Summa Theologica, Part I (Prima Pars) / From the Complete American Edition

by Saint Aquinas Thomas

Reply Obj. 4: When anyone is said to work through anything, the converse proposition is not always true. For we do not say that the mallet works through the carpenter; whereas we can say that the bailiff acts through the king, because it is the bailiff's place to act, since he is master of his own act, but it is not the mallet's place to act, but only to be made to act, and hence it is used only as an instrument. The bailiff is, however, said to act through the king, although this preposition "through" denotes a medium, for the more a suppositum is prior in action, so much the more is its power immediate as regards the effect, inasmuch as the power of the first cause joins the second cause to its effect. Hence also first principles are said to be immediate in the demonstrative sciences. Therefore, so far as the bailiff is a medium according to the order of the subject's acting, the king is said to work through the bailiff; but according to the order of powers, the bailiff is said to act through the king, forasmuch as the power of the king gives the bailiff's action its effect. Now there is no order of power between Father and Son, but only order of 'supposita'; and hence we say that the Father spirates through the Son; and not conversely. _______________________

FOURTH ARTICLE [I, Q. 36, Art. 4]

Whether the Father and the Son Are One Principle of the Holy Ghost?

Objection 1: It would seem that the Father and the Son are not one principle of the Holy Ghost. For the Holy Ghost does not proceed from the Father and the Son as they are one; not as they are one in nature, for the Holy Ghost would in that way proceed from Himself, as He is one in nature with Them; nor again inasmuch as they are united in any one property, for it is clear that one property cannot belong to two subjects. Therefore the Holy Ghost proceeds from the Father and the Son as distinct from one another. Therefore the Father and the Son are not one principle of the Holy Ghost.

Obj. 2: Further, in this proposition "the Father and the Son are one principle of the Holy Ghost," we do not designate personal unity, because in that case the Father and the Son would be one person; nor again do we designate the unity of property, because if one property were the reason of the Father and the Son being one principle of the Holy Ghost, similarly, on account of His two properties, the Father would be two principles of the Son and of the Holy Ghost, which cannot be admitted. Therefore the Father and the Son are not one principle of the Holy Ghost.

Obj. 3: Further, the Son is not one with the Father more than is the Holy Ghost. But the Holy Ghost and the Father are not one principle as regards any other divine person. Therefore neither are the Father and the Son.

Obj. 4: Further, if the Father and the Son are one principle of the Holy Ghost, this one is either the Father or it is not the Father. But we cannot assert either of these positions because if the one is the Father, it follows that the Son is the Father; and if the one is not the Father, it follows that the Father is not the Father. Therefore we cannot say that the Father and the Son are one principle of the Holy Ghost.

Obj. 5: Further, if the Father and the Son are one principle of the Holy Ghost, it seems necessary to say, conversely, that the one principle of the Holy Ghost is the Father and the Son. But this seems to be false; for this word "principle" stands either for the person of the Father, or for the person of the Son; and in either sense it is false. Therefore this proposition also is false, that the Father and the Son are one principle of the Holy Ghost.

Obj. 6: Further, unity in substance makes identity. So if the Father and the Son are the one principle of the Holy Ghost, it follows that they are the same principle; which is denied by many. Therefore we cannot grant that the Father and the Son are one principle of the Holy Ghost.

Obj. 7: Further, the Father, Son and Holy Ghost are called one Creator, because they are the one principle of the creature. But the Father and the Son are not one, but two Spirators, as many assert; and this agrees also with what Hilary says (De Trin. ii) that "the Holy Ghost is to be confessed as proceeding from Father and Son as authors." Therefore the Father and the Son are not one principle of the Holy Ghost.