A restricted form of Landauer's Principle, independent of computational
considerations, is shown to hold for thermal systems by reference to the joint
entropy associated with conjugate observables. It is shown that the source of
the compensating entropy for irreversible physical processes is due to the
ontological uncertainty attending values of such mutually incompatible
observables, rather than due to epistemic uncertainty as traditionally assumed
in the information-theoretic approach. In particular, it is explicitly shown
that erasure of logical (epistemic) information via reset operations is not
equivalent to erasure of thermodynamic entropy, so that the traditional,
information-theoretic form of Landauer's Principle is not supported by the
physics. A further implication of the analysis is that there is no Maxwell's
Demon in the real world.Comment: This version clarifies that the traditional, information-theoretic
form of Landauer's Principle is not supported by the physics; however, a
restricted form involving erasure of ontological uncertainty does hol