Summa contra Gentiles2.89 Chapter LXXXIX. Solution of the foregoing arguments

For the easier solution of the foregoing arguments, we must first of all set down certain points, in order to explain the order and process of the generation of man, as well as of animals in general.

In the first place then it must be observed that the opinion of those is false who say that the vital operations that appear in the embryo before its ultimate completion, do not proceed from a soul or soul's power, existing therein, but from the soul of the mother. For if this were true, the embryo will no longer be an animal: since every animal consists of soul and body. Moreover vital operations do not proceed from an * De Great. Horn., loc. cit. * Ch. Ixxxiii.

extrinsic active principle, but from an internal force; and it is in this that inanimate things differ from the living, to which it properly belongs to move themselves. Because that which is nourished assimilates nourishment: wherefore in the subject nourished there must needs be an active nutritive power, since the agent produces its like. And much more evident is this in the operation of the senses: because to see and to hear are competent to a person through some faculty existing in him and not in another. Wherefore if the embryo is observed to be nourished and even to sense before its final development, that cannot be ascribed to the soul of the mother.

And yet it cannot be said that the soul, as to its complete essence, is in the semen from the very beginning, and that the operations of the soul are not apparent on account of the lack of organs. For, since the soul is united to the body as its form, it is not united to a body other than one of which it is properly the act. Now the soul is the act of an organic body} Consequently the soul is not actually in the semen before the organization of the body, but only potentially or virtually. Wherefore Aristotle says (2 De AnimaY that seed and fruit are potentially living as long as they put aside, i.e., are without, the soul; yet the thing of which the soul is the act, is potentially living, hut is not without a soul. It would also follow, if the soul were in the semen from the beginning, that the generation of an animal would be by the mere severance, as happens in annulose animals, where two are made from one. For if the semen were animated as soon as severed, it would at once have a substantial form. Now every substantial generation precedes, and does not follow, the substantial form; and if any changes follow the substantial form, they are directed, not to the being but to the well-being of the thing generated. Accordingly the generation of the animal would be completed in the mere severance of the semen: and all subsequent changes would have nothing to do with generation.

Even more absurd would this be if applied to the rational soul:—both because it cannot possibly be divided according to the division of the body, so that it be possible for it to be in the semen after severance:—and because it would follow that whenever pollution occurs without conception taking place, rational souls would nevertheless be multiplied.

Nor can it be asserted, as some say, that although from the moment of severance the soul is not in the semen actually but virtually, on account of the lack of organs; yet this very virtue of the semen (which is a body capable of receiving organs though it has them not actually) is proportionately a potential but not an actual soul to the semen; and that, since the life of a plant requires fewer organs than the life of an animal, when first the semen is sufficiently prepared for plant-life, this same virtue of the semen becomes a vegetative soul; and then, when the organs have been yet more perfected and multiplied, the same virtue advances to the state of a sensitive soul; and further still, the form of the organs being perfected, the same soul becomes rational, not indeed by the action of this seminal virtue, but by the action of an external agent, for which reason they imagine Aristotle to have said that the intellect is from without (De Gener. Animal.). For according to this opinion it would follow that the same identical virtue is at one time a purely vegetative soul, and afterwards a sensitive soul: so that the substantial form itself would be perfected more and more by stages. It would also follow that the substantial form would be brought from potentiality to act not at once but by degrees. And again, that generation, like alteration, is a continuous movement. All of which things are impossible in nature. A conclusion still more inadmissible would follow, namely that the rational soul is mortal. For nothing that accrues as a form to that which is corruptible makes it naturally incorruptible, else a corruptible thing would be changed into an incorruptible one, which is impossible, since they differ in genus, as stated in lo Metaph} Now the substance of the sensitive soul, since in the aforesaid process it is stated to be generated accidentally by the generated body, must needs be corruptible at the corruption of the body. If therefore the same soul becomes rational by a light introduced within it, which light is related to it as a form (for the sensitive is potentially intellective); it follows of necessity that the rational soul perishes when the body perishes. And this is impossible: as we proved above, and as the Catholic faith teaches.

