Article 9 — Whether the rational soul is brought into being by creation or by the transmission of seed

The ninth point of inquiry is whether the rational soul is brought into being by creation or by the transmission of seed. (Parallel texts: ST I.90.2; I.118.2; SCG II.86‒89; Compendium theologiae, ch. 93; In II Sent. 18.2.1; 19.1.4; On Truth, q. 27, a. 3, ad 9; On Spiritual Creatures, a. 2, ad 8; Quodlibet IX, q. 5, a. 1; Quodlibet XI, q. 5, ad 1, 4; Quodlibet XII, q. 7, a. 2.)

Obj. 1: And it would seem that it is propagated with the seed. For it is written: all the souls that went with Jacob into Egypt and that came out of his thigh, besides his sons’ wives, sixty-six (Gen 46:26). Now, nothing comes from a father’s thigh except through the transmission of seed. Therefore, the rational soul is transmitted with the seed.

Obj. 2: It may be replied that the part is being given for the whole, namely, the soul for the man.

On the contrary, a man is composed of soul and body. Therefore, if the whole man comes forth from his father’s thigh, it follows (as above) that not the body only but also the soul is transmitted with the seed.

Obj. 3: An accident cannot be transmitted unless its subject be transmitted, since an accident does not pass from one subject to another. Now, the rational soul is the subject of original sin. Therefore, seeing that original sin is transmitted from parent to child, it would seem that the child’s rational soul is transmitted from its parent.

Obj. 4: It may be said that although original sin is in the soul as in its subject, it is in the flesh as in its cause, and consequently is transmitted by the transmission of the flesh.

On the contrary, it is written: by one man sin entered into this world, and by sin death; and so death passed upon all men in whom all have sinned (Rom 5:12). The words in whom are expounded by a gloss as meaning, in which sinner or in which sin. (Augustine, On the Merits and Forgiveness of Sins and on Infant Baptism 1.10 (PL 44:115–16).) Now, all would not have sinned in that sin unless that same sin had been transmitted to all. Therefore, the same sin that was in Adam is transmitted to all men; consequently, so is the soul that was the subject of that sin.

Obj. 5: Every agent produces its like. But every agent acts through the power of its form. Therefore, that which an agent makes is a form. But the begetter is an agent. Therefore, the form of the begetter is produced by the action of the begetter. Since, then, a man begets a man, and the rational soul is the form of a man, it would seem that the rational soul is produced by generation and not by creation.

Obj. 6: According to the Philosopher in Physics 2, an efficient cause falls into the same species in its effect. (Aristotle, Physics 2.7, 198a26.) Now, man takes his species through his rational soul. Therefore, it seems that the rational soul is caused by the begetter in the begotten.

Obj. 7: Children are like their parents because they are begotten by their parents. But they are like their parents not only in dispositions of the body, but also in those of the soul. Therefore, as bodies derive from bodies, so do souls derive from souls.

Obj. 8: Moses says: the soul of all flesh is in the blood (Lev 17:11). Now, blood is transmitted with the seed, especially as the male seed is merely boiled blood. Therefore, the soul is transmitted with the seed.

Obj. 9: Moreover, the embryo, before it is perfected with the rational soul, has a certain action of the soul, for it grows, self-nourishes, and senses. But where there is the soul’s action, there is life. Consequently, it is alive. Now, the soul is the principle of life in a body, so it has a soul. But it cannot be said that it receives yet another soul, because then there would be two souls in one body. Therefore, the very soul that was from the beginning transmitted in the seed is the rational soul.

Obj. 10: Souls differing in species constitute animals of different species. If, then, before the rational soul itself, there was in the seed a soul that was not rational, there was an animal of a different species from man, which consequently could not become a man, since diverse species of animals do not turn into each other.

Obj. 11: You will say that these actions belong to the embryo not through the soul, but by some power of the soul known as the “formative power.”

On the contrary, power is rooted in substance; hence, it occupies a place between substance and activity, according to Dionysius. (Pseudo-Dionysius, The Celestial Hierarchy 11.2 (PG 3:290–92).) Consequently, if the soul’s power is there, its substance is there also.

