De veritate EN 142
142
For a clear understanding of this question we must investigate the difference between reason and understanding. We must bear in mind that, according to Augustine, just as among corporeal substances there is an orderly disposition, according to which some are said to be higher than others and have control over them, so, too, among spiritual substances there is a certain orderly disposition.
The difference between higher and lower bodies seems to lie in this, that the lower bodies reach the perfection of their existence through the movement of generation, change, and increase. This is obvious in stones, plants, and animals. Higher bodies, however, have the perfection of their existence according to their substance, power, quantity, and figure immediately in their very beginning without any move merit. This is obvious in the sun, moon, and stars. The perfection of spiritual nature, however, lies in the cognition of truth. Consequently, there are some higher spiritual substances which immediately in the beginning receive knowledge of truth without any movement or reasoning by a sudden or simple reception. This is the case will angels, and for this reason they are said to have godlike understanding. There are, also, lower spiritual substances, which can arrive at perfect knowledge of truth only through a certain movement, in which they go from one thing to another, in order to reach knowledge of things un known through those which are known. This is proper to human souls. And this is why angels are called intellectual substances, whereas souls are called rational substances.
Understanding seems to indicate simple and absolute knowledge. And one is said to understand (intelligere) because in some sense he reads (legit) the truth within (intus) the very essence of the thing. Reason, on the other hand, denotes a transition from one thing to another by which the human soul reaches or arrives at knowledge of something else. For this reason, Isaac says that reasoning is the progress of the cause to the thing caused.
Now, all movement proceeds from what is at rest, as Augustine says. For rest is the term of motion, as is said in the Physics. Thus, movement is related to rest as to its source and its term, as is reason, also, which is related to understanding as movement to rest and generation to existence, as is clear from the citation from Boethius given above. It is related to understanding as to its source and its term. It is related to it as its source because the human mind could not move from one thing to another unless the movement started from some simple perception of truth, and this perception is understanding of principles. Similarly, the movement of reason would not reach any thing certain unless there were an examination of that which it came upon through discursive movement of the mind. This examination proceeds to first principles, the point to which reason pursues its analysis. As a result, we find that understanding is the source of reasoning in the process of discovery and its term in that of judging.
Consequently, although the knowledge proper to the human soul takes place through the process of reasoning, nevertheless, it participates to some extent in that simple knowledge which exists in higher substances, and because of which they are said to have intellective power. This is in keeping will the rule which Dionysius gives, that divine wisdom "always joins the limits of higher things to the beginnings of the lower things." This is to say that the lower nature at its highest point reaches something of that which is lowest in the higher nature.
Dionysius also points out this difference between angels and souls when he says: "From divine wisdom the intellectual powers of angelic minds have pure and good acts of understanding, not gathering divine knowledge from divisible things or the senses or extended discussions, but uniformly understanding the intelligible things of God." Later, he adds about souls: Therefore, because of the divine wisdom, souls have rationality, too, "but spread out, circling about the truth of existing things, by the diversity of division falling short of unitive minds. But through the reduction of many things to one by reflection souls are held worthy of acts of understanding equal to those of angels, in so far as this is proper and possible to souls." He says this because that which belongs to a higher nature cannot exist in a lower nature perfectly, but only according to a slight participation. Thus, in sensitive nature there is not reason, but only a participation of reason inasmuch as brute animals have a kind of natural prudence, as appears plainly in the Metaphysics.
However, what is thus shared is not held as a possession, that is, as something perfectly within the power of the one who has it. In this sense it is said in the Metaphysics that knowledge of God is a divine and not a human possession. As a result, no power is assigned for that which is held in this manner. Thus, brute animals are not said to have any reason, although they share to some degree in prudence. But this exists in them according to a natural [instinctive] judgment. Similarly, there is no one special power in man through which he gets knowledge of truth simply, absolutely, and without movement from one thing to another. Such perception of truth is in man through a natural habit, which is called understanding of principles. Accordingly, there is no power in man separate from reason which is called understanding. Rather, reason itself is called understanding because it shares in the intellectual simplicity, by reason of which it begins and through which it terminates its proper activity. For this reason, the proper act of understanding is attributed to reason in Spirit and Soul. And that which is proper to reason is given as the act of reason, where it says that reason is the sight of the soul by which it looks at the true through itself; reasoning, however, is the investigation of reason.
