To be sure, the task of showing that classical laws emerge to a good approximation in this manner is a nontrivial one, and it cannot be claimed that it has been completed. However, the effort expended thus far has not revealed any fundamental difficulty which would undermine this approach. One also expects to find cases in which the relevant quantum probabilities are not close to 0 or 1; in particular in a regime where classical analysis predicts chaos (positive Lyapunov exponents) quantum “fluctuations” are likely to be amplified. But this is also a situation in which the deterministic aspect of classical time development is not to be taken too seriously, due to the sensitive dependence upon initial conditions, so there is no reason to suppose that an appropriate quantum description cannot be constructed, at least in principle.