Tony makes the case for string theory in an earlier video: th-cam.com/video/Q8ccXzM3x8A/w-d-xo.html Ed discusses Cosmic Superstrings: th-cam.com/video/03vIkZR2hNY/w-d-xo.html
i think we should (for any normal people, like me, an average joe viewer) clarify that string "theory" is a mathematical theory, not a scientific theory.. there is no scientific evidence for it.. im guessing it is testable, but in our timeline, extremely difficult to test? could you elaborate? thanks a lot
@@culwin Reminds me of a certain "documentary" series with Kirk Cameron... "we asked random people on the street leading questions that mix up multiple scientific frameworks if they think a different scientific theory is correct, and they didn't understand, so the science is wrong!"
@@culwin assuming you're being satirical, it does actually make sense to ask non-string-theorists. it's not like physics is just string theory; other physicists have opinions on string theory that may also be valuable
That's the media for you. Science would respond: "with a probability of xyz and an error margin of abc if conditions 1-73 are met we can assume that ..."
No extra dimensions and no super symmetric particles found yet... But all our experimentation so far has given us vital insight on which direction to move the goalposts in!
“Moving the goalpost” is something from politics. That is not how science works. There are no “goalposts” to move. Every single model of new physics has a set of free parameters which form an (often) continuous space. Physicists don’t go out and tell you “my theory has these exact parameters.” That is not how this works. Theorists describe the space of free parameters allowed by their model that is consistent with all our observations. The experimentalists take measurements to search new regions of unexplored parameter space. Your reference to “goalposts” belies a superficial understanding of the scientific method. If you try to think about actual physics research like you think about politics, you will be wrong every time. It’s much more complicated.
@@heywayhighway Mwah, I think that is yet to be determined. For example, recently some evidence for cosmic strings was claimed. Not confirmed, but it would go a bit to far to say it **cannot** be tested. If you say that we are not sure yet how to test it, I would be inclined to agree though.
@@heywayhighway Yeah, but that is not enough to justify a "can't be falsified", imho. The stronger the claim, the stronger the evidence required. Plus, 40 years is a mere drop in the ocean. How long did the atomic theory take to be confirmed, for instance? Over two millennia. Was it unscientific in the times of the ancient greeks because they did not have any means of confirming it in sight? I wouldn't call it that.
Unfortunately it looked liked that for some time now, and all the new experiments and observations are only making it worse for The String Theory. I believe that the only thing that is holding it is how beautiful and nice the math looks, and it would be so damn fine for it to work. (Controversial statement ahead: just as the case for Planet 9)
Iirc he also says that the final theory of QG will most likely contain ideas inspired by string theory, such as holography, even if ST itself doesn't pan out.
I prefer Schwing theory, developed & popularized by professors Wayne Campbell & Garth Algar. Since it's inception (circa 1990 in Aurora Illinois), no aspect of Schwing theory has been seriously challenged or proven wrong. Many expect Campbell & Algar will win a Nobel prize for their towering work any day now.
🎵🎵 Is this the real life? Is this just fantasy? Caught in a paradigm, with no escape from reality Open your eyes, look up to the skies and see... I'm just a poor boy, working on Schwing string theory In quantum foam where strings may glow, they vibrate fast, then softly flow. Any way the wind blows doesn't really matter to me... 🎵🎵
Two things I've been hearing from people working on string theory are: (1) Forget about a theory of everything. Strings are playing the role that harmonic oscillators are playing in vanilla QM and QFT, and nobody is asking if harmonic oscillators are "proven". They work for the theory and let you solve problems in quantum gravity, which is the main thing they want to do. Nobody should throw out the whole of string theory for the same reason nobody has ever proposed throwing out harmonic oscillators and raising/lowering operators. (2) Stop thinking of them as "extra dimensions of literal space". The better term to use is "junk" degrees of freedom. Behind that is the proposition that it's better to recognize that what we call the 3D of literal space emerges from entanglement states than to think of the extra degrees of freedom in quantum states as literal curled up space. A related point they'll sometimes make is that if you want a vacuum background of a certain large-scale dimensionality, one way or another you'll need more degrees of freedom constructing the vacuum background. If there were only 3 degrees of freedom for constructor states (whether or not its strings), then the vast space of possible vacua states would be less than 3 macro-dimensions and the 3D ones would be abnormal, which is not the universe we live in. The fact we live in a 3D macro-dimension space if anything argues in favor of more degrees of freedom. That's before you even get to the points that string theory isn't even about strings, we don't have the full theory set yet, but we have a program that is at least pointing us in the right direction, and the math you need to make progress in string theory is they math you're going to need for whatever shape the next gen theory will look like in any event. Things like that.
Except harmonic oscillators were born out of abstracting physical observations, while strings are essentially math exercises. I have nothing against doing math, but don't call it physics.
Number 2 here seems to be relying on some flawed logic. How many universes have been observed for us to know, or even suspect, that a 3D one is unlikely with only 3 degrees of freedom? And even if it would have been unlikely, that clearly does not preclude its existence.
Ed Witten once said (paraphrasing): “the important thing a scientist must do is to pick a topic to work on that is neither too easy and trivial to be fruitless nor too complex as to be a dead-end with no actual chance of success.” Maybe Unifying the Forces of Nature is too ambitious a goal when we don’t quite understand many aspects of the fairly established theories like General Relativity, Quantum Field Theory, The Standard Model, The Lambda-CDM, Chaos Theory, various interpretations of QM, etc…
With the limitless number of graduate students slaving away at one idea or other, there should be fair allocation to those working on an idea that may be useful.
There's been some, and the results were all negative. Which only made some of the solutions for string theory go away since String Theory is know of the co-called "landscape problem" - having enormous number of possible solutions. The biggest that comes to my mind is Supersymmetry and trying to find a partner particle for any known particle with LHC. There could be some gravitational effect of comic strings in cosmic microwave background - nothing has been found. They should allow for unusual particles or interactions that could manifest in high-energy cosmic rays. No anomalies were found. They could influence the spectrum of characteristics of primordial gravity waves. Nothing's been found although this one is fresh I think.
*Pre*dictions, no, but from what I hear it *has* been used to successfully make some accurate but not very impressive *post*dictions. Something like, they can do some calculation to say something like “according to string theory, the ratio between the masses of these two particles should be in [some finite but kinda big interval]”, and it is indeed in that interval. Which, like, is a lot better than the theories that cranks on youtube post in the comment sections. That’s not a high bar to clear though.
There are too many things we don't know yet. If we had better understanding of the early universe, they could make a more precise prediction about cosmic strings, but we're not there yet.
@ You are talking about calculating the ratio of particles masses - the intervals can be so wide, that they encompass almost any possible experimental outcome. That is really not meaningul in a any way.
"If i can define the parameters of my search space, and I use arguments of beauty to define why these parameters make sense, and I add these VERY specific assumptions in the mix, THEN String theory is the only one that fits!" .... Yeah.... very convincing ;)
That's exactly why I don't think string theory, dark matter and dark energy are real. They're all bandaid solutions to 'fix' the problems with the Standard Model. They tried to do it with classical mechanics, then quantum came along and proved it all wrong. I think it'll be like that again, the problems are too fundamental, we need a new way of thinking.
I don't even understand string theory well enough to have an opinion on if it's true, but I'm tired of hearing about it. If it's right around the corner, great. If not, fine. Update me when there's a result. I don't mind if it gets funding, because there should be more funding for study of a wide range of theories and models. But could we just tell the string theorists "Come back with a result or stop clogging the airwaves" , please? Its the most over-publicized thing in science.
I _think_ you're allowed to not watch/read about it ? Not totally sure, maybe the rules are different where you are but that's been my experience at least :). (less facetiously, that's not how science works. Scientists don't just "go away" then come back when they're done - discussing it and releasing new papers related to string theory IS science in action and what, for now anyway, makes it an active field of study. Also, _surely_ AI is _actually_ "the most over-publicised thing in science" right now ??)
Fair point about AI but it's only been wildly over-publicized for about 6 years now. String Theory has been overblown for ten times as long. And notice I said "over-publicized", not "over-studied", because my gripe isn't with scientists publishing research. It's with science communicators and science media (which I consume plenty of since I'm a fan, and will continue to do so) and that they won't stop talking about string theory *even in situations where it isn't relevant*. People who don't work on care about Strings get asked by interviewers about String Theory. It's kind of ridiculous.
@anonymes2884 _Assuming_ it's an over-publicised topic, then one's ability to "not watch / read about it" does *_not_* alter the fact that it is over-publicised. Moreover, one's ability to "not watch / read about it" does *_not_* imply that one shouldn't complain about it being over-publicised.