Obj. 12: The Philosopher says, On Animals 16, that the embryo is alive before it is an animal, and an animal before it is a human being. (Aristotle, On the Generation of Animals 2.3, 736a34–b6.) Now, every animal has a soul. Therefore, it has a soul before it has a rational soul, by which it is a human being.

Obj. 13: According to the Philosopher, a soul is the act of a living body as such. (Aristotle, On the Soul 2.1, 412a21.) Now, if the embryo is alive and exercises life’s activity by means of this formative power, this very power will be its act insofar as it is a living thing. Therefore, it will be a soul.

Obj. 14: According to On the Soul 1, (Aristotle, On the Soul 2.2, 413a31–b1; 2.4, 415a25.) living is present in all living things through the vegetative soul. Now, it is clear that the embryo lives before the infusion of the rational soul, since life’s activities are found in it. Therefore, the vegetative soul is in it before the rational soul.

Obj. 15: In On the Soul 2, the Philosopher disproves the assertion that growth is the effect of fire as principal agent, rather than of the vegetative soul. (Aristotle, On the Soul 2.4, 416a9–18.) Now, the embryo grows before the advent of the rational soul. Therefore, it has a vegetative soul.

Obj. 16: If, before the advent of the rational soul, there is not a vegetative soul but a formative power, this power will not have its own activity at the advent of the soul, since the activity the power exercised in the embryo will subsequently be sufficiently fulfilled in the animal through the soul. Consequently, it would remain superfluous, and this would seem to be incongruous, since nothing is superfluous in nature. (Aristotle, On the Parts of Animals 4.2, 691b5.)

Obj. 17: You will say that this power is destroyed at the advent of the rational soul.

On the contrary, dispositions are not destroyed at the advent of the form; rather, they remain and in a certain way hold on to their form in the matter. Now, this power was a certain disposition for the soul. Therefore, at the advent of the latter, that power is not destroyed.

Obj. 18: By its action, this power conduces to the introduction of the soul. If, then, at the soul’s advent this power is destroyed, it seems to do for its own destruction. This is impossible.

Obj. 19: A man is a human being by his rational soul. Therefore, if the soul does not go into being by generation, it will not be true to say that a man is generated, which is clearly false.

Obj. 20: Further, the human body goes into being by the action of its begetter. If, then, the soul does not go into being by its begetter, there will be two sorts of being in man: one of the body (which the begetter makes), and another of the soul (which he does not make). And consequently, soul and body will not become one being simply, since they differ in being.

Obj. 21: Moreover, it is impossible that the matter be the terminus of action of one agent, and the form the terminus of action of another agent. Otherwise, form and matter would not together make one thing simply, for one thing is made by one action. Now, the action of the nature of the begetter terminates in the body. Therefore, it terminates in the soul also, which is the form of the body.

Obj. 22: Moreover, according to the Philosopher in On Animals 16, principles whose actions are not performed independently of the body are produced together with the body. (Aristotle, On the Generation of Animals 2.3, 736b22–26.) Now, the action of the rational soul is not independent of the body, since understanding would most of all be independent of the body, and this is clearly not the case. For we cannot understand without images, as is said in On the Soul 1 and 3, (Aristotle, On the Soul 1.1, 403a8; 3.7, 431a16; 3.8, 432a73.) and there cannot be images without a body. Therefore, the rational soul is transmitted with the body.

Obj. 23: To this it may be replied that in its understanding, the rational soul requires images for the acquisition of intelligible species, but not after it has acquired them.

On the contrary, after a man has acquired knowledge, his intellect is hindered from acting if the organ of imagination is injured. And this would not be the case if the intellect, after acquiring knowledge, were no longer in need of images. Consequently, it needs them not only in acquiring knowledge but also in using the knowledge it has acquired.

Obj. 24: But you may reply that the impediment to intellectual activity due to an injury to the organ of imagination arises not because the intellect needs images in using the knowledge it has acquired, but from the fact that imagination and intellect are in the one essence of the soul; whence when the imagination is impeded, the intellect is also impeded accidentally.

On the contrary, the conjunction of powers in the one essence of the soul is the reason why, if the act of one power be intense, the act of the other is diminished; for example, when someone is intent on seeing, he is less intent on hearing. It is also the reason why one power acts with greater strength when another ceases its act; whence, the blind are often sharp of hearing. Therefore, this conjunction of powers is not a reason for the action of the intellect being hindered through an impediment to the imagination; in fact, it should rather be strengthened.

