Commentaria in Summam contra Gentiles, Liber I

Second, it is shown that in God there is no actual composition of genus and difference¹. And this conclusion is set down: God is in no genus.

Concerning which conclusion Saint Thomas does three things: first, he proves it; second, he draws certain corollaries from it²; third, he resolves a certain objection³.

I. As to the first, he argues first as follows⁴: In God there is nothing by which the nature is designated to a species. Therefore it is not in a genus. — The antecedent is clear from the preceding chapter. — The consequence is proved thus: because nothing is in a genus that is not in some species of it. This is to be understood of those things that are complete in their nature and directly so; not, however, of those that are contained under a genus only by reduction.

But the antecedent of this argument seems not to be had from the preceding chapter. For there it was shown that the divine esse cannot be designated essentially by something superadded. From this, however, it is not obtained that in God there is nothing determinable and nothing determining: just as from the fact that humanity is not essentially limitable and contractible by another formal difference, it does not follow that in humanity there is not, if considered formally, a nature contractible in itself and a contracting nature.

It is answered that, from the same reasons by which it was proved that nothing can be added to the divine esse that would designate it essentially, it is evident that in God there is nothing that has the character of a difference designating essentially. For that which would be designated by it would not be of itself necessary being: since in order to be in act it would need that difference, as was argued in the first reason. — And it would be in potency with respect to it: as was assumed in the second reason. — That difference itself would be a part of the essence formally taken: as the third reason concluded. — Likewise, whatever is in act in God is formally identical with every nature that is in God, if the things that are in God are considered in themselves: since all things are the pure esse itself. Therefore nothing can be added to anything existing in God that would be outside its character: as the fourth reason argued. — Implicitly, therefore, once it was shown that the divine esse does not admit essential limitation, it was also shown that there is nothing in God that has the character of a difference essentially limiting.

II. Second. God is not in the genus of accident: because an accident cannot be first being and first cause. Nor in the genus of substance: because substance, which is a genus, is not its own esse; otherwise every substance would be its own esse, since the ratio of a genus is preserved in all things contained under that genus⁵, and thus substance would not be caused by another; but God is his own esse. Therefore God is not in a genus.

To make this argument clear, it must be considered that something has the character of being caused by another because it receives its esse from that other; for to cause, as was said above⁶, is to make something be in act. Therefore, where it is posited that a thing's esse does not belong to it from another, it follows that the thing itself is not caused. But from the fact that it is posited that the substance of a thing is not distinguished from its esse, it must be held that esse does not belong to the thing through any other efficient cause: for the essence of a thing belongs to it of itself, and not through a productive cause. For there is no cause that makes a man be a man, or an animal, or a substance, since propositions of this first kind are of eternal truth, whether the thing is brought into being or not. And if Saint Thomas is found to say at some pointas in De Veritate, q. xxi, a. 5, ad 5, that the creature is from God according to its very essence, this must be understood to mean that he produces the creature's essence itself into esse, not that he makes the creature's essence belong to itself, as if he made a man be a man. It follows, therefore, that if the substance were its own esse, the substance would not be caused: because it would receive esse from no other, just as it would not receive its essence.

III. Third. Whatever is in a genus differs in esse from all the other things that are in that genus. But it agrees with them in the quiddity of the genus. Therefore, in every being existing in a genus, esse is other than the quiddity of the genus. Therefore God is not in a genus. — The antecedent is proved as to its first part, because a genus is predicated of many things; and some things, agreeing in one common quiddity, are many precisely because they have distinct esse. As to the second part it is proved, because the genus is predicated in quid of all the species. — The first consequence is evident: for the same thing cannot be both the principle of agreement and of distinction with respect to the same thing. — The second is also evident: because in God esse is not other than His quiddity.