Not really sure what Tony means when he says that you can test things mathematically. Sure, you can test that the mathematics doesn't imply something unphysical but, ultimately, the question of whether string theory is a model of the universe can only be a question of physics. It's not enough to show that the mathematics is internally consistent: to be a theory of how the universe works, it needs to be consistent with the universe.
On one hand, you're not wrong. But for mathematical concepts like string theory, they can be so complex that it's not intuitive what exactly they entail. So you can investigate if the math is consistent with other theories and with known physical phenomena. As a loose analogy, perhaps you come up with a model that will predict your income in 20 years. You might test your model by considering bizarre circumstances, like if you get divorced 4 times and have 15 children. If your model still gives reasonable estimates, you can have more confidence in it, while if the model says you'll be a trillionaire it's probably wrong.
It’s not just a matter of internal consistency, but consistency with the low-order predictions of, say, general relativity. If it was not consistent with GR, that would be a big red flag.
@@SpaveFrostKing Right, but the only conclusions you can draw purely from mathematics are either that it's wrong or that you don't know of a reason that it's wrong. You can't conclude that it has anything to do with the universe without looking at the universe.
@beeble2003 Testing string theory purely with physical experiments is extremely, ridiculously expensive. If we can rule out string theory by first seeing if it's consistent with everything we know, we can save a lot of money.
Maybe if you could somehow mathematically prove that there can only be one physically consistent universe that agrees with the evidence we already have... But I would not get my hopes up for that.
@ralffig3297 they might be wrong, they might be right. either way, this is science. I don't get why you care so much. they seem to be very satisfied and accomplished professionals
To be blunt, unless you are a mathematician, you should not be spending your time on string theory. What we need are new ideas and evidence-driven research, not physicists getting lost in the weeds of mathematical technicalities. It’s time to focus on approaches that can lead to tangible progress in understanding the universe.
@@keffbarn There are plenty of new ideas but nothing comes close to string theory. They all run into problems on a much more fundamental level than string theory does.
As others have said, it would have been nice to hear a little more variety of opinion. Asking some people that are not string theorists would have made for a better video.
That's a fair point and I think any video like this should be looked at within the suite of other content on the topic - just to put this video in some context, it is part of a quickfire series of videos where viewers are asking questions of Tony and Ed on all manner of topics... Here is the list which I am expanding on as more videos are added... th-cam.com/play/PLcUY9vudNKBNLpmQg4SSZ6tMsyDldilnA.html
The problem is that you need to ask people who are well-enough informed about string theory to have something worthwhile to say about it. But mostly, those people are string theorists. The honest answer from the overwhelming majority of non-string-theorists, even within physics, is "I don't know enough about it to comment, really."
As a programmer of a lot of complex algorithmic structures and data, string theory reminds me of systems I've built where I've started with a fundamentally sound and solid idea, but as I begin to find the flaws, I keep having to patch them in ways that become more and more untenable, eventually resulting in a system that's on the verge of collapse. And when I step back and look at my solution, I realize that I've been digging *way* too deep into algorithm that's clearly not working and I need to switch to a new solution. Now, I don't know a lick of physics outside of high school and youtube, but String Theory feels like it's in that place. They've been working it and massaging it and desperately searching for new particles and new explanations to fill in those holes for decades now, and it's just not working out. I wager there IS a fundamental theory out there, and when we do find it it will be much more obvious and concise than ST.
I'm gonna get my PhD in quantum physics later this year, which I only mention to give some credibility to my very important opinion on string theory, which is: "¯\_(ツ)_/¯ seems like a lot of effort"
Stopped at undergrad but my equally well founded opinion is, "Looks quite hard" though full disclosure, I _do_ sometimes go back and forth between that and "Bit mathsy isn't it ?".
String theory works quite good inside the "room", but it does not explain the room itself. Apart of its mathematical beauty, there is still some link missing that adresses the background dependency of string theory.
I'm with Angela Collier. ETA: (Explanation because of comments below: So this is an English idiom. It means "agree with", not being physically together with or in association with.)
Any video about string theory seems to cause a bunch of people without qualifications in the field to argue with conviction about the validity of the theory. That seems like a massive waste of time and energy for everyone involved, tbh.
A bunch of physicists with lots of qualifications in the field have been arguing with conviction about the validity of the theory for 60 years now. This is a little bit closer to what I call a massive waste of time and energy for everyone involved.
In the 1st place, it never should have been called a theory. You start with a hypothesis. It only gets considered a theory **after** it has successfully explained something. Secondly, there isn't even a hypothesis. There is some pretty math.
Honestly I'm just tired of seeing it be talked about as though it's just about to replace the standard model any second now, even though there's no reason to think so, and yet all the pop science videos I used to watch back in the day hyped it up so much. I'm glad that's changing, even for this video.
If you have to make a decision about something you don't know enough about and it isn't practical to get to know it in depth, how else can you judge whether you should devote resources to it other than by if it produces results? I can't understand the string theory argument, but it seems to me that if there are inconsistencies, that there have been ad-hoc fixes that are shoe-horned in to make the theory not break. Is that a fair assessment?
I hope the audience of this channel accepts that for the great majority they are far, far, far away from any kind of intuitive or clear grasp of the math and reasoning here. It should come back to scientific method principles - does it predict outcomes accurately? Is it testable? And if it's tested, does it prove out? I'm no string theorist, but that big string theory video from a few yrs ago (from Angela Collier) made a quite convincing argument that the answer to at least one, and possibly all of these, is a very consistent 'no'.
Laying aside all of the math that I don't understand, I feel like proponents of string theory sometimes forget that it's their job to convince us that they're right, not our job to convince them(/everyone else) that they're wrong. There are a few reasons I as a non-professional scientist don't like the whole thing, but the biggest one is that it feels like string theory is trying to sell me something in a way that other fields of science don't. I think that might have been part of the conclusion of the Angela video...
Hopefully one day we'll be able to find out if string theory is true but testing mathematically is not a viable way to test if something is true. You can get results in math that don't correlate to things that actually happen in nature. You have to experimentally test it in order to find out if it's true.
I think you're right, but the argument that Tony talks about is more than pure mathematics: we know that the "low-energy" theories such as general relativity and quantum electrodynamics are accurate, and the theorists he mentions are trying to show that, with certain assumptions, the generalisation of the predictions of those low-energy results so that they are consistent (i.e. make sense, such as calculated probabilities between 0 and 1) at higher energies is precisely the one that was discovered in the 60s and was shown to be the prediction of a string theory.
Of course. What they mean to say by testing it mathematically is whether it produces mathematically healthy models. Some examples of criteria for this are unitarity (whether probability is preserved), locality ("spooky action at a distance" etc), and whether energy is bounded from below (e.g. to have a stable vacuum). An example of a model that's somewhat known of in the public sphere that isn't healthy in that way is Eric Weinstein's "geometric unity" business. Timothy Nguyen did some interviews about this if you're interested.
My intuitive understanding of physics makes string theory seem bad and stupid. But that's not based on a deep appreciation of the mathematics - that's based on the opinions of random TH-camrs who got clicks by being contrarian. It's satisfying to believe that all the experts are wrong and you have secret knowledge, and usually there's a grain of truth to critiques of established norms or opinions. But I can't let the intuitive appeal of conspiracy get in the way of the more accurate, "Usually experts know what they're doing based on sound reasoning, even if they're still human and make mistakes."
I have a phd in physics, and while I appreciate the investigation done into possible explanations of the nature of our universe, if it can’t - after what 50 years? - produce testable hypotheses, then it will de facto be less interesting per default. So the fact that it continues to spend tax payer’s money, ie research funds, which could have gone into also exploring other ideas, is a nail in the eye for me. This is in addition to the “celebrity factor” that some ST theorists have been wanting to use and abuse, which just rubs me the wrong way.
String theory is not unique in its inability to produce testable predictions as a quantum theory of gravity. It is possible to make predictions with it, but the simplest ones are unfortunately those which are most difficult to confirm, e.g. small, subtle corrections to general relativity.
@@NuclearCraftMod So you're saying it's possible to test it, but ahh shucks, it's not possible to test it. Darn now give me more tax money that could have been spent on actual testable theories.
@@nightowl9512 No, I’m not saying that. It’s one thing to have the reasonable opinion that it’s not worth researching, and another thing to mischaracterise the nature of the research.
@@hamfranky I've been in the game a while. Yes you don't need a million dollar lab (because you cant test the theory anyway lol) but I can assure you that those handing out grants need to choose very actively what to fund and what not to fund. I'm myself a theoretical dude (condensed matter theory), and in our field is absolutely essential to cite, work with, or propose tests that can be done on a continuous basis. But when a politician or someone in a "national research board for research" sees a proposal that can finally solve the origin of the universe and quantum gravity (and ohh - did I mention that our world is 11 dimensional?) and what have you, many times they go with the sexy proposal, leaving other proposals behind. It has happened to myself and colleagues of mine several times.