Obj. 25: He who gives the work its final complement is the worker’s chief cooperator. Now, if all human souls are created by God and by him they are infused into bodies, he himself gives the final complement to a generation that comes of adultery. Therefore, he cooperates in adultery, which seems absurd.

Obj. 26: According to the Philosopher, a perfect thing is one that can make its like; consequently, the more perfect a thing is, the more is it able to make its like. (Aristotle, Meteorology 4.3, 380a15; On the Soul 2.4, 415a27.) Now, the rational soul is more perfect than the material forms of the elements, which produce other forms like themselves. Therefore, the rational soul has the power by way of generation to produce another rational soul.

Obj. 27: The rational soul is situated between God and corporeal things; therefore, it is asserted, in The Book of Causes, that it is created on the horizon between eternity and time. (The Book of Causes, Proposition 2.) Now, there is generation both in God and in corporeal things. Therefore, the soul, which is situated between them, is also produced by generation.

Obj. 28: The Philosopher says, in On Animals 16, that the spirit that comes forth with the seed of the male is a power of the principle of the soul and is a divine thing. (Aristotle, On the Generation of Animals 2.3, 736b13–29.) Now, such a thing is called the intellect. Therefore, the intellect seems to be transmitted with the seed.

Obj. 29: The Philosopher says, in the same book, that in generation, the female provides the body and the soul is from the male; (Aristotle, On the Generation of Animals 2.3, 737a9–11, 737a23–24; 2.4, 738b22–23.) thus, it seems that the soul exists through the propagation of the seed and not through creation.

On the contrary (1) it is written: every breathing I have made (Isa 57:16), and by “breathing,” we are to understand the soul. Therefore, it seems that the soul is created by God.

Furthermore (2), it is written: he makes the heart of each one of them (Ps 32:15). Therefore, one soul is not engendered by another, but all are created separately by God.

I answer that in times past this question used to be answered in various ways by different people.

Some used to say that the soul of the child is propagated from the soul of the parent, just as its body is from the body of the parent.

Others used to say that all souls were created apart from bodies, but they held that they were all created together without bodies, and afterwards each one was united to an inseminated body—either by its own proper motion of will, according to some, or by God’s command and operation, according to others.

Others used to say that souls are simultaneously created and infused into bodies.

Although formerly these opinions were held, and it was doubtful which of them came nearest to the truth (as may be gathered from Augustine, even in books that he wrote about the origin of the soul), (Augustine, On the Literal Interpretation of Genesis 10.21–22 (PL 34:425–26); On the Soul and Its Origin (PL 44:475–548).) later the first two were condemned by the Church and the third approved. (Pope Vigilius, Canon 1, Against Origen; Council of Braga II, Anathemas Against Heretics 6; Pope Anastasius II, Letter to the Bishops of Gaul.) Hence, we read in Of Church Doctrine: we do not believe in the fiction of Origen that human souls were created at the beginning with the other intellectual natures, nor that they are inseminated together with their bodies by coition, as the Luciferians (with Cyril) and certain Latin writers have presumed to maintain. But we affirm that the body alone is inseminated by sexual coupling, and that after the formation of the body the soul is created and infused. (Gennadius of Marseilles (d. ca. 496 AD), Book of Ecclesiastical Dogmas (De ecclesiasticis dogmatibus) 14 (PL 58:984).)

A careful examination will make it clear that the opinion that this question concerns, that held the rational soul to be transmitted with the seed, was rationally condemned. Three arguments will make this evident for the present.

The first argument is that the rational soul differs from other forms in that to the other forms does not belong an existence in which they themselves subsist, but rather an existence whereby the formed things subsist in them; but the rational soul has being in such a way as to subsist in it. This is made clear by their respective modes of action. For seeing that only that which exists can act, a thing stands to activity or action as it stands to being, so that, since the body must of necessity take part in the action of other forms, but not in the action of the rational soul, which is to understand and will, it follows of necessity that being must be ascribed to the rational soul itself as subsisting, but not to other forms. For this reason the rational soul is the only form that can exist separate from the body.