Concerning this argument it must be noted that from the fact that species agree in the quiddity of the genus, but differ in esse, both quidditative and of actual existence, it does not formally follow that those things which are in a genus have an esse really distinct from their quiddity, but only formally: just as from the fact that species of animal agree in the quiddity of animal, but are distinguished by the differences of animal, it does not follow that the quiddity of the genus is really distinguished from the difference, but only formally. And this suffices for the argument of Saint Thomas: for in God esse is not only not really distinguished from essence, but not even formally. For if the divine essence were conceived, and all things that are in it, as they are in themselves, there would be one and indivisible account of all things, on account of the supreme simplicity and purity of the divine nature. But in order to intimate this formal distinction of essence and esse in a thing existing in a genus, Saint Thomas said, The esse of anything existing in a genus is beyond its quiddity, but he did not say, it is really distinct from the quiddity: — although it is also true that it is really distinguished, as will be proved by other arguments in Book Two ⁷.

IV. But concerning what has been said a doubt arises. For someone might say that, just as genus signifies one common nature according to reason, insofar as it is abstracted by the intellect from the differentiae, so too the esse of that generic quiddity is one common thing according to reason, considered through abstraction from all limiting principles, and it is identical with that quiddity. And just as the quiddity of the genus is multiplied really in several species through the differentiae, since the nature of the genus in one species is diverse from the nature of the genus in another, as is said in X Metaph., text. 24 ⁸, so too the esse of that quiddity is diversified in the different species. And thus no greater unity remains in the quiddity than in the esse: but, just as the quiddity of the genus remains one according to reason while being multiplied really, so too the esse of several species remains one according to reason, while being multiple according to the thing.

2. For the evidence of this, it must be considered that esse does not belong to a genus except as it is limited in the inferiors. Therefore the comparison between the quiddity of the genus and its esse is considered according as the quiddity of the genus is found in its species. For there is no esse by which animal exists in nature separated from all species: but there is indeed an esse by which this animal which is man exists, and by which this animal which is horse exists, and so on for the others.

It must be noted, secondly, that esse, although it possesses a certain community of account, inasmuch as every esse is said to be the actuality of existing, is nevertheless not common, as we said above ⁹, in the manner of a genus. For the esse of an animal does not signify one nature found in all animals' esse, abstractible from them by the intellect and contractible by some difference, as animal does; for since it signifies the actuality of all actualities, it cannot be limited by anything more formal and more actual. But its community is a community in the manner of a form, which is limited by what receives it: for the esse of a man is distinguished from the esse of a horse because this is the actuality of this one, that of that one. On this account, just as one receiver of it is constituted by one generic difference and another by another, so too the formal account of actual existence is different in one species of a genus and different in another species. And therefore, just as with the formal unity of a genus there stands, in all its species, a plurality of differences and of specific esse, so also with that unity of the generic quiddity there stands a formal plurality of esse itself as existing existence.

3. To the doubt, therefore, it is said, first, that the genus is multiplied really in the species and with respect to the quidditative esse of the species, but not formally nor with respect to its own proper quidditative esse. For although the nature of the genus in one thing is really diverse from the nature of the genus in another, it is nevertheless not formally diverse: for the nature of animal in all animals is an animate sensible substance.

It is said second, that the esse of actual existence of a genus does not remain formally the same in all things: since it does not signify one nature abstractible by the intellect from all things, but rather as by diverse differences there is constituted a diverse subject receptive of that esse. Thus the ratio of actual existence is diversified together with its real diversity.

It is said third that, although these esse's are one in some common concept formed by the intellect, inasmuch as they are one by a certain proportionality—just as the esse of a lion is related to the lion, so the esse of a horse to the horse—nevertheless the force of the argument is not thereby removed. For this proposition is always true: That which is formally one in many things is formally distinguished from that which is multiplied in them; otherwise one and many would be the same. Therefore, if the quiddity of the genus is one in the species, while the esse's are many in those same species (although perhaps they are one according to some concept of the intellect), then the very quiddity of the genus is formally distinguished from esse. — Nor does it avail to say that esse itself remains one in many things according to a concept: for, as has been shown, on the side of the thing there is nothing one and common to all those esse's, just as for all animals there is not one common nature abstractible from them by the intellect.

