Art. 2: THE NATURAL LAW
(_Summa Theologica_, I-II, qq. 93, 94.)
295. Meaning.—The Natural Law is so called for the following reasons: (a) it is received by man, not through special promulgation, but along with his rational nature. Hence, St. Paul says that the Gentiles, who had not received the laws specially promulgated, were a law unto themselves, that is, through their rational nature (Rom., ii. 14); (b) it includes only such precepts as can be known or deduced from the very nature of man, and thus some pagans fulfilled the Law of Moses naturally, i.e., as regards its natural precepts (Rom., ii. 14); (c) it can be known from the natural light of reason without instruction, being a law written on the heart of man (Rom, ii. 15).
The Natural Law is defined theologically as a participation of the Eternal Law in man. Three elements constitute its essence in its integrity: (a) a passive participation of the Eternal Law consisting in man’s nature and faculties with their inclinations to their proper acts and ends. This man shares with all creatures. (b) an active participation in the Eternal Law proper to man. This consists in the activity of man’s intellect through which he shares in God’s providence and government in a special way as one who can rule himself and others. Reason, reflecting upon the natural inclinations and ordering them to their proper acts and ends, formulates (c) a dictate or command of the practical reason. This command constitutes the essence of Natural Law. “Hence the Psalmist after saying (Psalm, IV. 6): _Offer up the sacrifice of justice_, as though some one asked what the works of justice are, adds: _Many say, Who showeth us good things_, in answer to which he says: _The light of thy countenance, O Lord, is signed upon us_. Thus the Psalmist implies that the light of natural reason, whereby we discern what is good and bad, which is the function of the Natural Law, is nothing else than an imprint on us of the divine light. It is therefore evident that the Natural Law is nothing else than the rational creature’s participation in the eternal law” (_Summa Theol_. I-II, q. 91, a.2).
296. Relation of the Natural Law to Other Laws.-(a) The Natural Law is inferior to the Eternal Law; for, while the Eternal Law exists in the mind of God, underived from any other law and is regulative of all created things, the Natural Law exists in the mind of man, as a derivation and image of the Eternal Law and a rule for man’s acts only. (b) It is superior to Positive Law, for all Positive Law is a deduction from or a determination of Natural Law.
297. Division.—Since Natural Law is the reflection of the eternal plan of Divine Wisdom in the reason of man, we cannot distinguish different species of it according to difference of lawgivers or subjects. The objects regulated are, however, different; and hence we may distinguish various precepts of Natural Law.
(a) According to the difference of persons to whom natural duties are owed, there are natural laws concerning God (e.g., that God must be honored), natural laws concerning self (e.g., that one must not commit suicide), and natural laws concerning the neighbor (e.g., that injustice must not be done).
(b) According to the difference of natural inclinations in man, there are, first, natural laws common to him with all beings (e.g., the law of self-preservation, and hence it is a natural duty of man to take sleep, food, drink, remedies, etc., as necessary for life); secondly, natural laws common to him with all sentient beings or animals (e.g., the law of preservation of the species, and hence it is a natural duty of man to rear and provide for his children); thirdly, natural laws proper to man as a rational being (e.g., the laws that he should cultivate his powers of mind and will, and hence it is a natural duty of man to further religion and education, and to organize into societies and to respect the rights of others).
298. According to their necessity for the primary or the secondary end of a natural inclination, the laws of nature are divided into primary and secondary. (a) The primary end of a natural inclination is the conservation of a natural good; and so it is a primary law of nature that man should take the food, drink, sleep and exercise necessary for life, and that he should avoid poison or other things that cause death. (b) The secondary end of a natural inclination is the betterment of a natural good, or its easier conservation; thus, it is a secondary law of nature that man should use those kinds of food or drink that promote his health, that he should be careful about his diet, practise moderation, etc.
