Commentaria in Primam Partem Summae Theologiae

The title is clear. – In the body there is a single conclusion, having three parts: the Father is in the Son, and conversely, according to essence and relation and origin.

As to the first part, it is proved thus. The essence of the Father is in the Son: therefore the Father is in the Son. – The antecedent is made manifest: because the Father communicates his essence to the Son without any transmutation. – But the consequence is proved: because the Father is his essence. – And likewise, conversely, the essence of the Son is in the Father: therefore the Son is in the Father, because the Son is his essence. – And this is confirmed by the authority of Hilary.

II. Concerning this part, note two things. The first is that the Father's being in the Son by reason of the essence can be understood in two ways. In one way, that the essence itself considered in itself is the reason of being (esse) in the Son; just as we say that the Father understands by reason of the essence. And this sense is foreign to the mind of the Author: for then it would follow most fittingly that therefore the Son is in the Son; just as it follows that therefore the Son understands. In another way, that the essence, as one in many, is the reason why one being is in another; just as we also say that the essence, as in the principle, is the reason of generating. And thus it is verified in the case at hand. For to be in another, since it requires two things, conjunction and distinction of extremes, occurs in two ways: either according to reason, with respect to distinction, as deity in God, and universally form in the supposit from which it is not really distinguished; or according to reality. In the case at hand it is understood according to reality, so that there concur toward the mutual being (esse) of the divine persons both real otherness and real conjunction: for the Father is in the Son as consubstantial in another consubstantial, by reason of the one essence in both.

Know secondly from this that esse in a person, as we are now speaking, is among the mixed notional notions, just like the power of generating: for it contains within itself the distinction of persons and the unity of essence. And therefore, just as in other things of this kind, which stand between the essential and the notional, an argument does not hold when applied to what is purely essential, so neither does it here. Hence, just as the essence does not generate, and yet in the Father is the reason for generating; so too it is not in any person in the way one person is in another, and yet in several persons it is the reason for their being (esse) in one another.

And from these it is clear, first, the efficacy of the argument from the letter, which proceeds not from the identity of the Father or of the Son with the essence, as some seem to have understood; but from the unity of the essence of both. And this is most fittingly intimated in the very names of the Father and of the Son and of the essence. – The solution to the arguments brought forward is clear, secondly, in distinction XIX of the First Part¹, at Capreolus. For both conditions joined together render the procession valid.

III. One doubt, however, remains: whether this argument holds from the unity of the essence of both, such that it would be equivalent to have said, the essence of the Father is in the Son, therefore etc., and, the essence of the Father is the Son, therefore etc.; that is, whether that mode of "in," as it lies in the text, is required for the force of the inference, namely, the essence of the Father is in the Son, therefore etc. – And the reason for the doubt is that the word "in" signifies only a relation of reason; but the Father is in the Son according to the thing itself. – And again, the essence is in the Son in a different way than the Father is in the Son: because the former is there as form in a supposit, whereas the latter is there as a substantial supposit in another supposit.

IV. To this it is said that, since the mode of signifying alone pertains to the truth of propositions, which sometimes varies their truth, therefore, although this process, as regards the thing, is grounded upon the unity of essence in the many (for this makes the persons consubstantial, and posits one substantially in another as regards the thing); nevertheless, as regards showing what is properly verified by this utterance, the Father is in the Son, and conversely, it is also grounded upon the ly in. For from the fact that the one essence of the many fittingly admits the ly in with respect to each of the singular persons, it follows most excellently: Therefore each person, by reason of that essence, can also be said to be in another.

Nor does the diversity of mode stand in the way: on the contrary, of necessity the mode of reason must be different from that of being, as is clear by induction. – Nor does it hinder that it signifies a relation of reason: since a relation of reason is also meant when it is said, the Father is in the Son, just as when it is said, equal to the Son; for there is no real relation in God besides those four relations of origin. Hence, just as equality and likeness of the persons are distinguished with respect to foundation and extremes, etc.²; so must mutual indwelling be spoken of proportionally: for it includes the unity of essence and the distinction of persons, just as those do, as is clear from what has been said³.

V. As to the second part, however,⁴ it is proved. One correlative is in the other according to the intellect: therefore one divine person is in the other according to relation.

VI. Against this argument Aureol and Durandus object, as reported by Capreolus in the place cited above⁵. First, because one relative is not in another, but toward another, and is distinguished from and opposed to it. – Second, because in that case the Holy Spirit would not be in the Father and the Son, since He is not referred to them: but in the spirator, to whom He is referred.

VII. But that these and similar things offer no obstacle is easily apparent, and the difference lies only in words. For the Author does not will that the Father be in the Son according to the thing, with respect to relation (since it is clear that the Father, as such, is toward the Son, not in the Son): but according to understanding, or the definitive account: for by most frequent usage we say that one correlative is in the account of the other, as Porphyry says in Praedicabilibus⁶ And since in the text it is expressly placed ly according to understanding, it is a wonder how these men argue against this.

Again, since it is sufficient for each mode to have what is proper to it beneath its formal account, there is no incongruity in granting that the Holy Spirit, with respect to relation, is not in the Father and the Son except as they are spirating him. For whatever is had from all the modes together need not be required from any single mode; this is what the objector dreams was the Author's intention. Hence, if from this one were to infer, therefore the Holy Spirit is not in the Father and the Son, or, therefore he is not in the Father and the Son except as in those spirating, that would be a sophism from a respect to something absolute. For he is in them thus; and he is in them by reason of essence, as consubstantial, as was said in the first mode⁷; and also according to origin, as will be said⁸. The argument therefore does not hold: the Holy Spirit, with respect to relation, is not in the Father and the Son except thus; therefore the Holy Spirit is not in them except thus: for the term with respect to relation functions as a respect.

VIII. As to the third part,⁹ it is proved. The Word does not proceed outside the one speaking, and what is said by the Word is contained in the Word: therefore one divine person is in another according to origin.

IX. Against this argument Aureol objects, above¹⁰, in two ways. First, because the mode of being in another as in a principle is more imperfect, as the Commentator holds, IV Physics, comment. 23; and it is not reciprocal. But the mode in which one divine person is in another is most perfect, and reciprocal. Therefore. — Second, because according to this argument the Father would be in the Word just as the whole world is in the Word. The consequence is proved: because he would be there as a thing spoken, and it is established that the whole world is spoken by the Word of God.

X. To these objections it is replied that being in an active principle occurs in two ways, namely extrinsically and intrinsically, that is, according to an operation that passes forth into something outside, and one that remains within. And that although being in an active principle extrinsically is a mark of imperfection, as in the case of being caused, nevertheless being in a principle intrinsically involves no imperfection whatsoever. Hence in the text the proof was taken from the fact that the word does not proceed outside the one speaking. – Reciprocity, moreover, is admitted even in extrinsic cases, so long as we grant that a cause exists in its effects by way of imitation or representation.

To the second, it must be said that the thing said is not one in manner only: for some thing is said essentially, while some is said representatively. The Father, therefore, is in the Son as a thing said essentially in the Word; but all creatures are said representatively, inasmuch as they are represented in God, whose Word essentially is, both as the thing said and as the speaker.