The Multiverse just Got Bigger: An Upgrade for the Many Worlds Interpretation

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The idea of parallel universes is both crazy and not. In physics, it's prominently represented by the “Many Worlds” interpretation of quantum mechanics. A group of physicists now says that the many worlds interpretation contains many more worlds than we thought so far, meaning the infinite number of multiverses could be infinitely larger. Let’s have a look.
Paper: arxiv.org/abs/2403.10895
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#science #sciencenews #physics #multiverse

[@NDFlyFisher]

I had a statistics professor in grad school who was fond of saying, “If you torture numbers long enough you can get them to admit to anything.”

[@brothermine2292]

Another adage is "lies, damn lies, and statistics."

[@scotttovey]

Technically, it's not the numbers that are admitting to anything, the person manipulating the numbers, is simply lying. Anyone can come up with a theory of this or that, this is not a problem. I read an individuals interpretation of a Bible passage and then decided to read the Bible passage. The only way to get his interpretation to work, is to completely rewrite the passage. He however, was quite confident that his interpretation of the passage was valid. Problems do not come with the abundance of theories and ideas. Problems come with the abundance of pride and egotism that cannot handle when the fact of reality hits the theorist in the head. If one is so stuck on the brilliance of one's theory that one cannot be wrong, odds are greater that the theory is wrong and one is simply too busy being right to prove oneself wrong.

[@MagMar-kv9ne]

@@scotttovey Yup. A brilliant analysis. Thank you. Btw, it is EXTREMELY hard to overcome this problem. I had worked very shortly at college with reseachers - NOT physics, lol - and it is extremely widespread, this attempt at lying to yourself. I also caught myself doing it ;)

[@user-ek8gs4ij4r]

Brilliant.

[@serioustoday]

@@brothermine2292 Benjamin Disraeli?

[@People.United]

" ... at least I do in this universe." Best line ever.

[@martifingers]

Sabine's humour has one of the qualities of good comedy - the jokes arise entirely from the context.

[@danielcook1271]

Sabine, long term fan here. Have watched your channel evolve and you’re the best at what you do. I only wish this channel (and KZbin) existed when I was a teenager deciding on whether to pursue chemistry or physics at university. Your daily updates and explanations on quantum physics and general relativity give me precisely what this Einstein/Dirac/Feynman/Hossenfelder fan boy needs.

[@SabineHossenfelder]

Thanks for the kind words 😊

[@TheDdm1234]

​@@SabineHossenfelderdo you exist in the universe, or the multiverse, or both?

[@PPP-on3vl]

​@@SabineHossenfelder u are getting old

[@prototy]

I propose that we officially name a collection of particles a “party” of particles.

[@altrag]

Far too late. It was already named a "zoo" decades ago.

[@prototy]

@@altrag that’s just the name of the types of particles. “In particle physics, the term particle zoo is used colloquially to describe the relatively extensive list of known subatomic particles by comparison to the variety of species in a zoo.” There’s still room for a collection of particles to be called a “party” ❤️

[@phoenix007ism]

A partycle?

[@eljcd]

I love that with Sabine you always learn something new, but "the quanten" IS another level of knowledge...

[@hydewhyte4364]

She does make education entertaining ...

[@chris.hinsley]

It’s another level of socks !

[@matthiaseberlein3451]

@@8gjames Correct. It's "Die Quante" in German.

[@thesiegfried]

@@matthiaseberlein3451 Weirdly, I am a German and have never heard the word "Quante" with regard to feet before watching this video.

[@SomeoneExchangeable]

@@thesiegfried It is, as far as I know, Berlinerisch

[@wetwingnut]

I'm beginning to think that the problem with physics lies in physicists believing that the Mathematics and the Physics ARE THE SAME THING, rather than that mathematics is a (very powerful) framework for humans to conceptualize physical phenomena.

[@jjptech]

So, basically the problem with physics are physicists 😅

[@Olack87]

You are right of course to an extent. The problem is that often extremely abstract math have predicted real physical phenomena that no one would have guessed existed. A singularity in the equations of relativity predicted black holes before we had a chance to realize their true physical existence. So it's tough to tell when some mathematical crazy quantity indeed corresponds to real physics or is just evidence towards having a wrong theory.

[@TheGuyCalledX]

Exactly. Going deep into pure math, you'll find many things that have almost no real world applications, because they often don't have analogs to the physical world.

[@iyziejane]

You think a person who spends 10, 20, 30 years on theoretical physics does not have that thought? :P

[@HatsuneSquidward]

But the fact that it happens/ has happened ever, and surprisingly frequently at that, begs the question of if the universe is fundamentally mathematialcal in nature. If so this approach becomes more justified.@@TheGuyCalledX

[@christiandior8726]

Thank you for calling BS on bad papers! We need more people like you!

[@EinsteinsHair]

I just found a small channel called Sholto David. Some of his videos debunk things such as crystal healing. But other videos find published papers with manipulated data, or reused data. He has gotten a couple of papers retracted by journals.

[@mrfriendly9956]

"I like this paper, in this universe", perfect start!

[@sosomadman]

The quantum world is like a pair of glasses with the wrong prescription, with things appearing in 2 place at the same time

[@Thomas-gk42]

Measuring a new SH video sometimes opens a portal to another world. These guys must be right.

[@CosmosMarinerDU]

That is really a lovely compliment!

[@Thomas-gk42]

@@CosmosMarinerDU 😊

[@musesesesese]

Maybe the reason we can measure large objects and not quantum ones precisely is due to the fact that large objects are made of constantly interacting small objects that effectively just measure each other via interaction, we know once something interacts with it that it is determined, but im probably missing something edit: probably clearer to think of it as interaction with an object is necessary for measurement and quantum objects are not necessarily being interacted with prior to being measured, but macroscopic objects and their individual quantum parts are always interacting with each other. This doesnt mean that things are undetermined before being interacted with either, just that we wont be able to know the outcomes without some kind of data which we get from some interaction, making the interaction itself look like the cause, when it really could be that we are just missing something

[@altrag]

> but im probably missing something You are. You're missing the uncertainty principle. Even if we didn't have any "large objects" getting in the way, it would still be impossible to measure quantum objects precisely because they fundamentally aren't precise. To analogize (and please remember that all analogies are necessarily incorrect in some manner - if they were a perfect representation they wouldn't be analogies, they'd just be the thing!), think of plucking a guitar and then asking what point on the string is the "G". The question doesn't even really make sense - the "G" isn't a point on the string, it's the shape of the string's vibration - and if you want to dig deeper it's not even _just_ the string - it's the combination of the string you caused to vibrate, the air molecules the string caused to vibrate, the membrane in your ear (or on a microphone) that the air caused to vibrate, the neurons in your head (or the electronics picking up the microphone) doing... whatever they do... and so on. Of course that's just with our current understanding of quantum mechanics. It's anyone's guess what a deeper theory will reveal. There is reason to believe it won't go back to being a classical theory, but "reason to believe" is not proof. My personal guess is that whatever the next theory is will be as different from quantum mechanics as quantum is from classical mechanics - and be that much more difficult again for us mere mortals to understand with just our intuition.

[@lubricustheslippery5028]

@@altrag It's hard to know if "quantum object fundamentally aren't precise" because you can't measure it without interacting with it. I tried to read up on bells inequality theorem and no hidden variable theories and it just got more complex and less convincing the further towards real experiment I got. Sabine is always at point so watch this kzbin.info/www/bejne/jn2cqIqbetKErNE And it's not that easy to explain why the shoe analogy is not working, especially if you go from real observations and experiments instead of other theories that could be false.

