Forgive my novice question; but, how does one explain the fact that decoherence doesn't contradict the evolution of the wavefunction in every world? Meaning, how is causality preserved in each world and what concept of time is professed wrt. to each world in the MWI? In other words, it seems like time is absolute and not relative with respect to each world in the MWI and decoherence being able to happen at all. Or am I understanding the wavefunction wrong here, as if it were multiple entities existing in each world and not one dictating the behavior of all worlds?