Alternate Universe

[Bill]

From Wikipedia:

The many-worlds theory proposes instead that every time one state, or
outcome, is observed, there is another "world" in which a different quantum
outcome becomes reality. This is a branching arrangement, in which instant
by instant, our perceived universe branches into near-infinite alternatives.
Those alternate universes are completely separate and unable to intersect,
so while there may be uncountable versions of you living a life that's
slightly — or wildly — different from your life in this world, you'd never
know it.

New universes pop into existence all the time so the universal constants of
one universe may (probably do) change making one universe inhospitable to
all the others. This has the happy affect of making everything possible,
somewhere. It may be that nothing is impossible.

Bill

[Bill]

I wrote this using the server at news.aioe.org and read it at
reader.eternal-september.org so the electrons bounced all over the place
with no loss of information. This is not the same universe Newton used to
measure the force of gravity so, what does it all mean?

Bill

[Öö Tiib]

I don't understand what are you talking about. Sir Isaac Newton most likely
existed and did his work in our universe. It was over 3 centuries ago so I
wasn't there but I see no reason to doubt it.

[RonO]

Actually this means that the laws of nature are not fine tuned, but have
pretty much been the same as they always have. If the laws of nature
could be different in the different universes we would have evaporated
long ago. The only reason we are still here is that all the infinite
new universes that have always spawned have maintained the same laws of
nature. Those that did not would see things start to go wrong. If the
change was large enough that universe would just fall apart.

Ron Okimoto

[jillery]

On Fri, 2 Dec 2022 15:55:43 -0800 (PST), Öö Tiib <oot...@hot.ee>
wrote:

Don't fee bad, Freon Bill doesn't understand what he's talking about
either. There are other types of multiverse which do presume
different physical laws, but Many Worlds is not one of them. So he
has no good reason to claim those other Many Worlds would be
inhospitable, at least no more so than this world is.

--
You're entitled to your own opinions.
You're not entitled to your own facts.

[J. J. Lodder]

FYI:
You are confusing the many-worlds interpretation of quantum mechanics
and the multiverses of string theory.

These really are quite different things,

Jan

[Bill]

Only in that the are different theories. Since each claims scientific
credibility then they each are about some aspect of nature. Can all these
theories be true at the same time? Can they all be false?

Bill

[erik simpson]

Multiverse "theories" are still in the speculative stage; direct evidence for
their existence is still lacking. Despite that, some have been worked out
well beyond the wild idea stage. The "many worlds" of QM is very different
from cosmological multiverse, as the many worlds share the same physics,
while at least some the cosmological theories are unconstrained. My impression
is that many worlds isn't as popular in QM circles, but I'm considerable removed
from those circles, and I could be wrong. The lack of constraint is a problem that
string theory has had all along. Given the nature of physics, no theories are the last
word on anything. Some don't even have a good first word.

[israel socratus]

On Friday, December 2, 2022 at 11:25:08 PM UTC+2, Bill wrote:
> From Wikipedia:
> The many-worlds theory proposes instead that every time one state,
or outcome, is observed, there is another "world" in which a different
quantum outcome becomes reality.

> Bill
-----
When an observable quantum (dualistic) particle (in our material world)
decays/collapses, It immediately appears in another world - in the Cosmic
Vacuum, in the form of so-called "virtual particles", which can reappear
as a real, observable particle (due to entropy , quantum fluctuation
and the so-called "renormalization method")
--------

[jillery]

To add to your comments above:

<https://en.wikipedia.org/wiki/Multiverse#Types>

Many Worlds multiverse is an alternative to the Copenhagen
Interpretation of waveform collapse. This hypothesis doesn't presume
different physical constants in different universes.

In contrast, there's the multiverse from eternal inflation, which does
allow the possibility of different physical constants.

Then there's the multiverse of the observable universe, a sphere
around every point that identifies how far out any point can observe
the universe. By definition, any region outside that sphere can't be
observed, but we know with certainty those regions exist.

The main point is, none of them are motivated as a means to avoid
fine-tuning.

[israel socratus]

On Saturday, December 10, 2022 at 6:00:16 AM UTC+2, jillery wrote:
------
Many Worlds multiverse is interaction between the World of the Cosmic Vacuum and
all kinds of different structures of Material worlds (galaxies, stars, planets . . . etc.)

[jillery]

On Fri, 9 Dec 2022 22:47:33 -0800 (PST), israel socratus
<socrat...@gmail.com> wrote:

>On Saturday, December 10, 2022 at 6:00:16 AM UTC+2, jillery wrote:
>------

Nope. Prove me wrong.

>Many Worlds multiverse is interaction between the World of the Cosmic Vacuum and
>all kinds of different structures of Material worlds (galaxies, stars, planets . . . etc.)

