Great post as usual, Eliezer! I have to admit that I never thought of logical and causal references being mixed before, but truly that is often exactly how we use them.
I have one question, though: I read through the quantum physics sequence, and I just don’t understand—why are the Born probabilities such a problem? Aren’t there just blobs of amplitude decohering? Is the problem that all the decoherence is already predicted to happen, without implying the Born rule? If someone could clarify this for me, I’d greatly appreciate it.
I am not sure I am correct, but if I’m not mistaken, the problem with the Born rule is that no one so far has successfully (in the eyes of their peer physicists) proven they must be true. As in, they’re additional. If you go by the standard Copenhagen interpretation, since Collapse is already an arbitrary additional rule, it already sort of contains the Born probabilities: they’re just the additional rules that additionally condition how Collapse happens. But any other theories that remove objective, additional Collapse from the picture have this big problem: why, oh, WHY do we get the Born probabilities?
Furthermore, we have an even more interesting question: what do they even mean?! Suppose you (temporarily) accept the Born probabilities. What are they probabilities of? Meaning: if there is a 75% chance that you will observe a photon polarised in a given direction, what does that mean, in the grand scheme? Are you divided into 100 copies of you, and 75 of them observe such polarisation, while 25 of them don’t?
Great post as usual, Eliezer! I have to admit that I never thought of logical and causal references being mixed before, but truly that is often exactly how we use them.
I have one question, though: I read through the quantum physics sequence, and I just don’t understand—why are the Born probabilities such a problem? Aren’t there just blobs of amplitude decohering? Is the problem that all the decoherence is already predicted to happen, without implying the Born rule? If someone could clarify this for me, I’d greatly appreciate it.
I am not sure I am correct, but if I’m not mistaken, the problem with the Born rule is that no one so far has successfully (in the eyes of their peer physicists) proven they must be true. As in, they’re additional. If you go by the standard Copenhagen interpretation, since Collapse is already an arbitrary additional rule, it already sort of contains the Born probabilities: they’re just the additional rules that additionally condition how Collapse happens. But any other theories that remove objective, additional Collapse from the picture have this big problem: why, oh, WHY do we get the Born probabilities?
Furthermore, we have an even more interesting question: what do they even mean?! Suppose you (temporarily) accept the Born probabilities. What are they probabilities of? Meaning: if there is a 75% chance that you will observe a photon polarised in a given direction, what does that mean, in the grand scheme? Are you divided into 100 copies of you, and 75 of them observe such polarisation, while 25 of them don’t?
That’s… pretty much it. I hope I could help.