PREFERRED CONSISTENT HISTORY SETS

The theme of this paper is the multiplicity of the consistent sets of histories emerging in the consistent-histories approach to quantum mec hanics. We propose one criterion for choosing preferred families among them: that the physically realizable quasiclassical domain ought to b e one corresponding to classical histories. We examine the way classic al mechanics arises as a particular window, and the important role pla yed by the canonical group and the Hamiltonian. We finally discuss a p ossible implication of our selection criterion: that only a class of H ilbert space operators corresponds to physical quantities, and hence t he full nondistributivity of the lattice of quantum propositions is re dundant.