Commentaria in Summam contra Gentiles, Liber II

After Saint Thomas determined the duration of the soul after it is united to the body, he consequently determines its duration with respect to its production ¹. Concerning this, however, he does three things: first, he brings forward arguments proving that it has always existed and has not had a beginning of its duration; second, he shows that it did not exist before the body ²; third, in the following chapter, he resolves the arguments to the contrary.

I. As to the first, he sets out four reasons why those who posited human souls as immortal in their multiplicity, like the Platonists, said that they existed from eternity, and were united to bodies by a certain vicissitude and released from them. This the Manichaeans also followed. — But those who held them immortal according to something one, said that that one thing was from eternity: whether it be the agent intellect, as Alexander held; or the possible intellect, as Averroes wished, and certain words of Aristotle seem to sound this way, when he says it is perpetual. — Some, however, like Origen, held that they were created before the visible world, and yet are bound anew to bodies: but not that they are eternal.

The first argument is that what will never cease to be never began to be. But the human soul will never cease to be.

Second, because from the incorruptibility of intelligible truth it is shown that the soul is incorruptible. Therefore also from its eternity the eternity of the soul can be proved.

The third is that the universe would lack many principal parts, and many more would be added to it daily. And thus the universe would be imperfect.

Fourth, because it is said in Genesis 1, ³: "On the seventh day God completed the work he had made, and he rested from all the work he had brought to completion."

II. As to the second ⁴, since in the preceding sections it has been shown that there is not one possible or agent intellect of all things, Saint Thomas demonstrates that souls did not exist before bodies, whether from eternity or from the constitution of the world.

And he argues first as follows. The soul is the act of the body. Therefore it does not precede it in duration. — The consequence is proved. Because in one and the same thing, act is posterior to potency in duration.

To this argument it could be said that it certainly proves that the body precedes, in duration, the soul's union with the body; but not that it precedes simply. — But this reply does not satisfy the argument. For in one and the same respect an act is said to be posterior to potency already in some way prepared for the act: because act is the terminus of generation; but the terminus of generation and motion must be posterior in duration both to the motion itself and to the potency that is prepared for act. And thus it is necessary not only that what is posterior be united to matter, but also that it be posterior in being.

It may still be said, perhaps, that these things are true of an act produced by generation or motion, but not of an act not produced by generation but by creation—in the way the followers of Origen and Plato say that souls are produced. — On the contrary: because if a form that comes about through creation is not posterior to potency and ordered to the composite through generation, then the generation of man would not be natural. For although man would generate the body, he would in no way operate toward the esse of that act by which man is man; nor, I say, would he do so principally by producing it itself, nor by disposing the matter in which it might receive its esse, since it already has esse. But this is a most serious absurdity. Therefore, and so on.

III. Second. That which belongs to a thing according to its nature is attributed to it prior to that which befits it beyond its nature. Therefore it befits the soul, prior to being separated from the body, to be united to the body. Therefore etc. — The antecedent is evident. For the former befits a thing per accidens, while the latter befits it per se. — But the consequence is proved as follows. For it is natural for every form to be united to its proper matter; otherwise the composite constituted from them would exist beyond nature.

Third. The soul separated from its whole is imperfect. Therefore it does not befit the natural order that it was first produced separate from the body. — The antecedent is proved: because every part separated from its whole is imperfect. Now the soul is a part of the human species, namely as its form. — The consequence is also proved: because the perfect is prior to the imperfect in the order of natural things.

Note that, although according to the order of generation the imperfect is prior to the perfect, absolutely speaking the perfect is prior to the imperfect, as that which brings it forth to perfection. Hence Saint Thomas says that in the order of natural things the perfect is prior to the imperfect: namely, because the order of nature is absolutely an order of perfection, in which the perfect precedes the imperfect.

IV. Fourthly ⁵. Given that, it is asked whether souls are united to bodies violently or by nature: not violently. First, because such a union would be beyond nature; and thus man, who is composed of both, would be an unnatural being. — Second, because in immaterial substances nothing violent or contrary to nature is found, since they are of a higher order than the heavenly bodies, in which nothing contrary to nature is found.

Not even according to the second position, for two reasons. First, because then they would at some time have been separated by violence. Which is unfitting: both because in spiritual things nothing is violent, and because the violent cannot be prior to that which is according to nature, since it is per accidens. The consequence is proved. Because, if they are united naturally, therefore they desired to be united in their creation. Therefore their not having been united from the beginning was due to some impediment: because natural appetite immediately passes into act unless there is some impediment. But everything impeding the execution of natural appetite inflicts violence. — Second ⁶, because the union of the soul to the body occurs not on account of the soul's appetite, but on account of the body's appetite. For it belongs to matter to desire form, since each thing desires its own perfection: but not conversely.

2. It will perhaps be said, first, that for the soul to be united to the body and to exist separate is natural at different times.

