The One: How an Ancient Idea Holds the Future of Physics

by Heinrich Päs

In a move that would never have occurred to Bohr, she decided to take the film-roll reality seriously and even adopted it as “nature,” as more fundamental than the daily-life, on-screen reality. In doing so, Hermann made an important observation. She realized that the apparent causality violation experienced in quantum processes was nothing but an artifact of the on-screen reality: “Quantum mechanics has therefore not contradicted the law of causality at all, but has clarified it and has removed from it other principles which are not necessarily connected to it.”68 As von Neumann had already emphasized in his famous book, quantum mechanics consisted of two processes: first, the deterministic smooth evolution of quantum waves according to Schrödinger’s equation, and then the sudden indeterministic collapse during the measurement collapse. Now Hermann argued that quantum mechanics in fact provides the causal reasons for the state of an observed system, albeit only in relation to the specific observation, and that the nondeterministic feature was a property of the projection, not of the film roll.