Disputationes metaphysicae

1. The ancient philosophers (as Aristotle and the other authors cited in the preceding section report) who posited only one material principle of natural things almost all thought that it is some integral substance or simple body, such as Averroes thinks the heavenly body is. But concerning that body or material cause there was among them a manifold opinion.

Opinions of the philosophers about one material principle

2. The first asserted that this principle is water, whose author was Thales of Miletus; but others, as Plutarch, think it is more ancient and drew its origin from Orpheus. The second opinion attributes this function to air, which Anaximenes and Diogenes of Apollonia taught, as Aristotle reports, Physics I, c. 3, and Simplicius declares in the same place. The third opinion was that fire is a cause of this kind, which Hippasus and Heraclitus taught, and the Stoics followed the same, as is in Cicero, De natura deorum II. A fourth opinion could choose earth for this function, because it underlies all things and is as it were the common mother of all. Aristotle, however, Metaphysics I, c. 7, says that this was the opinion of the common people, but that none of the philosophers inclined to it, because earth on account of its excessive density and dryness seems unfit for receiving the forms or figures of other things. Hesiod, however, in his Theogony, absolutely calls earth the material principle of all things, and Theodoret reports that Pherecydes thought the same, in the book On matter and the world. The fifth opinion attributes this function to none of the four elements, but to a certain insensible body intermediate either between water and air, as Aristotle reports, Metaphysics I, c. 7, or between air and fire, as Anaximander, who added that this intermediate body is infinite, lest generation should ever fail; against which infinity Aristotle disputes elsewhere. But it seems to be gathered thence that this philosopher did not posit this body incorruptible; otherwise there would be no reason why he should fear that through the succession of generations it could be consumed if it were finite; although it can scarcely be understood how he made it corruptible, if he thought it to be a simple and common subject of generation.

3. Judgement is passed on the aforesaid opinions.—It would be prolix and superfluous to report the proper motives of all these philosophers, because they are both uncertain and show no probability or likelihood, as will be evident in passing from what is to be said. But this seems to have been common to all, that they thought nothing comes about simply anew, since from nothing nothing can come about; and therefore they seem to have recognized neither substantial forms nor substantial generation or corruption. Indeed many of them indicate that there are no accidental forms which are true beings, because they did not understand that any true thing can come about anew, but they thought that every change which we experience consists in various modes of being related of that thing which they thought to be the common matter. From which some went further, so that they said not that the material cause of all beings is one, but that all beings are one, not in number but in substance and essence; who, although they said a false and improbable thing, nevertheless spoke consistently, if they were treating only of general bodies. For, if these are not transmuted substantially, nor differ through substantial forms, but through accidents or diverse modes of being related, in truth there is no material cause of substance, but there is only a simple substance which is not essentially one and another, but one related otherwise and otherwise under diverse accidents.

4. And this was the opinion of Xenophanes, Parmenides and Melissus, who in this sense said that all things are one being, and that whatever is besides that is non-being; for they did not number the accidents or modes of that being among beings. And consequently they took away altogether every generation or change simply, because they made that being ingenerable and incorruptible; and accidental changes, because they do not give being simply, they did not judge worthy of the absolute appellation of changes. There are those who interpret the opinion of these philosophers in other ways, namely that by one being they understood one universe which embraces all things, as Aristotle indicates, De generatione I, c. 8, and Simplicius, Physics I, c. 2; or that by one being they understood God, who alone truly is. For Aristotle reports, Metaphysics I, c. 5, and Cicero, Academica II, that Xenophanes called that one being God. And so many and weighty authors think that these philosophers spoke through enigmas and hid the truth in figurative expressions; but that Aristotle attacked their opinions in so far as they seemed to be uttered in the very appearance and surface of the words. On which matter may be read St. Thomas, In Metaph. III, text 15; Philoponus and Simplicius, Physics I, c. 2; Eugubinus, De perenni philosophia III, from c. 5; Mirandola, Examen vanitatis VI, c. 1; and Bessarion, in the books Against the Calumniator of Plato. It matters little to us what these philosophers thought or what mysteries they hid in their words. There is no doubt, however, that, if they were ignorant of substantial forms, as they seem to have been ignorant, since they made no mention of them, they could easily and sufficiently consistently have fallen into that opinion as it has been explained by us. Whence by the proof and confirmation of substantial forms alone both this opinion and the others are refuted.

