Cursus Philosophicus Thomisticus, Secunda Pars Philosophiae Naturalis

As we resolved from Aristotle in Physics III, q. 14,¹ and Physics V, q. 19, aa. 1 and 2,² motion, as distinct from change taken generally, requires two conditions. The first concerns the subject: its subject must be a being in act, that is, informed by a substantial form, and not a being in potency, which is prime matter, although prime matter suffices for change. The second concerns the terms: motion properly so called must be between positive terms and, consequently, between proper or positive contraries. For change, however, a privative opposition from nonbeing to being or the reverse suffices in a subject capable of both. From this it is clear that corruption is not motion strictly so called, as distinguished from change, because it is not between positive terms but proceeds from being to nonbeing.

There is, however, a doubt on two points. First, does corruption lose the character of substantial change because its terminating term is the cessation of a form, so that it is merely the privation of generation? Second, does it differ from annihilation because it occurs in a subject capable of both, whereas a thing in annihilation ceases altogether into nothing? Hence it will remain in doubt whether both annihilation and corruption are changes. Here we speak of corruption in the character of change; in the next article we shall treat it in the character of an action, asking whether generation and corruption are the same action or how they are connected with one another.

Some therefore hold that corruption is not a real change, but only a privation of the action and concurrence by which the preceding form was preserved. Corruption is opposed to generation not because it produces something, but because it destroys; therefore it is privative and does not imply a real change. Indeed, it does not imply identity of action with generation, but only connection and linkage: just as the introduction of one form is followed by the removal of another, so generation being posited is followed by corruption. Thus they are consequent upon one another, not identical. And this is not always so, for generation can sometimes occur without corruption, if no positive form to be corrupted is presupposed in matter. The reason is that corruption tends toward negation, that is, toward nonbeing; therefore it is not a positive but a negative change, since a change is named from its terminating term.

The other view takes the opposite extreme: corruption is a positive change, and annihilation too is a positive change, since annihilation requires infinite power just as creation does. Therefore annihilation itself is some positive change or operation, since it is grounded in a positive power.

Nevertheless, I say first: Corruption is essentially and formally a change distinct from generation.

I say “essentially” and “formally” because I presuppose that generation itself, to which corruption is opposed, is a change not only radically but also formally, as was proved in the preceding question, art. 1. If corruption is a change, since it is formally opposed to generation, it too will formally be a change, just as generation is. This is even more evident in corruption than in generation, because corruption necessarily requires the form to be corrupted to precede as its starting term; it cannot precede merely by priority of nature, since corruption makes the form cease to be. Nothing ceases unless it first exists, because ceasing is a passage from being to nonbeing. Nothing exists except in some duration, not merely by priority of nature, which is not a priority of existence but of signification, formality, and causality: through it, one thing is signified as depending on another and as coordinated with it under this formal aspect rather than another. Generation, however, proceeds from nonbeing to being and does not presuppose any duration of its starting term. Thus, for generation to have the character of change, it suffices that privation precede by priority of nature. It is enough that some subject, by its own nature, lack a form while having the capacity for it, so that it requires an action to acquire that form and consequently an action that regards the form as the terminating term of the acquisition. It must therefore regard some starting term, namely privation—not a privation that exists or affects the subject at that instant, but one that is then being expelled and not allowed to follow upon the subject’s nature. For the starting term to have that character, it suffices that at the instant it be in the process of being expelled from the subject, not that it exist there. Consequently, change is verified: the subject is otherwise at this present moment of time than it was before by priority of nature.

That corruption is a change distinct from generation is expressly asserted by St. Thomas, On Truth, q. 28, aa. 1³ and 6,⁴ and is drawn from the Philosopher, Physics V, ch. 1,⁵ lecture 2 in St. Thomas’s commentary,⁶ where he distinguishes as two changes the one from subject to non-subject—which is corruption—and the one from non-subject to subject—which is generation. What proceeds from subject to subject is motion, because it occurs between contraries, not contradictories. “Change from subject to subject,” or “from non-subject to subject,” is said by “subject” to mean not the supposit or substance itself, but being or nonbeing, that is, affirmation or nonaffirmation, as St. Thomas explains in the cited q. 28, a. 1.⁷

The reason is that something is changed not only when it acquires a form, but also when it loses one. Indeed, change is most evident when a form is lost, as when air loses light or a body loses whiteness, because then it is true that the thing is otherwise now than it was before. That corruption is a change distinct from generation is clear because they regard distinct terms, both the terminating term and the starting term. Since change consists in a passage from one thing to another, where the starting and terminating terms are distinct, the passage is distinct and consequently the change is distinct. But corruption passes from the being of a form to its nonbeing, while generation goes in the reverse direction, from the nonbeing of some form to its being. Therefore they imply distinct passages according to distinct starting and terminating terms.

That corruption is a real change is shown by distinguishing what is real as a positive thing from what is real in the sense of being found in reality, even though in reality it does not posit something but removes it. Thus we say that darkness and blindness are found in reality, because they are truly found there, not fictitiously. St. Thomas distinguishes corruption from generation as real in this second sense in the cited q. 28, a. 6.⁸

The reason is that, in this sense, the formal term itself or changed state of corruption is found and verified in reality—namely, the cessation of a form—because the form really is corrupted. Therefore the change itself, or its coming-to-be, is also found in reality. Yet it is not called a positive change, because its term is not positive; therefore the change itself cannot be positive either. For what is not positive in itself, such as the nonbeing of a form, does not come to be or pass away positively.

You will say: Through corruption not only something negative results as its term, namely privation of the form, but also something positive: the form remains in the potency of matter with respect to a supernatural agent, whereas before it was in act. Therefore some positive change is found in matter, namely a new mode of potentiality and an ordering toward a different agent.

