Four Types of Multiverse - Sixty Symbols

[@likeriver]

Sixty Symbols should explain more physics ideas using Ed Copeland analogies.

[@Kavetrol]

Any universe without Ed Copeland is rubbish.

[@sixthSigmaSnowball]

+likeriver Edcopelatonic Field Theory, conformally smooth, yet nicely peaty.

[@taba1950]

I agree, he is so calm I envy him

[@quinishawoodswoods9132]

e

[@aliceainsley]

like like like like like like like

[@Farrisfaen]

"Are you alright darling?" "I'm being maintained annoyed in some regions of space" "oh"

[@MichaelFoleyPhotography]

Quote from the Wikipedia article on the Mathematical Universe hypothesis: "in those worlds complex enough to contain self-aware substructures they will subjectively perceive themselves as existing in a physically 'real' world" This absolutely blew my mind.

[@Raxilla]

+Michael Foley Just think of how infinitely up that chain complex math can go? And that we're way at the bottom of it.

[@WMPEXFBTLZYH]

Are all humans Boltzmann brains?

[@stephencampbell2735]

Will they not be existing in a real, or real enough, world?

[@piccalillipit9211]

The universe exists because we perceive it to do so...

[@piccalillipit9211]

@Toughen Up, Fluffy - Yep - you navigate the data streams of the universe in a 3D world created by your consciousness to make it easier - and there is nothing to say your dog perceives ti the same as you do - it may have an entirely different model. As long as that model allows your dog to navigate the date - it works.

[@davidkimlive]

Multiverse playlist only contains videos from our universe. Unsubscribe.

[@kappesante]

well played

[@Mekratrig]

+davidkimlive Much disillusion; very disappoint.

[@nathanmann9135]

The playlist contains videos from every possible universe, but you're only able to perceive the videos from your universe.

[@WMPEXFBTLZYH]

I need Memes from the &$+#;@² Universe!

[@MobiusCoin]

Can Numberphile do a video on different types of mathematical structures? I think I get what the level 4 means, but I'm not quite sure. It would be helpful if you guys can expand on that a bit. Also, can you guys do a video on decoherence? That would be really interesting as well, thanks a bunch.

[@GarethField]

ViHart did a great video on sets and types of infinity that would be a great place to start if you're interested

[@MobiusCoin]

Gareth Field I remember that video. I'm particularly interested in this structure that doesn't have multiplication and how that would manifest into something physical.

[@googelplussucksys5889]

A decoherence video would be great but mathematical multiverses seems a bit specific for an entire video.

[@coreylevinson7339]

Here's what I think he means by it. Let's say we know that F = ma holds true for our universe. If we believe in the level 4 theory, then we will state there exist universes where F = m + a holds true, F = m / a holds true, F = m - a holds true, F = m^2 - 3 + a! holds true...an infinite amount of universes that hold an infinite amount of different mathematical equations. Some of them may not exist (for example, if we say F = m/a, what happens when an object isn't accelerating?), some might exist in ways we don't recognize.

[@BlueCosmology]

Corey Levinson Not completely true, there can be an infinite number of different equations to describe them differently, but they would still need to be internally consistent. For instance all the things you've wrote there, none could be true as they are not dimensionally consistent - basically they are just meaningless. Since none of them are dimensionally consistent, none of them have any answer. The answer you get out completely depends on your choice of units.

[@rightwraith]

Right when he said "Well they're right on top of each other but there's no way to communicate between them" audio from another browser tab started playing in my headphones at the same time as him talking and my mind exploded

[@DustinRodriguez1_0]

I listened to an audiobook a few years ago that mentioned something that I've not heard mentioned elsewhere. The idea was that the Pauli Exclusion Principle means that if the universe is above a certain size that every possible combination of quantum states would be present, and the exclusion principle would mean that the universe would have to begin to repeat. It was an interesting idea, and I'd really like to hear more about it.

[@freshofftheufo]

Fantastic video Brady and fantastic explanations! What a great teacher. The amount of silly speculation on multiverses on the webs has been ridiculous lately, now I finally have a solid starting point to bring the discussion back to reality! Once again proving why you're one of the best producers on KZbin. Keep up the good work :)

[@Carefaceeeee]

I like the forth type. Radical thinking is the only thing thats gonna take us forward from this point.

[@topguntk870]

level 4 are in there own continuum. according to max tegmark the level 4 multiverse dont exist in spacetime but spacetime exists (the universes that have space and time instead of other unique math or equations) in them. so they exist in a completely different physically really reality. its hard to imagine. those realities have the right to be called universes of there own. even though nothing there will never effect whats happening here and vice versa. but they are physically out there. they could look like anything you can imagine and even cant imagine. my brain really hurts trying to imagine level 4 multiverses but whichever universes in the level 4 multiverse can have self aware entities they are just as real as we are. according to tegmark also theres literally no way of ever comprehending or knowing if such a mathematial set of physically real realms is possible or real as like i said there nothing from there or here can effect each other no matter how godlike one can become. its almost as if they are real but at the same time not real for us and for them ours isnt real either. but they exist physically somehow somewhere but its almost a paradox. because the level 4 dont exist in a space but in a hypothetical unreachable existent containing our reality that contains space with other realities and universes that perhaps dont have space or time but wholly alien concepts and colors and rules and nature.

[@JuriRadov]

I think of the Many World hypothesis as follows: There is just one universe at a time, andeach instance wouldn't manifest itself immediatly but over time. When this universe is dying (it doesn't matter if big bounce, heat death, big rip or any other) all the fundamental blocks would be shuffled and a new universe with new properties and/or outcomes will be formed. I'm thinking of the microwave backgroudn radiation of a unique fingerprint and in this prior described scenario we will have a new fingerprint. Over time and probability every possible outcome could manifest by itself and we're just lucky to life right now in this universe with this specific fingerprint. The next universer will have a new fingerprint and a certain cointoss will be tails instead of heads and nothing else changes. In general i just think, there is no need for more than one universe when thinking about repeating itself indefinetifly with always new properties.

