The Problem of Conscious Observation in Quantum Mechanical Description

H. D. Zeh

Published 1999-08-28, updated 2000-06-05Version 3

Epistemological consequences of quantum nonlocality (entanglement) are discussed under the assumption of a universally valid Schr\"odinger equation in the absence of hidden variables. This leads inevitably to a {\it many-minds interpretation}. The recent foundation of quasi-classical neural states in the brain (based on environmental decoherence) permits in principle a formal description of the whole chain of measurement interactions, including the {\it 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 {\it ganzer langer Weg} from the observed to the observer in quantum mechanical terms.