Summa Theologica

We must now consider the vices opposed to knowledge and understanding. Since, however, we have treated of ignorance which is opposed to knowledge, when we were discussing the causes of sins (FS, Q[76]), we must now inquire about blindness of mind and dulness of sense, which are opposed to the gift of understanding; and under this head there are three points of inquiry:

(1) Whether blindness of mind is a sin?

(2) Whether dulness of sense is a sin distinct from blindness of mind?

(3) Whether these vices arise from sins of the flesh?

Objection 1: It would seem that blindness of mind is not a sin. Because, seemingly, that which excuses from sin is not itself a sin. Now blindness of mind excuses from sin; for it is written (Jn. 9:41): "If you were blind, you should not have sin." Therefore blindness of mind is not a sin.

Objection 2: Further, punishment differs from guilt. But blindness of mind is a punishment as appears from Is. 6:10, "Blind the heart of this people," for, since it is an evil, it could not be from God, were it not a punishment. Therefore blindness of mind is not a sin.

Objection 3: Further, every sin is voluntary, according to Augustine (De Vera Relig. xiv). Now blindness of mind is not voluntary, since, as Augustine says (Confess. x), "all love to know the resplendent truth," and as we read in Eccles. 11:7, "the light is sweet and it is delightful for the eyes to see the sun." Therefore blindness of mind is not a sin.

On the contrary, Gregory (Moral. xxxi, 45) reckons blindness of mind among the vices arising from lust.

I answer that, Just as bodily blindness is the privation of the principle of bodily sight, so blindness of mind is the privation of the principle of mental or intellectual sight. Now this has a threefold principle. One is the light of natural reason, which light, since it pertains to the species of the rational soul, is never forfeit from the soul, and yet, at times, it is prevented from exercising its proper act, through being hindered by the lower powers which the human intellect needs in order to understand, for instance in the case of imbeciles and madmen, as stated in the FP, Q[84], AA,8.

Another principle of intellectual sight is a certain habitual light superadded to the natural light of reason, which light is sometimes forfeit from the soul. This privation is blindness, and is a punishment, in so far as the privation of the light of grace is a punishment. Hence it is written concerning some (Wis. 2:21): "Their own malice blinded them."

A third principle of intellectual sight is an intelligible principle, through which a man understands other things; to which principle a man may attend or not attend. That he does not attend thereto happens in two ways. Sometimes it is due to the fact that a man's will is deliberately turned away from the consideration of that principle, according to Ps. 35:4, "He would not understand, that he might do well": whereas sometimes it is due to the mind being more busy about things which it loves more, so as to be hindered thereby from considering this principle, according to Ps. 57:9, "Fire," i.e. of concupiscence, "hath fallen on them and they shall not see the sun." In either of these ways blindness of mind is a sin.

Reply to Objection 1: The blindness that excuses from sin is that which arises from the natural defect of one who cannot see.

Reply to Objection 2: This argument considers the second kind of blindness which is a punishment.

Reply to Objection 3: To understand the truth is, in itself, beloved by all; and yet, accidentally it may be hateful to someone, in so far as a man is hindered thereby from having what he loves yet more.

Objection 1: It seems that dulness of sense is not a distinct sin from blindness of mind. Because one thing has one contrary. Now dulness is opposed to the gift of understanding, according to Gregory (Moral. ii, 49); and so is blindness of mind, since understanding denotes a principle of sight. Therefore dulness of sense is the same as blindness of mind.

Objection 2: Further, Gregory (Moral. xxxi, 45) in speaking of dulness describes it as "dullness of sense in respect of understanding." Now dulness of sense in respect of understanding seems to be the same as a defect in understanding, which pertains to blindness of mind. Therefore dulness of sense is the same as blindness of mind.

Objection 3: Further, if they differ at all, it seems to be chiefly in the fact that blindness of mind is voluntary, as stated above(A[1]), while dulness of sense is a natural defect. But a natural defect is not a sin: so that, accordingly, dulness of sense would not be a sin, which is contrary to what Gregory says (Moral. xxxi, 45), where he reckons it among the sins arising from gluttony.

On the contrary, Different causes produce different effects. Now Gregory says (Moral. xxxi, 45) that dulness of sense arises from gluttony, and that blindness of mind arises from lust. Now these others are different vices. Therefore those are different vices also.

I answer that, Dull is opposed to sharp: and a thing is said to be sharp because it can pierce; so that a thing is called dull through being obtuse and unable to pierce. Now a bodily sense, by a kind of metaphor, is said to pierce the medium, in so far as it perceives its object from a distance or is able by penetration as it were to perceive the smallest details or the inmost parts of a thing. Hence in corporeal things the senses are said to be acute when they can perceive a sensible object from afar, by sight, hearing, or scent, while on the other hand they are said to be dull, through being unable to perceive, except sensible objects that are near at hand, or of great power.

