Chapter 3

Having shown from the statements of Aristotle and of those following him, that the intellect is a power of the soul, which is the form of the body,—though this power which is called the intellect is not the act of any corporeal organ, because its operation does not involve any bodily operation, as Aristotle says—it is now our purpose to inquire into the reasons why this opinion must be held to be true. And since, according to the teaching of Aristotle, one ought to consider the principle of acts through its acts, it seems that our consideration should begin with that act which is properly the intellect's own—which is, to understand.

In regard to this we can have no more assured definition than that which Aristotle proposes: The soul is the principle by which we live and understand. Therefore it is also the specific form of a certain body. And to this reason he attributes such force that he speaks of it as a demonstration. In the beginning of the chapter he says: "To show what a thing is, one ought to give not only a comprehensive definition, as many do in defining terms, but one ought to show what the inner cause of a thing is, and demonstrate it." Then he gives an example: "Just as demonstration is given of what a tetragon or a square is, through the finding of a median proportional line."

The force of this kind of demonstration seems incontestible, because whoever would wish to turn aside from the road it points out must necessarily fall into inconsistency. Now it is evident that this individual man understands. Never, indeed, would we be inquiring about the intellect unless we possessed intelligence; and when we are carrying on our inquiries about the intellect we do not inquire about any other principle than that one by means of which we understand. Therefore Aristotle says: "I speak, moreover, of the intellect, by which the soul understands." And thus Aristotle concludes: "But if something is the first principle by which we understand, this must be the form of the body." This he says because he had previously made evident that that by which a thing first operates is the form. And this is clear through consideration of action, since each thing operates inasmuch as it is in act. Moreover, each thing is in act through its form; whence it follows that that by which it first acts must be the form.

If, however, one should say that the principle of this act of understanding, a principle that we have called the intellect, is not the form, then it is necessary to explain the way in which the action of this principle is the act of this man. To this problem certain philosophers have offered various explanations. One of these philosophers, Averroes, proposes that the principle of understanding, which he calls the possible intellect, is not the soul or a faculty of the soul, except equivocally; but rather, that it is a certain separated substance, as he has said: The understanding, which belongs to the separated substance, is my understanding or that of another, inasmuch as that possible intellect is united to me or to you through the phantasms which are in me or in you. Thus, he says, the process of understanding comes about. For the intelligible species, which becomes one with the possible intellect since it is its form and its act, has two subjects: one is the phantasm, the other is the possible intellect. Therefore, he says, the possible intellect establishes a continuity with us through its form, the phantasms acting as intermediaries; and thus, while the possible intellect understands, this man understands.

Three reasons, however, show clearly that this doctrine is not true. First because, if this were the case, the union of the intellect with man would not be from the first moment of his generation, as Theophrastus says it is, and as Aristotle implies in II Physic., where he says: The natural term of consideration about forms is for the form, according as man is generated by man and the sun. It is clear, moreover, that the natural term of consideration is the intellect; but, according to the doctrine of Averroes, the intellect is not united to man by reason of his generation, but according to the operation of his senses, inasmuch as he is in act as a sentient being: "For the phantasm is activated by the senses according to their act," as is said in the Third Book of the De anima.

Secondly because this union would not be in relation to any one thing, but according to different things. Now, it is evident that the intelligible species, according as it resides in phantasms, is intelligible potentially. In the possible intellect, however, it is intelligible in act, inasmuch as it has been abstracted from the phantasms. If, therefore, the intelligible species is not the form of the possible intellect, except as abstracted from phantasms, it follows that through the intelligible species there is no conjunction of the intellect with the phantasms, but rather it is separate from these images; unless, perhaps, we should say that the possible intellect is continuous with the phantasms, just as a mirror is united to a man whose reflection happens to be in the mirror. But such a kind of union clearly does not suffice to explain united action. For evidently what is the act of the mirror, namely, to reflect, cannot on this account be attributed to the man reflected; wherefore neither can the action of the possible intellect, according to the type of union proposed, be attributed to this man-for example, to Socrates—in such a way that this man should understand.

Thirdly because, granting that one and the same species, numerically, would be the form of the possible intellect and yet be simultaneously in the phantasm, still, it would not suffice to explain how this man would understand. Evidently, through the intelligible species there is something to be understood, but through the possible intellect man understands that thing; just as also through the sensible species something is perceived, but it is through the sense faculty that one experiences sensation. In like manner a wall on which there is color—the sensible species of which is in act in vision—is seen but does not itself see; but an animal having a visual faculty in which this sensible species is possessed, does see. Now, the proposed conjunction of the possible intellect with a man possessing in his imagination phantasms whose intelligible species reside in the possible intellect, would be like the union of the wall, on which there is color, with the eye, in which the species of its color would reside. Just as the wall, therefore, does not see—but its-color is seen—so it would follow that man would not understand, but the phantasms that are his would be understood by the possible intellect. It is impossible, therefore, to explain, according to the position of Averroes, how any man would understand.

