Commentaria in Summam contra Gentiles, Liber II

After St. Thomas had determined the question of the union of the intellectual soul with the body, he now determines the question of its unity ¹. But since the possible intellect, by which the soul understands, is rooted in the very essence of the soul—on account of which, if it were posited as one for all men, one would have to say that there is one intellectual soul for all men—therefore, wishing to inquire into the unity of the intellectual soul, St. Thomas inquires into the unity of the possible intellect. And since the agent intellect also concurs in understanding, therefore, after his determination concerning the possible intellect, he inquires as well concerning the agent intellect, with respect to abstraction and unity, in chapter LXXVI.

He does two things concerning the possible intellect: first, he shows that it is not one intellect for all human beings, against Averroes, who held that there is one possible intellect for all men who are, who will be, and who have been; second, he resolves the arguments of the Averroists ².

I. As to the first, he argues first as follows. The substance of the intellect, that is, the substance in which the intellective power is rooted, is united to the human body as its form. Therefore there is not one intellect for all human beings. — The consequence is proved. For it is impossible for there to be one form except of one matter, since a proper act is in its proper matter, and they are proportionate to one another.

Note that when it is said that one form cannot be except of one matter, this must be understood of the matter which is the first perfectible by such a form. For such a matter is proportioned to the form, so that neither is the form found outside that perfectible, nor is the matter receptive of another form: for this matter requires this form, and this form requires this matter. But as for matter which is part of the first perfectible, there is no incongruity in one form informing several matters: for it was said above ³ that one soul is the act and form of all the parts of the body.

II. Second. The intellect is compared to the body as its mover, as is said in Book III of the De Anima. Therefore the intellect of one man is not the intellect of another. — The consequence is proved: because proper instruments are owed to each mover; for an architect does not use the instruments of a flute-player.

2. But this argument does not seem effective. Indeed, from the fact that the intellect is compared to the body as a mover, it seems that it would not be repugnant for one intellect to be in many men: for one mover can move many things movable.

It also seems that the proof of the consequence is invalid. For the parts of a human body are instruments of the intellect of one kind of one reason. But when the proposition is assumed, that proper instruments are owed to each mover, it is understood in this sense: that one craftsman does not use instruments belonging to another kind, as distinct from the instruments of another craft. Now, although one craftsman does not use the instruments of another craft, it does not follow that he cannot use numerically distinct instruments of the same craft. For the antecedent is true and the consequent false.

3. To the first it is replied that the argument is effective, if it is well understood. For although one mover can move diverse inadequate movable things, and can use several inadequate instruments, none of which suffices of itself for the operation of the mover; nevertheless one and the same craftsman does not at once use several instruments that are moved adequately, each of which namely suffices of itself for the action of the mover; as is evident from the arts and from the operations of nature to one who considers them attentively. But the body of each man is an adequate instrument of the intellect: because he exercises every operation of his sufficiently through one human body. Therefore one intellect could not use several bodies and several men at once. Since, then, several men are moved by intellect at once—because several men walk at once from an intellective apprehension joined to imagination, for the practical intellect is a mover in men, as is said in Book III of the Soul ⁴; and likewise several men are moved at once toward the intellection of one and the same thing, and toward the works of the sensitive part, which obey the intellect and serve it: it follows that there are several intellects for several men, and not one in number for all.

To the second it is said that from the fact that one mover and one craftsman does not use the instruments of another art, Saint Thomas wishes to conclude that a craftsman who is one in number likewise does not use several instruments of the same species at once: for in both cases the reason is the same. For just as an instrument belonging to another art would be superfluous to this craftsman, so too, if he took several instruments each of which was sufficient in itself, one of them would have to be superfluous. And thus the argument proceeds, and the inference is very well proved.

4. Note, however, that St. Thomas took this argument from Averroes himself, in the third book On the Soul, commentary 5 ⁵, where he says that if there are any animate beings whose first perfection is a substance separate from their subjects, as is thought to be the case with the celestial bodies, it is impossible that more than one individual of one species be found among them. He proves this because their esse would be superfluous: just as it is superfluous for there to be more than one ship in number for one sailor at the same hour; and likewise for there to be more than one instrument of the same species for one craftsman. And he confirms this from what was said in Book I of On the Heavens, where it is said that if there were another world, there would be another celestial body, and it would have a mover numerically distinct from the mover of this body: for it is impossible that one and the same mover in number be the mover of two bodies diverse in number.

