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.

These two difficulties are connected, and the resolution of one depends on the resolution of the other.

Regarding the first, the doubt is whether corruption is in any way an action, at least secondarily, or whether it has no place at all in the character of action, and how it is distinguished from generative action.

On this the authors hold various views. Some deny that generative action in any way, as an action, terminates in the corruption of a form. For wherever the touch of an action reaches—whether primarily or secondarily—it is an act of efficiency. But everything that efficiency touches, it touches by giving being; where it does not give being but removes it, it ceases to touch. Therefore corruption occurs through the very suspension of concurrence or through an omission, not through a secondary touch of action.

Others think that efficiency or action touches corruption secondarily, at least under a distinct formal aspect. On this one may consult Master Báñez on On Generation and Corruption I, ch. 3, explaining the axiom “the generation of one thing is the corruption of another,” where he also cites Cajetan. The reason is that generation and corruption are one motion, although it includes two changes, as is clear from the passages cited in the preceding article; therefore they are one action. Also, if suspension of concurrence alone occurs, it does not corrupt but annihilates; when it is joined to or follows upon an action, it belongs at least secondarily to that action. Producing a term belongs no more to an action than removing its opposite. Just as being corrupted is truly undergoing and truly changing, so corrupting and destroying is truly acting, at least secondarily.

The two views seem to be reconciled by saying that corruption is not formally an action, even mediately, but virtually. An action can be understood to touch a term mediately in two ways. First, it may touch one term principally and, by continuing the same influx or account of acting, touch another as less principal and contained under the first—as when some nature is produced principally and immediately, while its proper attribute is produced mediately, though by mediation of the same influx and causality. Second, once the principal term has been produced, the active influx ceases; but through the formal causality or informing by the produced form, another form incompatible with it is expelled or removed. In this way, someone who makes a thing incompatible with another is said effectively to corrupt the other through virtual, not actual, efficiency: that is, through the term whose informing expels and corrupts the other form as a secondary formal effect.

We say, therefore, that corruption is not an action in the first way but in the second. Once a form has been produced, the action no longer flows onward to corrupt; no influx can be understood, since with respect to the form to be corrupted it gives nothing but removes it. Therefore a positive influx is not continued, because no further positive term is given, and an influx is not necessary for negation. But once the form that is the term of the action has been posited, it is said to contain the action virtually, namely, terminatively. This involves the incompatibility of the opposite form, because it has the privation of that form joined to it. Thus it touches and expels the opposite form not through efficiency, but through the incompatibility arising from the form’s effectivity—that is, from the effected form that terminates the efficiency.

This resolution follows from St. Thomas, Sentences II, dist. 34, q. 1, a. 2, ad 5,¹ where he says: “What corrupts and generates does not generate and corrupt by the same aspect. It generates by introducing its own form; it corrupts because its own form is necessarily joined to the privation of another form.” St. Thomas does not place corruption in the action’s influx, but in the very addition of the form that has privation joined to it. Therefore corruption should not be reduced to the mere suspension of the concurrence preserving the opposite form, but to the action that produces a form incompatible with it; once that incompatibility is posited, concurrence ceases by its force. In this way the unity of action or motion is also preserved because the positive term is one, while there are two changes through the force of that efficiency, because two terms are touched: one by acting, the other by destroying, as explained.

Regarding the second difficulty—how these two changes, generation and corruption, are ordered so that the generation of one thing is called the corruption of another—some think that the changes are ordered only consecutively and successively, not identically in the same action or motion. But St. Thomas clearly says in On Truth, q. 28, a. 6, at the end,² “the generation of one thing is called by the Philosopher the corruption of another by concomitance, because they necessarily occur together, or because of the unity of motion, since motion terminates at these two changes.” Here “motion” means an action having this twofold change. And in Summa Theologiae I–II, q. 113, a. 6, ad 2, he says “that the infusion of grace and the remission of guilt are the same in the substance of the act.” He compares generation and corruption in the same way. He therefore holds that they are identified in the character of action.

Therefore, when the generation of one thing has the corruption of another joined to it, it is called the corruption of that other thing for two reasons:

First, because of the succession and order of forms following upon one another, since the forms are incompatible and, as one enters, the other departs. In that case the generation of one thing is the corruption of another causally, because corruption is connected with and follows upon generation.

