Это видео недоступно.
Сожалеем об этом.
Can a Multiverse ever be "real"? - Sixty Symbols
HTML-код
- Опубликовано: 13 янв 2015
- A short discussion with Professor Mike Merrifield about the "science" of Multiverses.
A longer discussion on Multiverses at: • Multiverses and Consta...
New Objectivity channel: bit.ly/Objectivity
Visit our website at www.sixtysymbol...
We're on Facebook at / sixtysymbols
And Twitter at #!/...
This project features scientists from The University of Nottingham
bit.ly/NottsPhy...
Sixty Symbols videos by Brady Haran
I think what the Professor is trying to say is that , there may be evidence which we have not yet found and that it may exist. But we must maintain the default position of 'not there until found'. Otherwise , you can say anything is true -magic dragons, leprechauns, the tooth fairy. The default position should always be of disbelief until a good reason is given for believing it.
Exactly, the burden of proof comes into play.
Ollie Burton Exactly.
you missed flying spaghetti monster
Poepkop exactly.
Poepkop What do you mean i missed the flying spaghetti monster. Do you deny the great noodly one's existence. Hmph...heretic.
I absolutely adore Brady's devil's advocacy.
It's got that nice high pitch shrilly almost cockney chirp.
In times like this I like to refer back to Russell's teapot. So Bertrand Russell was a philosopher and he proposed this idea that somewhere out in space, orbiting our sun is a teapot. Just a regular teapot, nothing special about it. The teapot's orbit exists somewhere in between our own orbital path and that of the orbital path of Mars' around the sun. Now we know that space is vast and even that ring of space between us and Mars is so large that even if all the astronomers of the world pointed all of their telescopes in an attempt to locate Russell's teapot and the searched for hundreds and thousands of years they would not be able to locate it. Therefore the existence of Russell's teapot can be neither proven nor dis-proven. Russell makes the point that the burden of proof lies upon the person making the claim, therefore because he cannot prove the existence of such a teapot we must assume that it does not exist, the same goes for multi-verses, gods and ghosts.
Be careful though, because science is inherently inductive and thus cannot *prove* any claim. Since no claim is provable, to assert that the claimant must prove it seems a inelegant.
I think it is better to say that the claimant must demonstrate that there are consequences to his claim. If we don't know whether the consequences pertain, then we must accept that we don't know the truth value of the claim. If the consequences don't exist, then we know the truth value of the claim is false.
When it comes to multi-verses, gods and ghosts, there are no possible consequences to their existence or their lack of existence. It quite literally doesn't matter.
This gets into where, I believe, the two people were speaking a bit cross purposes. Within the teapot example, one could place a teapot in orbit and it would be there, even though their claim could not be proven or disproven. The interviewer was asking in the context of the possibility of something existing, independent of our ability to confirm it, while the interviewee was answering in terms of what could be confirmed.
Put another way, when asking the question "Could X exist", the interviewer was working from the idea that you can not say "No" unless you can demonstrate why it is not possible, while the interviewee was working from the idea that you can not say "Yes" unless it is possible to validate the existence.
neeneko Well said, but it becomes a problem when "X could exist" is stated, in either context, 1) without any conceivable proof, and 2) merely as an attempt to not accept REAL OBSERVATIONS and to confirm ones unfounded biases. The correct answer to "Could X exist" is just what the professor answered: "Only if you have the evidence could X exist".
Be careful. Because the one saying that there is no teapot is making a claim, too. So, the burden of proof for this particular claim is on him in the same way as for the other one.
As long as we don't have any evidence for the teapot, we shouldn't assume it's there. But neither should we assume that it isn't there.
dLichti "As long as we don't have any evidence for the teapot, we shouldn't assume it's there." You contradicted yourself. If the person saying "there's no teapot" has an equal burden of proof, you can't just *not* assume it's there. You have to prove it.
Which suggests to me that you don't fully understand what "burden of proof" means.
I cannot express in mere comments how much I appreciate this channel's discussions and micro-lectures. Thank you for your time and efforts.
