Why Quantise Gravity?

0:00 I'll start with, it's actually a perfect time. I'm very hot. I'm not nervous. I'm just hot and I woke up at 10 o'clock. So please go ahead and take a look at all of this. It's excellent timing for me because excellent job by Jeremy and by David on explaining the basics, the foundations of current research. So I can now criticize these approaches. So here are the so-called approaches to point exactly. And I am skeptical about . Now, why is that? Because I believe that they undermine Einstein's theory of gravity rather severely. and they have a certain philosophy about generality, actually they disdain generality, and there is a fashion, if you are a physicist you know, there is sort of a fashion in physics department to think about that old man as an old man who had some good things going, but then he lost it. Now, the particle physics and so on is the great thing, and the spring theory is the paradigm, the new paradigm. Now, what is my problem with this? Well, these are canonical colonization, and we heard a lot about them. We heard a bit about spring theory, not much. Supergravity is just a low energy limit of spring theory. is the sort of particle limit of a stream theory. Stream theory, remember, is about strengths, extended objects, and supergravity is about particles which correspond to the stream theory when you take a lower limit. Supergravity extends supersymmetric quantum theory to general relativity, that means gravity. Not general relativity as such, but general relativity. Tell us a client theory, well known theories of the early last century, also can be seen as a special limit of social theory and so on. And there are further theories. I include many of these theories, except one. I don't include twisted theories. People have to enjoy the discussion, so I speak back on the further theories. But many other theories that you may not know are included. And the point is that all of these theories violate Einstein's principle equivalence.

2:30 And that is, to save the list, I find it very unpleasant, coming from fundamental theory, because Einstein's theory is based on some very deep principles. If there are reasons to doubt these principles, there should be some very good foundations of a new proposed theory to convince me that these are good reasons. So these violations, by the way, if you don't believe me, there is a reference you can check. These things are true, that these theories do violate the concept principle, despite the fact that canonical condemnation is based on the other. Departures from universal to a free fall, that means going back to Aristotle in the sense that now, now we go back there and say that heavier objects fall faster in these theories. Also, anisopropics being applied, which is a foundation of special relativity, preferred framework of reference, which is, sorry, it goes against the special relativity, preferred framework of reference goes against the very foundation of special relativity. So these are disturbing So the general attitude of the physics community, and primarily I'm a physicist so I come from that background, is that, so what, Einstein's theory is a macroscopic theory, it's a classical theory, so we don't really care, as long as we get it in some limiting sense. But as I said before, Einstein theory is based on the very deep principles. You cannot agree with them just like that. I don't have good reasons. Sure. Just a few seconds. Do you mind if I ask you? Yeah. General relativity itself already has a sort of a violation of the Einstein theory. That's not true. What about a body wouldn't drink its pen? Oh, no, but there is no violation as such. I mean, why is canonical quantization any worse than GR itself? Canonical quantization implies an asymptotic speed of light through the effect of the next goal situations. And this effective direct theory also implies different frame of practice. These are serious violations. But what about the, you're saying, canonical quantization, is it or is it not consistent with the problems for example? Canonical quantization is not consistent.

5:00 I mean, it's clear. It actually violates the multi-cultipulance principle because the universality of free-fall acceleration is not enough. Of course, it's a small violation. But as I said, there's already a small violation in GR. I don't agree. I know the issue of Spain. I know the fact that Spain has to be taken into account. There is no violation as such. I mean it's not that GR has been defuted by Spain that is not the case but that's a separate issue we can talk about so anyway I mean these things gave me reasons to doubt that the current approach may not be wrong but what to do I mean we have to do something for 85 years we are doing something and if this is what we come up with then we are in a very sorry state so to understand this of equivalence principle, we should try to understand. Unfortunately, I have a very long talk, so I'm going to go fast, but you can talk whenever you want. So let's try to understand what these equivalence principles or foundations of general relativity are. And in a naive fashion, you can basically say that there are two principles. One, both of them are principle of general relativity in a sense. Equivalence principle is applied relativity at a local level, whereas a special relativity is a relativization of time or equivalence of inertial frames of reference. General principle of relativity also implies principle equivalence, which we all know about, and that has to do with the equivalence of inertial as well as non-inertial observers. The point is that if you take just principle 2 of Einstein's theory, then you get special objectivity. Principle 1 only implies Newton-Kartan theory. Then if you want to understand the equivalence principle, then the good thing to do is try to see what happens in Newton-Kartan theory and see what happens to the equivalence principle, what implications it may have for theory. Now it turns out that this theory can be exact in contact. But first I have to explain what this theory means because it's just a non-relatistic limit of Feinstein's theory except that

