ST. THOMAS AQUINAS: Summa Theologica [Part I-II, QQ 90-97]

Question 90 – Of the Essence of Law (Four Articles)

  • Is law something pertaining to reason?

o   “Law is a rule and measure of acts, whereby man is induced to act or is restrained from acting.” All human acts are ruled and measured by the Reason because it is the first principle in all matters of action. The first principle in any genus is the rule and measure of that genus. For example, the number one is the rule and measure of all numbers, and the first movement is the rule and measure of all movements. Thus, law pertains to reason.

  • Is law always directed to the common good?

o   The ultimate end of human life is happiness. Thus, all action dictated by reason is conducive to happiness. Since man is part of mankind, the law must take universal happiness into consideration. Thus, law is always directed to the common good.

  • Is any man competent to make laws?

o   The right to ordain laws for the common good rests with either the whole community or a representative of the whole community; for “the directing of anything to the end concerns him to whom the end belongs.”

  • Is promulgation essential to law?

o   Promulgation is necessary for law to obtain force because the law is a rule and measure that must be applied to the men who are to be ruled by it.

  • Conclusion: Law “is nothing else than an ordinance of reason for the common good, made by him who has care of the community, and promulgated.”


I appreciate St. Tomas Aquinas’ method. He poses a question, gives three arguments that are contrary to his own position, and then systematically refutes each one of the three objections. This type of structured reasoning helps the readers focus on the most important aspects of a particular question. Some philosophers will digress from the topic of discussion, and therefore confuse and frustrate the readers. I am looking forward to reading the rest of the assigned readings of Aquinas. Although I might not agree with all of his arguments, at the very least, I will be able to understand how he arrived at his conclusions. The same cannot be said for all of Kant’s arguments.


Question 91 – Of the Various Kinds of Law (Six Articles)

  • Is there an eternal law?

o   Yes. Granted that the world is ruled by an eternal god, then god’s reason is an eternal law since his conception of things is not subject to time, but is eternal.

  • Is there a natural law in us?

o   Yes. Law can be something that rules and measures, or something that is measured and ruled, since it is ruled or measured in so far as it partakes in ruling or measuring. Since all things are measured and ruled by Divine reason, all things partake in the eternal law in so far as they derive their inclinations and acts from it. Because rational creatures have a share of Eternal Reason, their share of participation in the eternal Law may be classified as Natural Law. “Natural law is nothing else than the rational creature’s participation of the eternal law.”

  • Is there a human law?

o   Yes, because humans need to decide particular matters. They utilize the natural law, which bestows them with general principles, to create human laws to rule and measure particular matters.

  • Is there any need for Divine law?

o   Yes, for four reasons:

  • Man is directed to an end of eternal happiness, which is beyond his natural faculty. Thus, man requires direction in the form of Divine law.
  • Human judgment is uncertain; different people form different judgments on human acts. Man requires an indubitable law that directs them to do something or refrain from doing something.
  • Man is not able to judge of interior movements of other people’s minds. But it is necessary for a man to conduct himself correctly in both exterior and interior acts in order to attain moral perfection.
  • Human law cannot punish and forbid all evils because many goods would be lost in the endeavor. This would hinder the advancement of the common good. Thus, it is necessary for God to intervene and forbid all sins.
  • Is there only one Divine law?

o   No. Man was in a state of imperfection before the coming of Christ. At that time men required a certain set of laws that were based upon temporal fears and temporal rewards. After the coming of Christ, man now lives in a state of perfection and requires a different set of laws based upon love and eternal happiness. In the Old Testament, men are directed by the Old Law. In the New Testament, men are directed by the New Law. The Old Law directs our exterior acts. The New Law directs both our exterior and interior acts.

  • Is there a law in the inclinations of sensuality?

o   In animals, the inclinations of sensuality have the nature of law, but not in humans; for inclinations of sensuality are deviations from the law of reason, which only man participates in. the law of man is that he act in accordance with reason. The law of animals is to act according to their inclinations.


This entire question is dependent upon a presumption that many people of this age do not make – i.e. the government of this universe by a god. Aquinas states in the very first article of this question: “granted that the world is ruled by Divine providence,” all else follows. If you do not accept this assumption, does that mean that you can disregard the rest of the discussion of this question? No. I think that there are some very instructive intellectual exercises and ideas that Aquinas shares in the other articles. For example, Aquinas claims that attaining eternal happiness is beyond our natural faculties. We require supernatural assistance. This is an idea that is interesting to ponder.