V. But many doubts arise against the fourth argument as immediately adduced.

Concerning the second argument, by which it is argued that the separate soul does not naturally desire to be united to matter, because it is the form of the body, whereas it belongs to matter to desire form and not conversely ⁷: a doubt is raised on two grounds. First, on account of the proposition assumed there, Each thing desires its own perfection. But to be united to the body is a perfection of the soul: since, when separated from the body, it is separated from its whole and imperfect, as is said in the third principal argument ⁸; whereas when united to the body, it is in its whole. Therefore the soul naturally desires to be united to the body, and not only does the body desire to be united to the soul.

Second, because matter is for the sake of form, but not conversely. Therefore matter is required on account of the inclination and nature of form, but not form on account of the inclination of matter.

Confirmed. For Saint Thomas, Prima, q. lxxxix, a. 1, holds that the soul is united to the body for the sake of the betterment of the soul itself.

2. Concerning the arguments against the first response ⁹ there is also doubt. For they seem to conclude even against those who hold that the soul remains after the body, if they are effective against Origen, who held that its union with the body precedes it. For it will be argued in a similar way that it is not natural for the soul to remain after the body. Yet this is false, since the corruption of man is natural, and consequently the separation of the soul from the body. — For it will be argued thus: Those things that are naturally varied with respect to a subject are accidents. If, therefore, to be united to a body and to remain separate from a body are both natural to the soul, then being united to a body will be an accident of the soul. But this is false. Therefore it will not be natural for the soul to remain after the body.

It will follow in like manner ¹⁰, as was argued there in the second reason, that the soul is subject to celestial motion, on account of that alternation of union at the beginning and separation after death.

3. Concerning the second argument against the second reply ¹¹, a doubt is raised. For, just as from the fact that the soul is united to the body voluntarily it follows that the union of soul and body is contingent, because of the concurrence of wills not ordered to one another; so, according to our position, whereby we hold that the soul is created and is at the same time united to the body while being created, the same seems to follow. For God voluntarily creates the soul and voluntarily unites it to the body: and the will of God does not seem to have any necessary order with the will of the man generating, such that when a man wills to generate, God of necessity creates the soul and infuses it into the body generated by the will of the man. Therefore, etc.

VI. To make the first doubt evident, two things must be noted. The first is that those who posited that souls were created before bodies said that they were complete and perfect natures, and that the body came to them only accidentally, as it were a prison for them. For Saint Thomas records this, Potentia, q. iii, a. 10; and De Anima, a. 2, ad 14.

The second point is that the soul's being perfected in its union with the body can be understood in two ways: in one way, that the body itself, taken in itself, is a certain perfection of the united soul; in another way, that from the union of the soul with the body the soul receives a certain perfection which it does not have when separated. And likewise, that the soul is naturally inclined to union with the body can be understood either because it is inclined to the body itself in itself; or because it is inclined to something that follows from union with the body. If it is taken in the first way, then it is not true that the soul is perfected in its union with the body. For the body is related to the soul as matter to form; but matter in itself is not a perfection of form, but on the contrary form is in itself the perfection of matter. Hence neither is the soul inclined to the body itself for its own sake. — But if it is taken in the second way, one thing must be said if we hold that the soul in itself is a complete nature in its species, and another if we hold that it does not in itself have the complement of its species, but is an essential part of human nature. For if it is a complete nature, through union with the body the soul receives no essential or natural perfection: for every natural perfection belongs to it of itself, just as every natural perfection belongs of itself to every specific nature, not through something extrinsic. But if it is an imperfect nature which is part of the human species, then we must say that it receives some perfection from union with the body: for from the fact that it is united to the body, it receives the complement of its species, while it is actually a part of human nature, which does not belong to it when separated from the body.

Hence what Scotus says is false, in Book IV, d. xlv, q. ii ¹²: that the soul is united to the body not for its own good or that of matter, but only for the good of the composite. For a subsistent form, not dependent on matter, would not fittingly be posited as united to matter unless from such a union it obtained some proper good of its own.

2. To the doubt, therefore, it is said that the argument of Saint Thomas is directed against the man. For it supposes, according to the position of the adversaries, that the soul is something complete in species; and, according to the truth, that it is the form of the body, as was proved above. From these it is argued that it does not naturally desire union with the body. For it is argued thus.

If the soul naturally desires to be united to the body, this cannot be because it receives from the union with the body some natural perfection that it naturally desires: for, according to them, the soul is a complete nature in species in itself. It will therefore be because it desires the body itself, as though the body were its perfection. But this cannot be: for a form does not desire matter in itself, but rather the reverse, matter desires form; since form is the perfection of matter, not matter of form. Therefore this union will not come about through the natural desire of the soul, but through the desire of the body desiring the soul as its own perfection.

Hence the first objection proceeds according to our true position, in which we hold that the soul is incomplete in itself, and it concludes truly. But according to the position of those against whom Saint Thomas argues, it does not conclude, because on their view it cannot be maintained that to be united to the body is a perfection of the soul, as was shown.

