Wayfarer, I hope it's at least clear now that we do have a fundamental disagreement with your position, which was anticipated before. Especially the "inability to know the knower" which you posit in your 'iteration' of AI, and which Cleric quite comprehensively addressed in his illustration/metaphor.
Since you quote Schop's famous opening in that essay, I will share Steiner's response from PoF, as an addition to what Federica also shared.
Steiner wrote:This much, then, is certain: Investigation within the world of percepts cannot establish critical idealism, and consequently, cannot strip percepts of their objective character.
Still less can the principle “the perceived world is my mental picture” be claimed as obvious and needing no proof. Schopenhauer begins his chief work 6 with the words:
Schop wrote:The world is my mental picture — this is a truth which holds good for everything that lives and cognizes, though man alone can bring it into reflective and abstract consciousness. If he really does this, he has attained to philosophical discretion. It then becomes clear and certain to him that he knows no sun and no earth, but only an eye that sees a sun, a hand that feels an earth; that the world which surrounds him is there only as mental picture, that is, only in relation to something else, to the one who pictures it, which is he himself. If any truth can be asserted a priori, it is this one, for it is the expression of that form of all possible and thinkable experience which is more universal than all others, than time, space, or causality, for all these presuppose it ...
This whole theory is wrecked by the fact, already mentioned, that the eye and the hand are percepts no less than the sun and the earth. Using Schopenhauer's expressions in his own sense, we could reply: My eye that sees the sun, my hand that feels the earth, are my mental pictures just as much as the sun and the earth themselves. That with this the whole theory cancels itself, is clear without further argument. For only my real eye and my real hand could have the mental pictures “sun” and “earth” as modifications of themselves; the mental pictures “eye” and “hand” cannot have them. Yet it is only of these mental pictures that critical idealism is allowed to speak.
Critical idealism is totally unfitted to form an opinion about the relationship between percept and mental picture. It cannot begin to make the distinction, mentioned above, between what happens to the percept in the process of perception and what must be inherent in it prior to perception. We must, therefore, tackle this problem in another way.
...
From the foregoing considerations it follows that it is impossible to prove by investigating the content of our observation that our percepts are mental pictures. Such proof is supposed to be established by showing that, if the process of perceiving takes place in the way in which — on the basis of naïve-realistic assumptions about our psychological and physiological constitution — we imagine that it does, then we have to do, not with things in themselves, but only with our mental pictures of things. Now if naïve realism, when consistently thought out, leads to results which directly contradict its presuppositions, then these presuppositions must be discarded as unsuitable for the foundation of a universal philosophy. In any case, it is not permissible to reject the presuppositions and yet accept the consequences, as the critical idealist does when he bases his assertion that the world is my mental picture on the line of argument already described. (Eduard von Hartmann gives a full account of this line of argument in his work, Das Grundproblem der Erkenntnistheorie.)
The truth of critical idealism is one thing, the force of its proof another. How it stands with the former will appear later on in the course of this book, but the force of its proof is exactly nil. If one builds a house, and the ground floor collapses while the first floor is being built, then the first floor collapses also. Naïve realism and critical idealism is related as ground floor to the first floor in this simile.
I think you are misunderstanding the argument against critical idealism, based on your last comment, but I will let her respond first, and perhaps the above also helps clarify it.