The approximations of classical mechanics resulting from quantum mechanics
are richer than a correspondence of classical dynamical variables with
self-adjoint Hilbert space operators. Assertion that classical dynamic
variables correspond to self-adjoint Hilbert space operators is disputable and
sets unnatural limits on quantum mechanics. Well known examples of classical
dynamical variables not associated with self-adjoint Hilbert space operators
are discussed as a motivation for the realizations of quantum field theory that
lack Hermitian field operators but exhibit interaction.Comment: 17 page