Question 94. The natural law What is the natural law? What are the precepts of the natural law? Are all acts of virtue prescribed by the natural law? Is the natural law the same in all? Is it changeable? Can it be abolished from the heart of man?

t de lege naturali. Et circa hoc quaeruntur sex. Primo, quid sit lex naturalis. Secundo, quae sint praecepta legis naturalis. Tertio, utrum omnes actus virtutum sint de lege naturali. Quarto, utrum lex naturalis sit una apud omnes. Quinto, utrum sit mutabilis. Sexto, utrum possit a mente hominis deleri.

Objection 1. It would seem that the natural law is a habit. Because, as the Philosopher says (Ethic. ii, 5), “there are three things in the soul: power, habit, and passion.” But the natural law is not one of the soul’s powers: nor is it one of the passions; as we may see by going through them one by one. Therefore the natural law is a habit.

q. 94 a. 1 arg. 1 Ad primum sic proceditur. Videtur quod lex naturalis sit habitus. Quia ut philosophus dicit, in II Ethic., tria sunt in anima, potentia, habitus et passio. Sed naturalis lex non est aliqua potentiarum animae, nec aliqua passionum, ut patet enumerando per singula. Ergo lex naturalis est habitus.

Objection 2. Further, Basil [Damascene, De Fide Orth. iv, 22 says that the conscience or “synderesis” is the “law of our mind”; which can only apply to the natural law. But the “synderesis” is a habit, as was shown in the I, 79, 12. Therefore the natural law is a habit.

q. 94 a. 1 arg. 2 Praeterea, Basilius dicit quod conscientia, sive synderesis, est lex intellectus nostri, quod non potest intelligi nisi de lege naturali. Sed synderesis est habitus quidam, ut in primo habitum est. Ergo lex naturalis est habitus.

Objection 3. Further, the natural law abides in man always, as will be shown further on (6). But man’s reason, which the law regards, does not always think about the natural law. Therefore the natural law is not an act, but a habit.

q. 94 a. 1 arg. 3 Praeterea, lex naturalis semper in homine manet, ut infra patebit. Sed non semper ratio hominis, ad quam lex pertinet, cogitat de lege naturali. Ergo lex naturalis non est actus, sed habitus.

On the contrary, Augustine says (De Bono Conjug. xxi) that “a habit is that whereby something is done when necessary.” But such is not the natural law: since it is in infants and in the damned who cannot act by it. Therefore the natural law is not a habit.

q. 94 a. 1 s. c. Sed contra est quod Augustinus dicit, in libro de bono coniugali, quod habitus est quo aliquid agitur cum opus est. Sed naturalis lex non est huiusmodi, est enim in parvulis et damnatis, qui per eam agere non possunt. Ergo lex naturalis non est habitus.

I answer that, A thing may be called a habit in two ways. First, properly and essentially: and thus the natural law is not a habit. For it has been stated above (90, 1, ad 2) that the natural law is something appointed by reason, just as a proposition is a work of reason. Now that which a man does is not the same as that whereby he does it: for he makes a becoming speech by the habit of grammar. Since then a habit is that by which we act, a law cannot be a habit properly and essentially. Secondly, the term habit may be applied to that which we hold by a habit: thus faith may mean that which we hold by faith. And accordingly, since the precepts of the natural law are sometimes considered by reason actually, while sometimes they are in the reason only habitually, in this way the natural law may be called a habit. Thus, in speculative matters, the indemonstrable principles are not the habit itself whereby we hold those principles, but are the principles the habit of which we possess.

q. 94 a. 1 co. Respondeo dicendum quod aliquid potest dici esse habitus dupliciter. Uno modo, proprie et essentialiter, et sic lex naturalis non est habitus. Dictum est enim supra quod lex naturalis est aliquid per rationem constitutum, sicut etiam propositio est quoddam opus rationis. Non est autem idem quod quis agit, et quo quis agit, aliquis enim per habitum grammaticae agit orationem congruam. Cum igitur habitus sit quo quis agit, non potest esse quod lex aliqua sit habitus proprie et essentialiter. Alio modo potest dici habitus id quod habitu tenetur, sicut dicitur fides id quod fide tenetur. Et hoc modo, quia praecepta legis naturalis quandoque considerantur in actu a ratione, quandoque autem sunt in ea habitualiter tantum, secundum hunc modum potest dici quod lex naturalis sit habitus. Sicut etiam principia indemonstrabilia in speculativis non sunt ipse habitus principiorum, sed sunt principia quorum est habitus.

Reply to Objection 1. The Philosopher proposes there to discover the genus of virtue; and since it is evident that virtue is a principle of action, he mentions only those things which are principles of human acts, viz. powers, habits and passions. But there are other things in the soul besides these three: there are acts; thus “to will” is in the one that wills; again, things known are in the knower; moreover its own natural properties are in the soul, such as immortality and the like.

q. 94 a. 1 ad 1 Ad primum ergo dicendum quod philosophus intendit ibi investigare genus virtutis, et cum manifestum sit quod virtus sit quoddam principium actus, illa tantum ponit quae sunt principia humanorum actuum, scilicet potentias, habitus et passiones. Praeter haec autem tria sunt quaedam alia in anima, sicut quidam actus, ut velle est in volente; et etiam cognita sunt in cognoscente; et proprietates naturales animae insunt ei, ut immortalitas et alia huiusmodi.

Reply to Objection 2. “Synderesis” is said to be the law of our mind, because it is a habit containing the precepts of the natural law, which are the first principles of human actions.

q. 94 a. 1 ad 2 Ad secundum dicendum quod synderesis dicitur lex intellectus nostri, inquantum est habitus continens praecepta legis naturalis, quae sunt prima principia operum humanorum.

