Cursus Philosophicus Thomisticus, Secunda Pars Philosophiae Naturalis

To know and distinguish substantial generation among the many actions that concur in it, we must investigate two things. First, whether substantial generation is an action and change distinct from the whole dispositive action that works upon matter through alteration, or whether, once alteration has been brought to the final disposition, generation results without a new action. Second, within the generative action itself, what formal aspect we should assign as constituting the very notion of substantial generation. For the generative action includes the notion of eduction or production of a form, likewise the union of form with matter, and also conversion and similar notions; among these we must discern what formally belongs to the notion of generation. As for the actions following generation, there is no need to investigate how generation is distinguished from them: once generation is completed and has passed, it is clear how the remaining actions are distinguished from it and do not constitute generation but presuppose it, as nutrition, growth, and the like. From what principle substantial generation immediately proceeds at the instant when it is completed and the form is introduced, we shall say in art. 7.

First difficulty.

On the first question, some hold that generation is not an action distinct from alteration. Rather, once alteration is posited, generation follows it as something that results; this is called generation and stands as the terminus of alteration—not something produced by alteration and specifying it, for that is a quality, but something consequent and resultant without a new exercise of efficient causality, because of its natural connection with those dispositions, just as proper attributes result from an essence once it is posited, without a new exercise of efficient causality.

Their first basis is drawn from certain authorities of St. Thomas, in which he often repeats that generation is the terminus of alteration. In particular, in the treatise On the Nature of Matter, that is, Opusc. 42,¹ he says: “Alteration, by which matter is stripped of its prior form, requires in itself a subject actually existing, because it is a motion; but at its true terminus it does not require a subject actually existing, and its terminus is generation.” Speaking of the generation of a human being, ST I, q. 118, a. 2, ad 4, he says that “a human being generates its like insofar as, through the power of its seed, matter is disposed to receive such a form.” Here St. Thomas locates generation even precisely as the generation of a like thing in the seed’s dispositive action.

Next, they draw support from reason: accidents by themselves cannot produce a substance through a substantial action distinct from an accidental one, since an accident does not produce per se; nor can a substance immediately produce such a distinct action per se, since it is not immediately operative. Nor can an accident, as moved by a substance, produce that distinct action, because the same difficulty arises concerning that motion: how does it proceed from the substance without another accident as intermediary? If the accident does not receive a new and more excellent motion in order to produce a substance, then the very same action by which it produces the accident, without becoming more excellent or elevated, produces the substance. This is the intended claim: the same action that reaches heat passes on to the substance of fire, with the heat posited as resulting from its connection with that substance.

Nevertheless, the opposite must be maintained: generation is an action distinct from alteration, and substance does not result from alteration or from the quality produced by it, as proper attributes result from an essence. Rather, substance is produced by a true exercise of efficient causality distinct from the efficient causality by which the quality itself is produced through alteration.

Nor did St. Thomas ever say that substance itself results from alteration or from the quality produced by it. He said that generation—that is, the action itself—is the terminus of alteration. If substance resulted from alteration, he would not say that generation is the terminus of alteration, but that the thing itself generated is its terminus. If generation itself is the terminus of alteration, then it is an action distinct from alteration.

That St. Thomas posits generation itself as an action distinct from alteration is clear first because, in SCG III, ch. 69, he says: “If accidental forms, which are in corporeal things, have their own actions, much more does a substantial form have some action proper to it. But the action of such a form is not to dispose matter, since this is done through alteration, for which accidental forms suffice. Therefore the form of the generator is the principle of an action by which a substantial form is introduced into the thing generated.” Thus St. Thomas distinguishes the action introducing the substantial form from the action disposing matter, which is alteration; he says an accidental form suffices for the latter, whereas the former requires the substantial form of the generator, though not as its proximate principle.

Again, generation and corruption are called termini of alteration in such a way that they also have further termini; insofar as they have further termini, they are not the generated or corrupted substance itself, but an action or tendency toward it. The antecedent is proved from St. Thomas, ST II-II, q. 164, a. 1, ad 7, where he says: “Death can be taken in one way for the privation of life itself, and in another way insofar as it names the corruption itself, which terminates in the aforesaid privation. We can speak of corruption, as of generation, in two ways: in one way, as it is the terminus of alteration; in another way, corruption can be taken together with the preceding alteration, insofar as someone is said to be dying while being moved toward death.” Behold how St. Thomas both acknowledges that corruption, like generation, is the terminus of alteration and says that corruption terminates in privation. Generation, then, likewise terminates in the opposite of privation, namely, form. He therefore holds that generation and corruption are not only something distinct from alteration as a produced or resultant terminus, but are actions, since they are directed toward a terminus.