Hence, it is clear that the rational soul goes forth into being not as other forms do, to which properly speaking coming to be does not belong, but rather are said to come to be by something having been made. But a thing that comes to be, comes to be properly speaking and through itself. Now, what comes to be, comes to be either from matter or from nothing. What comes to be from matter necessarily is a coming to be from matter subject to contrariety, since generation is from contraries, according to the Philosopher. (Aristotle, On the Generation of Animals 1.18, 724b9.) Therefore, since a soul has either no matter at all or at least none that is subject to contrariety, it cannot come to be from something. Therefore, it follows that it comes into being by creation, as made out of nothing. Now, to maintain that the soul comes to be through the generation of the body is to say that it is not subsistent, and consequently, that it is corrupted with the body.

The second argument is that it is impossible for the action of a corporeal power to rise to the point that it can cause a wholly spiritual and incorporeal power, because nothing acts beyond its own species; in fact, the agent must stand higher than its patient, as Augustine asserts. (Augustine, On the Literal Interpretation of Genesis 12.16 (PL 34:466–67).) Now, the begetting of a man is effected by a generative power that has a corporeal organ; moreover, the power that is in the seed does not act except by the mediation of heat, as is said in On Animals 16; (Aristotle, On the Generation of Animals 2.3, 736b35.) therefore, since the rational soul is a wholly spiritual form, neither dependent on the body nor exercising its action in common with the body, it can by no means be propagated through the generation of the body, nor be brought into being by some power that is within the seed.

The third argument is that every form that comes into being by generation or a power of nature is brought forth from the potency of matter, as is proved in Metaphysics 7. (Aristotle, Metaphysics 7.7, 1032a15–17, 1032b17–22.) Now, the rational soul cannot be brought out from the potency of matter. For forms whose activities are without the body cannot be brought out from corporeal matter. It follows, then, that the rational soul is not propagated by the power of the generator. This argument is given by Aristotle. (Aristotle, On the Generation of Animals 2.3, 736b22–29.)

Reply Obj. 1: In the passage quoted, the part stands for the whole, namely, the soul for the whole man, by the figure of synecdoche; and this because the soul is the chief part of man, and a whole seems to be its most fundamental part, so that the soul or intellect seems to be the whole man, according to what is said in Ethics 9. (Aristotle, Nicomachean Ethics 9.4, 1166a16, a23.)

Reply Obj. 2: The whole man comes from the thigh of the begetter—insofar as the power of the seed coming from the thigh conduces to the union of soul and body by giving the matter its ultimate disposition, which necessitates the form, by reason of which union a man is a man—but not as though each part of man were caused by the power of the seed.

Reply Obj. 3: Original sin is called the sin of the entire nature, just as actual sin is called the personal sin; therefore, the comparison between actual sin and the one individual person is the same as that between original sin and the entire human nature handed on from our first parent, in whom was the beginning of sin and by whose will original sin is imputed as voluntary to all men. Therefore, original sin is in the soul insofar as it pertains to the human nature. Now, human nature is passed on from parent to child by the passing on of flesh into which subsequently the soul is infused; and from this the soul contracts the infection that makes it one nature with the transmitted flesh. For were it not united thereto so as to constitute one nature, it would not contract the infection, as neither does an angel by assuming a human body.

Reply Obj. 4: As within Adam’s nature was the nature of us all as in its origin, so too original sin, which is in us, was in that original sin as in its origin. For the nature, as already stated, receives original sin through itself, while the soul does so as a consequence.

Reply Obj. 5: A man begets his like in species through the power of his own form, namely, his rational soul, not that this is the immediate active principle in human generation, but because the generative force and things that act in the seed do not dispose the matter so as to make it a body fit to be perfected by a rational soul except insofar as they act as certain instruments of a rational soul. Nevertheless, this action does not go so far as to produce a rational soul, for the reasons already given.

Reply Obj. 6: The generator begets his like in species insofar as the begotten is produced by the action of the generator in order that it may share in his species; and this comes to pass by the begotten receiving a form like that of the generator. If, then, that form is not subsistent, and its own being consists merely in that it is united to that of which it is the form, it will be necessary for the generator to be the cause of the form itself, as is the case with all material forms. If, on the other hand, it is a form such that it has subsistence, and its own being is not entirely dependent on its union with matter, as in the case of the rational soul, then it suffices that the generator is the cause of the union of such a form with matter by disposing the matter for the form; nor need it be the cause of the form itself.