From this, moreover, it further follows that they are also really distinct, as the Most Reverend Cardinal of Saint Sixtus ingeniously deduces in the book On Being and Essence ¹⁰: namely, because the real distinction of esse from essence is the cause of the formal distinction between them, just as the real identity of these is the cause of their formal identity. For the following argument holds: Essence is really the same as esse; therefore it is not determined to any genus: because essence does not beg esse in act from another formally, whereas the nature of a genus is limited by the difference. Therefore it is pure esse: because esse not determined to a genus is pure esse. Therefore esse belongs to its reason: because esse belongs to the formal reason of pure esse. Therefore, from first to last, essence is really the same as esse. Therefore essence and esse are formally the same.

V. Fourth. God is his own esse. Therefore he is not placed in a genus. — The consequence is proved. Because nothing could be a genus of him except being, since each thing is placed in a genus by the account of its quiddity; but esse is signified only through being. Yet being cannot be a genus, as is said in III Metaphysics, text 10 ¹¹. Therefore, etc. — That being cannot be a genus, the Philosopher proves there by this argument. Every genus is contracted to a species by some difference. This difference is not part of the account of the genus itself, but is outside that which is understood in the account of the genus; for if the genus were part of the account of the difference, it would be posited twice in the definition of the species. But nothing can be outside that which is understood by being, if being is included in the understanding of the things of which it is predicated. Therefore being cannot be a genus.

To make this proposition evident, Each thing is placed in a genus by reason of its quiddity, it must be known that, since in an existing thing there are quiddity and esse, nothing in it is placed in a genus by reason of its esse itself, but only by reason of its quiddity—namely because its quiddity is contained in the genus potentialiter and the genus is predicated of it essentialiter. Hence, since everything contained directly in a genus is a species of it, to be contained in a genus by reason of quiddity is nothing other than to be a species of the genus through one's quiddity; not through one's esse, where esse is distinct from quiddity.

It must also be noted, concerning that proposition, the difference must be outside what is understood in the account of the genus, that what is understood in the account of the genus is the very quiddity and nature of the genus as signified by its definition. Therefore, to be outside what is understood in the account of the genus is to be outside the essence and quiddity of the genus. Now this can be so in two ways. In one way, because that thing does not enter into the essence and quiddity of the genus: and this belongs not only to the difference, but also to the species. In another way, because neither does it itself enter into the quiddity of the genus, nor does the quiddity of the genus enter into its quiddity. And it is in this way that the difference is understood to be outside the quiddity of the genus; otherwise it would be posited twice in the definition of the species, once per se and once as included in the difference.

VI. But a doubt arises ¹². For being here seems to be taken as signifying actual existence: as is clear from the intention of St. Thomas, who holds that if God were in a genus, being would have to be its genus, because the quiddity of God is esse, namely actual existence, and being signifies esse itself. Now it is false that being so understood is predicated essentially of all things, as St. Thomas seems to suppose, and that nothing exists outside the ratio of being; for, according to him, it is thus predicated essentially of God alone. For the being that is predicated essentially is the being that signifies the essence of a thing, which is also divided into the ten predicaments, as is said in V Metaph.¹³; but not the being that signifies esse. Therefore either a falsehood is assumed, or the fallacy of equivocation is committed, when being is first taken participially and afterwards nominally.

VII. For the solution of this doubt, since the whole difficulty consists in the meaning of the term "being" (ens), it must be considered that, although "being," taken both nominally and participially, imports esse—for in either way "being" signifies that which has esse—nevertheless it is imported in one way differently than in the other. For if it is taken participially, as it is absolutely the same as "existing," esse is imported as its principal and formal signification, because it is the abstract of this concrete "being"; but that which has esse is imported secondarily, as the receiver of esse; just as "white" first and formally imports whiteness, which is its abstract, and secondarily imports the subject, because it signifies that very whiteness by way of something inhering in another. — But if it is taken nominally, then esse is not its abstract, but essence. Therefore its principal signification is not esse, but essence; and esse is imported through it as that from which the name is imposed; just as if a stone were said to be that which strikes the foot, the striking of the foot would be imported secondarily, as that from which the name is imposed, while its essence would be imported as the principal signification. This is clear from St. Thomas on Metaphysics X, in his exposition of text 8 ¹⁴, where he says that being divided through the ten predicaments signifies the very natures of the ten genera, according as they are in act or in potency.

