Of the Intellectual Powers

Of the Intellectual Powers — St. Thomas Aquinas asks: Whether the intellect is a power of the soul?; Whether the intellect is a passive power?; Whether there is an active intellect?; Whether the active intellect is something in the soul?; Whether the active intellect is one in all?; Whether memory is in the intellectual part of the soul?; Whether the intellectual memory is a power distinct from the intellect?; Whether the reason is distinct from the intellect?; Whether the higher and lower reason are distinct powers?; Whether intelligence is a power distinct from intellect?; Whether the speculative and practical intellects are distinct powers?; Whether synderesis is a special power of the soul distinct from the others?; Whether conscience be a power?.

The next question concerns the intellectual powers, under which head there are thirteen points of inquiry:

Article 1: Whether the intellect is a power of the soul?

The Philosopher assigns the intellectual faculty as a power of the soul (De Anima ii, 3).

In accordance with what has been already shown (; ) it is necessary to say that the intellect is a power of the soul, and not the very essence of the soul. For then alone the essence of that which operates is the immediate principle of operation, when operation itself is its being: for as power is to operation as its act, so is the essence to being. But in God alone His action of understanding is His very Being. Wherefore in God alone is His intellect His essence: while in other intellectual creatures, the intellect is power.

Article 2: Whether the intellect is a passive power?

The Philosopher says (De Anima iii, 4) that "to understand is in a way to be passive."

To be passive may be taken in three ways. Firstly, in its most strict sense, when from a thing is taken something which belongs to it by virtue either of its nature, or of its proper inclination: as when water loses coolness by heating, and as when a man becomes ill or sad. Secondly, less strictly, a thing is said to be passive, when something, whether suitable or unsuitable, is taken away from it. And in this way not only he who is ill is said to be passive, but also he who is healed; not only he that is sad, but also he that is joyful; or whatever way he be altered or moved. Thirdly, in a wide sense a thing is said to be passive, from the very fact that what is in potentiality to something receives that to which it was in potentiality, without being deprived of anything. And accordingly, whatever passes from potentiality to act, may be said to be passive, even when it is perfected. And thus with us to understand is to be passive. This is clear from the following reason. For the intellect, as we have seen above (), has an operation extending to universal being. We may therefore see whether the intellect be in act or potentiality by observing first of all the nature of the relation of the intellect to universal being. For we find an intellect whose relation to universal being is that of the act of all being: and such is the Divine intellect, which is the Essence of God, in which originally and virtually, all being pre-exists as in its first cause. And therefore the Divine intellect is not in potentiality, but is pure act. But no created intellect can be an act in relation to the whole universal being; otherwise it would needs be an infinite being. Wherefore every created intellect is not the act of all things intelligible, by reason of its very existence; but is compared to these intelligible things as a potentiality to act.

Now, potentiality has a double relation to act. There is a potentiality which is always perfected by its act: as the matter of the heavenly bodies (). And there is another potentiality which is not always in act, but proceeds from potentiality to act; as we observe in things that are corrupted and generated. Wherefore the angelic intellect is always in act as regards those things which it can understand, by reason of its proximity to the first intellect, which is pure act, as we have said above. But the human intellect, which is the lowest in the order of intelligence and most remote from the perfection of the Divine intellect, is in potentiality with regard to things intelligible, and is at first "like a clean tablet on which nothing is written," as the Philosopher says (De Anima iii, 4). This is made clear from the fact, that at first we are only in potentiality to understand, and afterwards we are made to understand actually. And so it is evident that with us to understand is "in a way to be passive"; taking passion in the third sense. And consequently the intellect is a passive power.

Article 3: Whether there is an active intellect?

The Philosopher says (De Anima iii, 5), "As in every nature, so in the soul is there something by which it becomes all things, and something by which it makes all things." Therefore we must admit an active intellect.

