De unitate intellectus contra Averroistas

CHAPTER I

[1] All men by nature desire to know the truth; they also have a natural desire to avoid error and to refute it when the opportunity arises. Since we have been given an intellect in order to know truth and avoid error, it seems singularly inappropriate to be mistaken about it. For a long time now there has been widespread an error concerning intellect which originates in the writings of Averroes. He seeks to maintain that what Aristotle calls the possible, but he infelicitously calls the material, intellect is a substance which, existing separately from the body, is in no way united to it as its form, and furthermore that this possible intellect is one for all men. We have already written much in refutation of this, but because those mistaken on this matter continue impudently to oppose the truth, it is our intention once more to write against this error and in such a way that it is decisively refuted.

[2] There is no need now to show that the foregoing position is erroneous because repugnant to Christian faith: a moment’s reflection makes this clear to anyone. Take away from men diversity of intellect, which alone among the soul’s parts seems incorruptible and immortal, and it follows that nothing of the souls of men would remain after death except a unique intellectual substance, with the result that reward and punishment and their difference disappear. We intend to show that the foregoing position is opposed to the principles of philosophy every bit as much as it is to the teaching of faith. And, Latin writers on this matter not being to the taste of some, who tell us they prefer to follow the words of the Peripatetics, though of them they have seen only the works of Aristotle, the founder of the school, we will first show the foregoing position to be in every way repugnant to his words and judgments.

[3] Let us then take up the first definition of soul Aristotle gives in Book Two of On the Soul (412b5): “the first act of a physically organized body.” And lest some should say this definition does not cover every soul, because of the earlier conditional remark, “If, then, we have to give a general formula applicable to all kinds of soul,” (412b4), which they take to mean that it cannot be done, the words which follow should be taken into account. For he writes, “We have now given a general answer to the question, What is soul? It is substance in the sense which corresponds to the account of a thing.” (412a8-12), that is, the substantial form of a physically organized body.

[4] The sequel answers those who might say that the intellective part is excluded from the range of this definition. “From this it is clear that the soul is inseparable from its, or at any rate that certain parts of it are (if it has parts)—for the actuality of some of them is the actuality of the parts themselves,”(413a4-7), which can only be understood of those which belong to the intellective part, namely intellect and will. From this it is clear that some parts of the soul he has defined as being the act of the body are acts of some parts of the body, whereas others are not the acts of any body. It is one thing for the soul to be the act of body and another for some part of it to be the act of body, as will be argued below. In this same chapter he shows the soul to be the act of body because some of its parts are acts of body: “We must apply what has been said [of the whole] to the parts.”(412b17)

[5] From the sequel it is even clearer that the intellect is covered by this general definition. The fact that the body no longer actually lives when soul is separated from it is taken to be sufficient proof that soul is the act of body. However, because something could be said to be in act thanks to the presence of something other than form, of a mover, say, as the combustible actually burns when fire is present, and the moveable actually moves when the mover is present, one might wonder whether the body actually lives thanks to the presence of soul in the same way that the mobile moves at the presence of the mover, rather than as matter is in act thanks to the presence of form. The doubt can feed on the fact that Plato said soul is united to body not as form but rather as mover and director. This is clear from Plotinus and Gregory of Nyssa—whom I mention because they were Greeks not Latins. The Philosopher invites this doubt when, to what has been quoted, he adds “Further, we have no light on the problem whether the soul may not be the actuality of its body in the sense in which the sailor is the actuality of the ship.”(413a8-10).

[6] It was because this doubt remained after what he said that he concludes, “This must suffice as our sketch or outline of the nature of soul” (413a11-13), because he has not yet shown the truth with full clarity.