Second, in a stricter sense, the generation of one thing is called the corruption of another not only because of the succession of forms and changes, but because of the unity of action or motion. Corruption is not an action distinct from generation; rather, the very same action that is formally generative is virtually corruptive by reason of the generated term, insofar as it is incompatible with the opposite form. In this incompatibility, the positive influx virtually remains, as terminated at the generated form, as was said.

In the conclusion we said “when generation has corruption attached to it” to indicate what we explained in the preceding article: corruption that is a true and real change occurs only when there is a positive form to be corrupted. For if only a privation to be removed by the generated form precedes—as when air in darkness is illuminated—the removal of that privation does not occur through a negative change distinct from the generation of light. Rather, the privation is corrupted through the very positive generation of light, without another change, since it is removed only through positive being, and therefore through generation, which is a passage or change from nonbeing to being, from privation to form. It is true that through our concepts we can distinguish in light the positive concept of making something luminous from the privative concept of removing darkness or the nonbeing of privation, because we take privation as a being of reason and therefore as something like being that is corrupted. In reality, however, that privation is nonbeing and is physically removed only through being. St. Thomas teaches all of this in On Truth, q. 28, a. 6, in the body of the article.³

Hence the objections that may be raised because generation sometimes occurs without corruption have no force. We admit that corruption is not essentially joined to every generation, but only to one to which a positive form to be corrupted is joined. If the form to be corrupted is partial, then the corruption is partial too, and the production is adgeneration. Nor did St. Thomas, in Sentences II, dist. 34, cited above,⁴⁵ say that generation and corruption differ only in reason. He said that the form of fire and the privation of air are the same in subject but differ in reason, which means that privation and form are not really distinct, since privation is not a real extreme. It does not mean, however, that generation and corruption themselves are not distinct changes in the way explained.

The objections are resolved.

First, it is argued: Corruption is privation, at least on the side of its terminating term, whereas generation is a positive action. Therefore they cannot be identified in any way, for true reality cannot be identified with what is nothing and a being of reason.

Second: By the same reasoning that proves generation and corruption to be identified in the character of motion and action, they should be identified in the character of change. For just as the same dispositional action and motion suffice primarily to introduce a form and secondarily to destroy its opposite, so one simple and single positive change will primarily be a passage to the generated form and secondarily a passage from the opposite form. For there is no contradiction in a negative change being identified with a positive one, just as a negative action, that is, destruction, is identified with positive generation.

Third, it is argued: If generation is identified with corruption, it will be true motion, which the Philosopher nevertheless denies in Physics V, ch. 1.⁶ The inference is clear: insofar as generation is identified with corruption, it has something positive as its starting term; and, by reason of itself, as generation, it has a positive terminating term. Therefore, at least identically, it is between two positive terms, a starting term and a terminating term, which is to be a motion at least identically.

Fourth: If generation and corruption are ordered to one another, this order must be founded on some causality or order of priority and posteriority of one with respect to the other. But there is no such order. Either they cause one another, which is impossible, since corruption, being privation, cannot have causality with respect to generation; or they do not cause one another, but one alone is cause and the other effect. This too is impossible: first, corruption cannot cause, as was said, and so it cannot itself be the cause with generation as its effect; moreover, corruption would then be intended per se and primarily, with generation as what follows. But if generation is the cause and corruption the effect, the generated form will be received before the opposite form is expelled, and thus the generated form will not be received in bare matter or on the supposition that the form has already been expelled.

Finally: If the generation of one thing is the corruption of another, they must be in the same instant. For if they occur at different times, they are not identified. But this cannot be, because corruption belongs on the side of the ultimate disposition, which removes the form incompatible with the generated form; and the ultimate disposition precedes the form in the very subject in which corruption occurs. Therefore corruption is not identified with generation.

To the first, we reply that the negation of another form can indeed be identified with some positive form. Privation and the negation of different things are not opposed; rather, such a negation is contained in and identified with the very form on which it is founded, just as faith has obscurity, heat has the privation of cold, and anything has the negation of what is distinct from it.

