Summa summae S. Thomae sive compendium theologiae

¹

[Three kinds of union are distinguished. Accidental union is when, from two united substances, no new essence arises, nor does a communicability of actions result. Thus a garment with which a man is clothed is united to him. — Personal union is a union in which, between the substances that are united, there is a unity and communicability of actions, insofar as the actions of either substance, as of a principle quo, are also of the other, as of a principle quod, namely of the suppositum, in which each subject is united. Thus in Christ there are divine actions and human actions, according as they proceed from either nature as a principle quo, yet all of them pertain, as to a principle quod, to the person of Christ, God and man at once. — Essential union is had when, from two united substances, there arises not only a unity and communicability of action, but also a specific unity of nature in which the united substances exist.]

I say 1°: The union of the soul with the body is not accidental.

This is against Plato, who held that the pre-existing soul is united extrinsically to the body, in much the same way that a sailor is united to a ship, that is, accidentally. This opinion, which D. de Bonald seems to follow when he defines man as « an intelligence using bodily organs, » is not true. For by the common sense of men it is held that man essentially consists of a rational soul and an organic body, as of physical principles essentially required for constituting his specific nature. Hence the union between our soul and our body is more intimate.

I say 2°: The union of the human soul with the body is personal.

Proof. As consciousness evidently testifies, manifold

actions, whether corporeal, as sitting, or vegetative, as digestion and nutrition, or sensitive, as seeing and imagining, or intellective, as knowing and willing, are of one and the same principle quod, namely of the whole man, although those actions belong to man from a different principle quo, as falling from the body, and understanding from the soul. But the unity and communicability of actions arising from united substances is a sign of personal union. Therefore the union of soul and body in man is a personal union.

I say 3°: The union of the human soul with the body is also essential.

Proof. As we have already noted, by the common sense of men, if we wish to define man physically and essentially, we do not say that man is a rational soul, nor that he is an organic body, but that he is composed of a rational soul and an organic body. That is to say, from the rational soul and the organic body there results one specific substantial nature (for soul and body are substances, not accidents), which is man himself, from whom, if either the one or the other be withdrawn, he himself is destroyed. But things that are united in this way are united by essential union. Therefore the union of the human soul with the body is not only a personal union, but also an essential union.

St. Thomas has summed up both of the preceding conclusions in a few words, p. 3ª, q. 2, a. 1, ad 2, where he says: « From soul and body there is constituted in each of us a twofold unity, of nature and of person. Of nature indeed, according as the soul is united to the body, formally perfecting it, so that from the two there comes to be one nature, as from act and potency, or matter and form... The unity of person, however, is constituted from these insofar as there is some one [namely, man], subsisting in flesh and soul. »

It is confirmed. In the Athanasian Creed open mention is made of this twofold union, personal and essential. For it is said of Christ: « Perfect God [the divine nature], perfect man [the human nature], subsisting of a rational soul and human flesh. » These latter words express the essential union of the human nature. Moreover:

« As the rational soul and flesh are one man (behold, a person in a simple man), so God and man are one Christ (not by unity of nature, but by unity of the divine person). »

I say 4°: The human soul is the substantial form of the human body.

Although this conclusion is to be deduced from the preceding ones as a necessary corollary, it must be demonstrated singly and explicitly, so that the nature of the union of the soul with the body in man may be perfectly known.

Proof. 1°. It is of faith. Thus the Council of Vienne defines, Clement. unica, de summa Trinit., § Porro: « We reprobate, with the aforesaid sacred council approving, as erroneous and hostile to the catholic faith, every doctrine or position rashly asserting, or calling into doubt, that the substance of the rational or intellective soul is not truly and of itself the form of the human body: defining, that the sincere truth of the faith may be known to all, and that access be closed off to all errors lest they creep in, that whoever shall henceforth presume to assert, defend, or pertinaciously hold that the rational or intellective soul is not the form of the human body of itself and essentially, is to be judged a heretic. » Here the council defines of every human soul what it had before pronounced of the soul of Christ, in these words: « Firmly adhering to the foundation of the catholic faith, besides which, as the Apostle witnesses, no one can lay another, we openly confess with holy mother Church that the only-begotten Son of God — subsisting eternally together with the Father in all those things in which God the Father exists — assumed in time, in the virginal chamber, unto the unity of his hypostasis and person, the parts of our nature united together, from which he himself, existing in himself true God, was made true man: namely, a passible human body, and an intellective or rational soul truly informing that body of itself and essentially. » But since opinions contradicting this definition afterward arose, the Fifth Lateran Council judged that this should be renewed. In the constitution Apostolici regiminis, promulgated in the eighth session, it is read: « Since in our days not a few have dared

