Commentaria in Summam contra Gentiles, Liber II

There were also others, says Saint Thomas, who, erring more gravely, held the soul to be a body¹. Although their opinions were various, they are refuted against them by common arguments; then their motives are resolved².

I. As to the first, it is argued: and first³, thus. Living things are composed of soul and body. Therefore one of them is form and the other matter: because living things—namely the lower and composite ones—since they are natural things, are composed of matter and form. But the body cannot be form: since it is not in another as in matter and subject. Therefore the soul will be form. Therefore the soul is not a body. — The last consequence is evident. Because a body is not a form.

II. Concerning this proposition, Living things are composed of soul and body, a doubt is raised. For according to the doctrine of St. Thomas ⁴, since in one composite there is only one substantial form, just as living things have animated esse through the soul, so through that same soul they have corporeal esse. But the same thing is not composed of itself. Therefore living things are not composed of soul and body, since body includes soul.

2. To this one may reply in three ways. First, that living things are not composed of body and soul as of two parts really distinct; but only as of parts distinct according to reason, insofar as the account of the soul is one thing insofar as it is a soul, and another insofar as it is a bodily form.

But from this response it follows that the composition of a living thing from soul and body will be only a composition according to reason. The opposite of this Saint Thomas says in the Treatise on Being and Essence ⁵, where he sets out the difference between the composition of man from soul and body, and his composition from animal and rational, because man is said to be from body and soul as a certain third thing constituted from two things; but he is from animal and rational as a third intellect from two intellects.

3. On account of which, second, it can be answered that, taking the body insofar as it signifies a composite of matter and corporeal perfection precisely, and the soul as signifying vital perfection precisely, they are two parts really distinct; for it is accidental to the body taken precisely that its perfection be identical with the soul, since the soul prescinds from it per se. And therefore the composition of man from soul and body is real, as being from two parts really distinct.

But this response does not seem to be distinguished a priori from the first. For although the perfection of corporeity in inanimate things is really distinct from the soul, yet in an animate thing, say in Socrates, it is not really distinct from the soul, since the same numerical form gives Socrates both corporeal esse and animated esse. And although the ratio of body, as such, excludes the soul as soul—that is, the ratio of soul—nevertheless in Socrates the entity of the corporeal form does not exclude the entity of the soul. Nor does it happen accidentally that the entity of Socrates' corporeal form is really identical with the entity of the soul, since each thing is per se, not per accidens, identical with itself; though it can indeed be said that it happens to that corporeal form, considered precisely as grounding the ratio of corporeal form, that it is a soul, because the ratio of soul, as soul, is found outside the ratio of corporeal form, as such. But this precision of rationes in Socrates' form is only according to the consideration of the intellect, insofar as the intellect forms one concept of it as it is a corporeal form, and another as it is a soul: on the side of the thing, however, they are simply one thing. From this it is clear that, when corporeity is considered precisely in Socrates, and likewise the soul precisely, Socrates is not composed of soul and body as of two parts really distinct, but only as of two parts according to reason: since that precision of the corporeal form from the soul, and conversely, is not in the thing, but only in the consideration of the intellect. And so this response does not differ from the first. Consequently it is rejected by the same argument by which the first is rejected.

4. A third answer can be given, on the supposition that St. Thomas speaks not only according to the common opinion of those who take the body as a part entirely distinct from the soul, but also according to the truth: that by the name "body" St. Thomas understands matter existing under corporeal quantity. For this is really distinct from the soul, and it precedes it in the genus of material cause. For although quantity does not inhere in bare matter but in matter informed by the corporeal form, which in living things is not really distinct from the soul, nevertheless matter itself together with corporeal quantity, precisely so taken, is really distinct from the soul. And thus all living things are composed of body and soul as of two parts in reality.

5. It could also be answered, fourthly, as far as occurs to me for the present, that living things are composed of body and soul in the same way in which mixed bodies are said, according to the opinion of some, to be composed of the elements ⁶. For the elements are said to compose the mixture not because they remain in the mixture distinct in reality, but because from them, first really distinct and afterwards corrupted yet remaining in the mixture only as to one quality in which all are contained virtually, the mixture is composed. So proportionally we may say that, when the soul comes to matter previously informed by a corporeal form, the animate thing is composed of body and soul previously really distinct, but with the preexisting body afterwards corrupted by the advent of the soul, yet remaining in its like and virtually in the esse that the soul gives, inasmuch as the soul that supervenes gives a corporeal esse like that which the preceding form gave, and contains the corporeal form virtually. Hence, just as mixtures are said to be composed of the elements as of a matter substantially passing away but remaining virtually in one quality, so living things are said to be composed of soul and body: of the soul indeed as of a part substantially remaining, but of the body as of a part substantially passing away yet remaining in its like, or remaining virtually in the one esse that the soul gives to the matter. And therefore, just as we say that mixtures are really composed of the elements, notwithstanding that in the mixture they are corrupted and remain only virtually in the mixture, so we may say that living things are really composed of body and soul, even though the body to which the soul supervenes is corrupted, and remains in the living thing only virtually or also in its like.