Even if we conceded that it were properly and completely fitting for us to have some power for simple perception and independent knowledge of the truth which is in us, it would not be another power than reason. This is clear from what follows, for, according to Avicenna, different acts indicate a difference of powers only when they cannot be referred to the same principle. Thus, in physical things, to receive and to retain are not reduced to the same principle, but the former is referred to the wet and the latter to the dry.
Therefore, imagination, which retains bodily forms in a physical organ, is a different power from sense, which receives these forms through a physical organ. However, the act of reason, which is to move from one thing to another, and the act of understanding, which is to grasp truth directly, are related to each other as generation to existence and movement to rest. But to be at rest and to be moved are reduced to the same principle in all things in which both are found. For a thing is moved to a place through the same nature through which it rests in a place. And that which is at rest and that which is moved are like perfect and imperfect. Hence, the power which moves in thought from one thing to another and the power that perceives truth are not different powers, but one power which knows truth absolutely, in so far as it is perfect, and needs movement in thought from one thing to another, in so far as it is imperfect.
Consequently, in us, reason, taken strictly, can in no way be a power different from understanding. But, sometimes, the cogitative power, which is a power of the sensitive soul, is called reason, since it makes comparisons between individual forms, just as reason, properly so called, does between universal forms, as the Commentator says. This has a definite organ, the middle cell of the brain. And this reason is, without doubt, a power different from understanding. But we are not speaking of this at present.
Answers to Difficulties:
1. Spirit and Soul is not authentic and is not believed to belong to Augustine. Nevertheless, in support of what it says, one can say that in what he said the author did not intend to distinguish powers of the soul, but to show the different steps by which the soul advances in knowledge, so that through the senses it knows forms in matter, through imagination it knows accidental forms without matter, but will the conditions of matter. Through reason it knows the essential form of material things without the individual matter. From this it rises higher in the possession of some kind of knowledge of created spirits, and, thus, is said to have understanding, since spirits of this sort have prior knowledge of substances which exist entirely without matter. From this it goes even further to some knowledge of God himself, and thus is said to have intelligence, which gives the proper name of the act of understanding, since to know God is proper to God, whose understanding is His intelligence, that is, His act of understanding.
2. As Boethius says: "The higher power embraces the lower, but the lower in no way rises to the higher." Hence, a higher nature can do fully what belongs to the lower, but it cannot perform fully what belongs to one still higher. Therefore, the nature of the rational soul has powers for the things that belong to sensitive and vegetative nature, but not for the things that belong to the intellectual nature which exists above it.
3. Since, according to the Philosopher, common sense perceives all sensibles, it must be drawn to them according to one common character; otherwise it would not have one object of its own. None of the proper senses can attain to this common character of object. Reason, on the other hand, reaches direct understanding as its term when, for example, the movement of reason concludes at science. Consequently, it is not necessary that in us understanding be a different power from reason, as common sense differs from the proper senses.
4. To judge is not a property of reason through which it can be distinguished from understanding. For understanding, too, judges that this is true and that false. But judgment and the comprehension of intelligence are referred to reason to this extent, that in us judgment commonly takes place through analysis into principles, whereas direct comprehension of truth takes place through understanding.
5. That which is altogether simple completely lacks composition. But simple things are preserved in composite things. Thus it is that what belongs to the composite, in so far as it is composite, is not found in what is simple. Accordingly, a simple body does not have taste, which follows upon mixture. But compound bodies have the things which belong to simple bodies, although in an inferior manner. Thus, hot and cold, light and heavy, are found in compound bodies. There fore, there is no composition in the divine understanding, which is entirely simple. But our reason, although it is composite, can enter upon simple act and composite act, either as it puts subject and predicate together or joins principles in order to arrive at a conclusion, because there is something of the nature of the simple in it, as the model is in its image.
Therefore, in us, it is the same faculty which knows the simple quiddities of things, which forms propositions, and which reasons. The last of these is proper to reason, as reason; the other two can also be long to understanding, as understanding. Hence, the second is found in angels, since they know through many species, but only the first is in God, who understands alI things, simple and composite, by knowing His own essence.