Therefore, in order to remove this doubt, he proceeds to make manifest that which is more certain both in itself and in definition through what is less certain in itself but more certain for us, that is, through effects of the soul which are its acts. Thus he immediately distinguishes the works of the soul, saying that “what has soul in it differs from what has not in that the former displays life,”(413a21-25) and that there are many levels of life, namely, “intellect, sense, motion and rest according to place,” the motion of nourishing and growth, such that anything in which one of these is found is said to live. Having shown how these [levels] are interrelated, that is, how one of them might be found without the other, he concludes that the soul is the principle of them all both because the soul “is specified (as by its parts) vegetative, sensitive, intellective and motor,” (413b11-13) and because all these happen to be found in one and the same thing, for example, in man.

[7] Plato held that, insofar as these diverse operations pertain to man, there are diverse souls in him. Consequently he [Aristotle] asks “whether each of these is a soul” by itself or a part of soul, and, if they are parts of one soul, whether they differ in definition alone or also in place, that is, by organ. And, he adds, “of some it is not difficult” to see how it is, but there are others which give rise to doubt. (413b13-26) Consequently, he shows(413b16-21) that in this regard things are clear in vegetable and sensible soul because some plants and animals go on living when divided and all the operations that were in the whole appear in each part. When he adds that “We have no evidence as yet about mind and the power to think,” (413b24-25) he makes clear where the question arises. By saying this he doesn’t mean to show that intellect is not soul, as the Commentator and his followers perversely interpret him, for he clearly says this in response to what was said earlier, “but some present a difficulty” (413b16). This should be understood thus: It is not yet clear whether intellect is a soul or a part of soul, and if it is a part of the soul, whether it is separate in place or in definition only.

[8] Although he says it is not yet clear, nonetheless he indicates what at first blush appears to be the case by adding “It seems to be a widely different kind of soul” (413b25-26). This should not be understood as it perversely is by the Commentator and his followers: namely, that the intellect is equivocally called soul or that the foregoing definition cannot be adapted to it. How it ought to be understood is clear from what he adds, “It alone is capable of existence in isolation from all other psychic powers.” (413b26-27) Therefore it is of another kind in the sense that intellect appears to be something perpetual, whereas the other parts of the soul are corruptible. And because the perpetual and corruptible do not seem to characterize the same substance, apparently only this part of the soul, namely intellect, can be separated, not indeed from body, as the Commentator perversely interprets, but from other parts of the soul, lest they characterize the same substance, soul.

[9] That this is how it should be understood is clear from what he adds, “From these remarks it is clear that the other parts of the soul are not separable” (413b27-28), namely from the substance of the soul or by place. When this was asked earlier the question was resolved from what had just been said. That it is not to be understood as separability from body but as the separability of the powers from one another, is clear from what he adds: “that as understood they are distinguishable by definition,” namely from one another,”is clear,” for to sense and to have an opinion are different.”(413b29-30) Thus what is said here is manifestly in response to the question raised earlier when he asked whether one part of the soul is separated from another in understanding alone or in place. Having set aside this question about intellect, concerning which he determines nothing here, he says it is manifest with respect to the other parts of the soul that they are not separable, that is in place, but that they differ as understood.

[10] It being established therefore that the soul is defined by the vegetative, sensitive, intellective and locomotive parts, he intends to show next that, with respect to each of these, the soul is united to body as form, not as a sailor to his boat. And thus what was previously established only in outline is made certain. He proves this through the operations of the soul in this way: It is manifest that that whereby something first operates is the act of the one operating. For example, we are said to know both through the soul and through science, but first of all through science rather than through the soul—we know through the soul only insofar as it has science; similarly we are said to be healed by the body and by health, but first of all by health. Thus it is clear that science is the form of soul and health of the body.