7:30 it's a space-time theory. It's formulated in terms of tensorial objects and it is But there are some peculiar objects, the space-time matrix splits up into the time matrix and the space matrix. So in other words, the light form structure is flattened out, and we have two fixed objects. They are not dynamical, they don't care what matter does. Whereas in GR, Gminu cares very much what matter does. Compatibility conditions splits up also into conditions with orthogonality of these two matrix. Connection field can be also written in a similar fashion as GR, but now in terms of a rather familiar looking two-form. This is not electrophobic two-form. This has nothing to do with electrophobic. This has to do with certain derivational objects. And so you can write in a little bit like this. In GR, the theory, or the objects, the main objects of the theory are the connection of the matrix. Similarly, you can show that although the group of photomorphism in theory is larger, because there are at least more objects in the theory, in the end it is the photomorphism in theory. That means now we have two matrix, H and D, the space and time matrix, and the connection field, and then it transforms other photomorphism and the theory remains invariant or rather covariant. This equation looks quite similar, and the constellation laws also look similar but better than by hand. The point is that this theory is exactly quantized, but at the same time it fully respects, if you want to feel the invariant, and also respects universality of free-fall and Einstein's strong principle of equivalence. In a certain weaker sense, but it does. One convenient way to understand this theory is to look at the various theories in this picture, where it's C inverse, H bar, G are three fundamental constants, and the theories can be then put in various vertices and then you can see that Newton-Cartan theory is C equals to infinity limit of general relativity

10:00 and the quantized theory would be C equals to infinity limit of full quantum gravity or eventual quantum gravity. So that is where it sits. Now I'm going to throw at you some rather technical stuff without much explanation. But I just want to make a main point, what is the whole thing about. David and Jeremy both explained about action and so on. In Newton-Carson theory, this is the action. The whole thing is action. Look how many different terms are there. And the amusing thing is to compare it with Einstein's action. So the point is that it's a very messy theory. So it's not a beautiful theory. But it exists in tensorial form, and this relates to Harvey's point about any theory can be written in a tensorial form. So here's an example. So there it is. We don't need to know what detail looks like, but what is important is that this theory can be written in a Hamiltonian form They will explain what a Hamiltonian form means, and there are Hamiltonian equations of motion and just a detail So if you are interested in this paper, which I can give you reference to later Having written in Hamiltonian form and having known this messiness of the action, you can almost expect that there will be lots and lots of constraints. Tons and tons. And indeed there are many constraints. Remember in the Einstein case there are two major constraints. The momentum constraint and the Hamiltonian constraint. In this case there are 13. So you've got 1, 2, 8, 9, 10, 11, 12, we've been miscalculated by. The point is, that despite all this messiness, you can solve all these constraints exactly. You can get rid of them, which is not possible in GRS Jeremy and David Anderson. So, why do we want to get rid of them? Because we want to get classical face-face.

12:30 Unambiguously get classical face-face. And in this case, it is possible to get classical phase-space unambiguously, so there it is. We get a well-defined stucleptic structure and so on, and just believe me, it's there. So once we have a classical phase-space, non-ambiguous classical phase-space, no gauge degrees of freedom, no dynamical degrees of freedom, and no problems like GR. Now, let's recap this again. It's a very messy action, ugly theory, but beautiful face space, totally clean. Once you have such a face space, then the next step is to get completely unambiguous Hilbert space, which corresponds to that. But we know how to do that. Once you have a face space, we know how to do that, both in quantum field theory and in standard quantum mechanics. So you quantize it, there are some technical issues, so instead of the quantization, you use violation and so on, some fancy stuff, but you can do it. So in the end, you get unambiguous classical space space, unambiguous Gilbert's space, unambiguous theory, exactly so you can. But this theory respects equivalence. This theory is completely different. So that makes me think that why should I really care about all these approaches because this is such a serious violation of some of the fundamental principles of Einstein's theory. As I mentioned, The reason, the general attitude is that Einstein theory is a classical theory, a microscopic theory, and you should get it in some approximations. But we should not make any compromises with quantum theory, because the fundamental theory is a microscopic theory, and that's the way the world is. I don't agree with that. I don't agree with that at all, because it doesn't follow anything from what we know. Quantum theory, by the way, I'm not saying that quantum theory must be violated. But there is nothing in physics that we know in theory and in experiment that really requires that. So here is quantum theory, and here is the scale at which we are working. We are interested in quantum gravity, which is this scale right here, as Jared mentioned,

