Proof of a retroactive influence

Quantum theory predicts that, e.g., in a Stern-Gerlach experiment with electrons the measured spin component does not come about by an adjustment at the last moment, a forced flipping or tilting of the spin (vector), which would imply z-angular momentum exchange between particle and instrument, but will afterward appear to have had the value already before the measurement. Because an electron spin cannot have components in all directions at the same time, the measuring direction has a privileged status before the measurement, however we choose that direction, which implies a retroactive effect. A second proof of retroactivity is derived from a special case of the paradox of Einstein, Podolsky, and Rosen. It is strongly suggested by our result that, in essential respects, both Bohr and Einstein were right in their famous controversy about determinism and considering microprocesses as a whole.