If the Many Worlds Interpretation of quantum theory holds, then there are essentially infinite universes. In fact, there would a very huge sort of infinities of universes. If it's based upon the idea that every possibility of every quantum particle interaction instantiates itself in another universe, that's zillions created in every fraction of a second. It can only make sense that these universes overlap, otherwise I'm creating a universes outside of this universe, each a universe away just by typing. So if the universes overlap that means there is interference from every universe impinging on every other universe at once.
Taking the example of the Moravec thought experiment. If it's a one in a million chance that you don't die from the electric chair, then in one universe you are alive but in a million others you are dead. (technically speaking 999,999 vs 1). So you're never really dead, you are mostly dead with the accumulated weight and energy of 999,999 universes keeping you dead. It is the momentum of the accumulated likely universes that keeps time flowing in one direction and preserves causality. And so it makes sense to say that the momentum of the zillions of likely universes converge reality into a single path objects in which can only escape that overwhelming force at the quantum level.
I think of it as what happens if the Washington Monument toppled over and fell flat on top of you. Well, it's a fact that there is a .50 bullethole in one face of it that was never repaired. When the monument falls, that part of you that fits in the bullethole is not dead, and was never touched.