Videos like this one can really make me appreciate the professor's knowledge. Its just brilliant!
“...I could phone them up and have a chat” has to be the most concise shut down response I’ve ever heard. Duncelike behaviour to proceed with the same line of questioning after this point I think 🤷♂️
Its refreshing to hear an expert setting clearly the limits of his expertise, the Prof is being interviewed as an authority on Physics, and was cautious of voicing his own opinions about the philosophy of multi verses, god,etc. Something not all too common today
Newton's flaming laser sword: If something cannot be settled by experiment or observation then it is not worthy of debate.
So glad the Prof absolutely hit the nail on the head with this one - once again Brady gets a schooling. I HATE the popular science media acting like these crazy unfalsifiable ideas are anything other than pure speculation. You even hear it from scientists who should know better. It's a fun idea to think about though, despite being unprovable one way or the other,
I absolutely love Prof Merrifield's discussion here.
Before speculating about quantum physics everyone should say how he defines the term "real" and "reality" for himself, only THEN the discussion can be started, because i see that many people have their own opinion on what they think is real and its always something different.
Finally a scientist openly admitting multiverse is not science. It's annoying to talk to people who mingle science with the meta physical. As far as science is concerned, if you can't test it, it isn't scientific.
I just found this channel, lovely videos.
While I understand what Prof.Mike Merrifield is saying about whether it's testable or not, I think there is a place for philosophical ideas to start a scientific process. There may not be a way to test whether the Multiverse exists right now, it's up to us to find a way. Just dismissing it as metaphysics is just being closed-minded. The consensus at the time of Einstein's “On the Electrodynamics of Moving Bodies” - 1905 paper on the special theory of relativity, was thought to be absurd by all the leading scientists at the time is a perfect example of what can happen when you think 'outside the box'. There can be a 'Quantum Leap' in understanding, if you'll forgive the pun.
I always like the jelly beans in a jar analogy for discussions like this. Is there an even or an odd number of jelly beans in a jar? Well until we take them out of the jar and count them, the answer is "I don't know".
Very (very!) nice talk - I love when the Prof. gets into these "abstract" discussions...
3:10 "For something to be real, I think it has to interact with other things and there has to be some observable consequence of their interaction."
I agree with the professors point on drawing the distinction on what is and is not physics. However I think one must be very cautious as to the implication of it. Einstein didn't came up with his relativity primarily because it was testable but because of the fact that it was logically/mathematically plausible and the fact that it can answer difficult question. Experiments always lag behind theories, and it should not limit us to think outside the box.
As others have said, Russel's Teapot comes to mind. But just about anything imaginable can be used, and that is the problem. "Unicorns might exist, we just haven't actually seen one yet," or "bigfoot", or any other thing that is imaginable but not yet proven by interaction. Prof. Merrifield's point is that, until an observation or measurement can be made, "multiverse" may as well be in that list.
Yep. It's the reason the null hypothesis exists and is fundamental to all of science.
stellarfirefly "Unicorns might exist, we just haven't actually seen one yet..."
I just considered the multiverse an interesting thought exercise before I read about the inflationary model. The more evidence there is for inflation, the more evidence there is for the multiverse. If the inflationary model is true, and we have empirical evidence to suggest it is, then the predictions of the model follow from the mathematics. Same as relativity and black holes. That doesn't make black holes absolutely real, nor the multiverse either. But it does point out that science is more than a bunch of factoids.
Mark Hornberger
...you do realize that relativity and black holes both have direct observations, right?
I love how this professor explains things. So simple yet deep!
The series Fringe is a great example! If like in that great series the multi verse did interact with ours then we would be able to detect and measure it and make experiments, but if those parallel universe had no way of interacting with ours then we would be forever ignorant of the physics and science
It's not physics right now, but maybe it will be some day, if it exists. It's still fun to imagine.
The problem is that we are trying to discover a Universe using our laws of physics which would not apply in the other Universe. This would mean that we would never be able to measure the other Universe as our laws of physics are completely different. I doubt it will ever happen.