To the second, we deny that change and motion are subject to the same reasoning, insofar as motion signifies an action by way of influx. It is not impossible for one numerically identical action to reach several terms that are ordered or consequent upon one another, whether negative or positive, since an action can be virtually multiple and extend to many things, just as the power from which it proceeds can. Change, however, does not signify anything efficient, but a pure passage between terms; it signifies something effected rather than something effecting. Thus where there is a distinct passage between terms, there is a distinct change; but where there is an effect distinct even materially, there is not necessarily a distinct efficient action. What is material with respect to the character of action does not multiply that action, but it is formal with respect to the character of change and multiplies it, because the formality of change consists only in that effected passage, as was said.

To the third, we deny the inference. For it is not enough for the character of motion strictly so called, as distinguished from change, to have a positive starting term concomitantly and because of an attached incompatibility; it must have one formally and per se. But substantial generation is formally and per se not from a positive term, but from privation of the form. That it corrupts a preexisting substantial form is not because it has that form as its formal starting term. For it is per accidens and materially related to the form of fire that is generated that it be made from straw, paper, or wood; per se, however, it is made from what is not fire. Yet it corrupts whatever form preceded, because forms are incompatible in the same subject on account of the privation attached to them: each is a substantial form and consequently primary in the subject, so neither admits another as secondary. The preceding form is nevertheless not related as a formal starting term. It is a formal starting term when it contributes to constituting a positive distance or range between the starting and terminating terms. A positive range and distance between terms is constituted when the terms are positive and have a mean, so that the extremes contribute to such a range insofar as a mean is constituted from their proportion or combination, and per se require a passage from one form to another through that mean. Substantial forms, however, are not extremes from whose proportion or combination a mean is constituted, nor does a passage per se occur from one form to another through some mean. Rather, any form that is immediately receivable in matter is received if no contrary disposition stands in the way. Hence it is only by reason of a disposition that a passage through some intermediate form is required.

To the fourth, we reply that there is a mutual order of priority and posteriority between corruption and generation, as there is between the expelled form and the generated form. The expulsion of the corrupted form is prior in the order of material causality, while the generated form is prior in the order of formal causality. Hence St. Thomas says in On Truth, q. 28, a. 7,⁷ “the expulsion of the preceding form is naturally prior in the order of material causality. For every disposition toward a form is reduced to material causality, and stripping matter of a contrary form is a certain disposition for receiving the form.” He teaches that the introduction of the form is prior in the order of formal causality in Sentences IV, dist. 17, q. 1, a. 4, question 1,⁸ saying: “Removal of a form is naturally prior to the introduction of a form according to the order of material causality; but according to the order of formal causality, the reverse is true.” He says the same in Summa Theologiae I–II, q. 113, a. 8, ad 1: the agent acts through a form to remove its contrary, as the sun through its light acts to remove darkness. Therefore, on the sun’s part, to illumine is prior to removing darkness; on the air’s part, however, being cleared of darkness is naturally prior to receiving light, although both occur at the same time. Thus one should reason about corruption and generation as about the ultimate disposition and the form, as was said above.⁹ This priority on the side of material causality does not require priority in existence as well; it is enough that existence in reality accompanies it, while that priority explains only the formal aspect and function of the dependence and causality. Although corruption is a secondary effect of the generated form, as is the ultimate disposition, it can nevertheless have the character of a cause and priority in another order of causality and under another aspect, namely, insofar as it belongs on the side of the dispositive cause.

To the last, we reply that generation and corruption occur in the same instant of time, but under different priorities of nature. The ultimate disposition does not exist for any duration before the generated form, nor does it exist in the corrupted subject, although according to different priorities of nature it precedes and follows in the same generated subject, as was explained above;¹⁰ exactly the same must be said of corruption and generation.

We assume from Physics II, chapter 1,¹ that something is called natural because it has within itself the principle of its own motion, or because it proceeds from an intrinsic principle of nature; the intrinsic principles are matter and form. Things are called according to nature when they are accidents and affections fitting to nature, or when something is a subject whose being is from nature. Things that belong to something from an extrinsic principle belong to it either violently or preternaturally.

This, then, is what WE INQUIRE concerning corruption: whether it belongs to something by reason of an intrinsic principle and is therefore natural, or by reason of an extrinsic principle and is therefore violent and preternatural. A difficulty arises because, on the one hand, corruption has a principle that resists it, namely the very form and composite that corruption destroys; thus corruption cannot be natural to them but is violent, as destructive of them. On the other hand, matter is not per se and directly inclined to corruption, because corruption is an evil and nonbeing, and therefore is not the terminus of an appetite; consequently it is not a terminus of matter, since matter has a kind of appetite, and what is appetible to it is natural to it. Corruption, then, is not natural from either side.

