  Recent developments point to a breakdown in the generalized second law of
thermodynamics for theories with Lorentz symmetry violation. It appears
possible to construct a perpetual motion machine of the second kind in such
theories, using a black hole to catalyze the conversion of heat to work. Here
we describe and extend the arguments leading to that conclusion. We suggest the
inference that local Lorentz symmetry may be an emergent property of the
macroscopic world with origins in a microscopic second law of causal horizon
thermodynamics.
