Robert, it makes perfect sense. My own experience with Trinitarian theology (and Christology too, in its own way) was starting by thinking that these minds had really worked out what all these formulae meant at some deep level, and I was just a bit too slow to grok it. As time went on, I got ever more convinced that they really hadn’t, and that there was no more there than some rules about what it is permissible to say.

In some sense, it is as though the doctrines of the Trinity are some formulae of symbolic logic, in which variables are related to each other but never defined.

As long as you didn’t look too hard or press the hard questions, it all looked rigorous. But when you start pressing those hard questions, you always come up empty: It’s a mystery, you can’t understand it.

BJH: I’d love to hear more on this as it certainly piqued my curiosity.

Could you specify which part of it piqued your curiosity? It is the sort of casual comment that could quickly turn into a book if one took it seriously.

Well, for Sabellians the most direct support would be things in John, like, Jn 10:30, “The Father and I are one,” or Jn 8:58, “before Abraham was, I am,” Jn 14:9, “Who sees me sees the Father,” or even Jn 1:1, “and the Word was God”. But there were lots of other passages that could bear a Sabellian reading, like Col. 2:9 “For in him the whole fullness of deity dwells bodily” or the Christ hymn in Philippians or Heb 1:3.

For Subordinationists, you had passages like Jn 14:28, “The Father is greater than I,” Mk 13:32, Mk 10:18, but also things like 1 Cor 11:3, or anywhere that Jesus prays to the Father.

Orthodoxy reconciles them by taking from the Sabellians that Son is God and is the same one God that the Father is. From the Subordinationists it takes that the Father and the Son are distinct–the Father is not the Son and the Son is not the Father. But it also distinguishes: The Subordinationists are right that the Son is less than the Father, but only considered in his human nature.

You might put it this way: all three camps agreed that there was only one really truly fully divine God. The Subordinationsts insisted the Father was that God and the Son was distinct from the Father (by implication not that God). The Sabellians insisted Jesus was that God (and therefore he was the same one as the Father). The orthodox said it is both: The Son is both distinct from the Father and also fully that one true real God.

Not just mystical in a contemplative sense of a koan, but in a much more symbolic sociological sense. What was going on in the lives of the theologians and their communities that made this so meaningful to them. Why were they passionate about their differences

I think just believing that you are correct and the other guy is wrong is enough to explain a knock-down-drag-out fight. And once you have a fight it is easy for it to turn personal. Just look at the spats we have here on the forum. People will fight over anything.

Adding religious implications only heightens the stakes; e.g., the orthodox, during the Arian controversy, were concerned that the Eucharist could not divinize them if he whose body they received was himself a mere creature, however exulted.

what is it that unites a Muslamic modalist like Rahner with a Moltmannian tritheist liberation theologians seeking God in the struggle of their peoples against oppression?

I’m not sufficiently familiar with this unity to offer anything intelligent as a response. I would say that they seem to share some common ground in wanting the Trinity to have practical implications and a distaste for the scholastic systematization that leaves it a pure theory.

What is the meaning today in my life and relationships? Can I only genuinely respect the differences between us of those with whom I am open to being in a genuine relationship?

On the one hand, I can see how the trinity could be a fruitful seedbed for discussions of person-hood and relationality, and why, historically, it would be an important locus of such reflections. But given that I don’t feel bound by the doctrinal constraints, I don’t see why it should privilege that artificial framework over simply considering the relevant questions in their own right.

THE GODHEAD
The Nicene Creed became the central doctrine after the fourth century.
It Came To Pass by four centuries of subsequent descriptions of the Godhead disagreeing with every prior description of the Godhead.
The Roman Empire considered the Holy Trinity idea to be a more useful structure of government that would eventually replace paganism and Divine Emperors within itself.

THE INCARNATION
The Incarnation is found in John 1. The Grammar of Dionysios Thrax defines λογος as a Sentence. λεξις is a word. ** you do not have permission to see this link **
There are two kinds of matter: Spiritual and Flesh. The Sentence of Spiritual matter became Flesh of matter. The Sentence became Flesh. Hence the old English saying; would you like to come up here and say a word? (being invited to make a public statement that is obviously going to be longer than one single literal word.)

LIFE EVERLASTING & GRACE
That is all stated in the Nicene Creed. No questions asked and not even a syllable was to be added into the Creed afterwards, but it did as was called The Filoque which caused the schism between the Greek/Orthodox and Latin/Catholics.

The end. 🤷‍♂️