Everett tried to express his ideas as drily as possible, and it didn’t entirely work—he was still accused of “theology” by Bohr.
But there were and are technical issues as well, notably the basis problem. It can be argued that if you reify the whole formalism, then you have to reify the basis, and that squares the complexity of multiverse—to every state in every basis. The argument actually was by JS Bell in
Modern approaches tend to assume the multiverse has a single “preferred” basis, which has its own problems. Which tells us that it hasn’t always been one exact theory.
https://www.scientificamerican.com/article/hugh-everett-biography/
Everett tried to express his ideas as drily as possible, and it didn’t entirely work—he was still accused of “theology” by Bohr.
But there were and are technical issues as well, notably the basis problem. It can be argued that if you reify the whole formalism, then you have to reify the basis, and that squares the complexity of multiverse—to every state in every basis. The argument actually was by JS Bell in
Modern approaches tend to assume the multiverse has a single “preferred” basis, which has its own problems. Which tells us that it hasn’t always been one exact theory.