<https://en.wikipedia.org/wiki/Many-worlds_interpretation>
************************************************
The many-worlds interpretation (MWI) is an interpretation of quantum
mechanics that asserts that the universal wavefunction is objectively
real, and that there is no wave function collapse. This implies that
all possible outcomes of quantum measurements are physically realized
in some "world" or universe. In contrast to some other
interpretations, such as the Copenhagen interpretation, the evolution
of reality as a whole in MWI is rigidly deterministic and local.
Many-worlds is also called the relative state formulation or the
Everett interpretation, after physicist Hugh Everett, who first
proposed it in 1957. Bryce DeWitt popularized the formulation and
named it many-worlds in the 1970s.
***********************************************

[J. J. Lodder]

No, of course you are not wrong, because you cannot possibly be.
"Many-Worlds" is -not- a physical theory.
It is an -interpretation- of standard quantum mechanics.
It does not differ in any physical prediction
from any other interpretation of QM.
You can take it or leave, as you please.
It is no longer fashionable,
because early hopes that it might somehow evolve
into a real physical theory have evaporated.

> The lack of constraint is a problem that string theory has had all along.
> Given the nature of physics, no theories are the last word on anything.
> Some don't even have a good first word.

Right, and that includes string theory, imho of course.
It applies only to self-created problems,
and doesn't deliver any goods,

Jan

[jillery]

Everything that you say about MWI is as applicable to all other QM
interpretations, including the original Copenhagen Interpretation.

[erik simpson]

If I were still active, I would be a subscriber to the "shut up and calculate"
school. Less opportunity to make a fool of yourself. The success of many
quantum calculations is more than sufficient to reassure that we're on the
right path, at least to somewhere. Surprises will show up, and many of our
concerns with "what it really means" may evaporate, probably to be replaced
by other (similar) questions.

[Burkhard]

Here a recent take by Sabine Hossenfelder, interesting also b/c she
claims some physicists are using quasi-religious modes of thinking
(which she considers to be a bad thing) in the way the jump from the
beauty of an abstract construct to the claim it must represent something
in reality

https://www.theguardian.com/science/2022/nov/26/physicist-sabine-hossenfelder-there-are-quite-a-few-areas-where-physics-blurs-into-religion-multiverse

[Lawyer Daggett]

And if I said that was beautiful ...

[Burkhard]

Then you cause the immediate end of all of existence due to an
irresolvable paradox, so please don't

[jillery]

On Sat, 10 Dec 2022 09:00:05 -0800 (PST), erik simpson

>If I were still active, I would be a subscriber to the "shut up and calculate"
>school. Less opportunity to make a fool of yourself. The success of many
>quantum calculations is more than sufficient to reassure that we're on the
>right path, at least to somewhere. Surprises will show up, and many of our
>concerns with "what it really means" may evaporate, probably to be replaced
>by other (similar) questions.

Then you should love MWI, which applies the Schrodinger Equation to
the entire universe, not just those parts which have not yet been
observed/measured.

<https://www.youtube.com/watch?v=t_xqNDII--Q>


And since you mention it, I suppose there's nothing wrong with "shutup
and calculate". Ptolemy might have said the same to Copernicus, and
Cuvier might have said the same to Darwin.

The thing is, that's relying on a rote model, not an explanatory
theory. Where would astronomy be if it settled for calculating stellar
positions? Or biology if it settled for organizing species?

[jillery]

On Sat, 10 Dec 2022 18:33:23 +0000, Burkhard <b.sc...@ed.ac.uk>
wrote:

An irony to your comment is that many physicists refer to the beauty
of the math to justify "shutup and calculate".

[Burkhard]

On reflection, please do...

[Lawyer Daggett]

That's just the World Cup talking.

[erik simpson]

Math is a human language of immense value when describing our ideas
about how physics works. It isn't phyics; physics is how things really work.
I think that's the complaint that Hossenfelder expresses. Math looks like it
predicts things, but I think "suggests" is a better word.

[Burkhard]

Ah, but I've been rooting for the auld alliance of course :o)

[jillery]

On Sat, 10 Dec 2022 14:11:21 -0800 (PST), erik simpson

>> >> If I were still active, I would be a subscriber to the "shut up and calculate"
>> >> school. Less opportunity to make a fool of yourself. The success of many
>> >> quantum calculations is more than sufficient to reassure that we're on the
>> >> right path, at least to somewhere. Surprises will show up, and many of our
>> >> concerns with "what it really means" may evaporate, probably to be replaced
>> >> by other (similar) questions.
>> >>
>> >Here a recent take by Sabine Hossenfelder, interesting also b/c she
>> >claims some physicists are using quasi-religious modes of thinking
>> >(which she considers to be a bad thing) in the way the jump from the
>> >beauty of an abstract construct to the claim it must represent something
>> >in reality
>> >
>> >https://www.theguardian.com/science/2022/nov/26/physicist-sabine-hossenfelder-there-are-quite-a-few-areas-where-physics-blurs-into-religion-multiverse
>> An irony to your comment is that many physicists refer to the beauty
>> of the math to justify "shutup and calculate".
>

>Math is a human language of immense value when describing our ideas
>about how physics works. It isn't phyics; physics is how things really work.
>I think that's the complaint that Hossenfelder expresses. Math looks like it
>predicts things, but I think "suggests" is a better word.

