Article II: On Natural Law

— I. Notion. 1. Natural law is "nothing other than the participation of eternal law in the rational creature" ¹. Participation is had through the light of natural reason, by which man knows that the things which God has ordered have been imposed upon him, and, according to that primary ordering, he can also provide for himself and others through secondary orderings. But natural reason, of itself, can know only the order proportioned to human nature. Wherefore natural law is circumscribed by that part of eternal law which places an order congruent with non-elevated nature, and therefore an order hypothetically, that is, supposing creation, necessary: it cannot reach the higher order, which contains and perfects the former.

2. Natural law founds every other law: not only human law, because the principle of obliging cannot be in man ², but also positive divine law. That I may be held by this, it is necessary that, in my nature, I first have read the dominion by which God possesses me and has my will subject to Himself.

¹ St. Th. 1, 2, q. 91 art. 2, c.

² St. Th. 1, 2, q. 93 art. 3.

— II. Promulgation. Natural law, since it is the very order of nature, has been promulgated in human nature itself. Wherefore, although in the present condition of the human race it can have obscure parts, even according to those parts it obliges us all in first act, and ignorance of them only brings excuse to the person obligated of himself.

That is, contrary to what Lehmkuhl thinks, cf. I, 177, it has been promulgated whole. For by whatever way I know that some such thing is required by the natural order, already I read it in my nature, or in the authentic instrument of promulgation. From the beginning it is wholly in us habitually ¹. We think it must be denied that there are parts strictly impervious to the human intellect: these would not pertain to natural law. But if, with respect to the parts which are now obscure to us and for which revelation is morally necessary for us, natural law had to be called not promulgated, those parts, after revelation, would pertain to positive divine right and not to natural right: which no one will admit.

¹ Cf. St. Th. 1, 2, q. 91 art. 1 ad 3, and the response to the contrary.

— III. Divulgation. In the present condition of the human race, divine revelation is morally necessary so that natural law can be known sufficiently expeditiously, sufficiently certainly, sufficiently fully, and sufficiently generally. But the revelation by which that sufficient knowledge was given is now at the same time or identically revelation made for a supernatural end.

But even after revelation, if many things are plain to all, many others must be learned by the less instructed from the more learned, and many remain long controverted and doubtful even to the learned themselves.

Concerning those natural duties which of themselves are known to all, both these things are usefully noted.

1. Besides certain things which are so proximate to the first principles that they cannot be unknown, there are not a few conclusions, even not so remote from the first principles, which, at least outside the matter of justice, by accident are unknown by many for some time; and this ignorance can also, because of depraved customs, be increased, so that, for example, simple fornication is everywhere not held to be illicit. Cf. St. Th., 1, 2, q. 94 art. 4 c. and art. 6.

2. But the things which are known by all become known not only from a higher principle to which they can be reduced ², but also are perceived in themselves by direct intuition. Hence it happens that, concerning many things which are not doubted, the demonstration can be laborious and controverted: for example, concerning the grave malice of every voluntary pollution, concerning the duty of gratitude.

² St. Th. 1, 2, q. 94 art. 2.

— IV. Firmness. Nothing prevents many things from being added to natural law. But from it nothing can be subtracted. Wherefore the things which are imposed by natural law are immutable. But the matter of certain precepts can be placed, some in human power, some in divine power.

By the use of such power, it sometimes happens that, in fewer cases, a precept seems to cease negatively or even contrariwise.

Thus the common destination of material things brings it about that public power, for just causes, can transfer dominion from one person to another, and that things need not be returned to an owner who asks for them unreasonably. In these cases, the duty of returning the thing to the owner will not press; indeed it can be impeded by a stronger duty. God Himself, not as legislator but as lord, can bring it about that the note of homicide or of fornication is absent from a certain killing or from a certain intercourse, 1, 2, q. 94 art. 4, c.; art. 5, c.

But those apparent changes or exceptions furnish us no reason why, by our private authority as men, we should restrict the absolute dictates of natural law when it is a question of matter which is withdrawn from our power, such as, for example, the human person. Thus it will never be lawful, by private authority, to kill a man.

Nor, in the same matters, can cessation of the end on account of which, for example, pollution and fornication are prohibited, be alleged so that someone may think himself immune from the order to be observed. For we are subject not to the end alone but, and indeed most of all, to the very order established on account of the end. We find the title of our obligation less in the end, which can accidentally fail, than in the nature whose order is inviolable for the individuals who participate in that nature. That is, God does not command human nature through individual men, so that the immediate obligation of individuals would produce the obligation of nature, but He commands individuals through nature. To remain in the examples adduced, the precept is not only: "take care that men be duly multiplied, that offspring be prudently educated," but it is especially: "preserve the order of nature, which has been constituted for that purpose." Besides, since we bear in ourselves, toward the natural end, an intrinsic disposition or ordering, one already begins to act against the end who disturbs that disposition in himself by violation of that order, so that, whatever may happen, there is nevertheless already sin against the end of nature. Finally, the end which in some case seems to cease is not the adequate end, but generally is already seen by human reason itself to be only partial. And who are we to assign an adequate end to the work of God?