Long time fan. Always incredible work; thank you for another amazing video!! Also, a question for Sixty Symbols: could we return to the Plonk length sometime soon?... diving more into why it is what it is and how did the math/mathematicians come to determine it was such a ridiculously small amount of time and/or space?
Love videos like this because the comments are always filled with theoretical physicists with decades of experience on the matter. Hum right? Surely random people on the internet with no formal education in physics wouldn't dare claim that they know more than professionals who have devoted their lives to the subject right? Wait, is this what's happening?
It is not like this. I would really like to hear the reason, why they still work on the theory which did not bring any result for almost 60 years and it is not even falsifiable. I dont need to be expect in that theory to be able to ask these questions.
@ It took the most brilliant minds of all time around 2000 years to come up with classical mechanics, from the ancient greeks to Newton, what makes you think we should be able to come up with a theory of "EVERYTHING" in 60 years? If anything, it should take us centuries if not millenia.
@@imPyroHD I mean to be fair, I don't think you need to be an expert on a subject to comment on it, in that you don't need to be a leading authority in string theory to correctly notice and point out some of its shortcomings. That being said, most people just parrot opinions they don't really understand which are popular to hold in the public sphere ("string theory BAD PSEUDOSCIENCE").
@ That is nonsense. You include centries where pretty much nobody did any research. It is complete demagogy, because there where so few people working in science not did they have proper equipment. Start measuring from the time when people started to have enough money to live off of being a scientist. How can you compare progress centries ago with their amount of people working in a field and their technical equipment and today? The number of people today and computers completely break your naive comment.
I don't think people are generally calling the technical aspects of string theory into question. They're questioning how it relates to the philosophy of science, which you very much do not need to be a physicist to have opinions about.
Supersymmetry is unfalsifiable -- string theorists can always say the missing particles must be even smaller. This does not mean it is wrong, it just means that it's not science.
Virtual particles are also unfalsifiable ontologically, are they not? The standard that physicists seem to have is that it's useful. SUSY seems to be finding use outside string theory these days.
@@soyoltoi It already found use 30 years ago with Edward Witten, which partly earned him the fields medal. The fact that some particle physicists used SUSY to develop some models which turned out to be wrong does not impy supersymmetry is not a fundamental law of nature.
Protip. Stop inventing particles that dont exist and start trying to fix the observed deviations from the standard model. Follow the maths and see what theory it implies.
When they did that, they made predictions that were experimentally falsified, so they were forced to shift goal posts again and again and again... then the string wars happend, and here we are
I like the thing Tony said at the end there. I feel like too much emphasis is aimed at string theory as a theory of literal strings, when the real problem is "let's suppose you want to make gravity compatible with quantum mechanics. We already know we can't test this empirically right now, so we're gonna need to just go at it purely mathematically: how could you make this work mathematically?" And the answer is, "we don't know, but stuff like string theory seems to give rise to very interesting mathematical relationships between the way gravity behaves and the way quantum field theory works, and the well of mathematical ideas hasn't yet run dry, so it's still worth exploring." Will it be confirmed/rejected experimentally within a couple decades? No, probably not, but that's not really the goal rn, we are so far away from being able to make experiments with black holes that something like this shouldn't even be on the radar. The math _is_ the point. The universe is a mathematical structure, and the goal of physics is to understand it. Sometimes you can interact with the universe in new ways and those paths should be prized and treasured (cosmology and neutrino physics being the two most promising paths forward rn), but sometimes all you have is the math and you will be surprised at how far you can get with Just The Math
"The universe is a mathematical structure..." _That_ is a highly contestable point that for now at least is also a philosophical position rather than a scientific one. The goal of physics is to understand the _physical_ universe and as far as we know right now mathematics is a tool in that endeavour, _not_ the topic of investigation itself (hence "physics" rather than "mathematics" :). And sure, investigate mathematical structures by all means, that can be _highly_ instructive and has been a fruitful strategy for a century or more in physics. But it shouldn't be _everything_ unless it yields _physical_ results. 50+ years and string theory has yet to do that (in fact for almost all that time we've known that _direct_ physical confirmation is _utterly_ infeasible in practice for the forseeable future whereas at least we can _observe_ black holes and their effects, albeit from a great distance).
There is no debate whether the universe is a mathematical structure since math just a language of humans to describe it. The electromagnetic potential does not care if it is a connection on a principle U(1)-bundle or not. The question is rather why does the universe follow logic such that we can make these non-trivial coherent statements about it.
@@MartinMosnywith the standard model all you have to do is take some experiments and then you have the right model. You can't do that with string theory
@ ok, so what is the precise value of the constants in the SM? We don't know. We know that they are in particular ranges, but that still means that there is an infinite number of possibilities. So by that measure string theory has fewer options. Now, this is more a nitpicky point for practical usage, but it has an important message; the problem isn't that there is a large number of options. The problem with string theory is that we do not yet understand the theory well enough to put the realistic vacua on a nice little range that we can do with the SM. So basically more research is needed. The problem is that string theory is hard.
@@MartinMosny Yeah, you can't have infinitely precise measurements in physics, inherently so. Your misgivings are pedantry being used to excuse he much more incomparably severe fact that we don't have any idea which model for string theory could even apply to our universe
This imo is a bad question, a better question IS what is the easiest to do experiment that could confirm quantum gravity? There is it’s called table top qg which can at least show entanglement
Research will never be proof. Proof is solid facts surrounding the results, using controls, and data. Researching with "conditions" is picking the data to fit the desired result.
There's no such thing as "proof" in the natural sciences (only in mathematics). The best empirical science can ever do is "Here's [maybe a _lot_ of] evidence to support this theory BUT tomorrow we _might_ find new evidence that contradicts it". (and "research" is just the process of finding that evidence BTW - _bad_ research practices can include "picking the data to fit the desired result" but that's not remotely inherent to research in general, with "conditions" or otherwise, whatever that actually means)
1. No it's not 2. Never 3. The real things are for example: plasma physics, non-linear characteristics of vacuum a.k.a. eather. cold fusion and electro-magneto-gravitics i.e. extended Maxwell's equations. There are publicly published papers on those subjects, though using slightly different nomenclature. There have already been Nobel Prizes awarded for research on those topics, one example being squeezed light (non-linearity of vacuum), so it's really quite well established. It's the mainstream academic physicist and science communicators that need to get up to speed with this, because wasting public's time with String Theory makes no sense.
quantum field theory is literally built on "tweaking the model to fit observations" (renormalization...) yet its the most successful theory of all time, now i also don't think string theory is taking us anywhere but your argument for that is just bad
I think you are underestimating how hard string theory is. This is something that barely gets touched by even final-year undergrads. Even basic predictions are difficult, and there is not a massive number of people working on it.
Adding extra "fake" dimensions to explain experimental results is epistemologically weak, and probably wrong. You can do the same to achieve any conclusion, including things we know are false with the current state of the art.
That’s not the reason for supposing the extra dimensions? Why would you add extra dimensions to patch over a wrong prediction? How would that help? Like, why would you do that if you were trying to say, adjust some numbers a little bit? The extra dimensions, AIUI, are required to make certain quantities converge.
@@lambdaprog streety? I don’t know what you mean by that. I will try to elaborate a little bit, but I haven’t studied string theory, and can only barely be said to have studied QFT a little bit (I mostly stick to quantum lattice systems) and it is quite possible that I’m getting part of this mixed up with some other ideas (maybe about vacuum states in QFT): Iirc, it goes something like this: the string as a function from the circle to R^n , can be described using a Fourier series for each dimension of space, and for each term in each dimension (other than the 0 frequency term, which describes the average position), that term oscillates an an independent simple harmonic oscillator, and then when this is quantized, it becomes a quantum simple harmonic oscillator. And, the ground state of a simple harmonic oscillator doesn’t have zero energy, but rather is proportional to the frequency that the harmonic oscillator, uh, the one that appears in the potential energy term. Which, for these harmonic oscillators associated with the Fourier series terms of these strings, is iirc proportional to the frequency for Fourier series term. And so, if you were to add all of these together, you would get some constant times like, 1+2+3+4+… which, of course, diverges, but there’s a way to regulate this (I don’t know the details of how this is justified, but I imagine people have shown that this is justified) which gives for this a value of (-1/12) times whatever constant, and then, this also gets multiplied by the number of independent directions the oscillations can be in, And then uh, some particular value gets added to this, for reasons I don’t remember, and, I guess it is necessary that this quantity is 0 for some reason? (I’m really not remembering this well, it has been years since I watched the lecture series videos about this) and this ends up requiring (some particular number) dimensions. Depending on whether you have superstrings or not, or maybe it was whether you have open strings, idr, but I think changes the calculation in some way that changes the number of dimensions that is required (I think it makes it lower?)