According to the opinion of Plato, there is no need for an active intellect in order to make things actually intelligible; but perhaps in order to provide intellectual light to the intellect, as will be explained farther on (). For Plato supposed that the forms of natural things subsisted apart from matter, and consequently that they are intelligible: since a thing is actually intelligible from the very fact that it is immaterial. And he called such forms "species or ideas"; from a participation of which, he said that even corporeal matter was formed, in order that individuals might be naturally established in their proper genera and species: and that our intellect was formed by such participation in order to have knowledge of the genera and species of things. But since Aristotle did not allow that forms of natural things exist apart from matter, and as forms existing in matter are not actually intelligible; it follows that the natures of forms of the sensible things which we understand are not actually intelligible. Now nothing is reduced from potentiality to act except by something in act; as the senses as made actual by what is actually sensible. We must therefore assign on the part of the intellect some power to make things actually intelligible, by abstraction of the species from material conditions. And such is the necessity for an active intellect.

Article 4: Whether the active intellect is something in the soul?

The Philosopher says (De Anima iii, 5), that "it is necessary for these differences," namely, the passive and active intellect, "to be in the soul."

The active intellect, of which the Philosopher speaks, is something in the soul. In order to make this evident, we must observe that above the intellectual soul of man we must needs suppose a superior intellect, from which the soul acquires the power of understanding. For what is such by participation, and what is mobile, and what is imperfect always requires the pre-existence of something essentially such, immovable and perfect. Now the human soul is called intellectual by reason of a participation in intellectual power; a sign of which is that it is not wholly intellectual but only in part. Moreover it reaches to the understanding of truth by arguing, with a certain amount of reasoning and movement. Again it has an imperfect understanding; both because it does not understand everything, and because, in those things which it does understand, it passes from potentiality to act. Therefore there must needs be some higher intellect, by which the soul is helped to understand.

Wherefore some held that this intellect, substantially separate, is the active intellect, which by lighting up the phantasms as it were, makes them to be actually intelligible. But, even supposing the existence of such a separate active intellect, it would still be necessary to assign to the human soul some power participating in that superior intellect, by which power the human soul makes things actually intelligible. Just as in other perfect natural things, besides the universal active causes, each one is endowed with its proper powers derived from those universal causes: for the sun alone does not generate man; but in man is the power of begetting man: and in like manner with other perfect animals. Now among these lower things nothing is more perfect than the human soul. Wherefore we must say that in the soul is some power derived from a higher intellect, whereby it is able to light up the phantasms. And we know this by experience, since we perceive that we abstract universal forms from their particular conditions, which is to make them actually intelligible. Now no action belongs to anything except through some principle formally inherent therein; as we have said above of the passive intellect (). Therefore the power which is the principle of this action must be something in the soul. For this reason Aristotle (De Anima iii, 5) compared the active intellect to light, which is something received into the air: while Plato compared the separate intellect impressing the soul to the sun, as Themistius says in his commentary on De Anima iii. But the separate intellect, according to the teaching of our faith, is God Himself, Who is the soul's Creator, and only beatitude; as will be shown later on (; ). Wherefore the human soul derives its intellectual light from Him, according to Ps. 4:7, "The light of Thy countenance, O Lord, is signed upon us."

Article 5: Whether the active intellect is one in all?

The Philosopher says (De Anima iii, 5) that the active intellect is as a light. But light is not the same in the various things enlightened. Therefore the same active intellect is not in various men.

The truth about this question depends on what we have already said (). For if the active intellect were not something belonging to the soul, but were some separate substance, there would be one active intellect for all men. And this is what they mean who hold that there is one active intellect for all. But if the active intellect is something belonging to the soul, as one of its powers, we are bound to say that there are as many active intellects as there are souls, which are multiplied according to the number of men, as we have said above (). For it is impossible that one same power belong to various substances.

Article 6: Whether memory is in the intellectual part of the soul?

Augustine says (De Trin. x, 11) that "memory, understanding, and will are one mind."

