De veritate EN 144



According to Augustine, sin is sometimes in higher reason and sometimes in lower reason. To understand this we must first know two things: which act can be attributed to reason; also, which can be attributed to higher, and which to lower, reason.

Accordingly, we must bear in mind that, just as the apprehensive part is twofold, namely, the lower, which is the sensitive, and the higher, which is the intellective or reasoning part, so the appetitive part, also, is twofold, namely, the lower, which is called sense appetite and is divided into concupiscent and irascible, and the higher, which is called will. These two appetitive parts relate to the corresponding apprehensive parts similarly in some respects and differently in others.

They relate similarly in this, that there can be no movement in either appetite unless some apprehension precedes. For that which is desirable moves the higher or lower appetite only when perceived by under standing or imagination or sense. Because of this, not only appetite, but also understanding, imagination, and sense, are called movers.

They relate differently in this, that there is a natural inclination in the lower appetite, by which it is in a way naturally forced to tend toward that which is desirable. But the higher appetite is not determined to one thing, since the higher appetite is free, whereas the lower is not. For this reason, movement of the lower appetite is not attributed to the apprehensive power, because the cause of that movement does not come from perception, but from an inclination of the appetite. Movement of the higher appetite, however, is attributed to its apprehensive faculty, reason, because the inclination of the higher appetite toward this or that is caused by a judgment of reason. Consequently, we divide the sources of movement into rational, irascible, and concupiscent. In the higher part we use the narnes which belong to perception and in the lower the narnes which belong to appetite.

Therefore, it is clear that an action is attributed to reason in two ways. According to one way, it is attributed to it because it belongs to it directly, inasmuch as it is elicited by reason itself, for instance, the making of a comparison about objects of activity or of knowledge. In the other way, it is attributed to it because it belongs to it mediately through the will, since the will is set in motion through its judgment. Furthermore, just as a movement of appetite which follows a judgment of reason is attributed to reason, so a movement of appetite which follows deliberation of higher reason is attributed to higher reason. This happens when one bases his deliberation about practical matters on the fact that something is acceptable to God, or prescribed by divine law, or acts in some similar way. However, the movement of appetite will belong to lower reason when it follows a judgment of lower reason, as when one decides about practical matters on the basis of lower causes, as, for instance, considering the depravity of the act, the dignity of reason, the enmity of men, or something of this sort.

These two types of consideration are interrelated. For, according to the Philosopher, end has the character of principle in objects of activity. But in speculative sciences the judgment of reason reaches its perfection only when conclusions are analyzed into first principles. Hence, even in objects of activity the judgment of reason is brought to perfection only when there is reference to the last end. For only then will reason give the final decision on activity. And this decision is consent t& the deed. Consequently, consent to the act is attributed to higher reason, which looks to the last end. But pleasure, whether it is complacency or consent in pleasure, is attributed to lower reason by Augustine.

Therefore, when one sins by giving consent to an evil act, the sin is in higher reason, but when one sins through pleasure alone will some deliberation, the sin 5 said to be in lower reason because the disposition of these lower things rests directly will it. Thus, sin is said to exist in higher or lower reason, in so far as the movements of appetite are attributed to reason. But, if we consider the proper act of reason, we say that sin is in the higher or lower reason when higher or lower reason is deceived in its proper act of comparison.

Answers to Difficulties:

According to the Philosopher, just as sense is never deceived in its proper sensible objects, but can be deceived concerning common and accidental sensibles, so understanding is never deceived about its proper object, quiddity, except perhaps accidentally, nor about first principles, which are known as soon as the terms are known, but is deceived in comparing and applying common principles to particular conclusions. Thus it comes about that reason loses its correctness and sin exists in it.

2. Stupidity and ignorance are directly opposed to wisdom and science, as such, but in a certain sense all other sins are indirectly op posed to them, in so far as the rule of wisdom and science, which is required in activity, is perverted through sin. For this reason, every evil man is called one who does not know.

3. Sin is said to be in the will not as in a subject but as in a cause, for the thing must be voluntary to be a sin. But that which is caused by the will is also attributed to reason, for the reason mentioned above.