Mulreay
You make an assumption that the laws of physical should be different but they may just the same in all universes. If universes has been expanding for an eternity in the multiverse then surely there might be echos of these in our own.
Stig Helmer Owen Prescott That is true but as the 'multiverse' is an idea due to infinity there are an infinite differences in how are universes work. So there are an infinite chances that the physics won't work and that they will. Hence a paradox that prevents us from measuring any other universe. Sorry I know I went off on a trail there but hard to explain my head.
+Stig Helmer If there are 'echos' of it, measurable echos, then by definition it is part of our universe
Unicorns aren't physics right now, but maybe they will be some day, if they exist. They're still fun to imagine.
Thank you Prof. Merrifield for existing
The question should be whether there are mathematical models of multiverse as such, not "do you believe in infinite number of universes". These kind of questions should be on Philosophyphile channel or something.
Brady and Merrifield are talking about the multiverse in slightly different ways. Brady is saying that the possibility of a multiverse exists, except you wouldn't know it if it did. Merrifield is simply saying that although the possibility might exist, there isn't any way to confirm it, and we must maintain that it doesn't exist until evidence for it arises.
This touches on what actual reality is. Is reality what you perceive and experience through your senses, or is there an absolute reality outside of the human mind? I could propose that the entire universe is filled with invisible, non-interacting unicorns. If they exist or not doesn't matter, as long as they don't interact with us in any way. You could go deeper and say that the entire universe is an experience created by the mind. Everything you see, interact with and experience could just be a simulation being made by the mind, but as far as physics goes, it is meaningless to discuss whether or not this is true. We have to rely on what we can test and verify, anything else is just philosophy.
In my opinion, and seemingly the professors opinion, reality is what we experience and can interact with, which in this case other multiverses aren't a part of.
Hahalol663 The discussion in the video assumes that there is "an absolute reality outside of the human mind" in that observable consequences are the same for all minds interpreting such data.
Same with the "are we living in a perfect simulation?" hypothesis. Virtually untestable. Though, there are some clever mathematics and strange empirical observations we've made in the universe to potentially suggest there may eventually be discovered ways to subtly probe beyond what we think possible, even though we have nothing resembling "proof" currently... I like to remain slightly optimistic, at least ;)
Merrifield covers the topic beautifully. 1. The universe is by definition everything that can possibly be observed, and another universe is by definition unobservable. 2. If it has no interaction with anything in our physical world, it's not physically real. And 3. if it cannot even in principle be proved or disproved, it's not science; it's science-flavored philosophy.
I have to assume this interviewer is trying to play devil's advocate, because it's hard to imagine someone being involved in these videos who has such a narrow and frankly ignorant picture of modern science. I don't say this to be mean, but the whole "I'm going to take it on faith that the multiverse is real and then require someone to disprove it" angle really makes me wonder how you can have this many conversations with scientists and still think that way.
I enjoy the parallels drawn between physics, philosophy and theology here.. Maybe, if you look closer, these separate subjects are more linked than we allow?
If there is even a way to test this. I have a feeling you would need very detailed samples collected at the scale of a galaxy or super cluster to actually map out the subtle interactions
I think there should be a distinction between interactions and observing the interactions. Interactions could happen even if they're unobservable to humans for the foreseeable future.
I must say, kudos to the comment section for not getting into a religious war and sticking to the topic at hand. Round of applause.
I agree, and have used this sort of reasoning in other areas. Basically, unless you have a precise definition of "exist" that I haven't heard of, a thing cannot exist unless it affects the universe somehow. And if there's no possible method of testing an idea--even hypothetically--then it can't affect the universe (because looking for that effect would be the test!). So again, unless someone can supply a more precise definition of existence besides "affects the universe in some way", then deductively speaking, anything untestable does not exist. AND, one level further, anything that is hypothetically unfalsifiable also does not exist--because anything that can be tested can hypothetically be falsified (by a negative test result).
Argument from Ignorance Fallacy, Brady.