III. Third. The soul of a man cannot enter into any body other than a human body, as is held from the Philosopher in I On the Soul, against the ancients, text 53. Therefore the soul of this man cannot enter into any body other than the body of this man. But the soul of this man is that by which this man understands, since the soul is that by which man understands, I On the Soul, text 64. Therefore there is not one intellect of this man and of that man. — The first consequence is proved: because the proportion of the soul of a man to the body of a man is the same as the proportion of the soul of this man to the body of this man.

Note that, since the intellect is that by which we understand most proximately, as the elicitive principle of intellection, if it is posited that man understands by means of the soul, it must be either that the soul is the intellect, or that it has the intellect as its power and potency. On this account St. Thomas concluded, from the fact that the soul by which this man understands cannot be the soul of another man, that the intellect of this man cannot be the intellect of another man.

IV. Fourth ⁶ The form of this man is the intellectual soul. Therefore it is impossible for diverse men to have one intellectual soul. Therefore, etc. — The consequence is proved: because it is impossible for diverse individuals of man to have one form, since each thing, just as it has esse from its form, so it has unity from the unity of the form.

If it is said that the sensitive soul of this man is other than the sensitive soul of that man, and that this suffices for the diversity of men, even though there is one intellect: this cannot stand. For it would follow that those who are posited as two men will not be two men, but only two animals. Which is impossible. — The consequence is proved. Because this individual is a man through the possible intellect, or through the intellective soul. Therefore, if it has a sensitive soul other than that one, but not another intellect, although they are two animals, they will nevertheless be one man. The antecedent is proved. Because a man is a man through that by which he understands, since understanding is the proper operation of man, as is said in I Ethics: for the proper operation follows upon and demonstrates the species of a thing. Now that by which man understands, or the soul, is the intellect. VI. Concerning that proposition, the phantasm is not a first but a second perfection ⁷, there is doubt. Because a second perfection is an operation. But a phantasm is not an operation: since it is a likeness of the individual, as is said in the Prima, q. 85, a. 1, ad 3. Therefore it is not a second perfection.

It can be answered in two ways. First, that by "second perfection" there is not understood here the operation, but an accidental perfection. For it is not from this that substance receives its species, but from its substantial act. And therefore, since a phantasm is an accidental perfection, man cannot receive his species from it.

Secondly, it is answered, and better, that second perfection can be said to be not only the operation itself, but also the term of the operation, thus: for the operation together with its term is a second perfection of the agent. Now the phantasm is the term of man's operation, because it is caused by sense according to act ⁸. Therefore it pertains to man's second perfection, but not to his first. And on this account, it cannot give species to man.

VII. Concerning that proposition, Phantasms which are understood in potency are diverse ⁹ (which seems to be understood of phantasms existing in one man: otherwise it would not be to the point), it must be noted that it can be understood in two ways: namely, either of phantasms that represent individuals of different species, as the phantasms of this man and this horse; or of phantasms of individuals of the same species, as the phantasm of Socrates and of Plato. In both ways it is true that the phantasms which are in the organ of phantasy, which as such are not understood except in potency, are diverse at once in one man.

Of the first, there is no doubt that they are diverse in one man. — Of the second, it is clear from what is said in Prima, q. 76, a. 2, where it is said that in one man there can be diverse phantasms of a stone: which seems to be understood not only successively, but also simultaneously. For there is nothing unfitting in the phantasms of two individuals of the same species being simultaneously in the organ of phantasy: although accidents differing only in number cannot be in the same subject. For these are of the same species insofar as they materially represent individuals of the same species; formally, however, they are of diverse species. For a phantasm representing the property of this individual can be of another species from a phantasm representing the individual properties of another individual; insofar as the phantasm of this stone can represent this stone under the figure of a triangle or under blackness, while the phantasm of another stone can represent that stone under a quadrangular figure or under whiteness. And thus, although they materially represent the same thing according to species, formally nevertheless they represent under diverse species. And thus they themselves are formally of diverse species. — Moreover, even if they were formally of the same species, they could still be simultaneously in the organ of phantasy according to diverse parts of the organ; or because they would be received in diverse spirits serving the operation of phantasy.

2. I do not, however, approve of that reply which says that phantasms of this kind are of the same species in representing, but not in being. For such likenesses receive their species from nowhere else than from the object, just as intelligible species do. And therefore, if they represent the same thing formally according to species, they are formally the same according to species; if they represent things diverse according to species, they themselves are also diverse according to species; although materially and subjectively and extrinsically they may be named otherwise. For the phantasms of a stone in a man and in a horse, although formally and considered in themselves they are of the same species, may nevertheless be said materially to be of different species, because they are in subjects first that are of different species. And things that are formally of different species may be said materially to be of the same species, insofar as they are in the same subject according to species, as is the case with the phantasm of a stone and the phantasm of a horse in a man. But this is said no differently than if we were to say that the whiteness of a swan and the whiteness of snow are of different species, or that the blackness of Socrates and the whiteness of Plato are of the same species: which is clearly said not of them taken formally and in themselves, but only materially and by reason of the subject; which is nothing else than saying that the subjects of those qualities are of one species or of different species. From these considerations it follows that, if different phantasms, representing the same thing formally according to species, are posited in the same subject, those phantasms can in no way be said to be diverse according to species: since they both represent an object that is the same according to species, and exist in the same subject according to species and according to number. And thus it is clear that that distinction is no distinction at all, and moreover contains something false.