[@OOspazOO]

It's certainly a far more coherent theory than anything talked about in this video.

[@sweet77creepy]

About that 'seeing circles in the sky ' thing... it seems strange, coz if it is an actual contact between two universes, then what set of definitions are we using to distinguish them as 'different' ? If they can meet, they have a common interface of space and hence they are essentially a part of the same physics domain. Also, during impact, don't they influence or interact with each other?

[@topguntk870]

not level 4. level 4 are in there own continuum. according to max tegmark the level 4 multiverse dont exist in spacetime but spacetime exists (the universes that have space and time instead of other unique math or equations) in them. so they exist in a completely different physically really reality. its hard to imagine. those realities have the right to be called universes of there own. even though nothing there will never effect whats happening here and vice versa. but they are physically out there. they could look like anything you can imagine and even cant imagine. my brain really hurts trying to imagine level 4 multiverses but whichever universes in the level 4 multiverse can have self aware entities they are just as real as we are. according to tegmark also theres literally no way of ever comprehending or knowing if such a mathematial set of physically real realms is possible or real as like i said there nothing from there or here can effect each other no matter how godlike one can become. its almost as if they are real but at the same time not real for us and for them ours isnt real either. but they exist physically somehow somewhere but its almost a paradox. because the level 4 dont exist in a space but in a hypothetical unreachable existent containing our reality that contains space with other realities and universes that perhaps dont have space or time but wholly alien concepts and colors and rules and nature.

[@LaMaisondeCasaHouse]

Thumbs up not only because all Sixty Symbols videos are great, but in particular because Dr Padilla actually uses the word "Ginormous"!

[@topguntk870]

level 4 are in there own continuum. according to max tegmark the level 4 multiverse dont exist in spacetime but spacetime exists (the universes that have space and time instead of other unique math or equations) in them. so they exist in a completely different physically really reality. its hard to imagine. those realities have the right to be called universes of there own. even though nothing there will never effect whats happening here and vice versa. but they are physically out there. they could look like anything you can imagine and even cant imagine. my brain really hurts trying to imagine level 4 multiverses but whichever universes in the level 4 multiverse can have self aware entities they are just as real as we are. according to tegmark also theres literally no way of ever comprehending or knowing if such a mathematial set of physically real realms is possible or real as like i said there nothing from there or here can effect each other no matter how godlike one can become. its almost as if they are real but at the same time not real for us and for them ours isnt real either. but they exist physically somehow somewhere but its almost a paradox. because the level 4 dont exist in a space but in a hypothetical unreachable existent containing our reality that contains space with other realities and universes that perhaps dont have space or time but wholly alien concepts and colors and rules and nature.

[@gves2]

Haven't seen Dr Tony in awhile. Thanks for the video and keep going! It's great to see theory and it makes everyone better for seeing these types of videos. Thank you!!!

[@ibbyyoutube]

This video isn’t loading for me :(

[@shaeuwn]

same, i wonder why

[@ryanking2155]

Working again, guys. Had the same problems myself for months :(

[@GuruGodPlays]

@10:12 The splits occur at all times. It's why the many worlds theory is so fascinating, because literally every moment is an infinity of possible moments coming into existence.

[@sweet77creepy]

Can someone tell me what exactly is in between the parallel universes in the second level? It is obviously not space..do we have a clear understanding of the all pervading medium ?

[@ThePinkus]

There is no pervading medium implied. The great realization (think Gauss & Reimann, and all the differential geometry/absolute calculus mathematics) is that geometry (as metric, as extension) is intrinsic, and You don't need to embed it in something else, such as a pervading medium, to think and completely describe it. "Parallel" in "parallel universes" might be misleading.

[@adampartridge1903]

Could it be possible for there to be a universe in which maths doesn't exist at all, as in there is no such thing as quantities (like numbers) or operations to do to quantities (like addition, subtraction, etc...)? What about a universe with no space and no time, and it just operates in a completely different way that's entirely separate from dimensions. Maybe an extremely simplistic universe, where there's just this one eternal state? All I seem to be able to see when I try to picture this, is a universe where there's just one solid colour, that's always there, except not really because a term like "always" is irrelevant because time doesn't exist. Obviously the concept of colour couldn't possibly exist in such a universe, because colour requires light and everything. but that's the only thing left that my mind seems to be able to picture, when things like space, and therefore shapes, are taken away. Human language is very restrictive when it comes to this kind of thing because it's evolved only needing to describe how things are in this universe, with our laws of physics. What about a universe that's not so different to ours, where space and motion and things are allowed, and say maths works in the same way, but when it comes to physics, different mathematical formulae govern things? Suppose F=m/a in this universe instead of F=ma, as I believe someone else in this comment section said. How would that work? The way that motion behaves in this universe would have to coherently conform to that formula no matter what, in much the same way as motion in this universe always conforms to F=ma, and I try to picture how that would work but I just can't.

[@blackkittyfreak]

You should do a video on Boltzmann Brains.

[@djvelocity]

That would be amazing 🤩📚 you really should do this. Such a fascinating subject for your audience 😊🙌

[@FirefoxisredExplorerisblueGoog]

If the 4th level "physically exists" doesn't that mean that it's testable? Or is the term "physical" used in a different way here? I could say that the moon physically exists because astronauts landed on it. Similarly, could I say mathematical universes physically exist because we it? Another great video on the subject, I'm loving these.

[@topguntk870]

they mean it really exists out there. in real and material form just like how our universe is. stop making it harder for yourself. if you want ill explain

[@topguntk870]

they mean it really exists out there. in real and material form just like how our universe is. stop making it harder for yourself. if you want ill explain

[@bgbong0]

So does this mean that somewhere in a level 4 multiverse, Bitcoins might be physical entities?

[@saldownik]

Aren't they in our? They are just a bit distributed.