Since it is of the nature of the memory to preserve the species of those things which are not actually apprehended, we must first of all consider whether the intelligible species can thus be preserved in the intellect: because Avicenna held that this was impossible. For he admitted that this could happen in the sensitive part, as to some powers, inasmuch as they are acts of corporeal organs, in which certain species may be preserved apart from actual apprehension. But in the intellect, which has no corporeal organ, nothing but what is intelligible exists. Wherefore every thing of which the likeness exists in the intellect must be actually understood. Thus, therefore, according to him, as soon as we cease to understand something actually, the species of that thing ceases to be in our intellect, and if we wish to understand that thing anew, we must turn to the active intellect, which he held to be a separate substance, in order that the intelligible species may thence flow again into our passive intellect. And from the practice and habit of turning to the active intellect there is formed, according to him, a certain aptitude in the passive intellect for turning to the active intellect; which aptitude he calls the habit of knowledge. According, therefore, to this supposition, nothing is preserved in the intellectual part that is not actually understood: wherefore it would not be possible to admit memory in the intellectual part.

But this opinion is clearly opposed to the teaching of Aristotle. For he says (De Anima iii, 4) that, when the passive intellect "is identified with each thing as knowing it, it is said to be in act," and that "this happens when it can operate of itself. And, even then, it is in potentiality, but not in the same way as before learning and discovering." Now, the passive intellect is said to be each thing, inasmuch as it receives the intelligible species of each thing. To the fact, therefore, that it receives the species of intelligible things it owes its being able to operate when it wills, but not so that it be always operating: for even then is it in potentiality in a certain sense, though otherwise than before the act of understanding---namely, in the sense that whoever has habitual knowledge is in potentiality to actual consideration.

The foregoing opinion is also opposed to reason. For what is received into something is received according to the conditions of the recipient. But the intellect is of a more stable nature, and is more immovable than corporeal nature. If, therefore, corporeal matter holds the forms which it receives, not only while it actually does something through them, but also after ceasing to act through them, much more cogent reason is there for the intellect to receive the species unchangeably and lastingly, whether it receive them from things sensible, or derive them from some superior intellect. Thus, therefore, if we take memory only for the power of retaining species, we must say that it is in the intellectual part. But if in the notion of memory we include its object as something past, then the memory is not in the intellectual, but only in the sensitive part, which apprehends individual things. For past, as past, since it signifies being under a condition of fixed time, is something individual.

Article 7: Whether the intellectual memory is a power distinct from the intellect?

From its nature the memory is the treasury or storehouse of species. But the Philosopher (De Anima iii) attributes this to the intellect, as we have said (). Therefore the memory is not another power from the intellect.

As has been said above (), the powers of the soul are distinguished by the different formal aspects of their objects: since each power is defined in reference to that thing to which it is directed and which is its object. It has also been said above () that if any power by its nature be directed to an object according to the common ratio of the object, that power will not be differentiated according to the individual differences of that object: just as the power of sight, which regards its object under the common ratio of color, is not differentiated by differences of black and white. Now, the intellect regards its object under the common ratio of being: since the passive intellect is that "in which all are in potentiality." Wherefore the passive intellect is not differentiated by any difference of being. Nevertheless there is a distinction between the power of the active intellect and of the passive intellect: because as regards the same object, the active power which makes the object to be in act must be distinct from the passive power, which is moved by the object existing in act. Thus the active power is compared to its object as a being in act is to a being in potentiality; whereas the passive power, on the contrary, is compared to its object as being in potentiality is to a being in act. Therefore there can be no other difference of powers in the intellect, but that of passive and active. Wherefore it is clear that memory is not a distinct power from the intellect: for it belongs to the nature of a passive power to retain as well as to receive.

Article 8: Whether the reason is distinct from the intellect?

Augustine says (Gen. ad lit. iii, 20) that "that in which man excels irrational animals is reason, or mind, or intelligence or whatever appropriate name we like to give it." Therefore, reason, intellect and mind are one power.