[11] He continues thus: “The soul is that whereby we first live,” referring to the vegetative, “that whereby we sense” referring to the sensitive, “and move” referring to the locomotive, “and understand,” referring to the intellective. He concludes “It follows that the soul must be an account and essence, not matter or a subject.” (414a12-14) Manifestly therefore he applies here what he said above, that the soul is the act of a physical body, not only to the sensitive, vegetative and motive but also to the intellective. It was Aristotle’s judgment, therefore, that that whereby we understand is the form of the physical body. Should someone say that that with which we understand does not here mean the possible intellect but something else, this is clearly excluded by what Aristotle says in Book Three of On the Soul speaking of the possible intellect: “I call intellect that whereby the soul thinks and understands.” (429a23)

[12] But before we turn to what Aristotle says in Book Three of On the Soul, let us linger on what he has said in Book Two so that his teaching on the soul may become apparent by comparing his statements. For, having defined the soul in general, he begins to distinguish its powers, and says that the powers of the soul are “the vegetative, sensitive, appetitive, locomotive, intellective.” (414a31-32) And that the intellective is the intellect is evident from what he afterwards adds in explanation of the division, “In others, the thinking faculty and intellect, as in men.” (414b18) He holds therefore that the intellect is a power of the soul which is the act of body.

[13] And that he calls the intellect a power of this soul and moreover that the definition of soul given above is common to all the aforesaid parts, is clear from his conclusion: “It is now evident that a single definition can be given of soul in the same way that one can be given of figure. For, as in that case there is no figure apart from triangle and those that follow in order, so here there is no soul apart from the forms of soul just enumerated.” (414b19-22) One ought not then seek any soul apart from those mentioned, to which the definition of soul given above is common. Aristotle makes no further mention of intellect in this second book except when he says that “reasoning and intellect” are “ultimately and rarely” (415a7) because they are in fewer things, as the sequel makes clear.

[14] Because there is a great difference between the ways intellect and imagination operate, he adds that “there is another account of speculative intellect” (415a11-12). This inquiry he reserves to the third book. And lest someone suggest, as Averroes perversely does, that Aristotle speaks of another account of speculative intellect because the intellect is “neither soul nor a part of soul”, this is immediately excluded at the beginning of Book Three where he takes up again the treatment of intellect. For he says, “Concerning the part of the soul whereby the soul knows and understands.” (429a10-11) Nor should anyone think that this is said only insofar as the possible intellect is divided against the agent intellect, as some imagine, for the remark occurs before Aristotle proves there is an agent and possible intellect. Hence he here means by intellect that part in general, insofar as it contains both agent and possible. In much the same way, early in the second book, he manifestly distinguished intellect from the other parts of the soul, as has already been pointed out.

[15] Notice the marvelous care and order of Aristotle’s procedure, beginning Book Three with the treatment of the questions concerning intellect left undetermined in the second. There were two. First, whether intellect is separated from other parts of the soul only as understood or in place too, which indeed he left undetermined when he said, “We have no evidence as yet about thought or the power of reflexion.” (413b24-25) First he takes up this question again when he says “Whether this is separable from the others,” namely from the other parts of the soul, “in definition only, or spatially as well.” (429a11-12) `Spatially separable’ here means the same as `separable in place’ above.

[16] Second, he left unanswered the question concerning intellect’s difference from the other parts of the soul when he said later, “Reflective thought presents a different problem.” (415a11-12) And he immediately begins to inquire into this when he says, “We have to inquire what differentiates this part...” (429a12) He intends to express this difference in such a way that it is compatible with both possibilities mentioned, that is, whether or not it is a soul separable in size or place from the other parts, as this way of speaking sufficiently indicates. For he says we ought to consider what the difference is between the intellect and the other parts of the soul, whether it is separable from them in size or place, that is in subject, or not, or only in understanding. Hence it is clear that he does not intend to give as the difference that it is a substance existing separately from the body, for this would not be compatible with the foregoing; rather, he intends to assign a difference according to the mode of operating. Hence he adds, “...and how thinking takes place.” (429a13) Therefore, from what we can learn from the words of Aristotle up to this point, he clearly held that intellect is a part of the soul which is the act of a physical body.

[17] But because from some words following on these the Averroists wish to take Aristotle’s intention to be that the intellect is not the soul which is the act of the body, or a part of such a soul, we must even more carefully consider what he goes on to say. Immediately after he raised the question about the difference between intellect and sense, he asked in what intellect is like sense and how the two differ. Earlier he established two things about sense, namely that sense is in potency to sensible objects and that sense is affected and corrupted by excessive sensible objects. That is what Aristotle has in mind when he says, “If thinking is like perceiving, it must be either a process in which the soul is acted upon by what is capable of being thought” (429a13-15) in such a way that the intellect would be corrupted by something excessively intelligible as sense is by an excessive sensible object, “or a process different from but analogous to that.” That is, understanding is something similar to sensing, but different in this that it is not affected.