to say concerning the nature of the rational soul, that it is mortal, or one in number in all men, and certain persons, philosophizing rashly, assert that this is true, at least according to philosophy — we, with the sacred council approving, condemn and reprobate all who assert that the intellective soul is mortal, or one in number in all men, and who call these things into doubt, since that soul is not only truly, of itself and essentially, the form of the human body — as is contained in the canon of Pope Clement V, issued in the general Council of Vienne — but is also immortal, and, in respect of the multitude of bodies into which it is infused, is singularly multipliable, and has been multiplied, and is to be multiplied. »

This doctrine was most recently confirmed by Pius IX in the Brief addressed to the Archbishop of Cologne on June 15, 1857, against the writings of Günther, who taught that there are two distinct souls in man, one sensitive and the other intellective: « We know, says the Pontiff, that the catholic opinion and doctrine concerning man is injured in those same books — that man is completed by body and soul in such a way that the soul, and that a rational one, is the true, per se and immediate form of the body. » But since Baltzer, professor at the University of Breslau, had attempted to revive the Güntherian doctrine, thus refuted, the aforesaid Pontiff wrote to the bishop of that same city on April 30, 1860: « This indeed we cannot but vehemently disapprove, considering that this opinion, which posits one principle of life in man, namely the rational soul, from which the body also receives motion and all life and sense, is most common in the Church of God, and appears so joined with the dogma of the Church by most doctors — and indeed by the most approved ones especially — that it is the legitimate and only true interpretation of it, and therefore cannot be denied without error in faith. »

Proof. 2°, by an easy and evident argument borrowed from St. Thomas, II Contra gent., c. 68: « For something to be the substantial form of another, two things are required. One of these is that the form be a principle of being substantially to that of which it is the form: and I call it a principle, not effective, but formal, by which something is and is denominated a being. Whence it follows

another thing, namely, that the form and the matter agree in one act of being, which does not happen with an effective principle in relation to that to which it gives being; and this act of being is that in which the composite substance subsists, which is one according to being, consisting of matter and form. » This major of the argument is the very definition of substantial form. But our human soul is a principle of being substantially to our body, which is not essentially human except from the human soul, and soul and body subsist in a unity — not only personal, but essential and specific — of man. Therefore the human soul is united to our body as its true substantial form.

The Angelic Doctor, hic q. 76, a. 1, o, sets forth another demonstration, drawn from consciousness, by which we know with certainty that the vital operations which we notice in ourselves come from the soul: « It must be said that the intellect, which is the principle of intellectual operation, is the form of the human body. For that by which something first operates is the form of that to which the operation is attributed: as that by which the body is first healed is health, and that by which the soul first knows is knowledge; whence health is the form of the body, and knowledge is in a certain way the form of the soul. And the reason for this is that nothing acts except according as it is in act. Whence, that by which something is in act is that by which it acts. Now it is manifest that the first thing by which the body lives is the soul. And since life is manifested according to diverse operations in the diverse grades of living things, that by which we first perform each of these works of life is the soul. For the soul is the first thing by which we are nourished, and sense, and are moved according to place, and likewise that by which we first understand. This principle, therefore, by which we first understand — whether it be called the intellect, or the intellective soul — is the form of the body. And this is the demonstration of Aristotle in book II de Anima. But if anyone should wish to say that the intellective soul is not the form of the body, he must find a way in which this action, which is to understand, is the action of this man². » Now no one will be able to find another way.]