Granted I strictly shouldn't use the word "theory" without being backed up by evidence, but there are many theories expressed today in such manner. One good example is the string theory. It’s yet to be proven, probably incorrect but is still a theory. If it makes you happy I would replace theory with conjecture, if I could.
As for the other universes, well that’s being bounced amongst astrophysicists and cosmologists. Gee, we hardly know a thing about our vast universe so how the hell can we postulate about others, if they exist at all? Pure conjecture for now.