But some philosophers, indeed, seeing that the conclusions reached by Averroes' road could not show how this individual man thinks, have turned aside into another road. They say that the intellect is united to man as a mover; and so, inasmuch as unity is produced by the conjunction of body and. intellect, as by the union of a mover and the thing moved, so the intellect is a part of this man. Hence the operation of the intellect is attributed to the man, just as the operation of the eye, which is to see, is attributed to him. It must be asked, however, of one holding this theory, first of all, what kind of individual this is whom we call Socrates. Is Socrates the intellect alone—that is, the mover (motor)? Or is he moved by that which is the body, and yet animated by a vegetative and sensitive soul? Or is he a composite of both? It seems from their position that the third opinion should be held: namely, that Socrates is a being composed of both.

Let us, therefore, proceed against them through the statement of Aristotle in VIII Metaph., where he says: "Now, when anything has parts, not as an aggregation but as a unified whole, there is in the totality besides the parts something that is distinguished as the cause of unity; as in some bodies the cause of the unity of the being is vitality; in others, the humors, or some other modification of being. "But such a being (as Socrates) is a substance of a unique nature, not after the manner of Ilias, a city composed of parts, but a being of one existence. What is it, therefore, that makes a man one, in virtue of which he is unified and not multiple for example, so that one part of him might be 'animal' and the other 'biped' (although there are some who say that this is the case: that he is truly an animal and truly a biped in such a way that the two are really distinct)? "According to this view, man is not both these things, but they will be, by participation, men—not the attributes, of one man, but of two: the one, animal; the other, biped. And the ensemble will not constitute a man who is one and yet multiple—animal and biped. Hence undoubtedly (because some have been accustomed so to define man and so to teach their hearers) this doctrine does not solve the difficulty. But if, as we have said, this one thing is matter, and that other, form—the one in potency, and the other in act—then the problem no longer seems to exist."

But if you say that Socrates is not an absolutely unified being, but a unity of a sort resulting from the aggregation of mover and moved, many difficulties would result. First of all, because if anything is one in so far as and in the same way as it is being, it would follow that Socrates would not be anything, that he would not be in any species or genus, and that further he would not have any action, since there is no action except that of a being. Consequently we do not say that the sailor’s ability to understand is attributable to the totality comprised by the sailor and his ship, but that understanding belongs to the sailor alone; and in like manner (according to the foregoing supposition) to understand will not be the act of Socrates, but of the intellect alone which makes use of the body of Socrates. For only in that totality which is a unity is the action of a part the action of the whole and if anyone says otherwise, he speaks inaccurately.

And if you say that it is in this manner that the heaven understands, namely, through a mover, such an assumption only provides the matter of further difficulty; for what we know of the human intellect ought to be our means of attaining to knowledge about superior intellects, and not contrariwise.

But if it is said that this individual, that is, Socrates, is a body animated by a vegetative and sensitive soul, as seems to follow according to those who hold that this man is not specifically constituted by his intellect but by a sensitive soul which is in some way ennobled by the influence of the possible intellect, then the intellect will not be related to Socrates except as a mover is related to that which is moved. According to this theory, however, the act of the intellect, which is to understand, can in no way be attributed to Socrates, as is apparent for various reasons:

First because of what the Philosopher says in II Metaph.: "In those things in which there is diversity between some work and the action producing it, the action is in that which is produced, as the act of building is in that which is built, and the act of weaving is in the cloth; and similarly in other things of the same order, the mover is wholly in the thing moved. But in the case of those things in which there is no product apart from the action, the action is in the beings producing the action, as light is in the one who sees, and a reflection is in the mirror which reflects." Thus, therefore, even if it is granted that an intellect is united to Socrates as moving him, this does not prove that understanding is in Socrates, or that he understands; because understanding is an act which is in the intellect alone. Therefore it is also false to say, as they do, that the intellect is not the act of the body, but that man himself understands. For it is not possible that understanding should be attributed to a being that has not an act [form] which is intellectual; because intellection can only be in an intellect, as vision in an eye; wherefore there can be no vision except in one whose act is visual [whose substantial form makes vision possible].

Secondly because the action of a mover is not properly attributed to an instrument or to the being moved; on the contrary, the action of the instrument is attributed to the principal efficient cause. For it is not possible to say that a saw uses or controls the artisan; whereas it is possible to say that the artisan saws, although the work is that of the saw. Now, the proper operation of the intellect is to understand. Therefore, even if it is granted that the act of understanding may be transient, passing over into another so as to move it to understand, it still would not follow that understanding would belong to Socrates, if the intellect were united to him only as a mover.