[@gabetower]

One interesting point Max Tegmark mentioned in his book when talking about L3 multiverse is that if the universe is infinite (or even just colossally huge) a level 3 multiverse can be interchangable with a level 1 multiverse. So in a L3, from each point, you have all possible quantum states that become a reality. In a L1 multiverse, assuming it's again, infinite-ish, the combinations of matter will repeat themselves in such a way that there is another pocket universe where those alternate universes DO exist. Not necessarily as a direct result of causality from your current point of view, but none the less just as real.

[@itsjustameme]

Level 5: They could all be true. Or would that be included in level 4? Come to think of it that is probably the case...

[@davecrupel2817]

That would be included in lvl 4. 4 basically covers everything that isnt 1 2 or 3. Including.... *VIDEO GAMES!!* _dramatic music_

[@genoshuynh9143]

Level 5 is extended modal realism which is essentially contains anything that is possible and impossible things like paradoxes

[@ericsbuds]

Awesome video guys!! Great topic and even better explanation.

[@NNOTM]

I can't help but feel like Dr Padilla doesn't quite understand what the Many-Worlds interpretation really means. And to be fair, I very well may not either, and I'll admit that Dr Padilla knows several orders of magnitude more about physics than I do. But I did want to clarify a few things, as I understand them: One "world" refers to a "blob" of the wavefunction where the amplitude is greater than zero (and therefore, according to Born's rule, the probability of finding ourselves there is greater than zero). Two worlds would refer to two seperate such blobs. There is no need to have a specific moment in time at which two worlds split. To understand this, it may help to look at a function over the real numbers: Imagine a function g(n)(x), which is just a normal distribution with the mean at n. (So it pretty much looks like the blob I referred to). Now we can imagine that the wavefunction at time t is g(t)(x)+g(-t)(x). (I'm not choosing this example to represent anything meaningful, just to see what it would look like when a world splits up.) At time t=0 it would just be a normal distribution, because the two terms in the wavefunction are g(0)(x). But at time t=100 there would be two seperate normal distributions, or blobs, one at x=100 and one at x=-100. There wasn't any specific point t when these two blobs split up. I'm not sure what he means by increasing the size of the state of the quantum system. As far as I know, the evolution of the wave function is unitary, _unless_ you incorporate a collapse postulate which states that all but one point of the wavefunction suddenly goes to zero. Decoherence is, in a way, synonymous with Many-Worlds. Two decoherent "blobs" in the wavefunction correspond to two seperate worlds. This all means that the Many-Worlds interpretation is the natural conclusion one can draw from looking at the wavefunction. Anything else would require to add additional information, which goes against Occam's Razor. Also, every law so far in physics is deterministic, which suggests that it's likely that physical laws in general are deterministic.

[@HebaruSan]

Yeah. It's like any other interpretation, minus the "then magic happens" step.

[@Ni999]

Occam's Razor is not a scientific principle, law, or rule of any kind. Laws are deterministic because they're placeholders for things we've observed but of which we have no elaborate understanding.

[@ericgorlin]

@@Ni999 Actually, it kind of is. Why do we believe that gravity is 9.8 m/s^2 instead of 9.8 m/s^2 most of the time and 4.2 m/s^2 in the year 3069? These theories fit the data equally well. But when you have two theories which equally fit observed data, you should choose the least complex option. Adding on an unnecessary additional clause, like "gravity is different in 3069" or "the wavefunction collapses when you look at it" makes your theory worse.

[@Ni999]

@@ericgorlin I suspect that your belief about the acceleration due to gravity in the year 3069 is driven by the possibility that you're stoned, an idiot, or both. Feel free to reply when neither condition applies and not sooner. And the choice is for the explanation that does not violate other observations when there's a tie. Your opinion, fortunately, has nothing to do with how science works.

[@ericgorlin]

@@Ni999 Huh? I don't actually think gravity works that way, I was using a metaphor... And as far as I know, current observational evidence doesn't let us distinguish between collapse theories and many-worlds. We need to use other reasoning to decide what's better. And in this case it's pretty easy - many-worlds is simpler & more elegant (one equation instead of two) and doesn't violate special relativity (collapse + entanglement = faster than lightspeed spooky action at a distance)

[@saltwt2735]

The reason I like many worlds is it explains quantum superpositioning and waveform collapse of a particle as it entangling itself with our universe creating many with different positions in different universes or whatnot

[@Berelore]

3 Doesn't need to create a whole universe for every collapse that's just a convenient way to think about it. I always pictured that every possible universe was created all at once and every time you have what we call a collapse one of the infinite number of them diverge from the rest of the pack that are still in sync. So still probabilistic but accounting for every probability being played out somewhere without some magic universe spawning every time you flip a coin.

[@Berelore]

Perhaps I failed to describe it adequately, but neither causality nor information flow are violated in this framework.

[@drew2pac]

You know, whenever I think about the infinite or finite nature of the universe - it truly blows my mind! Just he scale of it, the strange phenomena (from large scale, right down to quantum), the fact there could be multiple realities. Seriously, when you stop and think about it, it is enough to make you dizzy

[@E.lectricityNorth]

All good science should make you dizzy, without actually accomplishing anything. It's the only true mark of good science.

[@RasterGraph]

I know what you mean. Given the overall flat nature of space and the possibility of Eternal Inflation. It boggles my mind to think that somewhere, out there, is another me typing this exact same message and having the exact same thoughts.

[@jmitterii2]

Its huge.

[@MrMhornberger]

drew2pac "the fact there could be multiple realities. " I think it's just one reality, but that reality is much bigger than we thought. We already knew there was more out there than we could see. The whole history of science/astronomy/cosmology is one long story of us learning, time after time, that the world was bigger than we thought. The multiverse and inflationary model just represent the latest iteration of that trend.

[@samuelkuhn4067]

Level 4 multiverse makes my imagination go wild.