Therefore the self-same virtue which is severed together with the semen and is called the formative virtue, is not the soul, nor does it become the soul in the process of generation: but, since it is based, as on its proper subject, on the (vital) spirit contained in the frothy semen, it causes the formation of the body in so far as it operates by virtue of the father's soul, to whom generation is ascribed as the principal agent, and not by virtue of the soul of the person conceived, even after the soul is in that person: for the subject conceived does not generate itself, but is generated by the father. This is clear to anyone who considers each power of the soul separately. For it cannot be ascribed to the soul of the embryo by reason of the generative power; not only because the generative power does not exercise its operation until the work is completed of the nutritive and augmentative powers which are its auxiliaries, since to generate belongs to that which is perfect; but also because the work of the generative power is directed, not to the perfection of the individual, but to the preservation of the species. Nor again can it be ascribed to the nutritive power, the work of which is to assimilate nourishment to the subject nourished, which is not apparent here; since in the process of formation the nourishment is not assimilated to something already existing, but is advanced to a more perfect form and more approaching to a likeness to the father. Likewise neither can it be ascribed to the augmentative power: since it belongs to this power to cause a 1 D. 9,, i. Ch. Ixxix.

change, not of form, but of quantity. As to the sensitive and intellective part, it is clear that it has no operation appropriate to such a formation. It remains then that the formation of the body, especially as regards the foremost and principal parts, is not from the form of the subject generated, nor from a formative power acting by virtue of that form, but from (a formative power) acting by virtue of the generative soul of the father, the work of which soul is to produce the specific like of the generator.

Accordingly this formative power remains the same in the aforesaid spirit from the beginning of the formation until the end. Yet the species of the subject formed remains not the same: because at first it has the form of semen, afterwards of blood, and so onwards until it arrives at its final complement. For although the generation of simple bodies does not proceed in order, since each of them has an immediate form of primary matter; in the generation of other bodies, there must be an order in the generations, by reason of the many intermediate forms between the first elemental form and the final form which is the term of generation; wherefore there are a number of generations and corruptions following one another.

Nor is it unreasonable if one of the intermediates be generated and then at once interrupted, because the intermediate stages have not a complete species but are on the way to a species: hence they are generated, not that they may remain, but that the final term of generation may be reached through them. Nor need we wonder if the transmutation of generation be not throughout continuous, and that there are many intermediate generations; for this happens also in alteration and growth, since neither alteration nor growth is continuous throughout, but only local movement is truly continuous, as we find proved in 8 Physic."

Accordingly, the more noble a form is and the further removed it is from the elemental form, the more numerous must needs be the intermediate forms, through which the ultimate form is reached by degrees, and consequently the more numerous will be the intermediate generations. Wherefore in the generation of an animal or a man in which the form is most perfect, there are many intermediate forms and generations, and consequently corruptions, since the generation of one is the corruption of another. Therefore the vegetative soul, which comes first, when the embryo lives the life of a plant, is corrupted, and is succeeded by a more perfect soul which is both nutritive and sensitive, and then the embryo lives an animal life; and when this is corrupted it is succeeded by the rational soul introduced from without: although the preceding souls were produced by the virtue in the semen.

Keeping these points before the mind, it is easy to answer the objections.

For in reply to the first objection, where it is stated that the sensitive soul must have the same manner of origin in man and in irrational animals, because animal is predicated of both univocally,—we say that this is not necessary. Because although the sensitive souls in man and dumb animals agree generically, they differ specifically, like the things of which they are the forms. For just as the animal that is a man differs specifically from other animals in the point of being rational, so the sensitive soul of man differs specifically from the sensitive soul of a dumb animal in this, that it is also intellective. Wherefore the sensitive soul in the dumb animal has no more than the sensitive faculty, and consequently neither its being nor its operation is raised above the body; and so it must needs be generated together with the body, and perish when the body perishes. On the other hand the sensitive soul in a man, through having besides the sensitive nature an intellective power in consequence of which it follows that it is raised above the body both in being and in operation, is neither generated through the generation of the body, nor perishes through the body's corruption. Hence the different manner of origin in the aforesaid souls is not on the part of the sensitive faculty whence the generic nature is taken, but on the part of the intellective faculty, whence the specific difference is derived. Therefore we can conclude a difference not of genus but only of species.

When it is objected in the second place that the thing conceived is an animal before a man, this does not prove that the rational soul is transmitted together with the semen. Because the sensitive soul whereby it was an animal does not remain, but is succeeded by a soul that is both sensitive and intellective, whereby it is at the same time both animal and man, as explained above.

