Summa contra Gentiles2.83 Chapter LXXXIII. That the human soul begins to exist with the body

Since, however, the same things are found to have both a beginning of being and an end of being, it may seem to some one that, since the human soul has no end of its being, neither has it had any beginning of being, but always has been. And seemingly this can be proved by the following arguments.

For that which will never cease to be, has the power to be always. And that which has the power to be always, can never be truly said not to he: since a thing’s duration in existence extends as far as its power to exist. Now of everything that has begun to be it is at some time true to say that it is not. Therefore that which will never cease to be, at no time begins to be.

Further. The truth of intelligibles is not only incorruptible, but, for its own part, is eternal: because it is necessary; and whatever is necessary is eternal, since for that which necessarily is, not to be is an impossibility. Now it is from the incorruptibility of intelligible truth that the soul is proved to have incorruptible being. Therefore by similar reasoning, from its eternity we can prove the eternity of the soul.

Moreover. A thing is not perfect if it lack several of its principal parts. Now it is clear that the principal parts of the universe are intellectual substances, to which genus, as shown above, human souls belong. Consequently if every day as many human souls begin to exist as men are born, it is evident that many of its principal parts are added to the universe every day, and that it lacks many such parts. Therefore it follows that the universe is imperfect: which is impossible.

Furthermore some argue from the authority of Holy Writ. For it is stated (Gen. i.) that on the seventh day God ended His work which He had made: and He rested... from all His work which He had done. But this would not be so, if He made new souls every day. Therefore new human souls do not begin to exist, but they have existed from the beginning of the world.

For these, then, and like reasons some, supposing the world to be eternal, have said that as the human soul is incorruptible, so has it existed from eternity. Hence those, namely the Platonists, who maintained that human souls in their universality are immortal, held that they have also existed from eternity, and are united to bodies at one time, at another separated from them, this vicissitude depending on certain fixed periods of years.” On the other hand, those who maintained that human souls are immortal in respect of some one thing which remains over from all men after death, held that this same one thing has existed from eternity; whether it be the active intellect alone, as Alexander said, or, besides this, the passive intellect, as Averroes asserted. This too is apparently the meaning of Aristotle’s words: since, speaking of the intellect, he says that it is not only incorruptible, but also perpetual.

Some, however, professing the Catholic faith, yet imbued with the teachings of the Platonists, have held a middle course. For since, according to the Catholic faith, nothing is eternal besides God, they maintained, not that human souls are eternal, but that they were created with or rather before the visible world, and yet are united anew to bodies. Of those who professed the Christian faith Origen was the first to hold this opinion, and afterwards several followed him. In fact, this opinion survives to this day among heretics, of whom the Manichees agree with Plato in asserting the eternity and transmigration of souls.

But it can be easily proved that the foregoing opinions are not founded upon truth. For we have already shown above that there is not but one possible or active intellect for all. Wherefore it remains for us to proceed against those opinions which state that there are many human souls, but that they existed before bodies, either from eternity or from the formation of the world. This would seem unreasonable for the following reasons.

For it was shown above that the soul is united to the body as its form and act. Now although act is naturally prior to potentiality, yet in one and the same subject it is posterior to it in time: since a thing is moved from potentiality to act. Wherefore the seed that is potentially living precedes the soul which is the act of life.

Again. It is natural to every form to be united to its proper matter: else that which is made of form and matter would be something beside nature. Now that which is becoming to a thing according to nature is ascribed to it before that which is becoming thereto beside nature: since what becomes a thing beside nature is in that thing accidentally, whereas what is becoming to it according to nature is in it per se; and that which is accidental always comes after that which is per se. Therefore it is becoming to the soul to be united to the body before being separated from the body. Therefore it was not created before the body to which it is united.

Moreover. Every part that is separated from its whole is imperfect. Now the soul, since it is a form, as proved above, is a part of the human species. Consequently as long as it exists by itself apart from the body, it is imperfect. But the perfect precedes the imperfect in the order of natural things. Therefore it is not becoming to the order of nature that the soul should have been created apart from the body before being united to the body.