Now, by way of similitude to bodily sense, we speak of sense in connection with the intellect; and this latter sense is in respect of certain primals and extremes, as stated in Ethic. vi, even as the senses are cognizant of sensible objects as of certain principles of knowledge. Now this sense which is connected with understanding, does not perceive its object through a medium of corporeal distance, but through certain other media, as, for instance, when it perceives a thing's essence through a property thereof, and the cause through its effect. Consequently a man is said to have an acute sense in connection with his understanding, if, as soon as he apprehends a property or effect of a thing, he understands the nature or the thing itself, and if he can succeed in perceiving its slightest details: whereas a man is said to have a dull sense in connection with his understanding, if he cannot arrive at knowing the truth about a thing, without many explanations; in which case, moreover, he is unable to obtain a perfect perception of everything pertaining to the nature of that thing.

Accordingly dulness of sense in connection with understanding denotes a certain weakness of the mind as to the consideration of spiritual goods; while blindness of mind implies the complete privation of the knowledge of such things. Both are opposed to the gift of understanding, whereby a man knows spiritual goods by apprehending them, and has a subtle penetration of their inmost nature. This dulness has the character of sin, just as blindness of mind has, that is, in so far as it is voluntary, as evidenced in one who, owing to his affection for carnal things, dislikes or neglects the careful consideration of spiritual things.

This suffices for the Replies to the Objections.

Objection 1: It would seem that blindness of mind and dulness of sense do not arise from sins of the flesh. For Augustine (Retract. i, 4) retracts what he had said in his Soliloquies i, 1, "God Who didst wish none but the clean to know the truth," and says that one might reply that "many, even those who are unclean, know many truths." Now men become unclean chiefly by sins of the flesh. Therefore blindness of mind and dulness of sense are not caused by sins of the flesh.

Objection 2: Further, blindness of mind and dulness of sense are defects in connection with the intellective part of the soul: whereas carnal sins pertain to the corruption of the flesh. But the flesh does not act on the soul, but rather the reverse. Therefore the sins of the flesh do not cause blindness of mind and dulness of sense.

Objection 3: Further, all things are more passive to what is near them than to what is remote. Now spiritual vices are nearer the mind than carnal vices are. Therefore blindness of mind and dulness of sense are caused by spiritual rather than by carnal vices.

On the contrary, Gregory says (Moral. xxxi, 45) that dulness of sense arises from gluttony and blindness of mind from lust.

I answer that, The perfect intellectual operation in man consists in an abstraction from sensible phantasms, wherefore the more a man's intellect is freed from those phantasms, the more thoroughly will it be able to consider things intelligible, and to set in order all things sensible. Thus Anaxagoras stated that the intellect requires to be "detached" in order to command, and that the agent must have power over matter, in order to be able to move it. Now it is evident that pleasure fixes a man's attention on that which he takes pleasure in: wherefore the Philosopher says (Ethic. x, 4,5) that we all do best that which we take pleasure in doing, while as to other things, we do them either not at all, or in a faint-hearted fashion.

Now carnal vices, namely gluttony and lust, are concerned with pleasures of touch in matters of food and sex; and these are the most impetuous of all pleasures of the body. For this reason these vices cause man's attention to be very firmly fixed on corporeal things, so that in consequence man's operation in regard to intelligible things is weakened, more, however, by lust than by gluttony, forasmuch as sexual pleasures are more vehement than those of the table. Wherefore lust gives rise to blindness of mind, which excludes almost entirely the knowledge of spiritual things, while dulness of sense arises from gluttony, which makes a man weak in regard to the same intelligible things. On the other hand, the contrary virtues, viz. abstinence and chastity, dispose man very much to the perfection of intellectual operation. Hence it is written (Dan. 1:17) that "to these children" on account of their abstinence and continency, "God gave knowledge and understanding in every book, and wisdom."

Reply to Objection 1: Although some who are the slaves of carnal vices are at times capable of subtle considerations about intelligible things, on account of the perfection of their natural genius, or of some habit superadded thereto, nevertheless, on account of the pleasures of the body, it must needs happen that their attention is frequently withdrawn from this subtle contemplation: wherefore the unclean can know some truths, but their uncleanness is a clog on their knowledge.

Reply to Objection 2: The flesh acts on the intellective faculties, not by altering them, but by impeding their operation in the aforesaid manner.

Reply to Objection 3: It is owing to the fact that the carnal vices are further removed from the mind, that they distract the mind's attention to more remote things, so that they hinder the mind's contemplation all the more.