The basis for the assertion is this: the alteration that proceeds throughout the time preceding the instant of generation exists in a subject that is ceasing to be and being corrupted. Therefore the generated substance itself cannot result from that alteration unless a new and distinct action intervenes to produce the substance.

The antecedent will be established below, arts. 6 and 7, and is conceded by the proponents of the opposite view, since alteration, being a motion, is not received in bare matter but in a composite. Before the instant of generation, however, the generated composite does not exist; rather, the composite to be corrupted exists at the instant of generation. Therefore alteration is received in that composite.

The consequence is proved as follows. Generation cannot result from alteration in the subject in which the alteration exists, since that subject is corrupted by generation; thus generation does not result in it, for the thing generated and the subject in which the alteration preceding the instant of generation exists are incompatible. If generation instead results in another subject, in which the alteration does not exist because that subject is corrupted along with the former subject, then generation cannot result from that very alteration; otherwise it would result from what destroys it. This is impossible, since resultant properties are grounded in a necessary and per se connection of one thing with another, whereas there can be no necessary connection, by way of such resultance, with what is incompatible with it.

It cannot be said, then, that this resultance requires alteration to exist at the very instant when generation results, but that it suffices for alteration to have existed immediately beforehand and to remain virtually at the instant of generation. For the whole force of our argument rests on this: something cannot come to be by resultance, rather than by a new action, precisely when it does not exist but is incompatible with that thing. Resultance, as distinguished from action, is grounded in the necessary and per se connection of one thing with another, such that when the one exists, the other exists as resulting from it, since they come to be through the same action; when the first ceases, the second also ceases, as a proper attribute results from an essence and exists with it.

But alteration, as an action and motion, ceases in the very subject that is corrupted and does not exist at the instant of generation. Therefore the generated thing does not result from it, nor does it have being from it by resultance, since it is rather incompatible with it at that same instant.

If you say that the connection exists because that disposition necessitates generation, the reply is that a connection and necessity do exist between one action and another—namely, between the alterative and generative actions. Thus, given the first action, the agent is necessitated to perform the second, just as, once assent to the premises is given, the intellect is necessitated to assent to the conclusion. Yet assent to the conclusion is an act distinct from assent to the premises. This connection between actions presupposes that generation is a distinct action; otherwise it would not follow, by force of the connection, as distinct from the first action. It does not mean that, through the force of a mere connection, another thing results from the very same action that produces one terminus, without a new action, as proper attributes result.

To the first basis for the opposing view, drawn from the authorities of St. Thomas, we reply that when he says generation is the terminus of alteration, the meaning is that it is alteration’s end as a more principal action toward which alteration is ordered—not an object produced by resultance, but a distinct action that necessarily arises from the generator once alteration has been presupposed as disposing. It is like saying that assent to the conclusion is the terminus of assent to the premises. This is clear from St. Thomas’s own teaching. In Quodlibet II, a. 4,² he says: “Through alteration matter is disposed to form, and through local motion a luminous body approaches a position from which it illuminates; accordingly, generation and corruption are called the terminus of alteration, and illumination the terminus of local motion.” He says similar things in ST I, q. 53, a. 3, where he compares local motion in relation to illumination with the motion of generation in relation to alteration. But it is clear that illumination is an action distinct from local motion; therefore substantial generation too is an action distinct from alteration. This also explains what St. Thomas says in Quodlibet VII, a. 9,³ that alteration has two termini, namely, a quality and a substantial form. It is understood to have two termini not by one terminus resulting from the other, but by this action being ordered to another. The same interpretation applies to his statement in Opusc. 42,⁴ that generation is the terminus of alteration: it is the terminus as an end, as a distinct and more principal action, not because the generated substance itself arises from alteration by resultance without a new action.

As for what is adduced from St. Thomas concerning the generation of a human being, we reply that a human being is said to generate its like insofar as matter is disposed through its power—not by producing or drawing the form out of matter, as in other generations, but because, by disposing matter, it unites the form to it and thus reaches the form as united. This interpretation is taken from St. Thomas himself, De potentia, q. 3, a. 9, ad 6,⁵ where he says that in other generations “the generator is the cause of the form itself, but in the case of the rational soul it is the cause of the union of such a form with matter by disposing matter for it; it need not be the cause of the form itself.” St. Thomas does not say whether, just as in other generations the form is produced by a distinct action apart from the disposing alteration, so in the case of a human form reached by union it is reached through a distinct action.