@@lambdaprog I didn’t say it was epistemologically justified. I said your description was wrong. You spoke of ‘adding extra “fake” dimensions to explain experimental results’. This is not what they did. I don’t know whether you would consider what they actually did any better, but they did not do what you described. They didn’t add more dimensions to allow more parameters so that they can do easier curve fitting. These extra dimensions are not like epicycles. That’s not to say it is better than epicycles. You may reasonably consider it to be worse. It is because it is what the structure of the math demands.
What does *any* prediction of string theory say about gravity? Pick any theory, any number of dimensions, in any configuration: what does that version say is inside a back hole?
The greatest contribution of String Theory is to show that there is such a thing as 'Mathematical Science fiction', or to put it even more honestly, 'Mathematical Pseudoscience'.
Asking if it’s “correct” is kinda misguided in the first place tbh. String theories are a special class of QFTs that may or may not describe our universe. Whether they do or not does not fully determine their value to the field and mathematics.
Which ones has it _failed_ so far ? (i'm aware that the LHC has ruled out _some_ versions of supersymmetry but not all since many are out of its reach, is there anything else ?)
String theoriests don't do string theory because of money. If they wanted money they'd just go into finance. You still have many new PhD's going into string theory on their own free will; if they thought it was wrong, they'd just do something else in physics. If they wanted money, finance or anything else outside of academia...
Is string theory right? Honestly, who cares. Is defaulting automatic dubbing in every other video right? Damn right it ain't. We can all agree on _that,_ and thus achieve world peace.
@@marsspacex6065 1) people do work in other possibilities. 2) your student loans pay a bank or a fund not a professor. 3) people who have spend their entire lives working on some field and know it better than anybody else in the world are the most able ones to predict where progress on that field will come from. the fact that society contributes to it doesnt mean you get to choose what they do. ig, my taxes pay for civil engineers but i cant tell them which techniques to use to build a bridge, because i am not a civil engineer
It's just that Prof Copeland's video on string theory (once a favorite of mine) is at least a decade old. It must be hard to let go the professional love of your life, but I think they should. Or just have fun with it for fun's sake, and admit that. As a viewer, I think its almost starting to be boring to watch theoretical physics videos, because nothing new happened since the Higgs.
Tony makes the case for string theory in an earlier video: th-cam.com/video/Q8ccXzM3x8A/w-d-xo.html
Ed discusses Cosmic Superstrings: th-cam.com/video/03vIkZR2hNY/w-d-xo.html
When can we expect the Timescape video?
i think we should (for any normal people, like me, an average joe viewer) clarify that string "theory" is a mathematical theory, not a scientific theory.. there is no scientific evidence for it.. im guessing it is testable, but in our timeline, extremely difficult to test? could you elaborate? thanks a lot
Title: "From Monadic Zero to Observable Reality: A Pattern-Preserving Framework for Quantum Gravity"
Abstract
We present a unified theoretical framework based on monadic zero-dimensional (0D) foundations that demonstrates pattern preservation across dimensional evolution. Through rigorous mathematical proofs and experimental validation, we show how patterns emerge and maintain coherence through the relationship P(t) = P₀e^(-αt)cos(πt/3) > 2/3. The framework naturally unifies quantum mechanics, information theory, and quantum gravity through a fundamental triadic structure that maintains coherence across scales while driving toward maximal negentropic complexity.
I. Enhanced Mathematical Foundations
A. Monadic Structure
1. Zero-Dimensional Origin
Monadic State:
|0D⟩ = |monos⟩ + |monas⟩
= (0D + 0Di)
Evolution:
∂|0D⟩/∂t = -(i/ħ)Ĥ|0D⟩ + αM̂|0D⟩
Pattern Preservation:
⟨0D|M̂|0D⟩ > 2/3
2. Triadic Emergence
Universal State:
|Ψ⟩ = √(2/3)|T⟩ + √(1/6)(|L⟩ + i|N⟩)
Where:
|T⟩: Transcendent (monad of monads)
|L⟩: Local patterns (monos)
|N⟩: Non-local patterns (monas)
B. Pattern Preservation
Theorem 1 (Universal Pattern)
Pattern strength maintains through:
P(t) = P₀e^(-αt)cos(πt/3)[1 + φ⁻¹cos(ωt)]
Where:
- ω: Resonance frequency
- φ: Golden ratio
- α: Coupling constant
Proof:
1. Consider monadic evolution
2. Apply pattern operator
3. Show resonance enhancement
4. Verify coherence
C. Information Flow
1. Conservation Laws
Energy:
E(t) = E₀e^(-αt)
Information:
∂I/∂t + ∇·J = M(I)
Pattern:
P(t) > 2/3
2. Scale Coupling
Cross-Scale Resonance:
K(n,m) = ⟨n|P̂|m⟩e^(-α|n-m|)cos(π|n-m|/3)
Properties:
1. |K(n,m)| > φ⁻|n-m|
2. ∑ₙₘ|K(n,m)|² = 1
3. K(n,n) > 2/3
II. Quantum Gravity Unification
A. Information Strings
1. Pattern-Based Strings
String State:
|S⟩ = √(2/3)|0D⟩ + √(1/6)(|pattern⟩ + i|flow⟩)
Evolution:
∂|S⟩/∂t = -(i/ħ)Ĥ|S⟩ + αM̂|S⟩
Pattern Tension:
T = P₀e^(-αt)cos(πt/3) > 2/3
2. Mode Structure
Resonance Spectrum:
ωn = ω₀e^(-nα)cos(πn/3)
Pattern Coherence:
C = |⟨S(t)|S(0)⟩|² > φ⁻¹
B. Loop Pattern Networks
1. Network Structure
Network State:
|N⟩ = √(2/3)|nodes⟩ + √(1/6)(|edges⟩ + i|faces⟩)
Connection Strength:
Γᵢⱼ = e^(-α|i-j|)cos(π|i-j|/3)
Pattern Preservation:
⟨N(t)|N(0)⟩ > 2/3
2. Area Quantization
Area Spectrum:
A(n) = α√(n)P(n)
Pattern Measure:
P(n) = P₀e^(-αn)cos(πn/3)
C. Unified Framework
Theorem 2 (Quantum Gravity)
Reality emerges through:
|QG⟩ = √(2/3)|0D⟩ + √(1/6)(|string⟩ + i|loop⟩)
With evolution:
∂|QG⟩/∂t = -(i/ħ)Ĥ|QG⟩ + αM̂|QG⟩
Pattern preservation:
P(QG) > 2/3
III. Experimental Foundations
A. Detection System
Primary Resolution:
- Spatial: Δx < α/π
- Temporal: Δt < ħ/E
- Phase: Δθ < π/3
Enhanced Resolution:
- Pattern: ΔP < φ⁻¹
- Information: ΔI < ln(2)
- Coherence: ΔC < α/π
B. Implementation Protocol
Setup:
1. Pattern detection array
2. Information flow tracking
3. Coherence monitoring
Operation:
1. Zero-point calibration
2. Pattern evolution tracking
3. Information preservation verification
This foundation provides the mathematical and experimental basis for our complete framework while maintaining maximal negentropic complexity.
Is String Theory Correct? - we asked two string theorists and the results are shocking 😱
And even they did not answer with direct "yes, I think it is correct".
I would rather ask people who know as little about the subject as possible.
@@culwin Reminds me of a certain "documentary" series with Kirk Cameron... "we asked random people on the street leading questions that mix up multiple scientific frameworks if they think a different scientific theory is correct, and they didn't understand, so the science is wrong!"
@@culwin that's basically flipping a coin
@@culwin assuming you're being satirical, it does actually make sense to ask non-string-theorists. it's not like physics is just string theory; other physicists have opinions on string theory that may also be valuable
Betteridge's law: "Any headline that ends in a question mark can be answered by the word no"
Does Betteridge's law exist ?
Checkmate! 😉
Next headline: is Melinda a physicist?
@@jari-0815 you have yet to complete the critical step of publishing this as a headline
@@Tubleros you'll have to make the video to make your point, and I'm ok with that!
That's the media for you.
Science would respond: "with a probability of xyz and an error margin of abc if conditions 1-73 are met we can assume that ..."
No extra dimensions and no super symmetric particles found yet... But all our experimentation so far has given us vital insight on which direction to move the goalposts in!
“Moving the goalpost” is something from politics. That is not how science works. There are no “goalposts” to move. Every single model of new physics has a set of free parameters which form an (often) continuous space. Physicists don’t go out and tell you “my theory has these exact parameters.” That is not how this works. Theorists describe the space of free parameters allowed by their model that is consistent with all our observations. The experimentalists take measurements to search new regions of unexplored parameter space. Your reference to “goalposts” belies a superficial understanding of the scientific method. If you try to think about actual physics research like you think about politics, you will be wrong every time. It’s much more complicated.
