Article 11 — Whether the sensitive and vegetative souls are created or transmitted through the seed

The eleventh point of inquiry is whether the sensitive and vegetative souls are created or transmitted through the seed. (Parallel texts: ST I.118.1; SCG II.86; Quodlibet IX, q. 5, a. 1; In II Sent. 18.2.3.)

Obj. 1: And it would seem that they are created. For things of the same account come into being in the same manner. Now, the sensitive and vegetative souls in man are of the same species or account as in beasts and plants. But in man they are created, since they are substantially one with the rational soul, which is created, as shown above. (Q. 3, a. 9.) Therefore, the sensitive and vegetative souls in animals and plants are also created.

Obj. 2: It might be said that the sensitive and vegetative soul is in plants and beasts as a form and perfection, whereas in man they are as a disposition.

On the contrary, the nobler a thing is, the more noble is its manner of coming into being. Now, it is nobler to be a form and perfection than to be a disposition. Consequently, if the sensitive and vegetative souls in man, in whom they are as dispositions, come into being by creation, which is the noblest manner of coming into being, because the noblest creatures originate in this manner, seemingly much more so are they created in plants and beasts.

Obj. 3: The Philosopher says: that which truly exists, that is, substance, is not accidental to anything. (Aristotle, Physics 1.3, 186b33.) If, then, the sensitive and vegetative souls are as substantial forms in beasts and plants, they cannot be accidental dispositions in man.

Obj. 4: In living things, something is produced by the power of the generator through the power residing in the seed. Now, the sensitive and vegetative souls are not actually in the seed. Since, then, nothing acts except inasmuch as it is in act, it seems that the sensitive and vegetative souls cannot be produced by the power in the seed, and thus, they are produced not by generation but by creation.

Obj. 5: You will say perhaps that though the power that is in the seed is not actually the sensitive soul, yet it acts in the power of the sensitive soul that was in the father from whom the seed issues.

On the contrary, that which acts in the power of another acts as its instrument. Now, an instrument does not move except as moved: while mover and moved must be together, as is said in Physics 7. (Aristotle, Physics 7.2, 243a3–23.) Since, then, the power that is in the seed is not joined to the sensitive soul of the generator, it seems that it cannot act as its instrument or in its power.

Obj. 6: An instrument stands to the principal agent as a moved and commanded power to a motive and commanding power, which is an appetitive and motive force. Now, a commanded and moved power does not move anything if it be severed from the motive and commanding power, as may be seen in the severed limbs of an animal. Neither, then, can the power in the separated seed act in the power of the generator.

Obj. 7: When an effect falls short of the perfection of its cause, it cannot compass the action proper to that cause, since diversity of actions argues diversity of natures. Now, it is certain that the power in the seed, although an effect of the generator’s sensitive soul, falls short of its perfection. Therefore, it cannot accomplish the action that belongs properly to the sensitive soul, namely, the production of another soul like to it in species.

Obj. 8: Corruption of the subject leads to corruption of the form and power. Now, in the process of generation, the semen, according to Avicenna, is corrupted and receives another form. (Avicenna, The Metaphysics of the Healing 6.4; cf. 4.2, 6.1–2.) Therefore, the power that was in the seed is also corrupted, and consequently, a sensitive soul cannot be produced by it.

Obj. 9: Lower natures act only by means of heat and other active and passive qualities. Now, heat cannot give being to the sensitive soul, because nothing acts beyond its own species, nor can the thing made be nobler than its maker. Therefore, the sensitive and vegetative soul cannot be led forth into being by any natural agent, and consequently, it is created.

Obj. 10: A natural agent acts not by exerting influence on matter but by transmuting it. Now, the transmutation of matter can lead only to an accidental form. Therefore, a natural agent cannot produce a sensitive and vegetative soul, which are substantial forms.

Obj. 11: Sensitive and vegetative souls have a certain “whatness,” and this whatness is brought into being by something else. Moreover, it did not exist before generation except insofar as the matter was able to have it. Hence, it must be produced by an agent that does not work from matter, and this is no other than the creating God.

Obj. 12: Animals produced from seed are nobler than those engendered from decomposition, for they are more perfect and reproduce their like. Now, the souls of animals engendered from decomposition are created, since no agent of like species can be assigned by which they can be produced. Therefore, it would seem that there is much more reason for the souls of animals produced from seed to be created.

