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New books mount aggressive but ultimately unpersuasive defenses of multiverses

blogs.scientificamerican.com

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Re: New books mount aggressive but ultimately unpersuasive defenses of multiverses

#51

Post by [deleted] »

bawolff wrote: post #41
archgoon wrote: post #39

Earlier quoted context omitted.

Sufficiently few that it is beginning to be said by a small number of physicists that it is a point of embarrassment that the Measurement Problem is about as unresolved as when it first came up a hundred years ago. https://www.nytimes.com/2019/09/07/opinion/sunday/quantum-ph...

The nytimes article you linked has the quote: > But what is the wave function? Is it a complete and comprehensive representation of the world? Or do we need additional physical quantities to fully capture reality, as Albert Einstein and others suspected? Or does the wave function have no direct connection with reality at all, merely characterizing our personal ignorance about what we will eventually measure in our ex…

[deleted]

Re: New books mount aggressive but ultimately unpersuasive defenses of multiverses

#52

Post by teilo »

mlthoughts2018 wrote: post #50
teilo wrote: post #16

Earlier quoted context omitted.

> Multiverse QM is a settled debate. Move on. That's ridiculous. The Copenhagen Interpretation is still the prevailing view, among MANY others: https://en.wikipedia.org/wiki/Interpretations_of_quantum_mec... Further, the science is settled, so anyone who disagrees is a denier? Is that you, Mr. Carroll?

Why do you think a poll among certain people adds credulity to one or the other? Many Worlds allows purely unitary wave function evolution while explaining all known experimental and observational results with no less fidelity than any alternative. It’s solely a matter of Occam’s Razor that, until there is experimental evidence to the contrary, MWI is the solely most parsimonious available explanation. Wave function…

That's just, like, your opinion, man.

It's also a red herring. You stated that the science is settled. It is not. Not even close. "Settled" means that that there is a scientific consensus by all but a fringe, that MWI is the correct interpretation of QM. Of course, that is not the case, as should be blatantly obvious to you.

Besides which, nothing in science is ever "settled." It is always open to new interpretations when new data presents itself, or when a more persuasive theory is formulated. So on both counts your "settled" argument fails.

Furthermore, this statement is pretty bold, but let me re-write it, because it applies better to MWI than to the wave collapse function: "The Many Worlds conjecture is a purely unjustified extraneous detail that violates the scientific method to believe it without additional evidence."

The inability of the MWI to distinguish itself from the CI by any experiment, real or imagined, is the very reason why it has not gained traction.

Re: New books mount aggressive but ultimately unpersuasive defenses of multiverses

#53

Post by stevenhuang »

vstuart wrote: post #48

The many worlds interpretation (MWI) as an explanation for nonlocality ("spooky action" ...) avoids more complete interpretations that avoid locality (spacetime) altogether as fundamental properties of the universe. In other leading theories (Roger Penrose's twistors| ima Arkani-Hamed's amplituhedrons; Lee Smolin's causal relations | views; ...) spacetime emerges, and issues of locality are "irrelevant." Pushing MWI…

> I frankly found the idea that any and every quantum collapse spawned a "new world" to be absurd, regardless of the arguments

Appealing to human intuition may not be the best strategy either, as whatever the truth is need not conform to any ideas of human intuition or aesthetic.

I'd be more surprised if the answer is something we can easily make sense of.

Re: New books mount aggressive but ultimately unpersuasive defenses of multiverses

#54

Post by mlthoughts2018 »

teilo wrote: post #52
mlthoughts2018 wrote: post #50

Earlier quoted context omitted.

Why do you think a poll among certain people adds credulity to one or the other? Many Worlds allows purely unitary wave function evolution while explaining all known experimental and observational results with no less fidelity than any alternative. It’s solely a matter of Occam’s Razor that, until there is experimental evidence to the contrary, MWI is the solely most parsimonious available explanation. Wave function…

That's just, like, your opinion, man. It's also a red herring. You stated that the science is settled. It is not. Not even close. "Settled" means that that there is a scientific consensus by all but a fringe, that MWI is the correct interpretation of QM. Of course, that is not the case, as should be blatantly obvious to you. Besides which, nothing in science is ever "settled." It is always open to new interpretations…

> “ Settled" means that that there is a scientific consensus”

no, science is not related to consensus. If it were, then religion would be a matter pf physics.

Science is unique in that only theories which hold up to the evidence matter, regardless of how many or few people (or experts) believe them.

In ~1800, the science against creationism was just as settled as it is today, despite the prevalence of that religious view, even among scientific authority, at that time.

Re: New books mount aggressive but ultimately unpersuasive defenses of multiverses

#55

Post by zajio1am »

pchiusano wrote: post #46
zajio1am wrote: post #27

Earlier quoted context omitted.

> The thing missing is an explanation for why we find ourselves in a particular branch. That question does not really make sense. In every branch, there is 'you' asking about why is being in that particular branch.