[18] He responds to this question immediately, concluding—not from what went before but from what follows, which however is manifested from what went before—that this part of the soul “must be impassible,”(429a15) in order that it not be corrupted like the senses. There is however another way of being acted upon characteristic of understanding according to which it can be said to suffer in a general sense of the term. In this then it is different from the senses. He goes on to show in what it is like the senses, namely, that this part of the soul must be “capable of receiving the form of the object”(429a15-16) and that it be in potency to this kind of form, not actually being it in its own nature; so too earlier it was said of sense that it is potentially, not actually, sensibles. From this he concludes that “Thought must be related to what is thinkable, as sense is to what is sensible.” (429a16-18)

[19] He brought this out to exclude the opinion of Empedocles (see 404b8-405b30) and other ancients who held that the knower is of the nature of the known, as if we knew earth through earth and water through water. Aristotle showed earlier (417a2-9) that this is not true of sense, because the sensitive power is potentially not actually the things it senses, and he says the same here of intellect.

There is however this difference between sense and intellect that sense is not capable of knowing everything (sight is of colors alone, hearing of sounds, and thus with the others), whereas the intellect is capable of knowing all things whatsoever. Ancient philosophers,(see 405b10-17) thinking that the knower must have the nature of the known, said that in order for the soul to know all things it was necessary that the principles of all things be mingled in it. Aristotle, having proved by analogy with sense that intellect is not actually but potentially what it knows, concludes on the contrary that “intellect, because it knows all things, must be unmixed” (429a18); that is, not composed of all things, as Empedocles held.

[20] In support of this he invokes the testimony of Anaxagoras, (429a19) who is not however speaking of the same intellect, but rather of the intellect that moves all things. It was in order that it might command by moving and separating that Anaxagoras said the latter intellect is unmixed. His subsequent proof of this is found in the Greek text: “For the co-presence of what is alien to its nature is a hindrance and a block” (429a20) This can be understood from what is similar in sight, for if there were some intrinsic color of the pupil, this interior color would prevent an outer color from being seen and in that way would prevent the eye from seeing others.

[21] Similarly, if one of the natures of the things the intellect knows—earth or water, hot or cold, or some such thing—were intrinsic to intellect, that intrinsic nature would impede it and in a way obstruct it from knowing others.

Because it knows all things, therefore, he concludes that “it can have no nature of its own, other than that of having a certain capacity” (429a21-22). That is, its own nature is to be potentially those things it understands; but it actually becomes them when it actually knows them, just as sense in act actually becomes the sensible, as was said above in the second book. Intellect before it actually understands, he therefore concludes, “is not actually any real thing” (429a24), which is the opposite of what the ancients said, namely, that it actually is all things.

[22] Because he mentioned what Anaxagoras said in speaking of the intellect which commands all things, lest he be taken to be saying this of that intellect, he uses this manner of speaking: “That in the soul which is called intellect (by intellect I mean that whereby the soul thinks and judges) is before it thinks, not actually any real thing...” (429a22-24) From which two things are clear: first, that he is not speaking here of an intellect which is a separated substance, but of the intellect he earlier called a power and part of the soul whereby the soul understands; second, that he proved from what was said above that the intellect actually has no a nature.

[23] He has not yet proved, however, that it is not a power in the body, as Averroes says, but immediately concludes this from the foregoing: “For this reason it cannot reasonably be regarded as blended with the body.” (429a25) This second conclusion he derives from the first, which he proved above, namely, that intellect does not actually have any of the natures of sensible things. It follows from this that it is not mixed with body, because if it were mixed with body, it would have some corporeal nature. This is what he adds: “If so, it would acquire some quality, e.g. warmth or cold, or even have an organ like the sensitive faculty.” (429a25-27) Sense is proportioned to its organ and is in a way akin to it in nature, hence with the immutation of the organ the operation of sense too is changed. It is thus then that the phrase, “is not mixed with body,” should be understood: intellect does not have an organ as sense does.

