Chapter 91 — That there are some intellectual substances which are not united to bodies

It may be shown from the foregoing that there are some intellectual substances which are in no way united to bodies.

For it has been proved above (Ch. 79.) that when the body perishes, the substance of the intellect remains inasmuch as it is everlasting. And if the substance of the intellect which remains be one in all, as some assert, (Cf. ch. 80.) it follows of necessity that it is, in its being, separate from the body. And thus our point is proved, namely, that some intellectual substance subsists apart from a body. If, however, many intellectual souls survive the destruction of bodies, it will be competent to some intellectual substances to subsist apart from a body: especially since it has been proved (Ch. 83.) that souls do not pass from one body to another. Now this separation from bodies is accidentally competent to souls, since they are naturally forms of bodies. But that which is accidental must be preceded by that which is essential. (Aristotle, Physics 8.5, 256b3–12.) Therefore, there are some intellectual substances, naturally prior to souls, to which it is essentially competent to subsist apart from a body.

Moreover. Whatever belongs to the generic nature must belong to the specific nature: whereas certain things belong to the specific nature which are not in the generic nature. Thus “rational” belongs to the essence of man, but not to the essence of animal. Now that which belongs to the specific nature and not to the generic nature does not of necessity belong to every species of the genus: for there are many species of irrational animals. And it belongs to the intellectual substance, by reason of its genus, to be essentially subsistent, since it has an essential operation, as we have shown above. (Ch. 51.) Now it belongs to the nature of an essentially subsistent thing not to be united to another. Therefore, it does not belong to the nature of an intellectual substance to be united to another, although it does belong to the nature of some intellectual substance (namely, the soul). Therefore, there are some intellectual substances that are not united to a body.

Again. The higher nature in its lowest degree touches the lower nature in its highest degree. (Pseudo-Dionysius, On the Divine Names, ch. 7.) Now the intellectual nature is higher than the corporeal: and it touches it in respect of one of its parts, namely the intellective soul. Therefore, it follows that, just as the body that is perfected by the intellective soul is the highest in the genus of bodies, so the intellective soul that is united to a body is the lowest in the genus of intellectual substances. Therefore, there are some intellectual substances not united to bodies which, in the order of nature, are higher than the soul.

Again. If, in a genus, there be something imperfect, we find that there is something above it which in the order of nature is perfect in that genus. (Cf. Aristotle, Metaphysics 12.7, 1072b30–1073a4.) Now forms that are in matter are imperfect acts, since they have not complete being. Therefore, there are some forms that are complete acts, subsistent in themselves, and having a complete species. But every form that subsists in itself without matter is an intellectual substance, since immunity from matter gives intellectual being, as was shown above. (Ch. 82.) Therefore, there are some intellectual substances that are not united to bodies: for every body is material.

Moreover. Substance can be without quantity, although there cannot be quantity apart from substance: because substance precedes the other genera in time, idea, and knowledge. (Aristotle, Metaphysics 6.1, 1026a10–22.) But no corporeal substance is without quantity. Therefore, there can be some things in the genus of substance that are altogether without a body. Now all possible natures are found in the order of things: otherwise the universe would be imperfect. Moreover, in everlasting things there is no difference between actual and possible being. (Aristotle, Physics 3.4, 203b28–29.) Therefore, there are some substances subsistent apart from a body, below the first substance, which is God (who is in no genus, as we proved above), (Bk. 1, ch. 25.) and above the soul which is united to a body.

Further. If we find a thing composed of two, and one of these, which is the less perfect, be found to exist by itself, the one which is more perfect and less dependent on the other is also to be found by itself. (Bk. 1, ch. 13.) Now a certain substance is found to be composed of an intellectual substance and a body, as shown above. (Ch. 68.) And a body is found existing by itself, as evidenced in all inordinate bodies. Much more, therefore, are some intellectual substances found existing without being united to bodies.

Again. The substance of a thing should be proportionate to its operation, because operation is the act and the good of the operator’s substance. Now understanding is the proper operation of an intellectual substance. Therefore, an intellectual substance should be such as is competent to exercise the aforesaid operation. But since understanding is an operation that is not exercised by means of a corporeal organ, it does not need the body except insofar as intelligible objects are taken from sensibles. Yet this is an imperfect way of understanding, since the perfect way of understanding is to understand things that are intelligible by their nature. That only those things be understood which are not intelligible in themselves, but are rendered intelligible by the intellect, is an imperfect way of understanding. Therefore, if before every imperfect thing there must be something perfect in the same genus, (See above.) it follows that above human souls, which understand by receiving from phantasms, there are some intellectual substances which understand things that are intelligible in themselves, without receiving knowledge from sensibles, and for this reason are by their nature altogether separate from bodies.

Further. Aristotle argues (Aristotle, Metaphysics 12.8, 1073a22–b2.) as follows. A movement that is continuous, regular, and unfailing in itself must be from a mover which is not moved, neither essentially nor accidentally, as we have proved above. (Bk. 1, ch. 20.) Also, several movements must proceed from several movers. Now the movement of the heaven is continuous, regular, and so far as it is concerned, unfailing: and besides the first movement, there are many such movements in the heaven, as is proved by the observations of astronomers. Hence there must be several movers who are not moved, neither essentially nor accidentally. But no body moves unless itself be moved, as we proved above. (Bk. 1, ch. 20.) Moreover, an incorporeal mover united to a body is moved accidentally according as the body is moved, as instanced by the soul. Therefore, there must be several movers that are neither bodies nor united to bodies. Now the heavenly movements proceed from an intellect, as was shown above. (Bk. 1, ch. 20; cf. bk. 2, ch. 70.) Therefore, there are several intellectual substances that are not united to bodies.

This agrees with the opinion of Dionysius who says, in speaking of the angels, that they are understood to be immaterial and incorporeal. (Pseudo-Dionysius, On the Divine Names, ch. 4.)

By this is refuted the error of the Sadducees who said that there is no spirit (Acts 23:8); as also the assertion of the philosophers of old who said that every substance is corporeal; (Cf. bk. 1, ch. 20.) and the opinion of Origen who said that (with the exception of the divine Trinity) no substance can subsist apart from a body; and of all those others who hold that all the angels, both good and bad, have bodies naturally united to them. (Cf. the preceding chapter.)