Commentaria in Summam contra Gentiles, Liber I

After St. Thomas has excluded from God composition of a quantitative kind, he now wishes to exclude the composition of supposit and nature ¹.

And he posits this conclusion: God is his own essence, that is, his quiddity or nature.

For the clarification of this, it must be known that the name God is taken in one way by the philosophers and in another by the theologians. For since the philosophers did not know the trinity of the divine Persons, but posited only one suppositum in the divine nature, therefore by the name of God they signify one having the divine nature and that one suppositum which, according to them, subsists in the divine nature: just as by the name of sun they signify that which has the nature of sun and subsists in the nature of sun. But among the theologians, who posit a trinity of divine Persons, by the name of God is signified one having the divine nature indistinctly, but not a determinate suppositum of that nature: just as by the name man is signified one having humanity indistinctly. And because Saint Thomas had not yet determined concerning the trinity of Persons, therefore, admitting the position of the philosophers, he shows that this suppositum of deity does not differ from deity itself. And he argues thus.

I. First ². If God were not His own essence, there would be in Him some composition. But the opposite of this has been shown above. Therefore, etc. — The consequence is proved in two ways. First, because from the opposite of the consequent the opposite of the antecedent is inferred. For if there is no composition in Him, then there is nothing in Him distinct from His essence. Therefore He is His own essence. — It is confirmed, secondly, because in composite things essence is signified in the manner of a part. Therefore it is a sign that where there is something besides the essence, there is composition; otherwise it would not be signified in the manner of a part.

2. But a doubt arises concerning this sign. For if, because the essence is signified in the manner of a part, it is argued that there is composition there, then there will be composition in God as well: for His essence is signified in the manner of a part; for there is the deity by which God is God, just as the humanity by which man is man.

To make this evident, it must be considered, from the teaching of St. Thomas Quodl. II, q. 2, a. 2, ad 1 ³, that since the supposit in beings is threefold—namely the uncreated, which is God; the created immaterial, which are the intelligences; and the created material, which are substances composed of matter and form—the supposit is related to nature in them in three ways. For the material created supposit includes three things in reality: namely, the essence; the individuating principles, which limit the essence so that it may be this one and distinct, such as this quantity, this figure, and so on; and the accidents, which contribute nothing to the individuation of the nature, such as whiteness, knowledge, and the like. — The immaterial supposit, however, includes only two things: namely, the essence; and certain things besides the essence that contribute nothing to the individuation of the nature, such as esse and certain other accidents belonging to the supposit. For in those beings there is no need to posit any individuating principle, since their very nature is of itself this one and individual. — The divine supposit, however, signifies nothing else in reality than the essence: since neither are there individuating principles there, because the deity is of itself this one and indivisible; nor are there other accidents extrinsic to the individuated nature, since nothing is accidental in God.

From this it follows that, insofar as the thing itself is concerned, the divine essence can in no way have the character of a part in a divine supposit: since by the formal account of a divine supposit nothing really distinct from its essence is imported on the side of the thing, nor is anything joined to it as an accident in reality. — In an immaterial created supposit, however, it has in some way the character of a part: insofar as the supposit includes in reality both the essence itself and the accidents existing in it. Yet it is not simply a part of the supposit: because those accidents, since they do not individuate the nature, are not of the intrinsic formal account of the supposit. — In a material supposit, however, it simply has the character of a part: because it is a formal part of its account. For a material supposit, in its formal account, intrinsically includes both the essence itself and the individuating principles: not indeed as constituting the substance of Socrates, since a substance is not constituted out of accidents; but as limiting the essence so that it may be this and individual, as is imported through the supposit.

From this it further follows that the mode of signifying by way of a part has some foundation in reality in created essence, whether material or immaterial, and does not depend only on the side of the signifying name, but also on the side of the thing signified. In the divine essence, however, it has no foundation in reality, nor does it depend on the side of the thing signified, but only on the side of the signifying name. For because in material creatures forms do not subsist but only composites do, therefore names imposed to signify simple forms retain a mode of signifying by way of a part, even though the thing signified in no way has the character of a part: as is the case with the name deity.

3. But a doubt arises here. For when one thing includes several things, one of which stands as receiver and the other as received, that which has the character of the receiver has the character of matter, while that which has the character of the received has the character of form: for it belongs to matter to receive, and to form to be received. But if the material supposit intrinsically includes essence, accidents, and individuating principles, then the essence itself is the receiver, while the accidents are what is received. Therefore the essence will stand as the material part, not as the formal part. The opposite of this has been said. — The minor is proved: because accidents are received in substance, but substance is not received in accidents.

