Comments on my last post: Abandoning the use of the word history which seems confusing, when I said that a universe has an identifiable next state - since a universe was taken as being defined by its current state - I meant that the current state can identify a next state algorithmically - the algorithm may contain a pseudo random generator.
A universe which does not have an identifiable next state has no predictive algorithm because the universe's rules of state succession already tap true noise from the Everything. Since a universe rather winks out between states the identified next state need not be the one actually realized. This allows a bidirectional flow between the collection of universes with identifiable prior/next states and those without. I think some of this may help to unify several lines of thought on the subject. Hal