In the cited article, Hossenfelder claims multiverse are a waste of
time and ascientific, and also says she just wants to know what the
math is good for. That all but admits she's in the "shutup and
calculate" camp. Sean Carroll's contrasting POV is that camp has
given up explaining anything. That's the trouble with settling for a
model instead of a theory.

An irony here is multiverse are conclusions derived from the very
mathematics that camp declares to be "more than sufficient", except
when the math leads to conclusions they don't like.

[israel socratus]

---------
‘’Since the mathematical physicists have taken over, theoretical physics has gone to pot.
The bizarre concepts generated out of the overuse and misinterpretation of mathematics
would be funny if it were not for the tragedy of the waste in time, manpower, money,
and the resulting misdirection.’’
/Richard Feynman/

[Martin Harran]

On Sat, 10 Dec 2022 18:33:23 +0000, Burkhard <b.sc...@ed.ac.uk>
wrote:

Hossenfelder has a great talent for explaining things and has produced
some excellent YouTube videos but this is the problem I find with her
- her insistence that this is all about mathematical calculations, not
anything real. It's hard to see the usefulness of a model if it is not
related to reality.

----------------------------

P.S. In the above article, she says " ... I just couldn't get myself
to believe that God exists" then later responds to a question with "Oh
Jesus." I always find it amusing when that happens :)

[broger...@gmail.com]

I don't get an insistence that "this is all about mathematical calculations, not anything real," from what she says. Not at all. In fact I think her whole project with the foundations of physics is looking for models that are models of something real. What specifically are you thinking of?

[erik simpson]

I think you misunderstand her point. Math is essential (maybe as a mental crutch) to
do physics at all. We just need to keep in mind that the math is a descriptive tool, not
the real thing itself.

[Martin Harran]

Back in July, I was asking about Robert Lanza's ideas on biocentrism.
You said that he was misrepresenting the Copenhagen interpretation and
suggested I look at Hossenfelder's videos, giving links to two of
them.

The second one was https://www.youtube.com/watch?v=j6Mw3_tOcNI

Starting at 1:18 in that video:

<quote>

And that's what is called a "superposition". It's a sum with arbitrary
pre-factors. It really sounds more mysterious than it is.

It is relevant because this means if you have two solutions of the
Schroedinger equation that reasonably correspond to realistic
situations, then any superposition of them also reasonably corresponds
to a realistic situation.

This is where the idea comes from that if the cat can be dead and the
cat can be alive, then the cat can also be in a superposition of dead
and alive. Which some people interpret to means, it's neither dead nor
alive but somehow, both, until you measure it.

Personally, I am an instrumentalist and I don't assign any particular
meaning to such a superposition. It's merely a mathematical tool to
make a prediction for a measurement outcome.

</quote>

OK, I might have overstated things by that this is *all* about
mathematical calculations (I was using the word loosely) but it seems
to underly quite a bit of here thinking according to that Guardian
article.

[jillery]

On Sun, 11 Dec 2022 08:39:38 -0800 (PST), erik simpson
<eastsi...@gmail.com> wrote:

>I think you misunderstand her point. Math is essential (maybe as a mental crutch) to
>do physics at all. We just need to keep in mind that the math is a descriptive tool, not
>the real thing itself.

So how do you reconcile that with "shutup and calculate"?

[broger...@gmail.com]

I think that her point there is much narrower than you seem to be interpreting it. She is talking specifically about quantum superpositions, and her job is basically to try to make sense of the most confusing aspects of QM. It is not at all her point that mathematical models are not related to reality. In fact, she has at least one video directly addressing the relationship between math and reality

https://www.youtube.com/watch?v=CTpp0EChDbI

As you can see from that video, she does not think all math is the same. Some math accurately describes observations; other math does not. One of her critiques of modern physics is that it has become obsessed with mathematical beauty and elegance, and lost touch with the need to ground the math in observations. If you disconnect math from observations, or allow yourself lots of free parameters to play with, you can generate all sorts of lovely math that has very little contact with reality - predict new particles, new scenarios for cyclic universes, multiverses, collisions of universes on multi-dimensional membranes. Her critique is that people are wasting their time looking for beautiful math instead of looking for physical phenomena that need explanation through experiments. At least that is how I understand her.