To the second, it is likewise said that if the form is not held to be complete in species of itself—as we hold in truth—then matter will be for the sake of the form and for the sake of the form's inclination. For matter is such precisely because the form is inclined toward such a species requiring such matter. And thus it is inclined to union with such matter not on account of the matter itself, but so that it may thereby receive the complement of its own species. And thus the argument concludes truly. But if the form is held to be complete in species, as those thinkers held, then it is not true that matter is for the sake of the form; rather, on the contrary, the form is for the sake of matter: namely, because matter requires such a form for its perfection, and the form is united to matter in order to perfect and ennoble it. And thus it follows that the form is not united to matter on account of the natural appetite of the form itself, as the reply said.

For confirmation, it is likewise said that Saint Thomas says this according to the true position on the soul: because we hold that the soul in itself is imperfect, and that through its union with the body it receives the complement of its perfection. But he does not say this according to the opinion of those who hold the soul to be complete in species when separate, on the basis of which supposition it was argued that the soul cannot be united to the body by the natural inclination of the soul itself, as has been shown.

It is said, therefore, in answer to the principal doubt, that Saint Thomas does not say that the soul does not naturally desire union with the body because it is the form of the body, as though it were true that it does not desire such union; on the contrary, as has been brought forward, he holds the opposite. Rather, he argues that this cannot be if it is posited to be such a form as is complete in species of itself: as those against whom he argues wished to maintain.

VII. To clarify the second doubt ¹³, two things must be noted. The first is that the soul is a form giving esse to matter, in which respect it agrees with every form; and it is the form of a corruptible thing, namely man, in which respect it agrees with the other forms of corruptible things; and it is an immaterial and incorruptible form, in which respect it is assimilated to the separate substances. Therefore we can say that something is natural to the soul in three ways: namely, either insofar as it is a form giving esse to matter; or insofar as it is the form of a corruptible thing; or insofar as it is an immaterial and incorruptible form.

The second point is that in the separation of the intellectual soul from the body there are two things: namely, the separation itself from the body, and the soul's persistence after such separation. Therefore we must consider, concerning each of these, how it is natural or unnatural for the soul.

2. If, therefore, the soul is considered insofar as, according to its essence, it is a form absolutely, then to be united to a body as the principle of its esse is natural to it, just as it is to every other form; for it is natural to every form to receive esse in its subject. Hence the Philosopher says, in XII Metaph. ¹⁴, that forms are not prior to matters. But to be separated from a body is against its nature, because it is against the natural inclination of a form to be separated from matter, since from such separation there follows corruption, which is against the natural inclination of the form. For since a form is the principle of being, corruption, which is the way to non-being, is opposed to it, as St. Thomas says in De Malo, q. v, a. 5; whence the Philosopher also says in II de Caelo ¹⁵ that corruption, old age, and every defect are against the nature of this particular thing determined by its form. — But to remain after separation from the body and after the corruption of the body happens to it insofar as it is a form. Hence it is neither natural to it nor against its nature, but accidental: just as being risible is accidental to an animal.

But if it is considered as it is the form of a thing and of a corruptible nature, then in this way too it is natural to it to be united to a body at the beginning of its esse. For the corruptibility of a material nature does not take away the natural inclination of its form insofar as it is a form. Now the natural inclination of a form, as we have said, is toward union with its recipient and with its whole at the beginning of its esse, since there its perfection consists. But to be separated from a body is against its nature: for, however naturally corruptible man may be, corruptibility nevertheless does not belong to him by reason of his form, just as it does not belong to other things, but only by reason of matter, which is composed of contraries. For, since any form of a thing, even a corruptible one, is naturally inclined to union with such matter as is followed by corruptibility, the opposite—namely separation from matter—is against its nature, considering the nature of the form alone: just as, because for a heavy thing to be in a place below is according to its natural inclination, therefore to be removed from the place below is against its nature and violent. Yet because it is the form of a corruptible nature, it does not repugn that it be separated by some agent violently. This does not belong to the form of an incorruptible thing: for that not only is united to matter naturally, but it also repugns that it be separated by any created agent through violence. — But to remain and persevere in its esse after separation, yet not to perish in the very separation, is neither natural to it as such nor against its nature, but happens to it from another condition of itself: for it is not from the inclination or against the inclination of the form of a corruptible thing, as such, to persevere in its esse after its separation from matter.

If it is considered in the third way, namely insofar as it is an immaterial and incorruptible form, then it is likewise natural to it to be united to a body from the beginning of its being, and to be separated from the body is against its nature: because immateriality and incorruptibility do not take away from that which is essentially a form what is natural to a form as form, or repugnant to it. And therefore, since the soul is essentially an incorruptible and immaterial form, incorruptibility does not take away from it what is natural to a form absolutely, or repugnant to it: just as to man, insofar as he is a rational animal, everything that is essential to animal absolutely belongs, and whatever repugns to animal repugns to him, because rationality does not take away the character of animal, although it specifies it; for since sensible esse is essential to animal, while insensible esse repugns to animal, therefore the sensible belongs also to the rational animal, while the insensible repugns to it.