5. The opinion asserting a form of corporeity coeval with matter.—Another opinion, however, can be reported in this place, which many of the modern philosophers have followed, positing in prime matter a form of corporeity coeval with it and inseparable from it. For, although with respect to such form its material cause is simple, that is, without essential and physical composition, nevertheless that common subject which remains under every transmutation, and is the universal material cause of every generation and of every substantial form which comes about through eduction and of every composite which is generated—that subject (I say), according to the aforesaid opinion, is not simple but essentially composite, and some body, not mixed, nor yet any of the elements, nor intermediate between them through their participation, but absolutely body through prescission from all inferior forms. Which opinion Avicenna held, Sufficientia I, c. 2. Whose foundation is that the subject of generation must be corporeal and extended, and consequently quantified; but it cannot be such unless it has some substantial form. And Scotus and Henry followed this opinion in part; for the former, In IV, dist. 11, q. 3, a. 2, thinks that in all and only living things such a form of corporeity, or of mixture (as he speaks), is necessary; but the latter, Quodlibet I, qq. 2 and 3, and Quodlibet III, qq. 13 and 14, judges that it is to be admitted in man alone on account of the indivisibility of the rational soul. Whence these two authors do not posit this form inseparable from matter, nor as per se necessary for the first material causality of the subject of generation, but on account of other special causes; and therefore their opinion does not pertain to the present place.

Resolution of the question

6. The first conclusion.—It must be said, then, first, that the material cause universal and first in its order is not any of the sensible bodies or elements which are affected by contrary qualities. This assertion is against four opinions and is evident from what was said in the preceding section; for, if these elements and all sensible bodies are transmuted into one another substantially, none of them can be the first subject of transmutation; for the first subject, which is the first material cause which we are inquiring into, is not transmuted nor does it recede from its substance; otherwise it would be resolved into another prior subject, and so it itself would not be first. Moreover, since generation comes about between contraries, it is necessary that the common subject of generation have none of the contraries naturally innate in it; otherwise either it will never be capable of the other contrary, or it would be corrupted through the casting off of that which is connatural to it, as an element is destroyed when the quality necessary to it is taken away. Since, therefore, the individual elements are affected by proper qualities having a contrary, none of them can be an apt subject of generation; therefore neither can it be the first material cause of natural beings.

7. And hence arises a third reason, because there is no reason why this causality should be attributed to one element rather than to the others, nor yet why it should be more repugnant to all at once than to any one of them; but it has been shown that it cannot belong to all; therefore it is truly attributed to none. The former part of the major proposition is declared, because the individual elements are simple bodies, and each is apt and instituted for the generation of mixed bodies, and none of them can in any way consist of the others; for each has proper qualities repugnant to the others; therefore in all there is equal reason or repugnance against its being able to be the common matter of all generable things. For that in some there are certain conditions accommodated to the function of common matter—as is, for example, in fire subtlety, by reason of which it can easily penetrate all things; in air, that it is almost the common place of all things and easily receives external impressions; in water, humidity conjoined with that density which seems proportioned to constituting the nourishment of all things—these conditions (I say) matter nothing, both because they help rather either to the notion of effecting or to the notion of transient matter than to the proper and intrinsic notion of material cause, and also because those conditions, as they are accommodated to some things, so they are repugnant to others; for the subtlety of fire has proportion with the matter of subtle things, but not with the matter of dense things, and so of the others. But the first material cause, since it is common to all, must of itself be indifferent to all.