Moreover. If souls were created without their bodies, we must inquire how they came to be united to those bodies. For this was either by force or by nature. If by force; since whatever is the result of force is against nature, it follows that the union of soul and body is unnatural. Wherefore man, who is composed of both, is something unnatural: and this is clearly false. Moreover, intellectual substances are of a higher order than heavenly bodies. Now nothing violent or contrary is to be found in heavenly bodies. Much less, therefore, is there in intellectual substances. On the other hand, if souls are united to bodies naturally, it follows that as soon as they were created souls had a natural desire to be united to bodies. Now the natural appetite is forthwith brought into act unless there be an obstacle, as instanced in the movement of heavy and light bodies: because nature always works in the same way. Consequently, from the very moment of their creation they would have been united to bodies unless there were something to prevent it. But everything that hinders the realization of the natural appetite does violence thereto. Therefore it was by violence that at some time souls were separate from bodies. Now this is unreasonable: both because in such substances there can be nothing violent, as we have proved; and because the violent and the unnatural, since they are accidental, cannot precede that which is according to nature, nor can they be consequent upon the whole species.

Further. Since everything naturally desires its own perfection, it is for matter to desire form and not vice versa. Now the soul is compared to the body as form to matter, as was shown above. Therefore the union of the soul and body answers to the desire not of the soul but rather of the body.

If, however, it be said that both are natural to the soul, namely union with the body and separation from the body, according to different times:—this is seemingly impossible. Because changes that occur naturally in a subject are accidental, such as youth and old age. Hence if union with and separation from the body are natural changes as regards the soul, union with the body will be an accident of the soul: and consequently the man resulting from this union will not be a per se but an accidental being.

Further. Whatever is subject to alteration according to a difference of time, is subject to the heavenly movement, which the whole course of time follows. Whereas intellectual and incorporeal substances, among which are separate souls, are above the whole order of bodies: wherefore they cannot be subject to heavenly movements. Therefore it is impossible for them that, according to a difference of time, they should be naturally, now united, now separated, or desire naturally this at one time, and that at another.

If, however, it be said that they are united to bodies neither by violence nor by nature, but by deliberate choice:—this is impossible. For no one wishes to come to a worse state except he be deceived. Now the separate soul is of a higher state than when united to the body; especially according- to the Platonists, who say that through being united to the body it forgets what it knew before and is balked in the pure contemplation of truth. Therefore it is not willingly united to the body except it be deceived. But there cannot be in the soul any cause of deception, since according to them it is supposed to have all knowledge. Nor can it be said that its judgment in a particular matter of choice, proceeding from its universal knowledge, is upset on account of the passions, as happens in the incontinent: because passions of this kind are not without a bodily alteration, so that they cannot be in the separate soul. It remains therefore that if the soul existed before the body, it would not be united to the body of its own will.

Further. Any effect resulting from the concurrence of two mutually independent wills, is a casual effect: for instance, when a person intent on buying meets his creditor on the market place without the latter having agreed with him to go there. Now the will of the begetter, on which the begetting of the body depends, is not dependent on the will of the separate soul which desires to be united. Since then the union of soul and body cannot take place without the concurrence of both wills, it follows that such union is casual: so that the begetting of a man is not from nature but from chance: which is clearly false, since it results in the majority of cases.

And again, if it be said that the soul is united to the body not from nature, nor of its own will, but by divine ordinance;—this also seems inadmissible, if souls were created before bodies. For God fashioned each thing according to a manner becoming its nature: hence it is said of each creature (Gen. i.) God seeing (Vulg.,—saw) that it was good, and of all together: God saw all things that He had made, and they were very good. Consequently, if He created souls separate from bodies, we must needs say that this manner of being is more becoming their nature. Now, it is not in keeping with the ordinance of the divine goodness to bring things down to a lower state, but rather to raise them to a better. Therefore it could not have been by divine ordinance that the soul was united to the body.

Further. It is not in keeping with the order of divine wisdom to raise up lower things to the detriment of higher. Now bodies that are subject to generation and corruption obtain the lowest place in the order of things. Therefore it was not becoming the order of divine wisdom to raise up human bodies by uniting pre-existing souls to them: since this could not be done without detriment to the latter, as proved from what has been said.

Origen took note of this, and since he maintained that human souls were created from the beginning, he said that they were united to bodies by divine ordinance, but as a punishment. For he was of opinion that they had sinned before bodies were formed, and that according to the gravity of their sin they were enclosed in bodies more or less noble as in so many prisons.