III. Second. The soul is not separate from the body while it lives; therefore it is not a body. — The consequence is proved: because two bodies cannot exist at the same time in the same place.

Third. If it were a body, it would have something else containing it. And then that thing would rather be the soul, since we see that when the soul departs, the body dissolves. Then, if that containing thing is again a body or divisible, either one must arrive at something indivisible and incorporeal, which will be the soul, or there will be an infinite regress. The second is impossible. Therefore the first must be granted. — The first consequence is proved: because every body is divisible, and everything divisible needs something to contain and unite its parts.

IV. Fourth. The soul is a mover that is not moved. Therefore, etc. — The consequence is evident. For no body moves without itself being moved, as was shown above. — But the antecedent is proved: because it is the moving part of the animal; for the part of a self-mover that is the mover is a mover that is not moved.

2. In this argument three doubts arise. The first concerns the antecedent. For since in a self-mover there is only one substantial form, it follows that the body, which is the moved part of the animal, includes the soul. And consequently, when the body is moved, the soul is moved. Therefore the soul is not an unmoved mover.

The second doubt, arising from the same root, concerns that proposition, The soul is the moving part of the animal. For since the mover and the moved are not the same thing, if the soul is the mover, it follows that it does not belong to the moved part as its form. Therefore either prime matter alone will be the part moved in the animal, and not the body; or the body will not be a body through the soul, but through some other form. Both of these are false in the doctrine of St. Thomas ⁷.

The third is concerning that proposition, No body moves unless moved. For according to the doctrine of St. Thomas in the First Part, q. 66, a. 3, ad 2, the empyrean heaven has an influence upon the bodies that are moved. And yet it is itself immobile. Therefore some body moves without being moved.

3. To the first of these it is said that, although the soul is the form of the moved part of the animal, it is not nevertheless moved per se by the motion of that part, but only per accidens, namely by the motion of the body. Now St. Thomas intends this here, and it is Aristotle's teaching in Book VIII of the Physics ⁸, that the soul is a part that moves but is not itself moved per se insofar as it moves.

To the second objection it is answered, according to the teaching of St. Thomas in Qu. de Anima, a. 9, ad 6, that the soul of an animal is united to matter with respect to its esse, and acts and moves through its powers. Hence it is in one way the mover, and in another way the formal part of the thing moved. For it is the mover through its cognitive and appetitive power; but it is the formal part through its substance alone, giving esse to the matter. Whence it comes about that the composite of organ and power, especially the appetitive power, as is the heart, moves the other parts of the body as that which moves, while the soul does so as the first principle by which it moves; but the soul is moved, or is a part of the thing moved, insofar as it is united to matter with respect to esse. Now there is no inconsistency in the same thing being the first mover with respect to its substance, yet moving proximately through a power; and being a part of the thing moved insofar as it is united to matter with respect to esse.

To the third it is said, from the doctrine of Saint Thomas, Potentia, q. v, a. 8, as was said above in chapter XX of this second book⁹, that a body has a twofold action: one according to the property of the body; the other according as it reaches in some way to the order of the separate substances, as something participating in their mode. The first action is for the transmutation of matter from form to form; the second is for a certain diffusion of its likeness, just as color acts upon its likeness in the medium and in the sense. By this action the empyrean heaven acts upon lower bodies, but not by the first. Hence in the First Part, where above, it is said that it does not act by something passing and arriving through motion, that is, through the transmutation of matter from form to form, but by something fixed and stable, namely a power of containing and causing. — Now the proposition of Saint Thomas is understood of the first motion, not of the second. Hence there is no contradiction.

V. Fifth. Understanding is an act of the soul, not of the body. Therefore the soul, at least the intellective soul, is not a body.

VI. As to the second point, the arguments against the conclusion are resolved¹⁰. For certain people argued that the soul is a body: first, because the son is made like the father even in the accidents of the soul, and yet he is generated by a bodily separation.

Then because the soul suffers along with the body.

Then because it is separated from the body. For the separation of bodies is their touching one another.

2. To all of these it is answered by denying the consequence. And to the first it is said that such a likeness exists because the complexion of the body is in some way the cause of the passions of the soul, in the manner of something disposing. And therefore, where there are like complexions—namely, on account of the efficacy of the generative power—there are frequently like passions of the soul.

To the second it is said that the soul suffers with the body only per accidens, because it is its form: for when the whole suffers, the soul, which is its formal part, must also suffer.

To the third it is said first, that the soul is not separated from the body as the touching thing from touch, but as form from matter. — It is said second, that there is also some touch of the incorporeal to the body, namely according to power, as is clear from what was said above.

3. From these things it is clear that those erred who, unable to transcend the imagination, said that what is not a body is not. In whose person, as of fools, it is said Wisdom 2: Smoke and breath are in our nostrils etc.