Debating The Filioque and Incarnation: A Comparative Analysis of Eastern Orthodox and Thomistic Perspectives on the Trinity

The Eastern Orthodox claim that the three persons in the Trinity have the same divine will and power since they are the One God. However, if one does not affirm that they have the possibility of becoming incarnate then this would entail that they do not have the same power as only the Son has the power to become incarnate, while the Father and Holy Spirit cannot. If there are three persons who are each divine and yet share different powers then there is a strong argument that this leads to three gods rather than one. The idea that the Son alone has the power to become incarnate comes from Book 4 Chapter 4 of An Exposition of the Orthodox Faith by John of Damascus,

“The Father is Father and not Son: the Son is Son and not Father: the Holy Spirit is Spirit and not Father or Son. For the individuality is unchangeable. How, indeed, could individuality continue to exist at all if it were ever changing and altering? Wherefore the Son of God became Son of Man in order that His individuality might endure. For since He was the Son of God, He became Son of Man, being made flesh of the holy Virgin and not losing the individuality of Sonship.”

He argued that the Son’s individuality as the Son of God remains unchanged even when he becomes incarnate as the Son of Man. The individuality of each person in the Trinity is unchangeable. If the Son, who is eternally the Son of God, became incarnate as the Son of Man, it demonstrates the preservation of His individuality as the Son. The preservation of the Son’s individuality through the Incarnation implies that only the Son has the capacity to become incarnate while maintaining His identity as the Son. By extension, this suggests that the Father and the Holy Spirit do not possess the same capacity to become incarnate while preserving their individual identities. This interpretation relies on the premise that the incarnation uniquely pertains to the Son and is an expression of his individual identity as the Son of God. Therefore, it is argued that the Father and the Holy Spirit do not share the same capacity to become incarnate, as the incarnation is specifically tied to the Son’s individuality within the Godhead. If the persons, who are three instantiations of the divine universal, do not share the same powers then there would be three gods rather than one.

The Catholics, more specifically the Thomists, understand this problem and therefore have a solution to this conundrum. According to Thomas Aquinas’ Summa Theologica,

“It would seem that no other Divine Person could have assumed human nature except the Person of the Son. For by this assumption it has been brought about that God is the Son of Man. But it was not becoming that either the Father or the Holy Ghost should be said to be a Son; for this would tend to the confusion of the Divine Persons. Therefore the Father and Holy Ghost could not have assumed flesh. On the contrary, Whatever the Son can do, so can the Father and the Holy Ghost, otherwise the power of the three Persons would not be one. But the Son was able to become incarnate. Therefore the Father and the Holy Ghost were able to become incarnate” (Part 3, Q3, Article 5)

I believe that this can go for other powers as well such as the power to cause other divine persons. In Eastern Orthodox theology, they believe that the Father alone begets the Son and spirates the Spirit eternally and this is known as the monarchy of the Father. Contrast this with the filioque of the Catholics which states that the Spirit proceeds from the Father and the Son or through the Son. This doctrine emphasizes the unity of the Trinity in essence and power, as all three persons are involved in the procession of the Holy Spirit. Therefore, according to Catholic theology, there is no discrepancy in power among the persons of the Trinity. By the same logic of discrepancy in power this should lead to 3 gods as well in Eastern Orthodoxy. Again, according to Aquinas,

“In every action two things are to be considered, the "suppositum" acting, and the power whereby it acts; as, for instance, fire heats through heat. So if we consider in the Father and the Son the power whereby they spirate the Holy Ghost, there is no mean, for this is one and the same power. But if we consider the persons themselves spirating, then, as the Holy Ghost proceeds both from the Father and from the Son, the Holy Ghost proceeds from the Father immediately, as from Him, and mediately, as from the Son; and thus He is said to proceed from the Father through the Son. So also did Abel proceed immediately from Adam, inasmuch as Adam was his father; and mediately, as Eve was his mother, who proceeded from Adam; although, indeed, this example of a material procession is inept to signify the immaterial procession of the divine persons.” (Part 1, Q36, Article 3)

He explains that if we consider the power itself, there is no distinction between the Father and the Son since they share the same divine power. However, if we focus on the persons themselves as agents of the spiration of the Holy Spirit, Aquinas asserts that the Holy Spirit proceeds both from the Father immediately and mediately through the Son. He further goes on to state,

“If the Son received from the Father a numerically distinct power for the spiration of the Holy Ghost, it would follow that He would be a secondary and instrumental cause; and thus the Holy Ghost would proceed more from the Father than from the Son; whereas, on the contrary, the same spirative power belongs to the Father and to the Son; and therefore the Holy Ghost proceeds equally from both, although sometimes He is said to proceed principally or properly from the Father, because the Son has this power from the Father.” (Part 1, Q36, Article 3)

The Son does not receive a numerically distinct power for the spiration of the Holy Spirit from the Father. Instead, the same spirative power belongs to both the Father and the Son. This implies that the Son is not a secondary or instrumental cause in the procession of the Holy Spirit. Therefore, the Holy Spirit proceeds equally from both the Father and the Son, although it is sometimes said to proceed principally or properly from the Father due to the Son receiving this power from the Father. The Father and the Son are the one principle of the Holy Spirit but this is not the case in Eastern Orthodoxy which I believe results in three Gods while the Catholics fall into modalism as the persons are identical to the divine essence.