Help Needed: Your opinions on the Many Worlds Theory

[kincuri]

I would like to request some assistance from fellow Sraffies.

My Nerdy Reason:
For my Quantum Mechanics course, I have been set an assignment to discuss a non-copenhagen interpretation for Quantum Mechanics. The second most popular interpretation (after copenhagen) is the many-worlds interpretation and with it's presence in HDM I would like to discuss it.

TROH forum seems to me to be a great place to gain some insight. Generally people have no idea about the interpretations of Quantum Mech. But this forum is full of people who have experienced a piece of literature that employs one of the concepts.

I would like to hear people's opinion of the Many Worlds Theory.
This is the concept that Pullman uses in HDM for the idea of multiple universes. Does it seem like an idea that could be possible in Real Life? This would include an infinite number of universes, each with it's own differences and variations. Each flip of a coin spawns two new universes, one where it lands on heads, the other tails etc.

If you are able to help me out before Friday (16/5), I will gladly make a donation towards hosting of bridgetothestars.net

Thanks!

[Bellerophon]

I think homework help may be against one of the Commandments, but if Pullman were around he might remind us that "thou shalt not" is soon forgotten.

Anyway, my criticism of this sort of hypothesis is twofold, and not at all original. First, the Many Worlds Interpretation doesn't make any testable predictions and I don't see how it could be falsified. It consequentially seems more akin to philosophy than science, and though that's not necessarily a bad thing I think it may limit its practical utility. Second, the Many Worlds Interpretation runs afoul of Occam's Razor. Why must there be many worlds to explain phenomena in this one?

That said, I obviously can't rule it out. See The Garden of Forking Paths by Jorge Luis Borges for an interesting take. Bear in mind that it was written in 1941. See here for the original Spanish.

[Philharmonic]

Definitely possible. Kinda like the string theory, there is no way to prove it right or wrong, but assuming-BIG ASSUMPTION HERE-that one day we will have time travel, we'd better pray it's right-cause if something happens that's big, like say you prevent Tony Blair from coming to office, or manage to prevent the Iraq war, it could mean big changes for the future, but the strange thing is, you know what happened-what happened before you went back happened-but now it hasn't, so there must be some other universe where it did.

I actually heard somewhere there's a book about a man who time-travels back to the dinosaur periods, and accidentally kills a butterfly. He goes back to the future and discovers the whole world is different-because of him.

But his old world still existed in his mind because he had lived there. So it must have existed.

I don't think a whole parallel universe theory is too unlikely.

[Quantum Reality]

The Many Worlds interpretation in quantum mechanics is quite wastefully extragavant in terms of the sheer number of universes you could create from each time a probability breaks out differrently across universes.

That having been said there is, in principle, no reason why not. I would argue, though, that perhaps the universes that 'split off' are so minutely diffferent as to be essentially unnoticeable if you were to go there, so is there any reason to suppose that our universe might not somehow 'reabsorb' those universes and only leave the major ones unaffected?

[kincuri]

Thanks to everyone for their responses so far.

I do agree with the idea that the theory could be considered overly elaborate. I can understand how the theory arose, but I think it would be a bit surreal for some people. I think that's why the Copenhagen has proven the most popular alternative.

I think homework help may be against one of the Commandments,

I thought that might be the case, but I would like to do a survey of peoples opinions to use as a reference, not getting them to do the assignment itself. I hope thats okay.

[AUST]

I don't know TBH-I'm no physcist but I read about it a bit. Much like the string theory its close to unprovable. That said, I like the idea and from what I read its possable (though there are a lot of prblems about the millions of worlds that would be created every second and the mechanics of it) so who knows-I certainly like it as it opnes up a lot of avenues for writing.

[Bellerophon]

I hope thats okay.

No worries mate, I was just kidding around. We're having fun here so I doubt the moderators will mind. Good thread.

I actually heard somewhere there's a book about a man who time-travels back to the dinosaur periods, and accidentally kills a butterfly. He goes back to the future and discovers the whole world is different-because of him.

I heard about that book too, but I didn't stop there. I read the hell out of it. See here.

[Philharmonic]

Perfect example-thanks for giving the link.