Reason and intellect in man cannot be distinct powers. We shall understand this clearly if we consider their respective actions. For to understand is simply to apprehend intelligible truth: and to reason is to advance from one thing understood to another, so as to know an intelligible truth. And therefore angels, who according to their nature, possess perfect knowledge of intelligible truth, have no need to advance from one thing to another; but apprehend the truth simply and without mental discussion, as Dionysius says (Div. Nom. vii). But man arrives at the knowledge of intelligible truth by advancing from one thing to another; and therefore he is called rational. Reasoning, therefore, is compared to understanding, as movement is to rest, or acquisition to possession; of which one belongs to the perfect, the other to the imperfect. And since movement always proceeds from something immovable, and ends in something at rest; hence it is that human reasoning, by way of inquiry and discovery, advances from certain things simply understood---namely, the first principles; and, again, by way of judgment returns by analysis to first principles, in the light of which it examines what it has found. Now it is clear that rest and movement are not to be referred to different powers, but to one and the same, even in natural things: since by the same nature a thing is moved towards a certain place. Much more, therefore, by the same power do we understand and reason: and so it is clear that in man reason and intellect are the same power.

Article 9: Whether the higher and lower reason are distinct powers?

Augustine says (De Trin. xii, 4) that "the higher and lower reason are only distinct by their functions." Therefore they are not two powers.

The higher and lower reason, as they are understood by Augustine, can in no way be two powers of the soul. For he says that "the higher reason is that which is intent on the contemplation and consultation of things eternal": forasmuch as in contemplation it sees them in themselves, and in consultation it takes its rules of action from them. But he calls the lower reason that which "is intent on the disposal of temporal things." Now these two---namely, eternal and temporal ---are related to our knowledge in this way, that one of them is the means of knowing the other. For by way of discovery, we come through knowledge of temporal things to that of things eternal, according to the words of the Apostle (Rom. 1:20), "The invisible things of God are clearly seen, being understood by the things that are made": while by way of judgment, from eternal things already known, we judge of temporal things, and according to laws of things eternal we dispose of temporal things.

But it may happen that the medium and what is attained thereby belong to different habits: as the first indemonstrable principles belong to the habit of the intellect; whereas the conclusions which we draw from them belong to the habit of science. And so it happens that from the principles of geometry we draw a conclusion in another science---for example, perspective. But the power of the reason is such that both medium and term belong to it. For the act of the reason is, as it were, a movement from one thing to another. But the same movable thing passes through the medium and reaches the end. Wherefore the higher and lower reasons are one and the same power. But according to Augustine they are distinguished by the functions of their actions, and according to their various habits: for wisdom is attributed to the higher reason, science to the lower.

Article 10: Whether intelligence is a power distinct from intellect?

The Philosopher says (De Anima iii, 6) that "intelligence is of indivisible things in which there is nothing false." But the knowledge of these things belongs to the intellect. Therefore intelligence is not another power than the intellect.

This word "intelligence" properly signifies the intellect's very act, which is to understand. However, in some works translated from the Arabic, the separate substances which we call angels are called "intelligences," and perhaps for this reason, that such substances are always actually understanding. But in works translated from the Greek, they are called "intellects" or "minds." Thus intelligence is not distinct from intellect, as power is from power; but as act is from power. And such a division is recognized even by the philosophers. For sometimes they assign four intellects---namely, the "active" and "passive" intellects, the intellect "in habit," and the "actual" intellect. Of which four the active and passive intellects are different powers; just as in all things the active power is distinct from the passive. But three of these are distinct, as three states of the passive intellect, which is sometimes in potentiality only, and thus it is called passive; sometimes it is in the first act, which is knowledge, and thus it is called intellect in habit; and sometimes it is in the second act, which is to consider, and thus it is called intellect in act, or actual intellect.

Article 11: Whether the speculative and practical intellects are distinct powers?

