It's not science. But it's speculating or philosophizing about scientific results.

Is the multiverse science fiction only? — TiredThinker

She doesn't ever say its fiction, just not science, which is probably why if you take a university course in quantum mechanics, they might spend at best one lecture on the various interpretations (philosophy), but spend the bulk of what is a science course on actual quantum mechanics theory.

The part about there being different bubbles of spacetime with different values for various constants seems like science since any model without such a postulate leaves our own spacetime too improbable to accept.

Multiverse is not just a QM thing, but it always seems related. Imagine I draw a line through Earth's north pole, out 100 billion light years, right now, cosmological coordinates. That defines a very specific location in a different universe. Do you deny that our spacetime extends at least that far? You'd be hard pressed to find a valid model that says it doesn't. Especially a classical one.

But what if I ask instead if there's a specific (albeit completely unknown) galaxy that happens to be closest to this arbitrary point in space I've defined? Now we're in philosophy territory. Science says nothing about that specific galaxy because it cannot ever be measured even in infinite time. So it suddenly ceases to be science despite science having no trouble talking about distances that large. It's not fiction, just something that cannot possibly affect us. The existence of the galaxy depends on the principle of counterfactual definiteness, and that principle is rejected in the majority of quantum interpretations and accepted only by ones with effect before cause and such. Still philosophy I think since the choice of models doesn't affect what's measured, but not an issue that should be lightly dismissed.

Is the multiverse science fiction only? Sabina seems to think so. — TiredThinker

If you feel gracious, you could label Many Worlds and Multiverse theories" as what-if "thought experiments". But, a lot of science fiction probably starts out that way. However, Some prominent scientists seem to take those conjectures seriously, as valid interpretations of Big Bang & Quantum paradoxes. Perhaps, because they see no other viable alternatives to the religious implications of a Creation Event, and an upward-pointing vector of Evolution & Time. However, Sabine prefers to call a spade a spade, and an imaginary reality an article of faith.

Yet, in Existential Physics, she does say, as a sop to serious scientists, that "it's a science-compatible belief system" But, after asking "are they real?", she replies : "unobservable universes are by definition unnecessary to describe what we observe". So, at the bottom line, she derisively labels MV, the "MultiWorse". Yet, she then adds, "you are welcome . . . to believe that copies of you exist, if you want, but there is no evidence this is actually correct". [my emphasis] :smile:

I wouldn't consider the interest in many physical worlds to be religious. If anything it brings more potential sufferings. Lol. Also it takes away emphasize from the choices we make here as we think of the better hand an alternate version of us may have been dealt. What experiments if any have been proposed to try to get evidence of alternate realities?

We are currently nowhere near having any kind of testable hypothesis for a multiverse. As a scientific idea it is one that may or may not be true and whether or not it is true it may or may not be useful to us.

I remember reading several years ago that hypothetically if we used all the nuclear weapons on Earth it was possible to open up a wormhole large enough to fit a spacecraft in … the major difference with that compared to the ‘multiverse’ is that we could actually test this and get a result.

There are numerous bizarre ideas from physicists because they are basically paid to think outside the box for a living. The ideas we ‘accept’ now are no less weirder (ie. Quantum stuff).

Well, we once believed in geocentrism. That was blown clean out of the water and replaced with heliocentrism; the same thing happened to the Milky Way galaxy, this was due to the observation of innumerable other galaxies which led us to this, our universe. There's this trend that's too obvious to miss (a steady demotion of earth and its inhabitants, especiaply us humans, from centerstage to the sidelines) - our universe is going to meet the same fate with the multiverse. The question that needs asking now is "what's there beyond the multiverse?"

https://m.youtube.com/watch?v=QHa1vbwVaNU

Is the multiverse science fiction only? Sabina seems to think so. — TiredThinker

The idea that there might be multi-universes is better than what we once had which was just there was a "big-bang" and there was nothing (or at least nothing to openly speak about) before it and/or anything that could have been created by something else. The problem with this kind of thinking is that didn't really allow for the discussion about anything we don't know about or even the problems with the given model.

For example, a few years ago I was on another forum trying to discuss what was going on with our universe the moment before (ie. time zero seconds passing in the start of our universe, which is (right before the big bang) and the person the created the opening post of the thread accused me of heresy since it was considered inappropriate to talk about such things in scientific circles even if the discussion was on a philosophical level. In a nutshell it was a bit of a headache for me because I believed that at least in philosophy anything can be considered and/or discussed where as the other forum member strongly disagreed. At least nowadays, it is less likely someone else would have to deal with this particle headache in such discussions although it is also less likely that such a person would want to create a thread for such a discussion.

While science fiction and other kinds of speculation often gets a bad rap from the "scientific elites" that are more focused on the facts and what we already know, it does provide a kind of fertile ground for people to create and share ideas as to what may be. For some science fiction isn't merely some kind of fertilizer for where futures ideas and theories to grow from, but it is actually on the vanguard of what the future will be for society, philosophy, and science itself.