We reply that matter itself receives nothing positive through the removal of the form that it did not have before, because even before it had an ordering toward the form as something to be drawn out once by a natural agent and many times by a supernatural agent. Thus, once the form has been drawn out and matter changed through it, the relation to the natural agent ceases, so that the agent can no longer draw it out—not because matter’s potency has changed, but because an extrinsic natural agent is lacking. When the form is corrupted, no further change occurs in matter’s potency with respect to this relation of containing the form.

From the conclusion stated it follows that if, in the generation of something, there is no positive form to be corrupted, but only a privation to be removed—as when light destroys darkness—then corruption and generation are not two changes. Corruption does not find a form to destroy and make pass from being to nonbeing; it finds only privation on the side of the starting term, and this is not changed from one privation into another. A passage from nonbeing to nonbeing is not a change. Therefore there is only a change from privation to being, and the corruption of privation is no change other than the passage to being, which is generation. Thus it is commonly taught in the matter of justification that, if the guilt that is destroyed is only a privation in the soul, justification is a single change insofar as it posits grace and remits guilt. But if the guilt that is destroyed leaves behind something habitual in the positive mode, a turning toward the creature, then there are two changes: the removal of that guilt and the introduction of grace.

I say second: Corruption and annihilation differ on the side of the terminating term. Through annihilation a thing ceases altogether to be, both on the side of form and on the side of the subject. Therefore annihilation is not a change properly so called, just as creation is not, although it is signified by way of change.

This conclusion is clear, because annihilation is opposed to creation. Just as creation involves no concurrence on the part of a material cause, but only on the part of an efficient cause that gives the whole of being, both as to form and as to matter, so annihilation is not a cessation through the concurrence of some material cause, but through the mere removal and suspension of the divine concurrence that perfects and gives the whole of being. Since it does not occur in any subject, it is not a change. Hence the term of annihilation is said to be nothingness itself, in its entirety: not only because the thing that is corrupted ceases altogether, but also because no positive term is joined to it and newly produced into which the destruction of the thing might terminate. Rather, on the side of the terminating term there is purely nothing. This is what is foremost in annihilation: that it terminate in nothingness. However much something is destroyed, whether wholly or partially, if it does not terminate in nothingness but instead terminates in some positive term joined to it, it is not annihilation. For this reason bread is not annihilated in the Eucharist, although it is destroyed in its entirety and ceases to be; it does not cease into nothing, but into the body of Christ. Thus the bread is destroyed by conversion, not by annihilation.

The reason is that annihilation, as we said, occurs through the suspension of a concurrence that wholly preserves a thing in being. Therefore its character involves not only the total destruction of a thing, but also the failure to join and substitute for it any positive term into which the destruction might terminate. For positing that positive term requires an action and the positing of some influx that produces or reaches it. Therefore, if annihilation is the suspension of the entire concurrence, it excludes every positive term joined to it; otherwise something would cease not by way of annihilation, but through the force of producing another term incompatible with the thing destroyed. Thus annihilation requires both the destruction of the whole of being and cessation into nothing, without the positing of any added term, precisely because it occurs through the suspension of divine concurrence.

But you will say: God can annihilate a form without annihilating matter, and an accident without annihilating its subject. Therefore destruction of the whole of being is not essential to annihilation. For then, although the being of the form in act is destroyed, it remains in the potency of matter, as when it ceases to be through corruption.

We reply that this is not annihilation simply and in every respect, just as, conversely, the production by God of a form or accident alone is not simply creation, but concreation when it occurs together with matter. In the same way, the suspension of concurrence with respect to the form alone is not annihilation simply, but is reduced to annihilation as one aspect of it, and because it has the mode of annihilation: it occurs through the suspension of concurrence without another form succeeding it, and it terminates in nothingness. That concurrence preserves the thing in total dependence and subordination to God; therefore its suspension is called annihilation, although it removes only part of the thing’s entity. The fact that it remains in the potency of its subject—not with respect to a natural agent, but with respect to divine power—does not prove that this occurs through a positive action. For its remaining in the potency of matter is not the term or effect of that suspension of concurrence; it was already present in matter by matter’s own nature. Since it is not destroyed by the suspension of concurrence, the thing is not annihilated in every respect, both as it is in act and as it is in the potency of its subject.

From these points you will gather that some are wrong to affirm that a creature can bring about annihilation through divine power, on the grounds that less power is required to destroy than to produce—for it is easier to destroy than to build—and thus that destruction involves no contradiction when performed by a creature, since it posits no entity but removes one.

Nevertheless, St. Thomas holds the contrary in Summa Theologiae III, q. 13, a. 1, where he also speaks of an instrumental cause and denies that one can be given for annihilation. The reason is clear: although destroying something by positing a form or disposition incompatible with it is easier than building, because the destructive form or disposition is more easily posited and produced, destroying something by suspending the concurrence of a cause belongs only to the cause that provides that concurrence. Since the concurrence suspended in annihilation proceeds from God himself, its suspension cannot belong to any created cause, but only to God. When secondary causes corrupt something, God’s concurrence with the corrupted form is also removed—not because creatures bring about this suspension, but because they produce a form incompatible with it, an action to which God also concurs; by concurring in that action, he ceases to concur with the opposite form. We shall speak of this in the next article.

To the reason for doubting proposed on behalf of the contrary view,⁹ we reply from what has been said that corruption is not mere privation, but a change consequent upon generation and terminating at the privation of a form, for it is a passage from being to nonbeing. Thus the argument proves that it is not a positive real change—that is, one that posits something on the side of its term—but a real destructive or privative change. It is called real because it is found in reality, not because it posits something positive in reality.