Question 92 – Of the Effects of Law (Two Articles)

  • Is one of the effects of law to make men good?

o   Yes. “Every law aims at being obeyed by those who are subject to it. Thus, the proper effect of law is to lead its subjects to their proper virtue.” Virtue is that which makes something good. Thus, the proper effect of law is to make those subject to it good. If the law is contrary to Divine law, then the law does not make men good in a general sense, but good with regards to that particular government. Thus, a man can be called a good robber, though he is not good in the moral sense of the word.

  • Are the acts of law to command, to forbid, to permit, and to punish?

o   Yes. The law commands all acts of virtue, forbids all acts of vice, permits acts that are neither good nor bad, and exacts punishment in order to induce the subjects to conform to the law through fear. Reward does not properly belong to law because anyone may reward certain behavior; only the lawmaker can punish.


I believe that the most interesting article in this question is the one that considers the acts of law. According to Aquinas, the law does four things: commands, forbids, permits, and punishes. Aquinas’ interpretation of the first three acts of law is fairly standard, but his reasoning with respect to punishment surprised me. He argues that the law induces men behave virtuously through fear of punishment. I agree that many men do obey the law simply because they fear punishment, not because they truly wish to behave virtuously. However, I regard such people differently than I regard people who are genuinely virtuous. When people are motivated by fear, their actions ought to be discredited as a mere animalistic impulse. Such acts do not spring from the will of a person, but are rather a product of circumstance. Aquinas argues that “From becoming accustomed to avoid evil and fulfill what is good, through fear of punishment, one is sometimes led on to do so likewise, with delight and of one’s own accord. Accordingly, law, even by punishing, leads men on to being good.” But until a person reaches the moment when he delights in good deeds, he does not deserve esteem for his actions.


Question 93 – Of the Eternal Law (Six Articles)

  • Is the eternal law a sovereign type existing in God?

o   Yes. “As in every artificer there exists a type of the things that are made by his art, the type in him who governs the acts of his subjects bears the name of law.”  The Divine Wisdom moves all things to their proper end. Thus, the eternal law is the type of Divine Wisdom.

  • Is the eternal law known to all?

o   Yes. A thing can be known in itself or in its effect. A man may know the sun by its rays, despite not being able to see its substance. No one can know the eternal law except the blessed who see God’s essence. But all rational creatures can know the eternal law by its reflection.

  • Is every law derived from the eternal law?

o   Yes. The power of the second mover is always derived from the power of the first mover. The plan of government or crafts flows from the king or chief craftsmen to the inferior administrators and craftsmen. Thus, “all laws, in so far as they partake of right reason, are derived from the eternal law.”

  • Are necessary and eternal things subject to the eternal law?

o   All things created by God are subject to the eternal law. But things pertaining to “the Divine Nature or Essence are not subject to the eternal law.”

  • Are natural contingents subject to the eternal law?

o   Yes. God “imprints on the whole of nature the principles of its proper actions. God commands the whole of nature. All actions and movements of nature are subject to the eternal law. Consequently irrational creatures are subject to the eternal law through being moved by Divine Providence; but not, as rational creatures are, through understanding the Divine commandment.

  • Are all human affairs subject to the eternal law?

o   Yes. Both actions of one’s own volition, and passionate actions are subject to the eternal law, and to the punishments for transgressing the law.


Article 5 of this question is the most interesting – i.e. are natural contingents subject to the eternal law? Aquinas asserts that the actions of irrational beasts and inanimate objects are directed by God. This is consistent with the insurance underwriters’ classifications of hurricanes, tornados, tsunamis, etc. as acts of God. However, there is something very unsettling about this notion given the tremendous suffering that these acts of god produce. Captain Ahab would certainly agree with Aquinas. Ahab considers Moby Dick to be a “pasteboard mask” that is concealing an “inscrutable thing.” That mysterious thing animates the whale; and therefore Ahab seeks to avenge himself on that thing. It is clear that the inscrutable thing is God. Aquinas would agree that the whale is acting according to the will of God, but that Ahab cannot fully comprehend the divine providence which is directing everything to eternal happiness. Ahab would likely scoff at the idea.


Question 94 – Of the Natural Law (Six Articles)

  • Is the natural law a habit?

o   Properly and essentially the natural law is not a habit because it is dictated by reason. But the precepts of the natural law are held in the reason by habit; for sometimes the reason does not contemplate the natural law yet it remains impressed upon one’s mind.