2. It is said, therefore, first, that being divided into the ten categories is being taken nominally, that is, that which signifies essence first, as the thing signified, and secondarily esse, as that from which the name itself is imposed. It is said, second, that this is what is predicated essentially of all things, and which the Philosopher proves not to be a genus: but not being taken participially, whose principal signification is esse, as its abstract.

The first of these is clear from St. Thomas, Ver., q. xxi, a. 4, ad 4, where he speaks, as the first article of that question makes clear, of being divided into the ten categories. For there, laying down the rule that in general forms the concrete is predicated of the abstract, he shows this inductively, saying: "For we say that essence is a being, and goodness is good, and unity is one, and so on with the rest," where it is evident that he takes essence as the abstract and as the first and formal signification of being. In the first article, ad 1, he also says that, since "being" is said absolutely, while "good" superadds the relation of a final cause, the very essence of a thing considered absolutely suffices for something to be called a being by means of it. Likewise in the second Quodlibet, q. ii, a. 1 ¹⁵, he holds that being, insofar as it signifies the thing to which esse belongs, signifies the essence of the thing and is divided into ten genera, although, insofar as it signifies esse, it is an accidental predicate, as he gives us to understand.

But the second is proved, because Saint Thomas holds that esse in every creature is really distinct from the essence, and that it is not perfectly included within the concept of any creature, as is clear from Ver., q. 10, a. 12, and elsewhere. For thus it is evident that that which signifies esse as its primary signification cannot be predicated of a creature essentially; and consequently it is not that being of which the Philosopher proves that it is not a genus on this ground, namely because it is predicated of all things.

VIII. But this determination seems to be opposed, because St. Thomas seems to hold, in the First Part, q. 5 and 6, and in De Veritate, q. 21, that good—which is also divided into the ten categories, as is said in Ethics I¹⁶—is convertible with being taken participially, not nominally. This is clear from two points.

First, from what he says: since good and being are convertible, as a thing is a being, so it is good; but it is not a being by essence; therefore neither is it good. For in this argument, "being" must be taken participially, because this is precisely what is denied to belong to the thing by essence, on the ground that esse is really distinct from every created essence. Therefore the being that is convertible with good and divided into the ten categories is being taken participially.

Second, from what he says, that that by which a thing is formally good is not being. This statement is false when taken of ens taken nominally: because the esse of actual existence, by which a thing is a being and is good, is a being nominally.

2. To these things it is said first, in general, that they proceed from a false foundation: namely, that ens, when taken nominally, does not signify esse, but only when taken participially. This is most false: for in both ways it signifies that which has esse, as we said above ¹⁷. But it is true that, when taken nominally, it imports esse secondarily and as that from which the name is imposed; whereas when taken participially, it signifies esse not only as that from which the name is imposed, but also as the thing principally signified; for it is evident in the doctrine of St. Thomas that that from which a name is imposed and that to which it is imposed are in some cases the same ¹⁸. From which it follows that, taking ens nominally, something can be said to be ens by participation by reason of the secondary signified and of that from which the name is imposed, even though by reason of the primary signified it is not ens by participation but by essence.

It must be noted, however, that it is not the same to speak of being in act insofar as being is divided into being in act and being in potency, and of being taken participially. For being in act, which divides being, signifies essence first and formally, just as does the being that is divided; but it signifies that essence as it stands under the esse of actual existence, whereby it differs from being in potency, which signifies essence without actual esse. And therefore being in act secondarily signifies esse. But being taken participially, which is the same as an existing thing, as was said ¹⁹, signifies first and formally the esse itself, but secondarily the very essence to which esse belongs in its own way. Hence, although St. Thomas holds that good is convertible with being in act, he nevertheless does not hold that it is convertible with being taken participially with respect to its first and formal signification. And therefore the assumption in the objections is false.