> >> ----------------------------
> >>
> >> P.S. In the above article, she says " ... I just couldn't get myself
> >> to believe that God exists" then later responds to a question with "Oh
> >> Jesus." I always find it amusing when that happens :)

Yes, it's funny in the same way as it is to hear an Anglican say "By Jove."

[erik simpson]

What's to reconcile? We have theories that a well-suppported by experiment. Calculations
based on them are often as accurate as or more than celestial mechanics. Calculations
based on more speculative theories (sometime nearly pure speculation) give results that
need more critical evaluation.

[jillery]

On Sat, 10 Dec 2022 21:49:21 -0500, jillery <69jp...@gmail.com>

The following is a link to a 17-minute Youtube video of Hossenfelder
explaining why she thinks mutiverse "is a waste of time":

<https://www.youtube.com/watch?v=QHa1vbwVaNU>
*****************************************
@8:01
The issue with all those different multiverses is that they postulate
the existence of something you can’t observe, which is those other
universes. Not only can you not see them, you can’t interact with them
in any way. They are entirely disconnected from ours. There is no
possible observation that you could make to infer their presence, not
even in principle. For this reason, postulating that the other
universes exist is unnecessary to explain what we do observe, and
therefore something that a scientist shouldn’t do. Making an
unnecessary assumption is logically equivalent to postulating the
existence of an unobservable god, or a flying spaghetti monster, or
an omniscient dwarf who lives in your wardrobe. Fine if you do it in
private, not so fine if you publish papers about it.
*******************************************

The following link is to a 20-minute Youtube video of Sean Carroll and
Lex Fridman having a rational discussion about MWI:

<https://www.youtube.com/watch?v=kxvQ3Wyw2M4>

The following is to a Youtube video that Carroll mentioned, a World
Science Festival panel discussion with Sean Carroll, David Albert,
Sheldon Goldstein, Ruediger Schack, and moderated by Brian Greene:

<https://www.youtube.com/watch?v=GdqC2bVLesQ>

For those interested in informing themselves about this topic and
other things about how the very small informs the very large, I
recommend reading Carroll's book "Something Deeply Hidden".

I have read/listened to all of the above. This is not to say that I
grok all that I read/heard. But it does say that at least I made an
effort.

[jillery]

On Sun, 11 Dec 2022 09:41:25 -0800 (PST), erik simpson

<eastsi...@gmail.com> wrote:

>On Sunday, December 11, 2022 at 9:10:17 AM UTC-8, jillery wrote:
>> On Sun, 11 Dec 2022 08:39:38 -0800 (PST), erik simpson
>> <eastsi...@gmail.com> wrote:
>>
>> >I think you misunderstand her point. Math is essential (maybe as a mental crutch) to
>> >do physics at all. We just need to keep in mind that the math is a descriptive tool, not
>> >the real thing itself.
>> So how do you reconcile that with "shutup and calculate"?
>>

>What's to reconcile? We have theories that a well-suppported by experiment. Calculations
>based on them are often as accurate as or more than celestial mechanics. Calculations
>based on more speculative theories (sometime nearly pure speculation) give results that
>need more critical evaluation.

Since you asked, your quote summarizes the attitude you expressed
previously, that doing so "is more than sufficient to reassure that
we're on the right path." If that is so, then there's no need to
bother with "the real thing itself"; the "beautiful" math is
sufficient. ISTM these two statements contradict.

[Bill]

Math s a placeholder used to help us keep track of whatever we were thinking
about. It's the thoughts behind the math that matter, not the math itself.
Few here seem to agree.

Bill

[erik simpson]

On Sunday, December 11, 2022 at 10:15:17 AM UTC-8, Bill wrote:
...

> Math s a placeholder used to help us keep track of whatever we were thinking
> about. It's the thoughts behind the math that matter, not the math itself.
> Few here seem to agree.
>
> Bill

If I understand you correctly, and for what it's worth, I agree with you.

[erik simpson]

It depends on what you're trying to calculate. Quantum electrodynamics is solid.
Quantum chromodynamics is fairly solid. The "Standard Model" has holes. "Beautiful
math" is irrelvant if the results aren't beautiful. Math applied to things that can't be
observed (like totally disconnected multiverses) doesn't tell us anything unless we find
some way to check the results. If you still see contradiction, that's fine; I'll not argue.

[jillery]

I would say it's not the thoughts behind the math, but instead it's
the reality those thoughts and math are supposed to describe. There's
a difference.