299. Primary and secondary laws of nature are also explained as follows: (a) a primary law is one that expresses the principal purpose of a natural inclination (e.g., social good, that is, the begetting and rearing of children, is the primary law of the married state); (b) the secondary law is one that expresses a less important purpose of a natural inclination. For example, individual good (i.e., companionship, mutual assistance, the practice of virtue and freedom from temptation) is the secondary purpose to be promoted in the married state.
300. Precepts of the Natural Law may be divided also on account of the different relations they have to one another or to our knowledge.
(a) According to the priority they have among themselves, the laws of nature are divided into the first principle and the secondary principles. The first principle, which is general, which depends on no other, and which is the root of all the others, is: “Good must be done, evil omitted.” The secondary principles are particular, and they apply this general principle to the natural inclinations of man mentioned above, which reason indicates as ends of action—i.e., as goods to be sought.
(b) According to the priority they have with respect to our knowledge of them, the laws of nature are divided, first, into axiomatic precepts, which are evident and are granted by all (e.g., that good is to be done, that one should follow reason, that one should not do to others what one does not wish done to oneself etc.), and, secondly, into inferred precepts (e.g., that one should not steal from others, as one does not wish others to steal from oneself).
301. The inferred precepts are also of two kinds, namely, general and particular. (a) The general precepts are those that are deduced immediately from the axioms as universal conclusions (e.g., the commandments of the Decalogue, the principle that one should return what one borrowed). (b) The particular precepts are those that are deduced only remotely from the axioms as conclusions about cases in which many particular conditions and circumstances are involved (e.g., many conclusions about contracts, the conclusion that a loan is to be paid in some particular way, at this particular time, etc.).
302. According to the invariability or permanence of their subject-matter, the laws of nature are of two kinds, namely, necessary and contingent. (a) The necessary laws are those whose matter always bears the same relation of essential conformity to or difformity from reason. For example, the command, “Thou shalt not take the name of the Lord in vain,” is necessary, because God remains always worthy of honor, and there is no conceivable or possible case in which it could become useful to speak of Him with dishonor. (b) The contingent laws of nature are those whose matter generally, but not always, bears the same essential relation to right reason. For example, the command, “Thou shalt not kill,” is contingent, because, though man generally remains worthy of having his life respected by others, there are cases when it might be injurious to the common welfare, and hence to natural law, that an individual be permitted to live, as when he has committed and been convicted of a capital crime.
303. According to the manner in which they oblige, the laws of nature are twofold, namely, absolute and relative. (a) Absolute laws are those that oblige for every case and condition, because the matter with which they are concerned is intrinsically good or bad in every instance (e.g., the laws forbidding marriage between parent and child, the law against polyandry). (b) Relative laws of nature are those that oblige except in case of a most grave public necessity, because the matter with which they are concerned is generally and of its very nature becoming or unbecoming (e.g., the laws forbidding marriage between brother and sister, the law forbidding polygamy).
304. According to the manner in which the obligation is contracted, laws of nature are of two kinds, viz., those whose obligatory force depends entirely on the nature of things (e.g., the law that God must be honored), and those whose obligatory force depends upon, an act of the will of man freely undertaking an obligation, which the nature of things then demands that he fulfill (e.g., the laws that those who have made vows, oaths, contracts, etc., should live up to that which they have freely promised).
305. Properties.—Since the Natural Law is the reflection of God’s Eternal Law impressed on the rational nature of man, it has the following properties: (a) it is both declarative and imperative; being immanent in man, it declares to him his duty; being transcendent in its origin, it speaks with the voice of authority; (b) it is universal, or for all, for it declares the necessities of nature, which are the same in all men; (c) it is unchangeable, that is, it admits of neither abrogation, nor dispensation, nor emendatory interpretation, for the essences of things, on which it is based, do not change; (d) it is recognizable and indelible, that is, it cannot fail to be known and cannot be forgotten by mankind, for it is promulgated through the light of reason given to man.
