My assumption is that we have a primal self - which could also be called our real, true or divine self; and it is this which is eternal, and has existed from eternity. My primal self is "encased" within a mortal and temporarily-incarnated self; which is (approximately) our body and our personality - that which other people observe, and which interacts with The World.
The process called theosis describes the transformation of my primal self, across a timescale of eternity; but at present intended to be achieved by interaction-with, and learning-from, the experiences of my mortal self in this world.
So -- if I succeed in my God-given task of learning from the experiences God has set-up for me in this mortal world; then it is my primal self that is positively-transformed by this learning.
And it is this process of positive transformation of the primal self that can be called theosis.
This model may explain why it is that theosis is not necessarily (or usually) observable in a Christian individual.
Dr. Charlton’s post started me thinking about the nature of “learning from the experiences God has set up for me in this mortal world,” and I have arrived at a tentative intuition -- the bulk of the mortal life learning that directly impacts the primal self is probably non-symbolic, or more precisely beyond the symbolic (as far as I know, Dr. Charlton has more-or-less stated the same on his blog).
During our mortal lives, we rely on symbols to serve as intermediaries between the subject and reality. Put another way, symbols – including language – point us in the direction of reality without being reality themselves.
Well-motivated interpretations of symbols can help orientate us toward the truth and direct us to what we need to learn and understand; however, the essence of that learning and understanding must transcend the symbolic and be directly known.
The primal self is positively transformed by experiences of direct knowing – not the symbols that may have guided us to the experiences of direct knowledge.
This may help to explain why “what is happening is that the primal self is being transformed positively and eternally - but the bodily behavior and actions, and personality level motivations and thoughts; are Not (or not usually) being transformed.”
Symbols may lead us to experiences of direct knowing, but it is difficult to imagine how direct knowledge can be “translated back” into the symbolic without losing its essence, or why this process would even be necessary.
As noted above, this is a tentative intuition; however, I believe it may warrant some consideration, particularly when we factor in our current milieu of accelerated and ubiquitous symbol corruption, i.e., the expropriation, subversion, and inversion of symbols as intermediaries between subjects and reality, most frequently via the promulgation of the symbolic as reality (exacerbated by the increased use of AI and other virtuality technologies).