Obj. 13: But you will say that the sensitive soul, in animals generated by decomposition, is produced through the power of a heavenly body, just as they are produced in other animals by the formative power in the seed.

On the contrary, according to Augustine, a living substance surpasses all inanimate substances. (Augustine, On True Religion 29, 55 (PL 34:145, 169–72).) Now, a heavenly body is not a living substance, for it is without soul. Therefore, a sensitive soul, being a principle of life, cannot be produced by its power.

Obj. 14: But you will say that a heavenly body can be the cause of a sensitive soul, inasmuch as it acts in the power of an intellectual substance that moves it.

On the contrary, that which is received into another is received according to the mode of the recipient and not according to its own mode. Therefore, if the power of an intellectual substance is received by an inanimate heavenly body, it will not be there as a vital power that can be a principle of life.

Obj. 15: An intellectual substance is not only alive but it also understands. If, then, by its power a heavenly body can be so moved by it as to give life, it will be able likewise to give intelligence, so that the rational soul will be produced by the begetter, which is false.

Obj. 16: If the sensitive soul is produced by a natural agent and not by creation, it must be produced either by the body or by the soul. It is not produced by the body, because then a body would act beyond its species. Nor is it produced by the soul, because then either the whole soul of the father would be transmitted to his child, and thus, the father would remain without a soul; or part of it would be transmitted, and thus, the whole soul would not remain in the father; and either alternative is false. Therefore, the sensitive soul is not produced by the begetter but by the Creator.

Obj. 17: The Commentator says that no cognitive power comes from the action of mixed elements. (Averroes, On the Soul 3.4.) Now, the sensitive soul is a cognitive power. Therefore, it is not from the elements, and consequently, not from an action of nature, inasmuch as in lower things no action of nature is independent of the action of the elements.

Obj. 18: No form that is not subsistent can cause movement; therefore, according to the Philosopher, movement is not caused by the forms of elements but only by the generator, and that which removes an obstacle. (Aristotle, Physics 8.4, 255b23–256a3.) But the sensitive soul is a cause of movement, since every animal is moved by its own soul. Therefore, the sensitive soul is not a mere form but a self-subsistent substance. It is also certain that it is not composed of matter and form. Now, all such substances are brought into being by creation and not otherwise. Therefore, the sensitive soul comes into being by creation.

Obj. 19: You will say, perhaps, that the sensitive soul does not by itself move the body, but that the ensouled body moves its very self.

On the contrary, the Philosopher proves that in everything moving its very self, there must be one part that is mover only and another that is moved. (Aristotle, Physics 8.5, 257b12, 258a18–25.) Now, the body cannot be mover only, because no body moves unless it be moved. (Aristotle, Physics 8.4, 256a2–3.) Therefore, the soul is a mover only, and thus the sensitive soul will have an activity in which the body has no share, and consequently, will be a subsistent substance.

Obj. 20: But you will say that the sensitive soul moves according to the command of the appetitive power, whose act is shared by both soul and body.

On the contrary, in an animal, there is not only a commanding force but also a force executing movement, and the activity of this latter power cannot, for the reasons already given, be common to both soul and body. And consequently, the sensitive soul must have a certain activity through itself. Therefore, it is a self-subsistent substance, and is brought into being by creation and not by natural generation.

On the contrary (1) it is written: let the waters bring forth the creeping creature having a living soul (Gen 1:20), so that it seems that the sensitive souls of reptiles and of other animals come from the action of corporal elements.

Furthermore (2), as the father’s body is in relation to his soul, so is the son’s body in relation to his soul. Therefore, reciprocally, as the son’s body is to his father’s, so is the son’s soul to his father’s. Now, the son’s body is transmitted from the father’s. Therefore, the son’s soul is transmitted from his father’s.

I answer that philosophers are divided in their opinions about the production of substantial forms. Some have said that the natural agent only disposes the matter, and that the form, which is the ultimate perfection, arises from supernatural principles.

This opinion is shown to be false chiefly on two counts.

First, seeing that the being of natural and corporeal forms consists solely in their union with matter, it seems that it belongs to the same agent to produce them and to transmute matter.

Second, inasmuch as these forms do not surpass the power, order, and faculty of the principles acting in nature, there seems to be no need to trace back their origin to higher principles; this is why the Philosopher says that flesh and bone are generated by the form that is in this or that flesh and bone, (Aristotle, Metaphysics 7.8, 1034a1–8.) and according to his opinion, the natural agent not only disposes the matter but brings forth the form into act, which is contrary to the above opinion.