6. In some sense the soul knows itself through itself, inasmuch as to know is to possess in itself knowledge of itself, and in some sense it knows itself through a species of an intelligible object, in so far as knowing implies thinking and distinguishing of self. Thus, the Philosopher and Augustine are speaking of the same thing. Hence, the conclusion does not follow.
7. Such difference of objects cannot diversify faculties, because it is based on accidental differences. This has been proved above. Bodily nature is thus given as the object of reason, because it is proper to human knowledge to begin from sense and phantasm. For this reason, the gaze of our understanding, which is properly called reason, inasmuch as reason is proper to the human race, first fastens on the natures of sensible things. From this it rises higher in its knowledge of created spirit, which is more within its competence according to its participation of higher nature than according to that which is proper and perfectly fitted to it.
8. Boethius intends intelligence and reason to be different cognoscitive powers, not of the same subject, but of different subjects. Thus, he intends reason to belong to man, and so he says that it knows general forms existing in individual things, since human knowledge properly concerns forms drawn from the senses. Moreover, he intends intelligence to belong to higher substances, which in their first glance apprehend completely immaterial forms. Accordingly, he does not in- tend that reason should ever reach that which belongs to intelligence, since we can never in the weakness of this knowledge attain to sight of the quiddities of immaterial substances. However, we will do this in heaven when we will be made godlike through glory.
9. In so far as reason and understanding are in different beings, they are not the same power. But the present question concerns them in so far as both exist in man.
10. This reasoning proceeds correctly for acts which belong to different powers. But one power may have different acts, one of which is before the other. Thus the act of possible intellect is to understand essence and to form propositions.
11. The soul knows both, but through the same power. Nevertheless, it seems proper to the human soul, as rational, to know being in this thing. But to know being simply seems to belong rather to the higher substances, as is clear from the passage cited above.
12. To love God and to choose virtues are attributed to reason, not because they belong to it directly, but in so far as the will is attracted to God as its end, and to virtues as means to that end by the judgment of reason. It is in this way, too, that rational is distinguished from the irascible and the concupiscible, since we are inclined to action by the judgment of reason or by passion, which is in the irascible or concupiscible parts. The will is also said to be in reason inasmuch as it is in the rational part of the soul, just as memory is said to be in sense since it is in the sensitive part of the soul, and not because it is the same power.
13-14. The solution to the thirteenth and fourteenth difficulties is clear from what has been said.
Parallel readings: II Sentences 24, 2, 2; Summa Theol., I, 79, 9.
Difficulties:
It seems that they are, for
As Augustine says, the image of the Trinity is in the higher part of reason, but not in the lower. But the image of God in the soul is made up of the three powers. Therefore, lower reason does not belong to the same power or powers as higher reason. Thus, they seem to be different powers.
2. Since a part is taken will relation to the whole, it is in the same genus as the whole. But the soul is called only a potential (potentialis) whole. Therefore, the different parts of soul are different powers (potentiae). But higher and lower reason are given by Augustine as different parts of reason. Therefore, they are different powers.
3. Everything eternal is necessary and everything temporal and subject to change is contingent, as appears from the Philosopher. But the Philosopher cans scientific the part of the soul which deals will necessary things, and reasoning, or conjectural, the part which deals will contingent things. Therefore, since, according to Augustine, higher reason embraces eternal things and lower reason administers temporal and perishable things, it seems that the reasoning is the same as lower reason and the scientific is the same as higher reason. But the scientific and reasoning are different powers, as the Philosopher also clearly shows. Therefore, higher and lower reason are different powers.
4. The Philosopher says that we must distinguish different powers of the soul for those things which are generically different, since every power of the soul which is limited to some genus is limited to it because of some likeness. Thus, the very diversity of objects according to genus bears witness to diversity of powers. But that which is eternal and that which is corruptible are entirely different generically, since corruptible and incorruptible do not belong to the same genus, as is said in the Metaphysics. Therefore, higher reason, whose object is eternal things, is a different power from lower reason, which has perishable things for its material object.
5. Powers are distinguished through acts, and acts through objects.
But truth to be contemplated is a different object from good to be done. Therefore, higher reason, which contemplates truth, is a different power from lower reason, which is occupied will the good.
6. That which is not one in itself is much less one when compared will something else. But higher reason is not one power, but several, since the image which consists of the three powers exists in it. There fore, it cannot be said that lower and higher reason are the one power.