I feel so sorry for the physicist in this. He very clearlly explains himself, and makes perfect sense, and yet the guy keeps making the same point and asking the same question over and over, and the physicist has to keep answering it again and again in slightly different ways. I have to do this a lot with people. In the end I just give up usually and leave them thinking they outsmarted me lol
Merrifield is brilliant. I too have never had faith in the multiverse hypothesis.
I know this is incredibly unlikely, but if we come up with a theory which predicts many things we can observe (and turn out to be accurate) *and* a multiverse, I'd say it's reasonable to assume there is one. Won't change anything other than the way people think about existence of course as it's (probably) not directly relevant to testable physics, but still. After all, appreciating the existence of everything is at the heart of all sciences, physics especially
The thing I don't understand with multiverse theory is how do we even know those constants are free to vary? If the dice only has one number or if it's weighted by something we haven't discovered yet then you don't need several tosses to get the number we got. If you can only see the result of one toss then how can you possibly know if it's weighted or if there are other numbers?
Brady, I like how you ask questions :) I think you learned quite a lot since you started making these videos, i remember you used to be less an "interviewer"/interactor and more just a camera man, now you've become an integral and relevant part of the videos, with your lines of questioning, etc :)
(Maybe i'm just imagining it and you were always like this, not sure :-D)
I for one completely agree with Professor Merrifield. The idea of a Multiverse is that of faith. Until you can scientifically test something's existence, belief that said thing exists is based merely on faith. To be perfectly honest, I find God to be more scientifically acceptable than a Multiverse simply because of the fact that God is, in a sense, testable. Testable, that is, in the form of prayer. (This is NOT meant to start a religious debate! I am not saying God exists, I'm not saying he doesn't. I'm simply proposing the thought that the idea of God is more scientific than the idea of a Multiverse at this particular point in time.)
There is a difference in having faith and having an open mind. I am open to the idea of a multiverse but I'm not going to believe it until someone manages to produce some solid evidence.
***** I have two problems with your comment.
1. "We know that at least one universe exists."
Obviously, I agree that we know that one universe exists. However, I don't believe that the fact one universe exists automatically implies that multiples exist. Although, I agree that from a naturalistic perspective and from our limited point of view, a Multiverse, on the surface, sounds more reasonable than a God.
2. "The Multiverse theory is preferable to any 'God theory' because it doesn't posit the existence of supernatural phenomena."
Your argument here is actually totally false. You imply that the Multiverse theory is not supernatural. However, supernatural means, "attributed to some force beyond scientific understanding or the laws of nature." As it stands at the time of writing this comment, the Multiverse is no less supernatural than a deity.
Perhaps that's my opinion, but there is just as much accepted scientific evidence to support a Multiverse theory as there is to support a "God theory."
Stuart Hull Re: double blind prayer fro healing showing no effect. Citation please?
I don't disagree, I just want to add that I find there is also levels of plausibility here. I know this is totally non-scientific but I find the multiverse ideas to be more plausible because of mathematics.
I mean...if your test of God's existence is the effectiveness of prayer, then I have bad news for you: that study has been done several times, and each time has shown no causal link between prayer and medical recovery. So the test must revert to the null hypothesis, meaning if that's your only test...sorry, your hypothesis was wrong.
Merrifield has always been one of my favourites in your videos, Brady.
More from him is always *greatly* appreciated.
Also Phil Moriarty and Meghan Grey.
Also mathcomputers aren't really my thing, but Tom Scott, James Grime, and Matt Parker are especially beloved by me as well.
I almost forgot Ed Copeland, I'd love to see more from him as well.
And I'm still forgetting some.
These are just some of my favourite Haranprofs.
It is a compelling argument. Much like proving or disproving the existence of radio waves to a pre-metal culture.
Eloquently put Professor. You fielded some 'awkward' questions by keeping the discussion on topic (physics). Anything untestable either isn't real or doesn't matter. If it's untestable, it's conjecture.
I think he meant to say that if something is in another universe, it by definition can never interact with our own universe, so in that sense it can never be validated by definition.
If we could observe, interact, measure another universe then surely by definition it is part of the familiar universe.
