There are physical models which are not based on Quantum Mechanics, and are in fact incompatible with it. For example, to a physicist in the 19th century, a world that functioned on the basis of (very slight modifications of) Newtonian Mechanics and Classical E&M would have seemed very plausible.
The fact that reality turned out not to be this way does not imply the physical theory was internally inconsistent, but rather that it was incompatible with empirical observations that eventually led to the creation of the QM theory. So the point is that you cannot actually model nearly everything in conceptspace with QM, it’s just that reality turns out to be well-approximated by it, while (realistic) fiction like Newtonian Mechanics is not (for example, at the atomic & subatomic level).
This is what makes calling something a QM system an example of meaningful knowledge: it approximates reality better than it does something that is not real, exactly part of Your Strength as a Rationalist. By contrast, whatever story I give you, true or not, can be viewed as flowing from the Texas Sharpshooter Utility Function in exactly the same way that you said reality does:
All you have to do is define a utility function which, at time T, takes in all the relevant context within and around a given physical system, and assigns the highest expected utility to whatever actions that system actually takes to produce its state at time T+1.
So the fact that you “know” something is an EU maximizer, under OP’s definition of that term (which, as I mentioned above, is confused and confusing), does not constrain your expectations in any meaningful way because it does not rule out future world-states (because both true and false predictions are equally compatible with the EU process, as described).
By contrast, knowing something follows QM principles does constrain expectations significantly, as we can design self-consistent models and imagined future world-states which do not follow it (as I mentioned above). For example, the quantization of energy levels, the photoelectric effect, quantum tunneling, quantum entanglement, the anomalous magnetic moment of the electron, specific predictions about the spectra of atoms and molecules, etc., are all predictions given directly by QM; as such, the theory invalidates world-states in which we design proper experiments that do not find all of these.
But there is no articulable future world-state which is ruled out by OP’s conception of EU maximization.
There are physical models which are not based on Quantum Mechanics, and are in fact incompatible with it. For example, to a physicist in the 19th century, a world that functioned on the basis of (very slight modifications of) Newtonian Mechanics and Classical E&M would have seemed very plausible.
The fact that reality turned out not to be this way does not imply the physical theory was internally inconsistent, but rather that it was incompatible with empirical observations that eventually led to the creation of the QM theory. So the point is that you cannot actually model nearly everything in conceptspace with QM, it’s just that reality turns out to be well-approximated by it, while (realistic) fiction like Newtonian Mechanics is not (for example, at the atomic & subatomic level).
This is what makes calling something a QM system an example of meaningful knowledge: it approximates reality better than it does something that is not real, exactly part of Your Strength as a Rationalist. By contrast, whatever story I give you, true or not, can be viewed as flowing from the Texas Sharpshooter Utility Function in exactly the same way that you said reality does:
So the fact that you “know” something is an EU maximizer, under OP’s definition of that term (which, as I mentioned above, is confused and confusing), does not constrain your expectations in any meaningful way because it does not rule out future world-states (because both true and false predictions are equally compatible with the EU process, as described).
By contrast, knowing something follows QM principles does constrain expectations significantly, as we can design self-consistent models and imagined future world-states which do not follow it (as I mentioned above). For example, the quantization of energy levels, the photoelectric effect, quantum tunneling, quantum entanglement, the anomalous magnetic moment of the electron, specific predictions about the spectra of atoms and molecules, etc., are all predictions given directly by QM; as such, the theory invalidates world-states in which we design proper experiments that do not find all of these.
But there is no articulable future world-state which is ruled out by OP’s conception of EU maximization.