Reply to Objection 3. This argument proves that the natural law is held habitually; and this is granted.

q. 94 a. 1 ad 3 Ad tertium dicendum quod ratio illa concludit quod lex naturalis habitualiter tenetur. Et hoc concedimus.

To the argument advanced in the contrary sense we reply that sometimes a man is unable to make use of that which is in him habitually, on account of some impediment: thus, on account of sleep, a man is unable to use the habit of science. In like manner, through the deficiency of his age, a child cannot use the habit of understanding of principles, or the natural law, which is in him habitually.

q. 94 a. 1 ad 4 Ad id vero quod in contrarium obiicitur, dicendum quod eo quod habitualiter inest, quandoque aliquis uti non potest propter aliquod impedimentum, sicut homo non potest uti habitu scientiae propter somnum. Et similiter puer non potest uti habitu intellectus principiorum, vel etiam lege naturali, quae ei habitualiter inest, propter defectum aetatis.

Objection 1. It would seem that the natural law contains, not several precepts, but one only. For law is a kind of precept, as stated above (Question 92, Article 2). If therefore there were many precepts of the natural law, it would follow that there are also many natural laws.

q. 94 a. 2 arg. 1 Ad secundum sic proceditur. Videtur quod lex naturalis non contineat plura praecepta, sed unum tantum. Lex enim continetur in genere praecepti, ut supra habitum est. Si igitur essent multa praecepta legis naturalis, sequeretur quod etiam essent multae leges naturales.

Objection 2. Further, the natural law is consequent to human nature. But human nature, as a whole, is one; though, as to its parts, it is manifold. Therefore, either there is but one precept of the law of nature, on account of the unity of nature as a whole; or there are many, by reason of the number of parts of human nature. The result would be that even things relating to the inclination of the concupiscible faculty belong to the natural law.

q. 94 a. 2 arg. 2 Praeterea, lex naturalis consequitur hominis naturam. Sed humana natura est una secundum totum, licet sit multiplex secundum partes. Aut ergo est unum praeceptum tantum legis naturae, propter unitatem totius, aut sunt multa, secundum multitudinem partium humanae naturae. Et sic oportebit quod etiam ea quae sunt de inclinatione concupiscibilis, pertineant ad legem naturalem.

Objection 3. Further, law is something pertaining to reason, as stated above (Question 90, Article 1). Now reason is but one in man. Therefore there is only one precept of the natural law.

q. 94 a. 2 arg. 3 Praeterea, lex est aliquid ad rationem pertinens, ut supra dictum est. Sed ratio in homine est una tantum. Ergo solum unum praeceptum est legis naturalis.

On the contrary, The precepts of the natural law in man stand in relation to practical matters, as the first principles to matters of demonstration. But there are several first indemonstrable principles. Therefore there are also several precepts of the natural law.

q. 94 a. 2 s. c. Sed contra est quia sic se habent praecepta legis naturalis in homine quantum ad operabilia, sicut se habent prima principia in demonstrativis. Sed prima principia indemonstrabilia sunt plura. Ergo etiam praecepta legis naturae sunt plura.

I answer that, As stated above (Question 91, Article 3), the precepts of the natural law are to the practical reason, what the first principles of demonstrations are to the speculative reason; because both are self-evident principles. Now a thing is said to be self-evident in two ways: first, in itself; secondly, in relation to us. Any proposition is said to be self-evident in itself, if its predicate is contained in the notion of the subject: although, to one who knows not the definition of the subject, it happens that such a proposition is not self-evident. For instance, this proposition, “Man is a rational being,” is, in its very nature, self-evident, since who says “man,” says “a rational being”: and yet to one who knows not what a man is, this proposition is not self-evident. Hence it is that, as Boethius says (De Hebdom.), certain axioms or propositions are universally self-evident to all; and such are those propositions whose terms are known to all, as, “Every whole is greater than its part,” and, “Things equal to one and the same are equal to one another.” But some propositions are self-evident only to the wise, who understand the meaning of the terms of such propositions: thus to one who understands that an angel is not a body, it is self-evident that an angel is not circumscriptively in a place: but this is not evident to the unlearned, for they cannot grasp it. Now a certain order is to be found in those things that are apprehended universally. For that which, before aught else, falls under apprehension, is “being,” the notion of which is included in all things whatsoever a man apprehends. Wherefore the first indemonstrable principle is that “the same thing cannot be affirmed and denied at the same time,” which is based on the notion of “being” and “not-being”: and on this principle all others are based, as is stated in Metaph. iv, text. 9. Now as “being” is the first thing that falls under the apprehension simply, so “good” is the first thing that falls under the apprehension of the practical reason, which is directed to action: since every agent acts for an end under the aspect of good. Consequently the first principle of practical reason is one founded on the notion of good, viz. that “good is that which all things seek after.” Hence this is the first precept of law, that “good is to be done and pursued, and evil is to be avoided.” All other precepts of the natural law are based upon this: so that whatever the practical reason naturally apprehends as man’s good (or evil) belongs to the precepts of the natural law as something to be done or avoided. Since, however, good has the nature of an end, and evil, the nature of a contrary, hence it is that all those things to which man has a natural inclination, are naturally apprehended by reason as being good, and consequently as objects of pursuit, and their contraries as evil, and objects of avoidance. Wherefore according to the order of natural inclinations, is the order of the precepts of the natural law. Because in man there is first of all an inclination to good in accordance with the nature which he has in common with all substances: inasmuch as every substance seeks the preservation of its own being, according to its nature: and by reason of this inclination, whatever is a means of preserving human life, and of warding off its obstacles, belongs to the natural law. Secondly, there is in man an inclination to things that pertain to him more specially, according to that nature which he has in common with other animals: and in virtue of this inclination, those things are said to belong to the natural law, “which nature has taught to all animals” [Pandect. Just. I, tit. i], such as sexual intercourse, education of offspring and so forth. Thirdly, there is in man an inclination to good, according to the nature of his reason, which nature is proper to him: thus man has a natural inclination to know the truth about God, and to live in society: and in this respect, whatever pertains to this inclination belongs to the natural law; for instance, to shun ignorance, to avoid offending those among whom one has to live, and other such things regarding the above inclination.

