Is anyone here an ardent "Many Worlds" advocate? I've always had a problem accepting the idea and had some questions...
Can you give us a link to what you consider a good definition of "Many Worlds"? A starting point might avoid some confusion as the thread gets going. Just a suggestion Please Register or Log in to view the hidden image!.
Yeah, ok. I figured if I said "what it was" I would get someone claiming that I have it wrong. Anyway here's what wiki has to say, and this is my understanding as well... I'm bringing this up because the MWI was mentioned in another thread as a potential solution (by me, actually) to the QM vs SR paradox.
The other problem with a wiki reference is that I fear it will basically frame (and limit) the discussion...
Don't have a strong opinion on MWI, but no thread on the topic should be allowed to persist without bringing up Quantum Immortality.
Here is a link to quantum suicide and immortality that I just looked at that gives the basics: http://en.wikipedia.org/wiki/Quantum_suicide
Yeah, definitely take a look at the Wikipedia page. The idea is that if there exists some universe wherein every possible outcome occurs, there will always be some universe in which any event that could result in your death will not end up actually killing you. And since your consciousness presumably does not inhabit any universe in which you are dead, it follows that you will percieve yourself as living for ever. The funny part of this is that you can challenge people who subscribe to MWI to put their money where their mouth is and shoot themselves in the head. If they are correct, they should find that doing this fails to kill them. Although they will still be dead in the universe you inhabit... The reason this is interesting is that it raises interesting questions about the role of consciousness in qm.
Excellent input. You live forever in some state, but it is the quality that matters. Just thought I would throw that in.
Yes, it is an interesting link. Follow the link to Max Tegmark too for some interesting additional background. "He developed the quantum suicide thought experiment from earlier proposals by Hans Moravec and Bruno Marchal, and has come up with a mathematical argument for the multiverse. He has also been a strong critic of those who would infer a theory of consciousness from quantum effects, such as Roger Penrose and Stuart Hameroff."
Yeah, a detail that gets glossed over in Quantum Immortality is that just because some event doesn't kill you does not imply that it doesn't do grevious damage to you. And since there is no obvious conncetion between consciousness and injury, there is no reason to expect that quantum suicide wouldn't leave you wishing you could die :]
In some parallel universe, Hans Moravek is busy publishing papers documenting his empirical proofs (complete with video!) of quantum immortality. I wonder how he got ethics clearance?
Maybe he is still trying to get clearance, but if he has a potentially infinite number of tries, certainly he will slip through the screen.
Hmmm, a problem I have with Quantum Immortality is that each of us has also experienced everyone possible excruciating death that is conceivable to experience due to the MWI of QM. Quantum Immortality is interesting but it's consequences shouldn't influence our decision on the "ultimate solution" of QM just because we like the idea of being immortal.
Well, that wouldn't be "us", that would be consciousnesses that diverged from ours. Quantum immortality seems to be based on consciousness being strictly derived from our past worldline, and (obviously) only continuing into futures where it does, in fact, continue. The fact that you are conscious now is clear evidence that you have not died... whether an alternative "you" died isn't relevant to whether you died (at least, not under the assumptions of quantum immortality.) Of course. And neither should any distasteful consequences (like excruciating death?) influence our decision on whether some idea is true or not.
Most physicists that I have talked to believe in the Many Worlds interpretation, in some incarnation. The biggest problem with this interpretation is that it suffers from a terrible name. There aren't literally "many worlds". There's just one world, in a disgusting superposition of many states.
Good point. Since there are no wavefunction collapses, nothing ever definitively happens in MWI. At least not in the sense that we usually imagine events occurring in a definite, ordered way. The most appropriate response to quantum suicide is probably to point out that, under MWI, everyone already did shoot themselves in the head - and die - and that this is in fact not mutually exclusive with the observation that nobody shot themselves in the head, and we're all here alive discussing MWI. I suspect that the reason so many physicists like MWI is that by removing the mysterious wavefunction collapse, all you're left with is an illustration that interpretations don't affect anything in nature, and so you'd best get back to doing actual science...
Good point! It's true that I don't like MWI partly because of it's consequences. This neatly sums up my opinion. Discussing QM interpretations is not fruitful for actual Physicists doing actual work, and MWI is a clean way to dismiss the subject. As Ben said, it's something that is discussed occasionally over a beer. Anyway, MWI has been described in terms of the Universe "splitting" at the quantum level, and the example I've seen given is with a photon traveling through a half-silvered mirror. When the photon travels through the mirror, the Universe "splits" into two with the electron passing through the mirror in one universe and it reflecting off the mirror in the other universe. This is easy to understand, but quantum effects are rarely so clean cut. Here is my first question: What if the mirror is 75% silvered? Are there now 4 total Universes, 3 with a reflected photon and one with a passing photon? Or are there still only 2 Universes with one being "more likely" than the other? If this is the case, by what mechanism does probability theory make the "more likely" Universe more likely to be experienced?