Nevertheless, we must exclude the rational soul from this generality of forms. For it is a substance subsisting through itself; therefore, its own being does not consist solely in its union with matter. Otherwise, it could not exist apart from the body, the possibility of which is also shown by its activity, which belongs to the soul according to its very self, without any communion with the body. Nor can it act otherwise than it exists. For that which does not exist through itself is not active through itself. Again, the intellectual nature transcends the entire order and faculty of material and corporeal principles; for by understanding, the intellect is able to rise above every corporeal nature, which would not be the case if its nature were confined within the limits of a corporeal nature.

Now, neither of these things can be said of the sensitive and vegetative souls. That the being of these souls cannot consist otherwise than in union with the body, is shown by their activities, which cannot occur without a bodily organ; therefore, absolutely speaking they have no being independently of the body. For this reason, they cannot exist apart from the body, nor be brought into being except insofar as the body is brought into being. Consequently, just as the body is produced by the act of the generating nature, so too are these souls. But to maintain that they come into existence separately appears to return to the opinion of those who held that these souls survived their bodies, whereas both these opinions are condemned in Of Church Doctrine. (Gennadius of Marseilles, Book of Ecclesiastical Dogmas 17 (PL 58:984–85).)

Also, these souls do not transcend the order of natural principles. This is evident if we consider their activities. For the order of actions is according to the order of natures. Now, we find some forms that do not extend themselves beyond what can be done through material principles; for example, the elementary forms and those of mixed bodies do not go beyond the action of the hot and the cold; therefore, they are wholly immersed in matter.

On the other hand, although the vegetative soul does not act except by means of the qualities aforesaid, its action attains to something that is beyond the reach of these qualities, namely, to the production of flesh and bone, the fixation of the terminus of growth, and the like; whence it still remains within the order of material principles, though not so much as the forms in question.

But the sensitive soul does not of necessity act by means of hot and cold, as is clear in the acts of sight, imagination, and the like; yet, for their activities is required a determinate balance of hot and cold, for the constitution of their organs, without which the aforesaid actions cannot occur. Hence, the sensitive soul does not wholly transcend the order of material principles, although it is not lowered to their level as much as are the above-mentioned forms.

The rational soul, however, also performs an action that surpasses the power of hot and cold, nor does it exercise it through the power of the hot and cold, nor by means of a bodily organ. Therefore, it alone transcends the order of natural principles, while the sensitive soul in beasts and the vegetative soul in plants do not.

Reply Obj. 1: Although the sensitive soul in man and dumb beasts is of the same account as regards its genus, it is not of the same account as regards its species, just as a man and a beast are not the same animal in species. Consequently, the activities of the sensitive soul are far more noble in man than in beasts, as is clear with touch and the interior powers of apprehension. Nor is it necessary that things that are in a genus, if they differ in species, have the same manner of coming into being, as is clear in the case of animals engendered from seed and from decomposition, since these agree in genus but not in species.

Reply Obj. 2: In man, the sensitive soul is said to be as a disposition not as though it differed in substance from the rational soul, and were a disposition thereto, but because the sensitive is distinguished from the rational in man only as one power is from another. On the other hand, in a beast the sensitive soul differs from the rational soul in man as one substantial form from another. Nevertheless, as the sensitive and vegetative powers in man flow from the essence of the soul, so do they in beasts and plants. But with this difference: in plants there flow only vegetative powers from the essence of the soul, in beasts not only vegetative but also sensitive powers, from which latter their soul is denominated, while in man besides these flow also the intellectual powers, from which he is denominated.

Reply Obj. 3: The substance from which the sensitive power flows, both in beasts and in man, is the substantial form, while in both cases the power is an accident.

Reply Obj. 4: The sensitive soul is not actually in the seed according to its own proper species, but as in an active power, just as a house is actually in the mind of the builder as in an active power; and thus are bodily forms in the heavenly powers.

Reply Obj. 5: An instrument is understood to be moved by the principal agent so long as it retains the power communicated to it by the principal agent; thus, the arrow is moved by the archer as long as it retains the force wherewith it was shot by him. Thus, in heavy and light things, that which is generated is moved by the generator, as long as it retains the form transmitted thereby, so that the seed also is understood to be moved by the soul of the begetter, as long as it retains the power impressed by that soul, although it is corporeally separated from it. And the mover and the thing moved must be together at the commencement of the movement but not throughout the whole movement, as is evident in the case of projectiles.