q. 94 a. 2 co. Respondeo dicendum quod, sicut supra dictum est, praecepta legis naturae hoc modo se habent ad rationem practicam, sicut principia prima demonstrationum se habent ad rationem speculativam, utraque enim sunt quaedam principia per se nota. Dicitur autem aliquid per se notum dupliciter, uno modo, secundum se; alio modo, quoad nos. Secundum se quidem quaelibet propositio dicitur per se nota, cuius praedicatum est de ratione subiecti, contingit tamen quod ignoranti definitionem subiecti, talis propositio non erit per se nota. Sicut ista propositio, homo est rationale, est per se nota secundum sui naturam, quia qui dicit hominem, dicit rationale, et tamen ignoranti quid sit homo, haec propositio non est per se nota. Et inde est quod, sicut dicit Boetius, in libro de Hebdomad., quaedam sunt dignitates vel propositiones per se notae communiter omnibus, et huiusmodi sunt illae propositiones quarum termini sunt omnibus noti, ut, omne totum est maius sua parte, et, quae uni et eidem sunt aequalia, sibi invicem sunt aequalia. Quaedam vero propositiones sunt per se notae solis sapientibus, qui terminos propositionum intelligunt quid significent, sicut intelligenti quod Angelus non est corpus, per se notum est quod non est circumscriptive in loco, quod non est manifestum rudibus, qui hoc non capiunt. In his autem quae in apprehensione omnium cadunt, quidam ordo invenitur. Nam illud quod primo cadit in apprehensione, est ens, cuius intellectus includitur in omnibus quaecumque quis apprehendit. Et ideo primum principium indemonstrabile est quod non est simul affirmare et negare, quod fundatur supra rationem entis et non entis, et super hoc principio omnia alia fundantur, ut dicitur in IV Metaphys. Sicut autem ens est primum quod cadit in apprehensione simpliciter, ita bonum est primum quod cadit in apprehensione practicae rationis, quae ordinatur ad opus, omne enim agens agit propter finem, qui habet rationem boni. Et ideo primum principium in ratione practica est quod fundatur supra rationem boni, quae est, bonum est quod omnia appetunt. Hoc est ergo primum praeceptum legis, quod bonum est faciendum et prosequendum, et malum vitandum. Et super hoc fundantur omnia alia praecepta legis naturae, ut scilicet omnia illa facienda vel vitanda pertineant ad praecepta legis naturae, quae ratio practica naturaliter apprehendit esse bona humana. Quia vero bonum habet rationem finis, malum autem rationem contrarii, inde est quod omnia illa ad quae homo habet naturalem inclinationem, ratio naturaliter apprehendit ut bona, et per consequens ut opere prosequenda, et contraria eorum ut mala et vitanda. Secundum igitur ordinem inclinationum naturalium, est ordo praeceptorum legis naturae. Inest enim primo inclinatio homini ad bonum secundum naturam in qua communicat cum omnibus substantiis, prout scilicet quaelibet substantia appetit conservationem sui esse secundum suam naturam. Et secundum hanc inclinationem, pertinent ad legem naturalem ea per quae vita hominis conservatur, et contrarium impeditur. Secundo inest homini inclinatio ad aliqua magis specialia, secundum naturam in qua communicat cum ceteris animalibus. Et secundum hoc, dicuntur ea esse de lege naturali quae natura omnia animalia docuit, ut est coniunctio maris et feminae, et educatio liberorum, et similia. Tertio modo inest homini inclinatio ad bonum secundum naturam rationis, quae est sibi propria, sicut homo habet naturalem inclinationem ad hoc quod veritatem cognoscat de Deo, et ad hoc quod in societate vivat. Et secundum hoc, ad legem naturalem pertinent ea quae ad huiusmodi inclinationem spectant, utpote quod homo ignorantiam vitet, quod alios non offendat cum quibus debet conversari, et cetera huiusmodi quae ad hoc spectant.

Reply to Objection 1. All these precepts of the law of nature have the character of one natural law, inasmuch as they flow from one first precept.

q. 94 a. 2 ad 1 Ad primum ergo dicendum quod omnia ista praecepta legis naturae, inquantum referuntur ad unum primum praeceptum, habent rationem unius legis naturalis.

Reply to Objection 2. All the inclinations of any parts whatsoever of human nature, e.g. of the concupiscible and irascible parts, in so far as they are ruled by reason, belong to the natural law, and are reduced to one first precept, as stated above: so that the precepts of the natural law are many in themselves, but are based on one common foundation.

q. 94 a. 2 ad 2 Ad secundum dicendum quod omnes inclinationes quarumcumque partium humanae naturae, puta concupiscibilis et irascibilis, secundum quod regulantur ratione, pertinent ad legem naturalem, et reducuntur ad unum primum praeceptum, ut dictum est. Et secundum hoc, sunt multa praecepta legis naturae in seipsis, quae tamen communicant in una radice.

Reply to Objection 3. Although reason is one in itself, yet it directs all things regarding man; so that whatever can be ruled by reason, is contained under the law of reason.

q. 94 a. 2 ad 3 Ad tertium dicendum quod ratio, etsi in se una sit, tamen est ordinativa omnium quae ad homines spectant. Et secundum hoc, sub lege rationis continentur omnia ea quae ratione regulari possunt.

