Summa Theologiae Moralis, vol. I: De Principiis

S. Th. I-II, q. 94, a. 2 and 3 ; q. 100, a. 1.

250. Natural law is one, containing several precepts. — Natural law, although with respect to the matter about which it is concerned it contains several precepts, is nevertheless in itself one, both because it tends to one ultimate end, and because all those precepts are founded on one first universal principle : Good is to be done, evil is to be avoided.

It is proved : Human reason, both speculative and practical, is essentially deductive. But just as being is the first thing known by the intellect, so good is the first thing known by practical reason. Whence just as the first speculative principle is founded on the notion of being : It is impossible for the same thing to be and not to be, so the first practical principle is founded on the notion of good : Good is to be done, evil avoided ; and therefore reason prescribes or forbids nothing except what it naturally apprehends as good or evil¹.

251. Order and division of the precepts. — Natural law in a general way comprises all those things which so befit or are repugnant to rational nature that for the preservation of order they must necessarily be prescribed or forbidden by the very Creator of nature²; whence there pertain to natural law all the precepts to which by the nature of the thing and independently of any positive law we are obliged. Among which there is a manifold order :

A. By reason of matter, in a twofold way : a) according to the threefold natural inclination of man to the good, whether of natural being, i.e. the preservation of existence, or of animal life, e.g. the procreation of offspring, or of rational life proper to himself.

For good has the character of an end, whence man has as goods all those things to which he has a natural inclination. But there is in man a threefold inclination : 1) to the good according to the nature which he has in common with all substances, which all seek the preservation of their being ; 2) to the good according to the nature which he has in common with animals, such as procreation and education of offspring ; 3) to the good according to the nature of reason, which are proper to him, e.g. that he worship God and live in society.

Hence the precepts are distinguished according to the nature of substance (abstinence, fortitude), according to the nature of animal (chastity, prudence), and according to the nature of man (religion, justice) ;

b) according to the threefold natural relation or order of man : 1) to God as to his first principle and ultimate end ; — 2) to himself : for he is made up of two parts, of which the higher must rule the lower ; — 3) to his neighbor : born social, man is destined for conjugal, domestic, and political society. Hence the precepts are distinguished into those toward God, toward himself, and toward his neighbor, according as man is considered as a created, rational, or social being.

The order to God is the order of subjection ; the order to one's neighbor is the order of equality and proximity, by which his person in himself or in his goods is forbidden to be violated, and he himself is to be loved after our own likeness ; the order of man to himself is the order of conformity of himself and of his faculties (of which he is not the master) to reason and to rational nature and its proper end, and of subordination to the human species and the common good.

B. Formally, on the part of the manner in which they are contained in law, or by reason of the knowledge and logical nexus between the principles of natural law :

1. some are general, most universal, most common, indeterminate, evident in themselves, known to all from the mere understanding of the terms, e.g. Good is to be done, evil is to be avoided ; What you do not wish to be done to you, do not do to another ; One is to live according to reason ; The Creator is to be obeyed ; To each his own is to be rendered ; The Supreme Good is to be loved ; Injury is to be done to no one ; Live conformably to your nature as a rational, created, social being, etc.

2. others are more proper and determinate, particular, as conclusions deduced from the first, and these are

a) either immediately, proximately and evidently deduced from the first, which are the precepts of the decalogue ; or

b) more remote, which are not so evidently but mediately and by many consequences deduced, e.g. that usury is unjust, that lying is always illicit, that injury inflicted is not to be vindicated by one's own authority, that things found are to be restored.

C. By reason of force and efficacy, or necessity for the end, and the ontological and real nexus :

1. some precepts are primarily intended, which nature altogether requires, because they are altogether necessary for the end which nature directly and principally intends : thus matrimony is altogether necessary for the due procreation and education of offspring ;

2. others are secondarily intended, derived from the first, to which nature much inclines, which are either necessary, not indeed in order that the primary end be obtained, but in order that it be obtained becomingly, suitably, more easily, or are necessary for a secondary end which nature does not directly but concomitantly and subordinately to another intend : thus the unity of matrimony befits the education of offspring and is necessary for family peace.

