Commentaria in Primam Partem Summae Theologiae

A famous title. – In the body, a single conclusion, responsive to the question in the affirmative: In God there are only four real relations, namely paternity, filiation, spiration, and procession. – It is proved thus. In God there are real relations, and not consequent upon quantity, nor upon action toward what is outside: therefore they are consequent upon actions within: therefore in Him there are only relations consequent upon two processions within: therefore there are only four real relations: therefore these are the ones, paternity, filiation, spiration, and procession.

The antecedent, as regards quantity, is proved: because in it there is no quantity, as is clear from Augustine. As regards action ad extra, it is proved from what was said above in question XIII. – The first consequent, however, is proved from Book V of the Metaphysics: namely, because every relation is founded upon quantity, or upon action and passion. – The second, however, is proved from what has been said: namely, because according to immanent actions there are only two processions, one according to intellect, and the other according to will; the former of the word, the latter of love. – The third, however: because according to each procession there must be two opposite relations, that of the one proceeding and that of the one from whom it proceeds. – The fourth finally is proved, as regards the names of the first two relations, thus. The procession of the word is called generation, according to the proper notion of the nativity of living things: and the relation of the principle of this nativity is called paternity, while that of the one born is called filiation: therefore. As for the two remaining ones, it is made clear thus. The procession of love lacks a proper name: therefore also the relations according to it. And again, it is called procession or spiration: therefore fittingly the relation of the principle here is called spiration; while the relation of the one spirated is called, by borrowed usage of the name, procession. And so the whole is clear.

II. Concerning that proposition from V Metaphysics, note again¹, from the Questions On the Power of God, q. VII, art. 9, that it is understood according to mode, not according to the thing: that is, every real relation is founded upon quantity etc., that is, upon a thing which is quantity, or upon another thing as it takes on the character of quantity: hence unity in substance makes identity, and unity in quality makes likeness. For unity pertains to quantity modally.

But then a twofold doubt arises here. First, how much weight the argument from the letter carries, proceeding from the fact that in God there is no quantity according to reality, as is clear from the authority of Augustine cited above. – Second, because the authority seems to be brought in falsely from V Metaphysics: since there a third mode of relatives is posited, as St. Thomas also explains there, namely that of measure and measurable not quantitatively.

III. To the first of these it is said that, because according to the truth the Author holds that no real relation in God follows upon quantity, both as to the thing itself and as to its mode; and because he promises to treat below, in his response to the fourth, of such relations as follow upon quantity as to their mode, namely equality and likeness; therefore here he passed over the matter summarily, content with an argument concerning quantity as to the thing itself. – And if you press further, "Therefore from this article what was intended is not sufficiently concluded," it is answered that it was sufficient for the present place, since by this place those relations are deferred to be treated below; although not sufficient absolutely, if all things were to be examined here. On account of which, lest this limited treatise become an occasion of error to anyone, he protests in his response to the fourth that he will complete this matter below in its proper place, where the relations common to the divine Persons will be discussed: for thus the order as instituted required.

To the second doubt it is said that, since the discussion here concerns real relations between things of the same order, indeed of the same nature, or at least mutual ones; but relatives of the third mode, as is clear in the same place², differ from the others in that they are not mutual; therefore no falsity was committed in the citation. For that universal is true concerning mutual real relations, of which the discussion is had.