Objection 1. It would seem that not all acts of virtue are prescribed by the natural law. Because, as stated above (Question 90, Article 2) it is essential to a law that it be ordained to the common good. But some acts of virtue are ordained to the private good of the individual, as is evident especially in regards to acts of temperance. Therefore not all acts of virtue are the subject of natural law.

q. 94 a. 3 arg. 1 Ad tertium sic proceditur. Videtur quod non omnes actus virtutum sint de lege naturae. Quia, ut supra dictum est, de ratione legis est ut ordinetur ad bonum commune. Sed quidam virtutum actus ordinantur ad bonum privatum alicuius, ut patet praecipue in actibus temperantiae. Non ergo omnes actus virtutum legi subduntur naturali.

Objection 2. Further, every sin is opposed to some virtuous act. If therefore all acts of virtue are prescribed by the natural law, it seems to follow that all sins are against nature: whereas this applies to certain special sins.

q. 94 a. 3 arg. 2 Praeterea, omnia peccata aliquibus virtuosis actibus opponuntur. Si igitur omnes actus virtutum sint de lege naturae, videtur ex consequenti quod omnia peccata sint contra naturam. Quod tamen specialiter de quibusdam peccatis dicitur.

Objection 3. Further, those things which are according to nature are common to all. But acts of virtue are not common to all: since a thing is virtuous in one, and vicious in another. Therefore not all acts of virtue are prescribed by the natural law.

q. 94 a. 3 arg. 3 Praeterea, in his quae sunt secundum naturam, omnes conveniunt. Sed in actibus virtutum non omnes conveniunt, aliquid enim est virtuosum uni, quod est alteri vitiosum. Ergo non omnes actus virtutum sunt de lege naturae.

On the contrary, Damascene says (De Fide Orth. iii, 4) that “virtues are natural.” Therefore virtuous acts also are a subject of the natural law.

q. 94 a. 3 s. c. Sed contra est quod Damascenus dicit, in III libro, quod virtutes sunt naturales. Ergo et actus virtuosi subiacent legi naturae.

I answer that, We may speak of virtuous acts in two ways: first, under the aspect of virtuous; secondly, as such and such acts considered in their proper species. If then we speak of acts of virtue, considered as virtuous, thus all virtuous acts belong to the natural law. For it has been stated (2) that to the natural law belongs everything to which a man is inclined according to his nature. Now each thing is inclined naturally to an operation that is suitable to it according to its form: thus fire is inclined to give heat. Wherefore, since the rational soul is the proper form of man, there is in every man a natural inclination to act according to reason: and this is to act according to virtue. Consequently, considered thus, all acts of virtue are prescribed by the natural law: since each one’s reason naturally dictates to him to act virtuously. But if we speak of virtuous acts, considered in themselves, i.e. in their proper species, thus not all virtuous acts are prescribed by the natural law: for many things are done virtuously, to which nature does not incline at first; but which, through the inquiry of reason, have been found by men to be conducive to well-living.

q. 94 a. 3 co. Respondeo dicendum quod de actibus virtuosis dupliciter loqui possumus, uno modo, inquantum sunt virtuosi; alio modo, inquantum sunt tales actus in propriis speciebus considerati. Si igitur loquamur de actibus virtutum inquantum sunt virtuosi, sic omnes actus virtuosi pertinent ad legem naturae. Dictum est enim quod ad legem naturae pertinet omne illud ad quod homo inclinatur secundum suam naturam. Inclinatur autem unumquodque naturaliter ad operationem sibi convenientem secundum suam formam, sicut ignis ad calefaciendum. Unde cum anima rationalis sit propria forma hominis, naturalis inclinatio inest cuilibet homini ad hoc quod agat secundum rationem. Et hoc est agere secundum virtutem. Unde secundum hoc, omnes actus virtutum sunt de lege naturali, dictat enim hoc naturaliter unicuique propria ratio, ut virtuose agat. Sed si loquamur de actibus virtuosis secundum seipsos, prout scilicet in propriis speciebus considerantur, sic non omnes actus virtuosi sunt de lege naturae. Multa enim secundum virtutem fiunt, ad quae natura non primo inclinat; sed per rationis inquisitionem ea homines adinvenerunt, quasi utilia ad bene vivendum.

Reply to Objection 1. Temperance is about the natural concupiscences of food, drink and sexual matters, which are indeed ordained to the natural common good, just as other matters of law are ordained to the moral common good.

q. 94 a. 3 ad 1 Ad primum ergo dicendum quod temperantia est circa concupiscentias naturales cibi et potus et venereorum, quae quidem ordinantur ad bonum commune naturae, sicut et alia legalia ordinantur ad bonum commune morale.

Reply to Objection 2. By human nature we may mean either that which is proper to man--and in this sense all sins, as being against reason, are also against nature, as Damascene states (De Fide Orth. ii, 30): or we may mean that nature which is common to man and other animals; and in this sense, certain special sins are said to be against nature; thus contrary to sexual intercourse, which is natural to all animals, is unisexual lust, which has received the special name of the unnatural crime.

q. 94 a. 3 ad 2 Ad secundum dicendum quod natura hominis potest dici vel illa quae est propria homini, et secundum hoc, omnia peccata, inquantum sunt contra rationem, sunt etiam contra naturam, ut patet per Damascenum, in II libro. Vel illa quae est communis homini et aliis animalibus, et secundum hoc, quaedam specialia peccata dicuntur esse contra naturam; sicut contra commixtionem maris et feminae, quae est naturalis omnibus animalibus, est concubitus masculorum, quod specialiter dicitur vitium contra naturam.