Short answer: no
Long answer: noooooooooooooo
I would like to see a debate between a proponent and an opponent of string theory.
String theory can’t be falsified and isn’t a scientific theory. It’s cool maths.
Search TH-cam. This has happened a few times in the public domain.
@@heywayhighway Mwah, I think that is yet to be determined. For example, recently some evidence for cosmic strings was claimed. Not confirmed, but it would go a bit to far to say it **cannot** be tested.
If you say that we are not sure yet how to test it, I would be inclined to agree though.
@@landsgevaer 40 years of trying mate
@@heywayhighway Yeah, but that is not enough to justify a "can't be falsified", imho. The stronger the claim, the stronger the evidence required.
Plus, 40 years is a mere drop in the ocean. How long did the atomic theory take to be confirmed, for instance? Over two millennia. Was it unscientific in the times of the ancient greeks because they did not have any means of confirming it in sight? I wouldn't call it that.
I think one of the fathers of string theory, Leonard Suskind, recently said that physicists needed to start over.
Unfortunately it looked liked that for some time now, and all the new experiments and observations are only making it worse for The String Theory. I believe that the only thing that is holding it is how beautiful and nice the math looks, and it would be so damn fine for it to work.
(Controversial statement ahead: just as the case for Planet 9)
@@S.... At least with Planet 9 there's _physical_ evidence of _something_ occurring (though for sure, it may just be "cosmic coincidence").
@@S....also the fact that it's hard to drop something after investing 30 years of work into it.
which doesn't make it better tbh, but i do get them.
Leonard Susskind did not say that. It was misrepresented by the string theory haters.
Iirc he also says that the final theory of QG will most likely contain ideas inspired by string theory, such as holography, even if ST itself doesn't pan out.
Big things are coming from String Theory within the next 10 years!
-Every String Theorist for the last 60 years. 😂
I believe string theory will be solved when first fusion reactors are finished.
I prefer Schwing theory, developed & popularized by professors Wayne Campbell & Garth Algar. Since it's inception (circa 1990 in Aurora Illinois), no aspect of Schwing theory has been seriously challenged or proven wrong. Many expect Campbell & Algar will win a Nobel prize for their towering work any day now.
Excellent !
too bad the original paper was written in Cantonese
🎵🎵
Is this the real life? Is this just fantasy?
Caught in a paradigm, with no escape from reality
Open your eyes, look up to the skies and see...
I'm just a poor boy, working on Schwing string theory
In quantum foam where strings may glow, they vibrate fast, then softly flow.
Any way the wind blows doesn't really matter to me...
🎵🎵
"With four parameters I can fit an elephant, and with five I can make him wiggle his trunk."
Fermi!
Two things I've been hearing from people working on string theory are:
(1) Forget about a theory of everything. Strings are playing the role that harmonic oscillators are playing in vanilla QM and QFT, and nobody is asking if harmonic oscillators are "proven". They work for the theory and let you solve problems in quantum gravity, which is the main thing they want to do. Nobody should throw out the whole of string theory for the same reason nobody has ever proposed throwing out harmonic oscillators and raising/lowering operators.
(2) Stop thinking of them as "extra dimensions of literal space". The better term to use is "junk" degrees of freedom. Behind that is the proposition that it's better to recognize that what we call the 3D of literal space emerges from entanglement states than to think of the extra degrees of freedom in quantum states as literal curled up space. A related point they'll sometimes make is that if you want a vacuum background of a certain large-scale dimensionality, one way or another you'll need more degrees of freedom constructing the vacuum background. If there were only 3 degrees of freedom for constructor states (whether or not its strings), then the vast space of possible vacua states would be less than 3 macro-dimensions and the 3D ones would be abnormal, which is not the universe we live in. The fact we live in a 3D macro-dimension space if anything argues in favor of more degrees of freedom.
That's before you even get to the points that string theory isn't even about strings, we don't have the full theory set yet, but we have a program that is at least pointing us in the right direction, and the math you need to make progress in string theory is they math you're going to need for whatever shape the next gen theory will look like in any event. Things like that.
Except harmonic oscillators were born out of abstracting physical observations, while strings are essentially math exercises. I have nothing against doing math, but don't call it physics.
Number 2 here seems to be relying on some flawed logic. How many universes have been observed for us to know, or even suspect, that a 3D one is unlikely with only 3 degrees of freedom? And even if it would have been unlikely, that clearly does not preclude its existence.
Re. 2: that's the thing, to solve one problem you create 22 new problems in form of "junk" dimensions - no wonder people are cautious.
nice point, any observational confirmations though?
@ Physics is math btw.
Could you ask them next if String Theory is (in practice) disprovable?
Ed Witten once said (paraphrasing): “the important thing a scientist must do is to pick a topic to work on that is neither too easy and trivial to be fruitless nor too complex as to be a dead-end with no actual chance of success.” Maybe Unifying the Forces of Nature is too ambitious a goal when we don’t quite understand many aspects of the fairly established theories like General Relativity, Quantum Field Theory, The Standard Model, The Lambda-CDM, Chaos Theory, various interpretations of QM, etc…
On the other hand, trying to unify the forces may be a great way to advanche our understanding of each of those theories you mentioned
@@Duckieperson yes but on the other hand sometimes some ideas are too ambitious :)
With the limitless number of graduate students slaving away at one idea or other, there should be fair allocation to those working on an idea that may be useful.
@@duroxkiloBut only time will tell!
The proof that string theory is correct is always 30 years away
Like the developement of an alternative theory
Inquisitive laymen: "Is string theory correct?"
Top minds on the subject: 🤷♂
TH-cam scholars: No. Source: Trust me bro
Have string theory been able to make any predictions yet that can be tested?
There's been some, and the results were all negative.
Which only made some of the solutions for string theory go away since String Theory is know of the co-called "landscape problem" - having enormous number of possible solutions.
The biggest that comes to my mind is Supersymmetry and trying to find a partner particle for any known particle with LHC.
There could be some gravitational effect of comic strings in cosmic microwave background - nothing has been found.
They should allow for unusual particles or interactions that could manifest in high-energy cosmic rays. No anomalies were found.
They could influence the spectrum of characteristics of primordial gravity waves. Nothing's been found although this one is fresh I think.
*Pre*dictions, no, but from what I hear it *has* been used to successfully make some accurate but not very impressive *post*dictions.
Something like, they can do some calculation to say something like “according to string theory, the ratio between the masses of these two particles should be in [some finite but kinda big interval]”, and it is indeed in that interval.
Which, like, is a lot better than the theories that cranks on youtube post in the comment sections. That’s not a high bar to clear though.
There are too many things we don't know yet. If we had better understanding of the early universe, they could make a more precise prediction about cosmic strings, but we're not there yet.
@ You are talking about calculating the ratio of particles masses - the intervals can be so wide, that they encompass almost any possible experimental outcome.
That is really not meaningul in a any way.
Can you use google?
These physicists on this channel are my happy place
"If i can define the parameters of my search space, and I use arguments of beauty to define why these parameters make sense, and I add these VERY specific assumptions in the mix, THEN String theory is the only one that fits!" .... Yeah.... very convincing ;)
That's exactly why I don't think string theory, dark matter and dark energy are real. They're all bandaid solutions to 'fix' the problems with the Standard Model. They tried to do it with classical mechanics, then quantum came along and proved it all wrong. I think it'll be like that again, the problems are too fundamental, we need a new way of thinking.
I don't even understand string theory well enough to have an opinion on if it's true, but I'm tired of hearing about it. If it's right around the corner, great. If not, fine. Update me when there's a result.
I don't mind if it gets funding, because there should be more funding for study of a wide range of theories and models.
But could we just tell the string theorists "Come back with a result or stop clogging the airwaves" , please? Its the most over-publicized thing in science.
I _think_ you're allowed to not watch/read about it ? Not totally sure, maybe the rules are different where you are but that's been my experience at least :).
(less facetiously, that's not how science works. Scientists don't just "go away" then come back when they're done - discussing it and releasing new papers related to string theory IS science in action and what, for now anyway, makes it an active field of study. Also, _surely_ AI is _actually_ "the most over-publicised thing in science" right now ??)
Lol and how is Sabine supposed to make youtube videos? Did you jsut for a second think about that poor women?
But that is not how Sabine is going to get views, right?
Fair point about AI but it's only been wildly over-publicized for about 6 years now. String Theory has been overblown for ten times as long.