3. To his first proof it is said that St. Thomas does not put forward that argument as it is adduced; but he says well in the Quaestiones de Veritate, q. 21, a. 5, ad 6: "In this way essence is called good just as it is a being. Hence, just as it has esse by participation, so also is it good by participation." In this argument, however, created essence is not said to be a being by participation by reason of its first and formal signification, but by reason of what is connoted, or by reason of that from which the name of being is imposed. For since created essence has esse distinct from itself and participated, being taken nominally in respect of that esse is predicated of it by participation. And thus it is false that in that argument ens is taken participially and not nominally.

To the second, the solution is clear from St. Thomas's own words in the same place, where he says ²⁰ that esse is not called a being by means of some other esse, but because through it a thing is said to be. Esse, therefore, is not a being as that which has esse, even taking "being" nominally: but as that by which something has esse. For being taken nominally is said first of that which has esse; secondarily, however, also of that by which something is, as is evident from Ver., same question, a. 4, ad 4, and Prima, q. vi, a. 3, ad 3.

IX. To the principal doubt, then ²¹ it is said first that being is taken as signifying esse, not indeed as its principal signification, but as that from which the name is imposed. And such is being taken nominally. It is said second that, according to the intention of St. Thomas, it is not required that being signify esse in any other way than we have described. For since being signifies that to which esse belongs, and predicates the essence of any thing whatsoever; while in God the very essence is really identical with esse: nothing could be a genus of God unless it imported esse itself absolutely and without limitation, either primarily or secondarily. Such also is being taken nominally: for it imports esse absolutely in a secondary way, and quiddity principally. And thus in God it signifies the quiddity which is esse itself. It is said third that it is not false—indeed it is true—that being which signifies esse as that from which the name is imposed should be predicated essentially of things, with respect to its first and formal signification. But it is quite false that being taken participially, which signifies esse principally, is predicated essentially, and that nothing exists beyond its concept.

X. But two doubts remain. The first is that, if the good is convertible with being taken nominally, and the good is divided into the ten categories as it is identical with being, as is said in Prima, q. 5, a. ult., ad 1; then the good must be convertible with being divided into act and potency, since that is what is divided into the ten categories; but not with being in act alone. Yet the opposite of this was said ²².

It is answered to this that, just as common being is divided into the ten categories by act and potency, so too is being in act. Hence not only is being divided into potency and act, but also each genus of being: for in every genus something is as potency and something as act. Hence being in potency is divided into the ten categories, and likewise being in act. For some potency belongs to the genus of substance, and some to the genus of quality, and so on with the others; and likewise some act belongs to the genus of substance, and some to the genus of quality, and so on with the others. This is clear from what is found in the Commentator, III Physics, comment 9. Therefore this consequence is denied: The good, insofar as it is the same as being, is divided into the ten categories; therefore it is convertible with being divided by act and potency, but not with being in act. The reason is that not only common being is divided into the ten categories, but also being in act and being in potency.

XI. The second doubt is: If the good is converted with being taken nominally by an essential conversion — for St. Thomas understands these to be convertible when he posits that they are really the same, and that the good adds to being only a respect of reason — it follows that the goodness and the essence of a thing are really the same. But St. Thomas says in the Prima, q. 6, a. 3, ad 3, that the goodness of a created thing is not its very essence. Therefore, etc. — The consequence is proved: for from the opposite of the consequent the opposite of the antecedent is inferred. For if goodness, which is the formal significate of the good, is not the same as essence, which is the formal significate of being, it follows that the good adds something real to being. And thus they are not converted essentially.

2. For the clarification of this, it must first be considered that it is one thing to say being absolutely and another to say being in act. For being taken absolutely signifies only essence as that upon which the name is imposed; but esse signifies as that from which the name is imposed. Being in act, however, does not signify only essence, but also esse itself. Hence actual being (entitas in actu), which is the formal signification of being in act, says essence first, and secondarily connotes esse—not only as that from which the name is imposed, but also as the actuality of the essence.