To make this evident, it must be considered that we do not say that a supposit includes an essence and individuating accidents as though, once the essence had first been constituted in specific esse, accidents then accrued to it, individuating it and drawing it to suppositale esse, as the argument seems to suppose; rather, we imagine that matter is first disposed and limited by quantity and the other accidents that individuate it; then a form is united to matter so disposed according to its ultimate perfection; from these united there results an individuated essence. Hence the individuating accidents, since they are dispositions inhering on the side of matter, are reduced to the genus of material cause: and consequently the essence is compared to them formally.

To the argument, therefore, the minor is denied. — To the proof, the consequence is denied. For although these accidents are received in substance, they are not received in this substance which is the essence of the species as dispositions of matter; rather, since the material form gives corporeal esse and this esse, say of a horse, they are understood to be received in matter insofar as it is actualized by the form according to corporeal esse only, but still in potency with respect to the esse of a horse, to which esse it is disposed by accidents of this kind. For these accidents are pre-understood in matter, by way of generation, up to the last degree, which substantial form gives. But there will be a fuller discussion of these below, chapter LXXI ⁴.

4. To the principal argument, therefore, ⁵ it is said that from the fact that in composite things the essence is signified in the manner of a part—a mode of signifying grounded on the side of the thing signified and having its foundation in the thing itself—Saint Thomas argues that there is composition in the thing. But he does not argue this from a mode of signifying that has no foundation in the thing and holds only on the side of the name signifying, as happens in the mode of signifying the divine essence. Therefore it does not follow that there is any composition in God.

II. Second. In God there are no accidents, as was shown above ⁶, where it was shown that there is nothing in God beyond his nature, and no composition in him, and that there is no potency in him ⁷. Therefore he is his own essence. — The consequence is proved: because if he were not his own essence, there would be something in him beyond the quiddity, which is signified by the definition. But only accidents are things that do not fall within a definition.

It must be noted that Saint Thomas here speaks of the definition of essence and specific nature insofar as he expounds only the essential principles: for of this definition it is true that whatever does not fall within it is an accident, and that nothing foreign to the essence falls within it. But we said in the preceding argument ⁸ that individuating accidents fall into the definition of the individual and subsistent thing, not as essential principles, but as certain determinations and limitations of the essence. Therefore it follows that, where a thing is not its own quiddity, there is something in it besides the essence which is not part of the essence. And consequently there is in it some accident: for what does not fall within the definition as part of the essence must necessarily be an accident.

III. Third. Forms that are predicated neither universally nor particularly of subsisting things do not subsist individuated in themselves. But the divine essence exists singularly of itself, individual in itself. Therefore it is predicated of a thing. Therefore this is true: God is deity. For the discussion here concerns such a predication, in which it is said, This is this.

The antecedent is shown by induction. Whiteness, for instance, because it does not subsist but is individuated through a subject, is therefore not predicated of Socrates or a man, so as to say, Socrates or a man is whiteness. Similarly, particular forms, because they are individuated in their own matters, are not predicated of the thing: for we do not say that this fire is its form. The quiddities of things themselves are also individuated according to designated matter, of this or that individual, even though they include form and matter in common: therefore we do not say that Socrates or man is humanity. Therefore a form that is not predicated of the thing does not subsist per se — namely, as it were, individual of itself; which I say on account of the intellective soul, for it indeed subsists per se, but it is not individual of itself.

It should be noted here that in every predication the unity of the predicate with the subject is conveyed, but in one way when the concrete is predicated, and in another way when the abstract is predicated. For when the concrete is predicated, insofar as it follows from the mode of the concrete, unity is signified simply between the thing having the form and the form, but as regards the form, a qualified unity. When, however, the abstract is predicated, unity is signified simply between the subject and the form of the predicate. For when I say Socrates is white, it is signified that Socrates is one simply with the thing having whiteness; but with the whiteness there is a unity per accidens, which is between the subject and an accident. But when it is said, Socrates is whiteness, unity is signified simply between Socrates and whiteness. On account of this, where the supposit and the nature conveyed by the abstract name are not simply the same, essence is not predicated of the supposit. Where, however, they are simply the same, the predication of one of the other is true.

IV. Concerning that proposition, the essences of genera and species are individuated according to the designated matter of this or that individual, it must be known that certain Thomists by designated matter understand that matter itself which is capable of this quantity and not of that; but they say that this capacity is not something really distinct from the matter itself ⁹. Hence designated matter adds nothing above matter that would be really distinct from it, but only a capacity for this quantity, which capacity is distinguished from it by reason alone. For these men imagine that the particular agent appropriates matter to this particular form: so that in the first instant of Socrates' generation there is first, in the order of nature, brought about the particular composite, and then all the accidents follow in natural order; but in that prior order of nature in which the particular composite first and per se terminates the generation, the matter which is an intrinsic part of Socrates is so appropriated to Socrates himself that it is not capable of any other quantity than that which Socrates determines for himself. And matter thus appropriated is called designated matter.