Since, then, it is natural for a form, as form, to be united to matter, and to be separated from it is against its natural inclination; and since the soul, insofar as it is an immaterial and incorruptible form, will naturally be united to the body, while separation from it is against nature—yet for it to persevere in its esse after the corruption of the body is natural to it. For just as, because the soul is essentially a form, what is natural to a form as form belongs to it naturally, so too, because it is essentially incorruptible, there naturally belongs to it what is natural to an incorruptible substance. Now this is natural to the incorruptible insofar as it is incorruptible: that it not be corrupted along with the corruption of that in which it is, but remain in its esse after that thing's corruption. Therefore it is natural to the soul, insofar as it is incorruptible, to persevere in its esse when separated from the body: just as it is natural for a form dependent on matter to fail at the very moment of its separation, insofar as it is a form depending on matter according to esse—even though separation from matter is repugnant to it insofar as it is a form.

But, although it is natural to the soul, supposing that it is separated from the body, to remain separated from the body; speaking absolutely, however, to have an esse separate from the body is against the nature of the soul: because it is natural to it to have esse united to the body. For if something be natural to any form, as following upon its natural appetite, its opposite will be against its nature and inclination: just as, because being in a place below accords with the natural inclination of a heavy body, therefore being outside that place is against its nature. — Nor is what some say true, namely that being separate belongs to the soul, considered according to its proper nature, only as beyond nature (praeter naturam), but not as against nature. For something is said to be beyond one's proper nature when it neither accords with the inclination of nature nor conflicts with its natural inclination: but it is evident that being separate from the body is against the natural inclination of the soul, since it is naturally inclined to have esse united to the body. Therefore it belongs to it not merely beyond nature, but even against nature.

VIII. To the doubt ¹⁶ therefore it is said that the argument of St. Thomas is not against those who hold that the soul remains after the body. For they do not hold that the soul has esse separate from the body naturally, as the response which is impugned there asserts, as though that belonged to it absolutely in accordance with its natural inclination. Rather, they say that this belongs to the soul against nature, just as it belongs to a heavy body against nature to be outside its lower place. — But when it is proved that this belongs to it according to nature because the corruption of man is natural: — the consequence is denied. For the corruption of man is not natural on account of a natural appetite of the soul for separate esse, but on account of the condition of matter, as St. Thomas says in the place cited above ¹⁷, and in I-IIae, q. 85, a. 6.

It must be noted, however, that this argument of Saint Thomas is directed not only against those who hold that the soul has being naturally prior to the body and is afterward naturally united to the body, but also against Avicenna and his followers, who say that both to be united to the body and to be separate from the body belong successively and naturally to the soul. For they say that to be in the body is natural to it at the beginning, while in the end it is natural to it to be separate: just as man's natural way of living is twofold, namely within the womb at the beginning, and then outside the womb. For by this argument of Saint Thomas it is clear that neither mode of esse can be natural to man successively. For he takes as universally true that things which vary naturally with respect to a subject—the subject remaining the same in substance—are accidents. And thus it would follow that the soul is united to the body accidentally. Now from Avicenna's position it follows that to be united to the body and to be separate from it vary naturally with respect to the soul.

IX. But concerning this determination a doubt arises. For Saint Thomas above ¹⁸, where he proves that souls are not united to bodies by violence, assumes this proposition: that in intellectual substances nothing violent is found, nor anything against nature. Therefore, since the intellectual soul is immaterial, it follows that to exist outside the body is not against its nature.

It is confirmed. For Saint Thomas, speaking of this separation in the First Part, q. 89, a. 1, says that to be separated from the body is for the soul beyond the requirement of its nature; but he does not say that it is against nature.

It is confirmed secondly. Because in the same place, in the same way, he attributes to the soul an esse separate from the body, and understanding without a phantasm. But he says that understanding without a phantasm belongs to it beyond nature. And it is evident that it does not belong to itself contrary to nature. Therefore, etc.

2. The response to the principal argument is that Saint Thomas speaks of immaterial substances that are complete in species, as the Platonists used to say souls were immaterial substances. For in such things nothing is against nature. But the soul is not something complete in species; rather it is a part of the human species. Nor is it simply of a higher order than the heavenly bodies, since it is part of material and corruptible nature. And therefore something against nature can be found in it.

To the first confirmation it is said that Saint Thomas sometimes takes "beyond nature" as the same as "against nature." This is evident from three points. First, because here, in the fourth argument, he makes this inference: everything violent is against nature; therefore, if the union of the soul to the body is violent, it is beyond nature. For it is clear that he takes "against nature," which he placed in the antecedent, and "beyond nature," which he placed in the consequent, for the same thing. — Second, because, since he holds here, in the second principal argument, that being separate belongs to the soul beyond nature, below, in book four, chapter LXXIX, in the first natural argument, he says that to be without a body is against nature for the soul. The same is found in Prima, q. cxviii, a. 3. — Third, because in the First Part, where ¹⁹ is cited, he wills that being separated from the body belong to the soul in the same way that being outside its proper place belongs to a light thing beyond nature. Now it is certain that a light thing's being outside its proper place is so far beyond nature that it is against its nature, that is, against its natural inclination. Therefore etc.

