On Sun, Mar 6, 2022 at 6:57 AM Lawrence Crowell < [email protected]> wrote:
*> The issue is the extent to which there is subjectivity. * > Yes, I agree. *> With MWI we have this idea an observer is in a sense "quantum frame > dragged" along eigenstates corresponding to all possible measurements, but > is able to make a conscious account of only one.* > I would say an "observer" very quickly becomes the "observers", and every one of them is able to make a conscious account of the state they are in, *> This observer witnesses this [pre]-measurement state as a separable > state that is local.* > And another observer witnesses a post measurement state as a separate state that is local. *> However, if the observer is frame dragged along all possible paths* > One observer is not dragged along every possible path, instead one observer is duplicated enough times to fill all possible paths. > *there is a statistical ensemble of separable states, but we know this is > not a separable state in total. What is an account of a separable state is > then subjective to the observer.* > Yes, some states are so nearly identical that they make no subjective difference to the observer; for example whether a butterfly in Brazil flaps its wings 3 times or 4 makes no subjective difference to an observer in New York (or at least not for a while, in a few months due to chaos it might make the difference between a blizzard hitting New York and missing it, but that's another matter). If 2 brains are identical then they're producing 2 identical conscious experiences, and in that case I don't think it would be meaningful to say there are 2 observers. Some wonder if there are an infinite number of worlds how can Many Worlds get probabilities out of it, I think this is how, there may be an infinite number of worlds but there are only a finite number of beings who could reasonably call themselves "John Clark" or "Lawrence Crowell". *> This is to be compared to qubism, where the probability outcome is a > subjective Bayesian update.* > When calculating probability subjectivity cannot be ignored in the Many Worlds idea either. > *There are some things to be said for Qubism IMO, though it has some > almost solipsistic implications.* > Yes, and that's one of the things I dislike about Qubism. I take it as an axiom of existence that I am not the only conscious being in the universe, I can't prove it's true but I can prove that I need to believe it in order to function. > *> Qubism is a ψ-epistemic interpretation while MWI is ψ-ontological,* > Yes. > > *in that with qubism assigns no particular existence to the wave > function.* > That's another thing I dislike about Qubism, to me it seems uncomfortably close to the "shut up and calculate" school of thought. Many Worlds is the most straightforward explanation of what's going on, it's what you get if you just keep following Schrodinger's Equation and don't just arbitrarily shut it down for no apparent reason with a wave collapse. > *> The quantum wave of course has no operator assigned to it that gives an > eigenvalue, but there is the density operator ρ = |ψ〉〈ψ| that defines > probabilities. Probability is in qubism based again on Bayesian statistics > considers these subjective. With MWI the wave function is treated more as a > real, real in the existential sense than mathematical, object, but it is > highly nonlocal. This splitting off of worlds is not tied to any point in > space or spacetime* > If the only difference between universes is the number of times a butterfly flaps its wings and the question is how fast the universe splits because of that difference it could be thought of in 2 ways, which you choose as a matter of taste. You could say the split starts at the butterfly and spreads outward at the speed of light, or you could say the entire universe splits instantaneously, both ideas produce identical results with no way to differentiate between the two. *> At best either one uses the one which makes the best sense of some > problem, or you just "shut up and calculate." * > It seems to me if Einstein had just stuck with calculating Newtonian problems and hadn't even tried to think about how action at a distance could occur or about anything else that was actually going on he never would've found General Relativity. And "shut up and calculate" would turn science into an incredibly dull field of study.... when you changed the experimental set up of an experiment from state X to state Y the only thing you could conclude from that is that the reading on a voltmeter will decrease from 8 to 7, speculation on what was actually going on that could've caused that change would be forbidden. > *it all involves the issue to what extent the decoherence of quantum > states by coupling a larger quantum system (measurement apparatus or > observer) is at all computable.* > Some problems in pure mathematics are not computable, but there's no evidence that any of them have anything to do with physics, and in fact there is no evidence that nature even knows how to solve NP-hard problems in polynomial time. Quantum Computer expert Scott Aaronson actually tested this, and this is what he found: *" Taking two glass plates with pegs between them, and dipping the resulting contraption into a tub of soapy water. The idea is that the soap bubbles that form between the pegs should trace out the minimum Steiner tree — that is, the minimum total length of line segments connecting the pegs, where the segments can meet at points other than the pegs themselves. Now, this is known to be an NP-hard optimization problem. So, it looks like Nature is solving NP-hard problems in polynomial time!Long story short, I went to the hardware store, bought some glass plates, liquid soap, etc., and found that, while Nature does often find a minimum Steiner tree with 4 or 5 pegs, it tends to get stuck at local optima with larger numbers of pegs. Indeed, often the soap bubbles settle down to a configuration which is not even a tree (i.e. contains “cycles of soap”), and thus provably can’t be optimal.* *The situation is similar for protein folding. Again, people have said that Nature seems to be solving an NP-hard optimization problem in every cell of your body, by letting the proteins fold into their minimum-energy configurations. But there are two problems with this claim. The first problem is that proteins, just like soap bubbles, sometimes get stuck in suboptimal configurations — indeed, it’s believed that’s exactly what happens with Mad Cow Disease. The second problem is that, to the extent that proteins do usually fold into their optimal configurations, there’s an obvious reason why they would: natural selection! If there were a protein that could only be folded by proving the Riemann Hypothesis, the gene that coded for it would quickly get weeded out of the gene pool." * > > *The shut-up-and-calculate approach might be compared to the Euclid 5th > axiom that is not decidable,* > Euclid's 5th axiom might be decidable, not through mathematics but through physics and astronomy, and the best evidence we have so far is that it's true, the universe seems to have no overall global curvature. A better example might be the Continuum Hypothesis because that involves infinite sets and it's not clear if real physical lines actually do contain an infinite number of points, it's not even clear if an infinite number of anything that's physical exists. > *I am not particularly an upholder of any interpretation of quantum > mechanics.* > I'm not either really, I'm just saying Many Worlds is the least bad explanation of Quantum Mechanics that I know of, maybe tomorrow somebody will find a better one. But whatever the truth turns out to be there is one thing I feel certain of, it will be weird. John K Clark See what's on my new list at Extropolis <https://groups.google.com/g/extropolis> lqc -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/CAJPayv3mgm703WBnZXbhBqSZpk-dQdMp9WDN5P%2B-ASE9AFRdLA%40mail.gmail.com.