  • Does the natural law contain several precepts, or only one?

o   The natural law contains several precepts, but there are secondary precepts that are derived from primary precepts. A self-evident principle is that all things seek the good. Thus, the primary precept of the natural law is that all things ought to do and pursue good and avoid evil. All other precepts are derived from this one. Natural inclinations include self-preservation and desire to know the truth.

  • Are all acts of virtue prescribed by the natural law?

o   All virtuous acts belong to the natural law; for the rational part of man is the essence of man, and there is a natural inclination to act according to the dictates of reason. Acting according to reason is acting according to virtue.

  • Is the natural law the same in all men?

o   “Although there is necessity in the general principles [e.g. all men are inclined to act according to reason], the more we descend to matters of detail, the more frequently we encounter defects. 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.”

  • Can the law of nature be changed?

o   Things can be added to the law of nature. Many beneficial things for human life have been added by both Divine and human laws. But the fundamental precepts cannot be changed.

o   “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 Kings 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”

  • Can the law of nature be abolished from men’s hearts?

o   The fundamental principles of the natural law can never be blotted out from men’s hearts. “Thy law is written in the hearts of men, which iniquity itself effaces not.”


In this section, Aquinas makes a very provocative assertion. He states that whatever is done and commanded by God is right; “as when God commanded Abraham to slay his innocent son (Gn. 22:2); and when he ordered the Jews to borrow and purloin the vessels of the Egyptians (Ex. 12:35); and when He commanded Osee to take to himself “a wife of fornications” (Osee 1:2).” One can further extrapolate Aquinas’ reasoning to include those acts of god alluded to in my analysis of the previous question. Aquinas justifies all that happens by stating that it is necessary to attain eternal happiness, and that we cannot fully comprehend the divine plan; thus, though it may seem unjust for innocent children to suffer, it is necessary according to God’s will, and we should accept it. Dostoyevsky’s Ivan thoroughly assaults this argument in the Brothers Karamzov in one of the most beautiful passages in literature. It is found in the chapter that precedes the ‘Grand Inquisitor’ and is worth a reading if you are not familiar with it.


I also noticed some similarities between Aquinas and Kant in this chapter. While both men agree that there is a fundamental principle. Aquinas asserts that the fundamental principle becomes more difficult to apply as the particular details and circumstances grow. Whereas Kant obstinately states that his categorical imperative can be applied in all situations, regardless of the circumstances, Aquinas realizes that such an application is not feasible in certain situations. For example, although it is right to return goods to the rightful owner, it is not right to return those goods if the owner intends to harm others with those goods. In this debate, I side with Aquinas.


Question 95 – Of Human Law (Four Articles)

  • Is it useful for laws to be framed by men?

o   Laws check human audacity, safeguard the innocent in the midst of wickedness, and prevent harm by fear of punishment. Though some men are naturally benevolent and virtuous, others are prone to vice. It is necessary to compel the latter people to behave virtuously by means of force and fear. “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.”

o   It is better to have things regulated by law than by judges for three reasons:

  • It is easier to find a few wise men to frame just laws than it is to find the many wise judges necessary to decide aright in every single case.
  • Those who make laws decide what is right with impartiality, being removed from the present circumstances and considering only abstract notions and general acts.
  • Judgments made of present things are susceptible to corrupting influences such as love, hate, or avarice.
  • Is every human law derived from the natural law?

o   Yes. A thing is just if it accords with reason. The first principle of the natural law is to act in accordance with reason. Thus, all human law, in so far as it accords with this principle, is just and is derived from the natural law. If a law contradicts at any point with this fundamental principle, then it is not a law, but a perversion of the law.

  • Is Isidore’s description of the quality of positive law appropriate?

o   Isidore asserts that law is “anything founded on reason, provided that it foster religion, be helpful to discipline, and further the common weal.” This description is appropriate; for law fosters religions in so far as it agrees with the Divine law; it is helpful to discipline in so far as it is proportionate to the natural law; and it furthers the common weal in so far as it is useful to mankind.

  • Is Isidore’s division of human laws appropriate?

o   Isidore appropriately divided laws; for as men differ in their occupations, different rules are necessary to direct their actions. Furthermore, different laws address different actions, and thus laws can appropriately be divided into such classes as assault, rape, murder, theft, etc.