[@camelCased]

Hm, I'm not sure about quantum objects not being interacted. They seem to be in constant interaction with other quantum objects, don't they? So, the question still remains - at what point and why does some kind of interaction cause them to suddenly behave differently than when they are interacting with each other on their own?

[@altrag]

@@camelCased > They seem to be in constant interaction with other quantum objects, don't they? If you're just talking about some arbitrary particle in some random place on Earth then sure. But we don't do quantum experiments in that context. We go to great lengths to eliminate those interactions specifically because it will "behave different" if you don't have full accounting of every single interaction the particle participates in. It's why pretty much all quantum experiments are done in a vibrationally-stabilized vacuum chamber at cryogenic temperatures, and often in a magnetic trap to boot. Anything we can do to prevent any stray particles or photons from interfering with the experiment. > at what point and why does some kind of interaction cause them to suddenly behave differently Yep, that is the question. One we don't have an answer to. We can measure it. We know it happens. But we have no idea _why_ it happens. Many worlds (whichever variety), Copenhagen's wave function collapse, pilot waves... these are all potential explanations, but they're all philosophy at this point. Mathematically they're all equivalent so there's no way to construct an experiment that would determine which one is "right" - if any of them. It's entirely possible (I'd even say likely) that the right answer is something we haven't even thought of yet. Until something new comes along to give us more insight, the "right" answer is simply the one that best helps you understand the problem you're working on - you can even use a different "right" answer for each problem you work on!

[@lubricustheslippery5028]

@@camelCased How do you now they behave differently when you can't observe it. You observing/measuring it is interacting with something big and less quantum. I can't either understand how it could be that it's binary the wave function either collapsed or not. I can imagine it's something more like the law of big number where interacting with more particles reduces the uncertainty similar on the more you have thrown an dice the mean will get closer to 3.5.

[@fabkury]

I secretly wish every major language of the world had its own Sabine-In-Chief. To communicate science and defend the people from myths.

[@havenbastion]

I believe she's carrying the Torch of Sagan.

[@chris.hinsley]

Your not listen clearly enough ! She is openly saying it’s all crap !!! :)

[@fabkury]

@@havenbastion I like your analogy.

[@ShonMardani]

@@chris.hinsley She is saying her audience is crap and germans figured it all out many years ago but it is too complicated for others to understand.

[@chris.hinsley]

@@ShonMardani well you are but what am I… to quote the Bart.

[@PatFarrellKTM]

“When you can measure what you are speaking about, and express it in numbers, you know something about it, when you cannot express it in numbers, your knowledge is of a meager and unsatisfactory kind; it may be the beginning of knowledge, but you have scarely, in your thoughts advanced to the stage of science.” ― William Thomson aka Lord Kelvin

[@BenjaminCronce]

I subscribe that the world is fundamentally abstract and attempting to force the world into an objective state is ultimately a false analogy. Heisenberg's uncertainty is but one of many forms of this. There are classes of problems that are fundamentally unsolvable if you attempt to objectify them and they only way to solve them is to treat them abstractly. There are cases of this that have happened in computer science. I remember reading a case where it was proven that a problem was unsolvable only to have it solved once someone created whole new axioms. This is the problem with reasoning. Godel's theorem says that there is no one complete system of logic. Sometimes the only way to solve a problem is to CHANGE LOGIC. This is an abstract problem. I actually recently watched a math video talking about a problem that was claimed to have been solved millennia ago, but when modern mathematicians attempted to investigate it, not only did they discover that the documented solution did not solve the problem, but that the problem was proven to be unsolvable. It took several centuries of modern math before someone realized that that mathematical system from back when was actually different and that if you changed the rules of math, the problem was solved, and was an actual solution. It wasn't just playing with math to make a useless solution, but an actual real solution. Our modern math was unable to solve the problem. Numbers themselves are but abstract concepts that do not actually exist and their value only exists within whichever mathematical system you choose to use.

[@johnrowson2253]

A historical perspective of mathematics helps explain interpretative problems. When algebra was being used during the ‘dark ages’, there were crazy ideas about ‘x’. Two authors I recommend are Mario Livio who has several titles about the history of stem, and Nick Lucid.

[@G3Kappa]

It would be cool if you actually explained what those crazy ideas were lol

[@brianhourigan]

​@@G3Kappa x was y and z at the same time. Superentangelbra

[@waltergith6535]

Wow, this is epic Sabine. The question what a measurement is and whether an observer exists or not is groundbreaking. Physicists are really onto something here. Could you please follow up with more videos on every aspect of those questions. Thank you.

[@fabriciotoscano7185]

Your approach to physics is the best ! Well done ! 👏🏾👏🏾👏🏾

[@benlap1977]

The world of physics is like Disney Studios in the 80s: trying to recreate the past glory, but running out of ideas.

[@Mlab923]

You should get patent for your words.

[@audiodead7302]

I agree that the flailing around of the current physics community shows a lack of coherence direction. But maybe that is what is needed before a new direction emerges.

[@rayalbrektson5559]

Physics needs a “Michael Eisner” . . .

[@benlap1977]

@audiodead7302 I do agree. Evolution is never linear and always came in leaps. There are periods in the doldrums where not much seems to happen and there are periods of explosion. It certainly feels like quantum physics is in the doldrums. Astrophysics, on the other hand, is exploding.

[@altrag]

Just like it's always been. The real "problem" with physics is that the last great paradigm shift happened recently enough that it's still fresh in mind (culturally speaking) but at the same time long enough ago that we current generations feel like we "missed out". Prior to the late 1800s, nothing super exciting had really happened in physics for like 200 years. And prior to that period in the 1500-1600s (including Galileo, Kepler, Newton and that group - the people who defined the basis for what we now call classical physics), there wasn't any major leaps since the time of Euclid. Not to say _nothing_ happened during those periods of course. People were and still are making incremental improvements to the knowledge that existed at the time. But there's really only been 3-4 massive paradigm shifts throughout all of history - the Greeks introducing concepts like mathematical rigor and logic into the study of "natural philosophy" (possibly divided into a couple of separate movements if you want to split pre-Euclid focusing primarily on logic, and post-Euclid that demands the rigor aspect), classical mechanics (primarily initiated during the 1500s-1600s as noted) and quantum mechanics (initiated in the late 1800s up to the mid 1900s). That's really not a lot when you think about it in historical terms. We currently just happen to be in one of those "incremental improvement" periods and waiting on the next paradigm shift. Drawing a trend line across the previous 3-4 makes it feel like there's an exponentially decreasing amount of time between paradigm shifts, but 3 data points is not really a solid basis for making that kind of claim. We really shouldn't expect the next paradigm shift within our lifetimes - realistically that's _probably_ not going to happen. It might of course, but it's not something to place bets on.

[@davidtatro7457]

The best thing about this is contemplating the sheer magnitude of cheese and kitty cats that might exist in all these extra worlds.

[@michealcherrington6531]

keep counting!

[@Infinite_Horizonsss]

Thank you for the video 🎉

[@samedwards6683]

Thanks so much for creating and sharing this informative video. Great job. Keep it up.

[@NeonVisual]

Dark energy is just a rounding error by the dev of universe.exe

[@chris.hinsley]

Floating point formats are crap aren’t they !!!

[@SigEpBlue]

Oh man, if this universe runs Windows....

[@chris.hinsley]

@@SigEpBlue blue screen of big bang….

[@valrond]

@@SigEpBlue More like Universes OS

[@chris.hinsley]

Sabine should cover p-adic number systems…. In her own sweet way.

