Quantum Reality: Beyond the New Physics

by Nick Herbert

“A coupling even with a measuring device is not yet a measurement. A measurement is achieved only when the position of the pointer has been observed. It is precisely this increase of knowledge acquired by observation that gives the observer the right to choose among the different components of the mixture predicted by theory, to reject those which are not observed, and to attribute henceforth to the object a new wave function, that of the pure case which he has found. We note the essential role played by the consciousness of the observer in this transition from the mixture to the pure case. Without his effective intervention, one would never obtain a new Ψ function … Thus it is not a mysterious interaction between the apparatus and the [quantum] object that produces a new Ψ for the system during measurement. It is only the consciousness of an ‘I’ who can, by virtue of his observation, set up a new objectivity.”