Treatise II: On Laws

St. Thomas, 1.2, q. 90-108; St. Alphonsus, I, n. 90 ff.; ed. G., I, p. 70; Suarez, de Legibus, l. I, c. 1-4; Gonet, Clypeus Theol. Thom., tr. 13, p. 13; Zigliara, Ethica, n. 17, II; D'Annibale, I, n. 160; Kuhlmann, O.P., Der Gesetzesbegriff vom hl. Thomas (Bonn, 1912).

109. DEFINITION. Law (from binding), taken in the broader sense, is a rule according to which something ought to be done.

But moral law, which directs the free actions of man, is more precisely defined by the Angelic Doctor: An ordination of reason for the common good, promulgated by him who has care of the community (1.2, q. 90, a. 4).

It is called 1. an ordination, that is, a prescription or command, which strictly obliges. In this matter it differs from COUNSEL, in which there is only directive and suasive force. Therefore obligation pertains to the essence of law, or that moral necessity by which free will is bound to doing or omitting something.

2. of reason. For an ordination or precept, although it proceeds from the will of the Superior, nevertheless essentially requires also a judgment of the intellect, by which judgment the will, in prescribing, is rightly directed. Indeed no law can consist unless it is consonant with reason. Hence, in relation to the legislator, law is right reason of commanding; but in relation to subjects it is "right reason concerning things to be done" (H. Ap., II, 1).

3. for the common good. For the end of law is good, not indeed the private good of the Superior or of the subjects, but the common or public good of society. For it is contrary to right reason that the whole society be ordered to the advantage of one or only some, and that the whole be referred to the part.

For the rest, while each one procures the common good, he necessarily also consults his own proper good, at least spiritual; for the intention of the legislator (as St. Thomas teaches with Aristotle) is to make the subjects good (Contr. Gent., l. 3, c. 115, n. 3).

4. by him who has care of the community. For the faculty of making laws stands with him to whom the preservation and governance of the community pertains. Now by the name of community we understand a perfect community, namely one capable of political government, such as the Church, a kingdom, or a province of its own right. For, in order to make a law, domestic or dominative power is not sufficient, as Suarez says (l. I, c. 9, n. 4), such as men enjoy over a wife, a father over children, a master over servants (which power grants only the right of imposing precepts); but that public power of governing and coercing is necessary which is designated by the name jurisdiction (cf. n. 138).

5. promulgated. For promulgation pertains to the essence of any law which has the force of obliging, as St. Alphonsus (l. c.) demonstrates at length from St. Thomas. And the principal reason is that since law is a rule to which the community must conform itself, it must be proposed in such a way that it becomes known at least to the greater part of the community (cf. n. 158).

110. From these things you will gather: 1. LAW differs from a simple PRECEPT or mandate: a) by reason of the one commanding, because the legislator is a public person, but one prescribing can be a private man, possessing domestic power; b) by reason of the subject, because law is imposed on the community as such, and on individuals insofar as they are parts of the community; but a precept is imposed on private persons; c) by reason of the end, because law proximately and primarily regards the common good, but a precept the private good; d) by reason of extension; for since law is made for the community as such, if the community is contained in a certain place, law does not oblige outside this place. The contrary is had in a precept, which, because it affects the person, accompanies him wherever he goes, and, as they say, clings to his bones; e) by reason of stability; for a precept is transitory, and expires by the death or removal of the one commanding, unless the matter is no longer intact, or unless the precept concerns privileged causes, as pious causes are in Roman law. But law, by its nature, is perpetual: for it is established for the favor of the community which, as such, is not subject to death (I, 140; Reuter, P. I, n. 127; D'Annibale, I, n. 248).

111. 2. In order that a law (precept) oblige, it is required: a) on the part of the MATTER: alpha) that it be honest, that is, conformable to right reason and not contrary to divine law; beta) just, that is, that it proceed from legitimate power, not injure the rights of subjects, nor impose disproportionate burdens; gamma) morally possible, that is, that, for the circumstances of places and times, it not be too difficult to observe; delta) useful, that is, that it truly and notably conduce to the public good; b) on the part of the FORM, it is required that it be: alpha) manifest or clear; beta) promulgated, as we have already noted (n. 109). These things will be explained more fully below (n. 154).

Note. A precept can be imposed both by force of dominative power and by force of jurisdiction (cf. n. 14). In the first case, the transgressor sins against obedience alone, because the Superior, using such power, merely intends the subjection of the subject. In the second case, he ordinarily sins against only the virtue whose good is injured, because jurisdiction is an authoritative means for procuring the good of virtue.

112. DIVISION. Law is distinguished: 1. By reason of the object, into affirmative, which commands that an act be placed, and negative, which orders that an act be omitted. They differ between themselves in that affirmative law indeed obliges always, but not for always; but negative law obliges always and for always. And the reason is that, at any time whatever, we are bound to abstain from every evil, not however to do every good.

2. By reason of the legislator, into natural and positive. Natural law is that which becomes known to man from the very light of reason. To this belong, if you except the circumstance of the Sabbath (or Sunday), all the precepts of the Decalogue. Positive law, which is subdivided into divine and human, is that which proceeds from the free will of God or of men, and depends on it; for example, the law concerning Baptism, concerning the Lenten fast, etc.

This indeed is not dictated by nature, but is conformable to the law of nature, and especially differs from it in this: that those things which are prohibited by natural law are therefore prohibited because they are evil; but those things which are prohibited by merely positive law are therefore evil because they are prohibited (I, 101).

And these are the principal divisions of law (cf. n. 113 and 136). But since the formal notion of law comes in the first place from the legislator, hence it is why, according to the diversity of the legislator, namely divine or human, we judge that the present Treatise must be divided into two Dissertations, in one of which there will be treated OF DIVINE LAW, but in the other OF HUMAN LAW.