[24] And that the soul’s intellect has no organ he manifests through the saying of those who said that “soul is the place of the forms,” (429a27-29) understanding place broadly for any receiver, in the Platonist manner, except that being the place of forms is not true of the whole soul but only of intellect. For the sensitive part does not receive species in itself, but in the organ; whereas the intellective does not receive them in an organ, but in itself. Again it is not the place of the forms as having them actually, but only in potency.

Since he has now shown what belongs to intellect from its similarity with sense, he returns to what he said first, that “the intellective part must be impassible,” (429a15) and thus with wonderful subtlety concludes from its very similarity to sense its dissimilarity, going on to show that “sense and intellect are not impassible in the same way” (429a29-b5) because sense is destroyed by an excessive sensible but intellect is not destroyed by the excessively intelligible. He gives as reason for this what was proved above: “the reason is that while the faculty of sensation is dependent upon the body, thought is separable from it.”

[25] This is the favorite prop of those who want to hold the error that intellect is neither soul nor part of the soul, but a separated substance. But they too quickly forget what Aristotle said only a little earlier: for just as here he says that “the sensitive is not without body and intellect is separate” so above he said that intellect would “acquire some quality, e.g. warmth or cold, or even have an organ like the senstivie faculty.” (429a25-26) This is the reason, therefore, that he here says that the sensitive is not without body but the intellect is separate: because sense has an organ but intellect does not. Quite obviously, therefore, and without any doubt so far as the text of Aristotle is concerned, it is clear that his view is that possible intellect belongs to the soul which is the act of body, such that the soul’s intellect has no bodily organ as the other powers of the soul certainly have.

[27] It is not difficult to understand how the soul can be the form of a body yet some power of the soul not be a power of body if one takes into account other things as well. For in many things we see that a form is indeed the act of a body of mixed elements and yet has a power which is not the power of any element, but belongs to that form because of a higher principle, namely a celestial body, e.g. the magnet has the power to attract iron and jasper of coagulating blood. And presently we shall see that insofar as forms are nobler they have powers which more and more surpass matter. Hence the ultimate form, the human soul, has a power, namely intellect, which wholly surpasses corporeal matter. Thus the intellect is separate because it isn’t a power in the body but in the soul, and soul is the act of the body.

[28] Nor do we say that the soul, in which the intellect is, so exceeds corporeal matter that it does not exist in the body, but rather that intellect, which Aristotle calls a power of the soul, is not the act of the body. For the soul is not the act of body through the mediation of its powers but is through itself (per se) the act of body, giving to body its specific existence. Some of its powers are acts of certain parts of body, perfecting them for definite operations, but the power which is intellect is not the act of any body, because its operation does not take place by means of a bodily organ.

[29] And lest it seem to anyone that we give this as our own reading, not Aristotle’s meaning, the words of Aristotle expressly stating this must be cited. For in Book Two of the Physics he asks “to what degree it is necessary to know the species and quiddity”, for it is not the natural philosopher’s task to consider every form. And he solves this, adding, “to the degree that the doctor must know sinew and the smith bronze,” that is, up to a point. And up to what point he shows, adding, “until he understands the cause of each,” as if to say, the doctor considers the nerve insofar as it pertains to health, and so too the artisan bronze for the sake of the artifact. And because the natural philosopher considers form insofar as it is in matter, for such is the form of mobile body, so too it should be understood that the naturalist considers form insofar as it is in matter.