It must be considered, second, that since the good and being in act are essentially convertible, it follows that just as being in act signifies formally essence and esse, so too the good must signify those same things. And likewise it must be that goodness, which is the formal significate of the good, includes those two, just as they are included by entity in act. And thus goodness does not signify only the essence of a thing, nor only esse, but essence under esse.

It must be considered, third, that just as being (ens) signifies essence as the foundation of existing, while esse signifies the actuality of existing and the complement of entity in act, so the good signifies essence as fundamental goodness, while esse signifies completive and determinative goodness.

3. To the doubt, therefore, it is said first that it supposes two falsehoods. One is that to say "being" absolutely is the same as to say "being in act." — The other, that the formal signification of being in act, with which good is convertible, is essence alone; when nevertheless, as was said, it includes both essence and esse.

It is said second, that the consequence is false, speaking of omnimodal identity. — To the proof, the assumption is denied. — To the proof of this, it is said that essence is not the total signification of being in act, but essence with esse. And therefore it does not follow that good adds something real above being in act with respect to its total signification, but only with respect to its partial signification. This, however, is not unfitting: for thus being in act itself adds above essence; since it signifies not only essence, but also esse. — It does not follow either that it is not convertible essentially with being in act: but that it is not convertible with its partial signification.

It is said third, that the saying of St. Thomas has truth in two ways. First, of total and complete goodness. For such goodness, since it includes essence and esse, is not altogether the same as the essence of a thing, although it is in some way the same: just as that which includes several things is the same as each of those which it includes, yet adds something above it. — Second, of completive and terminative goodness. For such goodness is not the same as the essence: because such goodness is esse; but in creatures esse and essence are distinguished. And when St. Thomas often says ²³ that the goodness of a thing is the act of being (actus essendi), this is understood not of complete and total goodness, but of completive and terminative goodness.

XII. Concerning this conditional statement, if being is of the intellect of those things of which it is predicated, it must be noted that Saint Thomas does not speak conditionally because he doubts that being is of the intellect, or of the essence, of the things of which it is predicated: for he holds elsewhere, as we have cited ²⁴, that being signifies the essences of things. But he uses this manner of speaking in order to remove the calumny by which someone might deny that being is predicated essentially. As if he were to say: Since being is the most universal of all and is predicated of all things, nothing can be that does not receive being within its own ratio, unless someone wished to deny that being is predicated essentially of things—which would be manifestly false.

2. But then a doubt arises. If being is of the intellect of those things of which it is predicated, then being will be placed in the definitions of things, since whatever is of the intellect of a thing is placed in its definition. Yet the Philosopher says the opposite in VIII Metaphysics, text 16 ²⁵.

It is answered that, since a definition is given in order to distinguish one thing from another, only that is placed in the definition of a thing by which the thing defined has some distinction from others. This, however, is only genus and difference, which signify something determinate; not being, in which all things agree. Therefore St. Thomas glosses Aristotle's proposition ²⁶ by saying that being is not placed in the definition as a genus. But on this I have written more fully in my annotations on Book II of the Posterior Analytics.

But what is assumed—that since everything that is of the intellect of something is placed in its definition—it is said to be true only of that which posits some determinate degree of it, by which it is distinguished from others. Such, however, is not being. Therefore it is not necessary that it be placed in the definition of things.

But Scotus holds, in I Sent., distinction III, question III, that being is not predicated of the ultimate differences formally, but only identically. But this is a matter to be disputed in metaphysics.

XIII. As to the second ²⁷, he draws two corollaries. The first, that God cannot be defined: since every definition consists of a genus and differentiae, whereas God is not in a genus.

Second, that a demonstration cannot be made of it except through its effects: because the principle or middle term of a demonstration is the definition of the thing about which the demonstration is made. Since, then, there is no definition of God, it follows that there is no demonstration of him.