The speculative intellect by extension becomes practical (De Anima iii, 10). But one power is not changed into another. Therefore the speculative and practical intellects are not distinct powers.

The speculative and practical intellects are not distinct powers. The reason of which is that, as we have said above (), what is accidental to the nature of the object of a power, does not differentiate that power; for it is accidental to a thing colored to be man, or to be great or small; hence all such things are apprehended by the same power of sight. Now, to a thing apprehended by the intellect, it is accidental whether it be directed to operation or not, and according to this the speculative and practical intellects differ. For it is the speculative intellect which directs what it apprehends, not to operation, but to the consideration of truth; while the practical intellect is that which directs what it apprehends to operation. And this is what the Philosopher says (De Anima iii, 10); that "the speculative differs from the practical in its end." Whence each is named from its end: the one speculative, the other practical---i.e. operative.

Article 12: Whether synderesis is a special power of the soul distinct from the others?

According to the Philosopher (Metaph. viii, 2), "rational powers regard opposite things." But "synderesis" does not regard opposites, but inclines to good only. Therefore "synderesis" is not a power. For if it were a power it would be a rational power, since it is not found in brute animals.

"Synderesis" is not a power but a habit; though some held that it is a power higher than reason; while others [*Cf. Alexander of Hales, Sum. Theol. II, ] said that it is reason itself, not as reason, but as a nature. In order to make this clear we must observe that, as we have said above (), man's act of reasoning, since it is a kind of movement, proceeds from the understanding of certain things---namely, those which are naturally known without any investigation on the part of reason, as from an immovable principle---and ends also at the understanding, inasmuch as by means of those principles naturally known, we judge of those things which we have discovered by reasoning. Now it is clear that, as the speculative reason argues about speculative things, so that practical reason argues about practical things. Therefore we must have, bestowed on us by nature, not only speculative principles, but also practical principles. Now the first speculative principles bestowed on us by nature do not belong to a special power, but to a special habit, which is called "the understanding of principles," as the Philosopher explains (Ethic. vi, 6). Wherefore the first practical principles, bestowed on us by nature, do not belong to a special power, but to a special natural habit, which we call "synderesis." Whence "synderesis" is said to incite to good, and to murmur at evil, inasmuch as through first principles we proceed to discover, and judge of what we have discovered. It is therefore clear that "synderesis" is not a power, but a natural habit.

Article 13: Whether conscience be a power?

Conscience can be laid aside. But a power cannot be laid aside. Therefore conscience is not a power.

Properly speaking, conscience is not a power, but an act. This is evident both from the very name and from those things which in the common way of speaking are attributed to conscience. For conscience, according to the very nature of the word, implies the relation of knowledge to something: for conscience may be resolved into "cum alio scientia," i.e. knowledge applied to an individual case. But the application of knowledge to something is done by some act. Wherefore from this explanation of the name it is clear that conscience is an act.

The same is manifest from those things which are attributed to conscience. For conscience is said to witness, to bind, or incite, and also to accuse, torment, or rebuke. And all these follow the application of knowledge or science to what we do: which application is made in three ways. One way in so far as we recognize that we have done or not done something; "Thy conscience knoweth that thou hast often spoken evil of others" (Eccles. 7:23), and according to this, conscience is said to witness. In another way, so far as through the conscience we judge that something should be done or not done; and in this sense, conscience is said to incite or to bind. In the third way, so far as by conscience we judge that something done is well done or ill done, and in this sense conscience is said to excuse, accuse, or torment. Now, it is clear that all these things follow the actual application of knowledge to what we do. Wherefore, properly speaking, conscience denominates an act. But since habit is a principle of act, sometimes the name conscience is given to the first natural habit---namely, 'synderesis': thus Jerome calls 'synderesis' conscience (Gloss. Ezech. 1:6); Basil [*Hom. in princ. Proverb.], the "natural power of judgment," and Damascene [*De Fide Orth. iv. 22] says that it is the "law of our intellect." For it is customary for causes and effects to be called after one another.