Is string theory still worth exploring? | Roger Penrose and Eric Weinstein battle Brian Greene

the problem is is that the the invective that was leveled from your community towards the other communities is the part that's ignored [Music] obviously a large community of thousand researchers is going to have a big bell curve of those who are able to play well with others and those who don't oh [Music] I mean the trouble is that they claim it's such a beautiful Theory as far as I can see it's a great mess I mean you've got the wrong number of space dimensions you've got an argument to try and argue that you you don't get enough energy to excite the extra Dimension and I think that argument is wrong actually because the amount of energy is for the entire universe it's not just your building accelerator it seek get up to a certain energy if it's beyond the level of that accelerator that's not the point you've got that much energy and all over the universe things with great deal of energy and there's no reason why these shouldn't excite these extra Dimensions I think there's just a misconception in that um I don't want to go into it further but it's a bit technical but I think it's a misconception and in a certain sense there are too many theoretical physics communities which have wasted their time on this area rather than doing what I regard as more interesting topics even the question of quantum gravity which has been brought up here bringing quantum mechanics and gravitational Theory together sure that's that's a very important thing to do but quantizing gravity in my view okay it's an interesting exercise but it's not the important thing in bringing them together the important thing to get and bring them together in my view is to explain why quantum theory Works see quantum theory works for tiny little things if you like but when you do what's called making a measurement or you think talk about big things it doesn't work so String Theory does not at the moment answer the question of the quantum measurement problem and I agree with Roger that that's a critical question that has faced quantum mechanics really since its Inception so I agree that there are open questions that even String Theory as it's currently formulated doesn't doesn't address has Roger addressed it with his approach that aspects of general relativity will be vital to the collapse of the wave function it's a powerful and interesting idea I've studied it I'm not yet convinced of it but it is among many ideas that people were working in this Arena have put forward I'm glad that people are working on this key question of quantum mechanics but in terms of the importance of quantizing gravity I would take a somewhat different perspective than Rogers quantum mechanics is an established part of the way the world Works general relativity is an established part of the way the world works if they can't play together if when you combine them you get nonsensical results which was the state of play before String Theory gave us a potential solution then your physical description of the world is fundamentally inconsistent and I don't think the universe is inconsistent and therefore it is vital that we find a way to put the pillars of our previous understanding into harmony with one another Eric mentioned perhaps there are other ways of doing it fantastic I'm open to those ideas but String Theory at least is one approach that does that and it's important it's vital and string theory not only achieves it but to the question of beauty let me just put forward the following you do quantum mechanics of a string without any knowledge of general relativity and just through the process of studying that quantum mechanical description of a string general relativity emerges it's forced upon you it comes right out of the mathematics if Einstein hadn't discovered general relativity strength there is studying the quantum mechanical motion of string would have found general relativity within the formulation itself that's beautiful that's breathtaking this is really weird the post addiction of general relativity uh let me do general relativity for you take the scalar curvature and integrate it okay that rediscovers general relativity in terms of taking the LaGrange equations and it took under five seconds this is not a fair way to go about things we're now having the conversation about beauty and ugliness a giraffe is beautiful as is a three-year-old child and if I cut the head off a three-year-old child and so on the head of a giraffe that is in some sense beautiful in two separate ways if I take space time and I put a collabi out threefold uh complex threefold at every point that has the feeling of a baby with the head of a giraffe there's a certain way in which it's beautiful particularly at the level of the analytics so what I hear Roger talking about very often with Twisters is a much more algebraic and geometric view what I hear Brian talking about is beauty is the beauty of a renormalizable spin 2 field that's massless falling out of the quantization of a string these are different worlds they're sewn together in a very unconvincing and ugly way uh we I don't want to Rob Brian of the claim that there's Beauty because there's tons of Beauty in the theory there's also tons of ugliness and artificiality in the theory as there is in general relativity where the equations in the lagrangian are beautiful but the energy constrain grants are ugly and have a different origin are meant to keep Einstein out of trouble so what we have is a situation in which I feel like the audience never actually hears a debate about the underlying nature and we stay on the surface level where we're talking about it's beautiful it's ugly it post-dicks it predicts this the real nitty-gritty of this thing is is that Brian and Roger are both correct and they're not coming to loggerheads in front of an audience for reasons that actually Escape me I was trying to say that all these extra dimensions are wrong and that's fundamental to the theory surely that's the log ahead if I ever thought of them isn't that a loggerhead it's a very polite loggerhead maybe um no I mean it's it's completely against the way the string theory is gone I mean originally when I heard the idea of string theory in the space time had the right number of dimensions three space and one time I thought it was a really nice idea and it seemed to indicate that things could be finite which would otherwise give you divergences and so on brings in beautiful ideas of Riemann surfaces and Mathematics which I like I like the idea I thought this is a great place to go but then they decided look it doesn't work unless you have 26 dimensions so I said okay you can work on that I'm working on real physics I mean you the reason that they present that these extra Dimensions you have to to excite all these degrees of freedom I think that argument is not correct to have a theory which involves a space which has more dimensions the number of extra parameters is infinite I mean it's it's not like adding an extra parameter in the theory if you consider the mass of the material making up the Large Hadron Collider there's enough energy there to excite the w and z bosons why'd you have to turn the machine on to actually create them it's a question of focusing the energy so I I I don't I don't know why we're disagreeing on this point but but clearly there'll be a a message that doesn't answer the question what you're saying about what you're saying about 26 Dimensions well 26 and 10 at the same time well for two different string theories I mean no it's the you're talking about Sonic and you've got it's not consistent you think you the trouble is with string theory as I understand it now it's not really a proper Theory well they usually say eventually it's not a proper Theory it's a framework but that's a good way of wriggling at it yeah yeah well this is how they they avoid actually having to put the same constraints on themselves as they place on others and you know even in the situation um where you're talking about those Dimensions because it's lorenzian it's really two less than that so it's 24 and 8 and these are autonionic dimensions one of three octonianic three space generates all the large exceptionally groups it's an extremely interesting idea the fact that this doesn't work is is a different argument and what Brian is saying is true you know we can't feel neutrinos in this space thank God because they're tearing through all of us body and soul but the fact of the matter is that with sufficient care we can find the world that is hidden I think what what Roger's saying the way I interpret it correct because he's right here is how come everything that we can't see that you keep talking about you also have the right to place just outside of our umvelt and therefore uh 40 years later it's not really 30 it's 39 40 years almost after the the anomaly cancellation you've revved everybody up we're super excited and we're left with a practically North Korean level Narrative of the first string Revolution the second string then Juan found the the equivalence between gauge Theory and string theory and it's like we're waiting and the problem is everybody's revved up and people have lost interest in other basic theories and people are going to move off to Quantum computation and Ai and we're going to be left with digging out of this for 50 years why doesn't the strain Theory Community perhaps do something before that happens like hold a series of conferences called strings what went wrong were we listening who else is out there and bring other communities in so that we don't lose the fundamental physics Enterprise to Savannah hasenfelder and her adherence to continue watching this video click the link in the top left or in the description below or visit iai.tv for more debates and talks from the world's leading thinkers on today's biggest ideas

Channel: The Institute of Art and Ideas

Views: 288,292

Keywords: learning, education, debate, lecture, IAItv, institute of art and ideas, IAI, philosophy

Id: CNjckutR7BE

Length: 10min 29sec (629 seconds)

Published: Sun Jul 16 2023