4. Man’s sin is said to be against reason in so far as it is against right reason, in which there can be no sin.

6. Higher reason is led directly to eternal essences as to its proper objects. But from them it is in some measure diverted to temporal and perishable things, inasmuch as it judges of these temporal things through the eternal essences. Thus, when its judgment about some matter is turned from its proper course, that is ascribed to higher reason.

6. Although higher reason is ordained to this, that t ding to eternal things, it does not always ding to them. Thus, there eau be sin in it.

7. Socrates used a similar reasoning when he wanted to show that one who has certain knowledge does not sin, for, since certain knowledge is more powerful than passion, it is not overcome by it. In answer to this the Philosopher distinguishes certain knowledge into universal and particular, habitual and actual. And he makes a distinction in habitual certain knowledge on this basis, that a habit can be unhindered or repressed, as happens will those who are intoxicated. Accordingly, one who has universal knowledge in act may in a particular case will which a will is concerned have it only in a habit which is repressed through concupiscence or some other passion. As a result, the judgment of reason in the particular case cannot be informed according to the certain universal knowledge, and so it happens that reason errs in its choice. By reason of such an error of choice every evil man is one who does not know, however much certain knowledge in general he may have. In this way, also, reason is led to sin, inasmuch as it is re pressed through concupiscence.


Parallel readings: II Sentences 24, 3, 1, & 4; Quolibet XII, 22, Summa Theol., I-II, 74, 6, & 8; 88, ad 2.


It seems that it is not, for

1. As Augustine says, striking the breast and [saying] the Our Father are the remedies given for venial sins. But consent to pleasure without consent to the deed is numbered among the sins for which striking the breast and [saying] the Our Father are accepted as a remedy. For Augustine says: "Now, when the mind takes pleasure in illicit things in thought alone, not, indeed, seeing them as something to be done, but still holding and gladly desiring these things which should be rejected as soon as they reach the soul, this should be considered to be a sin, but far less a sin than if it decided to carry it out in deed. Therefore, pardon should be sought for such thoughts, too, and we should strike our breasts and say: "Forgive us our trespasses." Therefore, the above-mentioned consent in pleasure is not a. mortal sin.

2. Consent to a venial sin is venial, as consent to a mortal sin is mortal. But pleasure is a venial sin. Therefore, consent to it is venial.

3. In the act of fornication we find two things for which it can be judged evil: the vehemence of the pleasure, which engulfs reason, and the harm coming from the act, namely, the uncertain condition of the children and other things of this sort which would result unless marital relations were regulated by law. But it cannot be said that fornication is a mortal sin by reason of the pleasure, for that intensity of pleasure exists in the marital act [in marriage], which is not a sin. Therefore, it is a mortal sin only because of the harm which comes from the act. So, one who consents to the pleasure of fornication, but not w the act, does not approach fornication under the aspect in which it is a mortal sin. Therefore, he does not seem to sin mortally.

4. Homicide is not less a sin than fornication. But one who thinks about homicide and takes pleasure and consents to the pleasure does not sin mortally. Otherwise, all who enjoyed hearing histories of wars, and consented to this pleasure, would sin mortally. But ibis does not seem probable. Therefore, consent to the pleasure of fornication is not a mortal sin.

5. Since venial and mortal sin are almost an infinite distance apart, which is seen from the distance between the punishment, u venial sin cannot become mortal. But the pleasure which consists in thought alone before consent is venial. Therefore, it cannot become mortal when the consent is added.

6. The essence of mortal sin consists in turning away from God. But to turn away from God belongs not to lower reason, but to higher reason, to which, also, it belongs to turn to God. For opposites belong to the same faculty. Therefore, mortal sin cannot exist in lower reason, and so the consent to pleasure which is ascribed to lower reason by Augustine is not a mortal sin.

7. As Augustine says: "If our desire is moved, it is like a woman being persuaded, but, finally, reason manfully curbs and represses our aroused desire. When this happens, we do not fall into sin. From this, it seems, we perceive that in the spiritual marriage deep within us there is not sin if the woman sins, and the man does not. But when there is consent to pleasure and not to act, the woman sins, and not the man, as Augustine says. Therefore, consent to the pleasure is not a mortal sin.

