I think you are perhaps confusing reality with the universe. The universe (according to one multiverse theory) is but one of many universes which contain their own laws of physics. Others say each universe is a membrane and universes are created when two membranes collide. When speaking of multiple universes, the word "reality" is perhaps a better word for talking about "everything".
From wikipedia:
From wikipedia:
Quote:The word Universe is usually defined as encompassing everything. However, using an alternate definition, some have speculated that this "Universe" is just one of many disconnected "universes", which are collectively denoted as the multiverse. For example, in bubble universe theory, there are an infinite variety of "universes", each with different physical constants. Similarly, in the many-worlds hypothesis, new "universes" are spawned with every quantum measurement. These universes are usually thought to be completely disconnected from our own and therefore impossible to detect experimentally.
