Does Everettian QM imply solipsism according to Travis Norsen and Sean Carroll?

[EclogiteFacies]

TL;DR Summary

Everettian FAPP solipsism as illustrated by Norsen implies some pretty strange stuff. But doesn't seem to deny the existence of other observers. Can someone more literate summarise this for me?

Travis Norsen in his paper Quantum Solipsism and Non-Locality seems to believe that Everettian QM implies some sort of solipsism. He falls it FAPP (for all present purposes) solipsism. (I must say that as a geologist this goes over my head a bit!)
However I have recently read Sean Carrolls Something Deeply Hidden and did not get the impression that this is at all what Many Worlds interpretation even slightly implies.
Many Worlds appeared to me as a strictly realist interpretation where different versions of ourselves become part of different branches of the wave function following a quantum measurement.
Not at all that other observers don't exist.
However I also don't think this is what Norsen implies. As he says, solipsism is ridiculous. The paper is here for reference

http://www.ijqf.org/wps/wp-content/uploads/2014/12/Norsen-Bell-paper.pdf

Any advice would be appreciated.

 

[Demystifier]

FAPP (for all practical purposes) solipsism is very different from true solipsism. Norsen argues that, if the many-worlds interpretation is right, then the actual reality is very different from how the world appears in our minds. (Essentially, this is because we perceive the world as 3-dimensional, while the actual world, according to the many-worlds interpretation, is infinite-dimensional.) But once we accept that the actual world can be very different from how we perceive it, then it is very much like the Matrix movie or brain in a vat scenario. And for practical purpose, Norsen argues, it's not much different from solipsism. If it's plausible that the 3-dimensional world is just a construct of my mind, then it may be equally plausible that the existence of other conscious beings is a construct of my mind too.

 

[EclogiteFacies]

FAPP (for all practical purposes) solipsism is very different from true solipsism. Norsen argues that, if the many-worlds interpretation is right, then the actual reality is very different from how the world appears in our minds. (Essentially, this is because we perceive the world as 3-dimensional, while the actual world, according to the many-worlds interpretation, is infinite-dimensional.) But once we accept that the actual world can be very different from how we perceive it, then it is very much like the Matrix movie or brain in a vat scenario. And for practical purpose, Norsen argues, it's not much different from solipsism. If it's plausible that the 3-dimensional world is just a construct of my mind, then it may be equally plausible that the existence of other conscious beings is a construct of my mind too.

I very much agree with your summary. I have since read the paper a second time.
However, I feel like he is not at all implying that other conscious beings are non-existent. I think he argues that we are all perceive the world in an equal way, equally as illusionary as the next.
So, in a way it's not really solipsism in the sense other conscious observers don't exist. But instead in the sense the true nature of the universe is unclear.
Anyway, I'm sure many Many Worlds supporters would disagree with his claims.

 

[EclogiteFacies]

I also feel like the point of the paper wasn't to imply the world is solipsistic. But instead point out issues in certain quantum mechanical frameworks...

 

[Demystifier]

I also feel like the point of the paper wasn't to imply the world is solipsistic. But instead point out issues in certain quantum mechanical frameworks...

Yes, I definitely agree on that.

 

[EclogiteFacies]

Yes, I definitely agree on that.

Any comments on my other comment?
Also, do you support the MWI?

Thanks for replying btw.

 

[Demystifier]

Any comments on my other comment?

Not really, except that I essentially agree.

Also, do you support the MWI?

Not really. You can see what I wrote about MWI (and other interpretations) in
https://arxiv.org/abs/1703.08341

 

[EclogiteFacies]

Not really, except that I essentially agree.Not really. You can see what I wrote about MWI (and other interpretations) in
https://arxiv.org/abs/1703.08341

I'll give it a read!
Thank you again for your comments!