There are different opinions on this point. Ferrariensis, in SCG II, ch. 89,⁶ seems to admit only that through the power of its seed a human being produces the dispositions by which the body is disposed to share in the rational soul; the soul’s union with the body necessarily follows those dispositions, and on this account the power of the seed is the cause of that union. This is because a human action cannot terminate intrinsically in the rational soul, which is spiritual; it therefore terminates only in what belongs to the side of matter, namely, the dispositions.

Cajetan, however, ST I, q. 118, a. 2,⁷ allows more than a merely dispositive reaching: he allows an action that terminates per se in the union of the soul with the body. This union does not belong to the side of the soul, for in that respect the soul is infused by God when it is created in the body; rather, it belongs to the side of matter, insofar as the action not only produces dispositions but also makes matter subject to the form. It does not reach the form’s very act of being, but its being-in or communication to matter, insofar as matter, in a corporeal and material way, is subject to and united with the form. The action terminates in the soul insofar as the soul eminently is a corporeal form, although it is spiritual in itself. In this way, the proper and formal sense in which a human being generates a human being is preserved, as is the claim that the human form is the formal terminus of generation insofar as it informs and is communicated to matter.

To the argument from reason, we reply that generation, as an action distinct from alteration, proceeds from a substance through accidents insofar as they have the character of instruments of the substance, as we said in Physics q. 12⁸ and as is drawn from St. Thomas, SCG III, ch. 69, and ST I, q. 115, a. 1, ad 5, where he says: “A body acts both toward an accidental form and toward a substantial form. For an active quality, such as heat, although an accident, nevertheless acts by the power of a substantial form, as its instrument. Therefore it can act toward a substantial form, just as natural heat, insofar as it is an instrument of the soul, acts toward the generation of flesh; but toward an accident it acts by its own power. Nor is it contrary to the nature of an accident to exceed its subject in acting; what is contrary to it is to exceed its subject in being.” Thus St. Thomas. He acknowledges that an accident has sufficient motion to reach a substance precisely by being the power of a substance, rooted in that substance, and producing as something belonging to it and as its instrument. Otherwise it would produce only by its own power, if it operated precisely insofar as it is a quality and not as something belonging to a substance. What this motion adds to the power itself, making it an instrument of a substance, we explained in the cited q. 12, a. 3; see also St. Thomas, ST I, q. 118, a. 1, ad 2, where he says: “That active power which is in the seed, derived from the soul of the generator, is, as it were, a certain motion of the generator’s soul itself; it is not the soul or a part of the soul except in power, just as in a saw or axe there is not the form of a bed, but a certain motion toward that form. Therefore this active power need not have an organ actually; rather, it is founded in the spirit enclosed in the seed.” He teaches the same in De anima, a. 11, ad 2.⁹ St. Thomas thus acknowledges that this power has no other force than the motion of the generator, which is nothing other than the issuing forth of that power from the generator itself; once the power has issued forth from the generator, it receives no further motion in it.

If you object that in instruments the same action that reaches its proper terminus, when elevated, reaches the principal agent’s terminus, then similarly the generator’s instrumental power reaches by the same action of alteration its proper terminus, a quality, and by that same action as elevated reaches the substantial form as generation. We reply that this no longer concerns the view we are opposing, which says that the generated thing itself results once alteration is posited. The objection instead concerns true efficient causality that reaches the generated thing instrumentally through alteration. The truth, however, is that alteration is not the very instrumental action which, through elevation by a higher agent, reaches the principal effect. It is a prior action with its own terminus, a disposition; it is received in the thing to be corrupted and is ordered to the generative action as a principal action, which follows and inheres in the thing generated. The generator’s power therefore acts in a certain order through two ordered actions: first, through alteration, toward a disposition, which is its proper terminus; second, through substantial generation, in which it acts through a certain motion of the generating substance. In this latter action the power has the character of an instrument. Although it first acts as a principal cause to produce its proper effect, the disposition, it later reaches the generated substance instrumentally as a power of the generating substance. Nor must the action that first produces a disposition always be the same action as the one that introduces the principal form in instruments; the actions can be distinct, especially when the prior disposition must be corrupted through the production of the principal form.

Second difficulty.