And notice I said "over-publicized", not "over-studied", because my gripe isn't with scientists publishing research. It's with science communicators and science media (which I consume plenty of since I'm a fan, and will continue to do so) and that they won't stop talking about string theory *even in situations where it isn't relevant*. People who don't work on care about Strings get asked by interviewers about String Theory. It's kind of ridiculous.
@anonymes2884 _Assuming_ it's an over-publicised topic, then one's ability to "not watch / read about it" does *_not_* alter the fact that it is over-publicised. Moreover, one's ability to "not watch / read about it" does *_not_* imply that one shouldn't complain about it being over-publicised.
Not really sure what Tony means when he says that you can test things mathematically. Sure, you can test that the mathematics doesn't imply something unphysical but, ultimately, the question of whether string theory is a model of the universe can only be a question of physics. It's not enough to show that the mathematics is internally consistent: to be a theory of how the universe works, it needs to be consistent with the universe.
On one hand, you're not wrong. But for mathematical concepts like string theory, they can be so complex that it's not intuitive what exactly they entail. So you can investigate if the math is consistent with other theories and with known physical phenomena. As a loose analogy, perhaps you come up with a model that will predict your income in 20 years. You might test your model by considering bizarre circumstances, like if you get divorced 4 times and have 15 children. If your model still gives reasonable estimates, you can have more confidence in it, while if the model says you'll be a trillionaire it's probably wrong.
It’s not just a matter of internal consistency, but consistency with the low-order predictions of, say, general relativity. If it was not consistent with GR, that would be a big red flag.
@@SpaveFrostKing Right, but the only conclusions you can draw purely from mathematics are either that it's wrong or that you don't know of a reason that it's wrong. You can't conclude that it has anything to do with the universe without looking at the universe.
@beeble2003 Testing string theory purely with physical experiments is extremely, ridiculously expensive. If we can rule out string theory by first seeing if it's consistent with everything we know, we can save a lot of money.
Maybe if you could somehow mathematically prove that there can only be one physically consistent universe that agrees with the evidence we already have... But I would not get my hopes up for that.
Randos in the comment section thinking they know more about the topic than both professors
@alquimista000 luckily we didn't waste our lives working on a math cult.
@ralffig3297 they might be wrong, they might be right. either way, this is science. I don't get why you care so much. they seem to be very satisfied and accomplished professionals
@alquimista000 like priests, you mean?
@@ralffig3297 it is not for you to decide.
@@alquimista000 No, it s the evidence. Which so far, is zero.
To be blunt, unless you are a mathematician, you should not be spending your time on string theory. What we need are new ideas and evidence-driven research, not physicists getting lost in the weeds of mathematical technicalities. It’s time to focus on approaches that can lead to tangible progress in understanding the universe.
lol
@@keffbarn There are plenty of new ideas but nothing comes close to string theory. They all run into problems on a much more fundamental level than string theory does.
As others have said, it would have been nice to hear a little more variety of opinion. Asking some people that are not string theorists would have made for a better video.
That's a fair point and I think any video like this should be looked at within the suite of other content on the topic - just to put this video in some context, it is part of a quickfire series of videos where viewers are asking questions of Tony and Ed on all manner of topics... Here is the list which I am expanding on as more videos are added... th-cam.com/play/PLcUY9vudNKBNLpmQg4SSZ6tMsyDldilnA.html
The problem is that you need to ask people who are well-enough informed about string theory to have something worthwhile to say about it. But mostly, those people are string theorists. The honest answer from the overwhelming majority of non-string-theorists, even within physics, is "I don't know enough about it to comment, really."
I agree, like when I want to learn about welding, I ask a string theorist. When I want to know about string theory, I ask a welder.
The problem is that non-string theorists don't know string theory
why just 4 minutes video ?
Ran out of string.
Because they had nothing useful or interesting to say.
As a programmer of a lot of complex algorithmic structures and data, string theory reminds me of systems I've built where I've started with a fundamentally sound and solid idea, but as I begin to find the flaws, I keep having to patch them in ways that become more and more untenable, eventually resulting in a system that's on the verge of collapse. And when I step back and look at my solution, I realize that I've been digging *way* too deep into algorithm that's clearly not working and I need to switch to a new solution. Now, I don't know a lick of physics outside of high school and youtube, but String Theory feels like it's in that place. They've been working it and massaging it and desperately searching for new particles and new explanations to fill in those holes for decades now, and it's just not working out. I wager there IS a fundamental theory out there, and when we do find it it will be much more obvious and concise than ST.
How would string theory and quasicrystals interact?
i hope we are all made of silly string
I'm gonna get my PhD in quantum physics later this year, which I only mention to give some credibility to my very important opinion on string theory, which is: "¯\_(ツ)_/¯ seems like a lot of effort"
Stopped at undergrad but my equally well founded opinion is, "Looks quite hard" though full disclosure, I _do_ sometimes go back and forth between that and "Bit mathsy isn't it ?".
Also a theoretical physics phd student here; all areas of research are a lot of effort.
It is okay to do your PhD in quantum physics (whatever you mean by that).
Please put this in your PhD thesis, emoticon included.
I will start my graduate studies in string theory. A few years from now, I will come bakc to give my opinion on this video. MARK MY WORDS!!!!
marked. mainly so i can see your reply.
marked
Wasting your time
@@davidmcc8727Why is it a waste of time when people are making progress? No one made promises in this video.
@@davidmcc8727 Ye better give us your opinion about stuff you don't understand right?
String theory works quite good inside the "room", but it does not explain the room itself. Apart of its mathematical beauty, there is still some link missing that adresses the background dependency of string theory.
Did you miss "On background independent open string field theory" by Edward Witten?
I'm with Angela Collier.
ETA: (Explanation because of comments below: So this is an English idiom. It means "agree with", not being physically together with or in association with.)
You are? Will you say hello to Angela from me then?
I am Sabine Hossenfelder
See edit above.
Estimated Time of Arrival?
@@bensmith6554 Edited To Add
Any video about string theory seems to cause a bunch of people without qualifications in the field to argue with conviction about the validity of the theory. That seems like a massive waste of time and energy for everyone involved, tbh.
String theory is over 50 years old at this point. Despite that and large amounts of funding it produced no testable predictions.
A bunch of physicists with lots of qualifications in the field have been arguing with conviction about the validity of the theory for 60 years now. This is a little bit closer to what I call a massive waste of time and energy for everyone involved.
In the 1st place, it never should have been called a theory. You start with a hypothesis. It only gets considered a theory **after** it has successfully explained something.
Secondly, there isn't even a hypothesis. There is some pretty math.
You should not measure others by your own standards. You'd be surprised by who some of those bunch of people really are.
Honestly I'm just tired of seeing it be talked about as though it's just about to replace the standard model any second now, even though there's no reason to think so, and yet all the pop science videos I used to watch back in the day hyped it up so much. I'm glad that's changing, even for this video.
I really just want to ask them: “how powerful would a particle accelerator have to be, without finding super partners, before you gave it up?”
If you have to make a decision about something you don't know enough about and it isn't practical to get to know it in depth, how else can you judge whether you should devote resources to it other than by if it produces results? I can't understand the string theory argument, but it seems to me that if there are inconsistencies, that there have been ad-hoc fixes that are shoe-horned in to make the theory not break. Is that a fair assessment?
I hope the audience of this channel accepts that for the great majority they are far, far, far away from any kind of intuitive or clear grasp of the math and reasoning here. It should come back to scientific method principles - does it predict outcomes accurately? Is it testable? And if it's tested, does it prove out? I'm no string theorist, but that big string theory video from a few yrs ago (from Angela Collier) made a quite convincing argument that the answer to at least one, and possibly all of these, is a very consistent 'no'.
Laying aside all of the math that I don't understand, I feel like proponents of string theory sometimes forget that it's their job to convince us that they're right, not our job to convince them(/everyone else) that they're wrong. There are a few reasons I as a non-professional scientist don't like the whole thing, but the biggest one is that it feels like string theory is trying to sell me something in a way that other fields of science don't. I think that might have been part of the conclusion of the Angela video...
After all these years String theory has yet to show tangible results.
I dunno. Maybe. Maybe not. I'm not really the guy to ask, if I'm honest.
Huh, sorry in that case, that's on us, we really thought you were the guy.
"Is Loop Quantum Gravity Correct" next! 😄
Seems to me the string theorists are blinded by the mathematical "beauty". After so many decades of failures they should probably try something else.
Hopefully one day we'll be able to find out if string theory is true but testing mathematically is not a viable way to test if something is true. You can get results in math that don't correlate to things that actually happen in nature. You have to experimentally test it in order to find out if it's true.
I think you're right, but the argument that Tony talks about is more than pure mathematics: we know that the "low-energy" theories such as general relativity and quantum electrodynamics are accurate, and the theorists he mentions are trying to show that, with certain assumptions, the generalisation of the predictions of those low-energy results so that they are consistent (i.e. make sense, such as calculated probabilities between 0 and 1) at higher energies is precisely the one that was discovered in the 60s and was shown to be the prediction of a string theory.