[jillery]

On Sun, 11 Dec 2022 10:21:35 -0800 (PST), erik simpson

<eastsi...@gmail.com> wrote:

>On Sunday, December 11, 2022 at 10:10:17 AM UTC-8, jillery wrote:
>> On Sun, 11 Dec 2022 09:41:25 -0800 (PST), erik simpson
>> <eastsi...@gmail.com> wrote:
>>
>> >On Sunday, December 11, 2022 at 9:10:17 AM UTC-8, jillery wrote:
>> >> On Sun, 11 Dec 2022 08:39:38 -0800 (PST), erik simpson
>> >> <eastsi...@gmail.com> wrote:
>> >>
>> >> >I think you misunderstand her point. Math is essential (maybe as a mental crutch) to
>> >> >do physics at all. We just need to keep in mind that the math is a descriptive tool, not
>> >> >the real thing itself.
>> >> So how do you reconcile that with "shutup and calculate"?
>> >>
>> >What's to reconcile? We have theories that a well-suppported by experiment. Calculations
>> >based on them are often as accurate as or more than celestial mechanics. Calculations
>> >based on more speculative theories (sometime nearly pure speculation) give results that
>> >need more critical evaluation.
>> Since you asked, your quote summarizes the attitude you expressed
>> previously, that doing so "is more than sufficient to reassure that
>> we're on the right path." If that is so, then there's no need to
>> bother with "the real thing itself"; the "beautiful" math is
>> sufficient. ISTM these two statements contradict.
>

>It depends on what you're trying to calculate. Quantum electrodynamics is solid.
>Quantum chromodynamics is fairly solid. The "Standard Model" has holes. "Beautiful
>math" is irrelvant if the results aren't beautiful. Math applied to things that can't be
>observed (like totally disconnected multiverses) doesn't tell us anything unless we find
>some way to check the results. If you still see contradiction, that's fine; I'll not argue.

Thank you for clarifying and qualifying what you meant. I now
understand that you didn't mean to say the math is more than
sufficient to reassure, but instead you really meant that math
describes aka models, and must be mapped onto theoretical foundations
in order to explicate.

As for what can be observed, there are lots of things that have not
been observed, including almost all of the particles physicists use
math to describe. Instead, what are observed are indirect effects
inferred by *theory* to be consequences of those particles. Do you
doubt the existence of spacetime beyond the observable universe, which
is defined as the region that can't be observed and is causally
disconnected? If not, then why doubt the existence of Everettian
multiverse?

[Martin Harran]

On Sun, 11 Dec 2022 09:37:57 -0800 (PST), "broger...@gmail.com"

Whilst I have reservations about Hossenfelder's own emphasis on
mathematics, I broadly agree with her underlying argument that it is
too easy for scientists to latch onto a favourite idea based on
conceptual thinking and ignore shortcomings in its practical
application.

I think that at this point in time, we have to accept that there is
more that we don't understand about quantum mechanics than we do
understand. There are lots of ideas about possible answers to some of
the things we don't understand but they really only are ideas at this
stage as none of them can be satisfactorily tested and most of them
seem to raise as many questions as they answer.

That is not to denigrate the work that is going on and the ideas that
are being explored. Science at its heart is about exploring the
unknown and trying out ideas I happen to be currently reading
"Helgoland: The Strange and Beautiful Story of Quantum Physics" by
Carlo Rovelli. In the book, he pulls no punches regarding the
shortcomings in ideas like multiple universes, invisible variables and
many worlds. He himself favours relational quantum mechanics but
accepts that it too is conceptual and can't be satisfactorily tested.
He emphasises, however, the need to keep exploring and the need to be
open to what may initially seem like weird ideas. One passage from the
book [1] particularly caught my attention, especially in the context
of the nihilism that Freon Bill insists on promulgating:

"This [the advent of quantum theory] was an abrupt awakening from the
pleasant sleep in which we had been cradled by the illusions of
Newton's success. But it was a reawakening that connects us back to
the beating heart of scientific thinking, which is not made up of
acquired certainties: it is thinking constantly in motion, the power
of which is precisely the capacity to always question everything and
begin over again, to be fearless in subverting the order of the world
in the search for a more efficient one, only to then put a further
question mark over everything, to subvert it all over again.

Not to fear rethinking the world is the power of science: ever since
Anaximander removed the foundations on which the Earth rested,
Copernicus launched it to rotate in the sky, Einstein dissolved the
rigidity of space and of time, and Darwin demolished the separateness
of humanity . . . reality is constantly being redrawn in images that
are increasingly effective. Step by step, the fabulous strangeness and
beauty of reality is unveiled. The courage to radically reinvent the
world: this was the subtle fascination of science that first
captivated me as a rebellious adolescent."


[1] Rovelli, Carlo. Helgoland: Making Sense of the Quantum Revolution.
Penguin, 2022. (Kindle Locations 850-858). Kindle Edition.

[erik simpson]

That expansion "disconnects" regions of spacetime that we could
previously observe is a process which can't be denied without
denying the observed expansion. Other universes with more than
one time-like dimension, populated with beings beyond our comprehension
is another matter. Everett's theory explains nothing we don't otherwise
know, but one adherent explained to me long ago that the great
advantage was "philosophical" in that it removed indeterminacy from QM.
I was and continue to be unimpressed. Indeterminacy in unavoidable in
physics anyway (see double pendulum, or newtonian three-body problem),
and has nothing necessarily to do with quantum mechanics. Occam's
razor strongly suggests there is no there there.