The statement in the third objection, that the actions of different agents do not terminate in one thing made, must be understood as referring to different agents of which one is not ordered to the other. For if they be ordered the one to the other, they must have one effect: for the first active cause acts on the effect of the secondary active cause more intimately than does the secondary cause: hence we find that an effect produced by a principal agent through an instrument is more properly ascribed to the principal agent than to the instrument. Now it happens sometimes that the action of the principal agent attains to something in the effect produced, to which the action of the instrument does not attain: thus the vegetative power produces the species of flesh, which the heat of fire that is its instrument cannot produce, although it acts dispositively thereto by dissolving and consuming. Since then every active force of nature is compared to God as an instrument is compared to the first and principal agent, nothing hinders the action of nature, in one and the same subject generated which is a man, from terminating in a part of man and not in the whole which is the effect of God's action. Accordingly the human body is fashioned at the same time both by the power of God as the principal and first agent, and by the power of the semen as secondary agent: but God's action produces the human soul, which the seminal power cannot produce, but to which it disposes.

Hence the reply to the fourth objection is clear: because a man begets his like in species, in so far as the seminal virtue in him operates dispositively towards the ultimate form whence man derives his species.

That God should co-operate with adulterers in the action of nature involves no contradiction. For it is not the nature but the will that is evil in adulterers: and the action which proceeds from their seminal virtue is natural and not voluntary. Wherefore it is not unreasonable that God co-operate in their action by giving it its ultimate perfection.

As to the sixth objection, it is clear that the conclusion does not necessarily follow. For even if we grant that man's body is fashioned before the soul is created, or vice versa, it does not follow that the self-same man precedes himself: since a man is not his body nor his soul. But it follows that some part of him precedes the other. In this there is nothing unreasonable: because matter precedes form in point of time; matter, that is to say, considered as being in potentiality to form, but not as actually perfected by a form, for as such it is simultaneous with the form. Accordingly the human body, considered as in potentiality to the soul, and as not yet having a soul, precedes the soul in point of time: but then it is human, not actually, but only potentially. On the other hand when it is human actually, as being perfected by the human soul, it neither precedes nor follows the soul, but is simultaneous with it.

Nor again does it follow, if the soul is not produced by the seminal virtue, but only the body, that the operation both of God and of nature is imperfect, as the seventh argument inferred. Because both body and soul are made by the power of God: although the fashioning of the body is from Him by means of the natural virtue in the semen, whereas He produces the soul immediately. Neither does it follow that the action of the seminal virtue is imperfect; since it fulfils the purpose for which it is intended.

It must also be noted that the seed contains virtually whatever does not surpass a corporeal virtue, for instance the grass with the stem, stalks, and so forth. Whence we cannot conclude that the part of man which surpasses the whole corporeal virtue, is contained virtually in the seed, as the eighth argument inferred.

That the operations of the soul seem to develop in the process of human generation, according as the parts of the body develop, does not prove that the human soul and body have the same principle, as the ninth argument suggested: but it proves that the disposition of the body's parts is necessary for the soul's operation.

The statement of the tenth objection, that the body is conformed to the soul, and that for this reason the soul fashions a body like to itself, is partly true and partly false. For if it be understood of the soul of the begetter, the statement is true; whereas it is false if it be referred to the soul of the begotten. Because the body is not formed by the virtue of the soul of the begotten, as regards the body's foremost and principal parts, but by the virtue of the soul of the begetter, as we proved above. For all matter is similarly configured to its form; and yet this configuration results not from the action of the subject generated but from the action of the generator.

As to the eleventh objection about the life of the semen at the beginning of its severance:—it is clear from what has been said that it is not living except potentially: wherefore it has a soul then not actually but virtually. In the process of generation it has a vegetative and a sensitive soul by the virtue of the semen, which do not remain but pass away when the rational soul takes their place.

Nor again, if the fashioning of the body precedes the human soul, does it follow that the soul is for the sake of the body, as the twelfth objection inferred. For one thing is for another's sake in two ways. First, for the sake of its operation, or preservation, or any like thing consequent upon being: and the like are posterior to the thing for the sake of which they are: thus clothes are for man, and tools for the workman. Secondly, a thing is for another's sake, i.e. for the sake of its being; and thus a thing which is for the sake of another precedes the latter in the order of time but follows it in the order of nature. It is in this way that the body is for the sake of the soul: just as all matter is for the sake of a form. It would be otherwise if from soul and body there resulted a thing that is not one in being; as those assert who deny that the soul is the form of the body.