Reply Obj. 6: The soul’s appetitive power has no command except on the body united to it; therefore, the separated part does not obey the behest of the appetitive soul. Nor is the seed moved by the begetter’s soul through a command, but through the transfusion of a certain power that remains in the seed even after its separation.

Reply Obj. 7: The sensitive and vegetative souls are brought out from the potency of matter just as other material forms are as well, for the production of which a power is needed that transforms matter. Now, the power that is in the seed has this power, although it falls short of the soul’s other actions. For just as the soul transforms matter so as to change it entirely into the body in the action of self-nourishment, so by the aforesaid power matter is transformed so as to result in conception. Consequently, nothing hinders this same power from working, in its power, in this respect for the sake of the sensitive soul’s action.

Reply Obj. 8: This same power is rooted in the spirit enclosed within the seed as its subject. Now, according to Avicenna, nearly all the seed is changed into spirit. (Cf. Avicenna, The Metaphysics of the Healing 6.4; 8.2.) Therefore, although the corpulent matter, from which the embryo is formed, undergoes many changes in generation, the subject of that power is not destroyed.

Reply Obj. 9: As heat acts as the instrument of the substantial form of fire, so there is nothing to prevent it from acting as the instrument of the sensitive soul in bringing a sensitive soul into act, though it cannot do so by its own proper power.

Reply Obj. 10: Matter is transmuted not only by an accidental but also by a substantial change, for both forms preexist in the potency of matter. Therefore, a natural agent, which transmutes matter, is the cause not only of the accidental but also of the substantial form.

Reply Obj. 11: The sensitive soul, since it is not a subsistent reality, is not a whatness, just as neither are other material forms; rather, it is part of a whatness, and its own being is in its concretion with matter. Therefore, the sensitive soul’s being produced is nothing more than the matter’s being transmuted from potency to act.

Reply Obj. 12: The more imperfect a thing is, the fewer the requisites for its constitution. Therefore, since animals engendered from decomposition are more imperfect than those engendered from seed, in the former only the power of a heavenly body is sufficient, which power is at work also in the seed, although it does not suffice without the power of the soul for the production of animals from seed. For the power of a heavenly body remains in the lower bodies insofar as they are transmuted by it as by the first cause of alteration. For this reason, the Philosopher says, in On Animals, that all these lower bodies are full of a soul’s powers. (Aristotle, The Generation of Animals 2.1, 734a1–735a30; 2.3, 736a25–737a35; 2.4, 737b8–20, 740a25–741a33.) But the heaven, though not alike in species to the animals engendered from decomposition, is like them insofar as an effect virtually persists in its active cause.

Reply Obj. 13: Although the heavenly body is not alive, it acts in the power of a living substance by whom it is moved, whether this be an angel or God. According to philosophers, however, heavenly bodies are ensouled and living.

Reply Obj. 14: The power of a spiritual substance moving it is found in a heavenly body and its movement, not as a form having complete natural being, but after the manner of an intention, as power is in the craftsman’s tool.

Reply Obj. 15: As stated above, the rational soul surpasses the entire order of corporeal principles; therefore, no body can act even instrumentally for its production.

Reply Obj. 16: The sensitive soul is produced in the embryo neither by the action of the body nor by a separation from a soul, but by the action of the formative power that is in the seed from the soul of the begetter, as stated above.

Reply Obj. 17: It is denied that a cognitive power comes from the action of the elements, as though the powers contained in the elements would suffice for them just as they suffice to cause hardness or softness. But it is not denied that they can cooperate in some way instrumentally.

Reply Obj. 18: The sensitive soul causes movement by its appetite. Now, the function of the sensitive appetite belongs not only to the soul but also to the composite; hence, this power has a determinate organ. Therefore, we cannot conclude that the sensitive soul has an activity independent of the body.

Reply Obj. 19: A body can cause a movement without itself moving with the same species of movement as that which it causes, although it cannot move another unless it is moved in some way; for the heavenly body causes alteration without itself being altered, but it does move locally; and in like manner, the organ of the appetitive power causes local movement, without being so moved, whereas it is in a certain way altered locally. For the sensitive appetite’s activity does not occur without a corporeal alteration, as is clear in cases of anger and like passions.

Reply Obj. 20: The motive force that executes a movement is a disposition of the movable thing, whereby it is naturally apt to be moved by such a mover, more than it is a mover through itself.