Hi, I guess the Multiverse theory may be the wrong wording but I was thinking about the ideas seen on Science programs and in fiction where a decision made in this universe spawns a set of alternate universes to cover all possible decisions. I am sure you've seen the sort of thing - Pilot decides to shoot/not shoot at alien --- spawning a Universe at war with the aliens and a universe at peace --- or similar. My thinking on the scenario above is that an identical pilot in an identical situation will make an identical decision - ie. there never can be the possibility of two universes unless a deterministic process past->present includes random events. This idea comes from this thought experiment. Imaging an all powerful being who is capable of freezing this universe - stopping time- stopping everything. He then clones this universe and creates an exact duplicate. He then unfreezes these universes for 1ms and then stops both again and examines each for differences. For a macro sized event such as the pilot above I believe he will always make the same decision, in Universe(a) and Uni(b) his neurons are primed identically and I cannot figure any Macro event that will make a difference. So the question is what mechanisms do we expect to operate that will make these universes different to our detailed view. Anything that can be labeled deterministic cannot change things. My thinking (wild and woolly as it is) would suggest that only truly random events can make a difference and this descends into How do we know what is truly random against driven by a deterministic process we do not understand Every quantum twitch in the universe generates a new alternate universe (thats a lot of universes) An example would be a radioactive particle which decays/does not decay. Presumable this theory would expect alternate universes for this action. Can any one help me with this?