'Alternate universe' is a broad idea. If you think there are other universes outside the observable limits of our own, it is possible, but we're not likely to ever know. If you think there are alternate realities based on different probabilities and paths of space-time in the same universe (ex: a universe that is the same as this one except you were born a different gender, or one in which you turned out to have invented the toaster), then its possible, yet there is still no way to observable way to prove it. The second example is a major plot device in a lot of science fiction.
If you're still curious, there was one physicist, whose name eludes me, that provided a curious explanation to string theories requirements (which is related to this). The equation was found solvable only if higher values of dimensions than we now know existed. The values of dimensions were all higher than three or four, but more perplexingly, more than one amount of dimensions could be used as an answer. Seven, nine, ten were all possible according to the theory. How could the universe have anything but a set number of dimensions? In response to this inconsistency he said that all those values of dimensions are just different points of view of one single fundamental reality. Living on Earth before technology, people assumed the earth was flat (two dimensional) simply because it was flat under their feet. It isn't until we do some counter-intuitive brain work that we find out the earth actually isn't two dimensional. We can look at the universe through one scientific lens and see a distinct amount of dimensions, then look at it through another lens and see a completely different number. The fact that we can only experience and manipulate 3 dimensions and witness a still unproven dimension of time makes this very hard to understand.
Quote (Tummy @ Aug 22 2011 11:01pm)
in the end, what does anybody else's point of view even matter?
the only truth is what you believe to be truth, don't be swayed by anyone else.
there is no fact, only your perception.
If perception disagrees with reality in a repetitive and consistent fashion, its unity with truth will disappear. If one doesn't care and still clings to some belief regardless of what they actually see in front of them, its called neuroticism. The only ultimate judges we have to attest for personal truth are experiences.