Disputationes metaphysicae

1. That genus and difference are distinguished in the thing can seem to be persuaded by these arguments: first, because the species is composed of genus and difference, which composition is called metaphysical and is not thought to be altogether feigned through reason, but in some way found in things themselves; and therefore the more approved theologians teach that it is not found in God, because it is repugnant to his supreme simplicity; it is therefore a sign that genus and difference are in some way distinguished in the thing itself, and not only by reason or our concepts, because otherwise they would not make a composition in the thing; for a distinction of reason alone, even founded in a virtual distinction or eminence of the thing, does not suffice for a true composition of the thing; there is therefore in the thing some distinction between genus and difference. And it is confirmed, for by this reason Aristotle, Metaphysics VII, c. 10, text 33, having said that the definition must consist of parts, namely genus and difference, subjoins: as the definition is related to the whole thing, so the parts of the definition to the parts of the thing; there is therefore between them some true distinction, as between the parts of the thing.

2. Secondly the same is proved, because things which in the thing itself have integral or partial essences in some way diverse are in some way distinguished in the thing itself; but genus and difference are so related; therefore. The minor is proved from the things which are commonly attributed to genus and difference. For first of all Aristotle, Metaphysics III, text 10, says that the difference is outside the notion of the genus; the difference, therefore, is not of the essence of the genus, nor conversely. Whence, Topics VI, c. 3, Aristotle says that neither does the genus participate the differences nor the differences the genus; and Metaphysics VII, c. 12, text 42, he says that the differences are not placed in the notion of the genus, but that the genus is compared to the differences as potency to essential act, and that therefore one per se comes about from them. And it is evident by reason, for the differences dividing the genus are opposed among themselves; therefore both cannot be of the essence of the genus; therefore neither the one nor the other can be of its essence. The consequence is evident, both because there is no greater reason for one than for the other, and also because, if one were of the essence, it would be inseparable, whence the other could never belong to it, since opposites cannot be at the same time in the same thing; the genus, therefore, has an essence of itself distinct from the differences, or not including them. But that conversely the difference too expresses an essence not including the genus is evident, both because otherwise the genus would be transcendent, and also because otherwise the difference would include all that the species includes, whence a certain nugation would be committed when the difference is adjoined to the genus.

3. A third argument can be that things which are separated in the thing must necessarily be in some way distinguished also in the thing; but the inferior and superior grade are separated in the thing, for somewhere there is the notion of animal where rational is not found, and so of the others. A similar argument is that in the thing itself two species are similar in the generic notion, but not in the specific; whence it seems necessary that these notions be distinct in the thing itself. Likewise, that the difference contracts the genus and actuates it; therefore they are not altogether the same, because the same thing does not contract itself. Fourthly I argue: because these expressions, precisely and abstractly, are false: Animality is rationality and similar ones; and only on account of a formal distinction; for, if subject and predicate were altogether the same, the affirmative proposition would be true; but by those words the generic and differential grades are precisely signified; these grades, therefore, are distinguished from the nature of the thing.

4. And hence it is further concluded that genus and difference, taken singly, are distinguished from the nature of the thing from the whole species, because they are compared to it as parts to a whole truly and in reality composed of them; but the whole is distinguished from the nature of the thing from each component, granted that it is not distinguished from all taken together and united; for it is distinguished at least as including something which the other does not include. Whence for this reason it is also commonly said that genus and difference, precisely taken in the notion of parts, cannot truly be predicated of the species, because a part is not predicated of the whole. And it is confirmed, first, for if in the thing man and animal were in no way distinguished, neither would horse and animal be; therefore neither could man and horse be distinguished, for things which are the same as one third thing are the same as each other; and whatever is of the essence of one will be of the essence of the other, and conversely; for, if man and animal are the same in the thing, whatever is of the essence of man will be of the essence of animal; and it will be similar in the horse; therefore the same will hold comparing man and horse among themselves; or certainly it will have to be confessed that something is of the essence of animal in man which is not in the horse, and conversely; from which it follows that animal is not said univocally nor according to the same notion of man and horse, but equivocally, or at most according to a certain analogy of proportionality. Finally it is confirmed by that reason often made, because diverse things cannot be similar and different according to altogether the same; but two species differ simply and essentially, and yet are similar in genus; therefore it cannot happen that genus and species are not in some way distinguished in the thing itself.

