You’ve been playing low-stakes poker with a bunch of buddies for years. You might peek at someone’s cards now and then, but only as a joke. Suddenly your buddy accuses you of cheating. Shocked, you exclaim, What the hell! It’s just a game! Chill out! Something like that just happened in the field
I think that one of the most common ways by which the devotees of reductive physicalism try to make it appear to be a valid position is by positing a false dichotomy by which they then sneeringly characterize anything that’s not simply physical as “mystic.”
The fact that it’s an emergent phenomenon with no physical manifestation.
I think we’ll be able to (and in fact we already can to some notable degree) track neuronal activity in a brain and map it and interpret it, so we can make reasonably solid guesses regarding its nature - general type, intensity, efficiency and so on - but we can never actually observe its content, since its content is a gestalt formed within and only accessible to the mind that’s experiencing it.
There’s nothing at all “mystic” about that - it’s simple logic and reason.
And, by the bye, it’s also much of why actual philosophers rejected reductive physicalism almost a century ago.