Og3 wrote: ↑
Thu Dec 06, 2018 5:51 pm
A meaningful and well-thought out reply.
So, my own studies in Physics have been relatively informal since 1984 (when I left a certain school of which we do not speak), but I can say without fear of contradiction that the Copenhagen Interpretation is the best answer thus far to the Quantum Mechanics equations. We could ignore QM altogether and insist that relativity is the right answer, as Einstein did in his latter days. Unfortunately, the great tide of experimental evidence would be against us.
I was told or read some years ago that while most physicists accept Copenhagen, most quantum cosmologists don't. And Quantum cosmologists are the relevant experts here. So you should have some fear of contradiction. As I understand it Einstein posited a deeper game where everything is still determined and as far as I'm aware that would still fit all the experimental evidence; in fact it may be a metaphysical theory that could never be contradicted by any evidence. And in choosing between theories, Copenhagen and many worlds could be the same.
Take, for example, the idea of Quantum Tunneling. Electrons sometimes go places they can't be. Or... Technically can't be. As a real world example, suppose that I had a non-zero chance of waking up in Toledo, Ohio, tomorrow. That non-zero chance would be predicated upon me travelling to Ohio, and then going to sleep there. But according to the idea of QT, I might sometimes wake up in Toledo without ever having gone there. Thank God I'm not an electron... Because that really happens to electrons. They pass through things that can't let them through. They appear places that they weren't going. So we have strong evidence by experiment that QT happens, and thus that CI is correct.
I am not convinced QT does prove Copenhagen and is not equally compatible with the other two options. It would seem so unless two thirds of quantum cosmologists have never heard of quantum tunneling or my data is now out of date and they have all changed their minds and come round to Copenhagen in the last decade.
So let's suppose then that Many World is correct, and for every electron that defies logic, there's another that behaves as expected in a different universe. Okay, the collapsing wave spawns a new universe identical to this one in every way, with every single electron interaction. Whatever universes are, there would be infinities of them, and they would be multiplying. This leads us into a problem when we consider the concept of multiverses: Infinite things are infinitely subdivided. Banuch Tarski paradox, that's your cue...
I don't see that infinite things would have to be infinitely subdivisible. Numbers have this property but matter is quantised, so it isn't. Nor would the infinite set of universes have to be related back to each other once they had divided, or so I understand it. Each universe could go its own way once the split had happened, so there isn't really anywhere all universes could exist as a set.
If we take something apart into an infinite number of pieces, we can construct two such things, identical in every respect with the original, from the infinite number of pieces of the original. So when we get to infinite universes, we have to abandon conservation, a fundamental principle of physics. In short, a multiverse, by definition, cannot be objective... It would have to exist as the result of subjective perceptions.
I am not sure a multiverse would need to be an object or even a set of objects.
(As an aside: wrt numbers, I accept the Peano Axiom set).
Well the Peano postulates are not complete as a number theory and are compatible with several philosophies of number, including Brouwer's radical version of constructivism, according to which numbers are not objects subject to logical laws.