Article II. On the Divine Natural Law

151. 1. Notion. The essence of the natural law is not explained in the same way by diverse authors. Some say that the natural law is rational nature itself, insofar as certain acts agree or disagree with it. Others assert that the natural law is a natural habit, by which each man knows the duties imposed upon him according to nature. Others think that the natural law is the actual dictate of natural reason. Others finally say that the natural law is the eternal law itself, and therefore they apply indiscriminately to both eternal and natural law the Augustinian definition given in the preceding article. Leaving aside all these opinions, which there is no time to refute one by one,¹⁶ we say with St. Thomas:¹⁷ "The natural law is nothing other than the participation of the eternal law in a rational creature." But we speak only of the moral natural law, not of the physical natural law, as we have already noted above.

It is explained: From eternity God knows and orders whatever is consonant with rational nature; and this ordinance existing in the divine mind is called the eternal law. But in time God created the human race and implanted in it this His ordinance conceived from eternity. Therefore as soon as man is born, he is also subject to this natural law. This participation of the eternal law, or moral order constituted by God, is the natural law considered objectively. But when man attains the use of reason, he knows at least the first principles of the natural law, for example, good is to be done and moral evil is to be avoided. And he not only knows that this law exists, just as, for example, someone knows the existence of the ancient Roman law, but he also intimately perceives that this natural law is strictly imposed upon him. This participation of the eternal law is the natural law considered subjectively.

This law is called natural for a twofold reason: 1. Because it includes only precepts which are deduced from the very nature of man. In this way it is distinguished from all other laws and notably from positive divine law, which contains precepts obliging from the divine will alone, for example, the obligation of receiving the sacraments. Sometimes, however, positive divine law for greater inculcation still expressly commands those things which have already been established by the natural law, for example, the precepts of the Decalogue. It is also distinguished from the eternal law, since this extends more broadly, containing besides the supernatural order. - 2. Because the natural law is known, or at least can be known, from the light of natural reason alone, without divine revelation or human magisterium being required. Nevertheless, with divine revelation or human magisterium acceding, the natural law is known more easily and more clearly, as is plain of itself.

¹⁶ See these refutations in Billuart, De leg. diss. 2, a. 2.

¹⁷ S. theol. I-II, q. 91, a. 2. In German: Das Naturgesetz ist die Ausstrahlung oder der Abglanz des ewigen Gesetzes in den vernünftigen Geschöpfen. In French: La loi naturelle est le reflet de la loi éternelle dans la créature raisonnable.

152. 2. Existence of the Natural Law is denied not only by Atheists, Materialists, Pantheists, etc., but also by all those who do not admit the supreme objective norm of morality;¹⁸ especially also by followers of the so-called "Historical School,"¹⁹ who admit no other law properly so called except positive law. According to these authors the state is the supreme legislatrix, and without it no law induces juridical obligation. Against all these the existence of the natural law is easily proved:

1. From Sacred Scripture. St. Paul²⁰ says: "For when the gentiles, who have not the [Mosaic] law, do by nature (φύσει) those things that are of the law, these, not having the law, are a law to themselves: Who show the work of the law written in their hearts, their conscience bearing witness to them, and their thoughts between themselves accusing or also defending, in the day when God shall judge the hidden things of men, according to my Gospel, through Jesus Christ." - From these words the following clearly appear: a) that the gentiles, who lacked the Mosaic law, nevertheless knew and observed certain precepts of the natural law; b) that this law is inscribed on the heart of every man; c) that on the day of judgment God will judge men according to this law. - Leo XIII²¹ expresses similar things in these words: "Such is the first of all laws, the natural law, which is written and engraved in the souls of individual men, because it is human reason itself commanding right action and forbidding sin."