To the second confirmation the same reply is made: namely, that "beyond nature" is taken as meaning the same as "against nature." — But when it is said that it is established that understanding without a phantasm does not befit the soul against nature, it is answered that, taking "against nature" as meaning the same as "against the natural inclination of one's own nature," and not as meaning the same as "repugnant to the essence and quiddity," in which way being irrational is against nature for man, to understand without a phantasm is against nature for the soul considered absolutely: because, as St. Thomas says in the same place, the mode of understanding by turning to phantasms is natural to the soul just as is its union with the body; and consequently the opposite mode of understanding will be against the soul's natural inclination, according to what was said above ²⁰. — I say nevertheless that, given the soul's separation from the body, and given that the soul has esse while separated from the body, that mode of understanding is natural to it: just as it was said above ²¹ that, given the soul's separation from the body, it is natural to it not to be corrupted in such separation, but to retain its proper esse even when separated from the body; so that the mode which is against nature for the soul considered absolutely is natural to it as it stands under esse separated from the body. And thus must be understood what St. Thomas says in the First Part, where above ²², ad 3, namely that the cognition of the separate soul through species participated from the influence of the divine light is natural.

3. To the argument against the second argument against the same position, the response is given ²³ that a complete immaterial substance in species, as those held the soul to be an immaterial substance, is not subject to celestial motion: because it entirely exceeds the whole order of time. But a spiritual substance which is part of a species, as we say of the intellectual soul, is subject to motion with respect to its esse, not simply, but insofar as it is variably joined to the body: because, as such, it is not above the whole order of bodies, but pertains in some way to the order of generable and corruptible things, inasmuch as it is part of a generable and corruptible thing. Therefore Saint Thomas's argument concludes against the Platonists and Origenists, but not against those who hold that the soul is a part of man and remains after his death.

X. To the third doubt ²⁴ it is said that this inconvenience does not follow according to our position. For the divine will has a certain order with the will of the human begetter according to the divine disposition. For just as God ordered the lower agents to introduce a form into matter that is disposed and not impeded, so he has disposed himself to create the intellectual soul whenever the matter has been disposed by the human begetter for the reception of such a form. But the will of the human begetter, according to the position of those men, has no order with the will of the separate soul. Therefore, according to their position there follows such an inconvenience, namely, that the union of soul and body be a matter of chance; but not according to our position.

2. Note, however, in the responses to this fourth argument, that, in arguing against certain positions, he says they cannot stand, because he himself considered them simply impossible. But against the third, by pressing an objection, he says it seems unfitting, because it is not impossible for him that souls be from God before bodies are created, though he holds it to be an inconvenience.

XI. Fifth ²⁵ it is argued principally. Either the soul needs the senses, or it does not. If it does need them—as is plainly evident, both because lacking one sense it has no knowledge of the sensibles of that sense, and because no order between sensitive and intellective cognition will be found in man, the contrary of which we experience, since from the senses memories are made, from memories experiences, from which the universal principles of science and art are grasped—therefore it was not instituted without bodily organs. For the senses do not operate without bodily organs. But nature fails no one in what is necessary for the fulfillment of its proper operation.

2. But if it does not need the senses, then, before it was united to the body, it understood by itself the truths of all sciences ²⁶. Therefore, while united to the body, since it is found ignorant, it suffers oblivion of its previously possessed knowledge; and consequently learning is nothing other than remembering. Therefore the union of soul and body imposes an impediment upon the soul's understanding. But all these things are absurdities. Therefore, etc.

The inconvenience and incongruity of all these positions is proved. And first, the incongruity of the last consequent. For, since nature attaches to no thing anything by which its operation would be impeded, there would be no natural union of soul and body, and consequently neither man.

The absurdity of the second consequent is proved: as to the first part, because the soul is united to the body in order that it may arrive at the contemplation of truth. And consequently, through such a union it does not lose the knowledge it has acquired, but is rather united so that it may acquire knowledge. The assumption is evident: because this is the end of man constituted by such a union, since through all his proper, ordered, and right operations he strives to arrive at the contemplation of truth; for the actions of the active virtues are preparations and dispositions toward the contemplative virtues. — As to the second part, because if someone ignorant of the sciences is questioned absolutely about matters pertaining to the sciences, he will answer only from universal principles known naturally by all and in the same way. But if questioned in an ordered way, he will answer truly about the things nearest to the principles, with respect had to the principles; and so on in turn, until he can apply the truth of the first principles to the things about which he is questioned. Therefore it is a sign that through the first principles knowledge is caused in him anew, and not that he recollects what he previously possessed.