From this arises a second difficulty: can corruption be intended per se by nature, given that it cannot be intended as an evil? Corruption is an evil, since it is a defect of nature; therefore it is beside nature’s intention, just as monsters are not intended by nature but deviate from it, being defects of nature. Nature always intends what is due to it, not what is alien and deviant.

Nevertheless, I say first: Corruption absolutely speaking is natural, and not violent to nature, by reason of matter insofar as matter signifies a corruptible nature; this takes “natural” as opposed to “violent.”

St. Thomas expressly maintains this conclusion in Summa theologiae I–II, q. 85, a. 6, and De malo, q. 5, a. 5.² Matter makes nature corruptible both because it has within itself privation together with aptitude and potentiality for several forms, none of which can fully satisfy matter—this is the disposition of a corruptible thing, as St. Thomas teaches in Summa theologiae I, q. 66, a. 2—and because matter admits composition from contraries, as is evident in all sublunary bodies. Every body composed of contraries is corruptible, since contraries act on one another and thus generate and corrupt, for generation and corruption arise from contraries. This, then, is how St. Thomas grounds the claim that corruption is natural, both in the passage just cited and in Sentences III, dist. 16, q. 1, a. 1.³ Matter is endowed with these conditions—potentiality for several forms, privation of some of them, and reception of contraries. Therefore it is natural for matter to admit the corruption of a form. Where the principle and root is natural, what belongs to something by reason of that principle must be natural, especially if this itself contributes to the common good, which cannot stand without the generation and corruption of things.

Nor is it an obstacle that what belongs only by reason of a passive principle does not seem natural, since its opposite is not violent; for something cannot suffer violence merely by reason of a passive principle, since that is not a principle that resists the agent. Nor does the inference “the root or principle is natural, therefore the act is natural” hold. One might object by appeal to free choice, which is naturally capable of sin because it comes from nothing, although sin is against nature—otherwise it would not be sin. Similarly, even if corruptibility itself is natural, it does not follow that corruption is not against nature. I say that these objections are not obstacles.

For the first, we said in Physics I, q. 9, a. 4,⁴ that a passive principle too is natural, as opposed to what is violent, and has an inclination toward something. If it is removed from that thing in such a way that nothing equally natural is substituted for it, it is said to suffer violence and has resistance to it—not active resistance, but formal resistance. That a passive principle suffices for the account of nature is taught by St. Thomas in Physics VIII, lecture 8,⁵ where he says that it is “against the Philosopher’s intention to posit an active principle in matter, as some say is necessary for there to be natural motion; for it suffices that the principle be passive, which is a natural potency for act.” Thus, if an obstacle wholly frustrates an inclination of this kind, it is violent to the passive principle. Some, however, are mistaken about matter’s appetite or inclination, which is for several forms: matter is adequately related to their whole collection, but inadequately to each one. Therefore, when one particular form is removed, matter is not subjected to violence in receiving another, since both are equally natural; the removal of one is not violent when another equally natural form takes its place. But if the corruption of forms and reception of others were wholly prevented, this would be violence to matter, since its natural tendency to several forms successively, with the corruption of the others, would be obstructed. Indeed, an argument follows from this: matter does not suffer violence by receiving one form and losing another precisely because it is in natural potency to all forms. Therefore, the removal of one is not violent and is thus natural; for, as the Philosopher says, every motion occurs either by nature or by force.⁶ Corruption is therefore natural to the passive principle insofar as it belongs to matter by its proper inclination to have several forms, not simultaneously but successively, losing one and acquiring another.

To the second objection we say that this inference does not hold for voluntary defects such as sins. The voluntary is opposed to the natural; thus, although the power to fail is natural because it comes from nothing, just as the will itself belongs naturally to a human being, its act is voluntary and free because the power is indifferent. Further, sins are against nature as rational, not as limited and coming from nothing. They are therefore said absolutely to be against nature because they oppose what is principal in nature, or what is proper to nature itself. Corruption, by contrast, is grounded in matter’s natural inclination to several forms and is natural in itself, neither violent nor voluntary. Again, although it is contrary to the form that is corrupted as regards its being, and likewise to the composite constituted by that form, on the other hand it is ordered to the common good, which is perpetuated and consists of several composites and things, one succeeding another through its corruption. Thus corruption is not contrary to matter itself insofar as matter depends on the whole collection of forms it can underlie; it is contrary only to the particular form it excludes. It is not connatural to matter to have being from only one form, but from many successively. The sin of the will, by contrast, is not ordered to a common good as the corruption of a form is; rather, it is universally and altogether disordered from such a good.

