- #176
stefanbanev
- 50
- 1
Fyzix said:Check.
Actually it is a checkmate (joke). No need to reply; I really respect your beliefs and see no reasons to argue with you. I wish you all the best... Stefan
Fyzix said:Check.
Which ones would that be? I just rescanned the entire thread and I can see only two links.Fyzix said:...As I have given you sources you can check...
This strong statement requires very strong proof. Please provide.Fyzix said:The "pure MWI" is wrong and infact CAN'T work.
Sigh...Delta Kilo said:Which ones would that be? I just rescanned the entire thread and I can see only two links.
One arguing that QM is non-local (duh!) and another is just random blog musings with no physical content.
This strong statement requires very strong proof. Please provide.
And I don't get why people are so obsessed with Born rule in MWI. It is so obviously correct It's part of the math of QM, it works equally well in all interpretations, it has been proven to be the only sensible measure that works.
So what? The keyword here is "local", not MWI.Fyzix said:The paper was about trying to make MWI local in Heisenberg picture, which failed...
Yes you did and no it does not.You have quoted a review that tells us that there are different opinions on the topic (duh! who would have thought!) and which in turn refers to Maudlin's paper which - have you actually read it? - is another kind of review (duh!). While reviews like this one do bring forth interesting points they are not meant to argue them conclusively. You are supposed to refer to the sources.I also quoted a long segment which brings up a lot of technical criticism of MWI, in it Amit Hagar referes to Tim Maudlin's paper "can the world be only wavefunction?" which you can google for your self...
Negative. No theory can ever be proven right, but any theory can be proven wrong. You said it's wrong, you prove it.MWI is the claim, you are the claimant, burden of proof lies on your shoulders.
Thanks, I'll check them out in due course...Want some sources?
The question is not whether the Born rule can be incorporated into MWI. Of course it can, in many ways. The question is whether incorporation of the Born rule ruins the initial beauty and simplicity of MWI. The answer is that it does! Perhaps not more than in other interpretations, but not less either. So if MWI with the Born rule incorporated is no simpler or more beautiful than other interpretations, then why one should prefer it over other interpretations? I'm sure one can find many reasons to still prefer it, and that is fine, but the point is that the initial STRONGEST argument for preferring MWI is now lost. If there was no such a loss, then MWI could easily dominate on the world-interpretation map, and that's why people are so obsessed with the Born rule, in both MWI and anti-MWI camps.Delta Kilo said:And I don't get why people are so obsessed with Born rule in MWI. It is so obviously correct It's part of the math of QM, it works equally well in all interpretations, it has been proven to be the only sensible measure that works. It is intuitively well understood (in thermodynamics sense as a ratio of the number of microstates leading to different macrostates). Yes, counting those microstates is a pain because it all comes from the measurement and measurement is a complicated multi-stage process, but the progress has been made in this direction. Actually this problem (going from micro to macro) applies equally to all interpretations, at least those that try to study the process of measurement rather just postulate it as in Copenhagen.
You're not expressing skepticism of MWI -- you're denying MWI. A denial is a claim which has a burden of proof.Fyzix said:It's not up to the skeptic.
MWI doesn't need to add postulates -- anything "core" MWI postulates were already there in ordinary quantum mechanics.Like Demystifier just said, SURE you can introduce ADDITIONAL POSTULATES to get Born Rule
Which I've provided in sources...Hurkyl said:You're not expressing skepticism of MWI -- you're denying MWI. A denial is a claim which has a burden of proof.
MWI doesn't need to add postulates -- anything "core" MWI postulates were already there in ordinary quantum mechanics.
Besides, I've always found it baffling that people would criticize any interpretation for assuming "the probabilities computed by the mathematics match the probabilities observed by experiment".
Could you please elaborate on that? How does it ruin the beauty?Demystifier said:The question is whether incorporation of the Born rule ruins the initial beauty and simplicity of MWI. The answer is that it does!
IllyaKuryakin said:I've never been able to accept the concept that the entire universe splits in two every time a leaf falls to the ground face up or face down.
This picture is misleading and that's why I don't like terms "branching" and "splitting". Instead, picture the multiverse as a turbulent flow. Close trajectories represent similar worlds. A single macroscopic state is represented by a compact parcel of gas or water where differences between trajectories are so small that they are unobservable on macroscopic level. As the parcel goes with the flow it gets split into smaller parcels which go different ways, and again and again. If the observer had perfect memory of past events then the size of it parcel (or the proportion of the flow cross-section) would shrink every time the observer learns new fact, in the limit shrinking into a single point which represent the exact configuration of the world with no fuzziness at all. However, real observers are not perfect and tend to forget things. Once a piece of information is forgotten, the corresponding "worlds"/"branches" join back together. However from the global point of view its just a flow of water under the bridge.IllyaKuryakin said:I've never been able to accept the concept that the entire universe splits in two every time a leaf falls to the ground face up or face down. Even if the math can be made to work, the concept is silly. Considering the number of particles that have made quantum choices over the history of our universe, it would take a number of universes much greater than the number of particles in our universe, and of course, every time a leaf falls to the ground in one of those, it splits in two as well, ad infinitum.
But this is exactly the issue! Hilbert space is just too darn big! You get all these degrees of freedom out of the box whether you like it or not. Just check how much memory you need to simulate 32 bits. Now do that for 32 qubits. Feel the difference? What do you do with all these numbers, where do you stick them all? (officers! silence!).Occams razor slices this to ribbons. ... Surely if you grant infinite degrees of freedom, just about anything can work out.
Fyzix said:I will take a look at the paper later today.
I've actually discussed MWI with the author through mail just some weeks ago.