8. The other part of the major proposition is proved, because all the elements together cannot be the common matter, because they are transmuted into one another substantially; indeed neither can they compose a mixed body unless substantially transmuted; but this reason proves equally of each element taken by itself; therefore. Whence finally it is confirmed, because no element can be the matter of the other elements, as seems self-evident, since they are repugnant to one another. Nor, remaining in its nature, can it be the matter of any mixed body, since the form of the mixed body too fights with the form of the element; therefore no element can be the common matter of all natural things. And these reasons convince a fortiori of all mixed bodies, especially since those consist of elements; and therefore no one hitherto has attributed this causality to any mixed body.

9. The second conclusion.—I say, secondly: prime matter is not some body or substance complete and integral in the essence and species of substance. It can be understood in two ways that matter is a substance of this kind. First, so that it alone is the substance of all generable things and is only formed by their distinct accidents; and in this sense the assertion is to be proved from this, that natural things differ not only by accidents but also by substance and essence, as we argued in the preceding section against Epicurus and others. Likewise it is to be rejected (and it comes almost to the same) from the truth of substantial forms, which we are going to demonstrate in Disputation XV. For, that truth being supposed, it evidently follows that matter is not the whole substance of material things, and that these things differ not only by accidents but also by essence and substance, and are transmuted not according to accidents alone but also according to substance. Which is sufficiently evident also from experience itself; for, when a thing is changed in accidents alone, there remains in it some vestige of its properties and operations, or at least, contrary agents being removed, it is brought back to its state and nature; but we see some things so changed and destroyed that they altogether lose their prior properties and operations, nor ever return to them, even if every contrary action ceases; and conversely other things are so produced and generated that in that being which they acquire, as in their proper and connatural one, they remain constant, and according to it have proper and connatural operations and dispositions, which they preserve as far as they can; if sometimes they are weakened or diminished by some contrary, as soon as the contrary action ceases they recover them from their proper and intrinsic nature; it is therefore a sign that things are corrupted and generated not only in sensible accidents but also in their proper substance. And in these ways both the fifth opinion recited above and that which asserted that all things are one in the sense declared are attacked.

10. In another way, then, someone could feign that matter is a substance integral and complete in some species of substance, and nevertheless apt to receive further substantial forms and to compose with them the various substances and essences of material things. And this sense too is improbable: for either matter would be a complete substance altogether simple, or it would be composed of some substantial potency and act; this latter cannot be said, first, because then not that whole composite, but the potency of which it consists, would be the first material cause. It will perhaps be said that this is true with respect to that composite which is feigned ingenerable and incorruptible, but that with respect to all generable beings, or their generation, the first material cause is the whole composite. But against this it is objected, secondly, that such a composite is feigned without any foundation; for there is no indication or sensible sign of that form interposed between pure matter and the other forms which are induced through generation. Because that form has no sensible property by which it might be discerned; for the first qualities follow per se upon the form of the elements, and the temperaments composed of those qualities upon the forms of mixed bodies; but all the other qualities or properties which we experience suppose, at least in the genus of material and dispositive cause, the prior qualities; there is, therefore, no sensible or material indication of such a form. Whence it comes about, thirdly, that it is altogether superfluous, because there is no physical effect on account of which it is necessary: not for effecting, since it has no quality through which it could effect; from elsewhere, to each quality its proper form, to which it is connatural, suffices. Nor yet for receiving, for for this that potency suffices which is said to underlie such a form; for why could not that too be immediately subjected to the form which is induced through generation? And for the same cause such a form is not necessary for preserving that potency of which it is said to be the act, because for this too the form which is induced through generation is enough. Such a form, therefore, is feigned superfluously and without foundation.