From this follows what we said in the passage cited in Physics I, q. 9,⁷ namely, that although corruption is contrary and violent to the form, and from this side corruption should not be called natural, nevertheless, because it is natural on the side of matter, it receives the denomination “natural” absolutely, not “violent.” The two accounts coexist because denomination always follows what predominates more in a given nature. In this case, what belongs on the side of matter predominates: not only is it natural and fitting to matter, as disposed toward one form, that another form be corrupted, but this also contributes to the common good of corruptible things, which are coordinated through the succession of generations and corruptions, and to the common appetite of matter itself insofar as that appetite extends to all forms. St. Thomas expressly teaches this in De malo, q. 1, a. 3, ad 18.⁸

TO THE DIFFICULTIES AT THE BEGINNING⁹ RAISED: To the first we reply that corruption has a principle that resists it on the side of form only with respect to the form’s particular being; but it has another connatural principle on the side of matter, insofar as matter by its nature seeks succession among forms. This itself is ordered to the common good of the whole order of corruptible things, and therefore corruption is denominated natural absolutely.

To the second we likewise say that corruption is an evil for a particular form, but a good for matter and for the common preservation of things. Still, it is one question how this corruption is natural and another how it is good and appetible: directly and primarily it is not good and appetible, since it is a privation. For it to be natural, however, it suffices that it follow from some intrinsic and natural principle, whether in accord with nature’s first inclination or in accord with a secondary inclination, as something required or annexed to it and ordered to it. For it to be good primarily and per se, a positive entity is required, as will be explained further at once.

I SAY, SECOND: Corruption is not intended by a particular agent insofar as it is a particular agent, either immediately or mediately, either by reason of itself or by reason of an attached order to the good; rather, with respect to that order, corruption is related per accidens. With respect to a universal agent, however, which orders and provides for the whole good of nature, such defects are within its intention—not primarily, but secondarily, given that order to the common good.

Not everyone agrees with the first part of the conclusion. Some hold that such evils and defects can be within the secondary intention of a particular nature and are not related to it wholly per accidens. St. Thomas seems to suggest this in Sentences IV, dist. 36, q. 1, a. 1, ad 2,¹⁰ although there he speaks of nature in itself and as extending universally to a particular or universal agent, as we shall explain shortly. He speaks in the same way in De veritate, q. 23, a. 2.¹¹

To understand the conclusion, however, we should note that in some evil or privation we can find three things. First, the good itself on which the evil or privation is founded, as a subject or as belonging to the side of the subject. Second, the evil itself formally, or the privation considered in itself. Third, some order to a good that follows from that privation—not per se, that is, insofar as it is an evil and defect, but insofar as it serves some good that cannot exist unless that evil intervenes. For example, there can be no acquisition and generation of the terminus toward which without corruption and the passing away of the terminus from which; nor can someone’s fortitude be shown unless another’s persecution is brought to bear.

IT IS THEREFORE CERTAIN that privation or evil itself cannot be intended per se and by reason of itself, because it lacks the formal character by which it could be intended, namely, goodness. For everything intended and desired must be intended as good and fitting. What lacks this formal character is therefore not intended in itself; if it is intended, it is through something else joined to it and clothing it. Hence it is intended not primarily and per se, but secondarily and per accidens. Still, what it has per accidens, or through something else, and by reason of which it can be intended, does not pertain to every agent or every intending subject. Not every agent considers more universal accounts: a particular agent considers only particular accounts, not common ones; therefore these are passed over by it, and it reaches them only because they are joined to the thing per accidens. But an agent that considers common and universal accounts can regard what is touched per accidens and omitted per se by a particular agent as contributing to its more universal end; thus it can fall within that agent’s intention, at least secondarily.