Aquinas reinforces his argument that it is necessary to compel vicious people to behave virtuously by means of force and fear. Clockwork Orange is a wonderful novel written by Anthony Burgess. The novel details a radical conditioning method by which a criminal is forced to behave virtuously. The novel asks a provocative question: is it best that we remove a person’s ability to choose between right and wrong? Aquinas says yes.


Aquinas also believes that if a person is forced to behave virtuously by means of force and fear, then the person will eventually behave virtuously of his own volition. There is a scene in Orwell’s 1984 which is very similar to this notion. In that novel, the narrator is tortured until he truly loves Big Brother. Aquinas would argue that the narrator willingly loves Big Brother at the end of the novel, but it seems clear to me that he was coerced and manipulated to hold this sentiment.


Question 96 – Of the Power of Human Law (Six Articles)

  • Should human law be framed for the community rather than the individual?

o   Yes. The end of law is the common good, not individual good.

  • Does it belong to human law to repress all vices?

o   No. Laws must take into consideration possibility. The same type of life is not possible for the virtuous man and the vicious man. Law is framed for a number of people, the majority of whom are not perfectly virtuous. It is only necessary that the law repress particularly grievous vices. Otherwise, the imperfect people would be unable to bear such rigorous precepts, and consequently fall into greater evils.

  • Does human law prescribe acts of all the virtues?

o   Like the repression of particular vices, the law only prescribes certain virtues for the same reasons of feasibility.

  • Does human law bind a man in conscience?

o   If laws are just, then they are in accordance with the Divine law and bind a man in conscience. If laws are not just, then they are not laws at all, but rather violence, and do not bind a man in conscience.

  • Are all subject to the law?

o   The law is a rule of human acts and a coercive power. Thus, a man is not subject to the laws of a foreign sovereign; a man is not subject to a law if he is subject to a higher law; and a man is not subject to a law if he cannot be coerced to follow the law.

o   Just men are not subject to the law because the will of the just men are in accordance with the law, and thus are not subject to the coercive power of the law. Wicked men are subject to the law because their will is contrary to the law; and thus they are subject to the coercive power of the law.

  • Can a subject of the law act beside the letter of the law?

o   Yes. It is proper that men should constantly evaluate the current laws to ensure that they promote the common good. If the laws no longer promote the common good, then they ought to be altered. Furthermore, a man may act beside the letter of the law in circumstances of necessity; for necessity knows no law. “If, however, the peril be so sudden as not to allow of the delay involved by referring the matter to authority, the mere necessity brings with it a dispensation, since necessity knows no law.”


While I agree with Aquinas’ argument that the law ought to be altered when it is found to be contrary to the advancement of the common good, I think that his statements regarding the impunity bestowed upon those who act under necessity to be a little unsettling. Aquinas believes that people who act under necessity are immune from observing the law; for, in his words, “necessity knows no law.” What I find unsettling about this notion is the difficulty in deciding when one is acting under necessity. As Aquinas states, the majority of men are not perfect in virtue. Locke and Rousseau both conclude that men are not the best judges in their own cases. They can never be impartial. Thus, it seems unlikely that anyone can make an objective determination about whether it is acceptable to transgress the law because of necessity.


Question 97 – Of Change in Laws (Four Articles)

  • Should human law be changed in any way?

o   Human law ought to be changed when reason discovers that a new law would advance the public good more than a previous law. Human law ought to be changed as the condition of men change.

  • Should human law always be changed when something better is presented?

o   Changes ought to be made to the human law only when the benefits of change can compensate for the harm done to the binding force of law whenever a law is changed; for the mere fact of a change in law is prejudicial to the common good.

  • Can custom obtain force of law?

o   Yes. Human reason may be made manifest through words and deeds.

  • Can the rulers of the people dispense from human laws?

o   Yes. When an occasion arises in which the law would fail to achieve its end – the common good – the sovereign may allow the precept of the law not to be observed. He cannot grant this permission for any other reason than the promotion of the common good.


Aquinas’ discussion of custom in this question reminded me of Montaigne’s essay on the same topic. Montaigne detailed the tremendous power of custom, and describes how custom can obtain the ultimate power – i.e. the force of law. Aquinas also asserts a very similar argument made by Montaigne, Locke, and likely many more political thinkers. They believe that changing a law harms the respect a community possesses for the law. Therefore, the law ought only to be changed whenever there would be a greater good that would compensate for the inherent harm.

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