11. Fourthly, there is added the impossibility of conjoining those two forms in the same potency or matter; for, although it is in question whether a form as it were generic and specific can at the same time actuate matter, which we shall touch upon a little below, nevertheless that two specific forms be conjoined at the same time to actuate the same substantial potency is plainly impossible naturally, and in this almost all authors agree. Because either those two forms would immediately actuate matter, or one would be the act of the other, or of matter as informed by it. The first cannot be said, especially according to that opinion, because otherwise the prior form would not necessarily be supposed to the posterior, nor would the composite of matter and such form be the proximate potency and material cause of the subsequent form. The second too cannot be said, because a substantial form constituting an integral and complete substance has the notion of last act in the notion of substantial and essential act, because it constitutes some last species of substance; therefore it cannot be compared after the manner of substantial potency to a further form. Finally, the general reason is that one and the same substance cannot be essentially and per se constituted in two lowest species; but through either form of those it is constituted in a proper and complete species of substance; therefore those two forms cannot be conjoined at the same time in the same matter. Otherwise any substance whatever, however complete, could be actuated by a further substantial form, because no greater reason can be given of one than of another. And to this also pertains that common reason, that a form coming to a being already constituted in act does not make one per se, but per accidens, from Aristotle, Metaphysics VII, text 49, and De Anima II, text 7; and therefore it cannot be a substantial form, but accidental, because a substantial form constitutes one per se, not per accidens. And the reason is that a substantial form gives being simply and essential being, and therefore cannot suppose a thing constituted in being simply and in complete and consummated essence. But an accidental form gives being in a certain respect, which is adjoined per accidens to a consummated essence. It is impossible, therefore, that the subject which is the material cause of generable things and of substantial generation be a complete substance constituted by a proper and specific form.

12. And these reasons prove equally efficaciously that that subject cannot be a simple substance integral and complete in the notion and species of substance, because it would be impossible that such a substance be further actuated and completed by a substantial form. For, if this is repugnant to a composite substance, much more to a simple one, which through itself is in complete and perfect act. For that repugnance does not come from composition, but from complete actuality in the notion and essence of substance, which cannot within that genus be further actuated substantially and essentially; but this reason of repugnance has place by the same or greater reason in a simple substance, if it is supposed integral and complete in the genus of substance. And by this reason an immaterial substance cannot have the notion of substantial potency to a further form, because it is a complete simple substance; and the same holds of the substance of the heaven, if it is physically simple, as many hold; for it is complete in some species of substance, and therefore cannot be further substantially actuated; prime matter, therefore, which can be actuated substantially and compose with substantial form a being per se one, cannot be such a simple substance, which is integral and complete in the genus of substance.

13. The third conclusion.—I say, thirdly: the material cause of generable things is not a substance composed of substantial potency and some incomplete and as it were generic substantial form. Almost all authors commonly approve this assertion against Avicenna, especially those who deny that there are several substantial forms in the same composite, as St. Thomas, I, q. 76, aa. 3 and 4, Contra Gentiles II, c. 58, and In Metaph. VII, lect. 12, whom the Thomists follow: Capreolus, In II, dist. 15, q. 1; Cajetan, in the said place of the First Part, and De Anima II, c. 1; Ferrariensis, in the cited place of the Contra Gentiles; Soncinas, Metaphysics VIII, q. 8; Javellus, q. 4; Soto, Physics I, q. 7; Astudillo, De generatione I, q. 1; and in the same place Marsilius, q. 6; and Albert of Saxony, q. 5; and at length Giles, treatise De pluralitate formarum, and De Anima II, dub. 6. The same was taught by Philoponus, De generatione I, at the beginning; Themistius, Physics V, text 7; and the Commentator, book De substantia orbis, and Metaphysics I, text 17, and Physics I, texts 65 and 69. Indeed Avicenna too, De Anima I, part I, c. 3, signifies that in corruption matter alone remains; and Sufficientia I, c. 3, he doubts whether in corruption corporeity perishes, as he speaks. Aristotle too, De generatione I, text 12, and in other places cited above, openly indicates the same opinion. Various reasons are brought forward by the Doctors; but two seem to suffice, which can be taken with proportion from the proofs of the preceding assertion.

