If you have a sufficiently rapidly expanding universe, then there's sort of no limit to the amount of information you can put on. In mnkowski space, where there's no expansion of the universe, it can be infinitely big. Holographic principle can still apply, no problem. Every little vibration in one field is sort of sympathetically causing vibrations in all the other fields. All their combined feed backs lead to these interactions that you're talking about. Just have to keep up with what quantam fields are actually doing. Cunal menda says, how do you invision the many worlds interpretation winning out? Will it forever be an argument based on parsimony, or are there