We must now consider the precepts pertaining to the aforesaid, and under this head there are two points of inquiry:

(1) The precepts concerning faith;

(2) The precepts concerning the gifts of knowledge and understanding.

Objection 1: It would seem that, in the Old Law, there should have been given precepts of faith. Because a precept is about something due and necessary. Now it is most necessary for man that he should believe, according to Heb. 11:6, "Without faith it is impossible to please God." Therefore there was very great need for precepts of faith to be given.

Objection 2: Further, the New Testament is contained in the Old, as the reality in the figure, as stated above (FS, Q[107], A[3]). Now the New Testament contains explicit precepts of faith, for instance Jn. 14:1: "You believe in God; believe also in Me." Therefore it seems that some precepts of faith ought to have been given in the Old Law also.

Objection 3: Further, to prescribe the act of a virtue comes to the same as to forbid the opposite vices. Now the Old Law contained many precepts forbidding unbelief: thus (Ex. 20:3): "Thou shalt not have strange gods before Me," and (Dt. 13:1-3) they were forbidden to hear the words of the prophet or dreamer who might wish to turn them away from their faith in God. Therefore precepts of faith should have been given in the Old Law also.

Objection 4: Further, confession is an act of faith, as stated above (Q[3], A[1]). Now the Old Law contained precepts about the confession and the promulgation of faith: for they were commanded (Ex. 12:27) that, when their children should ask them, they should tell them the meaning of the paschal observance, and (Dt. 13:9) they were commanded to slay anyone who disseminated doctrine contrary to faith. Therefore the Old Law should have contained precepts of faith.

Objection 5: Further, all the books of the Old Testament are contained in the Old Law; wherefore Our Lord said (Jn. 15:25) that it was written in the Law: "They have hated Me without cause," although this is found written in Ps. 34 and 68. Now it is written (Ecclus. 2:8): "Ye that fear the Lord, believe Him." Therefore the Old Law should have contained precepts of faith.

On the contrary, The Apostle (Rom. 3:27) calls the Old Law the "law of works" which he contrasts with the "law of faith." Therefore the Old Law ought not to have contained precepts of faith.

I answer that, A master does not impose laws on others than his subjects; wherefore the precepts of a law presuppose that everyone who receives the law is subject to the giver of the law. Now the primary subjection of man to God is by faith, according to Heb. 11:6: "He that cometh to God, must believe that He is." Hence faith is presupposed to the precepts of the Law: for which reason (Ex. 20:2) that which is of faith, is set down before the legal precepts, in the words, "I am the Lord thy God, Who brought thee out of the land of Egypt," and, likewise (Dt. 6:4), the words, "Hear, O Israel, the Lord thy [Vulg.: 'our'] God is one," precede the recording of the precepts.

Since, however, faith contains many things subordinate to the faith whereby we believe that God is, which is the first and chief of all articles of faith, as stated above (Q[1], AA,7), it follows that, if we presuppose faith in God, whereby man's mind is subjected to Him, it is possible for precepts to be given about other articles of faith. Thus Augustine expounding the words: "This is My commandment" (Jn. 15:12) says (Tract. lxxxiii in Joan.) that we have received many precepts of faith. In the Old Law, however, the secret things of faith were not to be set before the people, wherefore, presupposing their faith in one God, no other precepts of faith were given in the Old Law.

Reply to Objection 1: Faith is necessary as being the principle of spiritual life, wherefore it is presupposed before the receiving of the Law.

Reply to Objection 2: Even then Our Lord both presupposed something of faith, namely belief in one God, when He said: "You believe in God," and commanded something, namely, belief in the Incarnation whereby one Person is God and man. This explanation of faith belongs to the faith of the New Testament, wherefore He added: "Believe also in Me."

Reply to Objection 3: The prohibitive precepts regard sins, which corrupt virtue. Now virtue is corrupted by any particular defect, as stated above (FS, Q[18], A[4], ad 3; FS, Q[19], A[6], ad 1, A[7], ad 3). Therefore faith in one God being presupposed, prohibitive precepts had to be given in the Old Law, so that men might be warned off those particular defects whereby their faith might be corrupted.

Reply to Objection 4: Confession of faith and the teaching thereof also presuppose man's submission to God by faith: so that the Old Law could contain precepts relating to the confession and teaching of faith, rather than to faith itself.

Reply to Objection 5: In this passage again that faith is presupposed whereby we believe that God is; hence it begins, "Ye that fear the Lord," which is not possible without faith. The words which follow—"believe Him"—must be referred to certain special articles of faith, chiefly to those things which God promises to them that obey Him, wherefore the passage concludes—"and your reward shall not be made void."