8. According to the Philosopher, pleasure in good and evil follows the activity by which it is caused. But the exterior act of fornication, which consists in bodily movement, is different from the interior act, namely, the thought. Therefore, pleasure which follows the interior act will be different from that which follows the external act. But the interior act is not of its nature a mortal sin, as the external act is. Therefore, the interior pleasure is not classified as a mortal sin; hence, con sent to such pleasure does not seem to be a mortal sin.

9. Only that seems to be a mortal sin which is forbidden by divine law, as is clear from the definition of sin given by Augustine: "Sin is word or deed or desire against the law of God." But there is no law forbidding consent to pleasure. Therefore, it is not a mortal sin.

10. It seems that we should pass the same judgment on interpretative consent and on express consent. But interpretative consent does not seem to be mortal sin because sin is carried over to another faculty only through an act of that faculty. In interpretative consent, how ever, there is not any act of reason, which is said to consent, but only negligence in repressing illicit movements. Therefore, interpretative consent to pleasure is not a mortal sin, and express consent is, likewise, not a mortal sin.

11. As has been said, an act is a mortal sin because it is against a divine precept. Otherwise, God would not be despised in the transgression of the precept, and thus the mind of the sinner would not be turned away from God. Lower reason, however, does not take the norm of the divine precept into consideration. For this is the task of higher reason, which considers eternal norms. Therefore, there can be no mortal sin in lower reason; hence, consent mentioned above is not a mortal sin.

12. Since there are two elements in sin, turning toward and turning away, the turning away follows the turning toward. For, by the very fact one turns toward one contrary, he turns away from the other. But he who consents to the pleasure and not to the act does not fully turn to changeable good, since completeness is in the act. Therefore, in this there is not complete turning away; hence, no mortal sin.

13. As the Gloss says: "God is more inclined to be merciful than to punish." But, if one took pleasure in meditating on divine commands and consented to such pleasure, he would not merit, as long as he did not propose to fulfil the divine commands in deed. Therefore, neither will one merit punishment if he consents to the pleasure of sin, provided that he does not decide to fulfil it in deed. Accordingly, he does not seem to sin mortally.

14. The lower power of reason is compared to woman. But woman is not mistress of her will, for, as the Apostle says (1Co 7,4): she "does not have power over her body." Therefore, neither is the lower part of reason master of its will; hence, it cannot sin.

To the Contrary:

1'. No one is damned except for mortal sin. But man will be damned for consent to pleasure. Hence, Augustine says: "The whole man will be damned, unless these things which are perceived to be sins only of thought, and which exist without the will to do them, but still will the will to delight the mind will them, are remitted through the grace of the Mediator." Therefore, consent to pleasure is a mortal sin.

2’. Pleasure in an activity and the activity itself are reduced to the same genus of sin, just as the activity of a virtue and pleasure in it are reduced to the same virtue. For it belongs to the just man to perform just deeds and to take pleasure in them, as is clear in the Ethics. But the act of fornication is classified as a mortal sin. Therefore, the pleasure in the thought of fornication is, too. Therefore, consent to the pleasure will be a mortal sin.

3'. If there could not be mortal sin in lower reason, gentiles, who consider only the lower norms of action, would not sin mortally by fornicating or doing something of the sort. This is obviously false. Therefore, there can be mortal sin in lower reason.



The question whether deliberate pleasure in bad thoughts is a mortal sin and the question about consent to pleasure is the same. For there can be no doubt whether deliberate pleasure in bad thoughts is a sin, if it is called such (morosa) from duration (mora) of time. For it is certain that mere length of time cannot give an act the character of mortal sin, unless something else intervenes, since length of time is not a circumstance aggravating to infinity. But what is doubtful seems to be this: whether the pleasure which is called such because of the super added consent of reason is a mortal sin. There have been different opinions about this.

For some have said that it is not a mortal sin, but venial. This opinion seems to be opposed to the words of Augustine, who threatens man will damnation because of such consent, as is clear from the passage cited. Furthermore, the almost universal opinion of moderns contradicts this [first] position, which seems, also, to tend to ward danger for souls, since from consent in such pleasure a man can very readily fall into sin.