[30] The term of the physicist’s consideration of form is of forms which are in some way in matter and in another way not in matter, for these forms are on the border of material and separated forms. Hence he adds, “and concerning these,” namely, those forms which terminate the natural philosopher’s consideration, “which are separable but which do not exist apart from matter...” What these forms are, he goes on to show: “For man is generated by man and by the sun as well.” Man’s form therefore is in matter and separate: in matter indeed insofar as it gives existence to body, for thus it is the term of generation, separate however because of the power which is proper to man, namely intellect. Therefore, It is not impossible for a form to be in matter yet its power be separate, as was shown concerning intellect.

[31] There is yet another way in which they go about showing that Aristotle taught that the intellect is not a soul nor a part of the soul united to body as its form. For Aristotle says in several places that the intellect is perpetual and incorruptible, as is clear in Book Two of the On the Soul (413b26-27), where he says, “...differing as what is eternal from what is perishable; it alone is capable of being separated.” And in Book One where he says that intellect seems to be a substance “incapable of being destroyed” (408b17-18). And in Book Three, he says, “This alone is truly separate and it alone is immortal and perpetual,”(430a22-23) although some do not understand this last to be about the possible intellect, but about the agent intellect. From all these texts it is clear that Aristotle means that intellect is something incorruptible.

[32] However, it seems that nothing incorruptible could be the form of a corruptible body. It is not accidental to form but belongs to it per se that it be in matter, otherwise what comes to be from matter and form would be accidentally one; but nothing can exist without that which belongs to it as such; therefore the form of body cannot be without body. If then the body is corruptible, it follows that the form of body is corruptible. Moreover, forms separate from matter and forms that exist in matter are not of the same kind, as is proved in Book Seven of the Metaphysics. Much less can numerically one form be now in body and now apart from body. With the destruction of the body, therefore, either the form of body is destroyed or it passes to another body. If then intellect is the form of body, it seems necessarily to follow that intellect is corruptible.

[33] It should be known that this argument convinces many: thus Gregory of Nyssa, making the reverse point, understood Aristotle to teach that the soul is corruptible because he made the soul a form. Some maintain because of this that soul passes from body to body. Others held that soul has a certain incorruptible body from which it is never separate. It must be shown, therefore, from Aristotle’s words, that he held that the intellective soul is form and nonetheless held it to be incorruptible.

[34] In Book Eleven of the Metaphysics, after he had shown that forms do not exist before their matters, because “when man is healed then health exists, and the shape of the bronze sphere at the same time as the bronze sphere,” he then asks whether any form remains after matter. In Boethius’s translation, “It should be considered whether anything remains afterward” namely, after matter,”for nothing stands in the way of this in some things, as if the soul were of this kind, not all but intellect, or perhaps it is impossible for them all.” What he clearly says, therefore, is that nothing prevents the soul, which is a form, from remaining after the body thanks to its intellective part although it did not exist prior to body. For when he said absolutely that moving causes are prior but not formal causes, he did not ask whether any form were prior to matter, and he says that nothing prevents this in the case of the form which is soul with respect to its intellective part.

[35] When then, in accordance with the foregoing words of Aristotle, this form which is the soul remains after the body, not the whole but intellect, we must yet ask why the soul remains after the body with respect to its intellective part rather than its other parts, and why other forms don’t remain after their matters. The reason is to be found in the text of Aristotle. He says “This alone is truly separate and this alone immortal and perpetual.”(430a22-23) Thus the reason he gives that it alone seems to be immortal and perpetual is that it alone is separate.

[36] But a question arises as to what he is here speaking of, for some say he means possible intellect and others that he means the agent intellect. But both of these are seen to be false when Aristotle’s words are carefully considered, for Aristotle says both are separate. That it is the whole intellective part which is said to be separate because it has no organ is clear from the words of Aristotle.

[37] In the beginning of On the Soul, Aristotle said that “If there is any way of acting or being acted upon proper to soul, soul will be capable of separate existence.” (403a10-12) The reason for the consequence is this: since anything acts according to the kind of being it is, activity will belong to anything in the same way in which it exists. Forms therefore which have no activity without the participation of their matter, do not themselves operate, but the composite acts through the form. Hence forms of this kind do not themselves exist, but something exists because of them. Heat does not warm, but rather the hot thing; so too heat does not exist properly speaking, but the thing is warm thanks to heat. Because of this Aristotle says in Book Eleven of the Metaphysics that one does not truly say of accidents that they are beings but that they are of beings.

