St. Thomas Aquinas, Summa Theologica, First Part of the Second Part

The “Treatise on Law” Questions:

Question 90. Of the Essence of Law                          103. Of the Duration of the Ceremonial Precepts

91. Of the Various Kinds of Law                               104. Of the Judicial Precepts

92. Of the Effects of Law                                           105. Of the Reason for the Judicial Precepts

93. Of the Eternal Law                                               106. Of the Law of the Gospel, Called the New Law, Considered in Itself

94. Of the Natural Law                                               107. Of the New Law As Compared with the Old

95. Of Human Law                                                     108. Of Those Things That Are Contained in the New Law

96. Of the Power of Human Law                               109. Of the Necessity of Grace

97. Of Change in Laws                                               110. Of the Grace of God As Regards Its Essence

98.  Of the Old Law                                                    111. Of the Division of Grace

99. Of the Precepts of the Old Law                            112. Of the Cause of Grace

100. Of the Moral Precepts of the Old Law               113. Of the Effects of Grace

101. Of the Ceremonial Precepts in Themselves      114. Of Merit

102. Of the Causes of the Ceremonial Precepts 



[* The scholastic format of the Summa Theologica or Summary of Theology (or, "Everything You Ever Wanted to Know about Christian Theology but were Afraid to Ask") of St. Thomas takes some getting used to. The Summa itself is divided into several parts and sub-parts. He then divides the treatise up into numbered Questions. Each numbered question is then divided up into Articles. Each Article is divided into a series of Objections, which turn out to be criticisms of the point that Aquinas ultimately wishes to make, followed by a section headed "On the contrary," which marks the beginning of the argument for St. Thomas's position. Then follows the "I answer that" section, which is the key to St. Thomas's argument, and a series of replies to the initial objections. Focus on the "I answer that" paragraphs and then look at the Objections and their Replies. We will go over this and a few other Questions from the Summa in class. The Questions identified as St. Thomas’s “Treatise on Law” are listed below.]

   We must now consider the various kinds of law: under which head there are six points of inquiry:

    (1) Whether there is an eternal law?

    (2) Whether there is a natural law?

    (3) Whether there is a human law?

    (4) Whether there is a Divine law?

    (5) Whether there is one Divine law, or several? [Omitted]

    (6) Whether there is a law of sin? [Omitted]

Article 1. Whether there is an eternal law?

  Objection 1: It would seem that there is no eternal law. Because every law is imposed on someone. But there was not someone from eternity on whom a law could be imposed: since God alone was from eternity. Therefore no law is eternal.

  Objection 2: Further, promulgation is essential to law. But promulgation could not be from eternity: because there was no one to whom it could be promulgated from eternity. Therefore no law can be eternal.

  Objection 3: Further, a law implies order to an end. But nothing ordained to an end is eternal: for the last end alone is eternal. Therefore no law is eternal.

  On the contrary, Augustine says (De Libero Arbitrio [On the Free Choice of the Will] i, 6): "That Law which is the Supreme Reason cannot be understood to be otherwise than unchangeable and eternal."

  I answer that, As stated above (Question [90], Article [1], ad 2; Articles [3], 4), a law is nothing else but a dictate of practical reason emanating from the ruler who governs a perfect community. Now it is evident, granted that the world is ruled by Divine Providence, as was stated in the FP, Question [22], Articles [1],2, that the whole community of the universe is governed by Divine Reason. Wherefore the very Idea of the government of things in God the Ruler of the universe, has the nature of a law. And since the Divine Reason's conception of things is not subject to time but is eternal, according to Prov. 8:23, therefore it is that this kind of law must be called eternal.

  Reply to Objection 1: Those things that are not in themselves, exist with God, inasmuch as they are foreknown and preordained by Him, according to Rm. 4:17: "Who calls those things that are not, as those that are." Accordingly the eternal concept of the Divine law bears the character of an eternal law, in so far as it is ordained by God to the government of things foreknown by Him.

  Reply to Objection 2: Promulgation is made by word of mouth or in writing; and in both ways the eternal law is promulgated: because both the Divine Word and the writing of the Book of Life are eternal. But the promulgation cannot be from eternity on the part of the creature that hears or reads.

  Reply to Objection 3: The law implies order to the end actively, in so far as it directs certain things to the end; but not passively---that is to say, the law itself is not ordained to the end---except accidentally, in a governor whose end is extrinsic to him, and to which end his law must needs be ordained. But the end of the Divine government is God Himself, and His law is not distinct from Himself. Wherefore the eternal law is not ordained to another end.