14. The first reason is that in nature there is no indication of such a form perpetually coeval with and inseparable from matter, nor any effect on account of which it is necessary; therefore such a form is feigned without foundation or necessity. The antecedent is proved, because that form has no quality proper to itself through which it may be known, nor can it be gathered from substantial transmutation; because from transmutation of this kind it is only gathered that there is some substantial subject of it. But that it is composite is neither necessary for the notion of subject, nor can it be inferred from any other indication. You will say that for the notion of a subject of physical change it is required that it be extended and divided from others; and for this it is necessary that it have some form, because matter alone through itself is not capable of extension and division, for it is act which distinguishes; for this was the foundation of the contrary opinion. But this reason is of no moment, because, whether we think that quantity and extension precede simply in the order of nature in prime matter for substantial generation, or think that it follows upon the form introduced through generation and affects the whole composite, in neither way is it necessary that the subject of generation be composed of matter and some form. Each part is declared; for, if quantity is supposed to the form to be induced through generation, it can easily be understood as inhering in the very entity of matter; for, as we shall show below, it has a true and substantial entity.

15. And it is confirmed, for that composite which is feigned of matter and the form of corporeity is something incomplete and so potential that it naturally desires a further form, without which it cannot be either at all or at least in a connatural way. And nevertheless that composite is said to be a sufficient subject of quantity prior in nature to receiving the further form; much better and more easily, therefore, will that whole capacity be attributed to the simple entity of matter, because no greater repugnance as regards this can be feigned in a simple entity than in that composite; nor will the actuality of such an entity, whatever it is, be more repugnant to union and per se composition with the last substantial form than the actuality of that composite of matter and form of corporeity; therefore, according to this mode of opining, that form is not necessary. But it is less necessary if we think that quantity follows upon the form which is introduced through generation; for according to this opinion quantity supposes in the order of nature a substance composed of matter and proper form. Whence it will consequently have to be said, according to that opinion, that before the instant intrinsic to generation, in the whole time in which the previous alteration comes about, matter is supposed extended in itself and divided from others through quantity and the form of the thing to be corrupted; but in the instant of generation it is preserved extended and divided through the form introduced and the quantity accompanying it in the same instant; there is, therefore, no natural effect, nor any sign, by reason of which such a form or composition on the side of matter is to be admitted.

16. The second reason is that a form of this kind is incompossible in matter with the subsequent forms. But this is commonly wont to be proved from that maxim, that from two beings in act one per se does not come about; for the first substantial form constitutes being in act absolutely and simply, because it gives being simply; therefore no supervening form can constitute a being per se one and simply. But to this reason it can be answered that it only proceeds of a substantial form giving specific and ultimate being; for that which gives precisely generic being, although it has the notion of act with respect to matter, is nevertheless compared as potency to the inferior form, and because it is of the same genus it will be able to constitute one per se with its act. For so these authors philosophize about physical forms, as we all reason about metaphysical differences, in which the subaltern difference is an act actuating the superior genus and constituting its proper species, which nevertheless is a potency to the inferior difference, with which it metaphysically composes a being per se one. So, then, it must be said, according to the aforesaid opinion, of physical forms. Whence, when it is said that every substantial form constitutes being in act simply, it will be answered that this is true, proportion being kept; for the generic form constitutes being in act in the generic grade, but the specific form in the specific grade. And with similar proportion that maxim will be distinguished: What comes to a being in act comes accidentally.