2. By manifold reason. a) The natural law is nothing other than the participation of the eternal law in a rational creature. But the eternal law exists, indeed must exist, since without the eternal law there would be neither providence nor governance of the world; and consequently the whole world would perish. Therefore the natural law also exists and must exist in the rational creature. - b) To the whole world the glory of God has been established by the Creator as its end. But each creature must cooperate toward this end, and indeed according to the character of its nature: irrational creatures by following the physical rules imposed upon the world; but rational creatures by freely observing the moral rules wisely imposed by the Creator for the preservation of the moral order and for the good of human society. But these moral rules are the natural law. - c) A third and indeed apodictic argument is drawn from the conscience of every man. For conscience intimately and with undoubted conviction dictates to each one that good is to be done, evil is to be omitted, that certain actions are intrinsically evil, such as to blaspheme, to kill the innocent, etc.; on the contrary, that certain other actions are intrinsically good, as, for example, to honor parents, to worship God, etc. But conscience not only intimately perceives the goodness or malice of these actions, but also persuades itself that these actions are to be done or omitted. Therefore after the transgression of this obligation vivid remorse of conscience arises, while on the contrary after faithful observance of these precepts conscience is tranquil and procures sweet internal peace for man. - The existence of this conscience punishing or rewarding was already acknowledged by the ancient pagans, such as Aeschylus,²² Cicero,²³ Horace,²⁴ Tacitus,²⁵ Juvenal,²⁶ etc. All these things indeed manifestly demonstrate that in the heart of every man there is a law inscribed by the Creator, wholly indelible and independent from all positive statutes. This law is called the natural law. - d) The same is established from the testimony of all peoples. History and ethnography prove that all peoples, even barbarous ones, however much they think differently concerning some moral precepts, nevertheless agree in general moral precepts, for example, that good is to be done, that parents are to be honored, that the divinity is to be worshiped, etc. All peoples also admit that general precepts of this kind do not arise from the decrees of some king or senate or plebiscite, but have been imposed by nature itself or by the divine numen.²⁷

¹⁸ Cf. above n. 100 sqq.

¹⁹ K. v. Savigny, F. Stahl, Puchta, R. v. Jhering, etc.

²⁰ Rom. 2:14-16.

²¹ Encycl. Praestantissimum, June 20, 1888.

²² Agamemnon 179.

²³ De leg. l. 1, c. 14.

²⁴ Ep. 1, 1, 60.

²⁵ Annal. 6, 6.

²⁶ Satyr. 13, 196. Behold the words of this poet:

²⁷ Lactantius (Instit. 6, 8 [Migne, Patr. lat. 6, 660-661]) brings forward the following most beautiful words from Cicero: "There is indeed a true law, right reason, congruent with nature, diffused into all, constant, everlasting; which calls to duty by commanding, deters from fraud by forbidding; which nevertheless neither commands nor forbids the upright in vain, nor moves the wicked by commanding or forbidding. It is not lawful for this law to be abrogated, nor is it permitted that anything be derogated from it, nor can it be wholly abrogated; nor indeed can we be released from this law through the senate or through the people; nor is another expounder or interpreter of it to be sought; nor will there be one law at Rome, another at Athens, one now, another hereafter, but one and everlasting and immutable law will contain all nations and at every time, and there will be one God, as it were the common master and ruler of all, He the inventor, judge, and bearer of this law; and whoever will not obey Him will flee himself, and, having spurned human nature, by this very fact will pay the greatest penalties, even if he should escape the other punishments which are thought such."

153. 3. Subject of the Natural Law is every man of all times and places. Wherefore even children and the insane are subject to the natural law, and consequently they sin materially when they commit acts prohibited by the natural law, for example, by acting immodestly, blaspheming, etc. But although these persons, because of defect of the use of reason, cannot sin formally, nevertheless, since even material sin is something evil and therefore to be avoided, no one can licitly induce them to transgression of the natural law.

154. 4. Object of the Natural Law. As is plain from the things said above in n. 151, the natural law contains all precepts which are deduced from the very nature of man and can be known by the light of reason alone. Therefore the object of this law is the natural moral order necessarily to be observed and naturally known. With St. Thomas a threefold object of the natural law is distinguished:

1. first and most universal principles, which are necessarily known by force of synderesis, namely, good is to be done; evil is to be avoided;²⁸

2. secondary principles, which are immediately deduced from the first principles and are very easily known by every man using reason; to these principles belong all precepts of the Decalogue;²⁹

3. remote conclusions, which are deduced by diligent reasoning from primary and secondary principles, for example, marriage is altogether indissoluble, duel is always illicit, abortion is illicit, etc.