Various opinions are reported

5. In this matter there can be various ways of speaking. The first is that these grades are distinguished not in any way whatever from the nature of the thing, but altogether really, at least through the inclusion of some really distinct thing which is in one and not in the other. Jandun indicates this opinion, Metaphysics II, q. 9, and all those must hold the same who think that these generic and specific grades are taken from really distinct forms; for thence it follows that body signifies only the composite of matter and the form of corporeity, living the composite of body and vegetative soul, animal adds a really distinct sensitive soul, man the rational. But of the differences, rational and the like, this opinion would perhaps say that they express only the ultimate form as informing; whence also it comes about that it expresses something really distinct from the genus. And hence perhaps Durandus thought, In II, dist. 3, q. 1, that in simple things, such as angels and accidents or forms themselves, there cannot be proper differences, and consequently not a composition of genus and difference.

6. The second opinion is that these predicates are distinguished from the nature of the thing among themselves and from the composite itself, at least by the distinction which they call formal or modal. So Scotus holds, In II, dist. 3, q. 1, and Metaphysics VII, q. 16, and there Antonius Andreae, q. 7; for, although Scotus sometimes posits a real distinction between common and proper physical forms, as between the form of corporeity and the soul, for example, and then must necessarily say that between the grades taken from these forms there is a greater distinction than formal, according to the preceding opinion, nevertheless he does not think that that real distinction is formally necessary for distinguishing these grades, for in the same physically simple thing he admits true genus and difference and their composition; and therefore, speaking generally, he says that a formal distinction from the nature of the thing suffices and is at least necessary. But whether this formal distinction in Scotus is actual in the thing or only virtual or fundamental, and so coincides with the other which is called a distinction of reasoned reason, is not sufficiently evident, for he speaks variously, as we shall touch upon in the following disputation; now this opinion is to be treated by us in that sense in which it posits an actual distinction in the thing; and in that sense Ferrariensis seems to follow it, Contra Gentiles I, cc. 24 and 42; and Fonseca, Metaphysics II, c. 2, text 11, where he gathers it from the text of Aristotle, who denies that there can be a process to infinity in essential predicates, because, if they were distinguished only in thought, there would be no inconvenience in there being a process to infinity in them. Fonseca repeats the same, Book IV, c. 2, q. 4, sect. 3, and Book V, c. 7, q. 3, sect. 3, ad 2.

7. The third opinion, extremely contrary, can be this, that they are distinguished neither in the thing nor even by reason, but are altogether the same, although they are signified by diverse words. Which opinion can be attributed to the nominalists, in so far as they altogether deny that these universals are found in things; but it is scarcely credible that this opinion came into the mind of any philosopher, as the arguments made at the beginning at least conclude.

8. The true opinion, then, is that all these are distinguished by reason, some foundation being taken from the things themselves, yet that there is not some true and actual distinction, either real or from the nature of the thing, between all grades of this kind as they exist conjoined in reality. This is the opinion of St. Thomas, as is evident from I, q. 50, a. 4, ad 1; q. 76, a. 3, ad 4; and De ente et essentia, c. 4 and following; In Metaph. VII, lect. 4; and often elsewhere; and the Thomists commonly hold it: Hervaeus, Quodlibet I, q. 9; Capreolus, In I, dist. 8, q. 2, a. 3; Cajetan, Soncinas and Soto in the places cited in the preceding section; Gregory, In I, dist. 38; Gabriel and other nominalists. And since the affirmative part about the distinction of reason has been evidently proved by the arguments made and has no difficulty, nothing need be added about it; but the foundation of such a distinction will be declared in the solutions of the arguments, and more in the following section.

The true opinion is declared

9. In order that we may prove the other, negative part, it is to be noticed that, when we treat of the distinction of these grades, of genus, difference and species, they can be compared in four ways: first, as they are found in reality in diverse things or species; as if the animal which is in man is compared with the species of lion or horse, or if animal as it is in the lion is compared to the difference rational, for example, or another similar one; and this comparison is outside the matter and irrelevant, for in this way it is evident that the generic notion existing in the thing can be really distinguished from some difference or species of it; because in diverse species the formal unity of the genus itself is multiplied according to the thing; just as we said above that specific formal unity, as it exists in the thing, is multiplied in number in the individuals. But whether the genus, as it is in reality in one species, is distinguished from another species or its difference not only really but also essentially and quidditatively, perhaps pertains to the mode of speaking and depends on the proofs of this opinion, and is explained in the solutions of the arguments.