[38] The same reasoning applies to substantial forms having no operation in which matter does not take part, except that such forms are principles of being. Therefore a form which has an activity thanks to one of its powers or faculties in which its matter does not participate has existence of itself. It does not exist simply because its composite does, as is the case with other forms, but rather the composite exists thanks to it. Therefore, the composite being destroyed, a form which exists thanks to the existence of the composite is destroyed, whereas a form through whose existence the composite exists, not vice versa, need not be destroyed when the composite is destroyed.

[39] Against this might be objected what Aristotle says in Book One of On the Soul,”Thinking, loving, and hating are affections not of thought, but of that which has thought, so far as it has it. That is why, when this vehicle decays, memory and love cease; they were activities not of thought, but of the composite which has perished.” (408b25-29) The answer is clear from Themistius who, in explaining this text, says that Aristotle “now is more in the mode of the doubter than the teacher.” For he has not yet destroyed the opinion of those saying that intellect and sense do not differ.

[40] Hence in that whole chapter he speaks of intellect in the same way he does of sense. This is especially evident where he proves the intellect to be incorruptible using the example of sense, which is not corrupted by age. Hence throughout he speaks conditionally and problematically as one inquiring, always conflating intellect and sense. This is chiefly apparent from this that, in the beginning of the solution, he says “We may admit to the full that being pained or please, or thinking, are movements, etc.” (408b5-6) Were anyone adamantly to insist that Aristotle speaks decisively here, another response remains. Understanding is said to be the act of the composite, not essentially but accidentally, insofar as its object, the phantasm, is in a bodily organ and not because this activity is exercised through a bodily organ.

[41] A further question might be asked: If intellect does not understand without the phantasm, how can the soul have an intellectual operation after it is separated from body? The questioner ought to know that it is not the natural philosopher’s task to solve this question. That is why Aristotle, speaking of soul in Book Two of the Physics, writes, “It is the business of First Philosophy to resolve how this is separable and what it is..” For it should be seen that the soul when separated has a different way of understanding than it does when conjoined, a way similar to that of separate substances. Hence it is not surprising that Aristotle should say, in Book Three of On the Soul, “Whether it is possible for it while not existing separate from spatial conditions to think anything that is separate, or not, we must consider later.” (431b17-19) This suggests that it can understand something in a separated state that it cannot when unseparated.

[42] What is especially to be noticed in these words is that, while he said earlier that both intellects, namely the possible and agent, are separate, here he says intellect is not separate. For the separate is such insofar as it is not the act of an organ and the non-separate that which is a part or power of the soul which is the act of body, as has been said. Aristotle’s resolution of such questions can be more certainly gathered from what he wrote of separate substances at the beginning of Book Twelve of the Metaphysics, ten books of which I have seen though they are not yet translated into our language.

[43] Given this, therefore, it is clear that there are no necessary arguments for the opposed position. For it is essential to the soul that it be united to body and this is accidentally impeded, not on its part, but on the part of the body which corrupts. In the same way it pertains as such to what is light that it be above. “This is the essence of what is light that it be above,” as Aristotle says in Book Eight of the Physics, “but it can come about through some impediment that it is not above.”

The response to the second argument is clear from this. Although there is a specific difference between that whose nature it is to be above and that whose nature it is not to be above, yet the thing whose nature it is to be above, although it sometimes is and sometimes is not, due to an impediment, is specifically and numerically the same nature. In much the same way, a form whose nature it is to be united to body is specifically different from one whose nature it is not to be united to body, yet a form specifically and numerically the same can be such that its nature is to be united to body although sometimes it actually is and sometimes it is not because of an impediment.

[44] They seek yet another basis for this error in what Aristotle says in the book On the generation of Animals, namely, “intellect comes only from without and it alone is divine.” But no form which is the act of matter comes to it from without, but is educed from the potency of matter. Therefore the intellect is not the form of body.