But a punishment vehement and much more savage than those which grave Caeditius or Rhadamanthus devised: to carry night and day one's own witness in the breast.

5. Properties of the Natural Law. The natural law is 1. universal; 2. immutable; 3. it admits neither dispensation properly so called nor epikeia.

1. The natural law is universal, that is, it obliges all men without any exception. Therefore it also obliges infants and the insane, although they cannot transgress it formally, as was already said above.

2. The natural law is immutable, so that nothing may be subtracted from it. For the natural law is founded upon human nature itself and upon the moral order itself, from which nothing essential may be subtracted. Hence it is certain that the natural law cannot be changed from within, for example, it cannot cease, because it has not been given for a time, but in perpetuity; it cannot become unjust, since it commands nothing which is not essentially good, and prohibits nothing which is not essentially evil.

Some authors admit a certain improper change of natural right, namely, a) by way of addition; b) in the conflict of two laws. Nothing prevents certain just statutes of positive law, whether human or divine, from being added to the natural law. And thus positive laws truly are additions to the natural law, which nevertheless remains safe and sound from this.³⁰ But in the conflict of two laws the stronger law is to be observed. Thus, for example, one natural law dictates that a deposit is to be returned; but another natural law, and indeed a stronger one, commands that the neighbor be loved and his grave harm be forestalled. Therefore in the case in which, for example, a furious man should demand his sword deposited with me in order to kill an innocent man, I would have to observe the stronger natural law, namely, of love toward the neighbor, setting aside the lesser law concerning the returning of a deposit. Therefore I would have to retain the deposited sword until the innocent man could save himself.³¹

3. The natural law does not admit dispensation properly so called nor epikeia. Dispensation of law is some change of law from without, namely, made by competent authority; hence to ask whether the natural law is dispensable is the same as to ask whether the natural law is changeable from without. A few ancient authors, such as Occam, Gerson, Peter de Alliaco, etc.,³² thought that God could absolutely dispense in all precepts of the law of nature, indeed abolish the whole natural law, so that even hatred of God would no longer be a sin. This opinion indeed is not only most false, but also today wholly obsolete. But Scotus³³ with many Scotists (others contradicting)³⁴ teaches that God can truly dispense at least in some precepts of the natural law, and notably in the precepts of the second table of the Decalogue, so that, for example, fornication would be licit if God gave a dispensation. Against all these there is established:

²⁸ S. theol. I-II, q. 94, a. 2. Other theologians and authors have placed as the first principle of the natural law: one must live and act according to right reason; or: Love God as the end of all things, and other things on account of God. - The opinion of the Angelic Doctor is much truer, clearer, and more common.

²⁹ The third precept of the Decalogue pertains to the natural law insofar as it commands the external worship of God, but not as to the determination of the day.

³⁰ Blessed Albert the Great neatly says (4, dist. 26, a. 14 ad q. 1): "The law of nature accompanies every law, and therefore this remains in every law."

³¹ S. theol. I-II, q. 94, a. 4-5.

³² Cf. Billuart, De leg. diss. 2, a. 4.

³³ 3, dist. 37. For a refutation of Scotus see Cajetan, Comm. in S. theol. I-II, q. 100, a. 8; but for his defense see Caramuel, Theol. fundam. n. 566 sqq.

³⁴ Cf. Elbel, Theol. mor. Pars 1, Conferentia XVI, n. 444.

155. Thesis: The natural law even from without is immutable and does not admit dispensation properly so called; nevertheless it can happen that, when the matter has been changed, some obligation of the natural law ceases which otherwise would exist.

Thus teach St. Thomas and almost all modern theologians, although sometimes they differ somewhat in mode of speaking. The Angelic Doctor³⁵ says simply and without any limitation: "The precepts of the Decalogue are altogether indispensable." But the precepts of the Decalogue pertain to the natural law, as was said above. - But the reason why the natural law is indispensable proceeds from the fact that it is a participation of the eternal law. For the eternal law is altogether immutable and indispensable, since it is the very reason of divine wisdom. Therefore the same must be said concerning its participation, or concerning the natural law. - Next, the moral natural law is founded upon the very essential condition of human nature. Therefore, since the essential condition of human nature is immutable, the natural law also must remain immutable.

