  We analyze three important experimental domains (SQUIDs, molecular
interferometry, and Bose-Einstein condensation) as well as quantum-biophysical
studies of the neuronal apparatus to argue that (i) the universal validity of
unitary dynamics and the superposition principle has been confirmed far into
the mesoscopic and macroscopic realm in all experiments conducted thus far;
(ii) all observed "restrictions" can be correctly and completely accounted for
by taking into account environmental decoherence effects; (iii) no positive
experimental evidence exists for physical state-vector collapse; (iv) the
perception of single "outcomes" is likely to be explainable through decoherence
effects in the neuronal apparatus. We also discuss recent progress in the
understanding of the emergence of quantum probabilities and the objectification
of observables. We conclude that it is not only viable, but moreover compelling
to regard a minimal no-collapse quantum theory as a leading candidate for a
physically motivated and empirically consistent interpretation of quantum
mechanics.