While science fiction and other crack-pot ideas may sometimes be at best the red-headed stepchild of science, for others it is what true science is all about - experimentation and the expansion of our understanding into the unknown and the potential cost of one's own reputation among the scientific community as society as a whole. Those that are willing and able to open the door into theories and knowledge of areas not yet ventured make it potentially easier for others to then also venture down the same path. Sometimes the difference between sane/insane or fiction/non-fiction or really what is either accepted or not accepted) may just be how many have been down certain paths and documented them for those who choose to also venture them as well.

It you want proof of this just look at the history of Abrahamic religions. Often in the it's beginning, it's followers were labeled as heretics and their beliefs as mere fiction, but as time passed Western civilization more or less choose to accept such beliefs as "true" and "rational", although in modern times it is not so much so as it might have once have been. If Abrahamic religions didn't exist (or perhaps in areas where it hasn't been accept yet) such beliefs are considered non-sense and/or mere fiction.

Without institutions and/or other things to back certain pre-existing ideas or beliefs, there is hardly anything to separate what we consider to be fact and that which is fiction. What is even worse is with certain kinds of propaganda being spewed from various political and special groups nowadays it can be hard for the general public to be able to separate certain facts and fiction from each other.

Is the multiverse science fiction only? — TiredThinker

If we can model our reality better with multiverse models than without, then why wouldn't it be science?

Everybody ought to understand that it's a model of reality, not reality itself.

Not quite science, at least not at the moment, maybe some day?

Ethan Siegel writes:

This is why physicists suspect the Multiverse very likely exists (Big Think; Dec 2021)

I guess a few physicists/cosmologists find the idea compelling while going by current theories.

Don't you mean a model "for" reality? It isn't based on anything measurable yet?

You can say so. But I assume you got my point.

Is the multiverse science fiction only? Sabina seems to think so. — TiredThinker

As I mentioned in another thread, I see the multiverse concept as indicative of the emergence of a new scientific paradigm, coinciding with the increasing reliance of science on modeling and simulations. Which relates to the attempt to study/quantify/contextualize phenomena at an ever-increasing level of systemic-complexity. It would fit with what Popper calls a metaphysical research program.

Is the multiverse science fiction only? Sabina seems to think so. — TiredThinker

It's not a testable hypothesis, and it's not even entailed by accepted physics - so no, it's not Science.

It's not testable, reason can either accept or deny it (though it stretches credulity) and other theories can, in principle, produce similar results without relying on it.

Is it scientific? It's not clear. But it could be true, we just have no way to ascertain its veracity.

Great video! Thanks for sharing! :up:

***

I wrote down for myself --because I like doing that! :smile:-- 3 examples that serve as a good "exercise" in spotting and explaining unfounded, self-evident, self-explanatory, redundant, etc. satements. I copied them below, for anyone who may be interested ...

1. "We can say that a particle goes left or right, each with a 50% chance. But then, when we measure the particle, we find it either left or right, and then we know where it is with 100% confidence. So, what happened with the other percent outcome?"
a) The statement "when we measure the particle, we find it either left or right" is self-evident. Where else could there be? Is this what always happens with things that have 50% chances to be this or that, to go one way or the other?
b) The statement "and then we know where it is with 100% confidence" is also redundant.
c) The statement "what happened with the other percent outcome?" is a stupid question. It's like getting heads from tossing a coin and asking what happened to the tails?

2. "Anything that's possible is also real."
This is a fallacy, a wrong deduction. Real is something that happens or has happened. One could only say "Anything that's possible is potentially real." Which of course us a commonplace, self-explanatory, redundant.
And what about the example that is offered: "Maybe there's an elephant in front of you that you don't see it." Where is this possibility based on? On multiverses, I guess. But isn't this the subject matter itself that it is investigated? What's the meaning of proving the truth of a hypothesis by assuming it's already true?

3. "Every time a quantum object is measured, the universe splits to as many different universes as there were possible outcomes of the measurement."
Well, this certainly has its "quantum" explanation behind it, but I have a question: If we don't measure a quantum object, would there be no universe splitting? That is, split universes started to exist only after scientists were able measure quantum objects? It doesn't make any sense, does it?

Anyway, Sabine examines the subject from another, more interesting view and presents it in a much better way, of course.

If we can model our reality better with multiverse models than without, then why wouldn't it be science?
Everybody ought to understand that it's a model of reality, not reality itself. — ssu

There is a reality for each and every model, as implied and expressed by the models. Not the other way around. Choosing to call one of these realities 'reality itself' or 'really really real' is a personal choice no matter how many people are convinced otherwise.

There is a reality for each and every model, as implied and expressed by the models. Not the other way around. Choosing to call one of these realities 'reality itself' or 'really really real' is a personal choice no matter how many people are convinced otherwise. — magritte

So I attempt to make a clock and if it doesn't work and has no resemblance to a working clock, I'll just say my clock works just fine ...it's just not in this reality.

Well, that's one way to think about the multiverse I guess.

that's one way to think about the multiverse I guess — ssu

The multiple universe models are driven by mathematical logic as extensions of cosmological theories. The parameters of those theories turn out to be just numbers that happen to work for us, but are they necessary or just lucky? Could they have been some other way? Of course, any other way we would not be here to ask, but the numbers and the implied universes (read logical realities) that might have been simply wouldn't care. Does our presence bias our views on the matter so that reality boils down only to that which makes it possible for me to type this sentence?