7. Reason is more simple than sense. However, in sense we do not find that the same power has different functions. Therefore, in the intellective part one power is much less able to have different functions. But higher and lower reason "are double in their functions," as Augustine says. Therefore, they are different powers.
8. Whenever things which are not reduced to the same principle are attributed to the soul, we must assign different powers in the soul ac cording to this difference. Thus, imagination is distinguished from sense according to reception and retention. But the eternal and the corruptible cannot be reduced to the same principle. For, as is proved the Metaphysics, the proximate principles for corruptible and in corruptible things are not the same. Therefore, they should not be attributed to the same power of the soul. Thus, higher and lower reason are different powers.
9. Augustine says that through the three that cooperated in man’s sin—man, woman, and serpent—three things in us are indicated, namely, higher and lower reason and sensuality. But sensuality is a different power from lower reason. Therefore, lower reason, too, is different from higher reason.
10. One power cannot at the same time sin and not sin. But, some times, lower reason sins when higher reason does not, as is clear from Augustine. Therefore, lower reason and higher reason are not one power.
11. Different perfections belong to different subjects of perfection, since a proper act requires a proper power. But habits of the soul are perfections of its powers. Therefore, different habits belong to different powers. But, according to Augustine, higher reason is assigned for wisdom and lower reason for scientific knowledge, and these two are different habits. Therefore, higher and lower reason are different powers.
12. Every power is perfected through its act. But diversity of acts leads to or manifests diversity of powers. Therefore, wherever there is diversity of acts, we should conclude to diversity of powers. But higher and lower reason have different acts, since "they are double in their functions," as Augustine says. Therefore, they are different powers.
13. Higher and lower reason differ more than the agent and the possible intellect, since we see that the act of the agent and the possible intellect concern the same intelligible thing. But, as has been said, the acts of higher and lower reason do not concern the same thing, but different things. However, the agent and the possible intellect are different powers. Therefore, higher and lower reason are, too.
14. Everything that is drawn from something differs from it, for nothing is its own cause. But lower reason is drawn from higher reason, as Augustine says. Therefore, it is a different power from higher reason.
15. Nothing is moved by itself, as is proved in the Physics. But higher reason moves lower reason in so far as it directs and governs it. Therefore, higher and lower reason are different powers.
To the Contrary:
I’. Different powers of the soul are different things. But higher and lower reason are not different things. Consequently, Augustine says: "When we discuss the nature of the human mind, we are talking about one thing. And we divide it into the two which we have mentioned only by reason of its functions." Therefore, higher and lower reason are not different powers.
2'. The more immaterial a power is, the more it can extend to many things. But reason is more immaterial than sense. Yet, by the same sensitive power, sight, for example, we discern eternal things, either incorruptible or perpetual, namely the heavenly bodies, and corruptible things, as these lower things around us. Therefore, it is the same power of reason which contemplates eternal things and administers temporal things.
143
Before we can explain this question we have to know two things: how powers are distinguished, and how higher and lower reason differ. From these two we will be able to clarify the third point, which is the subject of our present inquiry, namely, whether higher and lower reason are one power or different powers.
We must bear in mind that diversity of powers is determined ac cording to acts and objects. However, some say that this is to be understood in the sense that diversity of acts and objects is only a sign of diversity of powers and not its cause. And others say that diversity of objects is the cause of diversity of powers in passive powers, but not in active powers.
But, if we study the matter carefully, we find that in both types of powers acts and objects are not only signs of diversity, but in some way causes of it. For every thing which has existence only because of some end has its manner determined for it from the end to which it is ordained. Thus, a saw has this kind of form and this kind of matter in order to be suitable for its end, which is to cut. But every power of the soul, whether active or passive, is ordained to act as to its end, as is clear in the Metaphysics. Hence, every power has a definite manner and species by reason of which it can be suitable for such an act. Therefore, powers are diversified because the diversity of acts required different principles from which to elicit acts. Moreover, since object is related to act as its term, and acts are specified by their terms, as is plain in the Physics, acts must also be distinguished according to their objects. Therefore, diversity of objects brings about diversity of powers.
