Eternity, essential and accidental attributes

The problem is this. If authority over the Son is an essential, not an accidental, attribute of the Father, and subordination to the Father is an essential, not an accidental, attribute of the Son, then something significant follows. Authority is part of the Father’s essence, and subordination is part of the Son’s essence, and each attribute is not part of the essence of the other persons. (Millard J. Erickson, Who’s Tampering with the Trinity: An Assessment of the Subordination Debate (Grand Rapid, MI: Kregel, 2009), 172)

When it comes to issues of time and eternity, issues of contention are very very difficult to be dealt with. Nowhere is this so when we talk about predication of God. Since God is eternal, does whatever God does in eternity essential to Him? This is the argument put forward by Millard Erickson against what he calls the "gradationist" position, now commonly called ESS (Eternal Submission of the Son). The problem when we deal with God in eternity is that we can come across some rather strange difficulties. Let us put the issue of ESS to the side for now. Rather, let us go back to the basics.

When we say that God the Father is the the Father, is Him being the Father necessary or contingent? Surely if we believe in immutability, we must say that God the Father is always God the Father, because there is not where the three persons mutually decided that one of them is the Father, the other the Son, and the last one the Holy Spirit. But if God the Father is always the Father, then is "being the Father" always part of the Father's essence, "being the Son" always part of the Son's essence, and each of these attributes is not part of the "essence of the other persons"? But, you object, there is only one essence in the Godhead. And you are perfectly correct. This is why Erikson's formulation of the supposed problem makes no sense, because what is of the persons is not necessarily predicated of the essence. The "unbegotten-ness" of the Father is not shared with the Son or the Spirit, but this does not imply that "each attribute is not part of the essence of the other persons."

The orthodox formula on the Trinity is: One undivided divine essence subsisting in three divine persons. It is an "unstable" formula, in the sense that it is not at all clear what that means, except that God is truly one, and yet truly three, in different senses. Since that is the case, predications of "necessity" and "contingency" are liable to fallacies. What does it mean for something to be an "essential" attribute of a person, if the person is not the essence (each divine person is fully God, but none of them are the essence apart from the other two)? If each person is distinct from the other, does that not imply that whatever is distinct is not shared between them, as "unbegotten-ness" is not shared with the Son and the Spirit?

This is not to say that there are no difficulties with saying that "authority over the Son is an essential, not an accidental, attribute of the Father." Rather, it is to assert that unless we can be clear about what we mean by "essential" when predicated of a divine person as opposed to the divine being, we cannot assume that the position known as ESS leads to ontological subordination of some kind.