I think most physicists agree that at the bottom, we have a distribution of "complex amplitude"[1] over a "configuration space"[2]. But as you can see from my second link, many (most?) physicists insist that we can derive a "probability" from a complex number. Note that such probability would then be an actual real world probability, where the universe itself is uncertain about what to do. True non-determinism.
It's only natural. At the experimental level, the researcher does observe Born statistics. Same setup, different results, so there is probability in the territory after all.
There's a problem with that however: The equations, which make such wonderfully accurate predictions, (i) are dederministic, and (ii) do not state at any point that the blob of amplitude we don't see disappear in a puff of smoke. They merely say that the blobs eventually stop interacting. The same way that if you launch a photon to outer space, never to meet it again, it won't disappear the instant it reaches the boundary of our observable universe. If you insist on a mono world, you have to assert that the other blob, despite being predicted by those otherwise accurate equations, somehow doesn't exist when you don't see it.
One way to do it is to believe that, contrary to what the equations say, the blob you don't see does disappear in a puff of smoke. Its amplitudes are literally zeroed out behind your back. In hindsight, this one looks nuts to me. I mean, how can we justify distrusting accurate equations in a way that doesn't even make experimental predictions?
Another way is to call the square moduli of those amplitude "probabilities", and pretend that because it's probabilities, the blob you are not in isn't real. But the equations do not make any difference between the two blobs. Then how come the other blob is less real than our own?
To me, those two explanations really feel bizarre. You have to start from a mono world assumption to come up with that. An easy mistake to make, since personal experience is telling us all the time that there is only one world. A bit like a leaf in a binary tree: its ancestors form a line, not a tree. But Kolmogorov complexity says a literal interpretation of the equations (which means many world) is simpler than anything else we currently know about. So to hell with personal experience (which by the way is responsible for much worse whackery than mono world).
Now there is a way out: we can admit that current physics imply many worlds, but insist that real physics probably don't. Current physics are not complete after all. We may have big surprises. This argument is certainly be much saner than the Copenhagen interpretation. So much that it does lower my probability for many worlds somewhat. Just not enough to squash my confidence. :-)
Well, you probably guessed where I came from: http://lesswrong.com/lw/r5/the_quantum_physics_sequence/
I think most physicists agree that at the bottom, we have a distribution of "complex amplitude"[1] over a "configuration space"[2]. But as you can see from my second link, many (most?) physicists insist that we can derive a "probability" from a complex number. Note that such probability would then be an actual real world probability, where the universe itself is uncertain about what to do. True non-determinism.
It's only natural. At the experimental level, the researcher does observe Born statistics. Same setup, different results, so there is probability in the territory after all.
There's a problem with that however: The equations, which make such wonderfully accurate predictions, (i) are dederministic, and (ii) do not state at any point that the blob of amplitude we don't see disappear in a puff of smoke. They merely say that the blobs eventually stop interacting. The same way that if you launch a photon to outer space, never to meet it again, it won't disappear the instant it reaches the boundary of our observable universe. If you insist on a mono world, you have to assert that the other blob, despite being predicted by those otherwise accurate equations, somehow doesn't exist when you don't see it.
One way to do it is to believe that, contrary to what the equations say, the blob you don't see does disappear in a puff of smoke. Its amplitudes are literally zeroed out behind your back. In hindsight, this one looks nuts to me. I mean, how can we justify distrusting accurate equations in a way that doesn't even make experimental predictions?
Another way is to call the square moduli of those amplitude "probabilities", and pretend that because it's probabilities, the blob you are not in isn't real. But the equations do not make any difference between the two blobs. Then how come the other blob is less real than our own?
To me, those two explanations really feel bizarre. You have to start from a mono world assumption to come up with that. An easy mistake to make, since personal experience is telling us all the time that there is only one world. A bit like a leaf in a binary tree: its ancestors form a line, not a tree. But Kolmogorov complexity says a literal interpretation of the equations (which means many world) is simpler than anything else we currently know about. So to hell with personal experience (which by the way is responsible for much worse whackery than mono world).
Now there is a way out: we can admit that current physics imply many worlds, but insist that real physics probably don't. Current physics are not complete after all. We may have big surprises. This argument is certainly be much saner than the Copenhagen interpretation. So much that it does lower my probability for many worlds somewhat. Just not enough to squash my confidence. :-)
[1]: https://en.wikipedia.org/wiki/Probability_amplitude
[2]: https://en.wikipedia.org/wiki/Configuration_space