He objects to MWI due to the probability problem and the fact that there is no way to say where a world starts/ends, which is really problematic.
However I'm not sure if his Many minds interpretation is the same as others, usually they require dualism of the mind.
Which I personally reject.
There is some brief information of it on wikipedia, if you google his name + many minds he also got a FAQ
The author considers several attempts at deriving Born rule in MWI by counting branches. The branching is taken as granted, no attempt is made to look at the branching process in details. No wonder it does not work. As I said the probabilities have to come out as a ratio of microstates per indistinguishable macrostates during conversion from quantum to classical. The ppaper is nowhere near that.Fyzix said:Adrian Kent
http://arxiv.org/PS_cache/arxiv/pdf/0905/0905.0624v2.pdf
Same as above. I may like MWI and at the same time I don't have to like decision-theoretic approach.Fyzix said:
Fyzix said:Meir Hemmo
http://edelstein.huji.ac.il/staff/pi...rs/Paper45.pdf
Cannot argue with that. A sensible measure of branch "thickness" is required. But that by itself does not disprove MWI.The problem is to derive Born’s rule from the many worlds theory without assuming directly or indirectly a notion of typicality or a measure over branches.
Our aim is to show that this is impossible.
Fyzix said:Nono, ofcourse I don't think the experimentalist will see both.
he splits just like whole world including the experiment.
However,
Pre-experiment you got:
1 Experimenter
A experiment with 2 possible outcomes
After the experiment
You got 2 experimenters each observing one of the 2 outcomes.
They repeat the experiment and this occurs again.
However unless MWI ASSUMES that there is something very special about consciousness that makes the universe somehow put the observers in the universe which would then correspond to the correct probability, they will see 50/50.
It's that simple.
Just draw it on a piece of paper and you will understand exactly what I mean (this thought experiment is Putnam's not mine originally).
Delta Kilo said:The author considers several attempts at deriving Born rule in MWI by counting branches. The branching is taken as granted, no attempt is made to look at the branching process in details. No wonder it does not work. As I said the probabilities have to come out as a ratio of microstates per indistinguishable macrostates during conversion from quantum to classical. The ppaper is nowhere near that.
Same as above. I may like MWI and at the same time I don't have to like decision-theoretic approach.
ExcessRed said:I apologize in advance if this has already been said. I only read the first page of this (kind of lengthy) thread, and felt the need to comment on this:
90% chance that a blue light occurs, 10% chance that a red light occurs.
Unless you know ahead of time which experimenter to choose from the theoretically infinite number of realities, there is a good chance (in our case, 90% x 90% = 81%) you'd randomly grab two blue-lighters - we can't just choose two at random.
In contrast, if you somehow knew ahead of time that the two experimenters you choose are going to express different results, then the argument is about as relevant as saying... look in a bag of marbles (90% blue, 10% red), remove one marble of each color. From that new set of two, randomly choose one marble and you would have a 50% chance of picking blue.
In essence... wouldn't a single event with a precisely 90% chance of success result in 10 branched realities - 9 successes and 1 failure - thus preserving the global probability?
Fyzix said:No and that's the whole point.
At each single event, the universe (if we look at it from MWI) would branch into 2 realities.
Delta Kilo said:As I said the probabilities have to come out as a ratio of microstates per indistinguishable macrostates during conversion from quantum to classical.
Taking the the decoherence-based philosophy that we should accept the statistical mixture as being reality rather than assuming collapse, the math tells us this is a weighted mixture of two states, with the weights being 90% and 10%.ExcessRed said:In essence... wouldn't a single event with a precisely 90% chance of success result in 10 branched realities - 9 successes and 1 failure - thus preserving the global probability?
If MWI is wrong, it means one of:Lost in Space said:If the MWI theory is wrong, does this mean that consciousness does collapse wave functions?
Hurkyl said:If MWI is wrong, it means one of:
- Some aspect of quantum mechanics is wrong
- Experimentally observed statistics in subsystems are not the result of unitary evolution in larger systems
- There are other components to physical state beyond the wave-function which contribute to observations
- Some other mode of failure I didn't think of
Of course not; there is also the hypothesis that the wavefunction only evolves according to Schrödinger's equation.*, as opposed to the combination of Schrödinger's equation and collapse.Fyzix said:Even wavefunction taken as all there is doesn't yield MWI, so, yeah...
stefanbanev said:"Quantum universe" remains in its superposition state and it is not the universe you perceive as such.
Lost in Space said:I just wonder if those who consider MWI to be wrong and that consciousness plays an integral part in determining a result, whether a belief or expectational bias on behalf of an observer can also have a bearing on the probabilistic outcome of a collapse in wave function?
Hurkyl said:If MWI is wrong, it means one of:
- Some aspect of quantum mechanics is wrong
- Experimentally observed statistics in subsystems are not the result of unitary evolution in larger systems
- There are other components to physical state beyond the wave-function which contribute to observations
- Some other mode of failure I didn't think of
The difference between physical state collapsing to a single outcome versus remaining a statistical mixture is not a physical difference -- no observation can distinguish between the two possibilities.
Consciousness has pretty much nothing to do with any of the above. Anything that talks about consciousness is a separate thing layered on top of the basics.
Fyzix said:Very very few of those who reject mwi (majority of physicists) believe in such nonsense that consciousness has ANYTHING to do with anything.
You mean as compared to other interpretations? I don't think the question is meaningful.Varon said:Hurkyl, from 1 to 10, how true do you think is MWI? Is it 10? or 5?
Varon said:Hurkyl, from 1 to 10, how true do you think is MWI? Is it 10? or 5?