Something that is real does not require us to be able to test or observe it, but in in order to know whether or not it exists does! I do not know why the interviewee did not make that distinction.
It's ironic though because the thing that is most real to us, our consciousness, falls into the same category of not being able to be quantified by science.
As Max Tegmark said, you only need one testable hypothesis in a theory to see if it is correct. But, of course, that one hypothesis has to lead to the conclusion of your untestable point.
By "one testable hypothesis", I mean at the bare minimum. You need a theory that concludes a hypothesis must be correct.
This Brady guy is a GREAt journalist.. great witty questions .. also prof Mike killin it
I think the word "multiverse" is silly because universe to me is a concept like infinity to mean the known dimensions. A multiverse always sounds like my concept of a universe but having different shapes and nodes. I would prefer to add a new dimension or vector to define the 'direction' of spacetime then I can say different vectors of spacetime exist - not universes.
If you think that you think you only think that you think. In other words: it is not philosophy if your hypothesis can not be falsified. Philosophy is the mother of all science. And it follows scientific principles. And therefore not every ontological discussion is a philosophical one.
I think you need to create yet another channel to talk about philosofical topics like ontology, epistemology etc. since you seen very interested in that sort of thing
Oh Brady you almost did it! It was a close one to beat professor but not today! I believe in you you can do it!
By the fourth minute, we felt into a fallacy issue. It one makes a statement, it is that one's duty to back it up logically or factually. When one says something exists just because it cannot be proven that it is nonexistent, that one is pushing the responsibility of proof to the counter-arguer. This is an example of the classic fallacy of the Reverse Onus Clause. If a reserve onus clause was logically correct, one could make up anything and call it truth. For example, I could make up a all-might being called Flying Spaghetti Monster that has the distinguished power of disguising itself from all experiments and observations. If the reserve onus clause was correct, that being would have to exist simply because it cannot be proven to be nonexistent. However, in contrary, the opposite applies. The one that makes the claim must proof it.
the professor makes a really good case but i agree with brady. even if there is seemingly no way to prove something there's still a chance that it may exist
The professor agrees with him too. It may or may not exist, but the question doesn't concern science anymore. It falls on the realm of philosophy.
True that there is still a chance, but it is not logical nor reasonable to discount the "real" for the "could be" until the "could be" is proven.
Brand Lift "Sigh"... :-(
The chance of something existing is useless to prove anything. Give me 1000€ now and I'll give you back a million tomorrow! Would you do it? The chance you get a million is there!
Define "exist".
I would like to hear the professors' thoughts about three different types of "multiverse" hypotheses, and how they compare with each other.
First, the traditional multiverse idea described in this video, where the individual universes differ by their basic conditions - like comparative strengths of different constants, and which is most relevant to things like the anthropic principle.
Secondly, the many-worlds interpretation of the quantum physics, where each universe is further divided into an infinitely branching tree of different possibilities, or world-lines, each split triggered by quantum level events that could go this way or that, and thus causing eventually large differences as these minute changes accumulate into something larger. Or perhaps there are likewise an infinite amount of different pasts converging into an observable present, as per CPT-symmetry?
And finally, perhaps the most intriguing possibility that doesn't really even include any quantum head-aches or different natural constants. As the most recent experiments seem to suggest that our very own, observable universe is in fact spatially infinite (flat) and expanding, it would be a logical extrapolation to say that even within this one universe, there are infinite Hubble volumes, each behaving as though they were an unique, self-contained observable universe because you simply can't make any observations beyond your own Hubble space, and you're always in the center of one of those "bubbles".
The implications of this variant of "multiverse" are, in my opinion, the most shocking. Technically, if there's an infinite amount of these individual "bubbles", then some of them will be quite close to each other in almost every minute detail. There may be duplicates of structures that would seem familiar - such as perhaps our entire planet Earth, or even the entire Solar system or Milky Way Galaxy, or Local Group, etc. There may be variations or differences in large or small scale, but in this case, the laws of nature would still be the same in all these individual observable universes, or Hubble volumes. Simply from mathematical standpoint, it would basically be a certainty that within these infinitely different universes, an infinite subset would be almost exact duplicates of our observable Hubble space. In these near-identical worlds, there would be duplicates of me living out similar or different lives, perhaps even writing some version of these exact words about... me.