10. Secondly, they can be compared according to themselves, abstracting from existence both in things and in the intellect, in the way in which above we cited some saying that the nature according to itself, that is, barely and solitarily taken, is universal, as it precedes even every work of the intellect; for in the same sense they seem to think that quidditative predicates are distinguished among themselves from the nature of the thing. Because, if animal, for example, of itself and before every intellect has a positive aptitude to various differences and a unity of prescission of itself common to many species, it necessarily follows that it has from its nature some distinction from all the differences by which it can be divided and from the species to which it can be contracted. But, the things being posited which we have said of the notion of the universal, this comparison has no place; for we have shown that there is no state in which the common nature, whatever it may be, can have some unity of prescission, the intellect being excluded, if as existing in things themselves it cannot have it. Because the nature outside the intellect can have only a twofold state, namely of actual existence and of possibility, nor can another intermediate state be feigned or thought out; but the nature as possible is not otherwise prescinded or distinguished from possible differences or species than the existing nature from existing differences or species; nor is there some possible nature distinct from its inferior individuals or species, if existing in the thing it can never be distinct; because the existing and the possible nature are not one thing and another, but the same considered in diverse states; this comparison, therefore, can in truth be none which has a foundation in the thing.

11. Thirdly, genus and difference can be compared both among themselves and with the species which they compose, as they are in the intellect precisely and abstractly conceiving each of them; and in this way it is evident that they are distinguished by reason, as we have said; but whether they are distinguished by more than reason cannot (which is very much to be noted for solving the arguments made at the beginning) be sufficiently gathered from this comparison alone, unless in the things themselves some other sign of greater distinction is found. It is proved, because this is the power of the intellect, that it prescinds and abstracts things which in the thing are not actually distinct or prescinded; therefore, from the fact that some things as presented to the mind are distinguished by reason, no distinction between them in the thing can be gathered; because to be so distinguished by reason is nothing other than to be presented to distinct concepts of the intellect and to be conceived in a diverse way or under a diverse relationship, all of which can stand without distinction in the thing. And this can be confirmed from what we said above of the objective concept of being, how it is prescinded through the intellect and according to the thing undistinguished from all inferior beings; for the reasons made there proceed in the same way here, and we shall immediately touch upon them briefly.

12. In the fourth way, then, these can be compared as they exist in the thing in one and the same species and in one and the same individual of such a species; and in this sense this comparison is truly intended in the present question; and in the same sense we say that in Peter, for example, being sensitive is not distinguished from the nature of the thing from being rational, nor the grade of animal from the grade of man, and so of the rest.

13. The second note.—Where it is to be considered, secondly, that in the thing itself and in the same individual the generic grade can be understood to be distinguished from the specific in two ways: in one way, as the universal from the particular; in another way, as individual from individual at least formally distinct from the nature of the thing. The former mode of distinction would have place if it were true that universals existing in reality are actually and from the nature of the thing distinguished from the individuals in which they exist; and in this way Scotus seems to have proceeded and consequently spoken, because animal, for example, does not descend to individuals except by means of the species; and therefore, if we once admit that the specific nature as such is distinct from the nature of the thing from the difference by which it is contracted to individuals, by equal reason, and consistently enough, it will be said that the generic nature is in the same way distinguished from the differential grade prior in nature to its being contracted to individuals. But this mode of distinction has no place, the things being supposed which we said against Scotus of the universality of the nature, that it is in no way actually in things nor in the nature existing in individuals, but only as abstracted through the intellect. For if the nature in the thing does not have universality, then neither does it have the universality of genus, nor of difference, nor of species; therefore these cannot be distinguished in the thing as one universal from another or from its inferior. And it is confirmed, because the reasons by which it was shown above that the universal is not distinguished in the thing from the singular prove equally of any universal whatever, whether generic or specific, with respect to that singular in which it exists; therefore in the thing there can be no distinction between one inferior and superior grade universally taken, since in reality they are not distinguished from singulars.