Article 2. Whether there is in us a natural law?

  Objection 1: It would seem that there is no natural law in us. Because man is governed sufficiently by the eternal law: for Augustine says (De Lib. Arb. i) that "the eternal law is that by which it is right that all things should be most orderly." But nature does not abound in superfluities as neither does she fail in necessaries. Therefore no law is natural to man.

  Objection 2: Further, by the law man is directed, in his acts, to the end, as stated above (Question [90], Article [2]). But the directing of human acts to their end is not a function of nature, as is the case in irrational creatures, which act for an end solely by their natural appetite; whereas man acts for an end by his reason and will. Therefore no law is natural to man.

  Objection 3: Further, the more a man is free, the less is he under the law. But man is freer than all the animals, on account of his free-will, with which he is endowed above all other animals. Since therefore other animals are not subject to a natural law, neither is man subject to a natural law.

  On the contrary, A gloss on Romans 2:14: "When the Gentiles, who have not the law, do by nature those things that are of the law," comments as follows: "Although they have no written law, yet they have the natural law, whereby each one knows, and is conscious of, what is good and what is evil."

  I answer that, As stated above (Question [90], Article [1], ad 1), law, being a rule and measure, can be in a person in two ways: in one way, as in him that rules and measures; in another way, as in that which is ruled and measured, since a thing is ruled and measured, in so far as it partakes of the rule or measure. Wherefore, since all things subject to Divine providence are ruled and measured by the eternal law, as was stated above (Article [1]); it is evident that all things partake somewhat of the eternal law, in so far as, namely, from its being imprinted on them, they derive their respective inclinations to their proper acts and ends. Now among all others, the rational creature is subject to Divine providence in the most excellent way, in so far as it partakes of a share of providence, by being provident both for itself and for others. Wherefore it has a share of the Eternal Reason, whereby it has a natural inclination to its proper act and end: and this participation of the eternal law in the rational creature is called the natural law. Hence the Psalmist after saying (Ps. 4:6): "Offer up the sacrifice of justice," as though someone asked what the works of justice are, adds: "Many say, Who showeth us good things?" in answer to which question he says: "The light of Thy countenance, O Lord, is signed upon us": thus implying that the light of natural reason, whereby we discern what is good and what is evil, 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 of the eternal law.

  Reply to Objection 1: This argument would hold, if the natural law were something different from the eternal law: whereas it is nothing but a participation thereof, as stated above.

  Reply to Objection 2: Every act of reason and will in us is based on that which is according to nature, as stated above (Question [10], Article [1]): for every act of reasoning is based on principles that are known naturally, and every act of appetite in respect of the means is derived from the natural appetite in respect of the last end. Accordingly the first direction of our acts to their end must needs be in virtue of the natural law.

  Reply to Objection 3: Even irrational animals partake in their own way of the Eternal Reason, just as the rational creature does. But because the rational creature partakes thereof in an intellectual and rational manner, therefore the participation of the eternal law in the rational creature is properly called a law, since a law is something pertaining to reason, as stated above (Question [90], Article [1]). Irrational creatures, however, do not partake thereof in a rational manner, wherefore there is no participation of the eternal law in them, except by way of similitude.

Article 3. Whether there is a human law?

  Objection 1: It would seem that there is not a human law. For the natural law is a participation of the eternal law, as stated above (Article [2]). Now through the eternal law "all things are most orderly," as Augustine states (De Lib. Arb. i, 6). Therefore the natural law suffices for the ordering of all human affairs. Consequently there is no need for a human law.

  Objection 2: Further, a law bears the character of a measure, as stated above (Question [90], Article [1]). But human reason is not a measure of things, but vice versa, as stated in Metaph[ysics]. x, text. 5. Therefore no law can emanate from human reason.

  Objection 3: Further, a measure should be most certain, as stated in Metaph. x, text. 3. But the dictates of human reason in matters of conduct are uncertain, according to Wis. 9:14: "The thoughts of mortal men are fearful, and our counsels uncertain." Therefore no law can emanate from human reason.

  On the contrary, Augustine (De Lib. Arb. i, 6) distinguishes two kinds of law, the one eternal, the other temporal, which he calls human.