Diversity of objects, however, can be regarded in two ways: ac cording to the nature of things and according to the diverse intelligible character of the objects. Diversity according to the nature of things appears in colour and taste; diversity according to intelligible character of object, in the good and the true. Moreover, since powers which are acts of definite organs cannot extend beyond the disposition of their organs (for one and the same physical organ cannot be suitable for knowledge of all natures), it is necessary that powers which are attached to organs be limited to certain natures, that is, to physical natures. For activity which is exercised through a physical organ cannot go beyond physical nature.
However, since there is something in corporeal nature in which all bodies agree, and something in which different bodies are diversified, it will be possible to make one power attached to the body suitable for all bodies according to that which they have in common. Thus, there is imagination for all bodies in so far as they share in the character of quantity, figure, and the things which follow on these. Hence, it ex- tends not only to physical objects, but also to mathematical objects. Similarly, there is common sense in so far as in all the physical bodies, to which alone it extends, there is a force which is active and productive of change [in the sense].
Some powers, however, are adapted to those aspects in which bodies are diversified by reason of a difference in the mode of producing change [in the sense]. Thus, sight relates to colour, hearing to sound, and so on for the other senses. From the fact that the sensitive part of the soul uses an organ in its activity two things follow: first, a power referring to an object common to all beings cannot be attributed to it, for this would immediately transcend physical reality; second, it is possible to find in the sensitive soul powers which differ according to the different nature of the objects because of the disposition of the organ, which can be suited to this or that nature.
But the part of the soul which does not use a physical organ in its activity does not remain limited, but is in a sense infinite, in so far as it is immaterial. Therefore, its power extends to an object common to all beings. Hence, the object of understanding is said to be "some thing" (quid), which is found in all classes of beings. For this reason, the Philosopher says: "Understanding is that by which one does all things and by which one becomes all things." Consequently, it is impossible to distinguish different powers in the intellective part according to different natures of the objects. We can do so only according to the different character of the object, that is to say, in so far as the act of the soul is directed to one and the same thing according to different relations at different times. Thus, goodness and truth in the intellective part distinguish understanding and will. For understanding is directed to intelligible truth as to a form, since it must be informed by that which is understood, and [the will] is directed to goodness as to an end.
For this reason, the Philosopher says that truth is in the mind and good in things, since form is inside and end is outside. Moreover, form and end do not perfect a thing for the same reason. Thus, goodness and truth do not have the same character of object.
It is in this way, too, that the understanding is divided into agent a possible intellect. For something is not an object for the same reason when it is in act and when it is in potency, or when it acts or is acted upon. For what is actually intelligible is the object of possible intellect and, as it were, acts upon it so that by the actually intelligible it proceeds from potency to act. But the potentially intelligible is the object of agent intellect, in so far as by reason of the agent intellect it becomes actually intelligible.
Therefore, it is clear how powers can be distinguished in the intellective part. And higher and lower reason are distinguished in this way. There are certain natures higher than the rational soul, and certain natures lower. But, since everything that is understood is understood in the manner of the one understanding, in the rational soul the act of understanding things above the soul is lower than the things under
stood; but for things beneath the soul there is in the soul an act of understanding which is higher than the things themselves, since the things have a more noble existence in the soul than they do in them selves. Thus, the soul has a different relation to both types of things, and from this the different functions are derived. For it is called higher reason in its reference to higher natures, either as contemplating their nature and truth in themselves, or as receiving from them intelligible character and a kind of model for activity. It is called lower reason in so far as it is directed to lower things either to perceive them through contemplation or to manage them through activity. Both types of nature, however, the higher and the lower, are perceived by the human soul in their common character of intelligible, the higher in so far as it is immaterial in itself, and the lower in so far as it is divested of matter through the activity of the soul.
From this it is clear that higher and lower reason are not different powers, but one and the same power which is related differently to different things.
Answers to Difficulties:
1. As we have said in the question on the mind, we see that the image of the Trinity in the soul is in the powers as in its root, but in its fullness it is in the acts of the powers. It is in this latter respect that the image is said to belong to higher and not to lower reason.
2. A part of a power does not always denote a distinct power, but, sometimes, a part of a power is taken according to part of the objects in so far as the virtual division of quantity is considered. Thus, if some one can carry one hundred pounds, one who can carry only fifty pounds is said to have part of that power, although the power is specifically the same. It is in this sense that higher and lower parts are called parts of reason in so far as they are directed to part of the objects to which reason, as the term is generally used, refers.