2. Concerning the second corollary and its argument, a doubt is raised. For if demonstration cannot be about God precisely because there is no definition of Him, it follows that there can be no demonstration about being, nor about substance, nor about any other most general genus. And consequently metaphysics, which treats of being and substance, and mathematics, which treats of quantity, will not be sciences. — The inference is evident. Because none of these has a definition composed of genus and difference, since none of them has any genus above itself.

To make this evident, we must consider that we can speak of demonstration a priori in two ways. In one way, of that whose middle term is truly and really the cause of the inherence of the passion in the subject about which the demonstration is made. In another way, of that whose middle term is not truly and really the cause of the passion, but is only a middle term according to reason, insofar as it states a certain reason prior by reason to that which is taken as the passion, and is the reason why such a passion is in the subject. The first demonstration requires that the middle term be a true definition composed of genus and difference: because the true cause of a determinate passion is the quiddity and essence of the thing under the genus, which is signified by the true definition; for the properties of a genus not subsisting in another genus are not really caused by the nature of that genus, since it does not belong to a genus to have esse except insofar as it is limited by the differences to the species. — The second demonstration, however, does not require a true definition as its middle term, but it suffices that it be some conception of the intellect prior by a certain essential order to the reason of the passion, and completely explicating the nature of the subject.

It is said, therefore, first, that of God there can in no way be a demonstration taken in the first mode, since in God nothing is truly caused. And this has been fittingly proved by the fact that God has no definition.

It is said secondly, that certainly there is no demonstration of being or of the most general genera in that way: for the same reason.

It is said thirdly that it does not follow that metaphysics and mathematics are not sciences. For although nothing about being and the most general genera can be demonstrated through the first kind of demonstration, something about them can nevertheless be demonstrated through the second kind of demonstration. For although these do not have a definition, they nevertheless have, as Saint Thomas says in V Metaph., lect. 4 ²⁸, a certain simple conception of the intellect, which can be called a ratio.

It is said fourth, that neither in the second way can there be a demonstration concerning God in a perfect manner, neither with respect to us nor in itself. For we cannot have any concept of the intellect that perfectly explicates the quiddity of God. And God's concept in itself is one alone: because all things that are in Him, when spoken absolutely, belong to His concept; and thus on the side of the thing it is not necessary to distinguish a concept pertaining to the quiddity of God from one pertaining to a passion, so that one concept would be demonstrated and another be the medium of demonstration. And therefore Saint Thomas says that concerning Him there can be no demonstration except through an effect.

XIV. As to the third ²⁹, he removes such a doubt. For someone might say that, although substance, which is a genus, does not belong to God with respect to that from which the name is imposed—namely, standing under accidents—it nevertheless belongs to God with respect to the thing signified: for God is a being through himself, which is the ratio of substance.

But he responds that being per se is not contained in the definition of substance, which is a genus. For from the fact that something is called “being,” it cannot be a genus, since being cannot be a genus. Nor from the fact that it is called “per se,” because this expresses a negation, namely, not being in another; and a negation cannot serve as the account of a genus, for then a genus would signify not what a thing is, but what it is not. But the account of substance is that it is a thing to which it belongs to be not in a subject. And since the name of a thing is imposed from its quiddity, just as the name “being” is from esse, there is understood in the account of substance that it has a quiddity to which it belongs to be not in another, as it were something distinct from its quiddity. Therefore substance, which is a genus, does not apply to God, since its account does not apply to him; for God does not have a quiddity distinct from esse. And it is denied that to be a being per se is the account of substance, as was assumed.

Concerning what Saint Thomas says, namely that in the definition of substance there is not "being per se," it should be known that certain Thomists understand these words as if he wished to say that being does not fall within the concept of substance, which is a genus. But this interpretation does not accord with the mind of Saint Thomas. For he does not say absolutely that being is not posited in the definition of substance, but that this whole, "being per se," is not posited in the definition of substance, that is, it is not the definition of substance, because from no part of that notion could substance have the character of a genus. But its definition, or notion, according to Avicenna ³⁰, is what I say: A thing to which is owed esse not in another. According to this, the character of a genus can befit it, since it expresses some special positive mode of being.