  I answer that, As stated above (Question [90], Article [1], ad 2), a law is a dictate of the practical reason. Now it is to be observed that the same procedure takes place in the practical and in the speculative reason: for each proceeds from principles to conclusions, as stated above (De Lib. Arb. i, 6). Accordingly we conclude that just as, in the speculative reason, from naturally known indemonstrable principles, we draw the conclusions of the various sciences, the knowledge of which is not imparted to us by nature, but acquired by the efforts of reason, so too it is from the precepts of the natural law, as from general and indemonstrable principles, that the human reason needs to proceed to the more particular determination of certain matters. These particular determinations, devised by human reason, are called human laws, provided the other essential conditions of law be observed, as stated above (Question [90], Articles [2],3,4). Wherefore Tully [Cicero] says in his Rhetoric (De Invent. Rhet. ii) that "justice has its source in nature; thence certain things came into custom by reason of their utility; afterwards these things which emanated from nature and were approved by custom, were sanctioned by fear and reverence for the law."

  Reply to Objection 1: The human reason cannot have a full participation of the dictate of the Divine Reason, but according to its own mode, and imperfectly. Consequently, as on the part of the speculative reason, by a natural participation of Divine Wisdom, there is in us the knowledge of certain general principles, but not proper knowledge of each single truth, such as that contained in the Divine Wisdom; so too, on the part of the practical reason, man has a natural participation of the eternal law, according to certain general principles, but not as regards the particular determinations of individual cases, which are, however, contained in the eternal law. Hence the need for human reason to proceed further to sanction them by law.

  Reply to Objection 2: Human reason is not, of itself, the rule of things: but the principles impressed on it by nature, are general rules and measures of all things relating to human conduct, whereof the natural reason is the rule and measure, although it is not the measure of things that are from nature.

  Reply to Objection 3: The practical reason is concerned with practical matters, which are singular and contingent: but not with necessary things, with which the speculative reason is concerned. Wherefore human laws cannot have that inerrancy that belongs to the demonstrated conclusions of sciences. Nor is it necessary for every measure to be altogether unerring and certain, but according as it is possible in its own particular genus.

Article 4. Whether there was any need for a Divine law?

  Objection 1: It would seem that there was no need for a Divine law. Because, as stated above (Article [2]), the natural law is a participation in us of the eternal law. But the eternal law is a Divine law, as stated above (Article [1]). Therefore there was no need for a Divine law in addition to the natural law, and human laws derived therefrom.

  Objection 2: Further, it is written (Ecclus. 15:14) that "God left man in the hand of his own counsel." Now counsel is an act of reason, as stated above (Question [14], Article [1]). Therefore man was left to the direction of his reason. But a dictate of human reason is a human law as stated above (Article [3]). Therefore there is no need for man to be governed also by a Divine law.

  Objection 3: Further, human nature is more self-sufficing than irrational creatures. But irrational creatures have no Divine law besides the natural inclination impressed on them. Much less, therefore, should the rational creature have a Divine law in addition to the natural law.

  On the contrary, David prayed God to set His law before him, saying (Ps. 118:33): "Set before me for a law the way of Thy justifications, O Lord."

  I answer that, Besides the natural and the human law it was necessary for the directing of human conduct to have a Divine law. And this for four reasons. First, because it is by law that man is directed how to perform his proper acts in view of his last end. And indeed if man were ordained to no other end than that which is proportionate to his natural faculty, there would be no need for man to have any further direction of the part of his reason, besides the natural law and human law which is derived from it. But since man is ordained to an end of eternal happiness which is inproportionate to man's natural faculty, as stated above (Question [5], Article [5]), therefore it was necessary that, besides the natural and the human law, man should be directed to his end by a law given by God.

   Secondly, because, on account of the uncertainty of human judgment, especially on contingent and particular matters, different people form different judgments on human acts; whence also different and contrary laws result. In order, therefore, that man may know without any doubt what he ought to do and what he ought to avoid, it was necessary for man to be directed in his proper acts by a law given by God, for it is certain that such a law cannot err.

   Thirdly, because man can make laws in those matters of which he is competent to judge. But man is not competent to judge of interior movements, that are hidden, but only of exterior acts which appear: and yet for the perfection of virtue it is necessary for man to conduct himself aright in both kinds of acts. Consequently human law could not sufficiently curb and direct interior acts; and it was necessary for this purpose that a Divine law should supervene.

   Fourthly, because, as Augustine says (De Lib. Arb. i, 5,6), human law cannot punish or forbid all evil deeds: since while aiming at doing away with all evils, it would do away with many good things, and would hinder the advance of the common good, which is necessary for human intercourse. In order, therefore, that no evil might remain unforbidden and unpunished, it was necessary for the Divine law to supervene, whereby all sins are forbidden.