306. The Natural Law is of universal obligation. It is in force in all places, at all times, and for all persons. (a) Thus, those who have not the use of reason, such as infants and the insane, are subject to the Natural Law on account of their human nature which is injured by any transgression of its inclinations. Their ignorance, of course, excuses them from formal sin (see 24 sqq., 97 sqq.). Example: It is sinful to induce or permit children to blaspheme or become intoxicated, not only because of scandal or of harm done to them, but also because such things are necessarily repugnant to their dignity as human beings. (b) those who have the use of reason are subject to the Natural Law, and their transgressions are imputable as formal sins and incur the debt of punishment.
307. The Natural Law is unchangeable, not as regards additions, but as regards subtractions. (a) Additions may be made to the Natural Law, for, in many points not determined by it, it is well that supplementary regulations be made to provide for particular situations. These additions, made by Positive Law, divine and human, are amplifications rather than changes, for they must not be out of harmony with Natural Law. (b) Subtractions may not be made from the Natural Law—that is, there can be no exception when it declares that a certain thing must always be observed, and there can be no abrogation when it declares that a certain thing must be observed usually.
308. From the foregoing it follows that no precept of the Natural Law can be abrogated—that is, repealed and deprived of all force, so that what was today a precept of nature should no longer be such tomorrow; for the necessities of nature on which the Natural Law is based do not change.
309. As to the question whether any precepts of the Natural Law may be dispensed or not, distinction must be made between two kinds of dispensation.
(a) A dispensation in the strict sense is granted when a legislator relaxes for a particular case the obligation of a law, although the subject-matter of the law still remains. Example: Titus is in the class of those who are bound by the law of fast, but he is exempted by competent authority from the obligation of the law.
(b) A dispensation in the wide sense is granted when the subject-matter of the law is taken away by the legislator himself or by another, so that it ceases to be comprehended under the law, although the obligation of the law still remains. Example: Balbus owed money to Caius, but, as Caius forgave him the debt, he is no longer in the class of those who are bound by law as debtors to Caius; he is not exempted, however, from the obligation of the general law that one must pay one’s debts.
310. There are various opinions as to the possibility of a dispensation from the Natural Law granted by God, but the following doctrine seems the most probable.
(a) God Himself cannot dispense in any way from those precepts whose matter is necessary (see 302), such as axiomatic precepts (viz., those that prohibit malice and those that command duties to be fulfilled at a proper time and place). For all the subject-matter of these precepts is intrinsically either consonant with or dissonant from right reason. Example: God could not by decree abolish the Ten Commandments, for, as long as God is God, He must remain worthy of worship, praise and love; and, as long as man is man, it must be against his rational nature to murder, steal, lie. etc.
(b) God cannot grant a dispensation in the strict sense from those precepts of the Natural Law whose matter is contingent, such as the precepts against the taking of human life, against taking possessions from others against their will, etc. For, as long as the subject-matter of these precepts remains what it is supposed to be by the law, transgression of them is necessarily opposed to reason. Example: God cannot command the killing of a person who has the right to life, nor the taking of property that rightly belongs to another.
(c) God can grant a dispensation in the wide sense from contingent precepts of the Natural Law—that is, He can make a change as regards the subject-matter, so that it no longer falls under the law. Thus, since God is the supreme Lord of life and property, He can without injury to human rights command that a person be put to death or deprived of his property by another. These acts would not constitute murder (i.e., unjust homicide) or stealing (i.e., unlawful taking); for God has a higher claim on life and possessions than the immediate owners have. Examples: The command to Abraham to kill his son was not a dispensation from the law against murder any more than the sending of death to the first-born of Egypt was the commission of murder by God. The command given the Israelites to carry away with them the goods of the Egyptians was not a dispensation from the law against theft, any more than the destruction of the fruits of the Egyptians by plagues was the commission of theft by God.
311. Is God able to make a decree which sets up a most grave public necessity opposed to the observance of a law of nature?