You should talk to Quinn Mallory.....I hear him and Professor Maximilian Arturo have created a way of doing more than just simple observations of other universes.
Brady is unusually inquisitive; and the professor is plainspoken, and handsomely modest with regards to ultimate philosophic questions. Well done!
I wonder how professor Merrifield would feel about equally philosophic concepts that are more useful to physics like the idea of a 'random' occurrence, which is so necessary for probability. I wonder if he would say that "all we can say of random events is that upon repeated experiment they tend towards randomness," rather than saying there outcomes are uncaused. Seeming a philosophically modest man, I think he would...
If you think we're just going to forget the whole 'wind turbine' incident, well then Brady, you have another thing coming.
I'm not sure if this would work as a test, but it seems like a hypothesis based on the multiverse idea could suggest that when we find a Theory of Everything, it will be able to explain all observed phenomena, but will not be able to definitively explain why certain physical constants have their known values, as these would be literally random, or at least semi-random. If the probability of the particular values inherent in our universe was small enough, then it would seem more likely that there was a multiverse with many different values, and that our observations were the result of the Anthropic Principle rather than incredible luck.
In contrast, if the ToE was unworkable with anything different from the observable universe, then it would suggest that a multiverse was unnecessary.
Neither answer would be definite, but it seems like there would need to be a discovery of additional unobserved physics in either case to make a strong counter argument.
I don't know enough about physics to Guage if this is workable, but it seems like a way to gather more evidence that wouldn't require any unlikely development like FTL to collect.
Please correct any misunderstandings I have.
The guy is asking perfect questions
Another great video but for the sake of us mobile users can your links in the description please be RUclips links as the ones currently use open a browser window (which makes pants viewing on an iPhone)
I think the professor is right. Using the man in China analogy:
If we make up a fictitious Chinese man choosing a random Chinese name, an age, a height and a description, that person *might* be REAL if we happened to describe a person that actually exist in China or somewhere else on Earth, but we have no way to know unless we can somehow check if there is someone by that name and age and height and so on.
In the same way the Multiverse *might* be a REAL thing or it might be just a theory, but without some way to test anything about the theory, the question if it is REAL does not make sense.
The multiverse isn't normally a standalone hypothesis, however. If the eternal/chaotic inflation model is accurate (and it does have empirical evidence going for it) then the multiverse is one of the predictions of that model. Many theories have predictions that we haven't observed yet. Einstein's Relativity and black holes, for example. That doesn't mean relativity isn't science. The multiverse is a prediction of a theory, not a theory itself.
"To be physics you have to be able to test a hypothesis." Yeah, STRING THEORY.
To be fair, it's not an officially accepted theory, it's a hypothetical model. The naming conventions, as in this case, aren't always consistent.
Somebody doesn't like String Theory
Give a list of possible experiments to show string theory is an accepted theory.
Having Fun Not at the possible moment . But in future we may ...but for now Math is your biggest proof .
String theorists have proposed experiments that could test it. It's just that those experiments aren't feasible, at the moment.
That's a far cry from the multiverse hypothesis, which was actually explained quite poorly (different universes do NOT compete with each other), which has no testable predictions. Yet.
I stood up and applauded.
I am sick of these "science" shows for the masses always sticking in the "multiverse" idea. It would be fine if they explained how it isn't scientific but they don't, they just throw it out there to impress people.
Brady's questions are up in the realm of philosophy. You can't bring them down to physics
IF there is a very subtle influencing of universes between each other, what about hyperdimensional planes? Are those considered part of our own Universe or could there be a conceivable interaction between these proposed hyperinflating bubbles, who may even lay on top of each other, within the different dimensions? Fascinating to think about it really.
I've always wondered if other universes existed where conservation laws didn't exist, such as conservation of momentum or mass.