17. No form can give a precisely generic grade.—Wherefore, in order that that opinion may be radically attacked, it must be proved by us that there can be no form which gives precisely generic being without also giving some specific being in that genus; for, this being proved, the discourse made proceeds excellently, because every substantial form constitutes being in act simply and in some lowest species of substance, and therefore it is impossible that the composite constituted through such a form be further actuable through a substantial form. But that assumption is proved, first, by induction, both in accidental forms and also in separated forms. For qualities too are conceived to give specific being, as to be white, and generic, as to be coloured, etc.; and yet there is no accidental form which in the thing gives precisely generic and not some specific being. Similarly in the angels there is the generic notion of spirit and the proper specific difference; but there cannot be, indeed not even be conceived, some separated form which is a spiritual substance and which in the thing itself stops at this precise and generic notion; by the same reason, therefore, in substantial forms which are as it were intermediate there cannot be a form which in the thing precisely gives the generic grade; for no reason of diversity can be assigned. Whence I argue, secondly, from the proper notion of form itself, because a form existing in the thing itself cannot be understood which is not essentially constituted in some lowest species of substantial form; but every form communicates to the composite its whole being and its whole essence; therefore it constitutes it in some lowest species of composite substance. The consequence with the minor are evident, and can excellently be declared by the induction made in the first reason. But the major too seems most certain, because every substantial form has a proper entity distinct in the thing itself from matter or other forms; therefore it is necessary to understand in that entity an ultimate and proper difference or notion through which it is essentially distinguished from other forms having a diverse essence, with which it agrees in the common notion of substantial form; therefore every substantial form is necessarily constituted according to its entity in some lowest species of substantial form.

18. The prime matter of generable things claims for itself a stable and atomic species.—You will say: prime matter too has its proper substantial entity, and yet according to itself it is not constituted in some lowest species, but is only reduced to the genus of material substance, until it is determined by the form to some particular notion; therefore the same could be said of the common form coeval with matter. I answer that the assumption is false; for the prime matter of generable things, of which we are now treating, is essentially constituted in some lowest species of matter, which it retains under every form, nor can it vary it, but at most by superadded accidents it can be accommodated to this or that form. But because that essence of matter, although in itself specific and lowest, is such that in the thing itself it can be communicated to several substances essentially diverse, therefore, regarded according to itself, it is said to be reduced to material substance of generable things as such, and not to some species of it. Whence in passing it is gathered that the concept of generable substance as such is not generic by reason of matter, but by reason of the common grade or agreement in form.

19. You will press: matter, even if in its essence it has the ultimate specification of matter, is nevertheless common to many substances essentially diverse; by equal reason, therefore, although the form of corporeity in its entity and essential concept has some ultimate specification, it will nevertheless be able to be common to many substances having further diverse essential notions.¹ I answer that the reason is unlike; for the essence of matter is to be as it were the foundation of an integral and composite substantial nature, and therefore it is only a certain inchoate essence (so to speak) after the manner of potency, and on that account is of itself indifferent to being completed by various acts; but form is the complement of the substantial nature and essence, and therefore, by the very fact that it has a determinate and specific notion of form, adjoined to matter it completes with it an integral substantial nature constituted in some lowest substantial species, and therefore does not leave that nature indifferent to a further species. Wherefore all who posit a form of corporeity in all or in some natural beings consequently say that that form is constituted precisely in the subaltern grade of corporeity without any essential contraction, which in truth is unintelligible.

20. And consequently they will also admit that the composite of matter and such form, if in the thing itself it is preserved without a further form, is an individual of the genus of corruptible body and is constituted in no lowest species of it. But that it can be so preserved by absolute power seems evident, speaking consistently, since the inferior forms are really distinguished from that composite, and it will be evident a fortiori from what we shall say below of matter. But Scotus thinks that this is possible even naturally, as, for example, in the death of a man or another similar case; for he admits there substantial corruption without generation, and that the corpse is nothing other than this individual body affected by these accidents and constituted in no inferior substantial species. But this consequent seems to me of itself absurd and incredible; for this individual body existing per se without any specification can no more be conceived than this spirit outside every species, or this coloured thing affected in the thing itself by this colour and by no species of colour. And the reason is that touched upon above, because an individual entity necessarily differs essentially from others, and therefore it is necessary that it be constituted in itself in a proper essence not common to others. Whence it is confirmed, for from the said position it follows that the generic and specific notion are really distinguished in one and the same thing, because they are taken from really distinct forms; but the consequent is evident to be false from what was said above of universals, and it will also be declared in the following reasons.