VIII. Fifth, an argument is directed against the main point ¹⁰. The possible intellect is that by which the soul understands. Therefore, if it is one and the same in number in this man and in that man, then the understanding of each will also be one and the same. But this is impossible, since there cannot be a single operation of distinct individuals. Therefore, etc. — The consequence is proved as follows: because that by which something operates or acts is a principle to which the operation follows not only with respect to its esse but also with respect to its unity and multiplicity; for from one heat there cannot be more than one active heating, although there can be many passive heatings.

2. To this argument it could be said that understanding is multiplied according to the diversity of phantasms.

But this does not remove the reason. Then, because understanding is not a transitive operation, but remains within the agent itself. And thus it cannot be multiplied by phantasms.

Then, because phantasms are related to the possible intellect in a certain way as the active is to the passive—since understanding is a kind of undergoing—and the undergoing of a patient, namely of one patient, is diversified according to the diverse forms or species of the agents, not according to their numerical diversity: this is made clear in heating, where, since motion is numbered according to its terminus ad quem, and a twofold heat of the same species cannot be in the same subject at the same time, there cannot be a twofold being-heated at once in the same subject unless there be another species of heat—as is posited in seed, the heat of fire, of heaven, and of the soul ¹¹. And thus it is not necessary that understanding itself be diversified by phantasms numerically diverse in different men, whereby they understand one and the same thing at the same time.

Then, because the possible intellect understands man insofar as he is man simply, according to the account of the species, and not insofar as he is this man. But this account is one, however much the phantasms of man may be diversified, whether in one or in many. And thus the multiplication of phantasms cannot be the cause of a multiplication of the very act of understanding with respect to one species.

IX. Concerning the proposition assumed for the proof of the principal consequence of the argument ¹², namely that operation follows upon that by which something operates, with respect to multitude and unity, and that from the same heat there is only one heating, although there can be many things being heated, a doubt is raised. For action and passion are one in subject, though they are formally distinct: as is said in III Physics ¹³. Therefore it does not seem possible that one be multiplied without the other being multiplied. If therefore there are several things being heated, there must be several heatings; and if there is one heating, that there be one thing being heated; and universally, if there is one action and one acting, that there be one passion and one being acted upon.

2. For the clarification of this matter, it must be known that, since action, as was determined above ¹⁴ signifies nothing but motion in a straight line, which is in the patient, and a habitude in something by way of difference, which is in the agent; one must speak of the multiplication of action with respect to its material element in the same way as of the multiplication of motion; but with respect to its formal element, in the same way as of the multiplication of relation. Since, then, motion is in the mobile; and the same accident in number cannot be in diverse subjects; and therefore motion is multiplied according to the multiplication of mobiles: it is necessary that, if several mobiles are moved by one mover, there be from that mover several motions received in several mobiles. And thus, since action, taken materially and with respect to what it signifies in a straight line, is nothing other than motion; it is necessary that where one mover moves many mobiles, there be from it several actions taken materially. But since the relation, which is imported by the name of action as its difference, is in the agent, it cannot be multiplied in number at the same time except according to the multiplication of agents: for several accidents differing only in number cannot be in the same adequate subject simultaneously. And therefore, if one mover moves diverse mobiles at once with the same species of motion—which happens when it moves them by the same formal principle—there can be only one action formally, or, which is the same thing, with respect to the habitude imported obliquely.

The proposition of Saint Thomas, therefore, is to be understood of acting and being acted upon formally, that is, with respect to the very relations themselves: not, however, with respect to what is material in the action. For the material element, both of action and of passion, is multiplied when one agent acts by one principle upon many things. But the formal element of action is not multiplied, although the formal element of passion is multiplied on account of the multiplicity of the subject.

From these things it is evident that in an immanent action there is in no way a multiplication according to number, when it proceeds from one formal principle alone: for the material element in it, which is a quality, is not multiplied, since its subject is one; likewise neither is the relation of the agent. And therefore Saint Thomas concludes most excellently that, if there were one intellect of this man and of that man, there would also be one act of understanding of them: namely, with respect to the same object, and at the same time.