Hence, it seems that we must accept the second opinion, which makes such consent a mortal sin. The truth of this position can be seen from the following. For we must bear in mind that, just as sensible pleasure follows on the external act of fornication, so interior pleasure follows on the act of thinking. But a double pleasure follows on thought. One of these follows from the thought and the other from the thing thought of. For at times we take pleasure in thought because of the thought itself, from which we get actual knowledge of certain things, although the things displease us. Thus, a just man thinks about sins when he discusses or argues about them, and takes pleasure in the truth of this thought. But the pleasure follows because of the things thought when the thing thought about itself stirs up and attracts the affections. In some acts, these two thoughts obviously differ and are clearly distinct. But their distinction is more obscure in thoughts about sins of the flesh, because, due to the weakened condition of the concupiscible part, when there is thought of such desirable objects, there immediately follows in the concupiscible part a movement which is caused by these objects.

Therefore, the pleasure which follows thought because of the thought is ascribed to an altogether different genus than the pleasure of the exterior act. Consequently, when any such pleasure follows the thought of evil things, it is either no sin at all, but a praiseworthy pleasure, as when one takes delight in the knowledge of the truth; or, if there is some Jack of moderation, it is classed under the sin of curiosity.

But the pleasure which follows thought because of the thing thought about belongs to the same class as the pleasure of the external act. For, as is said in the Metaphysics, pleasure consists essentially in the act, but the hope and memory are pleasurable because of the act. From this it is clear that such pleasure is inordinate in its genus by reason of the same disorder which makes external pleasure inordinate.

Accordingly, if the external pleasure is conceded to be mortally sinful, then the interior pleasure, considered in itself and independently, belongs to the genus of mortal sin. Moreover, mortal sin results when ever reason gives itself over to mortal sin by approving of it. For the uprightness of justice is banished from reason when it is made subject to evil by approving of it. And reason makes itself subject to this disordered pleasure when it consents to it. This is the first subjection by which it enslaves itself. Sometimes, there follows on this subjection the choice of the disordered act itself, in order to attain this pleasure more perfectly. And, the more it seeks for further disorders to obtain pleasure, the more it advances in sin. Yet the consent by which it accepted the pleasure will be the first root of that whole progression. Thus, mortal sin begins there.

Consequently, we concede without reserve that consent in the pleasure of fornication or of any other mortal sin is a mortal sin. From this it also follows that whatever a man does because of consent to scull pleasure will a view to fostering or holding it, such as shameful touches, or lustful kisses, or things such as these, the whole thing is a mortal sin.

Answers to Difficulties:

1. As Augustine says, [saying] the Our Father and [ding] other works of this sort have value not only to will out venial sins, but also for the remission of mortal sins, although they are not sufficient for the remission of mortal sins as they are for the remission of venial sins.

2. The pleasure that follows the pleasure in fornication because of the thing thought about is of its nature mortal, but it can be venial accidentally, in so far as it precedes deliberate assent which gives mortal sin its complete character. Without this, if the body were defiled by violence, there would not be mortal sin, for, as Lucy says, the body cannot be defiled will the defilement of sin without the consent of the mind. Therefore, when consent comes, the above-mentioned accident is withdrawn and there is mortal sin, as would happen in a woman who, if she gave consent, would be corrupted through violence.

3. The whole disorder of fornication, from whatever source it arises, flows over into the pleasure which it causes. Hence, one who approves pleasure of this sort sins mortally.

4. If one took pleasure in the thought of murder because of the thing thought about, this would be only by reason of an inclination which he had toward murder; hence, he would sin mortally. However, if one took pleasure in such thought because of knowledge of the things about which he is thinking, or for some other reason of this sort, it would not always be a mortal sin. It would, rather, be classed under some other genus of sin than murder, such as curiosity or some thing else of this sort.

5. The pleasure which was venial will never, as numerically the same, become mortal, but the act of consent added to it will be a mortal sin.