Nevertheless it can happen that, when the matter has been changed, some obligation of the natural law ceases, as is plain from these examples: The natural law prohibits the killing of the innocent, the taking away of another's thing, carnal copulation with an unmarried person, polygamy, etc. But God, who is the supreme and absolute lord of all things and persons, could command that Abraham kill his son Isaac, that the Israelites take the spoils of the Egyptians, that the prophet Hosea have intercourse with a fornicator woman, that polygamy be licit in the Old Testament. For just as God daily sends death to thousands of men, so He could, without injury to natural right, cause the death of Isaac by the aid of Abraham; a fortiori He could distribute the spoils of the Egyptians; likewise He could concede that that woman, until then fornicatory, could be legitimately joined with the prophet Hosea.³⁶ Moreover, concerning this deed of the prophet Hosea there are several other explanations.³⁷ God could also permit polygamy, since it is not against the primary end of marriage.

From what has been said it appears that God never properly dispensed in the natural law, but only improperly, that is, changed the matter of the act. - But if not even God Himself can properly dispense in the natural law, a fortiori no created authority can do this, such as the Church or a civil prince. But if the Church dispenses concerning a ratified marriage or even concerning the consummated marriage of infidels, notwithstanding the indissolubility of marriage introduced from natural right, those dispensations are not dispensations properly so called, but rather improper, and indeed in things which otherwise do not pertain to the primary principles of the natural law and which are founded upon some human fact which lies under the jurisdiction of the Church. Moreover authors, although they admit that the Supreme Pontiff truly can make concessions of this kind, nevertheless by no means agree in the mode of explanation. Some say that God and His vicar, the Supreme Pontiff, can dispense not indeed in the primary and secondary principles of natural right, but in its more remote conclusions. Others explain in this way: The indissolubility of marriage, the obligation of observing a vow made, etc., arises from the free will of the man entering upon a contract of this kind. But God, and by His delegation also the Church, can remit to man an obligation arising from a free promise, just as a master can remit to a servant a contract freely entered upon. After this remission man becomes free, so that, for example, he can enter a new marriage. But whatever may be said of these explanations, no created authority can grant dispensations properly so called in the natural law.

³⁵ S. theol. l. c.

³⁶ Hos. 1:2.

³⁷ Cf. Billuart, De leg. diss. 2, a. 4; St. Bernard, De praecepto et dispensatione c. 3 (Migne, Patr. lat. 182, 864).

156. Even epikeia properly so called cannot be employed in the natural law, because epikeia is a benign interpretation of law according to the mind of the legislator, where the law fails. Therefore where there is no deficient law, there epikeia cannot have place. A created legislator cannot foresee all singular cases and all circumstances, and therefore cannot establish a law which in all occurring cases is just and useful. Therefore in a case in which the law borne by him becomes unjust or harmful, it is licit to employ epikeia, that is, according to the presumed mind of the legislator it is licit to interpret the law or even to omit it. But all these things cannot happen in the natural law, since it is never deficient, but always fitting to human nature. Besides, a case not foreseen by the divine legislator of the natural law cannot occur, since He is omniscient. Below, n. 231, a fuller discussion will return concerning epikeia.

157. 6. Cognition of the Natural Law is had very easily by all, at least as to the primary and secondary principles. Wherefore the Scholastics taught that there exists in man a habit of the first practical principles, or synderesis, by which these principles of natural right are known. But theologians dispute whether and how far invincible ignorance of the natural law is possible, for example, of the malice of pollution, fornication, an officious lie, etc.

