I did the whole sequence on QM to make the final point that people shouldn’t trust physicists to get elementary Bayesian problems right.
Unfortunately for your argument in that sequence, very few actual physicists see the interpretation of quantum mechanics as a choice between “wavefunctions are real, and they collapse” and “wavefunctions are real, and they don’t”. I think life set you up for that choice because you got some of your early ideas about QM from Penrose, who does advocate a form of objective collapse theory. But the standard interpretation is that the wavefunction is not the objective state of the system, it is a tabulation of dispositional properties (that is philosophical terminology and would be unfamiliar to physicists, but it does express what the Copenhagen interpretation is about).
I might object to a lot of what physicists say about the meaning of quantum mechanics—probably the smartest ones are the informed realist agnostics like Gerard ’t Hooft, who know that an observer-independent objectivity ought to be restored but who also know just how hard that will be to achieve. But the interpretation of quantum mechanics is not an “elementary Bayesian problem”, nor is it an elementary problem of any sort. Given how deep the quantumness of the world goes, and the deep logical interconnectedness of things in physics, the correct explanation is probably one of the last fundamental facts about physics that we will figure out.
Unfortunately this is a typical example of the kind of thing that goes wrong in philosophy.
Our actual knowledge in this area is actually encapsulated by the equations of quantum mechanics. This is the bit we can test, and this is the bit we can reason about correctly, because we know what the rules are.
We then go on to ask what the real meaning of quantum mechanics is. Well, perhaps we should remind ourselves that what we actually know is in the equations of quantum mechanics, and in the tests we’ve made of them. Anything else we might go on to say might very well not be knowledge at all.
So in interpreting quantum mechanics, we tend to swap a language we can work with (maths) for another language which is more difficult (English). OK—there are some advantages in that we might achieve more of an intuitive feel by doing that, but it’s still a translation exercise.
Many worlds versus collapse? Putting it pointedly, the equations themselves don’t distinguish between a collapse and a superposition of correlated states. Why do I think that my ‘interpretation’ of quantum mechanics should do something else? But in fact I wouldn’t say either one is ‘correct’. They are both translations into English / common-sense-ese of something that’s actually best understood in its native mathematics.
Translation is good—it’s better than giving up and just “shutting up and calculating”. But the native truth is in the mathematics, not the English translation.
In other words, the Born probabilities are just numbers in the end. Their particular correlation with our anticipated experience is a linguistic artifact arising from a necessarily imperfect translation into English. Asking why we experience certain outcomes more frequently than others is good, but the answer is a lower-status kind of truth—the native truth is in the mathematics.
Unfortunately for your argument in that sequence, very few actual physicists see the interpretation of quantum mechanics as a choice between “wavefunctions are real, and they collapse” and “wavefunctions are real, and they don’t”. I think life set you up for that choice because you got some of your early ideas about QM from Penrose, who does advocate a form of objective collapse theory. But the standard interpretation is that the wavefunction is not the objective state of the system, it is a tabulation of dispositional properties (that is philosophical terminology and would be unfamiliar to physicists, but it does express what the Copenhagen interpretation is about).
I might object to a lot of what physicists say about the meaning of quantum mechanics—probably the smartest ones are the informed realist agnostics like Gerard ’t Hooft, who know that an observer-independent objectivity ought to be restored but who also know just how hard that will be to achieve. But the interpretation of quantum mechanics is not an “elementary Bayesian problem”, nor is it an elementary problem of any sort. Given how deep the quantumness of the world goes, and the deep logical interconnectedness of things in physics, the correct explanation is probably one of the last fundamental facts about physics that we will figure out.
Unfortunately this is a typical example of the kind of thing that goes wrong in philosophy.
Our actual knowledge in this area is actually encapsulated by the equations of quantum mechanics. This is the bit we can test, and this is the bit we can reason about correctly, because we know what the rules are.
We then go on to ask what the real meaning of quantum mechanics is. Well, perhaps we should remind ourselves that what we actually know is in the equations of quantum mechanics, and in the tests we’ve made of them. Anything else we might go on to say might very well not be knowledge at all.
So in interpreting quantum mechanics, we tend to swap a language we can work with (maths) for another language which is more difficult (English). OK—there are some advantages in that we might achieve more of an intuitive feel by doing that, but it’s still a translation exercise.
Many worlds versus collapse? Putting it pointedly, the equations themselves don’t distinguish between a collapse and a superposition of correlated states. Why do I think that my ‘interpretation’ of quantum mechanics should do something else? But in fact I wouldn’t say either one is ‘correct’. They are both translations into English / common-sense-ese of something that’s actually best understood in its native mathematics.
Translation is good—it’s better than giving up and just “shutting up and calculating”. But the native truth is in the mathematics, not the English translation.
In other words, the Born probabilities are just numbers in the end. Their particular correlation with our anticipated experience is a linguistic artifact arising from a necessarily imperfect translation into English. Asking why we experience certain outcomes more frequently than others is good, but the answer is a lower-status kind of truth—the native truth is in the mathematics.
Yes they do. Experimentation doesn’t. Yet.