[Ernest Major]

A distinction can be drawn between an indeterminate (undetermined)
system, in which the future evolution of a system is not completely
determined by the current state, and a deterministic chaotic system, in
which the future evolution of a system is completely determined by the
current state, but is unpredictable because of its sensitive dependence
of the current state. A double pendulum, and a generalised three-body
system, belong to the latter class. With wave-function collapse, quantum
mechanical systems fall into the former class.

But one could argue contrarily that the distinction is abstract, not
real. Double pendulums and three body systems are not in reality
isolated systems, nor can they be observed without affecting them, while
on the other hand an isolated unobserved quantum system does have a
determined future evolution.

And on a different tangent, not all philosophers would consider removing
indeterminacy a positive.

--
alias Ernest Major

[jillery]

On Mon, 12 Dec 2022 08:15:07 -0800 (PST), erik simpson

>That expansion "disconnects" regions of spacetime that we could
>previously observe is a process which can't be denied without
>denying the observed expansion.

umm... not quite. As you may know, if cosmic expansion was
decelerating as was once thought, the speed of light/causality would
eventually but necessarily catch up with and surpass cosmic expansion.
However, the latest evidence shows cosmic expansion is accelerating,
and so there is necessarily a sphere beyond which spacetime is forever
disconnected from us.

The larger point is, the above is but one example of many things which
theory says can't be observed directly but are inferred from the data.
My question still applies if I used quarks as an example. Do you
doubt the existence of quarks because they can't be observed directly?

>Other universes with more than
>one time-like dimension, populated with beings beyond our comprehension
>is another matter.

What you describe above is a prediction of some versions of
multiverse, but not MWI. As I pointed out elsethread, there are
several different kinds of multiverse:

<https://en.wikipedia.org/wiki/Multiverse#Types>

>Everett's theory explains nothing we don't otherwise
>know, but one adherent explained to me long ago that the great
>advantage was "philosophical" in that it removed indeterminacy from QM.
>I was and continue to be unimpressed. Indeterminacy in unavoidable in
>physics anyway (see double pendulum, or newtonian three-body problem),
>and has nothing necessarily to do with quantum mechanics. Occam's
>razor strongly suggests there is no there there.

Sean Carroll offers a more accurate explanation:
<https://www.youtube.com/watch?v=kxvQ3Wyw2M4>
*************************************
@3:26
What Everett really says, what his theory is, is there's a wave
function of the universe, and it obeys the Schrodinger equation all
the time. That's it. That's the full theory right there.
************************************

And since you mention Occam's Razor, Carroll says this:
************************************
@16:54
[QUESTION] Why do you find many worlds so compelling?
[CARROLL] There's two reasons actually. One is like I said, it is the
simplest, right, like the most bare-bones austere pure version of
quantum mechanics. And I am someone who is very willing to put a lot
of work into mapping the formalism onto reality. I'm less willing to
complicate the formalism itself.

But the other big reason is that there's something called modern
physics, with quantum fields and quantum gravity and holography and
space-time doing things like that. And when you take any of the other
versions of quantum theory, they bring along classical baggage. All
of the other versions of quantum mechanics prejudice or privilege some
version of classical reality, like locations in space, okay? And I
think that that's a barrier to doing better at understanding the
theory of everything and understand quantum gravity and the emergence
of space-time.

Whenever if you change your theory from, you know, here's a harmonic
oscillator, oh there's a spin, here's an electromagnetic field, in
hidden variable theories or dynamical collapse theories, you have to
start from scratch, you have to say like, well, what are the hidden
variables for this theory, or how does he collapse or whatever,
whereas many worlds is plug-and-play. you tell me the theory
and I can give you its many worlds version. So when we have a
situation like we have with gravity and space-time, where the
classical description seems to break down in a dramatic way, then I
think you should start from the most quantum theory that you have,
which is really Many Worlds.
************************************
The above says to me that Occam's Razor points to MWI as the most
parsimonious.

[erik simpson]

My physics chops are vastly short of Carroll's, but my guts (for which I have some respect)
tell me the remarks you quote are Carroll's in his capacity as Professor of Natural Philosophy,
and as such are philosophical. I am not a philosopher, and I fail to see the wonder in Many Worlds.
The "classical description" does break down, and that's the breaks. Reality bites. Many Worlds doesn't
help to calculate anything, and it doesn't make me feel better. If he, or you, or anyone else prefers it
and requires an explanation of what it all means, I don't have any problem with that, I just think it's a
lot of words (not worlds).