X. Concerning the multiplicity of heat in the seed, when Saint Thomas says that in the seed there is the heat of fire, of the heavens, and of the soul ¹⁵, it must be noted that some hold these heats to be distinct in species, while others say they are not of different species.

Although either opinion can be defended in the doctrine of Saint Thomas, it nevertheless seems to me that he inclines toward the view that they are specifically distinct. For it is clear that in this passage he posits them as really and specifically distinct, from the fact that he says there cannot be a double heating in one subject at the same time unless it is another species of heat, and he gives as an example of this exception the heats that are in seed. For if he understood that they are one heat in reality, but are diversified in species according as they are referred to different principles, this would not serve his purpose, whereby he wants to establish that a double heat of one species cannot be simultaneously in the same subject, but that a multiplicity of heats of different species can well be so. For it is evident that he calls several heats of the same species really distinct heats.

Furthermore, in the First Part, q. 118, a. 1, ad 3, from his manner of speaking he gives us to understand that those heats are distinct, where he says that, besides the power of the soul existing in the seed, there is there a certain heat from the power of the heavenly bodies, by whose power also lower agents act unto the species, and that elemental heat is related instrumentally to the power of the soul. For if he intended one heat to be that of the soul and of the heaven, he would have said that the power of the soul existing in the seed acts also by the power of the heaven, and not that in the spirit, besides the power of the soul, there is also a certain heat from the power of the heavenly bodies. And if he had thought the heat of the soul and of the element to be the same, he would not have said that the heat of the element is related instrumentally to the power of the soul; for an instrument is not identical with that whose instrument it is.

Further, in II Sentences, d. 18, q. 2, a. 3, he attributes different roles to these heats. For of the elemental heat he says that it is like an instrument that dissolves and consumes and performs operations of this kind; of the heat that comes from the soul, he says that it is life-giving; but of the heat of the heavens he says that the spirit, in which such heats are found, moves by its power toward a determinate species.

Although someone might gloss these statements by dragging St. Thomas over to his own opinion, nevertheless, considering the Doctor's opinion sincerely, it seems one must say that they are distinct heats: especially since in the passages cited he posits them to be multiple, while nowhere does he say that they are one heat.

Add to this that the Commentator, in chapter 2 of De Substantia Orbis, holds that the heat of the heavens and elemental heat are distinct according to species.

2. But against this determination some Thomists argue ¹⁶, not from the words of Saint Thomas but from elsewhere, in two ways. First, that the heat of the soul and of the element are the same.

Because in II de Anima, text 41¹⁷, against Empedocles, it is held that animal heat is the principle of growth, not elemental heat: that is, as is said there, heat not according to the power of the element, but according to the power of the soul.

Second, that celestial and elemental heat, and universally the heats that are in seed, are one and the same heat. Because the Commentator on Metaphysics XII, commentary 18¹⁸, holds that these heats are distinguished as the heat of fire is from the heat of art. But elemental and artificial heat are not two heats; they are only distinguished, because the latter is regulated by art, while the former acts absolutely. Therefore, etc.

3. To the first of these it is said first that neither in the text of Aristotle nor in the exposition of Averroes or of Saint Thomas is found what is alleged. For Aristotle there makes no mention of animal and elemental heat, but of fire and soul: for he proves that fire is not the principal agent in growth, but is an instrument of the soul.

It is said second that, even if we grant that Aristotle there wills heat to be the cause of growth not by the power of the element but by the power of the soul (which he nevertheless does not say), it still does not follow that these heats are one heat in number. For it is said, as is said in the First Part, where above ¹⁹, that elemental heat is the instrument of animal heat. And on account of this it is said that heat is the principle of growth not by the power of the element but by the power of the soul: not, however, because they are one and the same heat.

To the second it is said that Averroes assimilates celestial heat to the heat of art in this respect, that celestial heat has its own measure for generation from the motion and disposition of the celestial body, as Averroes himself says in the same place, just as the heat of art derives the measure of its operation from the art itself. But elemental heat does not have its measure from the form of fire itself; rather, if it has any measure and limitation, this belongs to it insofar as it is an instrument of the soul. It is not, however, assimilated to celestial heat in this respect, that it is one and the same with elemental heat. — Although perhaps it could also be said that there is in certain works of art an artificial heat which is not elemental heat.

XI. Sixth²⁰. It would follow that the habit of science is one in number in all men. But this is unthinkable. Therefore, etc. — The consequence is proved. An accident, if it is one in species, is not multiplied except according to its subject. Now the possible intellect is the proper subject of the habit of science, because its act is to consider according to science.