Multiverses are logically deducible from inflation theory which is to a small degree, testable. So even though the concept of a multiverse is currently untestable. it is logical to postulate their existence as an extension of inflation theory. Likewise with string theory. The fact that so many constants are derived from string theory strongly suggests it's existence regardless of its' "testability."
He does have a point there. With multiverse interpretation or theory, we exit the realm of physics and enter the realm of philosophy. Is it then real or not goes into semantics, sure, but I think the problematization of the concept of "real" is necessary and meaningful. And again, such analysis exits the realm of physics and enters the realm of philosophy.
I think the confusion here stems from a so called use-mention-error (cf Dan Dennett): For all intents and purposes, other universes do not exist because they do not interact with our universe and cannot in any way be observed or inferred (that is what Prof. Merrifield is talking about), but you can still discuss the idea of other universes existing, and this idea is certainly real (this is what Brady is talking about).
Sir Mike Merrifield Newton!
It's conceivable that one day in a lab, an experiment could expand a bit of quantum stuff into a mini universe. Assuming its spatial and temporal dimensions were orthogonal to ours, I wonder how we'd pierce through them to make observations.
I love the etymology of the Danish word for reality, "virkelighed". It is very closely related to the word "virke" meaning work or function. In Danish, for something to be real (virkeligt) it has to work (virke). It has to do something. If something can not be interacted with, then it is not really... real.
I totally agree with Professor Mike Merrifield here. The only way the concept of a mulitiverse becomes interesting is if we some how can test if they exist (And then well what we call the universe today is just shown to be a small part of a great whole. A bit like how once people believed the galaxy was the whole universe.)
Brady you asked "Does a person you've never met actually exist in China?". The professor got confused or distracted, but I'll show you the flaw in this analogy. So if you describe some person to me and tell me he lives in China, how can I be sure that you are not lying to me? I have to have faith in your words and believe he actually exists. And that leap of faith is what's NOT scientific. The scientific way would be to doubt your theory of that person's existence and try to confirm it in any way. Then publish the finding so anyone else who doubts your finding, could recreate the experiment and confirm it for themselves.
Which is exactly what he said.
Great channel, I watch it regulary. Thank you for your effort! :-)
BTW, why is it called Sixty Symbols?
To support the professors point, one could simply state that, "If you can't tell the difference between demonstrably reality and fiction, then (frankly) you can't tell the difference between reality and fiction." Evidence and demonstrability are the best litmuses we have. Sure, there might actually be other universes out there, but you can't be any more certain about them than can about Polka-dotted flying unicorns. Without a litmus, reality has no real meaning.
Back to the example about a person living in China, you're right, we can just call them up and have a chat, but what a bout back before instant communication existed? I'm sure we still knew people lived in China but just had no way to prove it, other than traveling of course, so maybe one day far, far away we may actually have the ability and intelligence to test this theory
If you can't interact with something at all, ever, the question of whether it is real or not is irrelevant. It is impossible to answer and it has absolutely no consequence.
It's philosophy, they'll do anything they can to explain away fine-tuning. My undergrad professor used to get pissed when I brought up the multiverse.
If you can observe it and test it, it is physics. If you cannot observe it or test it it is philosophy.
So what you're saying is that String Theory is...
Philosophy. Until they can make a prediction and test it.
I don't understand why it is said that you "need" to have had multiple universes in order to arrive at this one. Imagine a die with 1 million faces, you roll it once, and it lands on 571,293. What are the chances of that? 1 in 1 million, it's an incredibly small chance, but it had to land on SOMETHING. There's no point in trying to think about the chances retrospectively because you only have a sample of 1, and it's already happened.
i liked the interviewers questions, he was aksing pretty much the exact same things I was going to comment about.
He purposefully asks stupid questions for this very reason.
oBLACKIECHANoo Well you're a lovely person ;)
Dodgy Smalls What's the matter? did da wittle baby have to ask those questions too?
Agreed! Brady does this all the time. It's remarkable.
MrScotty, we didn't get some magical information from the universe telling us there is a multiverse, we created this own idea in our head because our universe existing in this state is a damn mathematical near impossibility.
