Ok. Here's the thing though: Observables: There's one Universe.
   Any notion of more than one is based upon the mathematics. This
   does not negate the validity of the mathematics for mathematics
   sake but multiple Universes is a mathematical notion being
   applied as a possibility for reality WITHOUT a corresponding
   observation. This doesn't mean that it "might not be true". Of
   course it might be. But it's fictional. At present, it's
   fictional. This doesn't mean that it's not a good idea to pursue
   it. Someone just did a preliminary test on parts of the
   holographic Universe for example, which is a mathematical model
   and found no evidence as of yet. [I can find link but I'm
   guessing you've seen it. I can find it of course] Again, doesn't
   invalidate it. But there is a danger of analogies here:
   Mathematics is an analogy. It's a GREAT analogy. But it's
   analogy. There's also a strong belief system in place here: The
   grand unification of the Sciences with mathematics as its basis.
   That's not to say that it might not be true: it _might be_. But
   at present, it's not true. The gaps are wide between the
   Sciences. Perhaps they will be bridged one day. I hope they are.
   But to say "they are" is a belief... and a hope but currently a
   fiction. It's a good fiction, but it's a fiction.