But, although this opinion belongs to a most learned man, it does not seem to me to accord with the mind of St. Thomas. For, if designated matter is nothing other than matter appropriated to Socrates and thus capable of the quantity of Socrates and of no one else, I ask: in that prior state according to nature in which it is said to be appropriated to him, is there some form in the matter by which it is appropriated to this soul of Socrates, or none? If there is some form, whether substantial or accidental, then appropriated and designated matter does not signify prime matter alone, but matter together with a form by which it is said to be appropriated and designated. If there is none: against this — no potency receives limitation and appropriation except through some act which it receives, as is held from St. Thomas, First Part, q. VII, a. 1. But prime matter is potency simply. Therefore it does not receive determination and appropriation except through some form: for it is the role of act and forms to determine and limit. If therefore designated matter must exist so that through it the form may be individuated by such designation, it is necessary that there be in it some act really distinct from the matter. Therefore designated matter does not signify prime matter itself to the exclusion of everything really distinct from it, but matter together with some limiting form.

For which reason another opinion seems to me more in accord with the mind of St. Thomas, which holds that by designated matter is to be understood matter under quantity: so that both matter and quantity concur in individuation. Matter indeed, insofar as the individual is incommunicable through the exclusion of that communication whereby the universal is communicated to a particular: for because matter is the first subject, received into no inferior subject, therefore nature received in matter, as such, cannot be communicated to any inferior. Quantity, however, concurs insofar as the individual is distinguished from every other individual of the same species by quantitative and material distinction. Hence, just as two things belong to the individual, namely incommunicability and distinction, so designated matter, which is the principle of individuation, includes two things, namely matter itself, which is incommunicable, and quantity, to which material distinction pertains first; so that neither does matter alone individuate nor quantity alone, but it is matter signed and limited by quantity that individuates, giving incommunicability by reason of matter, and distinguishing numerically by reason of its determination through quantity.

That this is the mind of St. Thomas appears from IIIa P., q. LXXVII, a. 2; likewise from the Fourth Book, d. XII, q. I, a. 1 ¹⁰, where he posits that, since two things belong to the notion of the individual, namely incommunicability and material distinction from others, the principle of one of these is matter, while that of the other is quantity; and thus the total principle of individuation is designated matter, that is, matter under quantity (which is said to be its sign, because through it it becomes sensible and determined to here and now), as is stated in the treatise on the Principle of Individuation ¹¹.

V. Against this exposition the arguments of the first opinion do not stand in the way. For it argues as follows. First. The principle of the individual's distinction from the species is the same as that of its distinction from another individual of the same species: just as it is universally true that, whenever something common is divided into several subjective parts, the inferiors differ from one another and from the superior by the same principle, as is evident in the case of the species of any genus. But matter not as quantified, but as thus appropriated, as we said, is the intrinsic principle of distinction of the individual from the species, as St. Thomas holds in the treatise on the Principle of Individuation. Therefore it is not quantified matter, but matter thus appropriated, that is the principle of the distinction of one from another.

Second. In this way each thing has unity in the manner in which it has esse, as is said in the Prima, q. 76, a. 2, ad 2. But Socrates is not Socrates formally by quantity, but by his substance. Therefore he is neither one in number nor distinct in number formally by quantity. Therefore quantity is not the principle of individuation with respect to distinction.

2. But the response to the first is given in two ways. First, that the major premise is false with respect to material and individual distinction: whatever may be said of formal and specific distinction. For by this matter an individual is distinguished from the species, because from it the individual has that it is incommunicable, while the nature is communicable; but it is distinguished materially from another individual by quantity.

Second, that the minor is also false. For the individual is not distinguished from the species by matter alone, but by matter designated under quantity: for by this the individual has what makes it determined to this here and now, in which it is distinguished from the species, which abstracts from this here and now. Nor does Saint Thomas say the opposite of this in that treatise; rather, what is said here concerning his mind will be evident there to those who consider it diligently.

