But if every possible state at every moment in time spawns a universe, such universes can exist, can't they? There's a universe where Jessica Alba never pursued her acting career, and I didn't pursue my own. So we met at our other workplace. A friend of mine actually got accepted to that study abroad programme, where he met Emma Watson and then introduced me to her. Etc... etc... It's not physics defying, and not violating causality. Certainly there can't be universes with different constants, for example. But if it was ever possible that a random gene mutation turned the skin color of elephants blue, there is a universe with blue elephants.