So does this mean it DOES exist because we think it does? No. The professor is right, we need to test to see if it does and thats that. As of right now there is -0- evidence of a multiverse.
"Just because we can't test it doesn't mean it doesn't exist" Again, we invented this idea, just because we think it may be a possibly DOES mean it exists.
Lawrence Krauss makes the argument that _if_ we had an accurate theory that explained why there are three families of particles, why the mass of the various particles take the values that they do, _and_ a consequence of that theory is the existence of a multiverse, then it would be a reasonable to take the multiverse seriously, even if we didn't have direct observations of it.
All of the comparisons to Russell's teapot argument are off the mark. There are no theories where a teapot is one of the consequences that happen to fall out of the theory, but there are multiple theories that have a multiverse as one of their consequences.
Russell's teapot begins with "Imagine a teapot..." while the multiverse starts with "Here are some theories of space-time that may be testable, and oh by the way one of the consequence of the theories is a multiverse.
Some consequences of quantum theory was the existence of the positron and particles traveling backwards in time. People took those consequences seriously even though they sounded completely impossible.
The universe has a certain progression as you observe the different layers. Some outcomes are more evident than others.
4:02. Agreed.
2:43 4:02
!!! was looking for this
What do you get if spell dog backwards?
Checkmate.
Ever heard the one about the dyslexic agnostic who lay awake in bed all night, wondering if there was a dog?
E. Lectricity LOL
That was the weakest thing ever XD
Damnit E, you beat me to it... Except I heard it where he was also insomniac and can't sleep because he stays up all bight wondering bla bla...
Gio Best Come to think of it, I think that's the original way I heard it as well. Not sure where I picked it up--I have a feeling it may be from some decades-old comic strip.
I can be a weak mortal not to design an experiment to render philosophy as physics, but then again it remains a probability: I may be a rather strong mortal, who can design any experiment, and yet, I can't confirm the multiverse.
So, what is a pragmatic thing for me to assume? In any case, it remains an assumption, and thus by definition, philosophy.
If one universe expands into another universe, would it then be detectable?
To put it another way that Mike:
To be acknowledged as real, it must be distinguishable from non-existence.
Correct me if I'm wrong but when the Prof talks about different laws of physics, doesn't he really just mean that the standard model has different constants and the emergent "laws" are different? ie generalised quantum theory is still at the heart of everything, or are we talking about a completely different set of rules?
It may well be both cases
I'm wondering how these arguments would look if the multiverse was a requirement of our best physical mode, an inevitable consequence of the maths behind it l (as far as I know, it isn't). This would make it similar to a very high-energy Higgs boson, for example; predicted and necessary to complete the model, but beyond our forseeable capability to detect... Would these circumstances make the multiverse more acceptable as a scientific idea rather than a purely philosophical one?
Believe me, multiverses are real. I have my own reality set up just how I like it but this universe keeps on butting in when it's least convenient.
a fish swims across the oceans but can never know there is land beyond.
a bird flyes around the globe but does not know about the space above.
a wolf howls at the moon but does not know about stars and galaxies.
a man looks everywhere from atom to the edge of universe but can not detect parallel universes.
all of them are content in a solid knowledge what they know is enough and probably all there is.
Karl Popper says in order for something to be a scientific hypothesis, it has to be capable of being falsified, capable of being proven wrong. That's what makes something science.
Brady Haran, thank you so much for doing all these amazing videos on your many channels, I'm a huge fan, but I wonder if you missed an opportunity for a question, specifically in the longer video with Professor Laurence Eaves.
Question being: If 500 years ago we didn't even have a simple telescope, with which to test the proto-heliocentric theories of astronomers ranging from ancient Greece to 5th century Rome and India, what is there to stop us from inventing new tools with which to explore in 500 years time what we cannot even realistically comprehend today?
On a side-note, I agree with Professor Eaves that meta-physics or god(s) are not interesting.
If the multiverse is the reason why gravity is so weak then we do have a testable interaction.