[wnoise]

The only point at which randomness enters is with "measurement" -- interaction with a classical system. But, if you believe in quantum mechanics, there is actually no such thing as a classical system, only large quantum systems.

[btilly]

And with that observation, you're into the Everett interpretation. Also called Many Worlds.

Namely that when an observer observes a quantum mechanical system, you get a quantum mechanical system that can be described as a superposition of parallel observers who each think that they saw something different. Those parallel observers cannot meaningfully interact thanks to thermodynamic considerations.

Of course accepting this description involves believing in quantum mechanics a little more than most feel comfortable believing in it...

[wnoise]

Yes. It's been my defaultish interpretation since I've learned quantum mechanics.

There is a wonderful lecture by Harvard Professor Sidney Coleman, called "Quantum Mechanics in Your Face"[1]. In it, he essentially leads into precisely this. It's what happens when you take quantum mechanics seriously.

My issue is that I can't take quantum mechanics seriously, or expect that it's interpretational issues can be sorted out within itself. The problem is that quantum mechanics is "merely" an extremely excellent approximation to quantum field theory. It can be thought of as an "effective theory" in a very similar way to QFTs as low-energy versions of other QFTs. Which means naturally that we should expect the framework of QFT to answer the interpretational issues, especially to provide guidance as to how the changes due to the approximations change the interpretation.

This is all a fine idea, but quantum field theories have even worse interpretational problems.

[1] https://www.youtube.com/watch?v=EtyNMlXN-sw