3. The scientific and the reasoning or conjectural parts are not the same as higher and lower reason, since we can have necessary considerations, which belong to the scientific, about lower natures will which lower reason is concerned; otherwise, physics and metaphysics would not be sciences; In the same way, higher reason also can in some way turn its attention to human acts, which depend on free will, and are contingent; otherwise, sin, which occurs in such matters, would not be attributed to higher reason. Thus, higher reason is not completely distinct from the reasoning or conjectural part.
But the scientific part and the reasoning part are different powers they are distinguished in relation to the nature of the intelligible object. For, since the act of any power does not extend beyond the scope of its object, every activity that cannot be reduced to the same formality of its object must belong to another power, which has another characteristic object. Now, the object of understanding is "something" (quid) as is said in The Soul. For this reason, the activity of understanding extends as far as the scope of the quiddity (quod quid est) of this "something" can extend. It is through this action that one at first knows principles themselves immediately, and from knowledge of these principles, by reasoning further, one arrives at knowledge of conclusions. This power, which is naturally ordained to analyze these conclusions into the quiddity (quod quid est), the Philosopher calls scientific.
However, there are some things in which it is impossible to perform such an analysis and to arrive at the quiddity, because of the uncertainty of their existence. This is the case will contingent things, in so far as they are contingent. Hence, these are not known through their quiddity, which is the proper object of understanding, but in another way, namely, through a kind of conjecture about those things concerning which we cannot have certitude. For this, then, a different power is needed. And, since this faculty cannot bring the inquiry of reason to its term, as it were, to rest, but stays will the investigation, as it were, in motion, and attains no more than opinion about the objects of its inquiry, this power is, therefore, called the reasoning or the conjectural power from the term of its activity. But higher and lower reason are distinguished according to natures themselves and, therefore, are not different powers as the scientific and the conjectural are.
4. The objects of the scientific and the reasoning parts are generically different by reason of the proper class of objects of knowledge, since they are known according to different intelligible characters. But eternal and temporal things differ in natural genus and not in their character of object of knowledge, according to which we must look for likeness between faculty and object.
5. Truth, which is the object of contemplation, and goodness, which is the object of activity, belong to different faculties, the understanding and the will. But higher and lower reason are not distinguished in this way, for both can be speculative and active, although by reason of different things, as has been shown above. Consequently, the conclusion does not follow.
6. Nothing prevents that which contains many things from being one will something else which contains many things if both contain the same things. Thus, this heap and this collection of stones are one and the same thing. In this way, higher and lower reason are the same faculty, although both in a sense contain several powers, since both contain the same powers. Moreover, higher reason is not said to include several powers in the sense that the power of reason itself is divided into different powers, but in so far as the will is included in the understanding. This does not mean that the will and the under standing are one faculty, but that the will is set in motion by the perception of the understanding.
7. Even in the sensitive part there is one power which has different functions, as the imagination, whose function it is to retain those things which have been received from the senses and represent them again to understanding. Accordingly, since the more immaterial a power is, the more things it can extend to, there is nothing to prevent one and the same power from having diverse functions in the intellective part, but not in the sensitive part.
8. Although the eternal and temporal are not reduced to the same proximate principle, knowledge of the eternal and of the temporal are reduced to the same principle since both are grasped according to one character of immateriality by one who understands.
9. According to Augustine, as man and woman, between whom there was the carnal marriage bond, belonged to human nature and the serpent did not, so lower reason, as woman, belongs to the nature of higher reason, whereas sensuality, as the serpent, does not.
10. Since sin is an act, properly speaking, it does not belong to either higher or lower reason, but to man according to the former or latter. And, if one power is related to different things, there is nothing in- consistent in having sin according to one relation and not according to the other. Thus, although several habits are in one power, it happens that one sins according to the act of one habit and not according to the act of another, for example, if the same man is grammarian and geometer, and lie makes a statement containing truth about limes and also a solecism.
11. When a perfection brings the perfectible thing to completion according to its full capacity, it is impossible for one perfectible thing to have several perfections in the same order. Therefore, matter can not receive perfection from two substantial forms at the same time, because one matter has a capacity for only one substantial nature. However, the case is different will accidental forms, which do not give perfection to their objects according to their full potency. Consequently, it is possible for one perfectible thing to have many accidents. Therefore, there can be many habits of one power, since habits are accidental perfections of powers, for they are superadded to the nature of the complete power.
