Which suggests that the current doctrine isn't inevitable but could be different?
Well inevitable in its fundamentals, the question of how the Father, Son and Spirit relate to each other, as stated and implied in Scripture.
But I have been looking at the Aramaic term 'memra', which means 'word', but is closely associated with God 'the memra of God' in the Targums seems to suggest aan autonomous agency akin to our 'Word' or 'Logos' in John ... in short, what would have happened if John had said "In the beginning was the Memra, and the Memra was with God, and the Memra was God" (John 1:1).
Rather my point was the Platonic triune doesn't possess enough significant markers to call it 'proto-Trinitarian'.
Where the ideas do coincide is when theologians, seeking ways to explain or demonstrate the belief in a coessential Father-Son-Holy Spirit is both reasonable and rational (as much as any discussion of the nature of the Divine can be), looked to Platonism as a beneficial framework to begin to construct a coherent theory.
"
That it is especially with the Platonists that we must carry on our disputations on matters of theology, their opinions being preferable to those of all other philosophers." – Augustine of Hippo, City of God, VIII,5.
Plotinus’ (204–270) had a triune of the One, Intellect, and Soul, the latter two emanating from the One, being "the One and not the One; they are the one because they are from it; they are not the One, because it endowed them with what they have while remaining by itself" (
Enneads, 85). Plotinus uses terms such as
hypostases and describes their sameness by
homoousios, terms from the philosophical lexicon that the Fathers used in formulating doctrinal definitions, and which in the case of the latter caused such a stink at Nicaea in 325.
Augustine says that he and others of his day believed the Neoplatonists had some awareness of the persons of the Trinity (
Confessions VIII.3;
City of God X.23).
+++
Enshrined in the Platonism of Plotinus is the mystical ascent of “the alone to the alone”, that absolute simplicity of the One, the source and origin of all, in a cascade of necessary emanations, a triune of the One, the Intellect and the World Soul, and to which everything must necessarily return.
Christianity reveals God as a personal Tri-unity that creates
ex nihilo as an utterly free and gratuitous act, and furthermore deigned to enter history as an incarnate, flesh-and-blood being.
Stated as such, the two are irreconcilable.
+++
Further, in the Trinity, God is one
ousia (essence) in three
hypostases (for simplicity's sake, 'persons')
, as opposed to the Platonic doctrine of the absolute simplicity of the One.
Historically, attempts at overcoming the apparent opposition of Christianity's Tri-unity to an utter simplicity of the One inescapably lapse into some manner of heresy – be it modal Sabellianism, hierarchic Arianism, or a flat denial of the Tri-unity itself, Unitarianism.
+++
Here we have a philosophical problem – that of 'the one and the many'.
How do we account for individuality of beings, grounded in the transcendence of the Christian God or the Platonic One, without reducing God to simply the ontological first among the many within the created order (pantheism), or the negation of creation in light of the infinite difference, which opens up a chasm between what God is and what all other beings are (deism).
The key, as many theologians currently declare, is that God, the One, is
perfectly one and yet simultaneously
relational.
Christianity – Catholicism and Orthodoxy – has strayed somewhat from that vision. The first signs, as I read them, occur around the end of the first millennium (we'd have to go into Sacramental theology to tackle that one – too big a divergence, I fear), but gathered pace from then on, and took further catastrophic steps away with the (anti-mystical) Reformation.
Somwe argue, and I would agree, that to recover a mystical, metaphysically-coherent contemplation of the nature of the Trinity is to look once more not at those sources that fed into the discourse in the first place – Platonism – and revive that dialogue anew.
Such being the case, an investigation of the
Enneads of Plotinus will show how a metaphysical intimations of
the Trinity are there, as well as how Plotinus’s philosophical framework and lexicon provides a set of principles that can be 'fleshed out', 'embodied' or indeed dare I say 'transfigured' by the Doctrine of the Trinity.
Also what little I know about Plotinus -- wasn't he somebody who believed in an indivisible one? Therefore more Unitarian?
I don't think we can say that, as Unitarianism is specifically Christian based.
Was his work about Christian doctrine or not? I don't remember his time period (I need to look up)
Nope. He was the culmination of Platonism.