6. Although higher reason alone is of itself directed to God, lower reason to some degree shares in this conversion, in so far as it is ruled by higher reason. Similarly, the concupiscent and irascible are said to share in reason to some degree in so far as they obey reason. Thus, the turning away [from God] in mortal sin can belong to lower reason.

7. In Against the Manicheans, Augustine does not explain those three things as he does in The Trinity. In the latter, he attributes serpent to sensuality, woman to lower reason, and man to higher reason; whereas, in the former, he attributes serpent to sense, woman to concupiscence or sensuality, and man to reason. Therefore, it is clear that the conclusion does not follow.

8. The internal act, that is to say, thought, has pleasure of a kind different from the pleasure of the external act. And this follows thought for its own sake. But the pleasure which follows thought because of the act thought about is put in the same class [as the act] because no one takes pleasure in something unless he is attached to it and perceives it as agreeable. Consequently, one who consents to interior pleasure also approves the exterior pleasure and wants to enjoy it, at least by thinking about it.

9. Consent to pleasure is forbidden by the precept: "Thou shall not covet..."(Ex 20,17 Dt 5,2 Dt 5,1). For it is not without cause that different precepts are given in the law for the external act and the internal desire. Nevertheless, even if it were not forbidden in any special commandment, all the consequences of fornication which concern the same object would be forbidden by the very fact that fornication is forbidden.

10. Before reason considers its own pleasure or harm, it does not have interpretative consent, even though it does not resist. But, when it has considered the rising pleasure and the harm that will follow, it seems to consent, as a man seems to consent, unless he openly resists when he perceives that he will be completely drawn to sin by pleasure of this sort, and will fall headlong. Then the sin is attributed to reason because of its act, since to act and not to act when one should are reduced to [one] genus, inasmuch as sin of omission is reduced to sin of act.

11. The force of a commandment of God reaches lower reason inasmuch as it shares the rule of higher reason, as has been said.

12. The conversion by which one turns after deliberation to some thing which is of its nature evil is sufficient for the character of mortal sin, although another complete act can be added to this one.

13. As Dionysius says: "Good is caused by one whole and complete cause, but evil by individual defects." Thus, more things are required for something to be a meritorious good than for it to be a blame worthy evil, although God is more inclined to reward good deeds than to punish evil ones. Consequently, consent to pleasure without consent to the deed is not enough for merit, but, when there is question of evil, it is enough for blame.

14. By right a woman ought not to will anything contrary to the just appointment of her husband, but, as a matter of fact, sometimes one can and does will the opposite. Thus it is will lower reason.

Answers to Contrary Difficulties:

We concede the arguments to the contrary, although the last concludes falsely. For it proceeds as though a gentile could not sin ac cording to higher reason. And this is false, for there is no one who does not judge that something is the end of human life. And, when he uses that as a basis of his deliberation, he is using higher reason.


Parallel readings: II Sentences 24, 3, g; Summa Theol., I-II, 74, 9-10; Q. D. de malo, 7, 5.


It seems that it cannot, for

1. It belongs to higher reason to ding to the eternal norms of con duct. Therefore, sin can be in it only in so far as it turns away from these eternal norms. But to turn away from them is a mortal sin. There fore, there can be only mortal sin in higher reason.

2. Through contempt venial sin becomes mortal. But there seems to be contempt when one considers something to be evil and to be punished by God and, nevertheless, consents to commit it. Therefore, it seems that there is a mortal sin whenever one consents to the act even of a venial sin after the consideration of higher reason.

3. There is something in the soul, sensuality, in which there can be only venial sin, and something in which there can be venial and mortal sin, namely, lower reason. Therefore it seems that there is also some thing in the soul in which there can be only mortal sin. But this is not synderesis, because in that there is no sin. Therefore, this description fits higher reason.

4. In angels and in man in the state of innocence there could not be venial sin, because venial sin arises from the weakening of the flesh, and this did not then exist. But higher reason is apart from the weakening of the flesh. Therefore, there can be no venial sin in it.

To the Contrary:

1'. Consent to the act of sin is not more serious than the act of sin itself. But consent to the act of venial sin belongs to higher reason. Therefore so does venial sin.