2. As Avicenna says, diversity of act sometimes indicates diversity of powers and sometimes does not. For there can be diversity in the acts of the soul in five ways. In one, it is according to strength and weakness, as to conjecture and to believe. In the second, it is according to swiftness and slowness, as to run and to be put in motion. In the third, it is according to habit and privation, as to be at rest and to be moved. In the fourth, it is according to relation to opposites of the same genus, as to sense white and to sense black. It is in the fifth when the acts belong to different genera, as w perceive and to move, or to sense sound and w sense colour.
Accordingly, diversity of the first and second type does not manifest diversity of power, for it thus would be necessary to have as many distinct powers of soul as there are grades of strength or weakness and swiftness or slowness in acts. Similarly, diversity of the third and fourth type does not indicate diversity of power, since it belongs to the same power to occupy itself will both opposites. Hence, only diversity of the fifth type manifests diversity of power, so that we say that acts are generically different which do not agree in the character of their object. The diversity of acts of higher and lower reason does not display diversity of power in this way, as is clear from what has been said.
3. Agent and possible intellect differ more than higher and lower reason, since agent and possible intellect refer to objects formally different, although not materially different. For they refer to a different character of object, although both can be found in the same intelligible thing. For one and the same thing can first be intelligible in potency and then intelligible in act. But higher and lower reason refer to objects materially different, but not formally different. For they refer to different natures according to one character of object, as is clear from what has been said. But formal diversity is greater than material diversity. Therefore, the conclusion does not follow.
14. Lower reason is said to be drawn from higher reason because of the things which lower reason perceives, for these are drawn from those which higher reason perceives. For lower natures are drawn from higher natures. Consequently, nothing prevents higher and lower reason from being the same power. Similarly, we see that it belongs to the same power to study the principles of a sub-alternating science and the principles of a subalternate science, although the latter are drawn from the former.
15. Higher reason is said to move lower reason to this extent, that lower natures must be ruled according w higher natures, just as a subalternate science is ruled by the subalternating science.
Parallel readings: II Sentences 24, 3, 1; Summa Theol., I-II, 15, 4; 74, 7.
Difficulties:
It seems that it cannot, for
2. The Philosopher says: "The understanding is always correct." But reason is the same power as understanding, as was shown earlier. Therefore, reason is always correct. Therefore, there is no sin in it.
2. If anything that is receptive of some perfection is subject to defect, only the defect which is opposite to the perfection can exist in it, since the same thing is receptive of contraries. But, according to Augustine, wisdom is the proper perfection of higher reason, and science is the proper perfection of lower reason. Therefore, stupidity and ignorance can be the only sins in higher or lower reason.
3. According to Augustine, all sin is in the will. But reason is a different power from the will. Therefore, sin is not in reason.
4. Nothing is receptive of its opposite, for opposites cannot exist together. But every Sin of man is contrary to reason, for the evil of man is to be contrary to reason, as Dionysius says. Therefore, sin cannot exist in reason.
5. A sin which is committed in regard to a certain subject matter cannot be attributed to the power which does not extend to that matter. But higher reason has eternal things and not delights of the flesh for its subject matter. Therefore, sins concerning pleasures of the flesh ought not in any way be attributed w higher reason, even though Augustine says that consent to an act is attributed to higher reason.
6. Augustine says that it is higher reason which contemplates higher things and clings to them, namely, through love. But sin does not re suit from this. Therefore, sin cannot exist in higher reason.
7. The stronger is not overcome by the weaker. But reason is the strongest of the powers which we have within us. Therefore, it cannot be overcome by concupiscence or anger or something else of that sort. Therefore, sin cannot exist in it.
To the Contrary:
1'. Merit and demerit belong to the same thing. But merit resides in the act of reason. Therefore, so does demerit.
2’. According to the Philosopher sin comes not only from passion, but also from choice. But choice consists in an act of reason, since it follows deliberation, as is said in the Ethics. Therefore, there is sin in reason.
3’. Through reason we are directed in speculative and in practical matters. But in speculative matters there is sin of reason, as when one is guilty of paralogism in his reasoning. Therefore, in practical matters, also, there is sin in reason.
De veritate EN 142