But this opinion cannot stand. Because punishment is something contrary to a good of nature, and for this reason is said to be evil. If, therefore, the union of soul and body is something penal, it is not a good of nature. Yet this is impossible: for it is intended by nature, since it is the end of natural generation. Moreover it would follow that to be a man is not good according to nature; whereas it is said (Gen. i. 31) after the creation of man: God saw all the things that He had made, and they were very good.

Further. Good does not result from evil except by accident. Consequently, if it was appointed that the soul should be united to the body on account of a sin of the separate soul, since this union is a good, it follows that it is accidental. Therefore it was by chance that man was made. But this is derogatory to divine wisdom, whereof it is said (Wis. xi. 21) that It ordered all things in number, weight, and measure.

This is also clearly opposed to the teaching of the Apostle. For it is said (Rom. ix. ii, 12) of Jacob and See reference on page 239.

Esau, that when they were not yet born, nor had done any good or evil... it was said that the elder shall serve the younger. Therefore, before this was said, their souls had not committed any sin: and yet this was said after their conception, as appears from Gen. xxv. 23.

When we were treating of the distinction of things, we adduced against the position of Origen several arguments, which may also be employed here. Wherefore, omitting them, let us pass on to others.

Again. We must admit that the human soul either needs the senses, or not. Now experience would seem to make it clear that it needs the senses: because whoever lacks a certain sense, has no knowledge of the sensibles that are known through that sense: thus one born blind has neither knowledge nor any understanding whatever of colours. Moreover if the soul need not the senses in order to understand, we should not find in man any relation between sensitive and intellective knowledge. Yet we observe the contrary; for sensation leads to memories, and these lead us to take observation of things, whereby we arrive at the understanding of the universal principles of sciences and arts. Accordingly, if the human soul needs the senses in order to understand; since nature fails no thing in what is necessary for the accomplishment of its proper operation,—thus it supplies with fitting organs of sense and movement those animals which are animated with the powers of sense and movement,—the human soul must not have been fashioned without the necessary assistance of the senses. But the senses are inoperative without corporeal organs, as shown above. Therefore the soul was not made without the organs of the body.

If, however, the human soul does not need the senses in order to understand, and for this reason is said to have been created apart from the body: we are compelled to say that before being united to the body, it understood by itself all scientific truths. In fact the Platonists granted this, when they held that ideas,—which in Plato’s opinion are the separate intelligible forms of things,—are the cause of knowledge: wherefore the separate soul, since there was no obstacle in the way, received full knowledge of all sciences. We must therefore say, since it is found to be ignorant when united to the body, that it forgets the knowledge it had previously. The Platonists grant this also, and allege as a proof of this that however ignorant a man may be, if he be questioned methodically about things that are taught in the sciences, he will answer the truth: thus if a man has forgotten some of the things which he knew before, and some one suggests to him consecutively the things which he has forgotten, he recalls them to his memory. Whence it also followed that to learn is nothing else than to remember. Accordingly it follows, as a necessary consequence of this opinion, that union with the body hinders the soul from understanding. Now nature does not unite a thing to that which causes an obstacle to its operation, rather does it unite it to that whereby its operation is rendered more prompt. Consequently the union of body and soul will not be natural: and so man will not be a natural thing, nor will his generation be natural: which statements are clearly false.

Further. The last end of anything is that which it strives to obtain by its operations. Now man by all his well ordered and right operations strives to attain the contemplation of truth; for the operations of the active powers are so many preparations and dispositions to the contemplative powers. Therefore the end of man is to arrive at the contemplation of truth. For this purpose, then, was the soul united to the body, whereby a man comes into being. Therefore it is not through union with the body that the soul loses knowledge; on the contrary, it is united to the body that it may acquire knowledge.

Again. If a man who is ignorant of the sciences be questioned about matters pertaining to the sciences, he will not answer the truth except as regards universal principles which no one ignores, since they are known to all in the same way and naturally. Afterwards however, if he be questioned consecutively, he will answer the truth about things closely connected with the principles, while bearing those principles in mind; and he will continue to do so, as long as he is able to apply the force of those principles to the matters on which he is questioned. From this, accordingly, it is clear that knowledge is caused anew in the person questioned by the first principles; and not by the remembrance of a knowledge he had possessed before.

Further. If the knowledge of conclusions were as natural to the soul as knowledge of principles, all would have the same opinion about conclusions as they have of principles: since things that are natural are the same for all. Now all have not the same opinion about conclusions, but only about principles. It is therefore clear that the knowledge of principles is natural to us, but not the knowledge of conclusions. Now from that which is natural to us we acquire that which is not natural: even as in external things we make with our hands all the products of art. Therefore we have no knowledge of conclusions save that which we obtain from principles.