[@nmarbletoe8210]

yeah that's a very cool thought

[@davecrupel2817]

Its like psychological crack :D

[@CaptainPilipinas]

right, and these 'type 4s' are just that effortlessly back within a single main [Flower Game] verses of Destiny. [mumbled yawning]

[@topguntk870]

tegmark himself said level 4 multiverses exist outside of space and time. and that any universes that have self aware observers will feel they exist in a equally real universe. this blew my mind like nuts. all the rules are out the window in the level 4 multiverse. any universe you can imagine truly exists physically somewhere. that is scary and fascinating. they would exist beyond any of the other levels. tegmark stated they dont exist in space and time but space and time exists in (some) of them. anything natural or supernatural that is possible exists. most of these level 4 universes logic and ideas wouldnt make sense to us. and ours wouldnt make sense to them.

[@barnowl2832]

Love the "maths is reality" theory, the one thing that permeates all the universes. So someone in a different universe could study the maths of our universe, see that it checks out and think "damn that'd be weird"

[@TheMilkManCow]

Don't fuck with Ed

[@Loop44]

Level 2: bubble within a bubble due to different constant values, the expansion of the inner bubble does not necessarily imply the expansion of the outer bubble. the inner bubble can expand and it's total interior volume becomes greater than it's exterior volume so it continues to occupy the same space in the exterior bubble which remains unchanged in both interior and exterior volume.

[@topguntk870]

Level 5 Multiverse: Multiverse that doesn't have any math or physics but runs on something completely unknown to us. Alien concepts, logic and types of things..

[@djudjuy]

Very well explained Dr. Padilla.

[@Chrisallengallery]

I like the theory of a fractal universe. One where there is a universe inside every black hole. With black holes inside the universe that's inside a black hole. It could go on forever. In a singularity there is no time any space but a portal into the next universe. That could be the theoretical wall.

[@unvergebeneid]

Yeah, locality is boring. Bring on fractal objects that are coherent just through the function that defines them.

[@Chrisallengallery]

Mikko Finell There is no first...or last.

[@tomasfernandez9045]

The problem i have with that is that you have to assume that other universes have black holes in them.

[@chickenj90]

Mikko Finell From what you say numbers cannot be infinite as if a starting point doesn't exist then none exist and that is just incorrect.

[@aakksshhaayy]

Dan M You should rely more on peer-reviewed articles than some random website.

[@auto_ego]

I'm really looking forward to advances in research on Ed Theory.

[@sixthSigmaSnowball]

If Tegmark can prove that reality is Godel complete, I'll accept his walking off the firmament of physics and grasping onto a stairway to the Platonic ideal.

[@mahnamesjakers]

one of their best videos

[@ragnkja]

Is Dr Padilla using Professor Copeland as an example just to rile him up? =p

[@yvesnyfelerph.d.8297]

...basically he is saying that the universe was created when ed copeland lost it at some point in the distant past?

[@davecrupel2817]

2:30

[@trahlem]

amazing... and amazingly explained by Dr Padilla!

[@mattsmith8160]

Last I heard there are five types and what he describes as level fours are what I've heard described as level fives and the real level fours that he skipped over are called Daughter Universes. These daughter universes explain away the grandfather paradox. Basically there's a different universe for every possible outcome of every event. Imagine Schrodinger's cat. After you open the box a new daughter universe is created so there's a universe where the cat is dead and one where it's alive. So if you go back in time to kill your own grandfather, once you arrive in the past you instantly create a new daughter universe since you didn't exist in the past of your original universe so you can kill your grandfather in that daughter universe without threatening your own existence because in the past of your original universe your grandfather is still alive and well. The catch is you may never be able to get back to your original universe even if you travel forward in time again you'd likely just wind up in the future of the new daughter universe you created by going back in time in the first place.

[@WhiteChocolate74]

Seems similar to parallel worlds theory in quantum mechanics

Question: Would it theoretically be possible to measure the gravitational force on an object near the border of the observable universe that it gets from an object outside of the observable universe?

[@eveeeon341]

I have my own hypothesis for a multiverse. First of all, considering the notion of higher dimensions, we have no experience of them and so could not have a clue what or how they are, we can however look at the dimensions we do have, and work up from 1D to 2D and so on such that we can repeat the difference for higher dimensions. From 1D to 2D you find that 2D can be described as an infinite amount of 1 dimensions put together in a dimension- so you have the same dimension over and over, each varying from the others, being further on in the new dimension, the same goes for 2D to 3D. Also the two dimensions in 2D are exactly the same, in fact the only difference is perspective. Now let's apply this to 3D, we have an infinite amount of 3 dimensions put together, varying across the new dimension, this actually describes time pretty well, however, from our perspective, we only experience 1 position of "time", whereas we can experience multiple in the lower 3 dimensions, hence the differences. Although, from before, going along with this hypothesis, we also have that "time" is exactly the same as distance, it's just a matter of perspective. Anyway, we now have 4D, a "line" of an infinite amount of 3 dimensions, containing all variations of those 3 dimensions, lets do it one more, now we have a plane of these infinite amount of dimensions in 5D, an infinite amount of "variations in the timeline" so these would be alternative universes. Now let me clarify that when I say variation, a different arrangement of particles. Anyway you could continue to do this, I loose all grasp of what I'm trying to comprehend at 7 dimensions though if I'm honest. However the point that all dimensions are the same and perspective is the only thing that makes them seem different is the idea, this would also mean particles can travel through the dimensions, and that could be a good explanation for quantum probabilities- there will be structures across the higher dimensions because forces in this dimension (and others) attract particles, meaning cross dimensional structures would compliment the structures within the dimensions and vice versa so it wouldn't interfere with the mechanics we know in our 3 dimensions (and a half- time). Let me also say that I'm not saying that the 4th dimension is time, or that time is like distance, but however, the 4th dimension we experience (they're all arbitrarily similar) that is exactly the same as distance is experienced by us as time, and if we somehow changed our perspectives through dimensions, we could walk through what we call time. Also since we move with respect to a dimension that we only exist at one point on, the notion of motion is meaningless when looking at all the dimensions, and really everything is more of a multidimensional image- we experience movement because the particle arrangement at each later point of the "4th" dimension is such a way that our brains contain memories from the previous points. But I'm not saying we're not moving, just that moving is unique to particular perspectives of dimensions. Sorry for the long ramble- I had so much to say and it's hard to put this kind of thought into a youtube comment and it didn't quite turn into a particularly great explanation, it's only an idea I've thought up which I think is at least self consistent and would make sense with what we see in our universe. I'm not sure anyone will read it though ._.

