by induction. The natural law regards all men; the old law the whole Jewish people; the new law the whole human race; all human laws, both civil and ecclesiastical, are directed to communities. Therefore law must be from him who has the care of the community. Understand a perfect community, which is a multitude of men under the governance of a president having political jurisdiction.

It is said promulgated: because it cannot direct nor oblige unless it becomes known through promulgation. Whether promulgation is of the essence of law, I will say presently.

From what has been said you will infer that law is something of reason ¹, presupposing however an act of the will. The reason of the first part is 1° because, as was said, it is defined as an ordination of reason; 2° because it belongs to law to command and to direct, but imperium is essentially of reason, as we proved in dissert. III, on Human Acts, art. 4; 3° because law is a certain rule and measure of human acts, but the rule and measure of human acts is reason: whence in Psal. CXVIII divine judgments, words, utterances are called, all of which pertain to the intellect. The reason of the second part is, because law pertains to practical reason and consists in the act of command. But imperium, although elicited by the intellect, nevertheless supposes an act of the will, namely election, from which it has the power and efficacy of moving to exercise. Therefore. Confer dissert. cit. And this is the reason why in Scripture and in law law is sometimes set forth under the name of will. ¹ Ibid., a. 1, c.