Reference [3] is a letter from Schrödinger to Lorentz. I would also argue that Einstein had one of the deepest understandings of QM at the time. Everyone knew t

Reference [3] is a letter from Schrödinger to Lorentz. I would also argue that Einstein had one of the deepest understandings of QM at the time. Everyone knew that the theory is weird, but with the EPR paper Einstein managed to pinpoint quite well where this weirdness shows up. It was also quite reasonable to assume that local hidden variables exist 40 years before a violation of Bell's inequality could be experimentally demonstrated.