[@seanmostert4213]

Thank you for sharing Sabine. I would like to propose an alternative hypothesis that might offer a fresh perspective on the nature of "what a measurement is" in the context of quantum mechanics. 1.) Consider, for a moment, the analogy of the wave function of a particle in superposition akin to a Lagrange point in classical mechanics-a position of equilibrium between competing forces. In the quantum realm, these equilibrium points may manifest as multiple potential states within a superposition, each acting as a tipping point that could influence the path of state reduction upon measurement. 2.) From a geometric standpoint, we define a "point" as an exact location in space and a "line" as a continuum of points. These concepts are integral to the process of measurement, which fundamentally involves distinguishing a specific state from the realm of possibilities. In essence, to measure is to define what something is by discerning it from what it is not, employing a comparative framework that leverages change between two diametrically opposed states. When an observation or measurement is made on a particle in a state of superposition, it necessarily influences the system. This influence can be conceptualized as imposing a 'change'-akin to introducing a fluctuation or disturbance-that tips the system over one of these quantum Lagrange points. Moreover, consider the broader concept of 'change' as analogous to vibration, which encompasses regular or periodic motions around a central position or fluctuations within a system. This metaphor extends aptly to quantum mechanics, where the wave function itself represents a form of vibration. Therefore, when we interact with a superposition by measuring it, we are essentially interacting with the vibrational state of the wave function, introducing new vibrations that affect that wave, that then results in a definitive state. I am eager to hear your thoughts on this hypothesis and whether such a conceptual framework might contribute to our understanding of quantum measurements.

[@SabineHossenfelder]

The problem is to do it locally.

[@seanmostert4213]

@@SabineHossenfelder would cryogenic temperatures slow down the effects enough so that they can be measured momentarily before collapsing into a state?

[@Thomas-gk42]

@@seanmostert4213 I´ve heard, that Sabine peopose an experiment like that, 10years ago, that never was tested,...well, perhaps I misunderstood the connections.

[@iyziejane]

What you are describing is called a "hidden variable theory", the idea that quantum features such as the uncertainty principle or wave- mechanics could be caused by unknown hidden interactions. The uncertainty principle and wave functions are often taught to people in terms of a single particle. But a special quantum effect called entanglement occurs when you have more than one particle interacting. Entanglement is the part of quantum theory that can't be explained convincingly by hidden variables. Experiments with entanglement (e.g. Bell's inequality) force us to accept that something very strange happens at the quantum level. As Sabine says, "the trouble is to do it locally", she means that to explain the results of Bell's experiment, the hidden variables could not act "locally" when we perform measurements on entangled particles that are separated in space.

[@Thomas-gk42]

@@iyziejane But what I know from her papers is that Sabine herself works on a hidden variables theory, sometimes called superdeterminsm.You have either to give up locality, what classical QM has done, or the postulate of statistical independence connecting the measurement outcome with the detector setting, what superdeterminism does. As I said, she made some experimental proposals to test it (similar to the first commenter), but none of them were implemented.

[@milkibearmilkibear]

Another amazing video, definitely going to read the paper, also than you for the brilliant discount!!! :)

[@andreaoldofredi3436]

Sabine (if I may) your videos are excellent! Very clearly articulated, precise and easy to follow. A pleasure to watch!

[@Thomas-gk42]

A pleasure, yes indeed!

[@Sharon-hr2]

Out of all worlds, why did I get stuck in the one where people believe in many worlds?

[@grahamritchie672]

Better than being in the one where Elvis died.

[@wb3904]

At least in this world your body can form, KZbin exists and you can formulate this response 😊

[@LuisSierra42]

@@grahamritchie672 In my world Elvis is immortal

[@mathiaslist6705]

What is wrong about it? Unless they interact with our one it doesn't matter or should it?

[@not2busy]

...because people are infinitely gullible.

[@mskiptr]

This all (both the paper and the video) sound like a severe misunderstanding of the MWI. It's only about "worlds" in sci-fi (and pop-sci, but that's often the same thing). From the mathematical perspective it's just about not having some special observers that cannot be in a superposition of two base states for whatever reason. Whenever you have an experiment where you measure something and "cause a collapse", MWI says that there wasn't any collapse and the measurement aparatus is just entangled with the experiment now. The aparatus behaves as if it had measured only one base state because you're only considering exactly one base state for the aparatus. That's it.

[@MrSpikegee]

Same here. Sabine hates the many world interpretation for some reason and will take any occasion to step on it, like this last paper which seems really d.

[@mskiptr]

@@MrSpikegee I guess she thinks it's about "parallel worlds" and that the entire reason for it is to "get rid of randomness by choosing every possible outcome". That would indeed be pretty pointless, but that's sadly how MWI is often presented.

[@altrag]

Funny thing is, it doesn't really matter. The math is the same either way, so until we can get a better understanding of what a "collapse" really is, the interpretations we use to describe it are mostly just personal preference. Relating this paper to your preferred interpretation (and mine if I'm being honest), it would imply that the state space getting entangled is larger than we thought rather than the multiplicity of universes being larger than we thought.

[@toddturner6]

And there you have it. This man is correct. Somebody give him an award or something for pointing it out. At least a cookie? 🍪😊

[@sh4dow666]

@@altrag The math is *mostly* the same, except the MWI doesn't need an additional collapse postulate. You can cheat a bit by not including the collapse in your equations ((and applying it "off the books" afterwards)), but that doesn't change the fact that the Copenhagen interpretation requires an additional mechanism (ie. "spooky action at a distance").

[@Yuri_Panbolsky]

From classical to physical realizable Hamiltonian Mechanics - kzbin.info/www/bejne/fWm1dWiBmal-eqc

[@eonasjohn]

Thank you for the video.

[@europaeuropa3673]

My mind keeps drifting toward mental instability, the more I try to accept quantum mechanics.

[@ronburk5135]

So in other words. It's turtles all the way down.

[@user-Mike755]

Thank you Sabine!

[@Nostrudoomus]

Thank you, Sabine!

[@Nomaken2]

Basically i think the mistake is in assuming photons move because we lose energy in one place and gain it in another and the distance and time between them implies there was linear movement.

[@EinsteinsHair]

You can have a tabletop experiment with a laser pointed at a target. Then you can blow smoke everywhere between the two, and the smoke will light up as if the photons were within a narrow path all the way between the laser and target. Lying photons!

[@marcuscarana9240]

Standup comedian with a phd in theoretical physics: Population: Sabine

[@nikbivation]

wow amazing, thank you for this insight!

[@OrlandoRenato74]

Love your Chanel Sabine....tus puntos de vistas siempre cuestionan muchas opciones de interpretación alternativas....Out of de box...saludos dese Peru❤

[@MadridBarcelonaRota]

But Sabine, our ability to observe with all our senses must always mean that we are continuously measuring everything we are aware of. To my mind we are only aware of what we are aware of. We cannot be aware of what we are not aware of so every thing we are aware of is in a state of being measured by ourselves. Thus the quantum field is continuously collapsed to what we have measured it to be. Happy to concede my measurements are not necessarily exactly coincident with yours.

[@SabineHossenfelder]

So how come that whenever two people compare what measurement results they have become aware of they find the same thing?

