When you look in a mirror, and see what you think is a perfect reflection. You might be looking at a universe whose laws are fundamentally different.
Quantum mechanics tells us that the atom’s wavefunction can be in a superposition of states – simultaneously decayed or not decayed. So is the cat’s wavefunction also in a superposition of both dead and alive.
This video is about Bell’s Theorem, one of the most fascinating results in 20th century physics. Even though Albert Einstein (together with collaborators in the EPR Paradox paper) wanted to show that quantum mechanics must be incomplete because it was nonlocal (he didn’t like “spooky action at a distance”), John Bell managed to prove that any local real hidden variable theory would have to satisfy certain simple statistical properties that quantum mechanical experiments (and the theory that describes them) violate.
The idea of the multiverse — or the theoretical possibility of infinite parallel universes–straddles a strange world between science fiction and a plausible hypothesis.
Attempts to exempt speculative theories of the Universe from experimental verification undermine science, argue George Ellis and Joe Silk.