Reply to Objection 3. This argument considers acts in themselves. For it is owing to the various conditions of men, that certain acts are virtuous for some, as being proportionate and becoming to them, while they are vicious for others, as being out of proportion to them.

q. 94 a. 3 ad 3 Ad tertium dicendum quod ratio illa procedit de actibus secundum seipsos consideratis. Sic enim, propter diversas hominum conditiones, contingit quod aliqui actus sunt aliquibus virtuosi, tanquam eis proportionati et convenientes, qui tamen sunt aliis vitiosi, tanquam eis non proportionati.

Objection 1. It would seem that the natural law is not the same in all. For it is stated in the Decretals (Dist. i) that “the natural law is that which is contained in the Law and the Gospel.” But this is not common to all men; because, as it is written (Romans 10:16), “all do not obey the gospel.” Therefore the natural law is not the same in all men.

q. 94 a. 4 arg. 1 Ad quartum sic proceditur. Videtur quod lex naturae non sit una apud omnes. Dicitur enim in decretis, dist. I, quod ius naturale est quod in lege et in Evangelio continetur. Sed hoc non est commune omnibus, quia, ut dicitur Rom. X, non omnes obediunt Evangelio. Ergo lex naturalis non est una apud omnes.

Objection 2. Further, “Things which are according to the law are said to be just,” as stated in Ethic. v. But it is stated in the same book that nothing is so universally just as not to be subject to change in regard to some men. Therefore even the natural law is not the same in all men.

q. 94 a. 4 arg. 2 Praeterea, ea quae sunt secundum legem, iusta esse dicuntur, ut dicitur in V Ethic. Sed in eodem libro dicitur quod nihil est ita iustum apud omnes, quin apud aliquos diversificetur. Ergo lex etiam naturalis non est apud omnes eadem.

Objection 3. Further, as stated above (2,3), to the natural law belongs everything to which a man is inclined according to his nature. Now different men are naturally inclined to different things; some to the desire of pleasures, others to the desire of honors, and other men to other things. Therefore there is not one natural law for all.

q. 94 a. 4 arg. 3 Praeterea, ad legem naturae pertinet id ad quod homo secundum naturam suam inclinatur, ut supra dictum est. Sed diversi homines naturaliter ad diversa inclinantur, alii quidem ad concupiscentiam voluptatum, alii ad desideria honorum, alii ad alia. Ergo non est una lex naturalis apud omnes.

On the contrary, Isidore says (Etym. v, 4): “The natural law is common to all nations.”

q. 94 a. 4 s. c. Sed contra est quod Isidorus dicit, in libro Etymol., ius naturale est commune omnium nationum.

I answer that, As stated above (2,3), to the natural law belongs those things to which a man is inclined naturally: and among these it is proper to man to be inclined to act according to reason. Now the process of reason is from the common to the proper, as stated in Phys. i. The speculative reason, however, is differently situated in this matter, from the practical reason. For, since the speculative reason is busied chiefly with the necessary things, which cannot be otherwise than they are, its proper conclusions, like the universal principles, contain the truth without fail. The practical reason, on the other hand, is busied with contingent matters, about which human actions are concerned: and consequently, although there is necessity in the general principles, the more we descend to matters of detail, the more frequently we encounter defects. Accordingly then in speculative matters truth is the same in all men, both as to principles and as to conclusions: although the truth is not known to all as regards the conclusions, but only as regards the principles which are called common notions. But in matters of action, truth or practical rectitude is not the same for all, as to matters of detail, but only as to the general principles: and where there is the same rectitude in matters of detail, it is not equally known to all. It is therefore evident that, as regards the general principles whether of speculative or of practical reason, truth or rectitude is the same for all, and is equally known by all. As to the proper conclusions of the speculative reason, the truth is the same for all, but is not equally known to all: thus it is true for all that the three angles of a triangle are together equal to two right angles, although it is not known to all. But as to the proper conclusions of the practical reason, neither is the truth or rectitude the same for all, nor, where it is the same, is it equally known by all. Thus it is right and true for all to act according to reason: and from this principle it follows as a proper conclusion, that goods entrusted to another should be restored to their owner. Now this is true for the majority of cases: but it may happen in a particular case that it would be injurious, and therefore unreasonable, to restore goods held in trust; for instance, if they are claimed for the purpose of fighting against one’s country. And this principle will be found to fail the more, according as we descend further into detail, e.g. if one were to say that goods held in trust should be restored with such and such a guarantee, or in such and such a way; because the greater the number of conditions added, the greater the number of ways in which the principle may fail, so that it be not right to restore or not to restore. Consequently we must say that the natural law, as to general principles, is the same for all, both as to rectitude and as to knowledge. But as to certain matters of detail, which are conclusions, as it were, of those general principles, it is the same for all in the majority of cases, both as to rectitude and as to knowledge; and yet in some few cases it may fail, both as to rectitude, by reason of certain obstacles (just as natures subject to generation and corruption fail in some few cases on account of some obstacle), and as to knowledge, since in some the reason is perverted by passion, or evil habit, or an evil disposition of nature; thus formerly, theft, although it is expressly contrary to the natural law, was not considered wrong among the Germans, as Julius Caesar relates (De Bello Gall. vi).

