2: Further, He said: "No one knows the Son but the Father" (Mt. 11:27); which means that the Father alone knows the Son. But to know the Son is common (to the persons). Therefore the same conclusion follows.
Objection 3: Further, an exclusive diction does not exclude what enters into the concept of the term to which it is joined. Hence it does not exclude the part, nor the universal; for it does not follow that if we say "Socrates alone is white," that therefore "his hand is not white," or that "man is not white." But one person is in the concept of another; as the Father is in the concept of the Son; and conversely. Therefore, when we say, The Father alone is God, we do not exclude the Son, nor the Holy Ghost; so that such a mode of speaking is true.
Objection 4: Further, the Church sings: "Thou alone art Most High, O Jesus Christ."
On the contrary, This proposition "The Father alone is God" includes two assertions---namely, that the Father is God, and that no other besides the Father is God. But this second proposition is false, for the Son is another from the Father, and He is God. Therefore this is false, The Father alone is God; and the same of the like sayings.
I answer that, When we say, "The Father alone is God," such a proposition can be taken in several senses. If "alone" means solitude in the Father, it is false in a categorematical sense; but if taken in a syncategorematical sense it can again be understood in several ways. For if it exclude (all others) from the form of the subject, it is true, the sense being "the Father alone is God"---that is, "He who with no other is the Father, is God." In this way Augustine expounds when he says (De Trin. vi, 6): "We say the Father alone, not because He is separate from the Son, or from the Holy Ghost, but because they are not the Father together with Him." This, however, is not the usual way of speaking, unless we understand another implication, as though we said "He who alone is called the Father is God." But in the strict sense the exclusion affects the predicate. And thus the proposition is false if it excludes another in the masculine sense; but true if it excludes it in the neuter sense; because the Son is another person than the Father, but not another thing; and the same applies to the Holy Ghost. But because this diction "alone," properly speaking, refers to the subject, it tends to exclude another Person rather than other things. Hence such a way of speaking is not to be taken too literally, but it should be piously expounded, whenever we find it in an authentic work.
Reply to Objection 1: When we say, "Thee the only true God," we do not understand it as referring to the person of the Father, but to the whole Trinity, as Augustine expounds (De Trin. vi, 9). Or, if understood of the person of the Father, the other persons are not excluded by reason of the unity of essence; in so far as the word "only" excludes another thing, as above explained.
The same Reply can be given to OBJ 2. For an essential term applied to the Father does not exclude the Son or the Holy Ghost, by reason of the unity of essence. Hence we must understand that in the text quoted the term "no one" [*Nemo = non-homo, i.e. no man] is not the same as "no man," which the word itself would seem to signify (for the person of the Father could not be excepted), but is taken according to the usual way of speaking in a distributive sense, to mean any rational nature.
Reply to Objection 3: The exclusive diction does not exclude what enters into the concept of the term to which it is adjoined, if they do not differ in "suppositum," as part and universal. But the Son differs in "suppositum" from the Father; and so there is no parity.
Reply to Objection 4: We do not say absolutely that the Son alone is Most High; but that He alone is Most High "with the Holy Ghost, in the glory of God the Father."
THE KNOWLEDGE OF THE DIVINE PERSONS (FOUR ARTICLES)
We proceed to inquire concerning the knowledge of the divine persons; and this involves four points of inquiry:
(1) Whether the divine persons can be known by natural reason?
(2) Whether notions are to be attributed to the divine persons?
(3) The number of the notions?
(4) Whether we may lawfully have various contrary opinions of these notions?
Whether the trinity of the divine persons can be known by natural reason?
Objection 1: It would seem that the trinity of the divine persons can be known by natural reason. For philosophers came to the knowledge of God not otherwise than by natural reason. Now we find that they said many things about the trinity of persons, for Aristotle says (De Coelo et Mundo i, 2): "Through this number"---namely, three---"we bring ourselves to acknowledge the greatness of one God, surpassing all things created." And Augustine says (Confess. vii, 9): "I have read in their works, not in so many words, but enforced by many and various reasons, that in the beginning was the Word, and the Word was with God, and the Word was God," and so on; in which passage the distinction of persons is laid down. We read, moreover, in a gloss on Rm. 1 and Ex. 8 that the magicians of Pharaoh failed in the third sign---that is, as regards knowledge of a third person---i.e. of the Holy Ghost ---and thus it is clear that they knew at least two persons. Likewise Trismegistus says: "The monad begot a monad, and reflected upon itself its own heat." By which words the generation of the Son and procession of the Holy Ghost seem to be indicated. Therefore knowledge of the divine persons can be obtained by natural reason.
Objection 2: Further, Richard St. Victor says (De Trin. i, 4): "I believe without doubt that probable and even necessary arguments can be found for any explanation of the truth." So even to prove the Trinity some have brought forward a reason from the infinite goodness of God, who communicates Himself infinitely in the procession of the divine persons; while some are moved by the consideration that "no good thing can be joyfully possessed without partnership." Augustine proceeds (De Trin. x, 4; x, 11,12) to prove the trinity of persons by the procession of the word and of love in our own mind; and we have followed him in this ( Question [27], Articles [1],3). Therefore the trinity of persons can be known by natural reason.
Objection 3: Further, it seems to be superfluous to teach what cannot be known by natural reason. But it ought not to be said that the divine tradition of the Trinity is superfluous. Therefore the trinity of persons can be known by natural reason.
On the contrary, Hilary says (De Trin. i), "Let no man think to reach the sacred mystery of generation by his own mind." And Ambrose says (De Fide ii, 5), "It is impossible to know the secret of generation. The mind fails, the voice is silent." But the trinity of the divine persons is distinguished by origin of generation and procession ( Question [30], Article [2]). Since, therefore, man cannot know, and with his understanding grasp that for which no necessary reason can be given, it follows that the trinity of persons cannot be known by reason.
I answer that, It is impossible to attain to the knowledge of the Trinity by natural reason. For, as above explained ( Question
