Suppose two equally massive universes have an identical material substrate of the same fundamental particles. Suppose then that these two universes initially have different arrangements of these same matter particles. Is the set of arrangements that are reachable by the evolution of the first universe identical to the set of arrangements that are reachable by the evolution of the second universe? Note that I am assuming that the two universes are evolving indeterministically according to the known natural laws.
This question is related to an earlier question here: Is the set of reachable states of an indeterministic universe sensitive to its initial conditions?