That ignorance of some human or positive divine law is possible, all admit, and it is plain of itself. Thus, for example, the divine law itself of receiving the faith can be invincibly unknown by those to whom the faith has never been preached. In this case this negative infidelity would not be a sin, as is also plain from the condemned proposition 68 of Baius: "Purely negative infidelity in those to whom Christ has not been preached is a sin."³⁸ It is not so clear whether someone can invincibly be ignorant of the natural law. Among all there is indeed agreement: a) that the most general precepts of the law of nature cannot be unknown by adults having the use of reason.³⁹ Such precepts are: Good is to be done, evil is to be omitted, and also the precepts of the Decalogue as to substance; b) that remote conclusions deduced from the principles of the natural law can be invincibly unknown, for example, that marriage is indissoluble from natural right. But theologians dispute whether inculpable ignorance of the secondary precepts of the natural law is possible. The truer opinion, more conformable to experience and more common among theologians, is this:

³⁸ Denz. n. 1068.

³⁹ Cf. S. theol. I, q. 79, a. 12, and I-II, q. 94, a. 6.

158. Thesis: The secondary precepts of the law of nature in particular circumstances can inculpably be unknown at least for a time.

This opinion is proved:

1. From St. Augustine,⁴⁰ who, after he had narrated the deed of the Antiochene woman who, with her husband consenting, indeed commanding it, had given the use of her body to another, so that from him she might receive a pound of gold by which she would liberate her husband from captivity and unjust death, does not dare to define that those spouses sinned, and permits each one to judge what he wishes, because those spouses "in no way had judged under those circumstances that that act was adultery." But if no inculpable ignorance of the natural law could be given, it is clear and certain that those spouses sinned gravely. Therefore St. Augustine judged that adultery, which most certainly is prohibited by the natural law, can in some circumstances be thought licit, and consequently that inculpable ignorance of the natural law is possible.⁴¹

2. From reason. Although the natural law is inscribed by the Creator in the hearts of men, nevertheless on account of the clouding of reason (arising both from original sin and not rarely from the morals of some people) it easily happens that in a particular case, especially in a conflict of two laws of natural right, it is morally impossible to know certainly what is to be done. Thus, for example, the natural law commands that the innocent be not condemned. Likewise the natural law commands that a judge sitting in tribunal judge according to the clear and certain testimonies of witnesses. But what must the judge do if from private knowledge he knows certainly that some accused man is innocent, but from the testimonies of several witnesses it is held that the same accused man is guilty?⁴² St. Thomas teaches that in this case the judge is bound to pronounce sentence according to the testimonies of the witnesses; but St. Bonaventure affirms that in this case the judge is bound to absolve the accused from fault. Therefore it is plain that even most holy and most learned men do not agree concerning some precept of the law of nature in certain circumstances. But among the unlearned there will be much easier doubt and inculpable ignorance. This is plain in diverse cases, for example, concerning the liceity of craniotomy, when otherwise the life both of the mother giving birth and of the infant to be born would be in most certain and greatest danger; concerning imperfect marital copula, etc. - From all these things it clearly appears that sometimes the natural law can inculpably be unknown.⁴³

But we have said: at least for a time. For if there is question of sufficiently clear precepts of natural right, that ignorance cannot persist for long without at least some doubt arising. This doubt indeed must be solved by consulting learned men. But if such consultation is neglected, the existing ignorance will no longer be inculpable. A case of this kind can easily occur with regard to the sin of pollution or mollities, which can indeed be unknown by adolescents for a time, but not perpetually. Likewise with regard to the malice of internal acts, namely, of depraved thoughts and desires, especially inefficacious ones.

In the case in which someone from inculpable ignorance transgresses a precept of the natural law, he does not commit formal sin, as is plain from the proposition condemned by Alexander VII on September 7, 1690: "Even if invincible ignorance of natural right is given, in the state of fallen nature this does not excuse the one acting from formal sin."⁴⁴ The contrary was falsely taught by Luther, Calvin, Baius, and the Jansenists.⁴⁵ Nevertheless a transgression of this kind is material sin.

⁴⁰ Lib. 1 de serm. Dom. in monte c. 16 (Migne, Patr. lat. 34, 1254).

⁴¹ In Billuart, De pecc. diss. 5, a. 4.

⁴² Cf. below II, n. 158.

⁴³ Cf. Bouquillon, Theol. mor. fund. n. 78 sq.

⁴⁴ Denz. n. 1292.

⁴⁵ Cf. Billuart, De pecc. diss. 5, a. 4.