Reply Obj. 7: The disposition of the rational soul follows the very disposition of the body, both because it receives something from the body, and because forms are also diversified according to the diversity of their matter. This is why children are like their parents even in things pertaining to the soul, and not because one soul is transmitted by another.

Reply Obj. 8: Because properly speaking a soul is the act of a living body, and life is conditional upon heat and humidity, which are preserved in an animal by means of its blood, this is why it is said that the soul is in the blood, thus indicating the proper disposition of the body as matter perfected by the soul.

Reply Obj. 9: There are several opinions about the life of the embryo.

According to some, in human generation the rational soul, like the human body, is subject to stages of progression. They say that just as the human body is in the seed by way of power yet has not actually the perfection of a human body (which consists in the distinction of its organs), but gradually reaches this perfection through the power of the seed, so too at the beginning of the generation the soul is there, having in its power all the perfection that subsequently is to be seen in the perfect human being, yet not having it actually (since there is no sign of the soul’s activity) but attaining thereto by degrees; thus, at first there are indications of the action of the vegetative soul, then of the sensitive soul, and lastly of the rational soul. Gregory of Nyssa (Gregory of Nyssa (ca. 335–395 AD), called the “philosopher,” was the brother of Basil the Great and friend of Gregory Nazianzen; he was bishop of Nyssa in Cappadocia (see PG 45–46).) mentions this opinion (On Man). (Cf. Gregory of Nyssa, On the Making of Man 29 (PG 44:232–39). However, the work that Aquinas is referring to is by Nemesius of Emesa, under the title On the Nature of Man (PG 40:503–818).)

But this opinion cannot stand. For it means either that the soul itself, according to its own species, is in the seed from the very outset, deprived, however, of its perfect activities on account of a lack of organs, or that from the beginning there is in the seed some power or form that does not yet have the species of soul (just as the seed has not as yet the species of human body), but by the action of nature this very same thing gradually becomes a soul, at first one that is vegetative, then sensitive, and lastly rational.

The former alternative is rebutted first by the authority of the Philosopher. For he says in On the Soul 2 that the potential for life that is in the natural organized body, the act of which is the soul, does not exclude the soul, as we exclude it from the seed and the fruit. (Aristotle, On the Soul 2.1, 412b25–26.) Therefore, we gather that the seed is in potency to the soul in such a way that it lacks the soul. Second, because as the seed is not assimilated by an ultimate likeness to the members (or else its resolution would be a kind of corruption) but is the residue of the final digestion, as is said in On Animals 15, (Aristotle, On the Generation of Animals 1.18, 725a11–28, 726a26–28; 1.19, 726b10–24.) it was not yet, while in the body of the begetter, perfected by a soul; whence in the first instant of its separation, it could not have a soul. Third, granted that it was animated when it was separated, this cannot refer to the rational soul, because since it is not the act of a particular part of the body, it cannot be sundered when the body is sundered.

The second alternative is also clearly false. For seeing that a substantial form is brought into act not continuously or by degrees but instantaneously (else movement would needs be in the genus of substance just as it is in that of quality), that power that from the outset is in the seed cannot by degrees advance to the various degrees of soul. Thus, the form of fire is not induced in the air so as gradually to advance from imperfection to perfection, since no substantial form is subject to increase and decrease; rather, it is the matter alone that is changed by the previous alteration so as to be more or less disposed to the form. But the form does not begin to be in the matter until the last instant of this alteration.

Others say that, in the seed, there is at first the vegetative soul, and afterwards, while this remains, the sensitive soul is introduced by the power of the generator, and lastly the rational soul is introduced by creation, so that they posit in man three essentially different souls.