3. Note that the foundation of this argument is that, if the one being questioned were, as Plato wished, not acquiring knowledge from first principles but being led back to a memory of what he had previously forgotten, he would answer the truth about conclusions even when questioned in an unordered way, just as he answers the truth about first principles naturally known. For thus the soul, before it was united to the body, had knowledge of conclusions as well as of first principles, according to Plato's position. But now we see that one answers the truth about first principles naturally known, yet not about other things unless questioned in order, according to the syllogistic order, and insofar as one can apply those very principles to the things about which one is questioned. Therefore it is a sign that one does not have natural knowledge of all things as of the first principles; rather, one causes it within oneself by deduction from them, with the questioner arousing it. And so our learning is not merely recollection.

XII. Against the first consequence, however ²⁷, namely that the soul, before it was united to the body, understood by itself the truths of all the sciences, there is a threefold argument.

First. Knowledge, that is, cognition, of conclusions is not the same among all, but only that of the first principles. Therefore cognition of conclusions is not natural to us, but only that of the first principles. Therefore knowledge of conclusions is in us only as acquired from the principles. — The first inference is proved: because things that are natural are the same among all. — The second is also proved: because what is not natural to us is acquired through what is natural, just as we institute artificial things by means of our hands.

2. Second. The intellect has one natural object known per se and naturally, which is being. Therefore it knows naturally only the first principles, while conclusions it knows through them. — The antecedent is proved. As to the first part, because one power has one natural object. As to the second part, however, because all things known by the intellect are comprehended under being. — But the consequence is proved: first by reason, because upon the cognition by which the intellect knows being and those things that are per se attributes of being insofar as it is such is founded the knowledge of the first principles, such as that affirmation and negation are not simultaneously true, and the like; second by the example of color, through which sight knows all visible things.

It must be noted that Saint Thomas does not take the natural object of the intellect and the object proportionate and connatural to it to be the same thing. For, as he himself says elsewhere ²⁸, it is not being, but the quiddity of a material thing, that is such an object of the intellect. But he calls the natural object the adequate object into which the intellect is naturally inclined, as is clear from his own explanation; for he says that such an object is that under which all things known by the intellect are comprehended, just as all colors, which are per se visible, are comprehended under color. Now it is evident that this is the account of an adequate object.

It must be noted, second, that a power having something as its adequate object is borne naturally toward that object alone. But toward the things contained under it, according to their own proper rationes, it is not borne naturally; rather it is borne toward them only insofar as the ratio of the adequate object is preserved in them, and through that adequate object it is borne toward them: just as sight is borne naturally toward color, but is not borne naturally toward whiteness insofar as whiteness is whiteness, only insofar as it is color. On this account, because the intellect naturally knows being alone as its adequate and natural object, and those things that are per se attributes of being insofar as it is such—the knowledge of which grounds the cognition of the first principles—it concludes that only the first principles are known naturally, just as, namely, being alone is known naturally. But conclusions, as such, are not known naturally, but through those first principles themselves: just as sight, through color naturally known, knows all visible things, both common ones and per accidens ones.

3. Third. Knowledge of these very principles is caused in us from sensible things. Therefore neither was knowledge of them present in the soul before the body. Therefore much less knowledge of other things. — The antecedent is proved: because unless we had perceived some whole by sense, we could not understand that a whole is greater than its part, just as one born blind perceives nothing of colors.

It must be noted that what is said here about the principles, namely that their knowledge is caused by sensible things, does not contradict what was said above, where it was stated that our knowledge of them is natural. For, as we declared in the preceding passages ²⁹, the habit of first principles is not said to be natural to us as though it were innate in the soul, but because it is not acquired through argumentation and deduction from it, but only by the natural light of the agent intellect, the senses being presupposed, from which we receive the cognition of terms. Hence such principles are both naturally known to us, and we receive our knowledge of them from sensible things.

XIII. Sixth, it is argued principally ³⁰ If all souls preexisted their bodies, it is necessary that the same soul be united to different bodies in the succession of times. Otherwise one would have to posit an infinite number of souls in act: both according to those who posit the eternity of the world, and according to those who posit that its generation is not eternal yet can nevertheless endure naturally without end. But this is impossible. Therefore, and so on.

The falsity is proved. First, because the numerical diversity of souls (for they are not distinguished specifically, just as men are not) must be taken with respect to their order to different matters, in the way shown above ³¹: for difference according to number belongs to things on account of their material principles. And thus it is necessary that different bodies have different souls united to them.

Then, because the soul is united to the body as its form. Now forms must be proportionate to the bodies they inform, since they are related to one another as act and potency.

Then, because even if it is posited not to be the form of a body, it cannot be denied that it is a mover. But the power of a mover must be proportionate to its movable object. And thus, according to the diversity of bodies moved by the soul, there must be a diversity of souls.

Then, because the same thing would return naturally one in number through generation: whether it is posited, according to Plato, that man is a soul clothed with a body, or whether the soul is posited to be the form of man, and not man himself; for those things are one in number whose form is one, since the unity of a thing follows upon its form, just as does its esse. But this is impossible: because in things that are generated and corrupted, the same substance does not remain, as it remains in things that are moved according to place.