They object too that every form of a mixed body is caused by the elements; hence if the intellect were the form of the human body, it would not be caused by something else, but would be caused by the elements.

They further object on this score that it would follow that the vegetative and sensitive too would be from something else, which is contrary to Aristotle. This would be especially true when there is a soul one in substance whose powers are vegetative, sensitive and intellective. But, according to Aristotle, the intellective is from without.

[45] The solution of these difficulties readily appears from the foregoing, for when it is said that every form is educed from the potency of matter, it seems that what this means ought to be understood. For if this is only matter’s first existing in potency to the form, nothing prevents our saying that corporeal matter first exists in potency to the intellective soul. Hence Aristotle says in the book On the Generation of Animals, “For at first all such embryos seem to live the life of a plant. And it is clear that we must be guided by this in speaking of the active and sensitive and rational soul. For all three kinds of soul must be possessed potentially before they are possessed actually.”

[46] Because potency is a correlative of act, a thing must be in potency in the same respect that being actual belongs to it. It has already been shown that those forms which have no activities that do not involve matter are such that composites exist through them and they themselves as it were coexist with composites rather than exist themselves. Hence just as their whole existence is in concretion with matter, so they are said to be totally educed from the potency of matter. The intellective soul, however, since it has an operation without body, does not exist solely in concretion with matter, hence it cannot be said to be educed from matter, but it is rather from an extrinsic principle. And this is obvious from Aristotle’s words: “It remains, then, for the reason alone so to enter and alone to be divine,” and he gives the explanation when he adds, “for no bodily activity has any connexion with its activity.”

[47] I wonder whence comes this second objection, namely, that if the intellective soul were the form of a mixed body it would be caused by the mingling of the elements. No soul is caused by the mingling of elements. Right after the words just quoted we read: “Now it is true that the faculty of all kinds of soul seems to have a connexion with a matter different from and more divine than the so-called elements; but as one soul differs from another in honor and utility, so differs also the nature of the corresponding matter. All have in their semen that which causes it to be productive; I mean what is called a vital heat. This is not fire nor any such force, but it is the breath included in the semen and the foam-like, and the natural principle in the breath, being analogous to the element of the stars.” Therefore not even the vegetable soul, let alone intellect, is produced from the mingling of elements.

[48] The third objection, that it would follow that the sensitive and vegetative too would be from an extrinsic principle, is not relevant. For it is already evident from the words of Aristotle that he leaves indeterminate whether intellect differs from the other parts of the soul in subject and place, as Plato said, or by understanding alone. Even if it were given that they are the same in subject, as is truer, still nothing absurd would follow. For Aristotle says in Book Two of On the Soul, “The cases of figure and soul are exactly parallel; for the particulars subsumed under the common name in both cases—figures and living things—constitute a series, each successive term of which potentially contains its predecessor, e.g.the square the triangle, the sensory power the self-nutritive.” (414b28-32)

[49] If however the intellective too is in the same subject, which he leaves in doubt, it would similarly have to be said that the vegetative and sensitive are in the intellective as triangle and square are in the pentagon. For the square is indeed a figure specifically different from the triangle, but not from the triangle potentially in it, no more than four is from the three which is its part, but only from the three existing apart. And if it should happen that different shapes are produced by different agents, the triangle considered as apart and differing from the square would have a different cause from the square, just as it has another species, but the triangle which is in the square has the same producing cause. Similarly the vegetative existing apart from the sensitive is another species of soul and has a different productive cause, but there is the same productive cause of the sensitive and of the vegetative within the sensitive. If then it is said of the vegetative and sensitive which are in the intellective that they are from the extrinsic cause which produces the intellective, nothing unacceptable follows. For there is nothing absurd about the effect of a higher agent having the power that the effect of a lesser agent has, even more so. Hence the intellective soul, although it is from an external agent, nonetheless has the powers had by the vegetative and sensitive souls which are produced by inferior agents.