[@luke7111]

​@@SabineHossenfelder hi, idk if you could help me a scientific opinion on my lay man understanding isn't measurement just the observation we make with our brains? i don't understand why there's a question about it for example, if i smell something, my brain creates the 'understanding' of what im smelling if its something ive labelled - lets say cheese - i will recall that and refer to it that way. i've observed the small of cheese! the thing did not collapse into cheese from an undefined set of properties because i smelled it i were able to observe it as such because it already has been collasped to begin with kinda like from the beginning, the particles just ended up being cheese if another person does an observation they will come to the same conclusion same as in - their brains will take the process of recollection and labelling. if they labelled that smell as cheese before, they would do that and agree with me if somehow they were tricked to think cheese is called chocolate, they would say its chocolate and say their measurement is different its still 'cheese' in a way, but its also 'chocolate', so u could almost say the state collapsed differently for them but not because the 'thing' in question was in different undefined states - but rather that their own state wasn't the same as mine so relatively speaking, their view point or frame of reference prevented them from observing it the same way ive' had or something? uhh, kind of weird to write that makes my brain almost think that the whole super position stuff is just that is u have more than 2 things, 3+ - A B C, each thing looks at each other differently cause they cannot be in the exact same position at the same time like if i imagine a triangle of particles A - B \ / C each can only see the other in a very limited way, A only sees B's left side C see's B's left/bottom side B doesnt' see itself at all and if that applies to all particles in the universe at the same time, observing from any position relative to other gives a different result, but they are still A B and C; we just saw it from different perspective so it seems like they are different measurements, almost like particles changed based no how we looked, idk? in some human brain way they did 'change' but physically they haven't? they just 'interacted' (which is what observation is from like human perspective rigth) differently cuz of where im standing? tbf kind of fun being prompted to think too much from the video ha ha

[@wb3904]

That's why you never see a quantum state directly. Every observation causes or is the result of a wave collapse.

[@FalkFlak]

The question is, why would a consciousness measure anything else? Is there more than one MOST probable measurement? I know this borders on metaphysics but I find it absolutely unterstandable that the consciousness (tries to!!) only construct "measurements" that are in line with what every other conciousness would measure. So, for example every brain would measure a reality in which the big bang most likely would had happened even if it doesn't measured it in that instant because it's the only causal connection that works with every other particle in the universe. They all Connect to each other, I don't need to measure every single one of them.

[@wb3904]

@@FalkFlak it's not consciousness itself. As I understand it, it's when a particle like a photon hits your eye it has a definite position and the wave function collapses, going to a single state.

[@ratedrmartian]

Quantum mechanics is definitely weird but that's what I like about physics stuff I possibly couldn't know everything about it

[@Mark8v29]

I enjoy the description of the measurement problem implied in the Futurama TV series.

[@sabinrawr]

I've given a lot of thought to Many Worlds, but from a conceptual position rather than mathematical. I'm not convinced by it, but some interesting ideas emerged. Imagine my consciousness as a wave function. It can only perceive things whose waves are in-phase with mine. It's not that a particle is found to exist in different places in different separate universes, but that the particle is, and remains, in its superposition through measurement... but we only observe the position that is in-phase with ourselves. There are not infinitely many different versions of reality, just infinitely many different stories about it. We might even consider the possibility that inexplicable phenomena (like ghosts, the Mandela effect, or déjà vu) might be parts of this reality that are nearly in-phase but not quite. If true, it's interesting to think what might be possible if we could shift our own wave phase to experience a different version of reality that's more to our liking... maybe one without stinky feet! Edit to add this: if the universe is actually deterministic (think: block universe), it might be that the only part not yet determined is which "version" we will experience. Perhaps all possible versions already do exist in eternal superposition, but our experience will depend on how our consciousness evolves through our choices.

[@hydewhyte4364]

This is why physicists throw the best parties.

[@chris.hinsley]

Not until we can come up with some system that makes all of Sabine’s clothes jump 3 feet to the left…

[@MichaelWinter-ss6lx]

The atoms of the clothes are to jump two feet to the left.

[@chris.hinsley]

@@MichaelWinter-ss6lx left or right the end result is okay with me.

[@I.amthatrealJuan]

Like Hawking's time traveller party

[@baomao7243]

Hell raisers

[@carlbrenninkmeijer8925]

A brilliant explanation, thanks a lot !! I also like your cat(s).

[@Zothaqqua]

Since *I* am the only measurement device, I look forward to one of the results of the research you mention when I decide to look at it.

[@kilianklaiber6367]

Your videos are getting better and better. You appear to be ready for asking the hard questions and standing up against the crowd..., i.e. the "consensus".

[@lifeofgaurz]

The way you talk about complex topics is AMAZING

[@rayalbrektson5559]

“Multiverse fanatics” 😂😂😂 You nailed the problem right there.

[@Thomas-gk42]

HIhi, my thought!

Nice video Sabine, I agree 100% with it

[@b.munster2830]

I think it’s much simpler than some physicists do make believe. QM is a way to predict probabilities of measurement outcomes in the FUTURE. (This does not necessarily relate to future measurements themselves, but rather to future knowledge of the outcomes. For example, when Schrödinger’s cat is put in the box and the lid is closed, anything that happens to the cat is future knowledge for observers outside the box until the box is opened, while the cat itself is an observer inside the box who knows when the toxic gas is released). Indeed, all possible outcomes (which define many possible worlds) coexist at present. But possible outcomes are theoretical only, they are not real outcomes. Therefore, the many worlds are also theoretical only, i.e. not real. Only when the real outcomes are known, it becomes clear which of the many possible worlds has become reality. If the toxic gas is released in the box, the cat can know (e.g. smell) it earlier than outside observers. When a measurement outcome becomes a known fact (i.e. reality), that is the moment when the wave function (for future predictions) collapses. It’s really just like playing dice. The probability of throwing two sixes in a row is 1/36, but once the first six is thrown, we can rule out all other possibilities, and the probability of throwing a second six has collapsed to 1/6. There is nothing strange about that. The only case where QM is strange and doesn’t behave like playing dice, is in the correlation of entangled particles, even at great distances. I wish scientists could come up with a better explanation for that.

[@TerryBollinger]

5:32 _"I am convinced that the next breakthrough in physics will come from figuring out just what a measurement is."_ Quantum observation is acceleration. No matter how minute - one photon is fine even for a large object - acceleration nudges a self-contained quantum system (particle or internally bound object) into a slightly different inertial frame. Observation is always a two-way business since acceleration converts a tiny bit of energy into an action-reaction momentum pair that establishes a mutual observation (knowledge) of each entity of the other. Most of the confusion on this issue comes from conflating two very different processes. The first process is energized transformation, such as converting an electron in its low-energy atomic orbital cloud form into an expanding waveform that we associate with an ejected particle, often dubiously at these small scales. That's about as quantum as emptying a puddle by pumping it out of a more localized squirting nozzle. You only get the desired transformation if you have enough energy. The second process is spacetime uncertainty collapse. This is the "true" quantum collapse, initiated by even the tiniest shift in the relativistic frame. You don't notice this much in condensed matter because atoms reside at the boundary of sufficiently rapid observation through small momentum exchanges - mostly phonons - to keep them fully localized relative to each other, thus keeping _space_ well-defined. Even if unknowingly, this is why Einstein was always keen on using physical rulers when setting up his thought problem coordinate systems. The tricky part of the second process - well, the other tricky part, since most folks don't like thinking of space and time as nothing more than local-only subsets of how the universe handles separation and change - is that the energy needed to fund spacetime uncertainty collapse can be so astronomically low that it becomes tempting to treat it as not existing at all - that is, to call it a "pure" wave function. Quantum cats die using the first process, energy transformation. This happens and is irreversible even if they stay out of touch with the universe for a while. Quantum cats end up _positioned_ within an observer's space using the second process of spacetime uncertainty collapse. They can still interfere through, say, an unusually large two-slit experiment, regardless of their dead-or-alive state. But extending this extremely narrow version of _location_ uncertainty to the cat's internal state is a serious modeling error.

