  Quantum dynamics can be regarded as a generalization of classical
finite-state dynamics. This is a familiar viewpoint for workers in quantum
computation, which encompasses classical computation as a special case. Here
this viewpoint is extended to mechanics, where classical dynamics has
traditionally been viewed as a macroscopic approximation of quantum behavior,
not as a special case.
  When a classical dynamics is recast as a special case of quantum dynamics,
the quantum description can be interpreted classically. For example, sometimes
extra information is added to the classical state in order to construct the
quantum description. This extra information is then eliminated by representing
it in a superposition as if it were unknown information about a classical
statistical ensemble. This usage of superposition leads to the appearance of
Fermions in the quantum description of classical lattice-gas dynamics and turns
continuous-space descriptions of finite-state systems into illustrations of
classical sampling theory.
  A direct mapping of classical systems onto quantum systems also allows us to
determine the minimum possible energy scale for a classical dynamics, based on
a localized rate of state change. We use a partitioning description of dynamics
to define locality, and discuss the ideal energy of two model systems.