2. If it is said that the subject of the habit of science is not the possible intellect but the cogitative power: — against this it is argued, besides the reasons adduced above when the union of the possible intellect with man was being treated, first because the habit of science in us arises from the acts of the possible intellect, and by that same habit we are able to perform those same acts. From similar acts, as is said in Ethics II, similar habits are formed, and similar habits also render acts similar. — Second, because the cogitative power is not cognitive of universal intentions, but only the possible intellect. Science, however, as is said in Posterior Analytics I, concerns the conclusions of demonstrations, which are universal.

It seems, however, that there was a deception in this discovery of the answer, because on account of the differing disposition of the cogitative and imaginative powers, men are found to be more or less ready for the consideration of the sciences. — But this is nothing. Then, because that readiness depends upon those powers as upon remote dispositions, just as it also depends upon the goodness of the sense of touch and the complexion of the body, as is said in II de Anima. But from the habit of science there is present in us the faculty of considering, as from a proximate principle of the act: since the habit must perfect the power by which we understand so that it may act easily whenever it wills; just as other habits thus perfect the powers in which they reside, namely, that one who has those habits can act according to them when he wills. — Then, because the dispositions of these powers are on the side of the object, namely the phantasm, which through their goodness is prepared so as to be made actually intelligible by the agent intellect. But dispositions which are on the side of the objects are not habits; rather, those which are on the side of the powers. This is shown by an example in the case of fortitude.

3. It must be noted, when it is said that on account of the goodness of the cogitative and imaginative power the phantasm is prepared so that it may easily become actually intelligible through the agent intellect, that this can be understood in two ways. In one way, as if, after the phantasm is in the imagination, the imaginative or cogitative power were to act upon it, disposing it to receive some form from the agent intellect by which the phantasm itself would be actually intelligible, whereas previously it was potentially intelligible. And this sense is not what is intended here. For it does not befit the phantasm: since the phantasm is not said to pass from potency to actual intelligibility as if one and the same phantasm were first in passive potency and afterwards made actual; for the phantasm itself never becomes actually intelligible in itself, since it always remains in a material organ; rather, it is said to become actually intelligible insofar as it causes in the intellect the species which is actually intelligible. For before the agent intellect uses the phantasm itself as an instrument, the phantasm is said to be intelligible in potency, insofar as it can in some way cause an actually intelligible species: just as the formative power in the seed is said to be animate in potency, insofar as it is a productive power of something animated; and the house that is in the mind of the craftsman is said to be a house in potency, as the Commentator says, XII Metaphysics, commentary 18. But when it is joined to the agent intellect as an instrument, it becomes actually intelligible, insofar as the intelligible form which lay hidden in its power is brought into act by the power of the agent intellect from the active potency of the phantasm, and has its foundation in the phantasm itself.

Second, the saying of Saint Thomas can be understood in this sense: that a phantasm, insofar as it is received in an organ of imagination and cogitation more perfectly disposed, is so much the more apt to become actually intelligible. And this is the sense intended here, and it is most true. For the more disposed the organ of imagination is, the more apt is the phantasm for its active power, by which it can produce an actually intelligible species in the possible intellect, to be reduced to act by the agent intellect using that phantasm as an instrument; for a form is received in a subject according to the mode of the receiver.

XII. Seventh²¹. There is one possible intellect of all men. Therefore it is eternal, if men have always existed, as they suppose. And much more so the agent intellect, since the agent is nobler than the patient, as Aristotle says in III De Anima, text 19. Therefore the intelligible species have existed from eternity in the possible intellect. Therefore it will receive no species anew. But this is false. Therefore etc. — The first consequence is evident. — The second is proved: because, if the agent is eternal and the recipient eternal, the things received must be eternal. — The falsity of the consequent is proved: because it follows that sense and phantasia will not be necessary for understanding, since sense and phantasia are necessary for understanding for nothing else except that intelligible species are received from them. And thus Plato's opinion will return, that we do not acquire knowledge through the senses, but are aroused by them to recollect things previously known.

2. Concerning this proposition, "If the agent is eternal and the recipient is eternal, the things received must be eternal," it should be noted that it can have two understandings. The first is that it be understood of the agent and the recipient formally: namely, insofar as it is an agent, and insofar as it is a recipient. And then it needs no gloss. For the sense is, if the agent acts from eternity and the recipient receives from eternity, that it is necessary for the things received to be eternal. That this is most true is evident.