What happened to that future where Keith became president? It must have happened because thats where they left. A Sound of Thunder...not a good storyline, but interesting theory in it.

[Peter]

I hope thats okay.

No worries mate, I was just kidding around. We're having fun here so I doubt the moderators will mind. Good thread.

I actually heard somewhere there's a book about a man who time-travels back to the dinosaur periods, and accidentally kills a butterfly. He goes back to the future and discovers the whole world is different-because of him.

I heard about that book too, but I didn't stop there. I read the hell out of it. See here.

Also check out William Tenn's classic Brooklyn Project in which the human race, all unknowing, turns itself into something very different as a result of fiddling around with a time machine. I'm sure you'll be able to find it somewhere...

Also also check Larry Niven's Theory and Practise of Time Travel and its related stories in The Flight of the Unicorn / All the Myriad Ways, in which the grandfather paradox is neatly sidestepped by only allowing travel into the past of a parallel universe.

Also also also John Varley's Air Raid (and its extension into the novel Millennium (which was made into a crap film)) in which time travel into the past is allowed but only so long as inconsistencies are not created (and any period of past time is available to be visited once only). The future time travellers rescue people who are about to die in plane crashes.

And a neat story by Henry Kuttner / Catherine L Moore in which time-travelling tourists visit disaster areas for the sheer spectacle of it. Vintage Season - look it up. It was filmed (not badly) as Timescape / Grand Tour (1992).

And, and, also, also, Let's Go To Golgotha, in which the crowd around the Crucifixion turns out to have been entirely composed of time-tourists, who are only playing their part according to the script they've been given.

And, and, and, also, also, also Up The Line by Robert Silverberg, in which our intrepid traveller succeeds in impregnating his great-great-etc grandmother and has to be edited out of history. Not to mention Poul Andersen's Time Patrol stories in Guardians of Time.

There's lots out there

EDIT: updated and added a few details

[Ell]

I don't know a lot about the theories, but when I imagine time and multiple universes, I think of it like a salt crystal forming about a point. The point is the start of time and then as the universes split, there become more of them like the new layers of the salt crystal. And as the crystal grows it is getting a larger surface area representing the new universes split off through small changes. So each layer of the crystal represents a certain time after the start, and each molecule of the crystal represents a universe at a set time. Because I view it this way, I find it hard to believe in time travel and crossing between universes, because the crystal cannot stop growing and shrink back to a layer that formed earlier just as one molecule cannot move from one side of the crystal to the other one when it is bonded in place. And that is without considering the mechanics of moving the large group of atoms arranged into cells and organs that form our body to another place in exactly the same order.

Also, in order to believe that one choice produces a new universe, then you also have to believe two molecules bouncing off each other in a random manner will produce a new universe for every possible outcome every time it happens. And I accept what QR says about universes reabsorbing but if you consider at the big bang (if you believe it), the knock on effect of every slight collision between every particle in the universe, the number of possibilities is incomprehensible and the effect of each has the chance to make a relatively large change. But I suppose I could accept a salt crystal with an infinite surface area and ever growing bigger. If I really wanted to.

Oh and sorry if this is too late for you kincuri.

[kincuri]

Eli, the issue that you raise is a great point.

If many-worlds is correct, the number of universes created, even the shortest periods of time, is ridiculously huge.

After I handed the assignment in yesterday and was driving home, I was thinking about how it'd relate to HDM. Specifically to Will using the knife to open windows and searching for the "resonance" of the world he wished to enter.
In reality there would be an effectively infinite number of universes for him to search through and say, searching for Lyra's world, how can he be certain that the world he's looking for is the exact world that she originated from.

Time Travel into the future is theoretically possible, according to Einstein's Theory of Special Relativity, but it's like hitting fast-forward rather than being transported straight into a future time. Not so sure about traveling to the past.

oh wells, the mysteries of the universe...

Thanks everyone for their help!

[jessia]

because i don't know about the physics of reality, i can't talk about it in those terms. however, the many worlds theory always seemed perfectly reasonable to me as a thought experiment.. and just because we can only talk about in terms of a thought experiment doesn't make it less plausible as long as it's a well conducted thought experiment.