Against this, however, it is said: nor do we say that there are two souls in one man, as James and other Syrians write: one that is animal, by which the body is animated and which is mingled with the blood, the other spiritual, which obeys the reason. (Gennadius of Marseilles, Book of Ecclesiastical Dogmas 15 (PL 58:984).) Moreover, it is impossible for one and the same thing to have several substantial forms, because, since the substantial form makes a thing to be not merely in some respect but simply speaking, and it establishes this or that thing in the genus of substance, if the first form does this, the second form at its advent will find a subject already established with substantial being, and consequently, will accrue to it accidentally; and thus, it would follow that the sensitive and rational souls in man would be united accidentally to the body. Nor can it be said that the vegetative soul, which is the substantial form in a plant, is not the substantial form in a man, but a mere disposition to the form; for that which is in the genus of substance cannot be an accident of anything, as is said in Physics 1. (Aristotle, Physics 1.2, 185a31; 1.3, 186b32.)

Therefore, others say that the vegetative soul is in potency to the sensitive soul, and that the sensitive soul is its act; whence the vegetative soul, which at first is in the seed, is raised to the completion of the sensitive soul by the action of nature; and further, that the rational soul is the act and completion of the sensitive soul, so that the sensitive soul is brought to its own completion (that is, to the rational soul) not by the action of the generator but by that of the Creator. Therefore, they hold that the rational soul itself is in man partly from within, namely, as regards its intellectual nature, and partly from without, as regards its vegetative and sensitive nature.

Now, this is altogether impossible, because either it means that the intellectual nature is a soul distinct from the vegetative and sensitive souls—and thus, we return to the second opinion—or it means that these three natures constitute the substance of the soul wherein the intellectual nature will be formal, as it were, and the sensitive and vegetative natures, material. From this it would follow, since the sensitive and vegetative natures are corruptible, as brought out from matter, that the substance of the human soul would not be immortal. Moreover, this opinion is involved in the same incongruity as we have shown in the first opinion, namely, that a substantial form would be brought into act by degrees.

Others say that there is no soul in the embryo until it is perfected by the rational soul, and that life’s activities observed therein proceed from the soul of the mother. But this also is impossible, because living and non-living things differ in that living things are self-moving in respect of the activities of life, while non-living things are not. Therefore, self-nourishment and growth, which are activities proper to a living being, cannot result in the embryo from an extrinsic principle, such as the mother’s soul. Moreover, the mother’s nutritive power would assimilate food to the mother’s body and not to the body of the embryo, since self-nourishment serves the individual just as generation serves the species. Further, sensation cannot be caused in the embryo by the mother’s soul. Therefore, others say that there is no soul in the embryo before the infusion of the rational soul, but that there is a formative force there that exercises such activities of life within the embryo. This again is impossible because, since before the embryo attains to its ultimate completion, it shows signs of various life activities, these cannot be exercised by one power; so there must be a soul there having various powers.

We must, therefore, say differently that, from the moment of its severance, the seed contains not a soul but the power of a soul, one that is established in the spirit that is contained in the seed, which by nature is spumy and consequently contains corporeal spirit. Now, this power acts by disposing matter and forming it for the reception of the soul. And we must observe a difference between the process of generation in men or animals and that in air or water. For the generation of air is simple, since therein only two substantial forms appear, one that is voided and one that is induced, and all this takes place together in one instant, so that the form of water remains during the whole period preceding the induction of the form of air, without any previous dispositions to the form of air. On the other hand, in the generation of an animal, various substantial forms are apparent: first the seed, then blood, and so on, until we find the form of an animal or of a man.

Consequently, this kind of generation is not simple, but consists of a series of generations and corruptions. For it is not possible, as we have shown above, that one and the same substantial form is brought out into act by degrees. Thus, then, by the formative power that is in the seed from the beginning, the form of the semen is set aside and another form induced; and when this has been set aside, yet another is induced, and thus, the vegetative form is first induced; and this being set aside, a soul both vegetative and sensitive is induced; and this being set aside, a soul at once vegetative, sensitive, and rational is induced, not by the aforesaid power, but by the Creator. (Cf. ST I.118.2, ad 2.) And thus, it should be said that the embryo, before having a rational soul, is alive and has a soul, and when this is set aside, a rational soul is induced. And thus, it does not follow that two souls are together in the same body, nor that the rational soul is transmitted together with the seed.

Reply Obj. 10: Before it has the rational soul, the embryo is not a perfect being, but is on the way to perfection; and therefore, it is not in a genus or species save by reduction, just as the incomplete is reduced to the genus or species of the complete.

