9) Now, from computer science and logic, startlingly enough perhaps, we can isolate a measure on the 1-person comp histories, and this give us the laws of physics (this is too technical to be put here, and actually I have derived only the logical structure of the probability one, but I got something non trivial and very close to a quantum logic (which can be seen as the logic of the quantum probability one, as von Neumann has shown).
Bruno, I agree with everything in points 1-7 of the post I'm referring to. I think I understand the main thrust of points 8 and 10, but they both depend on the truth of the quoted point 9. I find this point highly dubious, and I'm interested to hear more about why you believe it (or whether I'm actually interpreting it correctly).
Is it your contention that if we start only with the idea of Platonia (which contains all possible computational structures and "events"), and we analyze the structure of all possible 1st-person histories weaving their way through this Platonia, we would see that a majority of them find themselves in universes like the one we currently inhabit, with stars, galaxies, relativity, quantum physics, etc.? I find that extremely hard to believe; there are an infinite number of multi-dimensional cellular-automata worlds that contain nothing like stars, galaxies, or the familiar physics we know, and I don't see any reason to believe that all the 1st-person histories weaving their way through these computational structures (which surely exist in Platonia) have less measure than those that weave through the structures more resembling our own universe.
I find it much easier to believe - in fact, it seems almost necessarily true - that, when we analyze the structure of all the 1st-person histories weaving their way through Platonia, we see that virtually all observers observe indeterminacy. This in itself seems like a non-trivial finding. It would be even more non-trivial if one could analyze the structure of the indeterminacy that virtually all 1st-person observers must observe, and find that it is very much like "quantum logic". This seems to be one of your claims, and it certainly seems possible (though I don't know enough yet to judge the issue for myself). However, it's a much further leap to conclude that we can go on to derive "the laws of physics" from the analysis of 1st-person histories weaving their way through Platonia. In the quote above, you acknowledge that you haven't actually done this - "actually I have derived only the logical structure of the probability one, but I got something non trivial and very close to a quantum logic" - but you seem to believe that it can be done. Why?