3. To the second it is said first that, if this argument were conclusive, it would prove through transcendental unity itself that it is identical with numerical unity, as Avicenna held ¹²; which is rejected by Averroes and St. Thomas, IV Metaphysics, comm. 3 ¹³. For the argument would run thus: Each thing has numerical unity in the same way in which it has esse. But Socrates is a being by his entitative act. Therefore he is one in number by his entitative act. Therefore numerical unity is the same as his essence. And thus numerical unity and transcendental unity will be the same: for transcendental unity, according to St. Thomas ¹⁴, signifies the essence of a thing together with its individuation.

It is said second, that a twofold unity belongs to Socrates: one, namely transcendent; and another of the genus of quantity, according to which he is counted together with other quanta, and by which he is this thing, marked out and pointed to. If therefore we speak of the esse of a thing absolutely, the proposition of St. Thomas has truth with respect to the unity corresponding to it absolutely, which is transcendent unity: for thus it is true that each thing, in whatever way it has esse, also has transcendent unity; because just as something concurs toward the esse of a thing, so also toward such unity of it. And in this sense St. Thomas spoke in the passage cited: for there he speaks of the intellectual soul, which is admittedly one not quantitatively, if it is taken precisely as such, but only transcendentally, since quantitative unity belongs only to material things, as St. Thomas holds in De potentia q. IX, a. 7; hence he holds that, because the soul does not depend on the body with respect to its esse—although it has esse in the body, as will be explained in the Second Part of this work ¹⁵—therefore neither does it depend on the body with respect to its unity. — But if we speak of quantitative esse, the said proposition has truth with respect to the unity proportionate to it, which is unity of the genus of quantity: although St. Thomas did not put it forward there in this sense. For in whatever way each thing has quantitative esse, in that same way it has unity of the genus of quantity. And because nothing has quantitative esse except through quantity formally, therefore each thing through quantity is formally one by quantitative unity. It is of this unity that we speak when we say that nature is formally individuated and has material distinction from another through quantity. For St. Thomas says that quantity concurs toward individuation because through it the individual is this thing, marked out and pointed to, materially and numerically distinct from all others of the same species ¹⁶.

To the argument, therefore, it is said that if the major is understood, as Saint Thomas takes it, concerning esse absolutely and concerning transcendent unity, the whole argument is conceded: for we do not say that quantity is the formal principle by which Socrates is one transcendentally, although it is the cause without which he is not distinct from Plato transcendentally in the same species; for the humanity of Socrates is not this humanity except through this matter, and matter is not this matter distinct from that matter unless it is under this quantity. — But if the major is taken as we said, and the argument proceeds to numerical unity, the argument is denied. For, as is evident, the fallacy of equivocation is committed: for in the premises transcendent unity is taken, and in the conclusion unity of the genus of quantity. — But if that major is taken in the second sense, the argument is likewise denied. For the minor is not rightly subsumed. For it ought to be, But Socrates is not formally quantified by quantity. Which is clearly false.

Although Scotus, in II Sent., d. III, q. VI, disagrees with Saint Thomas on the principle of individuation, yet since this question has been most fully discussed by others ¹⁷, let these remarks suffice.

VI. Only one difficulty arises. For according to the doctrine of Saint Thomas, the substantial form arrives in the first instant of its esse upon naked matter; and prior in nature, form actualizes matter before accidents inhere in it. Therefore, in that prior instant in which form is united to matter, the individual is constituted, and yet there is no quantity there, but matter alone. Therefore, matter alone is the principle of individuation, and quantity does not concur with it.

It is said in reply to this, first, that there is no instant in reality at which a material form is united to matter without quantity: because this form is united only to this matter, distinct from other matter by another part; but matter is not this and distinct from other matter except through quantity, as Saint Thomas says, on Boethius De Trinitate, q. IV, a. 2 ¹⁸, and according to the mind of Aristotle, Physics I ¹⁹. Therefore there is never an individual in nature that is not incommunicable and distinct, determined to this here and now, and thus has both matter and quantity.

It is said secondly that, although this is so in reality, the intellect is naturally inclined to understand separately things that exist together; and all accidents presuppose, by nature, that form be in matter in the genus of formal cause, although in the genus of material and dispositional cause it is the reverse with respect to certain things in relation to some degree of form, as will be explained in Book Two of this work ²⁰. It might seem to someone that we first understand form to be in matter and a composite to be constituted, before accidents inhere in it; and then in that prior consideration of ours the individual would be understood as such with respect to the principal condition of an individual, namely incommunicability, but not with respect to distinction and designation as this here and now. But perhaps even this is not true. For form cannot be understood to be in matter and to constitute this supposit unless quantity is first understood in the matter, by which it is made this and distinct from another part of matter: for form does not become this except because it is received in this matter; but matter is not this except by some act limiting and distinguishing it. If, therefore, the argument takes as its premise that at some instant outside the intellect form is in matter while quantity is not also there, that assumption is false. But if the talk concerns the prior instant according to our consideration, then it is false that in that prior moment the individual is understood as constituted, at least with respect to numerical distinction from another individual.