[Jez]

The philosopher David Lewis believes in concrete possible worlds as a grounding for modal logic.

[Roll_with_it]

Happy to help kincuri. I think that PWs are a possibility, but not quite in the way Pullman put across. As brilliant as it would be, it's just not happening. I was reading a book on the subject in Borders and the author suggested that the only possible way for them to exist would be on an other side of a wormhole which, as i'm sure you know, would be rather hard to get to. I like to think that it's real though, this passage from The Beach fueling many a class time daydream.

"Do you want me to tell you something funny?"
"What about? "
"Infinity. But it isn't complicated. I mean, you don't need a degree in -"
Francoise waved a hand in the air, tracing a red pattern with the tip of her cigarette.
"Is that a yes?" I whispered
"Yes"
"Okay". I coughed quietly. "If you accept that the universe is infinite, then that means there's an infinite amount of chances for things to happen, right?"
She nodded..
"Well, if there 's an infinite amount of chances for something to happen, then eventually it will happen - no matter how small the likelihood"
"Ah"
"That mean somewhere in space there's another planet that, by an incredible series of coincidences, developed exactly the same way as ours. Right down to the smallest detail."
"Is there?"
"Definitely. And there's another which is exactly the same, except that palm tree over there is two feet to the right. And there's another where the tree is two feet to the left. In fact, there're infinite planets with infinite variations on that tree alone..."
Silence. I wondered if she was asleep. "So how about that?" I prompted.
"Interesting" she whispered. In these planets, everything that can happen will happen"
"Exactly"
"Then in one planet, maybe I am a movie start"
"There's no maybe about it. You live in Beverly Hills and swept last year's Oscars".
"That's good"
"Yeah, but don't forget, somewhere else your film was a flop"
"Oh?"
"It bombed.The critics turned on you, the studio lost a fortune, and you got into booze and Valium. It was pretty ugly"
Francoise rolled on to her side and looked at me. "Tell me about some other worlds" she whispered.
"Well" I replied."That's a lot to tell"

[Ell]

I like that. It pretty much shows the scope of the principle, doesn't it.

[Cooroo]

I was disappointed by the Bradbury story (though it was good to have something to read!). I didn't for a moment believe that a) they wouldn't fully brief the 'hunters' before departure, b) the leader would deliver such a mammoth speech in conversation, c) that the ripples caused different spelling, different political climate, but still the same company with the same employees offering the same service.

I suspect I would have loved it 30 years ago, which makes me rather sad!

I do like the Many Worlds Theory. I don't know enough about the science, but it appeals to my imagination. But I did like someone's idea above the universes could get reabsorbed if the differences were sufficiently minor. My having a cup of coffee now or in 30 minutes time is unlikely to change the future of this universe (unless I have a huge role to play on this planet, and someone poisons the coffee in 30 minutes but not now, but I feel this is improbable!).

[darkchylde]

Schrodinger's cat. That stuff keeps me up at night, literally. I blame many sleepless nights on that damn theory.

Now, I wonder what would happen if you put Pavlov's dog and Schrodinger's cat in the same room....

[tellthemstories]

Quite honestly this is probably the most interesting area of science (in my opinion) because it allows you to think of anything and know its real, I like to think that the many worlds theory is true but never really anything about proving or disproving it. I don't think disproving it is even possible.

Why wouldn't it be a reasonable concept? Granted its impossible to visualise as its so packed with infinities but so is the expansion of the universe, what is reality? what is a void? thats the problem when we get to quantum physics, i don't think the human mind quite gets it. I certainly don't. But yeah, if an all powerful omnipotent omnipresent being is possible its a small thing to believe in parallel worlds.

Is Phillip Pullmans PW story possible? by basis of this theory its almost certainly true in an infinite number of universes (or an infinite number of an infinite number of parallel universes), its possible that will never returned to his exact same world, its quite probable that many wills didn't return to exactly the same world they left, but in this one instance of the story, he did. Why is he drawn to his home world, something about his reality I guess, what does it take to make us real? Who knows if any of this is real? He did, in his mind and thats how PP's theory works - to me anyway . Feel free to pick holes in the many opinions I have, there are quite a few, who knows if they are even my opinions?