14. There remains, then, only the other mode of distinction to be examined, which being excluded, it will be sufficiently shown that there is no distinction from the nature of the thing between these grades. And in this there is some difference and somewhat greater difficulty in the present question than in that treated above about the distinction of the universal from the individual difference; for, the individual difference being excluded, the singular and individual thing does not remain, and therefore neither can there remain an existing thing which would be distinguished in the thing from such a difference; but in the present case, the specific difference being excluded, the generic grade can be understood not only in the universal but also in the individual and really existing; for Peter, for example, is not only this man, but also this animal and this rational; and therefore, the specific difference being excluded through the intellect, the generic grade can still be understood as existing in the individual and singular, and accordingly the question still has place how in the individual this animal and this man, or this rational, are distinguished; that, then, they are not distinguished in the thing must be proved otherwise than from universality.

The first proof of the true opinion

15. It can be proved, then, first from individuation, because in one individual the individual difference is altogether one and the same and most simple, contracting proximately and immediately the lowest species and, with it and through it, consequently determining all the superior grades; therefore those grades cannot be distinguished among themselves more than each is distinguished from its individual difference; but none of them is distinguished from the nature of the thing from its individual difference, as has been proved; therefore neither are they distinguished among themselves from the nature of the thing in the same individual. The first antecedent is common among the dialecticians and metaphysicians, as Fonseca reports and declares at length, Book V, c. 28, q. 14, sect. 3, where he shows that the genus does not regard individuals except by means of the species. And the reason is, first, because the generic notion precisely taken is indifferent and as it were in essential potency to be determined by the specific difference, and therefore, until it is understood to be determined in this way, it is not proximately capable of individuation. Secondly, because the order between the generic, specific and individual difference is no less essential than between the superior essential differences, more and less universal, down to the specific; but body, for example, is not apt to be contracted by the difference of animal except by means of the difference of living, nor vegetative by the difference of rational except by means of the difference of sentient; therefore neither is animal determinable by the individual difference of this animal, for example Peter, except by means of the difference of man or rational; there is, therefore, one altogether indivisible individual difference, which, by contracting man to this man, at the same time contracts animal to this animal, and so of the other superior predicates. Whence I argue, thirdly, because such an individual difference, single and indivisible, suffices to determine in the singular the whole and integral essence of the thing, as it includes all the specific, generic or superior predicates which can be abstracted or thought out in it; therefore it would be superfluous to feign several metaphysical differences of this kind in the same individual. And it is confirmed from a sign; for this animal, for example, which is Peter, is altogether intrinsically and as it were essentially determined to be Peter; and therefore it is altogether repugnant to understand this individual of animal outside this individual of man; and the same holds of the other superior predicates; it is therefore a sign that animal is not determined immediately and according to itself to this individual of animal, but in so far as it is determined to the being of man; therefore the same individual difference is determined to the being of this man and of this animal.

16. Finally it is confirmed, for the individual thing as such is understood to be proximately capable of existence; for the universal as such, that is, in its universality, cannot exist; and therefore, the more universal a predicate is understood to be, the more as such it is conceived to be removed from existence; as, for example, substance in common is not understood to be apt to exist unless it is determined to material or immaterial; and the reason is the same of the whole series of general predicates down to the lowest species, which, contracted to its individual, is proximately capable of existence; therefore, just as no individual can exist unless it is in some lowest species, as is most certain (especially the false opinion of the real distinction of several substantial forms, essentially subordinated in the same composite, being excluded), so no generic notion is understood to be determined to its proper individual except as contracted and determined to some species. Which indeed in things, especially simple ones, both integral and partial, seems most evident of itself; for who would feign or conceive in the mind that Michael, for example, is through one thing this substance, this spirit and this angel? or that the rational soul of Peter is through one thing this soul and this rational soul, and so of others? Indeed in some cases this individual cannot even sufficiently be conceived by the abstraction of the mind as existing under the generic notion and not under some specific one; as, for example, this existing substance, this body or this spirit not being understood; let it be established, then, that all the essential attributes in one and the same individual are individuated by a single singular difference in the ultimate specific notion. But from this it is openly concluded (what we inferred in the first consequence) that the essential attributes in the same individual cannot be distinguished among themselves more than from the individual difference, because that is one and indivisible; therefore the things which are individuated by it cannot be distinguished as two individuals distinct from the nature of the thing, because in distinct individuals, in the way in which they are distinct, distinct individual differences must also be found; again, things which are altogether the same from the nature of the thing with the same individual and indivisible difference cannot be distinguished individually among themselves; therefore they are in no way distinguished from the nature of the thing, because, as has been proved, a distinction from the nature of the thing cannot intervene except between individual and singular things as such.