[@E.lectricityNorth]

I'm not sure either.

[@googelplussucksys5889]

I tried... and failed.

[@E.lectricityNorth]

***** Ok, that is a simpler way of looking at it, perhaps. Is anyone reminded of how a circle is an infinite number of infinitely small angles joined together, or am I just up too late?

[@Neueregel]

cool story

[@ObeseYeti]

***** That's what it started out as, except it turns out you can't have non-zero infinitesimals in the real number system. Calculus is now more commonly defined using limits, the 'dx' can simply be seen as notation.

[@googelplussucksys5889]

9:20 Correction, according Max Tegmark’s Many Worlds in Context a split doesn’t occur at the time of an event as described in this video. According to him I believe all many-worlds configurations have existed since always similar to how I also believe common scientific consensus holds that spacetime exists as a static eternal infinite Minkowski spacetime or whatever the appropriate description is so an event wouldn’t actually cause this controversial mysterious explosive birth of multiverses which many have issues with. Others may disagree though.

[@aliceainsley]

everytime i watch this video i get more curious about what Prof. Copeland is like when he''s angry

[@mrspidey80]

You wouldn't like him when he's angry.

[@cdas6673]

I'd really love to see arguments for each of these theories. It seems (without seeing any arguments) that choosing to believe one or the other is just arbitrary. I really hope to see an expansion on this video!

[@xxhellspawnedxx]

I have a problem with the type 4 multiverse. It just seems like navelgazing, to me. Mathematics isn't a component of reality, but a way, a language, to describe it. A language that we have invented. If that language had indeed concluded that one plus one equals three, or "scrubbeildupe", or "licorice wrinkle", it would still just be subjective descriptions of a constant. Isn't it the same thing with other realities? In one of these universes, even if one plus one can seem to equal three, from our point of view and lingual context, isn't that is just a failure of ours to detach ourselves from our own universe, from our own circumstances?

[@snkline]

It isn't quite the as crazy as it seems. The reason a physicist would come up with this idea is that, at a fundamental level, everything that is not mathematics is stripped away from our description of reality. What is an electron? It is a bunch of numbers. What is spacetime? A bunch of numbers. Etc...etc.... Physicists do not find anything in the fundamental nature of reality that is non-mathematical, suggesting that the universe is simply equivalent to a mathematical structure. Now I don't agree with the Type 4 multiverse, but I just want to give you an idea of why Tegmark came up with the idea. For a possible counterpoint to the idea, I suggest looking into the work of Lee Smolin, particularly his recent book Time Reborn. Mathematical structures are timeless, and Smolin is of the opinion that real time is fundamental to the universe, so his arguments, while not explicitly in opposition to Tegmark's, are ultimately the opposite view.

[@xxhellspawnedxx]

snkline Still sounds like philosophy rather than science, to me. Existential mumbo-jumbo. Nothing really _IS_ math. Math is a language (a very exact language, but still a language) developed to describe something, how it looks and how it works... But that doesn't equate it being that thing. It sounds as odd to me as someone stating that a book about the universe is in fact the universe, or that because a treatise on the universe written in English, that means that the universe really is the language English.

[@xxhellspawnedxx]

I concede the point that mathematics is universal, it's the most accurate tool there is to describing the physical universe. But it isn't less of a descriptive, rather than constitutive, matter, than English is. Or, to put it plainly: Maths neither controls the universe nor constitutes it - it describes it.

[@xxhellspawnedxx]

I would say so, yes. Math is created to describe the universe in as exact a manner as is possible.

[@jmitterii2]

It's circular argument than just navel gazing.

[@johnnybatafljeska6368]

I like this guy... He managed to ''explain'' something so unfathomable... awesome

[@youramoron8142]

Ah. The observable universe iS ginormous.

[@CynthiaAvishegnath-watch]

Multiverses are possibilities that converge to resolve into a perceived "reality". We live in a multiverse of possibilities. Rather, our existence is projected onto a canvas of multiverses of possibilities.

[@mattlm64]

Quantum mechanics is likely only probabilistic due to the inability of precisely measuring all variables involved, and not due to some true randomness in nature. Randomness has no logic to it, so I am weary of thinking of it as real, therefore I only take deterministic interpretations of quantum mechanics seriously. I recommend Max Tegmark's book. I do like his Mathematical Universe Hypothesis. What he says makes a lot of sense.

[@tobywilson]

What you are preaching is called the hidden variable theory, and there is experimental evidence against it. It really is probabalistic.

[@mattlm64]

No there isn't and that is one of the biggest misunderstandings in physics. Learn the difference between locality and hidden variables.

[@jamesusespivot]

Matthew Mitchell no. Hidden variables have been ruled out too. See veritasiums latest video. Its the one about measuring spins at 120 degree angles

[@googelplussucksys5889]

Well that's your assertion without scientific evidence.

[@mattlm64]

jamesusespivot Evidence for Bell's theorem only rules out locality. If Derek says on one of his videos that it rules out determinism then he is not only ignorant, but he is also unwise. You cannot rule out determinism, because even if things seem random there can always be a process behind it, much like pseudo-random number generators on computers. They seem random but they are not. Unpredictability does *not* imply Randomness.

[@mobilisinmobili74]

Yes, more with Padilla!