[Ernest Major]

On 12/12/2022 19:56, jillery wrote:
> The larger point is, the above is but one example of many things which
> theory says can't be observed directly but are inferred from the data.
> My question still applies if I used quarks as an example. Do you
> doubt the existence of quarks because they can't be observed directly?

If you use sufficiently high energy electrons you can bounce them off
objects inside nucleons. These objects (partons) are now equated with
valence quarks, sea quarks, and gluons. For an expansive definition of
direct observation this seems to me to be direct observation of quarks.
(For a sufficiently restrictive definition of direct observation reading
the temperature off a thermometer isn't a direct observation.)

--
alias Ernest Major

[Öö Tiib]

Also the things inferred that we can never interact with or use in anything
even in theory are pointless and useless for us. These may be there or
not ... it does not matter.

[jillery]

I acknowledge there are different opinions about what "direct
observation" means. A blatant example is the Creationist PRATT "Were
you there?" to challenge inferences of the past. My reply to such
objections is that even though some things can't be observed directly,
they leave evidence of their existence. Your example above, of
bouncing electrons off quarks is an example of exactly that. So to
doubt the existence of quarks is to doubt the evidence itself.

However my point doesn't rely on pedantic distinctions. Erik raised a
common objection to MWI, IIUC that the existence of those many worlds
can't be tested and for that reason should be dismissed. My
counter-objection is that those many worlds are a direct consequence
of accepting the Schrodinger Equation at face value, and can be
dismissed only by making an arbitrary and ad hoc cutoff for where and
when the Schrodinger Equation applies. ISTM those who identify
themselves as "just calculate" fellows would be the first ones to
apply the Schrodinger Equation to everything, and many worlds is a
necessary consequence of that.

[jillery]

On Mon, 12 Dec 2022 14:55:35 -0800 (PST), erik simpson

I acknowledge that MWI doesn't help to calculate anything. It's not
supposed to. Your expectation entirely misses the point, using
Carroll's words, that it helps to map the formalism of QM on to
reality aka to explain QM.

Your words are like those of the Church astrologers who dismissed
heliocentrism, and insisted on sticking with Ptolemy's equants and
epicycles, because obviously the Earth doesn't move.

[jillery]

On Mon, 12 Dec 2022 18:13:27 -0800 (PST), Öö Tiib <oot...@hot.ee>
wrote:

A counter-example: the universe before its first 280,000 years is
forever hidden from direct observation behind the Cosmic Microwave
Background. Nevertheless, based what we know of high-energy atomic
interactions and what we observe of the universe, we infer what must
have happened before, which necessarily determined what happened
after.

More to the point, to say that something can never be used is
equivalent to saying a newborn baby has no use. It's not reasonable
to presume an hypothesis has no use even before it's studied.

[erik simpson]

You are entirely missing my point. Nobody is trying to use the wavefuction of
the entire universe to calculate anything. In practical usage (there's lots of that)
MWI just isn't an issue. It's not a question of sticking with Ptolemy. This argument
is going off the track, and see little point in following it.

[Öö Tiib]

It is not true that newborn baby has no use or can not be interacted with.
It is considered valuable by all jurisdictions. I do not understand, any
analogy seems missing.

[jillery]

On Mon, 12 Dec 2022 22:22:39 -0800 (PST), erik simpson

>> >My physics chops are vastly short of Carroll's, but my guts (for which I have some respect)
>> >tell me the remarks you quote are Carroll's in his capacity as Professor of Natural Philosophy,
>> >and as such are philosophical. I am not a philosopher, and I fail to see the wonder in Many Worlds.
>> >The "classical description" does break down, and that's the breaks. Reality bites. Many Worlds doesn't
>> >help to calculate anything, and it doesn't make me feel better. If he, or you, or anyone else prefers it
>> >and requires an explanation of what it all means, I don't have any problem with that, I just think it's a
>> >lot of words (not worlds).
>> I acknowledge that MWI doesn't help to calculate anything. It's not
>> supposed to. Your expectation entirely misses the point, using
>> Carroll's words, that it helps to map the formalism of QM on to
>> reality aka to explain QM.
>>
>> Your words are like those of the Church astrologers who dismissed
>> heliocentrism, and insisted on sticking with Ptolemy's equants and
>> epicycles, because obviously the Earth doesn't move.
>

>You are entirely missing my point. Nobody is trying to use the wavefuction of
>the entire universe to calculate anything. In practical usage (there's lots of that)
>MWI just isn't an issue. It's not a question of sticking with Ptolemy. This argument
>is going off the track, and see little point in following it.

I agree this argument has gone off track, since you accuse me of
missing your point even though I acknowledged your point even while
you don't acknowledge my point. But don't feel bad; you're not the
only one, but I had hoped for better from you.