q. 94 a. 4 co. Respondeo dicendum quod, sicut supra dictum est, ad legem naturae pertinent ea ad quae homo naturaliter inclinatur; inter quae homini proprium est ut inclinetur ad agendum secundum rationem. Ad rationem autem pertinet ex communibus ad propria procedere, ut patet ex I Physic. Aliter tamen circa hoc se habet ratio speculativa, et aliter ratio practica. Quia enim ratio speculativa praecipue negotiatur circa necessaria, quae impossibile est aliter se habere, absque aliquo defectu invenitur veritas in conclusionibus propriis, sicut et in principiis communibus. Sed ratio practica negotiatur circa contingentia, in quibus sunt operationes humanae, et ideo, etsi in communibus sit aliqua necessitas, quanto magis ad propria descenditur, tanto magis invenitur defectus. Sic igitur in speculativis est eadem veritas apud omnes tam in principiis quam in conclusionibus, licet veritas non apud omnes cognoscatur in conclusionibus, sed solum in principiis, quae dicuntur communes conceptiones. In operativis autem non est eadem veritas vel rectitudo practica apud omnes quantum ad propria, sed solum quantum ad communia, et apud illos apud quos est eadem rectitudo in propriis, non est aequaliter omnibus nota. Sic igitur patet quod, quantum ad communia principia rationis sive speculativae sive practicae, est eadem veritas seu rectitudo apud omnes, et aequaliter nota. Quantum vero ad proprias conclusiones rationis speculativae, est eadem veritas apud omnes, non tamen aequaliter omnibus nota, apud omnes enim verum est quod triangulus habet tres angulos aequales duobus rectis, quamvis hoc non sit omnibus notum. Sed quantum ad proprias conclusiones rationis practicae, nec est eadem veritas seu rectitudo apud omnes; nec etiam apud quos est eadem, est aequaliter nota. Apud omnes enim hoc rectum est et verum, ut secundum rationem agatur. Ex hoc autem principio sequitur quasi conclusio propria, quod deposita sint reddenda. Et hoc quidem ut in pluribus verum est, sed potest in aliquo casu contingere quod sit damnosum, et per consequens irrationabile, si deposita reddantur; puta si aliquis petat ad impugnandam patriam. Et hoc tanto magis invenitur deficere, quanto magis ad particularia descenditur, puta si dicatur quod deposita sunt reddenda cum tali cautione, vel tali modo, quanto enim plures conditiones particulares apponuntur, tanto pluribus modis poterit deficere, ut non sit rectum vel in reddendo vel in non reddendo. Sic igitur dicendum est quod lex naturae, quantum ad prima principia communia, est eadem apud omnes et secundum rectitudinem, et secundum notitiam. Sed quantum ad quaedam propria, quae sunt quasi conclusiones principiorum communium, est eadem apud omnes ut in pluribus et secundum rectitudinem et secundum notitiam, sed ut in paucioribus potest deficere et quantum ad rectitudinem, propter aliqua particularia impedimenta (sicut etiam naturae generabiles et corruptibiles deficiunt ut in paucioribus, propter impedimenta), et etiam quantum ad notitiam; et hoc propter hoc quod aliqui habent depravatam rationem ex passione, seu ex mala consuetudine, seu ex mala habitudine naturae; sicut apud germanos olim latrocinium non reputabatur iniquum, cum tamen sit expresse contra legem naturae, ut refert Iulius Caesar, in libro de bello Gallico.

Reply to Objection 1. The meaning of the sentence quoted is not that whatever is contained in the Law and the Gospel belongs to the natural law, since they contain many things that are above nature; but that whatever belongs to the natural law is fully contained in them. Wherefore Gratian, after saying that “the natural law is what is contained in the Law and the Gospel,” adds at once, by way of example, “by which everyone is commanded to do to others as he would be done by.”

q. 94 a. 4 ad 1 Ad primum ergo dicendum quod verbum illud non est sic intelligendum quasi omnia quae in lege et in Evangelio continentur, sint de lege naturae, cum multa tradantur ibi supra naturam, sed quia ea quae sunt de lege naturae, plenarie ibi traduntur. Unde cum dixisset Gratianus quod ius naturale est quod in lege et in Evangelio continetur, statim, exemplificando, subiunxit, quo quisque iubetur alii facere quod sibi vult fieri.

Reply to Objection 2. The saying of the Philosopher is to be understood of things that are naturally just, not as general principles, but as conclusions drawn from them, having rectitude in the majority of cases, but failing in a few.

q. 94 a. 4 ad 2 Ad secundum dicendum quod verbum philosophi est intelligendum de his quae sunt naturaliter iusta non sicut principia communia, sed sicut quaedam conclusiones ex his derivatae; quae ut in pluribus rectitudinem habent, et ut in paucioribus deficiunt.

Reply to Objection 3. As, in man, reason rules and commands the other powers, so all the natural inclinations belonging to the other powers must needs be directed according to reason. Wherefore it is universally right for all men, that all their inclinations should be directed according to reason.

q. 94 a. 4 ad 3 Ad tertium dicendum quod, sicut ratio in homine dominatur et imperat aliis potentiis, ita oportet quod omnes inclinationes naturales ad alias potentias pertinentes ordinentur secundum rationem. Unde hoc est apud omnes communiter rectum, ut secundum rationem dirigantur omnes hominum inclinationes.

Objection 1. It would seem that the natural law can be changed. Because on Sirach 17:9, “He gave them instructions, and the law of life,” the gloss says: “He wished the law of the letter to be written, in order to correct the law of nature.” But that which is corrected is changed. Therefore the natural law can be changed.

q. 94 a. 5 arg. 1 Ad quintum sic proceditur. Videtur quod lex naturae mutari possit. Quia super illud Eccli. XVII, addidit eis disciplinam et legem vitae, dicit Glossa, legem litterae, quantum ad correctionem legis naturalis, scribi voluit. Sed illud quod corrigitur, mutatur. Ergo lex naturalis potest mutari.