Thirdly because, in the case of those things whose actions are transient, passing over into another, these actions are attributed in contrary ways to the causes of motion and to the things moved. Accordingly a builder is said to erect a building, but the building is said to be erected. Therefore, if understanding, just as motion, should be transient action, passing over into another, still it could not be said that Socrates understands, inasmuch as intellect is united to him as a mover; but rather, it must be said that intellect understands, and that Socrates is understood; or that intellect, by means of Socrates who has been rendered intelligent, moves Socrates, and thus again, Socrates is moved.

Nevertheless it sometimes happens that the action of an efficient cause passes over into the thing moved: for example, when that which is moved, in virtue of that by which it is moved, initiates movement in another—just as something in which heat has been engendered, engenders heat. Therefore some one might be able to say that, though moved by intellect, man in the act of understanding initiates motion, so that from the very fact that he is moved, he understands. This opinion, however, Aristotle opposes in II De anima, from which we have gleaned the principle of his argument. For, after saying that it is primarily by means of a form that we know and that we possess health, namely, the form of science and the form of health, he adds: "Acts, indeed, appear to be in the patient and in the subject of modification," as Themistius in explaining this says. "For, although science and health are, in a certain way, from others—for example, from a teacher and from a physician—nevertheless, in the patient and in his disposition for modification there reside acts which we have shown to be prior, since they are in them by nature." It is, therefore, the intention of Aristotle—and, moreover, it is evidently true—that when one thing moves another and possesses the action of a mover, there must be in it some act from the mover, who has this sort of act; and this is the principle by which it operates, and it is both its act and form; just is in it from its own enkindling agent.

Granted, therefore, that the intellect may move the soul of Socrates either by illuminating it or in any other way, what results in Socrates from the influence of the intellect is that by which he first understands. Moreover, that by which, primarily, Socrates understands (just as by his senses he experiences sensation), Aristotle proves to be in potency to all things and accordingly to have no natural determination except this: that it is "possible" and therefore with no admixture of anything corporeal, but separate. If it is conceded that some separate intellect moves Socrates, nevertheless it still must be maintained that this possible intellect of which Aristotle speaks is in the soul of Socrates, just as the sense faculties are, which are in potency to all the sensible things that Socrates perceives.

If, however, it is said that this individual man, Socrates, is not a being composed of intellect and animate body, and that he is not merely an animate body, but that he is intellect alone then this will be to state the opinion of Plato who, as Gregory of Nyssa tells us, on account of this difficulty did not wish to consider man as consisting of soul and body, but of a soul using a body, and wearing the body, as it were, as one would a garment. Plotinus also, as Macrobius indicates, held that man was a being of this kind, when he said: "The true man us not he who appears to the eyes, but he by whom the one seen is ruled. Thus, when at death animal life departs from the body, the latter, widowed of its ruler, undergoes dissolution; and this body is what appears mortal in man. The soul. however, which is the true man, is an alien to all conditions of mortality." Now, this same Plotinus, one of the great commentators, is listed among those of Aristotle, as Simplicius states in his commentary, Praedicamentorum.

Moreover, this opinion does not seem to be in conflict with the words of Aristotle. For he says in IX Ethic., "It is the part of a good man to be zealous for the good, even by the grace which is his own. For intellect appears to be a grace possessed by every man." But he does not, indeed, on this account say that man is intellect alone, but that what holds the chief place in man is his intellect. Wherefore he subsequently says: "Just as a city-state, or any other organized society, appears to be the principal one, so does man." And to this he adds: "Every man either is this, intellect, or he is especially this." And in this latter sense, I think, the previously cited words of Themistius and those of Plotinus, just now quoted, were spoken when they said: Man is a soul, or intellect.

That man is not intellect alone, or soul alone, may be proved in many ways:

1. [On the basis of unity.] First, by Gregory of Nyssa himself who, after citing the opinion of Plato, adds: "This statement contains a problem which is difficult, or even without solution. For what kind of unity can a soul 'clothed in a body' be? It cannot be altogether simple while wearing this garment of flesh."

2. [Effects on the body.] Secondly, because Aristotle in VII Metaph. shows that "man" and "a horse" and similar things are not forms alone, but a kind of whole composed of form and matter: a unified, individual being is constituted of prime matter and form, as Socrates. Now, man also is similar to other things that are corporeal, and this Aristotle has proved by the fact that no part of the body can be said to be complete without some part or faculty of the soul; and, after the departure of the soul, one does not speak of an eye or of flesh except equivocally. But this would not be the case if man, or Socrates, were intellect alone, or only a soul.