21. Absurdities from the opinion asserting a form of corporeity.—Worthy of note.—The third reason is taken from the difference between essential physical and metaphysical composition, which to wish to equate in this is the cause of error, since the one exists in things, the other in concepts. I argue, then, for if there can be given a physical form which confers only the generic grade, then as many as are the generic and specific grades of material substances, so many substantial forms really distinct will have to be multiplied; the consequent is false; therefore. The sequel is proved from parity of reason; for what reason can be brought forward on account of which some generic grade is given through a proper form really distinct and not others? Especially because, according to the opinion which we are attacking, not only in things which seem to be elevated to a higher grade of bodies, as are living things, but also in the lowest and inanimate bodies, the form giving the being of body is distinguished from the form giving the being of fire or of stone or something similar; which contraction is with the least diversity which can be between some genus and a substantial difference; if, therefore, that suffices for a real distinction of forms, any whatever suffices; whence there have not been lacking philosophers who admitted that consequent; yet it is not only false but also ridiculous. First, because it is evidently established by the induction made above that for abstracting the concepts of genus, difference and species that real distinction of forms is not necessary, as is evident in the angels and in accidents. Secondly, because it follows that three souls are to be multiplied in man, which is an altogether false opinion, as I suppose from the science of the soul. Indeed even more will have to be multiplied; for in the grade of sensing some essential agreement can be abstracted between man and some perfect animals which is not common to all animals, and in the notion of understanding a generic notion common to man and the angels can be abstracted, which is contracted to man through a proper difference. Whence it further follows that innumerable forms really distinct are to be asserted in individual composites, because generic and specific differences can be multiplied in various ways according to the various agreements and differences which can easily be considered in things, and according to them various common or particular concepts can be abstracted. It is, therefore, a great error in metaphysics and philosophy, on account of our confused or distinct mode of conceiving, from which the multiplication of genera and differences often arises, to distinguish real and physical forms. Otherwise not one only, but two or three forms of corporeity would have to be posited: one of body in common, as it is genus to corruptible and incorruptible, simple or mixed; another of corruptible or mixed body as such. All which are ridiculous. Whence not only is it not necessary on account of these operations of the mind to multiply the forms themselves, but it is even repugnant to them, because it is of the notion of proper genus and proper difference that they express the same essence of the thing diversely conceived.

22. Which finally is confirmed, because it is impossible that there be given a substantial form giving the specific grade of substance which does not give also that generic grade and the formal effect which the distinct form of corporeity is feigned to give; therefore such a form is both superfluous and impossible. The consequence is evident, because the same essential predicate and the same formal effect cannot belong to the same thing through two forms really distinct. But the antecedent is proved, because there cannot be given a substantial form conferring the specific grade which does not essentially include the common and generic notion of substantial form informing matter; but this precise notion suffices for constituting the form of corporeity; therefore the form of corporeity is not a special form, but is any substantial form whatever considered according to the common notion of informing substantial form. The minor is proved (for the rest are clear), for from the precise fact that some substance is understood as composed of matter and substantial form, it is essentially a corporeal substance, or a body of the predicament of substance; for by virtue of such composition it is both essentially distinct from incorporeal substance and capable of quantity or threefold dimension, in which the notion of corporeal substance consists. Whence the form of corporeity as such neither expresses nor requires that it itself be corporeal or extended, but only that it inform matter, by reason of which the composite resulting thence is capable of threefold dimension; there is, therefore, no necessary or possible intermediate form which gives the generic being of body, but any substantial form whatever by virtue of its generic notion confers it.

23. The conclusion is inferred from all that has been said.—It remains, therefore, from all that has been said, that the first material cause of generable substances is not some integral substance, nor any body or composite of matter and form; and accordingly that for the generation of substances there is not supposed, after the manner of a subject in which generation is received, some ingenerable and incorruptible body, but prime matter alone—alone (I say) as regards substance; for as regards accidents what is to be said we shall see afterwards.