My reference to Ptolemy was a straightforward *analogy* to illustrate
your failure to address the conceptually simpler and more coherent
explanation MWI provides. Perhaps if you first dropped your focus on
calculating and then read Carroll's book? You don't have to agree
with him or me, but it would be nice if you agreed on what the
disagreement is about.

[jillery]

On Tue, 13 Dec 2022 08:38:36 -0800 (PST), Öö Tiib <oot...@hot.ee>

That's my point. It's a reference to comments made by Benjamin
Franklin and Michael Faraday to those who questioned the value of
apparently useless ideas.

>It is considered valuable by all jurisdictions. I do not understand, any
>analogy seems missing.

Read again what you wrote. To refresh your memory:

"Also the things inferred that we can never interact with or use in
anything even in theory are pointless and useless for us. These may be
there or not ... it does not matter."

Your comments throw out the baby with the bathwater.

[erik simpson]

No hostility intended, but which point did I miss? I have things to do I find more interesting
than reading Carroll's explanation of why MW is compelling. The debate about the
"meaning" or "interpretation" of QM has been ongoing since its developement, with
physicists and philosophers of great stature expressing fundamental disagreement. The
Wiki entry recounts multiple "polls" taking at various meetings, which rank some of
the contending intepretations. (As though correct physics can be determined by voting!)
As regards calculation, the "facts" are not in dispute. The "opinions" are still very various.
I am impressed by the thought that QM is essentially incomplete, since gravitation is still
stubborn, and that differing intepretations cannot be resolved as long as this situation
persists.

[Öö Tiib]

Yes, by those very theories we can never use nor interact with the
alternative universes that are there only by extending algorithms
of models that we are even uncertain if those hold about our own
universe. Models are easy enough to make, every computer game has
some model of game world in it and players then try to gain upper
hand by "cheese", by abusing its limitations and defects. Non useful
sector in some theoretical model is nothing like real baby that we
can interact with and use in various ways as baby is valued by many.

[JTEM is my hero]

Bill wrote:

> New universes pop into existence all the time

No. Impossible. Time only exists BECAUSE we are inside of this universe.

Spacetime.

Step outside of our universe and it doesn't even exist! There would be no
space for it to occupy, no moment in time for it to appear within...

It's all quite impossible, and true.




-- --

https://jtem.tumblr.com/post/703468006592905216

[jillery]

On Tue, 13 Dec 2022 14:48:42 -0800 (PST), erik simpson
<eastsi...@gmail.com> wrote:

<snip uncommented text>

>No hostility intended,


Back atcha, and I inferred no hostility.

>but which point did I miss? I have things to do I find more interesting
>than reading Carroll's explanation of why MW is compelling.

That's good enough for me. Thank you for sharing your opinions with
me.

>The debate about the
>"meaning" or "interpretation" of QM has been ongoing since its developement, with
>physicists and philosophers of great stature expressing fundamental disagreement. The
>Wiki entry recounts multiple "polls" taking at various meetings, which rank some of
>the contending intepretations. (As though correct physics can be determined by voting!)
>As regards calculation, the "facts" are not in dispute. The "opinions" are still very various.
>I am impressed by the thought that QM is essentially incomplete, since gravitation is still
>stubborn, and that differing intepretations cannot be resolved as long as this situation
>persists.

[jillery]

On Tue, 13 Dec 2022 16:59:12 -0800 (PST), Öö Tiib <oot...@hot.ee>

To be accurate, the theories are very interact-able. The
non-interacting parts are *predictions* from those theories. There's
a difference.

>Models are easy enough to make, every computer game has
>some model of game world in it and players then try to gain upper
>hand by "cheese", by abusing its limitations and defects. Non useful
>sector in some theoretical model is nothing like real baby that we
>can interact with and use in various ways as baby is valued by many.

Just as newborns don't show what they will accomplish as adults, so
too new ideas don't show what discoveries they will inspire as they
develop. None of the founders of QM predicted what came from their
new theories less than fifty years later.

[erik simpson]

The best hypotheses or theories raise more and better questions than they answer.

[Öö Tiib]

That is correct as questions are always better than answers ... questions
are warning where we are in darkness. Knowing what we don't know is
more important than what we know. We do not need a model for to have
questions.

People have proven to be capable to be inspired by whatever they notice
be it falling of an apple or manifestation of a programming defect in
software they use. People who only get inspiration from models are
likely rather rare.

Number of mathematical models that can fit with some aspect of our
reality is likely limitless OTOH theory of everything might be impossible.
So all the proposed models may be just what fit by coincidence while
the search itself may be futile. Various non-interacting woo that has
only base in those questionable models should not be taken as reality
but as potentially wrong answer from extrapolating model that just
fits by coincidence.

Simpler formulas are more energy- and time-efficient to use, and good
enough for practical purpose. Such practical applied-physics
usefulness for particular purpose seems often being underrated.