From the Universe to Subsystems: Why Quantum Mechanics Appears More Stochastic than Classical Mechanics.

By means of the examples of classical and Bohmian quantum mechanics, we illustrate the well-known ideas of Boltzmann as to how one gets from laws defined for the universe as a whole the dynamical relations describing the evolution of subsystems. We explain how probabilities enter into this process, what quantum and classical probabilities have in common and where exactly their difference lies. [ABSTRACT FROM AUTHOR]