The second proof

17. Secondly the assertion posited is proved, because in one individual, for example Peter, to be this animal and to be this man come from the same physical principle, namely from this soul, as is self-evident and will be declared in the following section; but in this soul, for example of Peter, to be rational, sensitive and vegetative (whether formally or eminently) are not grades distinct from the nature of the thing; therefore neither are the grades of man and animal in any way distinguished in Peter. The consequence is evident, because we rightly conclude that this animal is not really distinguished from the man himself because this soul which gives the being of animal is not really distinct from that which gives the being of this man; therefore in the same way it is concluded that it is not distinguished from the nature of the thing. You will say that this argument proceeds from things equally unknown; for whoever posits this distinction in the composite posits it also in the form and in any other thing whatever, even if it is physically simple. The answer is that, granted that it must be spoken so consistently in that opinion, nevertheless the argument and the difficulty are deservedly referred back to the roots of these grades and to simple physical entities, because in them it can appear more clearly how superfluously and without cause this distinction is feigned, since there is no sufficient indication of it in the foundation and root of such grades. Which is evident thus: for the rational soul, for example, is in the thing one simple form; which, if it is considered as the efficient principle of all the operations which are in man, is understood to be one eminent and as it were universal principle of them; nor is it necessary to feign in it various entities or real modes distinct from the nature of the thing through which it would be the principal and radical principle of such operations; otherwise also in the form or light of the sun, in so far as it can be the universal principle of several actions, various grades or modes of being distinct from the nature of the thing would have to be feigned. And similarly one would have to philosophize in every general principle of several actions or effects, which is foreign to all reason and right conception, because things which are distinct in inferiors are united in a superior principle. The rational soul, therefore, through its entity, in the thing altogether the same and simple, is the radical principle of all human operations without any actual distinction which is in it as it has the notion of such a principle, although through inadequate concepts it can be conceived by us in many ways, and so be distinguished by reason in order to various operations. Therefore in the same way the same soul in the genus of formal cause confers on man all the grades of living, animal and man according to altogether the same reality, without any actual distinction which is found in it from the nature of the thing. The consequence is evident, both because the reason is the same of the soul considered in one and in another genus of cause; and also because by the same thing by which the soul is the radical principle of operations it is the principle formally constituting the operating thing. Indeed these grades are distinguished by us in the soul in no other way than in order to operations. Whence, if in order to them a distinction from the nature of the thing is not necessary in their principle, neither will it be necessary in the notion of informing.

18. But if in these grades which are taken in order to diverse operations a distinction from the nature of the thing is not necessary, much less will it be necessary in other superior or inferior genera or differences, such as, for example, the notion of body or of substance; or, if we speak of forms, the notion of substantial form or of form of body; for, by the very fact that something is a form of matter actuating its substantial potentiality, it is a substantial form and is also a form of body; but this is inseparable and indistinguishable from the nature of the thing from any form whatever actuating matter and composing with it one substantial composite. Similarly the inferior genera, such as the notion of brute under animal and others of this kind, can be distinguished less than the aforesaid grades in man; for if in the soul of man as it is the principle of various operations a distinction from the nature of the thing is not found, much less will it be able to be found in the soul of the brute, for example, in order to sensitive operations effected in such a way in that grade and order.

The third proof

19. Thirdly there is an excellent a priori reason, because this abstraction of genera and species, in order to be made by the intellect, has a sufficient foundation both in it and in things without any actual distinction which precedes in the things themselves; therefore such a distinction is not to be asserted. The consequence is proved, because the whole reason for introducing this distinction was taken from our mode of conceiving, and consequently from the mode of speaking founded in the mode of conceiving; therefore, if on this account that distinction is not necessary, neither is it to be believed, because real distinctions, or those from the nature of the thing, are not to be multiplied without foundation. But the first antecedent, although it has been proved in treating of the concept of being and of the identity between the common and the individual nature, is here briefly declared and proved. Because, in order that the intellect form and prescind those concepts, on the side of things the agreement and likeness of them among themselves, more or less perfect, with some dissimilitude and disagreement, suffices; but on the side of the intellect it suffices that it can conceive that in which things agree after the manner of one, by conceiving it precisely; but all this can come about without an actual distinction of grades which is in the thing itself; therefore. The minor is proved by the examples adduced above; for two men agree among themselves in the notion of man and are distinguished as they are individuals, without a distinction in the thing between the common notion and the individual difference. Likewise God and the creature agree in the notion of real being and differ in the notion of such being, without a distinction between the common and the proper notion, neither on the side of God, as is certain, nor on the side of the creature, because no grade can be prescinded in the creature, if it is positive and real, which does not have that agreement with God in the notion of being. These examples, therefore, declare that altogether the same thing can be the principle and foundation of agreement and difference with another on account of greater or lesser likeness with it, without any actual distinction which precedes in the things themselves.