Briefly : some precepts are about things necessary without which the moral order is impossible ; others, about very useful things, which are not strictly necessary, so that the order without them, although less perfectly, can subsist³.

Hence with relation to the altogether ultimate and primary end of natural law, which is God and the love of God above all things, are distinguished

a) first precepts, which strictly necessary for the love of God prescribe, or forbid those things that directly hinder it and turn away from it ; of which

1. some immediately state the necessary order, or repugnance, to the ultimate end, God : these are the precepts of the first table ;

2. others immediately state the necessary order, or repugnance, to the love of ourselves or of our neighbor, yet mediately to the ultimate end, inasmuch as they are means by the nature of the thing necessary for it : the love of ourselves indeed, because it is a necessary predisposition to the love of God and of our neighbor, since we can tend only to our own good, nor love anyone except by imitating the love of ourselves, and because our life is a necessary condition for the attainment of the end ; the love of our neighbor, because society is a medium altogether necessary by the nature of the thing for men to obtain the end, whence those that are necessary for society without which it cannot subsist pertain here : these are the precepts of the second table.

All of which are prescribed or forbidden gravely, as altogether necessary for the ultimate end or altogether opposed to it ;

b) second precepts derived from the first, which prescribe those things that are necessary in order that the end be obtained becomingly, better, more easily, and forbid those things that retard it or cannot be referred to it, such as are 1) those that include a certain small irreverence toward God, and only fall short of the due manner of worship ; 2) those that somewhat detract from justice or charity ; or 3) those that only lack necessity or utility. These are prescribed or forbidden lightly, because they are not strictly necessary for the ultimate end nor turn away from it⁴.

From the foregoing it is clear that the primary or secondary in cognition and the primary or secondary in necessity and intention of nature are not the same precepts ; for many secondary in cognition which are deduced from the first principles by conclusions (even remote) are primarily intended by nature, as the prohibition of homicide, adultery, theft ; hence one must well observe in what sense those terms are used by authors.

252. The object of natural law are the acts of the virtues. — The acts of the virtues, according to genus, inasmuch as they are virtuous, all are of natural law : for this comprises all things to which man is inclined according to nature. But each thing is inclined to the operation befitting its form ; now the form of man is the rational soul. Whence man is naturally inclined to operate according to reason, which is to act according to virtue. — If however virtuous acts are considered in themselves, inasmuch as they are such and such, according to species, not all are of natural law, because many are of counsel, or of those things to which nature does not incline, but which men have discovered by the inquiry of reason as useful for living well.

253. The subject of natural law. — Because natural law is implanted with rational nature and essentially conjoined to it, hence all rational creatures are subject to it and bound by it, not only adults (among whom the blessed and the damned), but also children and those permanently demented : these however not perfectly and in the second act, because they do not have the use of reason and knowledge of the law, but imperfectly and in the first act, because they have the potency for these. Hence

1. although in these there is no formal sin because the use of reason and of liberty is lacking, they nevertheless sin materially, by acting against the law of nature inherently in them habitually ;

2. the same is to be said of those sleeping, drunk, and others who here and now are ignorant of the law, unless however they have culpably placed the cause of sin, in which case they also sin formally ;

3. those who induce the aforesaid to act against natural law sin formally : for they are the moral or even physical cause of these sins, and therefore by their will they participate in and embrace them : for the action of the instrument is rightly imputed to the principal agent. Add that they are often the cause of evil custom in those, and of scandal in those standing by.

S. Th. C. Gent. III, 140-141.

254. Notions. — Sanction a) on the part of cause or origin, is internal (and concomitant), which proceeds naturally and by the very fact, from the very action or from the nature of the thing, following the observance or violation of law, e.g. tranquility and remorse of conscience, good and evil fame, bodily indisposition from drunkenness ; — and external (or inflicted), which comes from an extrinsic cause, or from the disposition of law connecting with the observance or violation of law, e.g. if a drunkard is punished by a judge with a fine ;

b) on the part of effect, is perfect or sufficient, which by its nature is able to move all subjects (whether absolutely, or relatively for certain circumstances) in every case to the observance of the law, and has due proportion with merit and demerit ; — or imperfect and insufficient.