[@riveteye93]

I'm very impressed that I almost understood what you wrote. I mean, thought I understood it, until someone will observe my mind it will remain a quantum mystery.

[@TerryBollinger]

​@@riveteye93, thanks. First, I like your Ano Nymous handle. It's a pretty cool parsing of the word. The nice thing about acceleration as observation is it makes sense classically. After all, if someone bumps into you, you know where that person is, and they now know where you are. You have no clue where they are if they don't bump into you. What's remarkable is that _every_ case imaginable of quantum "collapse" involves at least a tiny, but always measurable, "bump" of some sort. Some of these, such as photons bouncing off of solar sails, are nothing _but_ tiny momentum bumps. Those don't fit well with quantum field theory. I would encourage anyone reading this to post an example to the contrary. If you think you have one, I'd love to hear it. The deeper question is why bumps are so important and how they can make such a remarkable difference on the scale of quantum wave functions. That is... fascinating but also a bit mind-bending. Our brains are not wired to think that way. You must reach into networking theory, like how the Internet keeps itself sane despite global delays in how fast information is traded. Here's an analogy that works upsettingly well: Acceleration is vital because until it happens, _each of us lives in our own isolated universe._ That's almost impossible in the classical world, and that's the point: All the constant jostling at every scale imaginable is what _keeps_ our world classical. The problem is that as you get smaller, your particle-sized universe quickly starts losing track of where it is within the larger universe, much like trying to walk with your eyes closed. Even worse, your tiny universe _expands_ as it loses track, making its final location even harder to figure out. We call that result a "wave function," but even that is not quite right. Like particles, waves are possible _only_ when defined to an existing coordinate system, such as a mirror or hologram. The word I've been using for the isolation that occurs without bumping is Sanscrit _nirakar_ ("near-a-car"), meaning unformed. This is the most promising approach mathematically, but it is very algorithmic. No points are allowed, for example, since those become unreachable, infinitely costly limits. So much for infinitely precise number lines! It's intriguing and likely much easier computationally by not overpresuming how much detail is needed to model a problem. Finally, the nice thing about acceleration collapse and the quantum state of your mind is that all you need to do to get your mind back in synch with the local universe is whack yourself on the side of the head... :)

[@andrewbouskill5444]

Time is faster than light. Quantum mechanics describes the action of time.

[@amihartz]

how can time have a speed? what does it even mean to assign a velocity to time?

[@andrewbouskill5444]

It means the rate at which reality occurs in the present moment is faster than light. It may be that on the quantum scale, where the tiniest of particles interact, causality can be broken. Take quantum tunneling, for instance, where the particle seems to break light speed once it trespasses the energy wall. Suppose the particle is taking a quantum pathway backward in time before the barrier was there in the first place and then jumping back to the present.

[@amihartz]

@@andrewbouskill5444 How can you assign a speed to the "rate at which reality occurs" when speed is defined in terms of time? Linguistically it does not even make sense what you are writing. Light moves at about 300 km/s, the only way to say something can move "faster" than it is if you can also express its speed in terms of km/s (if you cannot, then it linguistically makes no sense to say it is "faster"). So what km/s does time move at? 450 km/s? 1000 km/s? If time moves at a speed defined in terms of km/s, then how is this not viciously circular given that part of the definition of its speed is itself?

[@Notsogoodguitarguy]

Thank you, Sabine! You don't know if we exist, yet you still take the effort to explain things to us.

[@Yezpahr]

The segue to the sponsor was measured as smooth to the touch.

[@StabilisingGlobalTemperature]

Just because we cannot measure something does not mean it does not exist. Falling trees in forests etc.

[@chris.hinsley]

Thing is when you end up in the wood chipper I think everyone’s going to be able to hear that.

[@brothermine2292]

>chris.hinsley : If the wood-chipper is in space, no one can hear you scream.

[@chris.hinsley]

@@brothermine2292 you can feel the rumble through the decking plates though !!!

[@collin4555]

Kind of fundamental to quantum theory, Heisenberg Uncertainty and all that

[@Ciremo]

Maybe it doesn't exist, regardless of if we can measure it or not.

[@qazsedcft2162]

Thanks Sabine for telling me I don't exist. 🤣

[@JackdeDuCoeur]

What I most enjoy about science practice and its principal product, the scientific paper, is the vast territory comprising the space between the data and conclusions.

[@MCsCreations]

Fascinating! Thanks, Sabine!!! 😊 Stay safe there with your family! 🖖😊 (In some other universe I'm that cat, I'm sure of it. 😬)

[@djayjp]

A "measurement" occurs anytime something becomes entangled with something else. Btw technically the MWI postulates a near-infinite multiverse, not infinite (though presumably future infinite).

[@innocentsmith6091]

How is it only near infinite when wavefunctions are continuous? Shouldn't any real number position be possible?

[@nightknight6947]

yes yes I see. vbery intereting all this. 7/5.

[@absalomdraconis]

​@@innocentsmith6091: I'm not _certain_ what "presumably future infinite" in OP's post means, but I _suspect_ it means "constantly growing larger, and thus closer to infinite".

[@thomasgoodwin2648]

At the singularity of the universe all energies are in a single wave state, no further entanglement needed. Does it observe itself?

[@SabineHossenfelder]

If a particle decays into two particles, that creates an entangled state, yet it's clearly not a measurement.

[@DragoNate]

physicists: "INFINITY COULD BE INFINITELY MORE INFINITE!" can we get these interested in videogames or something? they seem bored.

[@LuisAldamiz]

I'm beginning to think that Heisenberg made it all up. Quantum is electrons interacting with photons in discrete packages (much as cups don't spill water until exactly the point of filling), all the rest seems a bit dubious.

[@peregrinemccauley5010]

Sabine is well versed on this matter.

[@osmosisjones4912]

Isn't the cat conscious

[@nextlevelenglish5858]

yes, and you would need to do this in a vacuum, so it would die before the experiment

[@TheMrCougarful]

We invented consciousness, and then abandoned it as a flawed idea.

[@osmosisjones4912]

@@TheMrCougarful conscious invented US

[@alieninmybeverage]

Out of all worlds, why did I get stuck in the one where people believe in many worlds?!

[@nextlevelenglish5858]

and you can disprove it how?

[@alieninmybeverage]

@nextlevelenglish5858 I certainly cannot. In fact, I apologize that this came across critically rather than tongue-in-cheek. I will say that I suspect that multiverse theories are the more the result of cynical rationale than naivety when it comes to the scientific/academic community. It appears to me an attempt to recreate the success of drake's equation in addressing the cross section necessary/sufficient conditions and elements we tend to intuit as "design" features that become enticing to rationalize as design/purposive if the universe is once-and-done, as if in response to evidence that the universe is not cyclical. It's a sort of "bayesian projection" onto the mystery.

[@Regalert]

I guess what changes with big objects (classical) and tiny ones (quantum) is speed: the tinniest the thing, the faster it moves. And velocity maybe be they "key" ("door") to olther dimensions. Another thing, our experience could be the interations of particles in interacting on different scales (speeds) , hence creating patterns (realities), as system...

[@itwontbeTV]

Sabine has this soft teaching approach when it comes to her quantum mechanic videos. Thank you Sabine!