[@BatteryAcid1103]

Guys, bare in mind that all of this is theory. Don't go about your day now believing that any one of these IS the way the universe is because the fact of the matter is that it's highly unlikely that we'll ever be able to even attempt to prove these theories. Instead, go about your day understanding that all of these could possibly be the way reality is.

[@HerraTohtori]

No, it's not a theory. Theories are backed by evidence from repeatable experiments or observations of nature, like the theory of relativity or theory of evolution. The ideas about different kinds of multiverses are hypotheses, and even worse, they are at the moment fundamentally non-falsifiable. That makes them rather irrelevant from scientific perspective, until someone figures out some ways to prove them incorrect and then fail to do so.

[@tc225k]

A theory is sciences is very much different than a theory in 'normal' language. A theory is supported by facts and used to explains something, like evolution or gravity.

[@HerraTohtori]

Flatx1 Yes, but in the context of scientific theories specifically, the colloquial or "normal" language is unequivocally incorrect. There are few things as annoying as the phrase "it's just a theory" applied to any properly established scientific theory. If something in science is called a theory, it means a whole lot more than the word "theory" in "normal" language. There's nothing "just" about scientific theories. I'm not opposed at all to the continued use of theory as synonymous to hypothesis in non-science context, but it is quite misleading to try to apply the everyday definition to the rigorous scientific definition of "theory".

[@E.lectricityNorth]

Didn't you mean to say, "barren mind"?

[@tc225k]

E. Lectricity bear in mind?

[@PXKMProductionsGaming]

Is this video broken in some universes? Cause, if so, I live in the one where it won't play.

[@unvergebeneid]

I think a level 4 multiverse is actually the only thing that really makes sense. Everything that can exist, does exist. That, or nothing at all. But since we exist, it has to be the former. *Edit* I just thought about it again and changed my mind. Copied from a comment below: If all of the possible universes are just manifest without any kind of probability distribution attached to them and assuming that it is possible to construct at least a countable number of contradiction-free mathematical systems to any given base set of contradiction-free axioms by just adding stuff, this means that Occam's razor goes right out the window. Since this clearly does not correspond to our observations, it's reasonable to assume that any given universe has a higher probability of having a small set of rules than a large one.

[@marlonivancarranzabarrient787]

proff for God's existance. also iluminaty confirmed

[@unvergebeneid]

Marlon Ivan Carranza Barrientos Also, please trust your spellchecker when it tells you something's wrong.

[@aakksshhaayy]

I also feel this way.

[@ches95ramos]

Penny Lane I think Marlon was just kidding and being sarcastic but idk.

[@GuyWithAnAmazingHat]

Penny Lane It makes sense, but like Dr. Padilla also said, it is fine that not every probability is realised. Not everything that's possible will become possible, unless our universe or the multiverse is truly infinite.

[@ElvenClaw]

Great explanation! Loved it.

[@wimvanrenterghem5725]

Level 4 begs for the questioning of reality. If a universe has faulty mathematics, meaning that it can't exist, does that mean that it doesn't exist? Or has it tried to exist but it failed? How can we know if those universes are real, if our eyes aren't real ;)?

[@kyjo72682]

I think it comes down to the difference between abstract (mathematical) and concrete (physical) objects. My conclusion is that since both types of objects are observable by a human mind -- both types are real. The difference is just in the method of observation - physical objects are observed via senses, abstract objects are observed via imagination/simulation/abstraction which is done internally by our brain.

[@kyjo72682]

To answer your first question, I think that only objects defined by a set of logically consistent statements can exist. For example a car which is simultaneously: 1) painted with a single color 2) painted red 3) painted blue -- cannot exist, anywhere. This goes for simple objects as well as for entire "parallel universes". Basically you define a parallel universe with a (potentially infinite) set of mutually consistent statements. There can be contradictions between different parallel universes, for example in one the the car will be red and in another it will be blue. But a single parallel universe will always be self-consistent.

[@theM4R4T]

Sometimes, when thinking about multiverses, I wonder whether our universe actually exists. Maybe the whole universe is some sort generator that would "play" our universe if the right generation seed was supplied, until then we just exist in some probability space outside of what the reality actually is. Like with the Library of Babel website where you can find any book you could possibly write. But are these books a thing until you open them and generate them? Or is that a part of the mathematical universe theory?

[@blackdragonxtra]

Well, that would answer the pesky question of whether Mathematics is invented or discovered...

[@Carmenifold]

but if it were true and we're just discovering mathematics because everything is mathematics, then all other inventions are mathematics, which is a discovery, so would that mean that nothing is invented, fundamentally?

[@Martial-Mat]

There's a fine line between genius and madness, and I have the feeling that some physicists have jumped right across that line.

[@wmarae]

This guy was high in cosmology class.

[@RFC3514]

A lot of these concepts (like hierarchical universes) can be explained much more clearly using analogies with computer simulations, virtualisation, emulation, etc., and even things like superscalar CPUs and speculative execution (modern CPUs can start executing code that depends on some test _before_ knowing the result of that test - they start executing the most likely outcome, or in some cases both possible outcomes, and then kill the branch that turned out to be unnecessary once the result of the test arrives). It's a problem (or a lost opportunity) that becomes more and more apparent as different fields become more specialised - the people in one area don't necessarily know much about other areas, and fail to notice important parallels (which might actually be connected in some cases, but, even if they're not, can be used to get some ideas across more clearly). For example, a lot of algorithms used to compress audio and video have strong parallels with the way the human brain processes vision and hearing, and while codec writers do take some psychovisual / psychoacoustic elements into consideration (especially for lossy codecs, that try to preserve _perceptible information_, rather than hard data), I have a feeling that very few neurologists have ever bothered to look at how JPEG or MPEG work. If they did, they'd probably find some clues that could guide their own research, and they'd definitely find some parallels that would make it easier for them to _explain_ their research to other people. Even purely "mathematical" algorithms like LZW / LZ77 have some interesting parallels with human memory.