255. Thesis. The sanction of natural law, imperfect and internal, exists in the present life ; — perfect [sanction] is in the other life, from the attainment or loss of the ultimate end.

a) The first part is proved. There is an internal sanction, for virtue is the perfect good of this life ; and fault is more often followed by 1) remorse of conscience, because « the impulse of malice or passion ceasing, by which they do evil, according to reason they know that they have done evil and grieve¹. » ; 2) pain in the soul ; 3) sickness in the body. Whence Wis. XI, 17 : By the things by which one sins, by the same is he also tormented. It is however imperfect, both because it does not sufficiently induce to the observance of the law, for we are sometimes bound to lay down even life itself, and there are many seductions in this life to overcome which there is required a sanction superior to the goods of this life ; and because, as experience witnesses, it does not render to each one according to justice.

b) The second part is proved 1) from the essential order of things : Where there is the due order to an end, the order must lead to that end, and a departure from the order must exclude the end. But by God's disposition and law human acts are essentially ordered to the ultimate end. Therefore those keeping the order must attain the ultimate end (which is to be rewarded) ; but those departing from the order must be excluded from the end (which is to be punished). It is confirmed :

a) As natural things are subject to the ordination of divine providence, so also human nature ; therefore as in natural things the order kept necessarily produces conservation and good in them, so in human things the order of the law divinely imposed, when kept, must by the disposition of the governor lead to the good of retribution, the order of the law, when omitted, to the evil of penalty.

b) For matter does not attain form unless it has been suitably disposed. But the end is the perfection of the will, as form is the perfection of matter. Therefore the will does not attain the end unless it has been suitably disposed. But it is disposed by the intention and desire and pursuit of the end. Therefore he whose intention is turned away from the end will not attain it.

c) Which also holds for the supernatural end. For he who departs from the natural end, also departs from the supernatural end, because the natural order is the foundation of the elevation to the supernatural end. He departs, namely, from God as the principle of every perfection.

2. from the wisdom of the supreme legislator : God, as being a most wise and provident legislator, intends that natural law be observed by all. But, as experience witnesses, one efficacious and necessary means of inducing free men, moved by depraved cupidities and pleasures, to this, is a perfect sanction, so proportioned to every virtue and difficulty of the law that, all things considered, it is never truly useful for a man to depart from the law. Therefore God has established a perfect sanction. But in the present life such a perfect sanction is lacking. Therefore the perfect sanction pertains to the future life, or to the state of the term and end, so that the human will, which naturally tends to happiness, by the hope of this attainment and fear of its loss may be efficaciously moved to the observance of the law.

3. from the sanctity and justice of the supreme lord : Men are distinguished from one another by their acts, to which imputability and merit pertain. But divine sanctity requires that this distinction, resulting from the imputability of human acts, be preserved in the future life ; and justice requires that reward be given for merit, penalty for demerit. Therefore. For, if good and evil with respect to the essential attainment of the end were on a par, there would be no essential distinction of morality, since all morality depends on the relation to the ultimate end ; and so : a) in practice the intrinsic difference between good and evil would be destroyed, and God would seem indifferent to good and evil ; which contradicts his sanctity ; — b) the law of God would be violated with impunity, and the rebellious creature could escape his will and, as it were, triumph over him ; which is repugnant to the justice of the divine lord.

256. Sanction does not harm morality. — For to do good for the sake of reward, to avoid evil for fear of punishment, can happen in a twofold way : a) so that reward or punishment is the sole motive of the act, without any respect to its goodness or malice, and such a manner is evil because it perverts the order, the means being placed before the end ; b) so that one uses the hope of reward or the fear of punishment in order more efficaciously to pursue good and more efficaciously to avoid evil, and such a manner is conformed to the order intended by the legislator who appends sanction as a means of urging the obligation of the law. This is confirmed by the universal practice of parents and teachers in educating children (n. 133, 3).

Hence the Kantian ethics which posited only the motive of obligation is not more perfect than the Christian, which they say is founded on fear and hope. For on the one hand the Christian ethics does not teach that morality depends on fear and hope, but that these are an aid ; on the other hand Kant refuses to admit that rational human nature and the essential order of things are the foundation of morality. And yet ethics does not have the task of correcting nature, but of taking it as it in fact is and of directing human actions so that they are conformed to rational nature².