[@Nathan-vt1jz]

I think multiverse theories should be evaluated philosophically as it’s not positively testable or verifiable as a scientific theory. There’s nothing wrong with a philosophical theory or religious belief, they just are evaluated differently. We all have such beliefs/theories, we should just recognize the scientific method is limited in how it can address such topics.

[@jimroth7927]

Some forms of "many worlds" might be testable. If we assume that each world has randomly assigned local physical laws independent of other worlds then, yes, not testable. On the other hand, if we assume that some universal laws of nature create all the worlds and determine the local laws of each world, then the universal laws might be discoverable and testable by observing the local laws in our world. I.E. The possible universal laws might be sufficiently limited by logical constraints and by local observations to rule out all but one set of universal laws.

[@JeppeAchtonNielsen]

​@@jimroth7927 My biggest objection to that is that we are already over interpolating our results. All of our experiments have been performed in a tiny solar system, which only represent a miniscule part of the assumed observable universe. Know you want to extend the interpolation further and describe multiple or even potentially infinite universes based on such a small sample size... Imagine for a moment the consequences if we discovered that several of our well established physical constants are in fact variable depending on location... and the only way to figure that out is to get of this tiny piece of dust and go somewhere else. We might just discover that several of our well established assumptions and interpretations are in fact completely wrong. Of course until we do that we are stuck with what we have, but can we please stop wasting time and energy on useless interpolations that can be tweaked infinitely to apply for more funding for theoretical physicists.

[@michaelraine8111]

I think a measurement is a decision point in an infinitely small moment of time so that our consciousness is continuously making measurements; because consciousness is doing this, it can never be measured!

[@HardcoreHokage-cw4uq]

Like the Greek philosopher Zeno who postulated the paradox before you can ever reach your destination, you must travel halfway there, always leaving another half. If there's always a smaller "half" to be taken, how could you ever arrive to the place you're headed?

[@travispalen3107]

Thank you for showing an example of "twiddling thumbs" @2:39 so that some of us know what you mean

[@Thomas-gk42]

Her use of hands and arms for explaining us difficult physical phenomenon is priceless and hilarious.

[@marcobiagini1878]

My name is Marco Biagini and I am a physicist; I want to explain the “observation” problem in quantum mechanics because it is often misunderstood even by many physicists. In quantum mechanics the state of a physical system is described by the wave function and does not have defined values ​​for all the physical quantities measurable on it; on the other hand, only the probability distributions relating to the measurable values ​​for these quantities are defined. Once the measurement has been carried out, the system will have a defined value in relation to the measured quantity, and this involves a radical modification of its wave function; in fact the wave function generally describes infinite possibilities while for an event to take place, it is necessary that the wave function assigns a probability of 100% to a single possibility and 0% probability to all the others. If all other results are not eliminated by imposing the collapse "by hand" on the wave function, the predictions of subsequent measurements on the same system will be wrong. The transition between a state that describes many possibilities to a state that describes only one possibility is called “collapse of the wave function”. The time evolution of the wave function is determined by Schrödinger's equation, but this equation never determines the collapse of the wave function, which instead is imposed by the physicist "by hand"; the collapse represents a violation of the Schrödinger equation, and the cause of the collapse is therefore attributable only to an agent not described by the Schrödinger equation itself. The open problem in quantum physics is that the cause of the transition between the indeterminate state and the determined state, cannot be traced back to any physical interaction, because all known physical interactions are already included in the Schrödinger's equation; in fact, the collapse of the wave function is a violation of the Schrodinger's equation, i.e. a violation of the most fundamental laws of physics and therefore the cause of the collapse cannot be determined by the same laws of physics, in particular, it cannot be determined by the interactions already included in the Schrodinger's equation. After one century of debates, the problem of measurement in quantum mechanics is still open and still represents the crucial problem for all interpretations of quantum mechanics. In fact, on the one hand it represents a violation of the Schrodinger equation, that is, a violation of the fundamental laws of physics. On the other hand, it is necessary for the laws of quantum physics to make sense, and to be applied in the interpretation and prediction of the phenomena we observe. Indeed, since the wave function represents infinite possibilities, without the collapse there would be no event; for there to be an event, then there must be one possibility that is actualized by canceling all other possibilities. This is the inescapable contradiction against which, all attempts to reconcile quantum physics with realism, break. Quantum mechanics does not describe reality as something that exists objectively at every instant, but as a collection of events isolated in time (i.e. the phenomena we observe at the very moment in which we observe them), while among these events there are only infinite possibilities and there is no continuity between events. In fact, the properties of a physical system are determined only after the collapse of the wave function; when the properties of the system are not yet determined, the system is not real, but only an idea, a hypothesis. Only when collapse occurs do properties become real because they take on a definite value. It makes no sense to assume that the system exists but its properties are indeterminate, because properties are an intrinsic aspect of the system itself; for example, there can be no triangle with indeterminate sides and no circle with indeterminate radius. Indeterminate properties means that properties do not exist which implies that the system itself does not exist; actually photons, electrons and quantum particles in general are just the name we give to some mathematical equations. The collapse represents the transition from infinite hypothetical possibilities to an actual event. Quantum mechanics is therefore incompatible with realism (that's why Einstein never accepted quantum mechanics); all alleged attempts to reconcile quantum mechanics with realism are flawed. The collapse of the wave function represents a non-physical event, since it violates the fundamental laws of physics, and can be associated with the only non-physical event we know of, consciousness. Therefore, events can only exist when consciousness is involved in the process. However, the fact that properties are created when a conscious mind observes the system in no way implies that it is the observer or his mind that creates those properties and causes the collapse; I regard this hypothesis as totally unreasonable (by the way, the universe is supposed to have existed even before the existence of humans). The point is that there must be a correlation between the existence of an event (associated to the collapse of the wave function =violation of the physical laws) and the interaction with a non-physical agent (the human mind); however, correlation does not mean causation because the concomitance of two events does not imply a causal link. No cause of collapse is necessary in an idealistic perspective, which assumes that there is no mind-independent physical reality and that physical reality exists as a concept in the mind of God that directly creates the phenomena we observe in our mind (any observed phenomenon is a mental experience) ; the collapse of the wave function is only a representation of God's act of creation in our mind of the observed phenomenon and is an element of the algorithm we have developed to make predictions and describe the phenomena we observe. This is essentially the view of the Irish philosopher George Berkeley, and in this view God is not only the Creator, but also the Sustainer of the universe. The fundamental aspect of quantum mechanics is that reality is not described as a continuum of events but as isolated events, and this is in perfect agreement with the idealistic view which presupposes that what we call "universe" is only the set of our sensory perceptions and that the idea that an external physical reality exists independently of the mind is only the product of our imagination; in other words, the universe is like a collective dream created by God in our mind. Idealism provides the only logically consistent interpretation of quantum mechanics, but most physicists do not accept idealism because it contradicts their personal beliefs, so they prefer an objectively wrong interpretation that gives them the illusion that quantum mechanics is compatible with realism.

[@Thomas-gk42]

" Idealism provides the only logically consitent interpratation of quantum mechanics" -- that´s ideological pseudoscientific nonsense.

[@minimal3734]

Hello my friend, I'm a physicist too. I have been intrigued by these questions for a long time and came to the conclusion that there is no 'measurement' and that there is no 'collapse' of the wave function. These unfortunate ideas have solely been introduced because the group of physicists could not cope with the observations otherwise. Therefore the name 'Copenhagen' :)

[@G3Kappa]

Isn't that just a very long-winded way to imply that the God of the Gaps is behind it all? It's not a satisfactory answer for a physicist. To me it just seems like a misguided conclusion that is impossible to prove and therefore not interesting or useful when it comes to describing the inner workings of reality. You can use that framework to claim anything and its opposite. That's just unscientific. The second you say something like "physical reality exists as a concept in the mind of God" you throw away all of your credibility, even if you're using big technical words to make your point.

