QUASI-CLASSICAL DYNAMICS IN A CLOSED QUANTUM SYSTEM

We consider Gell-Mann and Hartle's consistent histories formulation of quantum cosmology in the interpretation in which one history, chosen randomly according to the decoherence functional probabilities, is rea lized from each consistent set. We show that in this interpretation, i f one assumes that an observed quasiclassical structure will continue to be quasiclassical, one cannot infer that it will obey the predictio ns of classical or Copenhagen quantum mechanics.