Reply Obj. 11: Although the soul is not in the seed from the beginning, the power of the soul is there, as stated above, which power is established in the spirit that is contained in the semen, and it is called the “power of the soul” because it comes from the soul of the generator.

Reply Obj. 12: Before the advent of the rational soul, the embryo is alive and has a soul, as stated above; therefore, we grant this argument.

Reply Obj. 13–15: The same answer applies to the thirteenth, fourteenth, and fifteenth objections.

Reply Obj. 16: The formative power that is from the outset in the seed remains even after the advent of the rational soul, just as the spirits also remain into which nearly the whole substance of the semen is converted. This power, which at first was formative of the body, afterwards regulates the body, just as heat also, which at first disposes matter to the form of fire, remains after the advent of the form of fire as an instrument of the form in activity.

Reply Obj. 17–18: This answer applies to the seventeenth and eighteenth objections.

Reply Obj. 19: Although the rational soul is not from the generator, its union with the body is in a manner from the generator, as stated above. Consequently, we say that a man is begotten.

Reply Obj. 20: There is not a twofold being in man, for the body should not be understood as from the begetter and the soul from the Creator in such a way that the being acquired by the body from its begetter is distinct from that which the soul acquires from its Creator; rather, the Creator gives being to the soul in the body, and the begetter disposes the body to participate in this being through the soul united to it.

Reply Obj. 21: Two agents that are altogether disparate cannot combine so that the one’s action terminates in the matter and the other’s in the form; but this is possible in the case of two coordinate agents, one of which is the instrument of the other. For the action of the principal agent sometimes extends to something that is beyond the range of the instrument’s action. Now, nature is as a certain instrument of the divine power, as we have shown above. (Q. 3, a. 8, ad 14; a. 7.) Therefore, it is not incongruous that the divine power alone produces the rational soul, while the action of nature extends no further than to giving the body the requisite disposition.

Reply Obj. 22: An intelligence existing in a body needs nothing corporeal to understand that which is, together with the intellect, the principle of the intellectual activity, as happens in sight; for the principle of vision is not only sight, but an eye composed of pupil and sight. However, it needs a body as an object, just as the sight needs the wall on which is the color, because images are compared to the intellect as colors to sight, as is said in On the Soul 3. (Aristotle, On the Soul 3.5, 430a16.) This is why the intellect is prevented from understanding when the organ of the imagination is injured; for so long as it is in the body, it needs images, not only as receiving from the images when it is acquiring knowledge, but also as referring the intelligible species to the images when it uses knowledge already acquired. For this reason, examples are necessary in the sciences.

Reply Obj. 23–24: From this we gather how to reply to the twenty-third and twenty-fourth objections.

Reply Obj. 25: This was the argument of Apollinaris, (Apollinaris was bishop of Laodicea (ca. 310–392 AD). He denied the existence of a rational human soul in Christ’s human nature, saying instead that it was replaced in him by the Logos, so that his body was a glorified and spiritualized form of humanity.) according to Gregory of Nyssa. (Gregory of Nyssa, On the Soul 6 [col. 206] (PG 45:187–220). These excerpts that come under the name De Anima are excerpts out of cc. 2 and 3 from the work of Nemesius of Emesa: On Human Nature (PG 40:535–608).) He was deceived, however, in failing to distinguish the action of nature, which is the procreation of the child, to which action God gives the complement, from the voluntary act of adultery wherein the sin consists.

Reply Obj. 26: The soul, being more perfect than material forms, would be able to produce its like if a rational soul could be produced otherwise than by creation, which is impossible. And this is owing to its perfection, as may be gathered from what has been said.

Reply Obj. 27: In God alone can there be one nature in several supposits; therefore, in him alone can there be generation without the imperfection of change and division. Thus, the higher creatures, which are indivisible and unchangeable in substance, such as the rational soul and the angels, are not generated; therefore, the lower creatures are, being divisible and corruptible.

Reply Obj. 28: The power that is in the seed is called “intellect” by the Philosopher, according to the Commentator, on account of a certain likeness, (Averroes, Commentary on the Metaphysics 7.9, comm. 31.) inasmuch as, like the intellect, the power’s action, is exercised without an organ.

Reply Obj. 29: This saying of the Philosopher refers to the sensitive but not the rational soul.