Not only is the very concept of submission out of step with the doctrine of the Trinity, it is also out of step with the divine redemptive acts for us in the economy of salvation. The incarnate Son’s act of kenosis or emptying consists in the assumption of a finite human nature. And, for us and for our salvation, Christ is qua his human nature obedient unto death to the will of the Father, which is just the one divine will shared among the Triune persons from all eternity. The Son’s obedience is not submission; it is faithfulness––acting in accordance with who the Son always and eternally was, is, and forevermore shall be.

Does eternal functional subordination undermine simplicity in the Trinity?

My short answer  is “Yes, it does.” In what follows I intend to suggest that the doctrine of divine simplicity—let’s call it DDS—requires a rejection of eternal functional subordination (EFS). I will sketch the basic contours of DDS and EFS and show that DDS and EFS are incompatible to the extent that EFS adds to the eternal personal properties of the Trinitarian persons.

While I think there are significant philosophical objections to DDS that ought to be taken seriously, I am at the very least friendly to the doctrine and think that unless one has significant biblical and theological reasons for rejecting a doctrine widely accepted in church history, then one ought to exercise caution in doing so. And so, for the purposes of this essay, I will assume that there is a defensible version of DDS.

Defining the Doctrine of Divine Simplicity

For the sake of this essay, I will assume that DDS means something like the version of the doctrine put forth in Thomas Aquinas’s Summa (1, q. 3). In this admittedly complex section of the Summa, Aquinas gives the following description of God: God is pure actuality; God is identical to God’s essence or nature; God is uncomposed (has no parts nor combination of matter and form); God’s nature is identical to God’s “suppositum”; God’s essence is identical to God’s existence. In sum, “it is clear that God is nowise composite, but is altogether simple” (ST 1, q. 3a7). There is much to be said about what motivates Aquinas’s account of DDS, but for the purposes of this essay, I am going to focus on Aquinas’s later claim in ST 1, q. 39 that “in God essence is not really distinct from person; and yet that the persons are really distinguished from each other.”

I take Aquinas to be saying that the divine persons are in some sense identical to the divine essence and in some sense not identical to one another. The former claim means that for each divine person the nature or essence that person possesses is the singular and numerically one divine nature; the Son’s divine nature is the Father’s divine nature and not merely a generic kind of essence like the shared humanity between you and me. The latter claim shows that despite sharing all and only the same essence, the persons are really distinguished––the Father is not the Son. I will return to these claims below.

I should note here that some proponents of EFS modify Aquinas’s account of Trinitarian persons as “relation(s) as subsisting in the divine nature” (i.e., as subsistent relations) by positing a more “social” doctrine of the Trinity. If these doctrines reject or are incompatible with Aquinas’s version of DDS outlined above, then they are not liable to my critique.

Defining Eternal Functional Subordination

Having outlined the contours of DDS, I want to do the same for EFS. Just two months in to my first semester at seminary at Trinity Evangelical Divinity, Tom McCall and Keith Yandell debated Wayne Grudem and Bruce Ware on the question “Do relations of authority and submission exist eternally among the Persons of the Godhead?” During that semester, I was in McCall’s class on the doctrine of the Trinity in Modern theology, and it quickly became clear to me that Grudem’s and Ware’s position lacked attestation in the Christian tradition, was out of step with Trinitarian doctrine in global perspective, and faced serious philosophical objections in terms of its compatibility with Nicene Trinitarianism. I formalized some of my arguments in the recent book Trinity without Hierarchy, edited by Scott Harrower and Michael Bird, and I intend to simplify, clarify, and expand them in what follows.

Before I criticize EFS, though, it is important to get clear on its basic commitments. First, proponents of EFS do not intend the Son’s subordination to the Father to be a subordination of essence or nature. It is functional, they say. The Father and the Son are equal in essence and distinct in person. Yet, lest one thinks that the Son’s submission to the Father’s will in redemption is mere playacting a role that could have been otherwise––a very Modern, dare I say Barthian (!) move––proponents of EFS stress that the submission is eternal. I take it that proponents of EFS want to stress that the subordination of the Son to the Father is non-arbitrary and reveals something in God’s revelation in the economy of salvation about the very life of God. The sociological motivation for this theological claim is often quite clear and equally unfortunate, given the close connection between EFS and the affirmation of so-called “complementarian” theology.

The Eternal Problem

The “eternal” component of the supposed submission of the Son has proven to be the sticking point in the debates for a variety of reasons. First, it is hard to make sense of what a non-essential yet eternal divine property could be. Perhaps it is like God’s electing decision to create and redeem, but we are told that the property of “being in submission” is supposed to be unique to the Son (and “being in authority” unique to the Father); the properties, in other words, are supposed to be personal properties––there are some unique characteristics of the Son and some unique characteristics of the Father, which help make sense of the divine missions in the history of redemption. But this is the rub, for on at least Aquinas’s account, the so-called “personal” properties are limited to the relations of origin that constitute the three divine persons of Father, Son, and Holy Spirit. As Aquinas puts it, “The three relations—paternity, filiation, and procession—are called personal properties, constituting as it were the persons” (ST 1, q. 30a2).

Read More