This is actually a work-in-progress…
1. Take the cappadocian argument against Eunomius: Eunomius posited that there existed an intermediate energy between Father AND Son AND Holy Spirit. They correctly responded that within the essence there are no intermediaries. Yet if we look at the Photian monarchia of the Father–which I accept in its general outline–we see the Father “causing” the Son and Spirit. Since energia is functional with operation, and cause is an operation, how is this much different than the Eunomian claim? Fr Sergei Bulgakov beat me to the punch 100 years ago and offered a way out, but his ideas were condemned as heretical. Bulgakov notes that Photius accepted the same problematic as his opponents, nor could he escape the problem of diarchy: while the Filioque posits a two-ness with Father-Son on one side and Spirit on the other, Photianism (for lack of a better term), ends up with a similar two-ness, though consequent this time, as opposed to antecedent.
2. Dr Bruce McCormack illustrates some key gains with Cyril’s Christology. Like Apollinaris he understood that the Logos had to instrumentalize the human nature. Unlike Apollinaris he avoided truncating that human nature. The problem, though, as Lutherans were keen to pick up on, is locating the “acting agent.” Normally Cyril locates the acting agent as the Logos asarkos. However, when we get to the communicatio idiomata, it seems Cyril is locating the acting agent as the whole Christ, which is an entirely different term.
3. Orthodox and Lutherans hold to a real communication of attributes. Good. Here I part with the Reformed and proudly stand with Lutherans. There is a problem, though. St Maximus said the relationship was tantum…quantum. This means if there is a real communication, it’s a two-way street. However, if we attribute human attributes to the divine (which is how John Milbank reads Andrew Louth’s reading of Maximus), how can we seriously maintain any doctrine of divine impassibility?
4. Continuing McCormack’s argument. We admit that the person of the Logos is the acting agent of the union, denying activity to the human nature; this is consistent with the principle that persons act, not natures. However, when one communicates this to the modern world, using modern terminology, we find that we are equivocating on the term “human.” In today’s language humanity means, among other things, a self-activating nature.