It must be noted, concerning this last statement, that Saint Thomas wishes to assign the reason why the same thing cannot return in number through generation, by contrast with what is found in local motion. For since, when a movable thing ceases to be moved, the substance of the mobile remains, one mover can move the same mobile many times. But in generation and corruption the same substance does not remain, so that the same substance should first be corrupted and afterwards generated, as one mobile is now moved by one motion, now by another; rather, through corruption the substance of the thing ceases to be (esse). Therefore that which was previously corrupted cannot be produced again in number by a new generation. Hence what has ceased to be (esse) through corruption cannot again be produced through generation, as if it remained the same according to substance under both changes.

XIV. But concerning this argument there are several doubts. First, concerning what is said, namely that there would have to be infinitely many souls if the transmigration of souls is not posited, even without positing eternal generation a parte ante, but only a parte post. For this does not seem true. For, given the eternity of the world a parte ante, infinite generations and infinite men have preceded: therefore it is necessary that infinitely many souls have preceded, and thus it is necessary that infinitely many souls exist in act. But with generation posited as eternal a parte post yet finite a parte ante, this does not follow. Because all generations from the first up to that one which was last produced (for there must always be some last generation) are finite. And consequently the souls are never actually infinite in number, although their number can be increased to infinity: just as one who begins counting from unity, though he can proceed to infinity by counting, nevertheless the whole number taken by him will never be infinite.

Second, a doubt is raised concerning the argument by which it is proved, from the proportion of the mover to the thing moved, that one soul cannot be united to several bodies. For the Platonists would say that it is not unfitting for one mover to be united successively to different things moved: just as one man can move different things successively.

Third, concerning the last argument for the same point, doubt is raised when it is said that those things are one in number whose form is one in number. For this does not seem sufficient. Because for the numerical unity of a material nature the unity of form does not suffice, but the unity of matter is also required, since for its esse form alone does not suffice, but matter is also required. — It is confirmed as well: because Saint Thomas, Quodlibet XI, q. 6 ³², and IV Sent., d. 44, q. 1, a. 1, quaestiuncula 1, holds that for the numerical unity of a composite the unity of matter and of form is required. — The same seems to be intended above in this argument, where he said that difference according to number is according to material principles. Therefore, and so on.

XV. To the first doubt it is said that, if souls are successively created, as we hold, and an infinite generation is posited only a parte post, it never follows that there are actually infinite souls, as was argued. But if all souls were created simultaneously, as Origen held—against whom St. Thomas argued—it is necessary to say that they are actually infinite. For there must be simultaneously in act before bodies as many souls as there are possible generations to be produced. Now, naturally producible are infinitely many successive generations, given a generation infinite a parte post. Therefore it is necessary that actually infinite souls preexist. And thus the argument of St. Thomas proceeds.

2. To the second it is said that Saint Thomas speaks of the mover with respect to its own proper and adequate mobile. For thus we say that the soul of Socrates moves the body of Socrates as its proper and adequate mobile, because it cannot, while it is clothed in the body of Socrates (to speak in the Platonic manner), immediately move any other body, but is determined to moving that one. Speaking, therefore, of a mobile in this way, it is necessary that the power of the mover be proportioned to its mobile, namely, that it cannot immediately move another mobile: for if it could immediately move another body, then the body which it moves would no longer be its own proper and adequate mobile. On account of this the philosophers say that one intelligence applied to one orb for the sake of moving it cannot move another orb. — But what is said, that we can successively move diverse things, is not to the point: because none of those mobiles is a proper and adequate mobile to us.

3. To the third, a twofold reply can be given. First, that although for numerical unity in material things the unity of matter is required, nevertheless the unity of form is what is required more principally: because form is that which gives esse. Therefore Saint Thomas said that those things are one in number whose form is one in number. For although from the unity of form alone something is not called one in number simply and in every way, which is how Saint Thomas speaks in the passages cited; it is nevertheless called the same in number in a qualified sense (secundum quid), and with respect to what is principal in such unity. And thus it follows, if the same soul were united to different bodies, that there would return the same thing in number with respect to the principal cause of such unity. Which is impossible in things that are generated and corrupted: for just as by generation the same Socrates cannot return altogether, so neither can he return with respect to the same form in number.

Second, it is answered that by that proposition matter is not excluded from numerical unity but included: since form has no numerical unity except by its ordering to matter. For thus, if through generation the same form returns in number, as the Platonists hold, it must retain an order to the same matter as to the principle of its individuation. And so the same thing will return simply in number. On the other hand it follows that it does not return the same in number: because it is posited that the form does not retain an order to the same matter, but successively informs different matters. Hence from this position contradictory conclusions follow: namely both that the same thing returns simply in number, which is impossible; and that it does not return the same simply in number. Therefore it is altogether impossible.

XVI. Finally, the principal conclusion is confirmed, because the teaching of the Catholic faith accords with this truth: as is clear from the Psalm saying, "Who fashioned singly the hearts of them"; and also from the Book of Ecclesiastical Dogmas: "The souls of men we say," etc.