   And these four causes are touched upon in Ps. 118:8, where it is said: "The law of the Lord is unspotted," i.e. allowing no foulness of sin; "converting souls," because it directs not only exterior, but also interior acts; "the testimony of the Lord is faithful," because of the certainty of what is true and right; "giving wisdom to little ones," by directing man to an end supernatural and Divine.

  Reply to Objection 1: By the natural law the eternal law is participated proportionately to the capacity of human nature. But to his supernatural end man needs to be directed in a yet higher way. Hence the additional law given by God, whereby man shares more perfectly in the eternal law.

  Reply to Objection 2: Counsel is a kind of inquiry: hence it must proceed from some principles. Nor is it enough for it to proceed from principles imparted by nature, which are the precepts of the natural law, for the reasons given above: but there is need for certain additional principles, namely, the precepts of the Divine law.

  Reply to Objection 3: Irrational creatures are not ordained to an end higher than that which is proportionate to their natural powers: consequently the comparison fails.


   We must now consider human law; and (1) this law considered in itself; (2) its power; (3) its mutability. Under the first head there are four points of inquiry:

    (1) Its utility.

    (2) Its origin.

    (3) Its quality.

    (4) Its division.

Article 1. Whether it was useful for laws to be framed by men?

  Objection 1: It would seem that it was not useful for laws to be framed by men. Because the purpose of every law is that man be made good thereby, as stated above (Question [92], Article [1]). But men are more to be induced to be good willingly by means of admonitions, than against their will, by means of laws. Therefore there was no need to frame laws.

  Objection 2: Further, As the Philosopher [Aristotle] says (Ethic. v, 4), "men have recourse to a judge as to animate justice." But animate justice is better than inanimate justice, which contained in laws. Therefore it would have been better for the execution of justice to be entrusted to the decision of judges, than to frame laws in addition.

  Objection 3: Further, every law is framed for the direction of human actions, as is evident from what has been stated above (Question [90], Articles [1],2). But since human actions are about singulars, which are infinite in number, matter pertaining to the direction of human actions cannot be taken into sufficient consideration except by a wise man, who looks into each one of them. Therefore it would have been better for human acts to be directed by the judgment of wise men, than by the framing of laws. Therefore there was no need of human laws.

  On the contrary, Isidore says (Etym. v, 20): "Laws were made that in fear thereof human audacity might be held in check, that innocence might be safeguarded in the midst of wickedness, and that the dread of punishment might prevent the wicked from doing harm." But these things are most necessary to mankind. Therefore it was necessary that human laws should be made.

  I answer that, As stated above (Question [63], Article [1]; Question [94], Article [3]), man has a natural aptitude for virtue; but the perfection of virtue must be acquired by man by means of some kind of training. Thus we observe that man is helped by industry in his necessities, for instance, in food and clothing. Certain beginnings of these he has from nature, viz. his reason and his hands; but he has not the full complement, as other animals have, to whom nature has given sufficiency of clothing and food. Now it is difficult to see how man could suffice for himself in the matter of this training: since the perfection of virtue consists chiefly in withdrawing man from undue pleasures, to which above all man is inclined, and especially the young, who are more capable of being trained. Consequently a man needs to receive this training from another, whereby to arrive at the perfection of virtue. And as to those young people who are inclined to acts of virtue, by their good natural disposition, or by custom, or rather by the gift of God, paternal training suffices, which is by admonitions. But since some are found to be depraved, and prone to vice, and not easily amenable to words, it was necessary for such to be restrained from evil by force and fear, in order that, at least, they might desist from evil-doing, and leave others in peace, and that they themselves, by being habituated in this way, might be brought to do willingly what hitherto they did from fear, and thus become virtuous. Now this kind of training, which compels through fear of punishment, is the discipline of laws. Therefore in order that man might have peace and virtue, it was necessary for laws to be framed: for, as the Philosopher says (Polit. i, 2), "as man is the most noble of animals if he be perfect in virtue, so is he the lowest of all, if he be severed from law and righteousness"; because man can use his reason to devise means of satisfying his lusts and evil passions, which other animals are unable to do.

  Reply to Objection 1: Men who are well disposed are led willingly to virtue by being admonished better than by coercion: but men who are evilly disposed are not led to virtue unless they are compelled.