VII. Concerning that proposition, "The quiddity of genus or species includes form and matter in common," a doubt is raised: for it seems to conflict with what we said just now. For if common matter is granted, how does the individual derive its incommunicability from matter as from something incommunicable?

To make this evident, it must be considered that matter can be regarded in two ways: in one way, in itself absolutely, that is, according to its entity, by which it is distinguished from form; in another way, according to the relation it has to the form from which its intelligibility is taken. In the first way, it is not common, but one and indivisible—not indeed in the manner of a point, but by the negation of every distinctive act; and it is the ultimate subject into which all material things are resolved. And thus it is incommunicable by that communication by which a superior is communicated to its inferior. — In the second way, however, it can be common according to its intelligibility, namely insofar as it is conceived together with a relation to form considered in general; but it is particular insofar as it has a relation to a particular form; so that the commonness of its intelligibility belongs to it only from the form to which it has a relation.

It is said, therefore, in answer to the doubt that there is a common matter according to reason, insofar as it is compared to a common form, for instance of bone or of flesh. And such matter is posited in the definition of material genera and species as a part of the essence, although the Commentator, VII Metaphysics, comm. 21 and 34, seems to wish that it not be posited in the definition as a part of the essence, but as bearing the essence. This, however, does not contradict what we said, namely, that it is incommunicable: for we were speaking there of matter considered in itself and according to its own entity, which has the character of what is common to no degree, but of one thing and indivisible.

VIII. But a doubt still remains. For the community does not seem to be greater, according to what is said here, in the genus or species than in matter. For the entity of the genus and of the difference, according to the esse it has outside the intellect in one individual, is incommunicable and indivisible; but in the intellect it is common, contractible and divisible through differences, whether formal or material. Therefore, if matter in the intellect is common according to the aspect of commonness, divisible by quantity, while outside the intellect it is indivisible in one singular by the indivision of the superior in the inferiors: it is no less common to this and that matter than the genus and species are to their inferiors.

It is answered first, that the community of the ratio of matter is one thing, and the community of the ratio of genus and species another. For to the common ratio of genus and species there corresponds in reality a common nature: not indeed one that is common in any single singular, but one that by its own nature is apt to be separated by the intellect from its limiting principles and to be conceived universally. But to the common ratio and concept of matter there does not correspond one common nature of matter existing in many matters and abstractable by the intellect from them in itself; rather, it belongs to matter only from without that it be conceived universally, namely from the fact that it is conceived in relation to a common form.

It is said second, that matter is not only indivisible according to the esse it has in one individual—which also belongs to genera and species—but is also indivisible according to its own nature and entity, and is one in number, as is said in I Phys. ²¹, nor can it be divided into more inferior things. For although it is divided into several parts by quantity, this is nevertheless not a division of a superior into inferiors, but rather of some quantitative and extended whole into its parts: for by quantity it has both division and extension.

IX. Fourthly ²². In no way can anything be the cause of God. Therefore God is His own essence. — The consequence is proved: because where a thing is not its own essence, that essence stands to the thing in some way as a cause.

Note that essence, when it is distinguished from the supposit, has with respect to it the character of a formal cause, from which it has that it is such: as from humanity Socrates has that he is a man. Nevertheless, because it is not distinguished from the supposit as an entity entirely distinct from the entity of the supposit, but rather because the supposit says this very essence itself and adds something above it; whereas what is a cause simply and absolutely is entirely distinct from its effect: therefore he did not say that it is simply a cause, but that it stands in some way to the supposit as a cause.

X. Finally. In God there is no potentiality. Therefore He is His own essence. — The consequence is proved. For that which is not its own essence is related to it, in respect of something of itself, as potency to act.

But it seems rather the opposite: namely, that in such a supposit the essence stands as matter, not as act. For those things that the supposit adds above the essence limit and contract and determine the essence itself. But it belongs to act to determine, and to matter to be determined.

It is said that matter is limited by form, and form by matter: for they are causes of one another, as is said in Physics II. ²³ Hence it belongs to form to limit and determine potency, but to matter to determine and limit act. Therefore designated matter, which is the principle of individuation, and the very accidents which the individual has over and above its essence, since they belong on the side of matter as designating it, do not limit the essence in the way act limits and contracts potency, but in the way matter limits and contracts the amplitude of form: for the essence is this one because it is received in such matter. It does not therefore follow that it has the character of matter and potency, but of act and form.