(a) If there is question of absolute laws (see 303), this cannot be done, for God cannot deny Himself by making a disposition contrary to His Eternal Law. Example: We do not read that God ever sanctioned polyandry or marriage between parent and child, and it seems that He could never permit such things as lawful.
(b) If there is question of relative laws (see 303), the decree in question can be made by God; for the unbecomingness of that which is forbidden by a relative law passes away in the face of a great need. Example: Since God desired the propagation of the human race from one man and one woman, marriage between brothers and sisters was not against the Natural Law at the beginning. Since God desired the speedy multiplication of the chosen people after the patriarchal era, polygamy was not repugnant to nature among the Jews of that period.
312. Is God able to remove a natural obligation in a case of private necessity, that is, when the fulfillment would be harmful to an individual?
(a) Natural obligations that do not depend upon any free consent of the will given to them (see 304) cannot be removed except by a dispensation widely so-called and when their matter is contingent (as explained in 309-310). Examples: God could not dispense an individual from the duty of confessing Him in order to escape death, for the subject-matter of the law here is necessary. God, could dispense an individual from the obligation of not taking the property of another, for God is the principal owner of all things, including those possessed by others.
(b) Natural obligations that depend upon the act or deed of human beings consenting to obligation (see 304) can be removed. For since human beings cannot know all the circumstances existent, or all the conditions that will arise, it can happen that a thing agreed to or promised is only seemingly good, or will change from good to bad, so that while the promise or agreement made is in itself good and naturally obligatory, its fulfillment would work harm and evil, or be useless, or would prevent the accomplishment of a greater good. It is reasonable, therefore, that God should release from obligation here, thus changing the subject-matter of the law, so that it is no longer comprehended under the law (see 309-310). Example: Titus vows or swears that he will give a certain alms or make a certain pilgrimage; but, when the time for fulfillment arrives, his circumstances have so changed that it would not be advisable for him to keep the promise made. The Church, acting in the name of God, can declare that the subject-matter of this promise has become harmful and is not longer suitable, and hence that the obligation has ceased.
313. Human Authority and Modification of the Natural Law.
(a) Additions to the Natural Law may be made, not only by positive laws of God, but also by human laws of Church or State, through the introduction of that which Natural Law permits, or the determination or confirmation of that which Natural Law contains implicitly or explicitly. Examples: Division of property rights introduced by the law of nations; conditions for valid contracts determined by particular codes; the laws against theft and murder confirmed by definite penalties prescribed for those crimes.
(b) Subtractions from Natural Law cannot be made by any human authority, for God has not delegated His power of dispensing which He has as supreme owner of all things. Examples: No human authority could authorize a father to sacrifice his innocent son, nor permit a servant to carry away the effects that belong to his employer.
314. Apparent Cases of Dispensation from Natural Law made by Human Authority. (a) The Church frees from the obligation of vows, contracts and promissory oaths, from impediments to marriage, from espousals, etc. In so doing, however, she does not dispense from the Natural Law that vows, contracts, etc., should be fulfilled, but only declares in the name of God that the subject-matter of an obligation contracted by act of man’s will has become unsuitable for vow, contract, etc., and hence is no longer comprehended under the law.
(b) Societies or private individuals can free from the obligation of paying or returning to them what they have a right to, as when a creditor forgives a debt, or an owner permits a thief to keep what he stole. In so doing, however, they do not dispense from the law of nature that one should pay one’s debts and not keep ill-gotten goods; they only change the quality of the things in question so that they cease to be due another or ill-gotten, and hence no longer fall under the law. This differs, too, from the dispensation that God can grant; for He can transfer rights without the consent of the immediate owner (see 310).