Thus, when St. Thomas demonstrates that fornication is a grave sin from the fact that it is against the good of offspring, the holy Doctor neither is ignorant of nor intends to deny the many other evils which extra-marital intercourse carries with it.

That conclusion is confirmed by the dangers of delusion. The most approved theologians agree in it, especially those of the golden age of the scholastics of the Middle Ages, who therefore, in demonstrating the grave and absolute obligations of natural duties, did not experience that difficulty which has made even excellent theologians of our age more or less hesitant.

For this reason, concerning natural law itself, St. Thomas could write: "that which falls under the determination of law is judged according to what commonly happens, and not according to what can happen in some case" (2, 2, q. 154, art. 2).

Kant also confirms this in his own way, when he proposes this perpetual rule of acting as necessary: "Act so that your action can be regarded as a universal norm." (Krit. der praktischen Vernunft, 1 T., 1 B., 1 Haupts., § 7.)

— V. What things are contained in natural law. All the precepts of natural law are founded in that highest natural precept of which there is no ignorance: "Good is to be done, and evil avoided." That is, by natural law all those things are prescribed to be done and avoided which reason naturally apprehends to be determinately human goods or evils ¹.

Those precepts themselves can be variously distributed or set forth in a logical order.

Thus, taking man as a creature redeemed by Christ, we see that man, insofar as he is a creature, ought to do those things which glorify God; but insofar as he is redeemed by Christ, that his actions ought to redound to the glory of Christ. Then, in natural inclinations, according as they are regulated by reason, we detect that there pertain to natural law those things which regard the proper preservation of man, the propagation of the human race and the due education of offspring, higher truth and social life: which are the inclinations of man as he is a substance desiring its nature, as he is an animal, and as he is a rational animal. For those things to which we incline are at the same time an end and a good, since the aspect of good is in the end. Cf. St. Thomas, 1, 2, q. 94 art. 2.

The same precepts can also be proposed as certain corollaries of principles or of more general precepts. Thus from the precepts of the Decalogue many other precepts are gathered.

There are also postulates required by the end for which the law itself was constituted. Thus we are taught by the very end of every law, which is that we have charity with God and with other men, that we must act in a spirit of charity ².

It also appears that the order of nature is composed of these three orders: the order which man must preserve toward God; the order which he must maintain toward neighbor; and the order which he must care for in himself. And the various precepts which are customarily recited are referred to these principles and are illustrated by these principles.

Hence the order of nature is shown to be entirely essential, insofar as it rests upon essences themselves, and at the same time it is nevertheless understood how it has less substantial parts. Thus, to the integrity of man in himself there pertain certain particular orders without which, nevertheless, man is seen to remain substantially ordered in himself. Cf. what is to be said concerning mortal and venial sin.

¹ St. Thomas, 1, 2, q. 94 art. 2.

² 1, 2, q. 99 art. 1 ad 2.

— VI. Subject of natural law. Every man is subject to natural law. Wherefore, although children and the perpetually insane cannot formally sin, they can commit material sins; and human nature can be violated by others in them. Wherefore they are to be blamed who are the cause why shameful things are done by children; and while they abuse childish simplicity, they commit a certain kind of stuprum.

— VII. Sanction of natural law. "Wherever there is some due order to an end, it is necessary that that order lead to the end, but withdrawal from the order excludes the end ¹." Lehmkuhl, I, 279, confirms the same in these words: "The divine will left freedom to rational creatures, here we take man, in such a way that, according as they were freely to conform themselves to the divine will or to resist it, they would consult their own happiness or misery." And indeed, eternal law, of which natural law is a participation, in its concept denotes the ordering by which God recalls all things to Himself, and at the same time brings creatures to their proper perfection. Therefore, by whatever reason or proportion the free creature withdraws from that order, by the same he virtually chooses withdrawal from his own perfection or good and beatitude, and from God. And opposition of contrariety brings aversion both from God and from one's own perfection or beatitude. And since the natural end is contained eminently in the supernatural end, in whatever manner one withdraws from the natural end, in the same manner one withdraws from the supernatural. Therefore, in this connatural sanction of natural law, we detect a certain immediate indication or explanation of mortal and venial sin, concerning which later; and already we understand in what way sinful man himself is the maker of his own ruin. Cf. St. Th., c. Gentiles, book 3, cap. 140 and following.

Therefore by its very essence, natural law in its entirety is moral. And because that law imposes the whole order of reason, that whole order also must be said to be sanctioned by natural law.

This also must be observed concerning the sanction of divine law. That sanction must be perfect, insofar as it is proportioned to every force and difficulty of the precept, so that it can never be truly useful or blessed for man to withdraw from that law; but there is no need that in fact it obtain an almost universal observance of the law. The reason is that, whether men observe or violate the divine law, the primary end of that law, the external glory of God, will in no way be frustrated. Human laws, on the contrary, must be practically efficacious, lest they be useless.

¹ Summa contra Gentiles, III, 140.