Quantum Measurement Cannot Be a Local Physical Process

Abstract

According to quantum mechanics, the outcome of an experiment exists relative to an Experimenter who performs a measurement on the system under study. Witnessing the outcome of an experience requires the measurement on a physical system whose size must match the complexity of the Experimenter’s observation. We argue that such a physical system must have a certain space-time extension so that it can encode the rich and complex data embedded in the witnessed experience. The complementarity principle in quantum mechanics leads us to conjecture that the observable events constituting an experience have space-like separation with each other. This seems to be in contradiction with our perceived locality of physical laws, and encourages us to think that the act of measurement is not a physical process, in the sense that a measurement outcome witnessed by an Experimenter is not necessarily related to the physical description of the Experimenter observed from the outside.