  Reply to Objection 2: As the Philosopher says (Rhet. i, 1), "it is better that all things be regulated by law, than left to be decided by judges": and this for three reasons. First, because it is easier to find a few wise men competent to frame right laws, than to find the many who would be necessary to judge aright of each single case. Secondly, because those who make laws consider long beforehand what laws to make; whereas judgment on each single case has to be pronounced as soon as it arises: and it is easier for man to see what is right, by taking many instances into consideration, than by considering one solitary fact. Thirdly, because lawgivers judge in the abstract and of future events; whereas those who sit in judgment of things present, towards which they are affected by love, hatred, or some kind of cupidity; wherefore their judgment is perverted.

   Since then the animated justice of the judge is not found in every man, and since it can be deflected, therefore it was necessary, whenever possible, for the law to determine how to judge, and for very few matters to be left to the decision of men.

  Reply to Objection 3: Certain individual facts which cannot be covered by the law "have necessarily to be committed to judges," as the Philosopher says in the same passage: for instance, "concerning something that has happened or not happened," and the like.

Article 2. Whether every human law is derived from the natural law?

  Objection 1: It would seem that not every human law is derived from the natural law. For the Philosopher says (Ethic. v, 7) that "the legal just is that which originally was a matter of indifference." But those things which arise from the natural law are not matters of indifference. Therefore the enactments of human laws are not derived from the natural law.

  Objection 2: Further, positive law is contrasted with natural law, as stated by Isidore (Etym. v, 4) and the Philosopher (Ethic. v, 7). But those things which flow as conclusions from the general principles of the natural law belong to the natural law, as stated above (Question [94], Article [4]). Therefore that which is established by human law does not belong to the natural law.

  Objection 3: Further, the law of nature is the same for all; since the Philosopher says (Ethic. v, 7) that "the natural just is that which is equally valid everywhere." If therefore human laws were derived from the natural law, it would follow that they too are the same for all: which is clearly false.

  Objection 4: Further, it is possible to give a reason for things which are derived from the natural law. But "it is not possible to give the reason for all the legal enactments of the lawgivers," as the jurist [Ulpian] says [*Pandect. Justin. lib. i, ff, tit. iii, v; De Leg. et Senat.]. Therefore not all human laws are derived from the natural law.

  On the contrary, Tully [Cicero] says (Rhet. ii): "Things which emanated from nature and were approved by custom, were sanctioned by fear and reverence for the laws."

  I answer that, As Augustine says (De Lib. Arb. i, 5) "that which is not just seems to be no law at all": wherefore the force of a law depends on the extent of its justice. Now in human affairs a thing is said to be just, from being right, according to the rule of reason. But the first rule of reason is the law of nature, as is clear from what has been stated above (Question [91], Article [2], ad 2). Consequently every human law has just so much of the nature of law, as it is derived from the law of nature. But if in any point it deflects from the law of nature, it is no longer a law but a perversion of law.

   But it must be noted that something may be derived from the natural law in two ways: first, as a conclusion from premises, secondly, by way of determination of certain generalities. The first way is like to that by which, in sciences, demonstrated conclusions are drawn from the principles: while the second mode is likened to that whereby, in the arts, general forms are particularized as to details: thus the craftsman needs to determine the general form of a house to some particular shape. Some things are therefore derived from the general principles of the natural law, by way of conclusions; e.g. that "one must not kill" may be derived as a conclusion from the principle that "one should do harm to no man": while some are derived therefrom by way of determination; e.g. the law of nature has it that the evil-doer should be punished; but that he be punished in this or that way, is a determination of the law of nature.

   Accordingly both modes of derivation are found in the human law. But those things which are derived in the first way, are contained in human law not as emanating therefrom exclusively, but have some force from the natural law also. But those things which are derived in the second way, have no other force than that of human law.

  Reply to Objection 1: The Philosopher is speaking of those enactments which are by way of determination or specification of the precepts of the natural law.

  Reply to Objection 2: This argument avails for those things that are derived from the natural law, by way of conclusions.

  Reply to Objection 3: The general principles of the natural law cannot be applied to all men in the same way on account of the great variety of human affairs: and hence arises the diversity of positive laws among various people.

  Reply to Objection 4: These words of the Jurist are to be understood as referring to decisions of rulers in determining particular points of the natural law: on which determinations the judgment of expert and prudent men is based as on its principles; in so far, to wit, as they see at once what is the best thing to decide.

   Hence the Philosopher says (Ethic. vi, 11) that in such matters, "we ought to pay as much attention to the undemonstrated sayings and opinions of persons who surpass us in experience, age and prudence, as to their demonstrations."