Objection 2. Further, the slaying of the innocent, adultery, and theft are against the natural law. But we find these things changed by God: as when God commanded Abraham to slay his innocent son (Genesis 22:2); and when he ordered the Jews to borrow and purloin the vessels of the Egyptians (Exodus 12:35); and when He commanded Osee to take to himself “a wife of fornications” (Hosea 1:2). Therefore the natural law can be changed.

q. 94 a. 5 arg. 2 Praeterea, contra legem naturalem est occisio innocentis, et etiam adulterium et furtum. Sed ista inveniuntur esse mutata a Deo, puta cum Deus praecepit Abrahae quod occideret filium innocentem, ut habetur Gen. XXII; et cum praecepit Iudaeis ut mutuata Aegyptiorum vasa subriperent, ut habetur Exod. XII; et cum praecepit Osee ut uxorem fornicariam acciperet, ut habetur Osee I. Ergo lex naturalis potest mutari.

Objection 3. Further, Isidore says (Etym. 5:4) that “the possession of all things in common, and universal freedom, are matters of natural law.” But these things are seen to be changed by human laws. Therefore it seems that the natural law is subject to change.

q. 94 a. 5 arg. 3 Praeterea, Isidorus dicit, in libro Etymol., quod communis omnium possessio, et una libertas, est de iure naturali. Sed haec videmus esse commutata per leges humanas. Ergo videtur quod lex naturalis sit mutabilis.

On the contrary, It is said in the Decretals (Dist. v): “The natural law dates from the creation of the rational creature. It does not vary according to time, but remains unchangeable.”

q. 94 a. 5 s. c. Sed contra est quod dicitur in decretis, dist. V, naturale ius ab exordio rationalis creaturae. Nec variatur tempore, sed immutabile permanet.

I answer that, A change in the natural law may be understood in two ways. First, by way of addition. In this sense nothing hinders the natural law from being changed: since many things for the benefit of human life have been added over and above the natural law, both by the Divine law and by human laws. Secondly, a change in the natural law may be understood by way of subtraction, so that what previously was according to the natural law, ceases to be so. In this sense, the natural law is altogether unchangeable in its first principles: but in its secondary principles, which, as we have said (4), are certain detailed proximate conclusions drawn from the first principles, the natural law is not changed so that what it prescribes be not right in most cases. But it may be changed in some particular cases of rare occurrence, through some special causes hindering the observance of such precepts, as stated above (Article 4).

q. 94 a. 5 co. Respondeo dicendum quod lex naturalis potest intelligi mutari dupliciter. Uno modo, per hoc quod aliquid ei addatur. Et sic nihil prohibet legem naturalem mutari, multa enim supra legem naturalem superaddita sunt, ad humanam vitam utilia, tam per legem divinam, quam etiam per leges humanas. Alio modo intelligitur mutatio legis naturalis per modum subtractionis, ut scilicet aliquid desinat esse de lege naturali, quod prius fuit secundum legem naturalem. Et sic quantum ad prima principia legis naturae, lex naturae est omnino immutabilis. Quantum autem ad secunda praecepta, quae diximus esse quasi quasdam proprias conclusiones propinquas primis principiis, sic lex naturalis non immutatur quin ut in pluribus rectum sit semper quod lex naturalis habet. Potest tamen immutari in aliquo particulari, et in paucioribus, propter aliquas speciales causas impedientes observantiam talium praeceptorum, ut supra dictum est.

Reply to Objection 1. The written law is said to be given for the correction of the natural law, either because it supplies what was wanting to the natural law; or because the natural law was perverted in the hearts of some men, as to certain matters, so that they esteemed those things good which are naturally evil; which perversion stood in need of correction.

q. 94 a. 5 ad 1 Ad primum ergo dicendum quod lex scripta dicitur esse data ad correctionem legis naturae, vel quia per legem scriptam suppletum est quod legi naturae deerat, vel quia lex naturae in aliquorum cordibus, quantum ad aliqua, corrupta erat intantum ut existimarent esse bona quae naturaliter sunt mala; et talis corruptio correctione indigebat.

Reply to Objection 2. All men alike, both guilty and innocent, die the death of nature: which death of nature is inflicted by the power of God on account of original sin, according to 1 Samuel 2:6: “The Lord killeth and maketh alive.” Consequently, by the command of God, death can be inflicted on any man, guilty or innocent, without any injustice whatever. In like manner adultery is intercourse with another’s wife; who is allotted to him by the law emanating from God. Consequently intercourse with any woman, by the command of God, is neither adultery nor fornication. The same applies to theft, which is the taking of another’s property. For whatever is taken by the command of God, to Whom all things belong, is not taken against the will of its owner, whereas it is in this that theft consists. Nor is it only in human things, that whatever is commanded by God is right; but also in natural things, whatever is done by God, is, in some way, natural, as stated in the I, 105, 6, ad 1.

q. 94 a. 5 ad 2 Ad secundum dicendum quod naturali morte moriuntur omnes communiter, tam nocentes quam innocentes. Quae quidem naturalis mors divina potestate inducitur propter peccatum originale; secundum illud I Reg. II, dominus mortificat et vivificat. Et ideo absque aliqua iniustitia, secundum mandatum Dei, potest infligi mors cuicumque homini, vel nocenti vel innocenti. Similiter etiam adulterium est concubitus cum uxore aliena, quae quidem est ei deputata secundum legem divinitus traditam. Unde ad quamcumque mulierem aliquis accedat ex mandato divino, non est adulterium nec fornicatio. Et eadem ratio est de furto, quod est acceptio rei alienae. Quidquid enim accipit aliquis ex mandato Dei, qui est dominus universorum, non accipit absque voluntate domini, quod est furari. Nec solum in rebus humanis quidquid a Deo mandatur, hoc ipso est debitum, sed etiam in rebus naturalibus quidquid a Deo fit, est quodammodo naturale, ut in primo dictum est.

