Cursus Philosophicus Thomisticus, Secunda Pars Philosophiae Naturalis

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.