Also not really that interesting; I am not saying that J's only demands are control over his brain state, only that J has that demand.

Actually I've spent a lot of time contemplating this sort of thing. One of the things you must be very careful not to do is to give in to the temptation to continuously shift frames every time you arrive at anything resembling an answer to a question. The invitation to "ah, but what if...?" everything may feel all profound & stuff, but it is a path to persistent incomprehension, not understanding, because you can "what if...?" your way to anything, and therefore it has no actual information content.