Again. Forasmuch as nature is ever directed to one thing, it follows that of one power there is naturally one object, for instance colour is the object of sight, sound of hearing. Wherefore the intellect, since it is one power, has one natural object, of which it has knowledge per se and naturally. And this object must be that under which are comprised all things known by the intellect: just as under colour are comprised all colours, which are per se visible. Now this is no other than being. Therefore our intellect knows being naturally, and whatever is per se comprised under being as such; and on this knowledge is based the knowledge of first principles, such as the incompatibility of affirmation and negation, and the like. Consequently, these principles alone are known naturally by our intellect; while conclusions are known through them: even as through colour the sight knows both common and accidental sensibles.

Further. That which we acquire through the senses was not in the soul before (its union with) the body. Now, knowledge of principles is caused in us from sensibles: for had we not perceived some whole by our senses, we should be unable to understand that a whole is greater than its part: just as a man born blind is unable to have an idea of colours. Neither, therefore, had the soul any knowledge of principles before (its union with) the body: and much less, of other things. Consequently Plato’s proof of the existence of the soul before its union with the body cannot stand.

Again. If all souls existed before the bodies to which they are united, it would seem to follow that the same soul is united to different bodies according to the vicissitudes of time. In fact this is an evident consequence of the opinion of those who hold the eternity of the world. For, if men have been begotten from eternity, it follows that an infinite number of human bodies have been begotten and corrupted during the whole course of time. Therefore we must say either that an actually infinite number of souls pre-existed, if each soul is united to a single body, or—if the number of souls be finite—that the same soul is united at one time to this, at another time to that body. And the same would seem to follow if we suppose that souls existed before bodies, but that generation was not from eternity. For although it be supposed that the begetting of men has not always been, one cannot doubt that it can be of infinite duration: because each man is so formed by nature, that unless he be accidentally hindered, he is able to beget another even as he himself was begotten of another. Yet this is impossible if, supposing a finite number of souls, one soul cannot be united to several bodies. Wherefore several who have asserted the existence of souls before bodies, maintained the transmigration of souls. But this is impossible. Therefore souls did not exist before bodies.

That one soul cannot possibly be united to different bodies is proved thus. Human souls do not differ specifically from one another, but only numerically: else men also would differ in species from one another. Now numerical distinction arises from material principles. Consequently the distinction among human souls will have to be taken from something material. Not, however, as though matter were part of the soul: for it has been shown above that the soul is an intellectual substance and that no such substance has any matter. It remains, therefore, that in the manner indicated above the distinction and plurality of souls must be taken from their relation to the different matters to which souls are united. Consequently if there are different bodies, they must needs have different souls united to them. Therefore one is not united to several.

Again. It has been proved above that the soul is united to the body as its form. Now forms must be proportionate to their respective matters: since they are related the one to the other as potentiality to act: for the proper act corresponds to the proper potentiality. Therefore one soul is not united to several bodies.

Moreover. The power of the mover should be proportionate to its mobile: for not every power moves every movable. Now it cannot be said that the soul, even were it not the form of the body, is not its mover, for the animate differs from the inanimate by sense and movement. Therefore different souls must correspond to different bodies.

Again. In things subject to generation and corruption, the same identical thing cannot be reproduced by generation: for, since generation and corruption are movements towards substance, in things that are generated and corrupted, the substance does not remain the same, as it does in things that are moved locally. Now, if the one soul is united successively to various generated bodies, the same identical man will be reproduced by generation. This is a necessary consequence for Plato, who said that man is a soul clad with a body. It follows also for all the others: because, since the unity, even as the being, of a thing follows its form, it follows that those things are one in number, whose form is one in number. Therefore it is not possible for one soul to be united to several bodies: and from this it follows also that neither were souls before bodies.

The Catholic faith declares itself in agreement with this truth. For it is said in the psalm He Who hath made the hearts of every one of them: because, to wit, God fashioned a soul for each one separately, and neither created them all together, nor united one to different bodies. Hence it is also declared in the book De Ecclesiasticis Dogmatibus We affirm that the souls of men were not created from the beginning together with other intellectual natures, nor all at the same time, as Origen pretended.