Endovelico wrote:Nothing gives me a sense of impotence and inadequacy even remotely close to what I feel in the presence of quantum physics. Not even those times when I couldn't achieve an erection while in bed with a beautiful female... If there is a measure of absolute ignorance, my understanding of quantum is it.
A lot of the mind boggling stuff re quantum mechanics seems to be caused by some very misleading jargon used that started with the Kopenhagen [not Heisenberg
) interpretation, in line with how Richard Feynman summarized the situation as referenced by Typhoon:
One might still like to ask: “How does it work? What is the machinery behind the law?” No one has found any machinery behind the law. No one can “explain” any more than we have just “explained.” No one will give you any deeper representation of the situation. We have no ideas about a more basic mechanism from which these results can be deduced.
We would like to emphasize a very important difference between classical and quantum mechanics. We have been talking about the probability that an electron will arrive in a given circumstance. We have implied that in our experimental arrangement (or even in the best possible one) it would be impossible to predict exactly what would happen. We can only predict the odds! This would mean, if it were true, that physics has given up on the problem of trying to predict exactly what will happen in a definite circumstance. Yes! physics has given up. We do not know how to predict what would happen in a given circumstance, and we believe now that it is impossible—that the only thing that can be predicted is the probability of different events. It must be recognized that this is a retrenchment in our earlier ideal of understanding nature. It may be a backward step, but no one has seen a way to avoid it.
We make now a few remarks on a suggestion that has sometimes been made to try to avoid the description we have given: “Perhaps the electron has some kind of internal works—some inner variables—that we do not yet know about. Perhaps that is why we cannot predict what will happen. If we could look more closely at the electron, we could be able to tell where it would end up.” So far as we know, that is impossible. We would still be in difficulty. Suppose we were to assume that inside the electron there is some kind of machinery that determines where it is going to end up. That machine must also determine which hole it is going to go through on its way. But we must not forget that what is inside the electron should not be dependent on what we do, and in particular upon whether we open or close one of the holes. So if an electron, before it starts, has already made up its mind (a) which hole it is going to use, and (b) where it is going to land, we should find P1 for those electrons that have chosen hole 1, P2 for those that have chosen hole 2, and necessarily the sum P1+P2 for those that arrive through the two holes. There seems to be no way around this. But we have verified experimentally that that is not the case. And no one has figured a way out of this puzzle. So at the present time we must limit ourselves to computing probabilities. We say “at the present time,” but we suspect very strongly that it is something that will be with us forever—that it is impossible to beat that puzzle—that this is the way nature really is.
He basically is saying that computing probability is all we have and that it is the end of the road. And we have no idea he says, what type of mechanics can produce such results.
Statements like "The ultimate nature of reality is probabilistic" you will encounter a lot, however. From there it is only a small step to people going on a imaginary bull ride introducing "information" to the nature of reality and getting totally wild from there even saying things like "consciousness drives reality". Or that with every collapse of a wave function somewhere on the quantum scale.. a whole new Universe is created.. so that in the end zilquadrodonian many worlds are branching out into infinity.
To what physical reality can something like "the probability distribution" refer to? Is there some "probability distribution" existing in reality when there are no people around tossing with those concepts and doing QM measurements? Feynman actually admits that he has no idea what physical reality or mechanism is able to produce the (extremely accurate) results of QM.
"The collapse of the wave function" is one of those cliffhangers. The wave function is a mathematical description so when it "collapses" I suspect something weird to happen to the paper it is written on?!
Or do they mean the wave pattern as observed in for instance the double slit experiment that "collapses" into a particle type of behavior when it is measured passing through the slit creating a dot instead of an interference pattern? But given that Feynman has no idea what type of mechanism can produce QM measurements as predicted by the QM formalisms.. it would be cheating to suggest that what actually happens in the experiment is equally "probabilistic" in nature as the formalisms that describe it.
Einstein is well known to have had serious problems with those assumptions. "God doesn't play dice" etc. (Added the funny rhetoric response of Nils Bohr: "Don't tell God what to do"
)
I tend to think that the weirdness of QM and the suggestiveness of a probabilistic nature of reality (for which there really is zil proof - read Feynman carefully) is a similar case as the struggle with consciousness: how to squeeze/explain conscious experience from "observed physical behavior". Both are "dead ends": in the case of consciousness the phenomena is explained backwards (try to explain fire forwards in time when you start with smoke...ain't gonna work), and in the case of QM the fact there seems to be no mechanism thinkable able to produce the results... could also mean that "probability" is more like a byproduct of animating a number of assumptions of poor quality.
The math and predictions can be perfect and it is quite possible to not know why it all works. That is reasonable humility. To claim however that the nature of reality is probabilistic too just as the QM formalisms are... is of course doing the opposite of what Feynman suggests. He just says that QM does not tell you much about the nature of reality, but since QM computes damn well.. lets just compute and not philosophize too much about what it means.