DJ Erock:
"The theory of the mutliverse as I know it is this. There are an infinite number of universes, containing an infinite number of possibilties. For example, there is a universe that is exactly like this one, only instead of this being called 'sciforums' its called 'philforums' or something like that. There are an infinite number of universes exactly like this one, except each one has a different name for sciforums. There are also an infinite number of universes where everything is exactly unlike this one, and infinite in-betweens."
Your conception of the theory is a bit flawed and probably - and I do not mean this offensively, so please, take none - a little flavoured by Science Fiction. That is to say, you are presenting to us the "Sliders" approach to the concept.
In and of itself, the Everett Many Worlds Interpretation of Quantum Mechanics (just MW for short henceforward) postulates that for every probalistic quantum calculation, each choice results in the formation of a separate universe, so if observer A was in universe A, and observer B in universe B, both would observe different things, but each would be -the only possible- result in their universe. That is to say, it is deterministic but convergent in different universes, as opposed to the strictly probablistic interpretations of other theories, and the consistant deterministic viewpoints of, say, Bohm's Theory. This, of course, does not translate into "there are a billion universes crewated when I move my hand", for hands are not suspectible to quantum effects, and there is a barrier where quantum effects, on all levels, seemingly become if not non-existent, irrelevant. In essence, the macroscopic world is all but immune to the weird behaviour of the Quantum Worlds, hence the discrepancy betwixt Quantum Mechanical models and Newtonian MOdels, although the latter almost completely explains macroscopic existence, excluding some aspects of Einstein's Theory of Relativity.
In essence: MW doesn't say that there exists parralel yous in other worlds doing slightly different things, but that in different universes, observations will be different of certain Quantum Observations, which may result in differences in what comes up, even to the point where parralel yous do not exist. Remember: We exist because of an pretty much infinite series of "happy accidents" that lead to our creation after billions of years of not existing. In essence, we are manifestations of a cosmic lottery.
"This would mean that in half of the infinite universes (I know you can't have half of infinity, I guess I mean one in every two), the multiverse doesn't exist. If you have a different universe for every possiblity, then a lot of universes contain the possibilty of not having a multiverse, just being a singular universe."
The traditional formulation of MW - which I am referencing - does not allow for there to be differences in the physical laws which govern universes, so that your result is impossible. Moreover, a possibility cannot be a possibility if it is not a possibility when that possibility is demanded to exist by prior possibilities. That is to say, if it is possible in our universes, and that possibility is manifest, then there cannot be a universe where it is not possible, and still that universe exists in the same "omniverse" as us. Either that or you pointed out one of the (many and varied) flaws of this (almost pseudo-scientifical) theory.
I am inclined to believe a bit of both.
I must also stress that there is no physical proof whatsoever of this theory being right at this persent time, and that besides that, that Quantum Mechanics and related topics (String Theories, et cetera) are possibly all wrong. That is to say, we must seriously consider that every single conjecture of theoretical physics is utterly wrong, and as it stands, all of them are, at least, would have something wrong in them, as only one model could be true, or another model not even thought of at the present time.
I postulate that we have at least 50 years to wait before any coherent theory will be presented that can be tested and shown to be true, and even then, I am skeptical. Specifically when scientists are abandoning many principles that have kept science going - consider that "dark matter" patches up holes in cosmological theory which do not account for the universe it is supposed to describe, or that scientists are throwing out the Law of Conservation of Energy in describing a universe which can spawn entire universes of created energy, or there being many different dimensions all bundled up and three expanded... - and we're somewhat at an impasse with scientific findings of certain things (we really do not have a clue how we can test some of these things), we might well be many centuries away from any true knowledge of the stuff we have happened upon and do not yet have an answer for.
But I digress...
whitewolf:
"The theory says that everything that can possibly happen does happen in the various universes. Non-existance is an existance that is not happening; how's that possible if everything that can happen does happen? The only way a universe can non-exist is if it does exist for a while and disappears. Sounds perfectly plausible to me. "
Wouldn't it more strictly be construed as "potential" or "possibility", not "non-existence" strictly?
Tyler:
"Man, I love Russell."
I do, too. Quite the good historian of philosophy and had some interesting philosophical and mathematical viewpoints, but I am afraid that his politics were terrible, and as a very public figure, somewhat make me dislike him as a man.
Of course, this is a tangent.