315. Interpretation—that is, explanation of the law which indicates whether or not it obliges in a particular case—may be applied to the Natural Law as follows:
(a) Interpretation which explains the intention the lawgiver had in making the law and the sense he gave to the words of the law (verbal interpretation), may be made when either a law itself is not entirely clear, or some person is not clever enough to see its meaning. Example: The commandment, “Thou shalt not kill,” needs to be interpreted, for it does not forbid every kind of killing.
(b) Interpretation which explains the intention a lawgiver would have had, had he foreseen a particular case in which his law would be harmful, and which therefore sets the will of the lawgiver against the words of the law (emendatory interpretation, _epieikeia_), may not be applied to the Natural Law; for God, unlike human legislators, foresees things not only in general, but also in particular, and hence there is no room for correction or benign interpretation of natural laws. Example: Titus, who was a chronic invalid, committed suicide in order that his family might be freed from distress. He argued that the Fifth Commandment did not foresee the difficulties of earning a living under modern conditions, and that his sacrifice would be pleasing to God. Titus did not reason well, for suicide is forbidden for motives that apply universally (e.g., that society, and especially one’s family, are injured by the act of suicide).
316. Verbal interpretation of the Natural Law is made as follows: (a) by private authority—that is, by those who are competent, on account of learning and prudence, to understand the meaning of the law, such as moral theologians; (b) by public authority—that is, by those who are appointed to rule, with the prerogative of declaring the meaning of the Natural Law. The Pope, since he must feed the flock of Christ, is divinely constituted to interpret Natural Law, and does so authentically and infallibly. Thus, the Church declares that certain matrimonial impediments are natural, and therefore incapable of being dispensed.
On the competence of the Church to give authoritative interpretations of the natural law in the field of morals, Pius XII has spoken clearly and forcefully: “... it must openly and firmly be held that the power of the Church has never been limited to the boundaries of strictly religious matters’ as they are called; but the whole content of the natural law, its institution, interpretation and application are within its power insofar as its moral element is concerned. For the observation of the natural law, by the ordination of God, is the way by which man must strive to attain his supernatural end. On the road to this supernatural end. it is the Church that is his leader and guide. This is the way the Apostles acted, and from the earliest times the Church held to this way of acting as it does today—and not in the manner of a private leader and counselor, but from the command and authority of God” (AAS 46 [1954] 671-672).
317. From the foregoing it follows that the Natural Law is so unchangeable that it cannot be abrogated or properly dispensed, or given an emendatory interpretation. But, though the law itself remains, there are cases in which non-observance of it is excused from guilt. These cases can be reduced to physical and moral impossibility.
(a) In cases of physical impossibility (i.e., when the powers requisite for observance are wanting), one is manifestly excused; for law is reasonable, and it is not reasonable to require impossibilities. Examples: Infants are not guilty of sin against the Natural Law, when they do not pray; for they lack the use of reason, which is presupposed by the notion of prayer. He who is unable to work is not obliged to earn support for relatives.
(b) In cases of moral impossibility (i.e., when a law cannot be kept without the infringement of a higher law or the loss of a higher good), one is also excused; for it is unreasonable to prefer the less to the more important. Example: Titus lends a revolver to Balbus. Later he asks that it be returned to him, as he wishes to kill himself. Now, property is less valuable than life, and hence Balbus is unable in this case to observe the law which requires that things borrowed must be returned.