But concerning what is said last, namely that the conclusion proved in this chapter is in accord with the teaching of the Catholic faith, a doubt arises. For, since Origen held that all human souls and angels are of one species, and that they were created together with the angels, as St. Thomas holds in the First Part, q. 75, a. 7, and in the Quaestio de Anima, art. 7; in the same way it pertains to the faith that all souls were created together before their bodies, and that the angels were created before corporeal creation. But St. Thomas says in the First Part, q. 61, a. 3, of the angels, that this is not to be considered erroneous, especially on account of the teaching of Gregory Nazianzen ³³. Therefore neither is this position of Origen about souls erroneous. Therefore its opposite is not in accord with the teaching of the Catholic faith, as is said here, namely that according to the faith one must hold it thus.

2. The answer is given: and it is said first, that certainly, as is said here, that neither souls nor other immaterial substances were produced before bodies is in accord with the teaching of the Catholic faith, and has been determined by the Church: as is clear in the chapter Firmiter credimus, Extra, De Summa Trinitate et Fide Catholica ³⁴. Nor was Saint Thomas ignorant of this determination of the Church: since he himself interpreted that decretal ³⁵, if the Opuscula attributed to him are genuine.

It is said secondly, from the teaching of St. Thomas, Prima Pars, q. 32, a. 4, and II Sent., d. 12, q. 1, a. 2, that something pertains to the faith in two ways: in one way, directly and per se, as those things that have been principally handed down to us by God to be believed, such as that God is three and one, and that the Son of God became incarnate; in another way, indirectly and as it were per accidens, as those things contained implicitly in these truths, or which can be deduced from them, such as those things contained historically in Sacred Scripture, which we hold by faith to have been promulgated at the dictation of the Holy Spirit. — Likewise, an error in faith can be said to be such in two ways: namely, directly and per se, as what is contrary to the principal articles of faith; and indirectly, as that from which follows something contrary to the faith, just as from holding that Samuel was not the son of Elkanah there follows that divine Scripture is false. In the first way, no one can hold an error as true without the vice of heresy, if pertinacity is present. But to hold as true what is erroneous in the second way can occur without the vice of heresy, before it is considered that something contrary to the faith follows from it. But after it has become manifest from the error itself that something contrary to the faith follows, or after the Church has determined that the opposite must be held according to faith, to hold that error as true is not without the vice of heresy. It is said, therefore, that that souls were not produced before bodies, nor angels either, is consonant with the sentence of faith, not as pertaining directly to the faith, like something principally handed down to us to be believed, but indirectly, as handed down implicitly in the truth of Sacred Scripture. And likewise the opposite is erroneous, not directly, as being contrary to those things proposed to us principally as to be believed, but indirectly, namely as that to which there follows something contrary to the faith according to the determination of the Church; for instance, because from it there follows that Sacred Scripture is false, which says that in the beginning God created heaven and earth³⁶, and consequently created nothing before heaven and earth. Since therefore this is erroneous indirectly, before the opposite was determined by the Church, or before it plainly appeared that this very thing was indirectly erroneous, it could be held as true without the vice of heresy. And thus Gregory Nazianzen, holding this view, was not a heretic, because it had not yet been determined by the Church that the opposite was to be held. But whoever would now hold it pertinaciously would have to be judged a heretic.

When, therefore, it is said here to conform to the teaching of the faith that there were no spiritual substances created before bodies, this is understood of the teaching of the faith not directly pertaining to the faith, but of the teaching handed down to us by the determination of the Church as indirectly pertaining to the faith. — But what is said in the First Part, that the contrary is not to be reckoned erroneous, is understood of the erroneous directly pertaining to the faith. For the sense is that it is not to be reckoned erroneous directly and in itself, but only by the determination of the Church. And therefore Gregory, before such a determination, could hold it as true without detriment to the faith. Now it is clear that these are not opposed: that something pertain indirectly to the teaching of the faith; and that its opposite not be erroneous directly, but only indirectly.

3. That this response accords with the mind of St. Thomas is shown from the Questions on Power, q. III, a. 9. For there, after he had recited the opinion of those who say that the soul of a child is propagated from the soul of the parent, and the opinion of those who say that all souls were produced before bodies, likewise the opinions of those who say that souls are infused into bodies at the very moment they are created, he adds that although these opinions were for some time tolerated, and which of them was truer was held in doubt, as appears from Augustine, X super Gen. ad litt., nevertheless the first two were afterwards condemned by the judgment of the Church, and reasonably; but the third was approved.

4. It may also be answered that the Church determines that the angels were created together with corporeal creation, as indeed necessarily to be held, since it is against the opinion of Origen, who posited that all spiritual substances were produced together before the corporeal creature, but that, these having sinned in various ways, the whole corporeal creation was afterwards produced for the punishment of their demerits; but as against the opinion of other doctors it is to be held only as more probable.