2’. An unpremeditated movement of infidelity is a venial sin, and this takes place only in higher reason. Therefore, there is venial sin in it.



There can be venial and mortal sin in the higher part of reason. Nevertheless, there is some subject matter concerning which there can be only mortal sin in higher reason. This is plain in what follows. For higher reason has an act concerning some matter directly, that is, concerning eternal norms, and an act concerning some matter indirectly, that is, temporal norms, about which it judges according to eternal norms. With reference to its proper matter, eternal norms, it has a double act, one unpremeditated and one deliberate. But, since mortal sin is committed only after the act of deliberation, there can be venial sin in higher reason when there is an unpremeditated movement, and mortal when there is deliberate movement, as we see in the sin of infidelity. But it has only a deliberate act will reference to the matter of temporal things because it is directed to them only when it compares the eternal norms will them. Consequently, the act of higher reason will always be a mortal sin in this matter, if such matter is by nature a mortal ski. But, if it is by nature a venial sin, it will be venial, as is clear when one gives consent to an idle word.

Answers to Difficulties:

1. Higher reason sins in this, that it turns away from eternal norms not only by acting against them, but by acting outside them, which is a venial sin.

2. Not every contempt makes a sin mortal, but contempt of God. And through this alone man is turned away from God. But, when one consents to a venial sin after any deliberation, no matter how much, he does not have contempt of God, unless, perhaps, he would judge that the sin is contrary to a divine commandment. Thus, the conclusion does not follow.

3. That there can be only venial sin in sensuality comes from its imperfection. But reason is a perfect power and, therefore, there be sin in it according to every difference of sin. For its act can be complete in any genus. Hence, if it is by nature a venial sin, it is venial; if it is by nature a mortal sin, it is mortal.

4. Although higher reason is not directly connected will the flesh, the weakening of the flesh reaches it, inasmuch as higher powers receive something from the lower powers.

QUESTION 16: Synderesis


Parallel readings: II Sentences 24, 2, Summa Theol., I, 7 12.


It seems to be a power, for

1. Parts resulting from the same division belong to the same genus. But, as Jerome says, synderesis is differentiated from reason, the concupiscent, and the irascible. Therefore, since the irascible, the concupiscent, and reason are powers, synderesis will also be a power.

2. It was said that synderesis does not denote a power alone, but an habituated power.—On the contrary, a subject will an accident is not divided from a subject alone. For a division of animals into man and white man would be improper. Therefore, since a habit is related to a power as an accident to its subject, it does not seem that that which denotes a power alone, as reason, the irascible, and the concupiscent, can be fittingly divided from that which denotes an habituated power.

3. The same power may have different habits. Therefore, if one power is distinguished from another by reason of a habit, the division in which the parts of the soul are distinguished from each other ought to have as many members as there are habits of the powers.

4. One and the same thing cannot be regulator and that which is regulated. But a power is regulated by its habit. Therefore, a power and a habit cannot so blend into one thing that one name will at the same time denote the power and the habit.

5. Nothing is inscribed in a habit, but only in a power. But the general principles of law are said to be inscribed in synderesis. Therefore, it denotes a power without qualification.

6. One thing cannot arise from two things unless one of the two is changed. But the natural habit which the name synderesis is said to represent is not changed, since what is natural must be permanent. Neither are the faculties of the soul changed. Therefore, it seems that one thing cannot result from a habit and a faculty so that both can be given the one name.

7. Synderesis is opposed to sensuality, for, as sensuality always in clines to evil, so synderesis always inclines to good. But sensuality is simply a faculty without a habit. Therefore, synderesis denotes simply a faculty.

8. As is said in the Metaphysics, the nature which the name signifies is the definition. Therefore, that which is not one in such a way that it can be defined, cannot be signified by one name. Rather, it is a combination made up of a subject and an accident. Thus, when I say "white man," it cannot be defined, as is proved in the Metaphysics. The same is true of the combination of a power and a habit. Consequently, a power together will a habit cannot be denoted by one name.