The second way is that it be understood of the agent and the recipient materially: that is, of that thing which is the agent, and of that thing which receives. And then it requires three conditions in order to be true. The first is that the agent act necessarily. For if it could act voluntarily and freely, it would not act from eternity, but in time: just as we say that God produced the universe not from eternity, but in time. And thus what was received would not be eternal. — The second is that agent and recipient be duly brought near to one another. For if some fire were posited as produced from eternity, and the combustible material were eternal; and if the fire were in the east, while the combustible were in the west; and afterwards in time they were brought together by some power, so that the fire could act upon the combustible: there would not be an eternal action between them, and thus the form of fire received in the combustible could not be eternal, but temporal. — The third is that impediments be removed, if the agent be one that can be impeded.

Although, in the ways expounded, each sense may be true and either may be adapted to the text, the first nevertheless seems intended: because it accords with what was proposed. For since the possible intellect has never been idle, nor likewise the agent intellect—if they are posited as eternal—it is necessary to say that the one was receiving from eternity, and the other acting from eternity. And thus the proposition assumed seems to be understood not materially but formally.

XIII. To the principal consequence of this argument Averroes responds that, since the intelligible species has as its subject both the possible intellect and the phantasm—just as the visible species has the thing outside the soul and the visual power—it derives from the intellect its eternity, but from the phantasm its newness.

2. But on the contrary it is argued in two ways. First. It is impossible that the action and perfection of the eternal should depend upon the temporal. But phantasms are temporal, and are made anew each day. Therefore it is impossible that the intelligible species, by which the possible intellect is brought into act and operates, should depend upon phantasms.

Second. Nothing receives what it already has: since the receiver must be stripped bare of what is received, according to Aristotle. But intellectual species existed in the possible intellect before my understanding or yours: otherwise earlier men would not have understood. Therefore, and so on.

3. Nor does it avail to say that the species previously received in the intellect have ceased. For the intellect not only receives, but also preserves what it receives. This is evident: first, because, according to Aristotle in III De Anima, it is called the place of species. — Second, because the intellect is a higher power than sense, and consequently more unified. This is clear: because one intellect has judgment concerning the diverse genera of sensible things, which pertain to diverse sensitive powers. And so, since some sensitive powers only receive, as sense (namely exterior sense); while others retain, as imagination; the intellect itself both receives and retains what is received. For, since it would be vain in natural things to say that that to which motion arrives does not remain but immediately ceases to be, when motion must terminate in rest; much less can it be said that what is received in the possible intellect is not preserved.

XIV. This principal argument is confirmed ²². First, because if the possible intellect does not receive any intelligible species anew, on the grounds that it has already received them from the phantasms of those who came before us, it follows that it never receives any species from phantasms at all. And thus the agent intellect is posited in vain by the Philosopher, as making phantasms actually intelligible. — The consequence is evident. Because, by the same reasoning, it receives nothing from the phantasms of anyone whom others preceded, if the world, as they hold, is eternal.

It is confirmed secondly. Because it follows that the intellect does not need phantasms in order to understand. And thus neither shall we need sense and phantasm in order to understand, since we understand through the possible intellect. Which is false, and against the opinion of Aristotle.

2. But if the consequence is denied, on the grounds that, by the same reasoning, it would follow, even if there were several possible intellects in different subjects, that we would not need a phantasm in order to consider those things whose intelligible species are preserved in the intellect, which is contrary to Aristotle, who says that the soul never understands without a phantasm — this objection is not fitting. For the phantasm, before the intelligible species, stands to the possible intellect as a moving object, and the intellect needs it in order to receive from it the intelligible species. But after the species has been received, it needs the phantasm as it were as an instrument, or as the foundation of its species. For, since the possible intellect, that is, the intellective soul, is the form of the body by nature, and operates, as does everything else, according to the mode of its nature, it indeed understands immaterial things, but it views them in something material; that is, it knows universals in a material singular. Hence at that point the intellect stands to the phantasm in the manner of an efficient cause, insofar as, at the command of the intellect, a phantasm fitting to such a species is formed. The consequence, therefore, is understood to concern the need for the phantasm before the reception of the species. For if the possible intellect had always had species, it would never be related to phantasms as a receiver to a moving object.

XV. Concerning that proposition, "The intellect understands immaterial things, but beholds them in something material," a twofold doubt arises. The first is this: from it there follows that our intellect directly understands singulars. For nothing seems to be in the mind that has not been seen. Therefore, if it does not see immaterial things, that is, universals, except in a particular material thing, it follows that, in seeing the universal, it also sees the singular at the same time. And thus the singular would be known directly. Which is manifestly contrary to the doctrine of St. Thomas ²³.