20. Which holds true not only in analogous agreement, as some indicate, but also in univocal, as the example of specific agreement and individual difference sufficiently declares; and other examples can be adduced of more universal or generic agreements; for the common sense, for example, agrees with sight in the perception of colour, and thence a common concept can easily be abstracted; but with hearing it agrees in the perception of sound, and thence another concept can be abstracted; but no one will say that the power of perceiving sound and colour is distinguished from the nature of the thing in the common sense itself. It is similar with the light of the sun, in so far as it agrees with heat in effecting heat and with dryness in drying. Likewise qualities intermediate between contrary extremes, as the colour green or red between white and black, and liberality between avarice and prodigality, have a certain agreement and dissimilitude with the extremes; for liberality, compared to avarice, differs from it and agrees with prodigality in the power and propensity of pouring itself out and communicating; but compared to prodigality, it differs from it in moderation and agrees with avarice in retaining; but it would be vain to feign in liberality various grades or real modes distinct from the nature of the thing on account of these comparisons and conceptions of our intellect, which (if the matter is attentively considered) can almost be multiplied to infinity; and scarcely can differences so simple be thought out that the intellect could not divide them, finding in them agreement and difference with other things; as in man, in so far as he is rational, it finds agreement with the angel in understanding and difference in the mode of understanding; and so of others. From these things, then, it is sufficiently evident that concepts of the intellect of this kind are not sufficient signs of the actual distinction of things.

Solution of the arguments

21. The composition of genus and difference is a composition of reason.—To the first argument posited at the beginning the answer is that the composition of genus and difference is not a real composition, but only of reason; because, as the argument well proves, without a distinction from the nature of the thing neither can a true composition, and one which is in the thing, be understood; because composition is nothing other than the union of distinct things; where, therefore, there is no distinction in the thing, neither can there be composition; this, therefore, is a composition of reason. But this composition is said not to be altogether feigned through reason, not because it actually precedes in the thing, but because in the thing there is a foundation for the intellect to be able to conceive one notion as potential and prescinded from the other, and the other as actual and determining the former; and so properly the composition is only in concepts, but in the thing only by extrinsic denomination from the concepts of the mind; and in this way it is said to be a composition of reason. Wherefore such a composition is not repugnant to God on account of simplicity alone, as I shall say below, but also by reason of the divine illimitation and eminence. For first of all on this account he cannot have univocal agreement with the creature, and consequently not generic either. Next, in God no common notion can be so abstracted and prescinded that it is not included in every proper and particular notion, on account of the supreme illimitation and simplicity of God, which is also repugnant to the composition of genus and difference.

22. How far the definition and its parts are commensurate with the thing and its parts.—To the confirmation the answer is that the parts of the definition are not properly said to signify the parts of the thing, but to have a certain proportion with the parts of the thing, as St. Thomas expounds, In Metaph. VII, lect. 9, because genus and difference are related after the manner of matter and form, which are the parts of the thing from which on this account genus and difference are said to be taken, as we shall explain more fully in the following section. Next it is said that the definition is a work of the intellect and necessarily requires some true and proper composition of distinct concepts, as the definition uttered in speech must consist of distinct partial words; for it explains distinctly the nature of the thing, which cannot be done by us by one word or by one simple concept; and by this reason it is said to consist of parts; it is not, however, necessary that the individual parts of the definition explain individual parts of the thing defined distinct in the thing, but each can express the whole nature or entity of the thing defined; yet one expresses it confusedly and under some common and potential notion, but another under a more determinate and proper notion; and such diverse notions can be called parts of the thing defined not according to the thing but according to reason only; for the thing defined as defined expresses a denomination of reason.