318. Moral impossibility is also defined as the inability to observe the law without serious injury or loss to oneself or a third party. Serious injuries are such as deprive some one of great goods, such as the use of reason, life, knowledge, friendship, health, reputation, property. Serious losses are such as prevent one from obtaining notable goods, The following rules indicate when grave inconvenience excuses, and when it does not excuse, from the guilt arising from the non-observance of Natural Law:
(a) when the law is negative (i.e., prohibitory), no inconvenience excuses from sin; for that which is forbidden by the Natural Law is always morally evil, and hence more to be shunned than even the greatest physical evil, or death. Example: One is obliged, under grave or light sin, as the case may be, to forfeit all temporal goods rather than blaspheme, murder, lie, etc.;
(b) when the law is affirmative (or mandatory), an inconvenience which, all things considered, is really and relatively grave, excuses from sin; for that which is commanded by the Natural Law is not always morally obligatory, but only at the right time and in the right circumstances (see 371), and hence its omission is not always morally evil. Examples: Sempronius vowed that he would go on foot to a place of pilgrimage, but when the day came he had a sprained ankle that would be badly injured if he walked. Caius received a jewel stolen from Balbus and promised that he would return it at once to the owner, but he finds that he cannot do so now without danger, either of the arrest of himself or of the one who took the jewel. Titus sees a person who has been seriously injured lying by the roadside, but he is tired, and neither gives help himself nor summons aid. In the first two cases the inconvenience is grave, and hence Sempronius may ride to the place of pilgrimage, and Caius may return the jewel to Balbus later; but the inconvenience of Titus is slight, and does not excuse him from sin.
319. Just as the Natural Law is unchangeable, because based on the unchangeable Eternal Law instituting the nature of man, so is it easily knowable, because it is promulgated by the light of reason. Hence: (a) invincible ignorance of the entire Natural Law is impossible in any person who has the use of reason; (b) complete forgetfulness of the Natural Law by mankind is impossible.
320. Those who have not the use of reason, either habitually (as children and the insane) or actually (as the intoxicated), may be invincibly ignorant of the Natural Law—for example, they may be unable to perceive even the difference between right and wrong. As to those who have the use of reason, they can be ignorant of the Natural Law only as follows:
(a) they cannot ever be invincibly ignorant of the most general precepts (such as “good is to be done,” “evil is to be avoided”), for since they know the difference between right and wrong, they must also perceive that which is contained in the concepts of right and wrong, viz., that the former is something desirable and which ought to be done, the latter something undesirable which must not be done;
(b) one cannot, as a rule, be invincibly ignorant of those precepts that are immediately inferred as necessary conclusions from the most general precepts (such as “that which was borrowed must be returned”), for the conclusion follows so easily from the manifest principle that only in exceptional cases could one be excused for not knowing its truth;
(c) one can, even as a rule, be ignorant of precepts that are inferred as necessary but very remote conclusions from the most general precepts, (such as “that which was borrowed must be returned at such a time or place, or in such a manner or condition”), for this conclusion is so far removed from its premise, and there are so many factors to be considered, that considerable knowledge and skill in reasoning are required for a correct judgment—things in which many people are lacking.
321. The Commandments of the Decalogue follow directly from the most general precepts of the Natural Law, and so to them may be applied what was said in the previous paragraph. Hence: (a) generally speaking, no person who has the use of reason can be invincibly ignorant of the Commandments. St. Paul blames the pagans as inexcusable in various sins committed against the Decalogue; (b) in special cases, a person who has the use of reason can be invincibly ignorant of one or more Commandments; for while the Commandments may be easily inferred by most persons from the common principles of right and wrong, there are sometimes involuntary impediments that hinder the right employment of reason. Thus, children and older persons whose mentality is undeveloped, although they know the difference between right and wrong, are frequently unable to draw the conclusion that follows from it (e.g., that one should not tell lies).
322. The Commandments regarding which invincible ignorance may most easily exist are: (a) those that deal with merely internal acts, for the malice of violating them is less apparent. Hence, many theologians admit that even among Christians the wickedness of sinful thoughts and desires may be inculpably unknown, at least when the wickedness of the corresponding external acts is also not known; (b) those that deal with the control of sensuality, for the impulse to inordinate acts is at times most vehement. Unde theologi sunt qui affirmant malitiam peccatorum externorum contra sextum invincibiliter ignorari posse, non solum apud infideles, sed etiam apud Christianos, ita quod ab adolescentibus facile ad tempus ignorari possit malitia mollitiei.