Of course. What they mean to say by testing it mathematically is whether it produces mathematically healthy models. Some examples of criteria for this are unitarity (whether probability is preserved), locality ("spooky action at a distance" etc), and whether energy is bounded from below (e.g. to have a stable vacuum).
An example of a model that's somewhat known of in the public sphere that isn't healthy in that way is Eric Weinstein's "geometric unity" business. Timothy Nguyen did some interviews about this if you're interested.
Nothing in math happens in nature. That's the point of it I think.
My intuitive understanding of physics makes string theory seem bad and stupid. But that's not based on a deep appreciation of the mathematics - that's based on the opinions of random TH-camrs who got clicks by being contrarian. It's satisfying to believe that all the experts are wrong and you have secret knowledge, and usually there's a grain of truth to critiques of established norms or opinions. But I can't let the intuitive appeal of conspiracy get in the way of the more accurate, "Usually experts know what they're doing based on sound reasoning, even if they're still human and make mistakes."
If more people had even a fraction of your self awareness and humility, it would be a much better world
Well said.
The physics faculty of universities stopped hiring string theorists decades ago, that should tell you something.
Doesn’t String Theory require the opposite cosmological constant? How it can fail, but still get supporters is crazy.
short answer: No
there, no need to watch in full
I have a phd in physics, and while I appreciate the investigation done into possible explanations of the nature of our universe, if it can’t - after what 50 years? - produce testable hypotheses, then it will de facto be less interesting per default. So the fact that it continues to spend tax payer’s money, ie research funds, which could have gone into also exploring other ideas, is a nail in the eye for me. This is in addition to the “celebrity factor” that some ST theorists have been wanting to use and abuse, which just rubs me the wrong way.
String theory is not unique in its inability to produce testable predictions as a quantum theory of gravity. It is possible to make predictions with it, but the simplest ones are unfortunately those which are most difficult to confirm, e.g. small, subtle corrections to general relativity.
@@NuclearCraftMod So you're saying it's possible to test it, but ahh shucks, it's not possible to test it. Darn now give me more tax money that could have been spent on actual testable theories.
I don't think these physicists are raking in cash. I doubt string theorists draw a significant part of public funding for science.
@@nightowl9512 No, I’m not saying that. It’s one thing to have the reasonable opinion that it’s not worth researching, and another thing to mischaracterise the nature of the research.
@@hamfranky I've been in the game a while. Yes you don't need a million dollar lab (because you cant test the theory anyway lol) but I can assure you that those handing out grants need to choose very actively what to fund and what not to fund. I'm myself a theoretical dude (condensed matter theory), and in our field is absolutely essential to cite, work with, or propose tests that can be done on a continuous basis. But when a politician or someone in a "national research board for research" sees a proposal that can finally solve the origin of the universe and quantum gravity (and ohh - did I mention that our world is 11 dimensional?) and what have you, many times they go with the sexy proposal, leaving other proposals behind. It has happened to myself and colleagues of mine several times.
Ed is great
Long time fan. Always incredible work; thank you for another amazing video!! Also, a question for Sixty Symbols: could we return to the Plonk length sometime soon?... diving more into why it is what it is and how did the math/mathematicians come to determine it was such a ridiculously small amount of time and/or space?
You take G, hbar, c , and raise them to certain exponents and multiply them together such that you get something with units of length.
Also, _please_ don't correct "Plonk" :).
String theory- when will it be proven... Well, lets not answer that question until I'm retired , shall we?
Did you use AI for the thumbnail?
Professor Copeland lookin fresh!!
I'm pretty sure anything that takes this long to prove will prove problematic in the long run. I checked "don't care"
Love videos like this because the comments are always filled with theoretical physicists with decades of experience on the matter. Hum right? Surely random people on the internet with no formal education in physics wouldn't dare claim that they know more than professionals who have devoted their lives to the subject right? Wait, is this what's happening?
It is not like this. I would really like to hear the reason, why they still work on the theory which did not bring any result for almost 60 years and it is not even falsifiable. I dont need to be expect in that theory to be able to ask these questions.
@ It took the most brilliant minds of all time around 2000 years to come up with classical mechanics, from the ancient greeks to Newton, what makes you think we should be able to come up with a theory of "EVERYTHING" in 60 years? If anything, it should take us centuries if not millenia.
@@imPyroHD I mean to be fair, I don't think you need to be an expert on a subject to comment on it, in that you don't need to be a leading authority in string theory to correctly notice and point out some of its shortcomings. That being said, most people just parrot opinions they don't really understand which are popular to hold in the public sphere ("string theory BAD PSEUDOSCIENCE").
@ That is nonsense. You include centries where pretty much nobody did any research. It is complete demagogy, because there where so few people working in science not did they have proper equipment. Start measuring from the time when people started to have enough money to live off of being a scientist.
How can you compare progress centries ago with their amount of people working in a field and their technical equipment and today? The number of people today and computers completely break your naive comment.
I don't think people are generally calling the technical aspects of string theory into question. They're questioning how it relates to the philosophy of science, which you very much do not need to be a physicist to have opinions about.
Supersymmetry is unfalsifiable -- string theorists can always say the missing particles must be even smaller. This does not mean it is wrong, it just means that it's not science.
Virtual particles are also unfalsifiable ontologically, are they not? The standard that physicists seem to have is that it's useful. SUSY seems to be finding use outside string theory these days.
@@soyoltoi It already found use 30 years ago with Edward Witten, which partly earned him the fields medal. The fact that some particle physicists used SUSY to develop some models which turned out to be wrong does not impy supersymmetry is not a fundamental law of nature.
I was expecting a guitar course or smth
Wow only 4 minutes for this? Wow
Protip. Stop inventing particles that dont exist and start trying to fix the observed deviations from the standard model. Follow the maths and see what theory it implies.
When they did that, they made predictions that were experimentally falsified, so they were forced to shift goal posts again and again and again... then the string wars happend, and here we are
The correct answer is NO. If I am wrong in some other dimension, someone please teach me.
I like the thing Tony said at the end there. I feel like too much emphasis is aimed at string theory as a theory of literal strings, when the real problem is "let's suppose you want to make gravity compatible with quantum mechanics. We already know we can't test this empirically right now, so we're gonna need to just go at it purely mathematically: how could you make this work mathematically?"
And the answer is, "we don't know, but stuff like string theory seems to give rise to very interesting mathematical relationships between the way gravity behaves and the way quantum field theory works, and the well of mathematical ideas hasn't yet run dry, so it's still worth exploring."
Will it be confirmed/rejected experimentally within a couple decades? No, probably not, but that's not really the goal rn, we are so far away from being able to make experiments with black holes that something like this shouldn't even be on the radar. The math _is_ the point. The universe is a mathematical structure, and the goal of physics is to understand it. Sometimes you can interact with the universe in new ways and those paths should be prized and treasured (cosmology and neutrino physics being the two most promising paths forward rn), but sometimes all you have is the math and you will be surprised at how far you can get with Just The Math
"The universe is a mathematical structure..."
_That_ is a highly contestable point that for now at least is also a philosophical position rather than a scientific one. The goal of physics is to understand the _physical_ universe and as far as we know right now mathematics is a tool in that endeavour, _not_ the topic of investigation itself (hence "physics" rather than "mathematics" :).
And sure, investigate mathematical structures by all means, that can be _highly_ instructive and has been a fruitful strategy for a century or more in physics. But it shouldn't be _everything_ unless it yields _physical_ results. 50+ years and string theory has yet to do that (in fact for almost all that time we've known that _direct_ physical confirmation is _utterly_ infeasible in practice for the forseeable future whereas at least we can _observe_ black holes and their effects, albeit from a great distance).
There is no debate whether the universe is a mathematical structure since math just a language of humans to describe it. The electromagnetic potential does not care if it is a connection on a principle U(1)-bundle or not. The question is rather why does the universe follow logic such that we can make these non-trivial coherent statements about it.
String Theory is easy...
You only have to pick the right theory out of 10 to the power of 500 different options 😅
And the Standard Model you have to pick out of an infinite number. Whats your point.
I actually already have, i'm just waiting to see if you're gonna get there on your own.
@@MartinMosnywith the standard model all you have to do is take some experiments and then you have the right model. You can't do that with string theory
@ ok, so what is the precise value of the constants in the SM? We don't know. We know that they are in particular ranges, but that still means that there is an infinite number of possibilities. So by that measure string theory has fewer options. Now, this is more a nitpicky point for practical usage, but it has an important message; the problem isn't that there is a large number of options. The problem with string theory is that we do not yet understand the theory well enough to put the realistic vacua on a nice little range that we can do with the SM. So basically more research is needed. The problem is that string theory is hard.