[@iLLadelph267]

#4: everything exists. there's a real universe somewhere, right now, that looks like a cartoon. one where light is 10x as fast. one where every KZbinr is required by law to like this comment. mind blowing

[@rage7658]

What would happen if you bring an object from another universe into ours? or viceversa?

[@claritas6557]

The right honorable Dr. Tony Padilla around 1:09 implied that scientists generally agree that in the abscence of eternal inflation the space outside of our cosmological horizon is comparatively tiny; are there any physicists here who can help me understand what the reason for this is? Or just point me in the direction of some papers? thanks

[@DreckbobBratpfanne]

I really like Tegmarks Book about it. Highly recommend it. .

[@ToniT800]

I have a question: if the universe is expanding(or better to say the space itself is expanding) so the distance between electron/protons etc, is also getting bigger. Why are those constellation dont fall apart? Or does the nature constants, which describes the equilibrium of this state also change with the expansion of space?

[@alejandrinos]

The distance between electrons and protons isn't getting bigger. Space is expanding, but the forces that keep the atom together are stronger, so the particles keep the same distance. Imagine that you are standing on a street, tied to a giant rock with a rope. The street suddenly starts stretching in every direction, but you and the rock always keep the same distance, because the street isn't stretching with enough force to break the rope.

[@davewalker2397]

The other two replies are correct in that for now, the electromagnetic and strong force are strong enough to overcome the expansion of space on a local level. But at some point far into the future, the expansion will overcome those forces, and atoms as we know them will not be able to exist. Freaky.

[@E.lectricityNorth]

Dave Walker Yes. Freaky indeed.

[@WischenbartChristian]

Forces hold them together. Even the weak gravity holds galaxies together, but maybe someday the expansion will overcome those forces and rip everthing appart

[@ratansingh395]

I have a thought...acc to max tegmark, in other universes there are identical copies of every individual and thing. But acc to him, every individual behaves in a different manner. But I think that of course there are multiverses in which there are multiple copies of every individual and thing, but i differ in the thought that if the universe has identical copies then why the matter within it behaves in a different manner. So I think that beyond the horizon there is nothing but copies of universe in which there are identical copies of everything here and they behave in a identical manner as here. Can you give me an insight about this topic?

[@animowany111]

I like the idea of the type 3 universe. I've been wondering about this sort of stuff for years (and still do), and I believe that there are no splits, but all these universes already exist. They just share the beginning of their timeline. (And there's at least an uncountably infinite amount of them) I think this fits with the idea of backwards time travel nicely, universes in which a paradox would happen simply don't exist. If backwards time travel is possible, it won't actually happen if it would result in a paradox in that universe.

[@noahyudkin5458]

The splits are a misunderstanding, the universe doesn't split just continues in a superposition of possible states

[@bopiweirdo]

I have a question that has bugged me for awhile. If you can travel to another universe doesn't that violate the law of conservation of energy? The energy that is in you is part of the total energy of the universe. If you leave that universe then the total energy is lower which violates the law.

[@Tethloach1]

what would it be like to build a universe? is their any possible way to determine the universes trajectory or future? is it possible to add energy to our universe?

[@lukasmiller8531]

Hey Brady, thanks for the video! You should do a numberphile on different mathematical systems, that sounds really interessting!

[@RulerEntertainment]

Tony is my favorite physicist. Please more videos with him!

[@cbraham]

Brady, Why not a series on the Constants?

[@Fallkhar]

I found this a nice subject to think about,I also don't find any of them hard to imagine but these theories are what really get my mind to think and play many other thing are not as in the lack of the better expression as interesting

[@SheezyBites]

So in the level 4 multiverse would there be mathematics that exists but is not within our universe? ie. structures or even operations that are as alien to us as a fourth physical dimension?

[@GhostCalib3rX]

The gravity equation for our universe is: F = G(m1)(m2)/r^2, where F is the force between the masses, G is the gravitational constant (6.673×10−11 N·(m/kg)2), m1 is the first mass, m2 is the second mass, and r is the distance between the centers of the masses. In another universe, the equation of gravity may be F = 0. Therefore no force due to gravity exists, and there is no gravity. Everything is a quark, never joining to another quark to eventually make a proton, never making a nucleus, atoms, molecules, plants, solar systems, and galaxies. Just an equal distribution of quarks, throughout that universe bubble. This is just 1 scenario. There are an infinite amount of these.

[@SheezyBites]

GhostCalib3r That's just a level 1 multi verse isn't it? G is simply 0 in that case. A level 4 multiverse assumes that the maths can change, so the equation is different and there is a universe where say F=(G - m1 - m2)^(r^2)... What I'm asking is based on that level, not simply a changing constant. One of the examples given in the video was a universe where multiplication and division (entire mathematical functions) didn't exist, so if that's the case could there be mathematical functions that don't exist in our universe?

[@TheHarboe]

SheezyBites I think you’re indirectly asking whether something that we cannot comprehend, can exist in a different mathematical universe. I’m not denying that it could, but if it exists we cannot per definition comprehend it. I don’t think it makes sense to discuss the existence of incomprehensible entities outside of religion.

[@GhostCalib3rX]

SheezyBites It's not a level one multiversez a level one multiverse has the same constant s as our observable universe.

[@honkatatonka]

Hm, would the following make sense for the many-worlds-when-does-it-split: we can assume a plank-time, the shortest-possible duration between two events, or the time required for light to travel plank-length (is this even possible?). Or think it as the shortest possible time we can assume between two measurements. If we can assume a plank-time, we could say that a universe splits at each plank-tick, between two plank ticks there is only uncertainty. That might sound a bit esoteric but this is only because of my low layman level :) Thoughts?

[@northupguy]

Is it possible to interact with these bubbles? What happens when bubble with different laws merge?

[@markusjacobi-piepenbrink9795]

Well done! Love your video!

