The Problem of Conscious Observation in Quantum Mechanical Description

Epistemological consequences of quantum nonlocality (entanglement) are discussed under the assumption of a universally valid Schrödinger equation and the absence of hidden variables. This leads inevitably to a many-minds interpretation. The recent foundation of quasi-classical neuronal states in the brain (based on environmental decoherence) permits in principle a formal description of the whole chain of measurement interactions, including the behavior of conscious observers, without introducing any intermediate classical concepts (for macroscopic “pointer states”) or “observables” (for microscopic particle positions and the like) — thus consistently formalizing Einstein’s ganzer langer Weg from the observed to the observer in quantum mechanical terms.