[@Thomas-gk42]

@@minimal3734 I think this is a bot, saw a similar comment some other times. But your interpretation of Denmark´s capital is funny. So you refer to a hidden variable´s theory?

[@Thomas-gk42]

@@G3Kappa Entirely correct.

[@IzudeDarkwolf]

The main flaw I've found in quantum theories is misunderstanding of their tools and the limits of our observations. It's cherry-picked possibilities and ignoring the importance of falsification in the scientific method. We can't prove what is true, but we can prove what isn't. For example, superposition is likely a mathematical artifact from the planck scale, the physical limitation on our ability to quantize observations along with our common refusal to accept that every and any scientific "fact", that is appropriately called a theory, are educated guesses by recognizing patterns in correlations.

[@sacielo]

I'd wish to hear more about QFT from Sabine's videos. I'd find it inspiring, I'm sure.

[@neutronium_goes_wild]

the latest proposed hypothesis is the universe is basically a planck relic of a black hole [infinite virtual space], and it's quantum based that all means, the universe as a "quanta" is in superposition where all your decisions and measurements are constantly "transporting" you from one parallel reality to another one, you're basically browsing parallel realities based on your decisions since the universe is in all states at once

[@frozenlettuce653]

"So you want to grant?" "Yes" "Well, I really wanto to give you, but I can't. Maybe in another universe!"

[@S.aTan-._.-]

Shout out to all the unemployed still in bed

[@monochromatech]

My brother. I found you.

[@zkeletonz001]

Wooohooo!

[@robscoggins]

I’m retired. Does that still count? 😂

[@amihartz]

I am the employed still in bed.

[@UglyFaceOnAStick-iz8bt]

I'm employed, but still in bed.

[@AisleEpe-oz8kf]

Thank you. You have a finely honed sense of awareness. As a body sense aren't you bound to the quantum world? They seem to work together pretty well. Thanks again.

[@brendangolledge8312]

I thought a measurement was any interaction with a macroscopic body. In other words, any time a quantum particle is forced to interact, the wave function collapses. I was taught in my quantum mechanics course that when you have many particles together, there are overlapping parts of the wave function, and that these parts tend to cancel each other out, increasingly so when there are a large number of particles. Thus the state of an individual particle is uncertain, but the uncertainty in a macroscopic object as a whole becomes vanishingly small due to the large number of particles.

[@lepidoptera9337]

A measurement is an irreversible energy exchange. It does not have to be a macroscopic body that captures this energy. Even the loss of energy towards infinity (e.g. escaping electromagnetic radiation) is "a measurement". Technically that's the only measurement we need in quantum field theory (outgoing plane waves) but since we are impatient we usually put a thick piece of matter in the way of that outgoing radiation and we give it a fancy name like "detector". :-)

[@GadZookz]

People who truly believe reality doesn’t exist need to be observed by real people 24/7.

[@ScottJPowers]

quantum mechanics just gives you a range of possibilities given a lack of information. when you provide the rest of the information, it gives you a definite answer. This doesn't reflect the real world, however. just because you don't know something for sure doesn't mean that part of reality must be in some kind of quasi-limbo state, or do you all think that the world is an imagination of yours?

[@Rudxain]

There's a branch of philosophy that believes nothing is real except the self

[@wb3904]

No quantum mechanics through the Heisenberg uncertainty principle says that it is impossible to know anything definitively. You can know the position or momentum of a particle but you can't know both exactly. So yes reality is in quasi-limbo state, something Einstein didn't like.

[@ScottJPowers]

@@wb3904 no. you can't know momentum and position at the same time because those two measurements are mutually exclusive. a position is 1 exact point in space but to measure momentum you need to know the difference in time when the particle was in at least 2 different positions at different times to measure velocity/acceleration. You'd need a third point of reference to know in what direction it is traveling. so, you can't say how fast something is moving or in what direction with only 1 point. Likewise, you can't say exactly where something is when traveling at a certain speed and/or a certain direction.

[@wb3904]

@@ScottJPowers that's what I said lol. Read it again 😇 Also it's not mutually exclusive, it's only that you can never get a full picture. It's like looking at a cube, you can only ever see 4 of the 6 sides.

[@hal5189]

What I learned is, QM is not (as yet) the science of how the world works, but of what an observer can tell. By definition, "superposition" = "the observer knows that he doesn't know" and "collapse" = "the observer learns". That kicks out philosophy except "objective reality", and leaves scientific issues like "WTF is going on?". Except nobody seems to agree with this nowadays. Is there a reason it doesn't work?

[@alexandrascherer5463]

On a molecular scale nothing is "flat" or "classical". "A measurement" is giving any degree of freedom extra energy to transform into another stable state - often returning to groundstate if possible under emission of something (concerning either vibration, rotation or by just mechanically stopping translation). There is no magic and nothing is at two places at "a" time (although the probability for two places is the same). It might be "at two places" within "a measurable time Intervall though".

[@BenjaminCronce]

My natural assumption about quantum vs classical is that a set of entangled particles are themselves a measurement device and every time they interact with another set of participles, and become entangled, the entanglement causes the two previously independent quantum systems to become a single system. But there are ways to isolate particles into separate quantum systems, which is constantly happening, creating some amount of randomness. And what constitutes a system may be more of a continuum.

[@aaronjennings8385]

The double slit experiment seems like an example of a many worlds.

[@wb3904]

No it shows that everything is a wave. If anything the collapse of waves into particles could be the spawning point of a new world.

[@StylishHobo]

Many Worlds has always felt like fantasy rather than science. It's like a clumsy explanation a child would come up with.

[@yeroca]

And yet some still feel that it is an inescapable conclusion. To me it doesn't follow Occam's Razor, but that isn't a good enough reason to reject the idea entirely. Maybe what these scientists are arguing is that the lack of a solution to the measurement problem is in fact a falsification of the idea of measurement at all, and that therefore the Copenhagen interpretation is ruled out. Perhaps this is just a false choice in favor of the many worlds interpretation. That said, I haven't attempted to read the paper.

[@SabineHossenfelder]

Does it really explain anything?

[@Blokilicious]

It is the most sophisticated explanation for quantumn effects we have. It's simplicity lends weight to this. You really think our specific reality is the only form existence takes?

[@Christian-gc6nn]

”It feels like fantasy” can also be said of many other strange things in science that has later been verified or proven false. Not saying many world is true but we shouldn’t rule it out for its strangeness.

[@NoNameAtAll2]

question is whether it's more clumpsy than alternatives and "quantum wave just magically decides where particle is" is just as obscene

[@michaelsherck5099]

The clarity of your explanations is enhanced by your sense of humor. Neither are expected of physicists with advanced degrees. If you did not exist it would be necessary to create you. 😉

[@thesenamesaretaken]

This puts me in mind of a differential equation whose general solution is a linear sum of different terms, one of which diverges at a physical position (typically at the origin). The standard approach is to set its coefficient to zero as it is non-physical and leave it there. Now I see that the divergent term exists in another universe.

[@lotsofstuff9645]

The “Many Worlds” interpretation feels a lot like a god argument. It just explains everything and at the same time explains nothing with an incredibly overly complex solution.

[@valrond]

Yep. That's what happens when science stops being science and becomes a religion. I

[@philiphumphrey1548]

Doesn't really make any unique predictions that we can test, either.

