Do you believe in the "Many Worlds" interpretation of quantum mechanics...?

Question

That is, that there are an infinite number of universes, many of which have copies of us doing different things (i.e. in one universe, I am a Christian...uggg! - while in ANOTHER universe, I am a Buddist priest, and in a third I am a Hare Khrisna, etc., etc...)

Answer 1

Nah, that's an interesting thought, though. Besides, even if it were true, we couldn't see, interact with or communicate with them. It's really outside of the realm of science in that sense -- more of a metascience issue.

Answer 2

Everett's Many World's Interpretation (MWI) is a the only interpretation that both eliminates the role of the observer (thus eliminating a number of paradoxes such as EPR and Schrodinger's cat) as well maintains realism (something other decoherence models do not). This means that if you want physics to follow basic causality at a quantum level, you are stuck because nothing else right now cuts it. Bohm's Hidden Variable Interpretation has been blown apart by Bell's Inequality (for the most part), leaving little else.

That is why in several recent polls of leading quantum physicists, MWI has come out way on top (saw one that had a 60% "true" answer for the MWI).

Now some might say that it goes against Ockham's Razor, but that is because they are looking at the implications of the interpretation and not the mathematics. Actually all the decoherence interpretations have much more elegant math than the wave function collapse interpretations (e.g. Copenhagen) while providing more usable answers, and Bohm's Hidden Variable is fairly obviously against Ockham - it adds unevidenced forces unnecessarily (though arguably so does MWI, but I digress).

Now, the implications of MWI are a little hard to swallow, but as much as some physicists do not like to admit it, MWI does state that there are other "yous." If MWI is true, all possible quantum states occur at every instant - meaning there a potentially infinite number of "realities" branched from each other at individual quantum state changes. With inifinite possibilities, the probability of there being another "you" is 1 - in fact the probability of there being an infinite number of "yous" is 1 as well. Kinda makes your head spin, but that is the implication.

Now, just to make you feel better, you will never meet any of these other "yous" - nor will you ever be able to communicate with one - that is the stuff of science fiction.

Oh, by the way, for the guy above who thinks Hawking is the inventor or even a big proponent of MWI - you are wrong. Hawking has precious little to do with MWI or any other quantum interpretations. He isn't even a main popularizer of MWI - that title belongs to Deutsche (a colleague of Hawking's down the road at Oxford). Hawking is actually rather focused on black hole physics and actually has come up with Hawking-Hartle Radiation which showed convincingly that black holes radiate through particle pair annihilations. He actually is one of the few physicists older than a grad student who still contributes significantly beyond his pop-sci books (which although widely bought are rarely read and have contained things that were out of date by the time the books were printed).

Answer 3

Since the many worlds interpretation fails to make any unique predictions that differ from other quantum interpretations I would guess that the only valid criteria for deciding whether or not it might be true is Occam's Razor. It all boils down to which interpretation you think is more conceptually simple. Personally I think its simpler to assume that there is one universe governed by either chance or bizarre hidden laws, than to assume an infinity of complicated parallel universes that I can't ever observe. Especially since the parallel universes don't really add anything to the theory. I won't even mention the horrible philosophical and theological implications of this interpretation.

Answer 4

Too many people imagine that "many worlds" in quantum physics means whole separate worlds and realities, such as one with Al Gore as president, another with the Nazi Third Reich in world dominion, another still with Martians in control. Quantum physics frequently talks about a particle having "taken all possible paths", which people take to mean that somewhere in other worlds, I have decided to marry Girl X, I have decided to murder Girl X, I have decided to run off with Girl X's brother, etc. It's fun, it really does capture the public imagination, but the reality is a bit different.

Yes, it's true that particles and other microscopic things in quantum states do behave exactly as if they exist in vast numbers of parallel worlds, but that's only true for things in a quantum state. And it's very hard to have large objects in quantum states, such as the fabled Schrodinger's Cat, supposedly in a quantum superposition of being dead and being alive. The SLIGHTEST disturbance is enough to immediately cause a "state function reduction", in which EITHER the cat is alive OR it is dead, and no, it does not require some consciousness to make this happen. Quantum decoherence theory is taking care of the problem of "if a tree falls in the woods and nobody is around, does it make a sound?" (Yes, it does). it's possible to prepare a cat in a true quantum state, but it would require an ABSOLUTELY still, cold, and quiet space of enormous dimensions, and for any quantum interaction to occur would require more time than the life of the universe. It's the same thing that while it's true that a cup's quantum uncertainity makes it possible for it to spontaneously fall over, the odds of that happening is next to zero.

The concept of "parallel worlds", and "sum of histories" is a valuable one in quantum field theory, having yielded many excellent results thoroughly corroborated by experiment, but what needs to be reined in is the public fantasy of atlernate lives. No, there isn't another "you" that has lived life better or worse than you have.

Answer 5

The many worlds idea is a scientific hypothesis - it is not a proven theory - and as such, it is not a question of belief.

Furthermore, there would be nothing personal about it, no "you" existing as "you" in another world that is otherwise exactly the same as this one.

Science has its limitations, as science. What it doesn't show to be the case or cannot show to be the case, however, does not make those things a matter of religion: it only indicates where science is currently limited.

Answer 6

Indeed this is not a commonly espoused belief in modern cosmology. Put forth by the now disgraced Stephen Hawkings as a come back without significant mathematical support. Basically just a big imagination. It could be true!! But there is no mathematics at the present to support this. I liked Stephen Hawkings dont get me wrong. He should stick to the historical analysis of physics and teaching physics to young people rather than 1/2 time on that and 1/2 time trying to get a big hit in cosmology.

Answer 7

I think there are many aborted worlds, that choice brances do come off of this universe, but that they fade, loop, or merge after a very short period of time.

Answer 8

I'm pretty sure that is not part of the theory of quantum mechanics.