If there is more than one "realm of existence", it should be considered part of our own, unless there is no intersection whatsoever, which there is. It's basically a way to avoid the issue. You invent a non-intersecting space, and say the laws don't apply there, so you can't ask how THAT got there.
Science can describe the universe to within a microsecond of it's formation. If it can't describe what went before that, perhaps that is because no evidence remains. That makes it more difficult for you to show a reason why any kind of complex being existed before that.
However, it also shows that something must have lead to the formation of our universe; I believe that to be God.