3. [Relation to the will.] In the third place, it would follow that, since the intellect does not operate except by an act of the will (as is proved in III De anima), this would also be in the power of the will: namely, that a man should retain his body when he wished and abandon it when he wished, which very evidently is false.

Thus therefore it is clear that the intellect is not united to Socrates as a mover only, and that even if this should be so, it could not explain the fact that Socrates understands. Consequently those who wish to defend this position must either confess that they themselves understand nothing and so are disqualified from disputing about anything, or they must admit the truth of what Aristotle concludes: That by which we first understand is the species and the form.

This same conclusion can also be derived from the fact that this individual man is assigned to a certain species; but no species is determined except on the basis of form; therefore that through which this man's species is determined is his form. 4. [Distinction of species.] Any species, moreover, is distinguished by that which is the principal operation proper to that species. But the proper act of man, inasmuch as he is man, is to understand. Through this he differs from other animals; hence Aristotle says that in this operation man's ultimate felicity consists. The principle by which we understand is the intellect, as Aristotle says. Therefore it must be united to the body as its form; not indeed in such a way that the possible intellect itself is the act of any bodily organ, but because it is a power of the soul, which is the act of the physically organized body.

5. [Moral effects,] Furthermore, in view of this false position, the principles of moral philosophy are destroyed. Indeed, whatever is in us [as attributable to us] is withdrawn. Now, nothing is in us as that for which we are accountable except through our willing it; wherefore that which is in our power is called "voluntary." The will, however, is in the intellect, as is clear from the statement of Aristotle in III De anima. It is evident also from the fact that in separate substances there is intellect and will; and likewise because it is in the power of the will to love or hate something in general, just as we hate all thieves as a class, as Aristotle says in his Rhetorica.

If, therefore, the intellect is not anything belonging to this man, or truly one with him, but united to him only through phantasms or as a mover (motor), there will be in man no will of his own, but it will reside in the separate intellect. Consequently this man will not be master of his own acts, nor will any act of his be laudable or blameworthy. But to accept such a view is to destroy the principles of moral philosophy. Since, however, such a thing would be absurd and contrary to human life (for in that case there would be no need to hold councils or to enact laws), it follows that the intellect is united to us in such a way that from it and from us a true unity is constituted. But this cannot come about except in the way that has been stated: namely, that the intellect also is one of the powers of the soul, which is united to us as our form. The conclusion is, therefore, that without any doubt this opinion should be held not only because of the revelation of faith, as they say, but also because to oppose it is to go against philosophical evidence which is clearly apparent.

It is not difficult to refute the reasons that some bring forward in opposition to this doctrine. There are those who maintain that, according to this position, it would follow that the intellect would be a material form and so not stripped of all the character of sensible things, and that consequently whatever is received in the intellect is received individually, as in matter, and not universally. They allege further that, if it is a material form, it is not actually intelligible and so the intellect cannot understand itself, though this is evidently false; for no material form is actually intelligible.

The solution of this difficulty is clear from what has previously been said. We do not say that the human soul is the form of the body according to the possible intellect, which, in the teaching of Aristotle, is not the act of any bodily organ. Therefore it remains true that the soul, as regards the possible intellect, is immaterial, is receptive of immaterial objects, and knows itself. Therefore also, Aristotle uttered these remarkable words about the soul: It is the locus of species—not the entire soul, but the intellect.

If, however, it should be objected that a faculty of the soul cannot be more immaterial than the essence, or more simple, then it may be said that the objection would be very well proposed if the essence of the human soul were a material form, which has no existence of its own, but only the existence of the composite—as is the case with other forms (below the human) which have of themselves neither existence nor operation apart from their communication with matter; and for this reason they are said to be immersed in matter. However, because the human soul by its essence is a form united with matter in such a way that matter does not entirely encompass [or absorb] it,—since the dignity of the form exceeds the capacity of matter—the soul is not hindered from having an operation or a power in which matter is not involved.

Anyone saying this should also consider that, if the intellective principle by which we understand should be essentially separate and distinct from the soul, which is the form of our body, it would be, by its very essence, intelligent and intelligible, and there would be no question of a time when it would understand and of another time when it would not. Nor would it require that it should know through intelligible objects or through acts, but it would have knowledge through its own essence, even as other separated substances. Neither would it be fitting that, to understand, it should have any need of our phantasms. For it is not found in the natural order of things that higher substances, to attain their principal perfection, depend upon inferior substances: so, for example, the heavenly bodies are not formed or fitted for their operations by inferior bodies.

Therefore grave error is contained in the opinion of anyone who says that the intellect is a kind of principle which is separate substantially, and yet that, through species received from phantasms, it is perfected and made intelligent in act.