ekim,
The problem with that though is that it just posits this “observing entity” from nowhere. Complex or simple, it would presumably have to have enough complexity to perform the tasks you describe so how would any of that have come about? Our friend Mr Occam would suggest that adding more assumptions into the mix decreases the chance of finding the truth. Why not just stop at consciousness being an emerged level of complexity that sits on the layers of complexity beneath it all the way down to the neurons?
There’s an odd pattern here of people objecting to the hypothesis not because it’s non-congruent with the data and not because they have an alternative hypothesis that is congruent, but rather because it offends their sense of specialness (or in AB’s case because it undermines his personal model of reality).
Well, it goes on and on, with the immaterialists refusing to put forward any hypothesis of their own, as you say, that might be scrutinized and tested. I suppose if they did, it would be a bit limp - well, the soul just is conscious, or God does it, or something like that. Since they have very little, they spend most of their time attacking things like emergence, neuroscience, and so on.
It's a bit like the creationists attacking evolution, but never quite telling us how giraffes are made by the Big Man.
Hence, the large amounts of reverse onus, i.e. burden of proof.