[@lionelmessisburner7393]

It’s not like creationism at all lol

[@marsovac]

I agree with the first part, but the solution is not overly complex. It is in fact the simplest solution possible. It makes exactly zero assumptions on the shroedinger equation. Something that you feel not satisfying does not make it overly complex. It just states "all outcomes to a measurement do exist". There are currently no simpler interpretations of QM, and perhaps can never be.

[@firelordplayz]

It's actually nothing like it lol.

[@ibonkoteron6779]

I love your precise understanding of the philosophical problem of postulating as many realities as possibilities because maths only cannot distinguish among them!

[@Unmannedair]

I thought that classical was the limit of quantum once you understand that noise approaches the central limit? This is kind of like the definition of annealing an entangled system.

[@stephenpuryear]

Sabine, I "feel" that you are still on the right track, knowing that I have no independant apparatus that produces a result to verify my feeling. Keep it up, stinky feet and all!

[@guest_informant]

I'm a Many Worlds fanatic. It seems to make total sense to me but it's a long way from any area of expertise I might have. I'd really like to hear Sabine debate this with Sean Carroll for instance - and hope that I could follow along.

[@MrSpikegee]

Me too, bro, me too.

[@oneeyejack2]

there's two way in my mind that works to resolve the problem : - particle aren't wave like at all, but the void is packed with particle as half of them go back in time and perfectly cancels those who go forward.. so the sum of all this looks like QM statistically - particle are some sort of blob with a limited extension in the past and in multiple futurs.. so they slowly select between many worlds but some branch die constantly.. that way the number of alternate realities is a constant and what we call decoherence is the last common ancestor the current various realities.. If you suppose there's a limit in alternate reality volume.. a measurement apparatus is a system that cause a quantum property to have macroscopic consequences... meaning "alternate values of a properties" cause "alternate macro group of particle to be different"... And in that case, it's easy to see that the value we observe could be the "last common ancestor" of alternate values of the property. If alternate values are link in space time in a tree way.. there can be relative to the observer multiple values each moment AND a single value of the past.. A TREE OF VALUES OF CONSTANT WIDTH (in the dimension of alternates obviously!!) ALLOW FOR REALITY TO BE BLURED NOW and the PAST to be UNIQUE (the last ancestors of alternate realities). I've been screaming this for years and nobody listen.

[@leandrof.laurito887]

Hello from Brazil, i really like to watch your videos. :)

[@glassworktrophic8465]

This all goes over my head, but can it not be that each particle in the universe is actively measuring it's neighbors? It always seemed to me that we imbue life with too much credit as the "observer". Maybe the universe observes itself.

[@absalomdraconis]

It's all a "game" of billiards. Admittedly, it's not necessarily played with sphetes.

[@theslay66]

An "observer" doesn't need to be something alive. It can be any measurement tool.

[@blinkingmanchannel]

Sorry for an unrelated (or at least distantly related question): The link at bottom points to work being done in Bonn. It’s cellular imaging with machine learning. On one hand, I think it shows we are still too far from the molecules to see what is going on with electrons, but it’s close. On the other hand, it seems to go in the right direction. Thirdly, this reminds me of your video about academia and I’m wondering of something is changing. This feels like “tech bro” meets “grant writing software” and hires desperate post docs. Like an academic startup…? …what??? Link: kzbin.info/www/bejne/nKnKaGShi6t5hZYsi=rQdnUiQlGk2jQPRw

[@RegHoldsworth-ri7hh]

Excellent as always sabine, have you ever done stand up? It's thought if this science thing doesn't work out.

[@prischm5462]

You make very good points about reality. One of my pet peeves is when I hear some scientists say that the direction (or arrow) of time is an illusion. The have the hubris to say this because their sub-atomic particle equations don't show it. However in my world (and theirs) time definitely has a direction. We could not live our lives without constantly taking it into account. Without it we are lost.

[@rxbracho]

You answered the question to the "riddle" when you said that the classical world doesn't come out of the MATH. Dear physicists: you must remember that math is a tool to understand what manifests in reality, which is what you are supposed to study. There is nothing magical about quantum mechanics but it doesn't talk about manifestation in reality UNTIL a whole is created, the smallest of which is an entangled pair (thus the emphasis on "observation"). Keep on playing with math if you care, just don't confuse it with reality.

[@simonpayne7994]

Sabine at her very best!

[@Nostrudoomus]

Oh, here chew on this! The other day I saw somebody said matter is light frozen 🥶. I thought 💭 no not a very good metaphor. If light is as fast as energy gets then it is a type of pure energy and it displays that by traveling in a perfectly straight line. So all forms of matter, IS ENERGY, but does not travel straight, instead it spins into itself and that explains why electrons find other fundamental mater and then spin around it. This explains ALL forms of energy less dense than light and the frequencies on the electromagnetic spectrum above light. And different types of spins and combinations of spin form everything in the quantum world other than light 💡 and the higher frequencies. And then this got me to thinking everything could be shrinking constantly at the quantum level up into the macro and that is what keeps it all moving, in the quantum, energy is directly consumed resulting in shrinkage of energy/EVERYTHING. Such a CRAZY IDEA that would explain a very rapidly seemingly expanding universe with red shift everywhere but really isn’t expanding, at least not super fast, but is really just shrinking very rapidly!😮 And this would very well explain why when they opened up the hermetically sealed metric system standards and measured them, THEY WERE THE WRONG SIZE!😮 Holy cow, then I started to remember how dinosaurs 🦖 and their fossils get larger the further back you go and the gigantism scientists observe in species in the past! Maybe not EVERYTHING shrinks uniformly maybe fossils shrink more slowly than everything else because they are a denser material to start with!?😢 Makes sense! So animals were all larger in the past than today because since long ago everything has shrunk a lot but the fossils shrunk less because they are more dense. If that is correct then dinosaurs were just little lizards 🦎 back then!😮 And then I started seeing all the ancient rock formations that looks like tree stumps that have been so UNIFORMLY CUT ON TOP, CRYSTALLINE MINERAL STRUCTURE CAN NOT EXPLAIN ALL OF THEM!😮 If matter can shrink that much then it guarantees that black holes 🕳️ will NEVER stop shrinking in the dense matter internally, again guaranteeing that the dense matter will NOT be uniform and have some areas much more dense than other! This then coincides with the, UNEVEN EXPANSION OF OUR UNIVERSE, meaning that we ARE inside a black hole 🕳️ and there was NO BIG BANG rather an empty space simply opened up because of the uneven contraction of the matter with the black hole 🕳️ our universe is in !!!!!! 😨😳😱😲😵‍💫

[@linuslundquist3501]

What does frozen mean in this case?

[@kxqe]

0:55 Actually a table is spread out in space and is in many places at once. If you cut the table into two pieces, they are entangled -- if you measure one piece, you know some of the properties of the other. However if you wait long enough, the table pieces will decohere into their constituent molecules and atoms and they will no long be entangled. Understanding QM from a classical perspective makes sense to me.

[@CezarJenkins]

The top-level measurement apparatus is the program running the simulation of our universe. It recursively resolves the probabilities of the system as it calculates the interactions. The speed of causation (light) is an optimization to allow for the parallelization of the simulation on to multiple nodes. Why could inflation happen so quickly and then grind to a slower expansion? Because the calculations for inflation were much more homogeneous and therefore quicker. As expansion continues and removes large sections of the universe beyond the horizon of causation it allows for more parallelization of the calculations without inter-node communication.