Commentaria in Summam contra Gentiles, Liber I

From the preceding chapter Saint Thomas draws this conclusion: God is not matter ¹. Concerning this he does two things: first he proves the conclusion; second, from what has been determined he excludes a certain error ².

I. The first argument for the conclusion is this. In God there is no potency toward substantial esse. Therefore God is not matter. — The consequence is proved: because prime matter is that which is in potency.

Note that matter is in potency differently from the thing made out of matter. For matter is not in potency in such a way that it could be produced and subsist in act, as fire is: since it is ungenerable and incorruptible, as is said in I Physics, chapter LXXIV. ^[] Rather, it is potency essentially: because it is itself potency, and it is the receptive subject of act. This mode of speaking St. Thomas intimates when he says, "Matter, that which is, is in potency": that is, according to its whole essence it is a receptive potency of act; so that the essentiality of the potency is signified when he says "that which is," and the order to act when he says "is in potency." — But the thing made, before it exists, is in potency because it can exist in act through the action of an agent, and there is some potency in matter from which it can be educed.

Second. God is the first efficient cause. Therefore He is not matter. — The consequence holds: because agent and matter do not coincide in the same thing, according to the Philosopher, Physics II. ³ and Metaphysics V. ⁴

Third. If matter existed, all things would be the result of chance.

Fourth. God is immobile. Therefore he is not matter. — The consequence is evident, because matter does not become the cause of anything in act except insofar as it is altered and changed.

It must be noted that it is one thing for matter to be a part of something, and another for matter to become the cause of something in act. For matter to be a part of something is for it to constitute partially the essence of the composite thing. This can occur without alteration or change of the matter, as we see in heavenly bodies. But for matter to become the cause of something in act is for it, previously existing without causing that thing, afterwards to cause it actually within its own genus. Now this cannot happen except through alteration and change, by which it is both stripped of its present form and clothed with another; for matter which exists under the form of air cannot become the actual cause of the form of fire except through an alteration of the form from which it will be stripped. Therefore, since we posit God as the first cause, and something to be newly caused by him, if there were matter, it would be necessary that through some change it become the actual cause of that of which it was only the cause in potency.

II. As to the second ⁵, he refutes the foolish position of David of Dinant, who thought that God was prime matter, deceived by this argument: if God and matter were not the same, they would differ by certain differences; and thus they would not be simple, because a difference introduces some composition into that which differs. But Saint Thomas answers that here he was ignorant of what lies between the differing and the diverse. For "differing" is indeed said with respect to something, because something differs by some respect, as is clear in Metaphysics X, text 12; but "diverse" is said absolutely, from the fact that it is not the same. For a difference must be sought between things that agree in something: therefore they must differ by differences under that common element. But things that are diverse have nothing in common in which they agree: therefore one need not seek by what they differ, but they can be diverse of themselves. Thus opposed differences are distinguished: for they are diverse of themselves, and not by other differences, since they do not participate in a genus as part of their essence. So too God and prime matter are diverse of themselves, as agreeing in nothing.

III. For the declaration of what is said here, one must recall what is found in Metaphysics V and X ⁶ namely, that diversity is opposed to identity, and universally imports non-identity. Hence, however things may not be the same, they can be called diverse. A difference, however, if we wish to use the word properly, is said of that which agrees with another in something, but is distinguished from it by certain differences of that common thing: as man, who agrees with horse in the genus animal, differs from it by rationality. Hence every difference is a diversity, because it is in some way non-identity; but not every diversity is a difference, because even those things which agree in nothing can be called diverse, yet not different. Nevertheless we sometimes use one word indistinctly for the other. Whence it happens that whatever are diverse in any way, we say they differ because they are not the same: not because they are distinguished under some common thing by certain differences.

It must also be considered, in light of what he says—that the differences do not share in the genus as a part of their essence—that the genus can be considered in two ways: one way materially; the other formally. If it is considered materially, that is, with respect to its entity alone, then it is not a part either of the species or of the difference, but it signifies the whole entity both of the species and of the difference. But if it is considered formally, namely insofar as it corresponds as a foundation to a concept common to all its species, then it signifies a part of the essence of the species, but not of the difference, if we take the essence of the thing formally, namely insofar as the nature corresponds to the definitive concept of the intellect. For in the essential definition of the species the genus is included as a part of the definition: therefore it is said to be a part of the essence of the species. But the genus is not posited in the definition of the difference as a part of it, nor is the genus predicated of it formally, as is said in Metaphysics III ⁷: otherwise there would be idle repetition in definitions. Therefore the genus does not signify a part of the essence of the difference, although it is materially one with it. And for this reason they are said to be primarily diverse, because they agree in no common objective concept.

IV. But three doubts arise. The first is this. For something is not called relative because it is such by means of something, but because it is referred to another as to a correlative. For white is not a relative, even though it is white by whiteness. Therefore, although the different differs by means of something, it is not on that account relative. St. Thomas seems to hold the opposite here, when he says that the different is said in relation to something.

The second reason is that the diverse does not seem to be distinguished from the different in the way proposed here. For just as a different thing is different by some difference, so too a diverse thing is diverse by some diversity. And thus, by the same account on which one is said in relation to something, so also is the other.

The third is this. Matter and God agree in being. Therefore they are different: because, as the Philosopher says, Metaphysics V, text 15 ⁸, whatever things are diverse are different, being in some way the same either in number or species or genus or proportion. And concerning "one by proportion," Saint Thomas gives there an example of quantity and quality in a being. Therefore it is false what Saint Thomas says, that they have no agreement in anything and are not different.