This doctrine brings together various passages of St. Thomas that speak about this matter and brings out the truth about how corruption is related per accidens and how it can be intended. Sometimes the holy Doctor affirms that corruption and other defects fall within the secondary intention of a universal agent, as in Summa theologiae I, q. 22, a. 2, ad 2: “Corruptions and defects in natural things are against particular nature, yet they are within the intention of universal nature, insofar as the defect of one thing contributes to the good of another or of the whole universe.” He teaches the same in Summa contra Gentiles III, c. 94, near the end, and c. 71; and he means nothing more, nor anything different, in the cited Sentences IV, dist. 36,¹² and De veritate, q. 23.¹³ For he speaks of nature absolutely, without distinguishing universal from particular nature. At other times he affirms that similar defects are wholly willed per accidens even by God, namely, by reason of the good to which they are joined. This is clear in Summa theologiae I, q. 19, a. 9, and q. 49, a. 2, where he says “that, by causing the good of the order of the universe in things, God consequently and as it were per accidens causes the corruptions of things.” Finally, in Summa contra Gentiles III, chapters 4, 5, and 6, he seems to mean that evil is always beside the intention.

These passages cohere as follows. Taken in themselves, these natural defects are certain privations and evils; under this consideration they are related per accidens both to a particular agent and to a universal one. For evil under the account of evil cannot be willed or intended, since it is not appetible but must be shunned by appetite. It can be related to an agent only per accidens, insofar as the agent either permits it—not by desiring it, but by not preventing it—or insofar as something else can be desired through it: that is, insofar as it takes on some account of good or some order to a good, whether common or particular. In this way it can fall under some intended act of willing or permitting. This intention, however, does not belong to a particular agent, because it belongs to that agent to intend only its own terminus toward which. Whatever belongs to the side of the terminus from which is not intended in any way, but is left aside—not even secondarily, since in order to be intended secondarily it would have to belong secondarily to the side of the terminus toward which. Corruption, however, belongs precisely to the side of the terminus from which with respect to a particular agent; therefore it can in no way fall within that agent’s intention, but is related to it only per accidens. A universal agent, by contrast, although insofar as it concurs with a particular agent in generation it also regards corruption as a terminus from which, can nevertheless, on account of its universality, reach what is a terminus from which under another account, as a terminus toward which—as something required for the common good, even with respect to its own corruption. God, for example, reaches every creature as a terminus toward which, and has nothing as a terminus from which. Hence he must provide for every creature, both as regards its existence and its corruption. Corruption is therefore not related to him per accidens as something omitted; rather, it can be intended at least secondarily, insofar as it takes on some order to good and is not considered purely as a privation. We shall speak in the third conclusion about other defects that follow from the necessity of matter. St. Thomas concludes in Summa theologiae I, q. 19, a. 9, that God wills the evil of a natural defect or the evil of punishment by willing some good to which that evil is joined. This is what it means for something to be within the secondary intention: it can be intended only on the presupposition of some good that it does not have in itself but derives from something to which it is joined.

YOU WILL SAY: Then there is no difference between the evil of guilt and the evil of punishment with respect to God’s will and providence, since the evil of guilt itself can be ordered to some greater good, such as this person’s humility or repentance. Yet St. Thomas distinguishes natural defects from the evils of guilt: God in no way wills the evil of guilt, because he does not will the good to which it is joined more than the divine goodness itself, which it opposes. But God can will the evil of punishment by willing some good to which it is joined.

We reply that there is a great difference between the evil of guilt and the evil of punishment. Although the latter signifies a privation and defect that can be ordered only by being joined to some good, the privation of the evil of guilt is opposed to order toward the divine good. It therefore cannot be joined to any good by reason of which it could be willed and ordered, since every good must be willed through subordination to the divine good. God wills all things only under the account of the divine good; accordingly, such evil can only be permitted by him—that is, not prevented by him—and the permission itself can be ordered to good. The evil of punishment or a natural defect, by contrast, is not opposed to the divine good, but to some particular good. It can therefore take on an order to some good that outweighs and is loved more than the particular good it destroys. By reason of this order, or of the good to which it is joined, there is no obstacle to its being intended and ordered by God, and not merely permitted.

I SAY, THIRD: Monsters and other natural defects that follow from the disposition of the matter from which something is generated are, with respect to a particular agent, sometimes fortuitous and in no way intended, and sometimes willed secondarily. With respect to a universal agent, however, they can be intended.