The second reason is that Saint Thomas, in the Prima, q. XII, a. 4, and q. LXXXV, a. 2 ²⁴, says that by the intellect it is connatural to us to know natures which indeed have esse in individual matter, yet not insofar as they are in individual matter, but insofar as they are abstracted from it by the consideration of the intellect. The argument then runs as follows. It knows the universal by abstraction from matter. Therefore it does not look into matter, as is said here.

2. There is also a twofold doubt concerning the argument for the said proposition ²⁵. First, because if the intellect beholds immaterial things in a material thing precisely because it is the form of the body, on the ground that it operates according to the mode of its nature, it will follow that understanding is by means of a material organ, arguing similarly: — Each thing operates according to the mode of its nature. But the intellect, according to its nature, is the form of the body. Therefore it will understand through the body as well.

Second, because one passes from the mode of cognition as it proceeds from the intelligent being to the mode of the object known as it is known. And thus the fallacy of figure of speech is committed.

XVI. For the solution of the first doubt, it must be considered that, since the powers, both sensitive and intellective, are rooted in the essence of the soul, the soul is the first principle not only of understanding but also of sensing. And further, since the intellective part is the higher part of the soul, and the sensitive powers are by nature made to obey the rational part, the intellective part can move the sensitive powers to their operations insofar as this accords with the intellective operation: just as the visual power and the eye are moved to see a whole piece of wood and a whole stone, and the whole of Socrates, and their parts, so that in that singular thing itself the soul may see every whole to be greater than its part. And thus at once the soul knows some singular thing through sense, and the universal through intellect: just as from the fact that through sense it sees someone moving himself, it immediately knows through intellect that he is a living substance, and thus it is said to see life in motion. In this way, therefore, the intellective soul is said to know immaterial things, or universals, in the material and singular thing: not because the intellect simultaneously sees the singular thing and in that singular thing sees the universal nature, as the figure of a man is seen in a mirror; but because, through the phantasm formed at the command of the intellect, the imagination knows the singular thing which that phantasm represents, and at the same time, through the intelligible species shining forth in that phantasm as an exemplar in what is exemplated or imaged, the intellect knows the universal nature. And thus the same intellective soul—which Saint Thomas here calls by the name "intellect," though not the same power—knows the immaterial and universal in the material and singular thing.

That this is the sense of this proposition is evident from St. Thomas, First Part, q. 84, a. 7, where, showing how the intellect needs the phantasm even after the species, he argues as follows. If the act of some power using a bodily organ were not required for the act of the intellect, it would in no way be impeded in its act by an injury to any bodily organ. But we see that this is false. Therefore it is manifest that in order for the intellect to understand in act—not only when acquiring knowledge anew, but also when using knowledge already acquired—the act of the imagination and of the other powers is required. Likewise, at this place he says that, after the species has been received, a phantasm conforming to the intelligible species is formed in the imagination at the command of the intellect, in which the species shines forth as an exemplar in what is exemplified, or in an image. From these things it is clear that he intends that, together with the act of the intellect, there concur the act of the imagination, and thus to behold in the soul the immaterial in a material thing.

2. Hence, to the argument, the consequence is denied. In proof of this it is said that although nothing can be seen in a thing not seen, it does not follow that both must be seen by the same power; it suffices that the same soul see both by different powers: just as it sees life in the motion of what moves itself, seeing the motion with the bodily eye and life with the intellective power.

It must be noted, however, that for the intelligible species to shine forth in the phantasm as an exemplar in an image is for the species itself, by means of the phantasm, to be in some way reduced to the act of perfect cognition on the side of the object represented through it. For just as Hercules is said to shine forth in his image insofar as the image, when seen, leads a man to knowledge of Hercules—because the interior power is aroused to the inspection or imagination of Hercules—so too the species caused in the phantasm at the command of the intellect, according to a certain conformity with the species, is said to shine forth in the phantasm, insofar as through what is represented to the soul by the phantasm, the soul is aroused to actual cognition of that which is represented by the intelligible species. And this happens because of a certain fittingness of the phantasm to the intelligible species: while one and the same nature is represented through both, it is represented particularly through the phantasm but universally through the species.

3. To the second objection it is said that to behold the universal nature in the singular, which is to behold the immaterial in something material, can be understood in two ways. In one way, that the nature is known according to the esse it has in the singular thing, so that the singular esse of that nature is itself known by the intellect. In another way, not that the nature is known according to its singular esse, but because the very nature that is in the singular thing is known in the singular thing, its singularity nevertheless not being considered: just as taste perceives the sweetness of an apple joined to its whiteness, without perceiving the whiteness. In the first way, to know the nature in the singular is not to know it through abstraction from singulars, but as limited by individuating principles; and this belongs to the sensitive power, as is said in the First Part, q. 12, a. 4. In the second way, however, to know it is, by the first operation of the intellect, to apprehend it through abstraction from individuating principles. The proposition of Saint Thomas, therefore, is to be understood in this second way, and not in the first.