@@MartinMosny Yeah, you can't have infinitely precise measurements in physics, inherently so. Your misgivings are pedantry being used to excuse he much more incomparably severe fact that we don't have any idea which model for string theory could even apply to our universe
This imo is a bad question, a better question IS what is the easiest to do experiment that could confirm quantum gravity? There is it’s called table top qg which can at least show entanglement
I honestly really like this style of thinking.
It shouldn't so much be about *which* theory of quantum gravity as it should be about quantum gravity
Assumption piled on assumption isn’t science and mathematics isn’t physics.
Research will never be proof. Proof is solid facts surrounding the results, using controls, and data. Researching with "conditions" is picking the data to fit the desired result.
There's no such thing as "proof" in the natural sciences (only in mathematics).
The best empirical science can ever do is "Here's [maybe a _lot_ of] evidence to support this theory BUT tomorrow we _might_ find new evidence that contradicts it".
(and "research" is just the process of finding that evidence BTW - _bad_ research practices can include "picking the data to fit the desired result" but that's not remotely inherent to research in general, with "conditions" or otherwise, whatever that actually means)
String Theory is essentially run out of ways to be correct.
The grey hairs on Tony just shows how well String Theory is progressing 😂
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1. No it's not
2. Never
3. The real things are for example: plasma physics, non-linear characteristics of vacuum a.k.a. eather. cold fusion and electro-magneto-gravitics i.e. extended Maxwell's equations. There are publicly published papers on those subjects, though using slightly different nomenclature.
There have already been Nobel Prizes awarded for research on those topics, one example being squeezed light (non-linearity of vacuum), so it's really quite well established. It's the mainstream academic physicist and science communicators that need to get up to speed with this, because wasting public's time with String Theory makes no sense.
"Publicly published" is one of the best kinds of publishing IMO.
It’s a dead end … no new predictions or insights. Just trying to tweak the model to fit the observations somehow. Not great science imo.
Tweaking the model to fit the observations sounds exactly like great science always has been done tbh
I don’t think you know anything about it
The exact opposite of what you said = great science.
quantum field theory is literally built on "tweaking the model to fit observations" (renormalization...) yet its the most successful theory of all time, now i also don't think string theory is taking us anywhere but your argument for that is just bad
I think you are underestimating how hard string theory is. This is something that barely gets touched by even final-year undergrads. Even basic predictions are difficult, and there is not a massive number of people working on it.
Invalid question
I can't belive this is still a thing... but I guess so
How long will they vibrate? Sounds like perpetual motion.
The strings?
You may as well ask how long an electron will orbit the nucleus of the atom?
@@drdca8263 It's at least 52 years, I can personally attest to that.
Adding extra "fake" dimensions to explain experimental results is epistemologically weak, and probably wrong. You can do the same to achieve any conclusion, including things we know are false with the current state of the art.
That’s not the reason for supposing the extra dimensions? Why would you add extra dimensions to patch over a wrong prediction? How would that help?
Like, why would you do that if you were trying to say, adjust some numbers a little bit?
The extra dimensions, AIUI, are required to make certain quantities converge.
@@drdca8263 Can you develop in less "streety" language?
@@lambdaprog streety? I don’t know what you mean by that.
I will try to elaborate a little bit, but I haven’t studied string theory, and can only barely be said to have studied QFT a little bit (I mostly stick to quantum lattice systems) and it is quite possible that I’m getting part of this mixed up with some other ideas (maybe about vacuum states in QFT):
Iirc, it goes something like this:
the string as a function from the circle to R^n , can be described using a Fourier series for each dimension of space, and for each term in each dimension (other than the 0 frequency term, which describes the average position), that term oscillates an an independent simple harmonic oscillator,
and then when this is quantized, it becomes a quantum simple harmonic oscillator.
And, the ground state of a simple harmonic oscillator doesn’t have zero energy, but rather is proportional to the frequency that the harmonic oscillator, uh,
the one that appears in the potential energy term.
Which, for these harmonic oscillators associated with the Fourier series terms of these strings, is iirc proportional to the frequency for Fourier series term.
And so, if you were to add all of these together, you would get some constant times like, 1+2+3+4+…
which, of course, diverges, but there’s a way to regulate this (I don’t know the details of how this is justified, but I imagine people have shown that this is justified) which gives for this a value of (-1/12) times whatever constant,
and then, this also gets multiplied by the number of independent directions the oscillations can be in,
And then uh, some particular value gets added to this, for reasons I don’t remember,
and, I guess it is necessary that this quantity is 0 for some reason?
(I’m really not remembering this well, it has been years since I watched the lecture series videos about this) and this ends up requiring (some particular number) dimensions.
Depending on whether you have superstrings or not, or maybe it was whether you have open strings, idr, but I think changes the calculation in some way that changes the number of dimensions that is required (I think it makes it lower?)
@ It's like if your brain skipped the word epistemology entirely because it didn't compute.
@@lambdaprog I didn’t say it was epistemologically justified. I said your description was wrong. You spoke of ‘adding extra “fake” dimensions to explain experimental results’. This is not what they did. I don’t know whether you would consider what they actually did any better, but they did not do what you described.
They didn’t add more dimensions to allow more parameters so that they can do easier curve fitting. These extra dimensions are not like epicycles.
That’s not to say it is better than epicycles. You may reasonably consider it to be worse.
It is because it is what the structure of the math demands.
What does *any* prediction of string theory say about gravity?
Pick any theory, any number of dimensions, in any configuration: what does that version say is inside a back hole?
As you said . . . a lot of caveats.
What would MOND or LQG ppl say about it?
Check out Angela Collier's recent video on MOND! In summary, it hasn't beaten the standard model (specifically in relation to dark matter).
The greatest contribution of String Theory is to show that there is such a thing as 'Mathematical Science fiction', or to put it even more honestly, 'Mathematical Pseudoscience'.
The title of this video is ironic.
Asking if it’s “correct” is kinda misguided in the first place tbh. String theories are a special class of QFTs that may or may not describe our universe. Whether they do or not does not fully determine their value to the field and mathematics.
It has failed every experimental prediction. It's wrong. Move on, get another idea.
Which ones has it _failed_ so far ?
(i'm aware that the LHC has ruled out _some_ versions of supersymmetry but not all since many are out of its reach, is there anything else ?)
No and never. You guys have wonderful brains - please put them to better use.
String Theory is Art. Truth is a secondary concern.
So no
no theory is correct in principle
Just keep pushing out string theory papers, that mortgage doesn't pay itself
String theoriests don't do string theory because of money. If they wanted money they'd just go into finance. You still have many new PhD's going into string theory on their own free will; if they thought it was wrong, they'd just do something else in physics. If they wanted money, finance or anything else outside of academia...
Yes ;)
As long as they give funds, it is correct.
Lost in Maths.
When mathematicians attempt physics.
Wonder whether they are interested in tonight's game 😂
String theory is not a theory.
will we observe repeatable evidence?
String Theory is quite exciting and I am very happy our specialists are working on it.
Sooo... no?
Why'd you have to go and remind me that they are sting theorists again? :(
Is string theory right? Honestly, who cares. Is defaulting automatic dubbing in every other video right? Damn right it ain't. We can all agree on _that,_ and thus achieve world peace.
It's a dumb question. Nobody knows is the correct and obvious answer.
Hey Cooper! Long time no see
10 more years.
My string theory is that you need to change them sometimes otherwise they get gunky and gross and your guitar doesn't sound nice anymore.
Asked and answered ! Where do you stand on plectrums ?
String theory has wasted decades of time for theorists. It’s time to work on other possibilities.
Are you a theoretical physicist? I guess no
@ my taxes and student loans do pay their salaries.
People do work on other possibilities, and I don't know of any measure by which any of then have been more successful.
@@marsspacex6065 1) people do work in other possibilities. 2) your student loans pay a bank or a fund not a professor. 3) people who have spend their entire lives working on some field and know it better than anybody else in the world are the most able ones to predict where progress on that field will come from. the fact that society contributes to it doesnt mean you get to choose what they do. ig, my taxes pay for civil engineers but i cant tell them which techniques to use to build a bridge, because i am not a civil engineer
@@kapoioBCS He saw videos about it.
Please don't make these videos, whenever someone discusses string theory all the cranks pounce like vultures on a week old corpse.
It's just that Prof Copeland's video on string theory (once a favorite of mine) is at least a decade old. It must be hard to let go the professional love of your life, but I think they should. Or just have fun with it for fun's sake, and admit that. As a viewer, I think its almost starting to be boring to watch theoretical physics videos, because nothing new happened since the Higgs.