Objection 1: It would seem that the precepts referring to knowledge and understanding were unfittingly set down in the Old Law. For knowledge and understanding pertain to cognition. Now cognition precedes and directs action. Therefore the precepts referring to knowledge and understanding should precede the precepts of the Law referring to action. Since, then, the first precepts of the Law are those of the decalogue, it seems that precepts of knowledge and understanding should have been given a place among the precepts of the decalogue.

Objection 2: Further, learning precedes teaching, for a man must learn from another before he teaches another. Now the Old Law contains precepts about teaching—both affirmative precepts as, for example, (Dt. 4:9), "Thou shalt teach them to thy sons"—and prohibitive precepts, as, for instance, (Dt. 4:2), "You shall not add to the word that I speak to you, neither shall you take away from it." Therefore it seems that man ought to have been given also some precepts directing him to learn.

Objection 3: Further, knowledge and understanding seem more necessary to a priest than to a king, wherefore it is written (Malachi 2:7): "The lips of the priest shall keep knowledge, and they shall seek the law at his mouth," and (Osee 4:6): "Because thou hast rejected knowledge, I will reject thee, that thou shalt not do the office of priesthood to Me." Now the king is commanded to learn knowledge of the Law (Dt. 17:18,19). Much more therefore should the Law have commanded the priests to learn the Law.

Objection 4: Further, it is not possible while asleep to meditate on things pertaining to knowledge and understanding: moreover it is hindered by extraneous occupations. Therefore it is unfittingly commanded (Dt. 6:7): "Thou shalt meditate upon them sitting in thy house, and walking on thy journey, sleeping and rising." Therefore the precepts relating to knowledge and understanding are unfittingly set down in the Law.

On the contrary, It is written (Dt. 4:6): "That, hearing all these precepts, they may say, Behold a wise and understanding people."

I answer that, Three things may be considered in relation to knowledge and understanding: first, the reception thereof; secondly, the use; and thirdly, their preservation. Now the reception of knowledge or understanding, is by means of teaching and learning, and both are prescribed in the Law. For it is written (Dt. 6:6): "These words which I command thee... shall be in thy heart." This refers to learning, since it is the duty of a disciple to apply his mind to what is said, while the words that follow—"and thou shalt tell them to thy children"—refer to teaching.

The use of knowledge and understanding is the meditation on those things which one knows or understands. In reference to this, the text goes on: "thou shalt meditate upon them sitting in thy house," etc.

Their preservation is effected by the memory, and, as regards this, the text continues—"and thou shalt bind them as a sign on thy hand, and they shall be and shall move between thy eyes. And thou shalt write them in the entry, and on the doors of thy house." Thus the continual remembrance of God's commandments is signified, since it is impossible for us to forget those things which are continually attracting the notice of our senses, whether by touch, as those things we hold in our hands, or by sight, as those things which are ever before our eyes, or to which we are continually returning, for instance, to the house door. Moreover it is clearly stated (Dt. 4:9): "Forget not the words that thy eyes have seen and let them not go out of thy heart all the days of thy life."

We read of these things also being commanded more notably in the New Testament, both in the teaching of the Gospel and in that of the apostles.

Reply to Objection 1: According to Dt. 4:6, "this is your wisdom and understanding in the sight of the nations." By this we are given to understand that the wisdom and understanding of those who believe in God consist in the precepts of the Law. Wherefore the precepts of the Law had to be given first, and afterwards men had to be led to know and understand them, and so it was not fitting that the aforesaid precepts should be placed among the precepts of the decalogue which take the first place.

Reply to Objection 2: There are also in the Law precepts relating to learning, as stated above. Nevertheless teaching was commanded more expressly than learning, because it concerned the learned, who were not under any other authority, but were immediately under the law, and to them the precepts of the Law were given. On the other hand learning concerned the people of lower degree, and these the precepts of the Law have to reach through the learned.

Reply to Objection 3: Knowledge of the Law is so closely bound up with the priestly office that being charged with the office implies being charged to know the Law: hence there was no need for special precepts to be given about the training of the priests. On the other hand, the doctrine of God's law is not so bound up with the kingly office, because a king is placed over his people in temporal matters: hence it is especially commanded that the king should be instructed by the priests about things pertaining to the law of God.

Reply to Objection 4: That precept of the Law does not mean that man should meditate on God's law of sleeping, but during sleep, i.e. that he should meditate on the law of God when he is preparing to sleep, because this leads to his having better phantasms while asleep, in so far as our movements pass from the state of vigil to the state of sleep, as the Philosopher explains (Ethic. i, 13). In like manner we are commanded to meditate on the Law in every action of ours, not that we are bound to be always actually thinking about the Law, but that we should regulate all our actions according to it.