23. To the second the answer is that genus and difference express essences or essential notions diverse according to reason, not according to the thing; and in this way the genus is said to be outside the notion of the difference and the difference also outside the notion of the genus; for the notion of each is so conceived and prescinded in the mind that according to that prescission and abstraction neither is formally included in the other; for which it is not necessary that they be distinguished in the thing itself in one and the same thing, but on the side of the genus it is enough that its notion, as it corresponds to such a conception, is not intrinsically constituted by its dividing difference, and consequently that it can be found in the thing without such a difference; but on the side of the difference, in order that the genus be said to be outside its notion, it is enough that in its precise objective concept the objective concept of the genus is not included, but the difference is conceived as the act of the genus altogether distinct by reason. And this too is enough for genus and difference to be said to be compared as potency and essential act, not according to the thing but according to reason only; for as the composition is, such must the act and potency be; but this composition is of reason, as we have said; in the same way, therefore, one per se is said to be composed of genus and difference according to reason and not according to the thing; and therefore such a composite is most of all one per se, because the components are one in the thing, and according to reason they are per se compared and subordinated. And in this sense St. Thomas said, In Metaph. VII, lect. 12, that the difference is not added to the genus as an essence diverse from it, but as contained in it implicitly, as the determinate is contained in the indeterminate; and for this cause one per se is composed of them.

24. To the reason the answer is that we can speak of genus and difference in two ways. First, as they exist in reality; secondly, as they are prescinded through the intellect. In the former way, since genus and difference are not distinguished in the thing in each species, genus and difference have the same essence as the species, although it is signified diversely through the concepts or words signifying genus and difference, as St. Thomas, just cited, said. And in this way the genus, as it is in the thing, actually includes the opposite differences, as it is in diverse species; in which way equivocations are said to lie hidden in the genus. And so also Aristotle said, Metaphysics X, c. 11, text 24, that the genus, as existing in one species, is diverse from itself as it is in another. Nor does it stand in the way that those differences are opposed, because the genus so considered does not have real unity, but its formal unity is multiplied in diverse species, and therefore in them it can be actuated by opposite differences, or rather be identified with them. But in the second way, and more properly and usually, we speak of genus and difference as they underlie our abstract and prescinded concepts; and so only that is said to be of the essence of each which is per se necessary for the formal notion and constitution of the thing so conceived; and in this way (as has been said) neither are the dividing differences of the essence of the genus, nor the genus of the essence of the differences; yet this whole distinction and prescission is through the operation of the intellect, to which the essence expresses a relationship, or which it involves, when it is signified by the names of genus and difference.

25. The third argument, and all the things which are indicated in it, have often been solved above, for the same arguments are made in the species with respect to individuals and in being with respect to its inferiors. I say, then, that the genus, as it is in reality conjoined with its difference, is altogether inseparable from it; and from such a difference we say that it is not distinguished in the thing itself; but that the genus, as it is in one species, is separable in the thing from the difference of another species is no argument that in one and the same species genus and difference are distinguished, because the genus, as it is in the thing in one species and in another, is not really one and the same, but by reason and abstraction only; therefore only a distinction of reason is included, of which there is in the thing itself some foundation, namely some incomplete and imperfect likeness of diverse natures, which can be in the thing without actual distinction, as has been declared. That expression, therefore, that the difference contracts the genus or actuates it, expresses order to our concepts, and therefore a distinction of reason suffices for its truth and propriety.

26. The fourth argument touches a difficulty which demands the following section; but the other arguments which were brought forward to show a distinction from the nature of the thing between genus and species among themselves, and difference and species among themselves, have an easy solution from what has been said. Whence to the first the answer is that genus and difference are not compared to the species as parts distinct from the nature of the thing, but only by reason. And this is enough that genus or difference, taken with prescission, cannot be predicated of the species, as has been declared. To the first confirmation too the solution is evident from what has been said; for, although in man animal is the same as man and in the horse is the same as the horse, it does not follow that man and horse are the same among themselves, because they are not really one animal, but only have likeness in being animal, by reason of which they agree in one concept of animal; and this is enough that animal be univocal and be said of each according to the same conceived notion, although according to the thing animal has another real essence in man than in the horse, and conversely. To the last confirmation the assumption is denied; for nothing is repugnant, as has also often been shown, that a thing altogether the same and without any distinction which is in it from the nature of the thing should found likeness and difference with another; because they can be assimilated imperfectly and only in a certain respect, yet simply differ.