 

[EclogiteFacies]

Not really, except that I essentially agree.Not really. You can see what I wrote about MWI (and other interpretations) in
https://arxiv.org/abs/1703.08341

I saw your paper on Solipsistic Hidden Variables. Sorry to be a bother, but do you really believe this interpretation could be true?
I believe from your paper that you do not believe it to be true, as it's a huge stretch metaphysically. You instead believe that this is is theoretically a possibility if one is to demand locality...
It's not really a bought into ideology.

Which interpretation do you personally ascribe to?

Thank you again

 

[Demystifier]

I saw your paper on Solipsistic Hidden Variables. Sorry to be a bother, but do you really believe this interpretation could be true?

Of course not.

I believe from your paper that you do not believe it to be true, as it's a huge stretch metaphysically. You instead believe that this is is theoretically a possibility if one is to demand locality...

Yes, sort of.

Which interpretation do you personally ascribe too?

IBM (Instrumental Bohmian Mechanics), see the link in my signature below.

 

[EclogiteFacies]

Lol, well. I assume if you did truly believe it, why would you even bother replying lol!

I think it is necessary to point out these sorts of ideas in QM regardless of how strange they may appear.
Surely it's better to understand each interpretation and why they aren't viable, than it is to just ignore them entirely because you don't like the metaphysics.

Thank you again for your input, really interesting stuff
I'll give your paper a read.

Any further comments would be interesting!

 

[Demystifier]

Lol, well. I assume if you did truly believe it, why would you even bother replying lol!

I think it is necessary to point out these sorts of ideas in QM regardless of how strange they may appear.
Surely it's better to understand each interpretation and why they aren't viable, than it is to just ignore them entirely because you don't like the metaphysics.

Yes, exactly!

Thank you again for your input, really interesting stuff
I'll give your paper a read.

 

[PeterDonis]

once we accept that the actual world can be very different from how we perceive it, then it is very much like the Matrix movie or brain in a vat scenario. And for practical purpose, Norsen argues, it's not much different from solipsism. If it's plausible that the 3-dimensional world is just a construct of my mind, then it may be equally plausible that the existence of other conscious beings is a construct of my mind too.

While this is true, I don't think it's the primary point Norsen is making. I think the primary point Norsen is making is that all of these viewpoints undermine themselves: they come up with a model of what "reality" is like based on information taken from experience, but the model says that information taken from experience is not reliable as a guide to what "reality" is like.

 

[EclogiteFacies]

While this is true, I don't think it's the primary point Norsen is making. I think the primary point Norsen is making is that all of these viewpoints undermine themselves: they come up with a model of what "reality" is like based on information taken from experience, but the model says that information taken from experience is not reliable as a guide to what "reality" is like.

Would many world supporters disagree with this?

 

[PeterDonis]

Would many world supporters disagree with this?

Probably not, but that in itself would not make the argument invalid. An MWI supporter would need to actually rebut the substance of the argument. I don't know whether any MWI supporter has attempted to do that.

 

[EclogiteFacies]

Interesting thank you!
What interpretation do you prefer most?

 

[PeterDonis]

What interpretation do you prefer most?

If I had to pick one, it would probably be the statistical/ensemble interpretation. Generally, however, I prefer not to commit to any interpretation, but just to stick to the basic math of QM.

 

[Demystifier]

they come up with a model of what "reality" is like based on information taken from experience, but the model says that information taken from experience is not reliable as a guide to what "reality" is like.

 

[AlexCaledin]

Well, let's start from MWI. Anyway, we are experiencing one single world - so, we do somehow observe some sort of collapse ( = the branch choice) which is reducing the whole spacetime universe quantum state forming everything - including our brains with our science - so any hypothesis about how exactly that collapse operates is unprovable, MWI just being one of fantasies about that.

 

[PeterDonis]

Anyway, we are experiencing one single world - so, we do somehow observe some sort of collapse which is reducing the whole spacetime universe quantum state

This is precisely the inference that the MWI rejects. The problem is that simple word "we": according to the MWI, the "we" who experiences one single world before a quantum measurement is not the same as the "we" who experiences one single world after the measurement.