[@kaisersouzei]

If, when we look far out into the universe and see very distant galaxies expanding quickly away from each other, couldn't it just be that, since we are looking at light that took millions or billions of years to reach us, we are looking at a what was going on early in the universe? Do you think, if we were to observe the light being emitted at this very moment from those distant galaxies, that we would maybe notice a slower expansion or even a contraction of the universe? Or, have there been simulated models of the universe that suggest that the universe will keep expanding?

[@EGarrett01]

Could there be more than one of these operating together? Like for example a bunch of bubble universes that are each splitting infinite times via Many Worlds?

[@SeanMauer]

I think that the information content needed to present our universe displays the intentional work of an intellect. There are many things about our universe that defy undirected combinations. In other words the specialness of our universe has never been rigorously done away with, because there are no workable random-only models, only vast assumptions.

[@googelplussucksys5889]

Well, you're crazy...

[@SeanMauer]

***** Here's a challenge, come up with a model of a universe that has different constants than ours does, and show, rigorously what this universe would be like, what would it's periodic table look like? etc.

[@googelplussucksys5889]

SeanMauer Not interested. Maybe you should loan Flatland at your local library.

[@SeanMauer]

***** I've actually made a YT book review on Flat Land.

[@TheSLK66]

One question, it might be silly though, from the entropy point of view in our universe, dS/dt >=0 at all times. Increasing the number of states would thus increase entropy which matches our universe (this could very well only happen in our universe). However, if we assume this happens in the multiverse space, increasing the number of universes wouldn't also match the principle? (Many worlds interpretation).

[@tub3scr3am3r]

MIND BLOWN

[@mindstormmaster]

If black holes generate spacetime singularities, could they be the 'walls' between bubbles in the level 2 multiverse? Highly energetic, and tears anything that goes into it apart, but maybe doesn't let it 'through' the wall?

[@GhostCalib3rX]

The walls are most likely the brane edge where h (6.62606957 × 10-34 m2 kg / s) breaks down.

[@MrZerausogaitnas]

min 15:36, "gödel's incompleteness theorem", make a video about that already!

[@arunganesan1559]

What does he say @4:21? He says something "brains" arises from this idea, I can't hear him.

[@paultensen]

Like this view of the total universe, mathematics is everything! this actually just blew my mind,

[@StarSpawn06]

The version of the 4 levels I've read has the 4th level as a multiverse derived from the the Simulation Hypothesis: It's possible that this universe is a kind of simulation by beings outside of our universe. This implies that other universes can exist with very different physical laws "programmed" into them. (obviously, these laws need not be connected to those in our universe by, say, string theory) I think this a more useful category (and probably less controversial) than the Mathematical Multiverse category. Also, it's been said that the Many Worlds category is in effect no different from the level 1 multiverse when unlimited in size. i.e. within this multiverse, all the possible configurations that can exist do exist, but they all follow the same physical laws. Hence, imo, a more meaningful classification of multiverses is this:Level I: Different locations / realms/ "layers in the bulk". Same physical laws, just different configurations.Level II: Bubble universes. Physical laws vary due to different solutions being realised for grand unified theory / string theory.Level III: Different "simulations". Full range of physical laws

[@topguntk870]

level 4 is not simulation. please do research moron

[@johnfarris6152]

Does the wall look like a wall or is it just not there to see for some reason?

[@qingyangzhang887]

Does inflation also inflate time, (i.e. make the time pass slower than other regions) as it is part of the fabric of space-time?

[@Carmenifold]

Could you not go one step further and consider not just all mathematical structures, but just all structures? All things, even the impossible ones, or the ones that can't be formally defined? Of course this is pretty heavily out of "science" and much more into "metaphysics", but *could* it conceivably be an accurate description of existence? Maybe this idea ends up being an unfalsifiable one that's so ultimately abstract that it has absolutely no bearing on anything we can see or possibly could see, but it's a fun idea to me at least.

[@joaogoncalves1149]

The transition from one bubble universe to a nearby bubble may be progressive. IE, the change in the nearby geometry on those extra-dimensions in each "point" (bubble) may be monotonic in all their domain (Riemannian geometry). Thus, you could "travel" between the bubbles using your car, but you would see your reality changing progressively until you reach a point where your local system (the car) starts to behave in a different physical way (use your imagination here).

[@chrisrushtonltd]

could you have a sum over mathematical structures similar to a sum over histories? in which our universe is the most likely mathematical structure?

[@hackamranneh4042]

Physical constants are the same everywhere and -when in our universe, right?. However, for level two multiverse, somehow it really feels awkward, as you might have a new universe "contained" within ours but has different constants. Would you please give me some answer?

[@momerathe]

a video on the different interpretations of Quantum Mechanics would be good

[@IblameBlame]

"You can't interfere from one to the other." Isn't interference (like a particle interfering with itself in a double slit experiment with individual photons) exactly a phenomenon of interaction between universes according to many world theory?

[@lzy7071]

Tegmark's level 3 multiverse is not based on the assumption of solving the probablistic model. It was, rather similar to the string theory, based on something much simpler and later interpretted as a level 3 multiverse. The assumption was: what if wave function doesn't collapse (no decoherence).

[@googelplussucksys5889]

Good, I was hoping for a bit more extensive coverage on various multiverses.

[@WayneJohnsonZastil]

One thing for sure is never found the end to anything, never hit a wall or barrier. I don't think humans will ever find answers as our planet won't last the journey. After reading Brian Cox's Human Universe it really opened my eyes and made me feel how lucky we all are to be around!

[@GuyWithAnAmazingHat]

Which is why we humans must leave this planet, like pollen, we must continue to spread and seed the universe.

[@cortster12]

What about the barrier of light speed? Or the barrier of the observable universe because of the speed of light and the expanding of the universe.

[@JWQweqOPDH]

***** I think that education and technology will help us survive more than having more of the same thing. I'm not getting into a long argument, just quickly sharing my thought. If we learn to understand processes in nature and improve our efficiency as a species, improved societies will be able to accomplish exponentially more than current humans.