Further support for the positive effect of the separation of meaning from observability is given by Bell’s inequality ([Bell]{} [@Bel], [Clauser]{} et al. [@ClaHS]), a purely algebraic statement whose clarity is compelling, and the subsequent verification of its violation through experiments by [Aspect]{} [@Asp].

Finally, it seems that measurement problems can be adequately analysed by generalized observables defined as positive operator valued (POV) measures; see, e.g., [Davies]{} [@Dav], [Busch]{} et al. [@BusGL]. The gradual and approximate state reduction can be explained thermodynamically through dissipative interaction by the coupling to a macroscopic apparatus or heat bath; see, e.g., [Zurek]{} [@Zur], [Joos & Zeh]{} [@JooZ], [Ghirardi, Rimini & Weber]{} [@GhiRW].

That obtaining information about a system and state reduction are not equivalent things is a consequence of the possibility of nondemolition measurements ([Braginsky]{} et al. [@BraVT], [Kwiat]{} et al. [@KwiWH]) that produce knowledge about a system but (almost) avoid state reduction. And since the measuring apparatus necessarily involves a huge number of particles, any satisfactory solution of measurement problems should not be a part of the foundational concepts and these but be obtained as their [*consequence*]{}.

In an attempt to separate the discussion about the meaning of quantum mechanics from that of 