Hence the assumed consequence is false. For it holds at once that the universal is known by abstraction from individual matter, and yet is known in such matter: insofar as the soul, through intellect, apprehends the nature of the species in the singular thing, without considering its individual conditions to which it is joined, although through sense it apprehends those conditions in some way.

XVII. As for the other doubt, concerning the meaning of the proposition assumed ²⁶, it must be considered that, since operation is as it were a certain medium between the agent and the object of the operation, proceeding from the agent and terminating at the object, a twofold mode can be understood in it: one according as it proceeds from the agent; another according as it terminates at the object. The first is proportioned to the mode of the agent—not simply with respect to the mode of being of its nature, but with respect to the principle by which it elicits the operation proximately: for if that principle is in a bodily organ, the operation will be performed through a bodily organ; but if it is not in a bodily organ, neither will the operation itself be produced through a bodily organ. — The second mode, however, is proportioned simply to the mode of being of the operating substance—I say "of being" not in a special sense, but in a general one: for according to the condition of the operating substance there must correspond to it an object connatural to it. For something cannot by its operation naturally attain anything of a higher order: just as lower bodies cannot transmute celestial bodies, although the bodily eye can see them—because, as transmutable things, they belong to a higher order and have matter of another kind than the matter of these lower bodies; but as visible things they are not of a higher order, since in the object of sight they have a commonality with lower bodies.

Hence, since the intellectual soul is a form having esse in matter, it cannot by its act of understanding naturally attain anything except those things that have esse in matter, so as to see their essences; although it can be raised in some measure to an imperfect knowledge of the separate substances through consideration of material things. And just as the soul is in matter, so its act of understanding must attain universal natures as they are in matter, according to what was expounded earlier ²⁷

The proposition of Saint Thomas is therefore true in both senses. For each substance acts according to the mode of its nature, both as regards the mode of nature as the elicitive principle of operation, insofar as the operation proceeds from the agent; and as regards the mode of nature simply, insofar as the operation terminates at the object. But although it is true in both ways, Saint Thomas nevertheless takes that proposition here in the second way, namely, as regards the mode of being of the nature simply, and as regards the operation as terminated at the object. Hence the sense of the proposition is that each thing attains by its own operation, as its natural object, that which has a fittingness with the mode of being of the agent itself, and possesses that mode of being: not indeed so that that mode of being be the terminus of the operation, but so that it be a condition of the object without which the operation does not terminate.

2. To the first objection, then, it is said first that the argument is not directed against the point at issue. For Saint Thomas speaks of operation as it terminates in its object, not as it proceeds from the agent, although even in this latter way it has truth in some sense. The objection, however, proceeds from the mode of operation as it proceeds from the agent.

It is said second, speaking of the operation as it proceeds from the agent, that if the objection proceeds against the declared sense of the proposition, the minor is false. For the soul, as the elicitive principle of the operation, is not in matter, insofar namely as it concerns the power by which it produces intellection, since understanding belongs to it as it exceeds the capacity of matter and as it has a power separate from the material organ: although according to its substance taken absolutely it is a form in matter.

To the second, it is clear from what has been said that no fallacy is committed: because in both the antecedent and the consequent the mode of operation is taken as terminating at the object.

XVIII. It is argued principally in the eighth place ²⁸. And first, the argument is adduced; second, in the following chapter, Avicenna's solution is set forth.

It is argued, however, thus. If there is one intellect of all things, it follows that each of us understands all the things that are or have been understood by anyone whatsoever. This is clearly false. Therefore, and so on. — The consequence is proved. Because, given one possible intellect that is eternal, all the intelligible species of those things that are or have been known by any men whatsoever must already be received in it. But each of us understands by means of the possible intellect; indeed, our understanding is the understanding of the possible intellect.

2. If it is said, as the Commentator says, that this does not follow: because the phantasms are not the same in all, nor disposed in the same way; and we understand through the possible intellect only insofar as it is joined to us through our phantasms; for, even if the possible intellect were not one, we would not understand those things whose species are in the intellect unless phantasms disposed for this were present — it is argued against this. Because, if the species of all the sciences are in the possible intellect, the necessity of phantasms for the possible intellect is like that of one who has a science for considering according to that science, which he could not do even without phantasms. But the intellect made actual by a species can act through itself, as is said in III De Anima and VIII Phys., text 32: and it is not impeded.