Consistent-histories Description of a World with Increasing Entropy

1. Attempt at a self-contained quantum description The consistent-histories program 1,2,3 represents a more concerted effort than previous attempts to overcome what some workers regard as the main defect of the Copenhagen interpretation: the need to invoke the existence of a classical world as a precondition to the meaningful interpretation of quantum mechanics. Hence, just as for any other attempt at a self-contained quantum description, the first order of business for this program is to represent the classical world correctly. It is precisely on this point, however, that the consistent-histories program has not yet been carried to completion to the satisfaction of all concerned. It is not the purpose of this note to discuss the nature of the difficulties encountered; rather, assuming that there is a quantum description of the quasi-classical world along the lines of consistent-histories, I ask what the description will be like. In particular, I investigate the rule of association between the histories in a suitable family and the quasi-classical worlds that the formalism is supposed to describe.