Proposition 26

187. Every substance that stands in and of itself does not fall under corruption.

188. But if someone says: it is possible that a substance which stands in and of itself fall under corruption, we say: if it is possible that a substance that stands in and of itself falls under corruption, it is possible that it be separated from its essence and be fixed, subsisting through its own essence without its own essence. And this is inappropriate and impossible since, because it is one, simple, non-composite, it itself is cause and that which is caused at the same time. But every corruption of that which falls under corruption takes place only because of its separation from its cause; but while a thing persists depending on its own cause which conserves and preserves it, it does not perish nor is it destroyed. Thus if it is such, the cause of a substance which stands through its own essence is not ever separated, since it is inseparable from its essence, because its cause is itself in its own formation.

189. And it is only its own cause because of its relation to its cause; and that relation is its formation. And therefore, because it is always related to its cause and it is the cause of that relation, it is the cause of itself according to the mode which we have said, that it does not perish nor is it destroyed, since it is the cause and that which is caused at the same time, as we have recently shown.

190. Now therefore it has been verified that every substance standing through itself is neither destroyed nor corrupted.

411. Above (181) it was concerned with the ungenerable: here (187) it is concerned with the incorruptible and the corruptible:

and first, about the incorruptible;

second, about the corruptible, in proposition 27: every destructible substance (191).

412. About the first, a proposition like this is posited: every substance standing through its own self is not falling under corruption (187). Which indeed is posited in Proclus' book in proposition 46 under these words: every autohypostatic is incorruptible.

413. As evidence for this proposition, it should be considered that while the preposition 'per' denotes a cause, that is said to stand or subsist 'per se' which does not have cause of being except itself. Now, there is a two-fold cause of being, namely: the form through which something is in act and the agent which makes it to be in act. If, therefore, it be called standing through its own self which does not depend from a superior agent, thus to stand through its own self belongs to God alone who is the first agent cause from which all second causes depend, as is clear from the things said above (129).

Now, if it be called standing 'per se', that which is not formed by anything else, but itself is the form, thus being standing through its own self belongs to all immaterial substances. For substance, which is composed out of matter and form, is not standing through its own self except by a relation of parts, because, that is, matter is in act through form and form is sustained in matter; just as it is said that something is moving itself by a relation of parts, because one part of it is moving and another part of it is moved. Thus therefore it is clear that to stand through its own self can only belong to a substance that is form without matter.

414. Now a substance of this kind, by necessity, is incorruptible (188): for it is manifest in corruptible things that corruption happens because something is separated from its formal cause through which something has being in act: for just as generation, which is a way to being, is by acquisition of a form, so corruption, which is the way to non-being, is by the loss of a form. Therefore, if a substance standing through its own essence be corrupted, it would be necessary that it be separated from its own formal cause; therefore it would be separated from its essence; which is impossible. Therefore, it is not possible that a substance standing through its own self be corrupted.

415. But lest anyone believe that substances of this kind, standing through their own essence, might not depend on some superior agent cause, he excludes this consequently, there: and a cause is not made (189), and he says that this is not to be understood that a substance of this kind be a cause of its own self, as if it did not depend on the superior agent cause. But this is said, because substance of this kind has through its own self a relation to the first cause, insofar as, namely, it is the cause of its formation; for we see that material things are referred to the first cause so that they accept being from it through their form and on that account substance, whose whole essence is form, has through itself the relation always to its cause and that relation is not caused in a substance of this kind through any other form. And hence it is that it is said to be a cause of itself by the aforesaid mode (185); and hence it is that it cannot be corrupted, as has been shown (188 [414]).

416. It appears, therefore, (190) that every substance standing through its own self is incorruptible.