In the first volume we based quantum mechanics on the objective
description of macroscopic devices. The further development of the
quantum mechanics of atoms, molecules, and collision processes has been
described in [2]. In this context also the usual description of
composite systems by tensor products of Hilbert spaces has been
introduced. This method can be formally extrapolated to systems composed
of "many" ele- mentary systems, even arbitrarily many. One formerly had
the opinion that this "extrapolated quantum mechanics" is a more
comprehensive theory than the objec- tive description of macrosystems,
an opinion which generated unsurmountable diffi- culties for explaining
the measuring process. With respect to our foundation of quan- tum
mechanics on macroscopic objectivity, this opinion would mean that our
founda- tion is no foundation at all. The task of this second volume is
to attain a compatibility between the objective description of
macrosystems and an extrapolated quantum mechanics. Thus in X we
establish the "statistical mechanics" of macrosystems as a theory more
compre- hensive than an extrapolated quantum mechanics. On this basis we
solve the problem of the measuring process in quantum mechan- ics, in XI
developing a theory which describes the measuring process as an
interaction between microsystems and a macroscopic device. This theory
also allows to calculate "in principle" the observable measured by a
device. Neither an incorporation of consciousness nor a mysterious
imagination such as "collapsing" wave packets are necessary.