Craig Blomberg has a pretty detailed review of Philip Payne's Man and Woman, One in Christ: An Exegetical and Theological Study of Paul's Letters, and because of Denver Journal's new comment feature there's a lengthy comment in reply by Payne right below the review. There's a brief statement in Blomberg's review that Payne spends a good deal of time responding to that caught my interest.
The primary debate is over a particular issue in biblical interpretation between complementarians who insist that functional subordination is compatible with ontological equality when it comes to human relationships and egalitarians who resist such a compatibility. Most complementarians consider a similar kind of functional subordination to occur between the Father and Son in the Trinity, and so any egalitarian argument against it has to take into account both levels of the analogy, which makes things tricky to say the least. My own concern with Payne's argument lies primarily in its significance for the Trinitarian debate, but it also has an application in the gender-role issue that gave rise to the overall book that Blomberg is reviewing. I'll quote the relevant part of the exchange before offering my sense of where I think Payne's argument is mistaken.
Payne finds the concept of functional subordination within ontological equality virtually non-sensical
This misrepresents my position. I believe that ontological equality is perfectly compatible with functional subordination as long as that subordination is voluntary and temporary, as was Christ's voluntary and temporary subordination to the Father in the incarnation (e.g. Phil 2:6-11). It seems to me that if subordination in necessary and eternal, it is then an aspect of one's essence. As Millard J. Erickson says in Who's Tampering with the Trinity? An Assessment of the Subordination Debate (Grand Rapids: Kregel, 2009), 250, "If the Father is eternally and necessarily supreme among the persons of the Trinity, and if the Son eternally is subordinated to him, an interesting consequence follows. The Son in not merely accidentally, but essentially, subordinate to the Father. That means that there is a difference of essence between the two--that the Father's essence includes supreme authority, while the Son's essence includes submission and subordination, everywhere and always." It is the simultaneous affirmation of equality of essence of the persons of the Trinity with this sort of difference in their essence that I find self-contradictory.
I'm not sure I agree. It depends on a couple issues. In the case of the Trinity, it partly depends on what you mean by "ontological equality". Suppose functional subordination is correct, and the Son is functionally subordinate to the Father eternally and necessarily. Does that imply ontological inequality? Well, it implies a difference that is ontological, if it counts as an ontological difference for the Son to have an essential property not shared by the Father and the Father to have one not shared by the Son. If the roles are eternal and necessary (meaning there is no possible world in which the Father and Son don't have these roles), then there is an ontological difference, yes.
But is it inequality? Only in the sense that two things that are different are not equal on the mere ground that they are different. An apple and an orange are different and thus not equal. But they're an apple and an orange and are thus not comparable. It's not as if the apple is superior to the orange or vice versa just because they're different fruits. They're just different. Ah, but isn't the hierarchical relationship of the Father and Son going to be comparable, since one is in authority over the other? Thus it won't be like apples and oranges. That's true. But what the apple-orange relationship illustrates is that you can have differences without having the kind of ontological difference that amounts to inequality. Does a hierarchical relationship involve the kind of inequality we should care about when talking about equals?
Not necessarily. In the congregation I grew up in, the pastor and chair of the elder board was an unpaid volunteer, who had a full-time job in the human resources office of a local manufacturing plant. A member of the congregation was the human resources director and thus was his boss. So they simultaneously were in authority over each other in different respects, one on a spiritual level and the other in a workplace-supervisory role. Each was functionally subordinate to the other. It's true that in this case both are temporary roles, but my point with the example isn't that it's permanent but ontologically equal. It's that a functionally-subordinate role relationship can be hierarchical without being unequal. These two men were fully equal in their rights as U.S. citizens, as members of our congregation, and as employees of their company, but in certain respects one was in authority over the other, while in other respects the other was in authority over the first. So a hierarchical relationship can involve functional subordination with ontological equality.
So it seems to me that functional subordination is compatible with equality in the important sense, and whatever sense ontological differences of the sort Payne points out will be true in a case of eternal and necessary ontological differences, it's not the sense that undermines the relevant kind of equality.
But I think there's another problem with Payne's argument. Should we assume that eternal functional subordination implies necessary subordination? Should we think eternal functional subordination of the Father to the Son involves some essential property of the Father involving authority and a different essential property held by the Son involving subordination? I'm not sure myself that such a view would be heretical, as Kevin Giles claims. As long as the property is relational, it need not be part of the essence of the Father or the essence of the Son (which on traditional orthodox assumptions should be the same essence and thus have the same properties). After all, there has to be something that distinguishes the Father from the Son for them to be two persons, even if they are also the same God and thus can't have essential properties that are different. Perhaps an essential relation between them, a functional one rather than an ontological one, that would do that trick. (By a relation here, I mean a property corresponding to a two-place predicate that's held between two things rather than a property corresponding to a one-place predicate held by one thing.)
But you might instead be able to make sense of the Father-Son relation as contingent but eternal. In other words, isn't it possible that the functional relationship between the Father and Son is a voluntary, agreed-upon relationship that the Father and Son eternally and timelessly settle on but that in another possible world they might have eternally and timelessly settled on a different relation, namely one that puts the person who actually is the Father in the Son role and the person who actually is the Son in the Father role? I'm not aware of anything in the creeds or the scriptures that precludes such a view. Something's being true at every time certainly does not imply that it had to be true. If that truth is grounded in a timeless decision that God might have made differently, then in a different possible world God would have had some other contingent fact true of him timelessly and eternally. So it simply isn't true that functional subordination across all time implies necessary functional subordination.
I think there's yet a third problem too. Complementarians think functional subordination relations among human beings in this life should not involve a woman in authority over a man in marriage or in spiritual authority over men in the church. Regardless of whether that view is correct, I don't think it's true that they hold this to be true eternally. Marriage relationships end in death, and there's no reason to think elder-congregation relationships continue with any authoritative relationship post-death. So, for the only two functionally-hierarchical relationships most complementarians today even believe in, there's no reason to think complementarians must extend those relations beyond death, and thus that functional subordination isn't even an eternal relation, never mind a necessary one. I'm sure most complementarians would insist that women will not be in authority over men in the resurrection in any way like the husband-wife or elder-member relations in this life. But that doesn't mean such relations will continue. It's consistent with complementarianism that no human being (besides Jesus) will have any authority over any other human being in the resurrection. So even if Payne were right that eternality implies essentiality (which he certainly is not), he'd have the further problem of extending his critique toward complementarians who won't even insist on eternal functional subordination, and I don't see why complementarians should insist on that.