V. For the clarification of these points, it must be considered that in that which is said relatively, besides the term to which it is referred, there must be something by which it is referred to the term, in some way distinct from the term itself. For in that which is like, there must be a relation by which it is assimilated to another, and some quality which is the foundation of the likeness: for the like is like by some likeness, and according to some quality. But that which is said negatively does not need anything by which it is said negatively; rather, of itself it can be denied of another. If, therefore, "differing" is relative, there must be in it something by which it differs from the term. But "diverse," because it is absolute—that is, not importing of itself a respect to another—does not need anything by which it is diverse; rather, by its whole self it can be denied. On account of this, wishing to assign the mode in which they are distinguished, Saint Thomas interposed, on the authority of Aristotle, that one is relative and the other absolute: from which it follows that in the one there is something by which it is said such, but in the other not. Therefore "to something," or relative, is said with respect to two things: namely, to one as to the term only and correlate, but to the other as to the reason of referring; for the father is said with respect to the son as to the term, but with respect to paternity as to the reason of referring: for the father is father formally by paternity, and fundamentally by the power or act of generating. Therefore "differing" is relative, because it is said with respect to that by which it differs as to the reason of referring, not as to the term: but "diverse" is not said with respect to something as to the reason of referring.

VI. To the first ⁹ therefore it can first be answered that, although something is not relative because by something it is such in whatever way, nevertheless something is said to be toward another because by something it is such as by a reason of referring to another. This does not belong to white. For although white is white by whiteness, yet the name "white" does not import whiteness as a reason of referring to another.

It can be answered secondly that the relative and the ad aliquid can be taken in two ways, just as the absolute can. For something is said to be absolute either because it is absolved from a term, as quantity is, for quantity, as such, is not said to be toward another as toward a term; or because it is absolved from a subject or from a form or in any other way from another, as substance is absolute with respect to a subject, and an accident with respect to the form by which it is such, for an accident is not an accident by some form added to it, but by itself. Similarly, therefore, something is said to be ad aliquid either only as toward a term, or as toward a subject or a form, or in any other way than only as toward a term. Therefore, when difference is said to be ad aliquid, that is, relative, as is stated in I Sent. ¹⁰, the ad aliquid is taken not as toward a term, which is properly what is ad aliquid, but as toward a form, which in an extended sense can be called ad aliquid: for difference imports some form by which it is different. But diversity does not import a form by which it is diverse, but can be diverse of itself. Hence it is said to be absolute with respect to form. — In this way it is granted that white is said to be ad aliquid as toward a form, for everything white is white by whiteness; although it is not ad aliquid as toward an extrinsic term.

We can draw this distinction from St. Thomas, Metaphysics V, the chapter on "to something" ¹¹, where he says that sight can rightly be called "of the one seeing," not insofar as it is sight, for in that respect it is called "visible," but insofar as it is an accident or power of the one seeing: for a relation looks to something outside, and it looks to the subject only insofar as it is an accident. Therefore, just as sight has a relation both to the visible and to the one seeing, though, insofar as it is properly a relative, it is said to be "to the visible," while insofar as it is an accident or power it is said to be "to the subject," and in this way too it can be called relative in a broad sense, because it imports a relation to another, namely to the subject; so the different imports a relation to that from which it differs as to an extrinsic term, and as such it is properly a relative; it also imports a relation to the difference as to the form by which it is different; and thus it can be called "to something" in a broad sense, insofar as anything whatever that imports a relation to another can be called "to something."

This answer seems more in keeping with the mind of the holy Doctor. For in the Prima, q. III, a. 8, ad 3, he says: Hence, according to the Philosopher, X Metaph., the diverse is said absolutely, but everything differing differs by something. From this he gives us to understand that he takes "absolute" as equivalent to "the same," that is, not importing a form distinct from itself by which it may be such; and likewise "relative" (ad aliquid) as importing a form by which it may be such, somehow distinct from itself. Also in the First Book of the Sentences, d. VIII, q. I, a. 2, ad 3, explaining the mind of the Philosopher on how the diverse is absolute and the different relative, he assigns as the reason that everything differing differs by something, but not everything diverse is diverse by something.

VII. To the second, it is said at ¹² that "diverse" and "diversity" are said negatively, just as "not the same" and "non-identity." Hence the diverse is not diverse by some diversity as by a form, but as by a negation of form.

It must also be noted that, although "diverse" seems to be said relatively and with respect to something—for what is diverse from something is diverse—nevertheless that preposition "from" does not import a term of relation but of negation: for it imports that with which something is not identical; just as, when it is said that Socrates not existing is distinguished from Plato not existing, no order of one to the other is imported, but a negation of one from the other. Hence the diverse is not relative but absolute.

VIII. To the third ¹³ it is said that difference, if taken properly, is said of those things that are distinguished by genus or species, as is said in Metaphysics X, text 12 ¹⁴ Hence it does not suffice for a difference properly so called that certain things agree in one common analogical and proportional term, but it is required that each of them be in some genus or species. Hence the Philosopher says there, in Metaphysics X, that that by which certain things differ must be something the same (in things that do not differ in this way ¹⁵): and this is genus or species.

But what St. Thomas says, and Aristotle as well—that even things which are one by proportion are different—is to be understood on the supposition that each of them is in a genus. And when he gives the example of quantity and quality, which are united in being, he does not take these for the most general genera, but for species of genera, say, for line and whiteness: for these differ in genus and agree in nothing except in being said of them proportionally.

To the argument, therefore, it is said that, although God and matter agree in being, taken proportionally of them, they do not nevertheless agree as things of different genera or different species, as St. Thomas understands, who refers himself to Aristotle, Metaphysics X. — Similarly, it must be said concerning opposed differences. For although they agree in being, they are nevertheless not in any genus or species that would be predicated of them formally. Therefore they are distinguished by themselves, and not by other differences.