Reply to Objection 3. A thing is said to belong to the natural law in two ways. First, because nature inclines thereto: e.g. that one should not do harm to another. Secondly, because nature did not bring in the contrary: thus we might say that for man to be naked is of the natural law, because nature did not give him clothes, but art invented them. In this sense, “the possession of all things in common and universal freedom” are said to be of the natural law, because, to wit, the distinction of possessions and slavery were not brought in by nature, but devised by human reason for the benefit of human life. Accordingly the law of nature was not changed in this respect, except by addition.

q. 94 a. 5 ad 3 Ad tertium dicendum quod aliquid dicitur esse de iure naturali dupliciter. Uno modo, quia ad hoc natura inclinat, sicut non esse iniuriam alteri faciendam. Alio modo, quia natura non induxit contrarium, sicut possemus dicere quod hominem esse nudum est de iure naturali, quia natura non dedit ei vestitum, sed ars adinvenit. Et hoc modo communis omnium possessio, et omnium una libertas, dicitur esse de iure naturali, quia scilicet distinctio possessionum et servitus non sunt inductae a natura, sed per hominum rationem, ad utilitatem humanae vitae. Et sic in hoc lex naturae non est mutata nisi per additionem.

Objection 1. It would seem that the natural law can be abolished from the heart of man. Because on Romans 2:14, “When the Gentiles who have not the law,” etc. a gloss says that “the law of righteousness, which sin had blotted out, is graven on the heart of man when he is restored by grace.” But the law of righteousness is the law of nature. Therefore the law of nature can be blotted out.

q. 94 a. 6 arg. 1 Ad sextum sic proceditur. Videtur quod lex naturae possit a corde hominis aboleri. Quia Rom. II, super illud, cum gentes, quae legem non habent, etc., dicit Glossa quod in interiori homine per gratiam innovato, lex iustitiae inscribitur, quam deleverat culpa. Sed lex iustitiae est lex naturae. Ergo lex naturae potest deleri.

Objection 2. Further, the law of grace is more efficacious than the law of nature. But the law of grace is blotted out by sin. Much more therefore can the law of nature be blotted out.

q. 94 a. 6 arg. 2 Praeterea, lex gratiae est efficacior quam lex naturae. Sed lex gratiae deletur per culpam. Ergo multo magis lex naturae potest deleri.

Objection 3. Further, that which is established by law is made just. But many things are enacted by men, which are contrary to the law of nature. Therefore the law of nature can be abolished from the heart of man.

q. 94 a. 6 arg. 3 Praeterea, illud quod lege statuitur, inducitur quasi iustum. Sed multa sunt ab hominibus statuta contra legem naturae. Ergo lex naturae potest a cordibus hominum aboleri.

On the contrary, Augustine says (Confess. ii): “Thy law is written in the hearts of men, which iniquity itself effaces not.” But the law which is written in men’s hearts is the natural law. Therefore the natural law cannot be blotted out.

q. 94 a. 6 s. c. Sed contra est quod Augustinus dicit, in II Confess., lex tua scripta est in cordibus hominum, quam nec ulla quidem delet iniquitas. Sed lex scripta in cordibus hominum est lex naturalis. Ergo lex naturalis deleri non potest.

I answer that, As stated above (4,5), there belong to the natural law, first, certain most general precepts, that are known to all; and secondly, certain secondary and more detailed precepts, which are, as it were, conclusions following closely from first principles. As to those general principles, the natural law, in the abstract, can nowise be blotted out from men’s hearts. But it is blotted out in the case of a particular action, in so far as reason is hindered from applying the general principle to a particular point of practice, on account of concupiscence or some other passion, as stated above (Question 77, Article 2). But as to the other, i.e. the secondary precepts, the natural law can be blotted out from the human heart, either by evil persuasions, just as in speculative matters errors occur in respect of necessary conclusions; or by vicious customs and corrupt habits, as among some men, theft, and even unnatural vices, as the Apostle states (Romans 1), were not esteemed sinful.

q. 94 a. 6 co. Respondeo dicendum quod, sicut supra dictum est, ad legem naturalem pertinent primo quidem quaedam praecepta communissima, quae sunt omnibus nota, quaedam autem secundaria praecepta magis propria, quae sunt quasi conclusiones propinquae principiis. Quantum ergo ad illa principia communia, lex naturalis nullo modo potest a cordibus hominum deleri in universali. Deletur tamen in particulari operabili, secundum quod ratio impeditur applicare commune principium ad particulare operabile, propter concupiscentiam vel aliquam aliam passionem, ut supra dictum est. Quantum vero ad alia praecepta secundaria, potest lex naturalis deleri de cordibus hominum, vel propter malas persuasiones, eo modo quo etiam in speculativis errores contingunt circa conclusiones necessarias; vel etiam propter pravas consuetudines et habitus corruptos; sicut apud quosdam non reputabantur latrocinia peccata, vel etiam vitia contra naturam, ut etiam apostolus dicit, ad Rom. I.

Reply to Objection 1. Sin blots out the law of nature in particular cases, not universally, except perchance in regard to the secondary precepts of the natural law, in the way stated above.

q. 94 a. 6 ad 1 Ad primum ergo dicendum quod culpa delet legem naturae in particulari, non autem in universali, nisi forte quantum ad secunda praecepta legis naturae, eo modo quo dictum est.

Reply to Objection 2. Although grace is more efficacious than nature, yet nature is more essential to man, and therefore more enduring.

q. 94 a. 6 ad 2 Ad secundum dicendum quod gratia etsi sit efficacior quam natura, tamen natura essentialior est homini, et ideo magis permanens.

Reply to Objection 3. This argument is true of the secondary precepts of the natural law, against which some legislators have framed certain enactments which are unjust.

q. 94 a. 6 ad 3 Ad tertium dicendum quod ratio illa procedit de secundis praeceptis legis naturae, contra quae aliqui legislatores statuta aliqua fecerunt, quae sunt iniqua.