I think you are making a hidden assumption. Here is a good question to tease it out: why does it make sense to ask why a coin flip came up heads but not make sense to ask why we observe one QM outcome? With the coin flip, it’s understood that the probability distribution is not reality. It’s just a way of approximating reality without having to model all the things that would explain our observations. With QM we have…

Yes, i was assuming MWI, so my point was it is not a problem itself (it does not need an explanation) in context of MWI.

Re: New books mount aggressive but ultimately unpersuasive defenses of multiverses

#56

Post by CuriouslyC »

cygx wrote: post #17

I agree that the multiverse is a bit over-hyped. However, some of the author's statements just rub me the wrong way: Science cannot resolve the existence of either God or the multiverse, making agnosticism the only sensible position. Science also can't refute me being a brain in the vat, or the universe having been created last thursday with the appearance of age. It's not only ok to commit to beliefs that cannot be…

Maybe the physicists who like to geek out on the multiverse would be less happy (after all, they're choosing to study this currently), but other people would be happier because the physicists were forced to work on something that benefitted society at large rather than a select few.

Imagine there was a group of people who liked to meditate all day, every day (preferably at the beach, with a cold beer). Would you seriously argue that society should support these people in that, rather than push them to do something else to earn their keep? Note that meditating wouldn't be illegal, so they could still do it on their own time, they'd just need to have a day job.

Re: New books mount aggressive but ultimately unpersuasive defenses of multiverses

#57

Post by CuriouslyC »

mlthoughts2018 wrote: post #6

> “ The universe supposedly splits, or branches, whenever one quantum particle jostles against another, making their wave functions collapse.” I’m very tired of seeing pop science articles describe this so incorrectly. It’s a similar mistake as describing quantum computing as simultaneously trying a bunch of solution states “in parallel.” The multiverse theory doesn’t imply any “splitting” action and certainly no suc…

The fact that we observe decoherence is the reason that people talk about "splitting". If things were consistent (either behaving in a classical or "quantum" mannner), the idea that the universal wavefunction was in constant superposition would be much more intuitive.

Also, your assumption that there is no "collapse" is predicated on the notion that whatever wavefunction amplitude is modeling is a continuous variable, but IMO it is much more likely that it is discrete. If that thing is discrete, as the universe evolves, some states will cease to exist simply due to the fact that their measure will fall below the unit value. When the measure of all states but one fell below that unit, that would essentially be a collapse.

Re: New books mount aggressive but ultimately unpersuasive defenses of multiverses

#58

Post by tim333 »

oceanghost wrote: post #24
charlesism wrote: post #8

Shouldn’t the default position be that a multiverse exist? A multiverse is what logic suggests (starting with “a point in motion is a line” and moving up to higher dimensions)

Science is just a tool to make predictions. We cannot test the multiverse theory, which leaves it in the realm of philosophy or religion. This idea of a multiverse is some metaphysics sprinkled in with the Copenhagen interpretation that boils down to something like this: the total probability of any observed outcome summed with the probability of all possible outcomes is, of course, one. The metaphysics is this-- ass…

To me science is more than a tool to make predictions - it's a way of trying to figure out what's going on using experiment, reason and the like. Maybe there are multiple universes or not and maybe we'll be able to test it or not. Who knows, reality is what it is.

Re: New books mount aggressive but ultimately unpersuasive defenses of multiverses

#59

Post by admax88q »

fourthark wrote: post #47
maroonblazer wrote: post #43

From the final paragraph: >But I’m less entertained by multiverse theories than I once was, for a couple of reasons. First, science is in a slump, for reasons both internal and external. It is?? Does anyone know to what he's referring? From my un-scientific vantage point it seems to be thriving.

Probably stuff like, we still don’t have any new particles despite spending a lot of money smashing stuff. And string theory looks like it may have wasted a lot of people’s time with no result.

We do have new particles. The Higgs Boson was observed. Unless you don't count that because it was observed where we predicted it, but then you're just punishing scientists for being right.

Re: New books mount aggressive but ultimately unpersuasive defenses of multiverses

#60

Post by MockObject »

pchiusano wrote: post #46
zajio1am wrote: post #27

Earlier quoted context omitted.

> The thing missing is an explanation for why we find ourselves in a particular branch. That question does not really make sense. In every branch, there is 'you' asking about why is being in that particular branch.

I think you are making a hidden assumption. Here is a good question to tease it out: why does it make sense to ask why a coin flip came up heads but not make sense to ask why we observe one QM outcome? With the coin flip, it’s understood that the probability distribution is not reality. It’s just a way of approximating reality without having to model all the things that would explain our observations. With QM we have…

> why does it make sense to ask why a coin flip came up heads but not make sense to ask why we observe one QM outcome?

But you had just explained why:

> With quantum measurement, there is no such explanation available, even in principle.

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