Summa contra Gentiles2.88 Chapter LXXXVIII. Arguments for proving that the human soul is formed from the semen

Nevertheless there are some objections to the foregoing.

For since man is an animal inasmuch as he has a sensitive soul; and the notion of animal applies univocally to man and other animals; it would seem that man’s sensitive soul is of the same genus as the souls of other animals. Now things of the same genus have the same manner of coming into being. Wherefore the sensitive soul of man, as also of other animals, comes into being through a force residing in the semen. But the intellective and sensitive soul are the same in man, as we proved above. Consequently it would seem that the intellective soul also comes into being through a seminal virtue.

Further. As Aristotle teaches {De Gener. Animal.), in point of time the fetus is an animal before it is a man. Now, while it is an animal and not a man, it has a sensitive and not an intellective soul: and there can be no doubt that this sensitive soul, even as in other animals, is formed by the active virtue of the semen. But that very same sensitive soul is potentially intellective, just as that animal is potentially a rational animal,—unless by chance it be said that the supervening intellective soul is a distinct substance, which has been refuted above. Therefore, seemingly, the substance of the intellective soul is caused by a virtue in the semen.

Again. Since the soul is the form of the body, it is united to the body in being. Now, things that are one in being are the term of one action and of one agent: for if there were several agents and consequently several actions, effects diverse in being would result. Consequently the being of soul and body must be the term of the one action of one agent. But, it is clear that the body results from the 1 See following ch. * Ch. Iviii, 2. iii. * Ch. Iviii.

action of a virtue in the semen. Therefore the soul which is its form is the effect of the same action, and not of some separate agent.

Moreover. Man generates his like in species by a virtue residing in the semen after separation. Now, every univocal agent generates its like in species through causing the form of the thing generated, which derives its species from that form. Therefore the human soul, whence man derives his species, is produced by a virtue residing in the semen.

Again. Apollinaris argues as follows. Whoever completes a work, co-operates with the agent. But, if souls are created by God, He completes the generation of children who are sometimes born of adulterers. Therefore God co-operates with adulterers; and this seemingly is inadmissible.

Again, in a book ascribed to Gregory of Nyssa we find arguments in support of the same statement. This is how he argues. Soul and body together make one thing, and this is one man. If therefore the soul is made before the body, or the body before the soul, one and the same thing will precede and follow itself: which is seemingly impossible. Therefore body and soul are made at the same time. But the body begins to exist at the separation of the semen. Therefore the soul also is brought into being through the separation of the semen.

Again. The operation of an agent would seem to be imperfect, if he does not bring an entire thing into being, but only some part thereof. Therefore if God were to bring the soul into being, while the body was formed by the virtue of the semen, which two things are parts of one, namely man, the operation of both God and the seminal virtue would seem to be imperfect; which is clearly inadmissible. Hence man’s soul and body are produced by one and the same cause. Now, it is clear that man’s body is produced by the virtue of the semen. Therefore the soul is also.

Again. In everything generated from seed, all the parts of the thing generated are together virtually contained in the seed, though they appear not actually. Thus in wheat or any other seed we see that the grass with stem, stalks, fruit, and beard are virtually contained in the original seed; afterwards the seed spreads forth and by a kind of natural consequence reaches perfection without taking to itself anything outside itself. Now it is clear that the soul is part of man. Therefore the human seed contains virtually the human soul; and this does not take its origin from any external principle.

Moreover. Things that have the same process and term must have the same principle of origin. Now in the generation of a man we find the same process and term in the body as in the soul. For the soul’s operations become more and more manifest, as the members are developed in shape and size: thus the operation of the nutritive soul is apparent at first; afterwards, the operation of the sensitive soul, and lastly, the body being fully developed, the operation of the intellective soul. Therefore the body and soul have the same principle. But the principle of origin in the body is through the separation of the semen. Therefore the same is the principle of the soul’s origin.

Again. That which is conformed to a thing, is fashioned by the action of the thing to which it is conformed: for instance the wax that is conformed to the seal, receives this conformity from the impression of the seal. Now it is evident that the body of a man or of any animal is conformed to its own soul; because its organs are so arranged as required by the soul’s operations to be exercised by them. Therefore the body is formed by the action of the soul: wherefore Aristotle says {2 De AnimaY that the soul is the efficient cause of the body. But this would not be so were not the soul in the semen: because the body is fashioned by the power that is in the semen. Therefore the human soul is in the semen: and consequently takes its origin from the separation of the semen.

Again. Nothing lives except by a soul. Now the semen is living. This is proved in three ways. First, because it is severed from a living being. Secondly, because the semen gives signs of vital heat and vital operations, which are indications of a living thing. Thirdly, because the seeds of plants when put into the soil, unless they had life in themselves, could not gather heat from the soil, which is inanimate, so as to live. Therefore the soul is in the semen: and consequently it originates with the severing of the semen.

Moreover. If the soul were not before the body, as we have proved and did not begin to be at the severance of the semen, it follows that the body is formed first, and the newly created soul infused into the body afterwards. Now, were this true, it would further follow that the soul is for the sake of the body: because that which is on another’s account is found to come after it; even so clothes are made for man. But this is false, since on the contrary the body is for the soul’s sake, since the end is always of greater excellence. We must therefore conclude that the soul originates together with the severance of the semen.