ManyMindsInterpretationsOfQM
https://www.ibiblio.org/weidai/Many_Minds.pdf
- 90 years after the discovery of modern QM, there is still no consensus as to how the theory should be understood. What is clear is that: "There are no conservative options."
- The extent to which QM super-positions are applicable to the macroscopic world lies at the heart of the problem.
- Quantum Holism: (eg an entangled state of the spins of two electrons) The whole state transcends the sum of its parts. Not only can the state not be reduced to states of the individual electrons, the two electron do not even have individual spin states.
- Entanglement has no classical antecedent and is UBIQUITOUS in QM. Virtually any interaction will lead in an entanglement of some kind.
- Hidden Variables: Bell demonstrated that if you assume hidden variables then they have to be non-local. ie: if the entangled electrons have independent hidden variables that lead to their correlated observations they must influence each other at faster than light speeds.
- Bell's Theorem has equally unwelcome consequences for a dynamical collapse theory. The collapse of one electrons wave function would have to propagate to the other at speeds larger than c.
- It seems widely believed that any realist interpretation of QM would have to be committed to a non-local interaction of some kind. But this is untrue. Once can avoid this implication by rejecting the assumption that when a measurement is carried out, *ONE of the possible outcomes occurs to the exclusion of all the others.
- It was Everett who first had the audacity to suggest that QM evolution is all that happens in measurement: the establishment of a quantum correlation between states of the electron and the apparatus, and Alice.
- Alice, we must conclude is literally of two minds. A remarkable conclusion, to say the least. But probably no more remarkable than the already utterly mysterious fact that, at a given time, there is even ONE "what it is like to be" associated with a brain. The very existence of consciousness is a complete enigma from the standpoint of physics.
- The term "Many worlds" seems to have been introduced by Bryce DeWitt
- From Deutsch: (Commenting on Lockwood)
- Despite the unrivaled empirical success of QM, the very suggestion that it may be literally true as a description of nature is still greeted with cynicism, incomprehension, and even anger.
- The 20C has been a veritable dark age for metaphysics – indeed it has been characterized by the explicit repudiation of metaphysics both by philosophers and by physicists.