9. Higher reason is the name of a power alone. But synderesis seems to be the same thing as higher reason. For, as Augustine says, in the seat of natural judgment, which we call synderesis, "there are certain rules and lights of the virtues, and things true and things unchangeable." However, it belongs to higher reason, according to Augustine, to grasp unchangeable natures. Therefore, synderesis is simply a power.

10. According to the Philosopher, everything that is in the soul is either a power, a habit, or a passion. Therefore, either the division of the Philosopher is inadequate or there is nothing in the soul which is at once a power and a habit.

11. Opposites cannot exist in the same thing. But we have an innate tendency (fumes) which always inclines to evil. Therefore, there can not be in us a habit which always inclines to good. Thus, synderesis, which always inclines to good, is not a habit, nor an habituated power, but simply a power.

12. A power and a habit suffice for activity. Therefore, if synderesis is a power will an innate habit, since synderesis inclines to good, man will be capable of performing good actions by reason of purely natural gifts. But this seems to be the heresy of Pelagius.

13. If synderesis is an habituated power, it will not be a passive power but an active one, since it will have some activity. Moreover, just as a passive power is rooted in matter, so an active power is rooted in a form. But in the human soul there is a twofold form: one through which it corresponds to the angels, in so far as it is a spirit, and this is the higher form; and another, the lower form, through which it gives life to the body, in so far as it is a soul. Therefore, synderesis must be based on the higher or the lower form. If on the higher, it is higher reason; if on the lower, it is lower reason. But both higher and lower reason designate simply a power. Therefore, synderesis is simply a power.

14. If synderesis denotes an habituated power, the habit must be innate. For, if it were an acquired or an infused habit, it would be possible to lose synderesis. But synderesis does not denote an innate habit. Therefore, it signifies simply a power. We prove the minor in this way. Every habit which presupposes an act [ in time is not an innate habit. But synderesis presupposes an act [ in time, for it belongs to synderesis to speak out against evil and stir on to good. And this could not take place unless good and evil are actually known be forehand. Therefore, synderesis requires an act [ in time.

15. The function of synderesis seems to be to make judgments. Hence it is called the natural seat of judgment. But free choice takes its name from judging. Therefore, free choice is the same as synderesis. But free choice is simply a power. Therefore, so is synderesis.

16. If synderesis is an habituated power, a kind of composite of the two, it will not be such by logical composition, by which a species is composed of genus arid difference, for a power is not related to a habit as genus to difference. For, thus, any habit added to a power would constitute a distinct power. Therefore, it is natural composition. But in natural composition the compound is different from the elements that make it up, as is proved in the Metaphysics. Therefore, synderesis is neither a power nor a habit, but something else. But this cannot be. Therefore, it remains that it is simply a power.

To the Contrary:

1'. If synderesis is a power, it must be a power of reason. But the powers of reason are directed to opposites. Therefore, synderesis will be directed to opposites, which is clearly false, because it always urges to good and never to evil.

2’. If synderesis is a power, it is either the same as reason, or it is different from it. But it is not the same, because it is distinguished from reason in the comment of Jerome, as noted above. And we cannot say that it is different from reason, for a special power requires a special activity. And there is no act ascribed to synderesis which cannot be performed by reason. For reason itself urges to good and speaks out against evil. Therefore, synderesis is in no way a power.

3'. The tendency to evil (fumes) always inclines to evil, and synderesis always to good. Therefore, these two are directly opposed. But the tendency to evil is a habit, or acts like habit, for concupiscence, which, according to Augustine, is habitual in children and actual in adults, is called the tendency to evil. Therefore, synderesis, also, is a habit.

4’. If synderesis is a power, it is cither cognitive or tends to action. But it is clear that it is not simply cognitive from the fact that its act is to incline us to good and warn us against evil. Therefore, if it is a power, it will tend to action. But this is obviously false, for the powers which tend to action are adequately divided into the irascible, the concupiscent, and the rational. And synderesis is distinguished from these, as has been said. Therefore, synderesis is in no way a power.

5’. Just as in the operative part of the soul synderesis never errs, so in the speculative part understanding of principles never errs. But understanding of principles is a habit, as is clear from the Philosopher. Therefore, synderesis is a habit.

De veritate EN 144