The problem with this is the universe is no longer causal. Events can happen which cause themselves. It requires you to try every possible universe and then "throw away" the ones that aren't consistent. And if you simulate a universe, doesn't it cause that universe to exist, even if you later decide you don't like it? Who is to say we don't exist in one of the many "throw away" universes vs the one where the particle causes itself to be consistent.
More on that here:
http://lesswrong.com/lw/fok/causal_universes/