On this conclusion see the holy Doctor in Summa contra Gentiles III, c. 6, where he says: “If the privation is such that it deprives the generated thing of what is due to it, it will be fortuitous and simply evil, as when monstrous offspring are born. For this does not follow necessarily upon what is intended, but is repugnant to it, since the agent intends the perfection of what is generated. In natural agents, however, an evil of action occurs through a defect of active power. If an agent has a defective power, this evil follows beside its intention; it will not be fortuitous, because it follows necessarily from such an agent, since such an agent always or frequently suffers this defect of power. It will be fortuitous if this defect rarely accompanies such an agent.” So says St. Thomas.

Accordingly, a particular agent, because it intends only a particular good and acts according to a particular form, intends only to make its effect as perfect as it can; thus its intention concerns only the effect’s perfection and perfect likeness. That its power is defective or that the matter is improperly disposed is beside its primary intention, since arranging and ordering such indispositions or defects does not belong to its form; rather, it removes them as far as it can. But if it cannot remove them all and nevertheless acts, with a defect following, that defect sometimes follows wholly beside the intention of the particular agent and is therefore fortuitous, as are things that happen rarely: such things are fortuitous and wholly beside the intention. At other times defects follow not wholly beside the intention, but through a secondary intention, which is rather a non-rejection of the defect than a positive intention of it. This occurs when defects necessarily or perpetually accompany matter. For instance, an artisan who wants to make a sword chooses hard matter, such as iron, per se; but since rust follows iron and does not contribute to the artisan’s end but rather falls short of it, the artisan does not choose iron for rust as a primary intention. Because, however, the artisan finds no suitable material without this defect, the artisan chooses material with the defect through a secondary intention, on account of the hardness joined to it, which serves the end. In the same way, nature chooses matter suitable for the operation of the senses in the human body, and so it must be composed of contraries. But because diseases, old age, and other defects follow from that contrariety, they are beside the intention of the generator. Since suitable matter is not found without these defects, however, nature chooses it with them, at least through a secondary intention. These defects belong to the generated thing on the side of the matter and the dispositions that follow from it; they can therefore be considered on the side of the terminus toward which, as fitting to the thing generated by reason of the necessity of the matter from which it is formed. They can thus belong to the intention at least secondarily, since they follow necessarily from the matter chosen. The matter is chosen with these conditions, not because the conditions are chosen, but because they are not rejected; in this way they are reached in some fashion secondarily. For this reason a female is also sometimes said to be an accidental outcome: she is beside the intention of a particular agent, which intends the best effect it can, namely, a male. That a less perfect offspring, namely, a female, results is beside its intention because of an indisposition of matter or of active power, as St. Thomas teaches in Summa theologiae I, q. 92, a. 1, ad 1, Summa contra Gentiles III, c. 94, and De veritate, q. 5, a. 9, ad 9.¹⁴

With respect to the universal agent, namely God, none of these things is beside the intention, because God regards more universal ends and the order of the whole common good. Those things that seem imperfect, defective, or monstrous with respect to particular things also belong to the variety and structure of that order; for example, females are necessary for the multiplication of human beings. The manifold operation and power of nature is also manifest when there is an error in disposing matter and monsters arise. Many kinds of things are revealed through the monstrous mixture of seeds in fish, animals, and other creatures like them. God intends all these things not merely because of the necessity of the matter from which the defects follow, but for the sake of the common good, which is manifested and constituted even by things that have the account of good only through some presupposition, per accidens, or through another.

From these points one can answer whatever objections are commonly raised from the claim that sins, evils, and defects are not intended. The matter has already been resolved from what was said: we have shown how some things can fall under the intention at least secondarily, because they belong on the side of the thing generated, although a particular agent intends them only because of the necessity of matter, while a universal agent intends them because they contribute to the common good. We have also shown how some things are left aside per accidens and permitted, as corruption is with respect to a particular agent, since it belongs to the side of the terminus from which, and as aversion from the divine good is with respect to sin, since it can never be subordinated to the divine good under which the divine will reaches all things. Finally, it is clear how matter is inclined to corruption: by reason of generation, so that it can fulfill its potentiality for all forms. Thus matter—even singular and individual matter—considered according to its common potentiality for all forms and as subject to the universal agent who created it, can intend corruption secondarily, because corruption belongs secondarily to its good, for the sake of the succession of forms. The same matter, however, insofar as it is subject only to one form and to a particular agent that intends only that form, regards corruption only per accidens and on the side of the terminus from which.