323. If a Commandment be applied to some particular case in which there are many circumstances to be considered, or some reason that appears to change the subject-matter of the law, even adults who have the perfect use of reason may be invincibly ignorant; for in such instances we are considering, not an immediate, but a remote conclusion from the general principles of Natural Law.
(a) If the case is difficult relatively (i.e., in view of the training or lack of education of the person studying it), there can be invincible ignorance, at least for a time. Examples: Jepthe, according to St. Jerome, appears to have been invincibly ignorant that it was not lawful for him to slay his daughter. Being a soldier and living in a rude age, he perhaps did not appreciate the sacredness of human life. Unlettered persons might conceivably think in good faith that it is not wrong to commit perjury in order to help one in danger, to steal in order to pay debts, to think evil if there is no intention to fulfill it, to do what the majority do or what is tolerated, etc.
(b) If the case is difficult absolutely (i.e., in view of the matter itself, which is complicated and obscure), there can be invincible ignorance, even for a long time. Thus, it is so difficult to settle many problems pertaining to justice (i.e., to the application of the Seventh Commandment) that we find professional theologians who take opposite sides, or admit that, speculatively speaking, they do not know where the truth lies.
324. The Natural Law can never be erased from the hearts of men. (a) In abnormal circumstances only, as when the general power of reasoning has been weakened or lost, can the Natural Law be forgotten. Thus, to a degenerate who becomes violently insane murder and other crimes may appear as good acts. But no community could govern itself by the standards of madmen and long survive. (b) In normal circumstances (i.e., as long as the general power of reasoning remains unimpaired), the Natural Law cannot be forgotten, as far as its general principles or immediate conclusions are concerned, although it may be overlooked or lost sight of when it is applied to particular cases, or when remote conclusions are deduced from it.
325. As long, therefore, as a body of men remain sane, even though they be uncivilized or addicted to crime, they cannot become oblivious of the Natural Law. (a) The general principles (“good is to be done,” “evil is to be avoided”) cannot vanish from the mind, although, in particular affairs, anger, pleasure, or some other passion may prevent men from thinking about them. Thus, when the mob spirit takes hold of a crowd, it becomes intent only on violence or revenge, and gives no thought to conscience. (b) The secondary precepts, such as those contained in the Decalogue, cannot be obliterated from the mind, although in applying them to concrete situations a people may go astray.
There are many examples of laws, both ancient and modern, which permitted or commanded, for particular cases, things contrary to the current application of natural precepts. Thus, the Spartans and the Romans ordered the murder of infants who were weakly and of slaves whose master had been killed. Some ancient races encouraged robberies committed beyond the boundaries of the states, and savage tribes have been found who had the practice of putting to death parents who were aged or infirm.
326. The causes of wrong applications of the Natural Law are the following:
(a) Some causes are involuntary. Thus, the correct application may be difficult, as when more than one moral principle has to be considered and applied; or, if the case is not difficult, the person who makes the application may be mentally undeveloped, or his mind may be blinded on account of his bad education or environment. Examples: The races who saw no infamy in robbery committed against their neighbors, lived in a wild age when such acts of violence seemed necessary as measures of self-protection. The savage killed his aged parents, because to his untutored mind this seemed an act of mercy.
(b) Some causes are voluntary, such as neglect of the truth, vicious habits, etc. Examples: St. Paul blames the pagans for their idolatry, because they had darkened their own minds about God. Pirates and bandits who came to regard violence as necessary for their own defense were responsible for their state of mind, inasmuch as they had chosen a life of crime.
327. Transgression of Natural Law, therefore, is not imputable as formal sin if it is not voluntary. Hence: (a) lack of knowledge excuses, when ignorance is involuntary (e.g., those who have not the use of reason, as infants and the unconscious; children and others mentally undeveloped who cannot grasp the meaning of some precept; educated persons who are unable to get a right solution of some knotty problem of morals, etc.); (b) lack of consent excuses in whole or in part (as when one acts through fear).