Concerning the second difficulty, note that generation has several formal aspects or respects. It has the character of change, conversion, eduction or union, production, and finally corruption, which follows from it.

It has the character of change in relation to its subject, matter, precisely insofar as it reduces matter’s potentiality to act. It has the character of conversion also in relation to matter, with reference to the forms: matter leaves one form and receives another, and thus turns one into the other. It has the character of eduction in relation to the form, insofar as the form comes to be and exists dependently on matter and through its transformation. It has the character of union insofar as it brings both matter and form into relation and changes them toward the sharing of the same unity in the composite. It has the character of production in relation to the whole composite, which it newly brings into being, or also in relation to the form which it draws out. Finally, it has the character of corruption in relation to the prior composite, which it destroys. It need not destroy the form, as is clear in the corruption of a human being; it suffices that it remove the form from matter and corrupt the composite.

All these formal aspects belong to one and the same action. This is clear because that action proceeds from one power and tends toward one singular terminus. Every action existing as an individual, however, regards a terminus from which, a terminus toward which, and a subject; therefore it grounds all these formal aspects or respects, which are found in matter, in form, in the termini from which and toward which, and in their relation to one another.

In which of these formal aspects generation consists more essentially and properly, we shall say in the following article, treating the formal terminus of generation; for this resolution depends on determining what the formal terminus of generation is. Since generation is an action and change, it is clear that it should be taken more formally by its order to the terminus toward which than by its formal aspect and respect to the terminus from which.

It only remains to note how generation is called conversion; this will become clear by explaining what conversion requires.

Five things are required for conversion. First, the converted terminus, which is the terminus from which, must cease to be, for if it remains, it is not turned into another. Second, the terminus toward which, or converting terminus, must begin anew, either absolutely in its being or at least in some new mode of being, just as Christ is in the Eucharist in a different way from how he is in heaven. Third, there must be some connection or dependence between the converted and converting termini, insofar as one succeeds the other; thus at least in their succession they are connected. Fourth, conversion must be between positive termini, one of which is corrupted and the other generated; the former must not be corrupted absolutely, as though by annihilation, but must cease by passing into that into which it is converted. Fifth, something common to both termini, the converted and the converting, must remain, either as a subject, as in generation, or as an extrinsic accident, as in transubstantiation. It may seem probable that God could absolutely effect a conversion without this condition—for example, if he converted the whole substance of the bread and its accidents into the substance and accidents of Christ or an angel—but then it would not have the character of conversion so properly.

Hence it is clear that conversion has a different formal aspect from motion, although both concern positive termini in order to establish a range and a distance to be overcome by motion. Conversion, however, does not regard positive termini insofar as they establish a range and distance to be traversed by motion, since conversion can be preserved without motion, as in transubstantiation. Rather, it regards them insofar as something does not come to be from nothing, but something is presupposed to be transferred and changed into another.

Conversion is either substantial or accidental. Accidental conversion occurs when a transition is made from one accident to another, as when something white becomes black; this is always joined with motion. Substantial conversion occurs when a transition is made from one substantial form to another; it always has joined to it two changes, one generative and the other corruptive.

Again, conversion is either formal or total. Formal conversion occurs when, while some subject remains, a transition is made from one form to another. Total conversion occurs when an entire entity or substance passes into another with no common subject remaining, as in transubstantiation in the Eucharist. This cannot occur naturally, because no natural action operates except by presupposing a subject or matter, and does not destroy it. On this see St. Thomas, ST III, q. 75, a. 8, where he identifies the modes of speaking about these conversions.

From these points we conclude that generation is conversion. Although generation has privation as its formal terminus from which, this antecedent privation is naturally joined to some positive form; for this reason, the generation of one thing is always the corruption of another. The form that is corrupted is not annihilated but ceases by passing into another. Therefore a conversion truly and properly occurs in substantial generation. The formal aspect of conversion differs from that of generation because generation has privation as its terminus from which, while conversion has a form as something to be changed into another that succeeds it. Thus there is one action but two changes, as was said,¹⁰ because two forms are changed: one passes from nonbeing to being and comes to be anew; the other is corrupted, passing from being to nonbeing. The action, however, is one, because one causality flows from one agent and regards two termini, one from which and the other toward which; between them there is established one distance to be traversed by motion and action. In the generation and corruption of a human being, however, there is no conversion into the substance of the rational form or from it, since it does not cease to be; rather, the conversion is into the form insofar as it informs, or from it insofar as it ceases to inform.