  Time-symmetric cosmological theories, in which the initial and final states
are arranged to have similar features or are independently fixed, have been
quite extensively discussed in the literature. However, a more general and
perhaps more useful possibility seems, surprisingly, never to have been
considered. Quantum cosmology, like any inherently probabilistic dynamical
theory, can be modified by conditioning on the occurrence of a sequence of
cosmological events fixed a priori and independently of the hamiltonian and
initial state. These more general theories provide a natural class of
alternatives which should eventually be useful in quantifying how well the
hypothesis that initial conditions suffice is supported by the data.