15:00 which is a very tiny scale, the scale at which quantum theory is valid and excellent theory in that domain is say somewhere between atom and quark and maybe a magnitude down here, a magnitude up here, I got it, no problem. So say 8 plus 2, 10 orders of magnitude. From there, at this level, 10 to the minus 16 centimeters, in order to apply quantum mechanics to quantum gravity levels, that means at Planck scale, you have to make extrapolation of 17 orders of magnitude. That is like, imagine Columbus went to Africa, America, and he found this beautiful pebble, very nice linear pebble. And he saw that, aha, this is very nice, beautiful, I understand this very well. And then he looked up. Now I understand exactly how the dynamics and the intricacies of the Milky Way works. that is the number of magnitudes which is involved between this level and the magnitude. 17 orders of magnitude is an enormous amount. But that's not an argument, it's just a heuristic theory. Something else, quantum theory is excellently verified experimentally, but so is GR. GR is also verified excellently. Now, validity of quantum mechanics is about 10 orders of magnitude, but validity of GR is from here all the way up to the size of the universe. So that's about 40 orders of magnitude. And there is not a single experimental effect that we know which disciplines with GR. It doesn't prove that that is the V2 theory, but it gives some credibility to GR. So two points. One is that the conception of GR is beautiful. It has deep philosophical structure. It's a monolithic theory. You can't take a piece of it. say let's just split it with 3 plus 1 or just make it flat or something. That's not GR. As soon as you do some damage to GR, it is not GR. It's a moral in the theory. And it is experimentally verified. So what have you learned so far? That I don't like the usual attitudes of quantum mechanics. But these are not reasons, these are just my ideological

17:30 opinions. Are there any real good reason for doubting the validity of quantum mechanics or not doubting the validity of general relativity? Well, of course we are, otherwise I wouldn't be talking here. And one well-known reason, as all of you know, is the black hole information lost. So I've just warmed up. And look, I'm not nervous. So here we are. Some of you know I don't know about black holes, but some of you may not, so I'll try to review it as much as I can. Black hole is what the neutron star collapses because the degeneracy pressure is not sufficient at a certain stage to hold the star up. It cools down and the gravity takes over and the star goes home and it collapses. Chandrasekhar discovered that while he was on the voyage from Madras to Cambridge. He was going to study with Eddington. And during the voyage in three months he worked this out that the star of 1.4 solar mass would collapse. There is no way out. This was a very radical result. Nobody believed him, including his supervisor, Eddington. He ridiculed him. He was 19 years old, so of course he had to shut up. He got Nobel Prize 40 years later, but that's another story. So anyway, so star collapses, and the causal structure goes bonkers, basically. I mean, all the light rays which were escaping to infinity, which is a normal causal structure we have to meet again, no longer escapes, even horizon forms, and the light cones are now inside this black hole, by the way this is time this way and space this way, what it means is that there is a mathematical surface which is in many ways physical because the light cannot or anything cannot escape from within that universe. So that is the effect of black hole. I have half a slide as well.

20:00 And there are some properties which I'm going to review, because some of them are needed. Our main unsold problem in general activity, I mean, glyphophysics is the so-called cognitive censorship hypothesis, but almost everyone believes that that is true. It just so happens that we haven't got the proof. And nowadays people believe that they need quantum verity to have the proof of this type of hypothesis. The reason it's believed to be true is because if it was not true then we couldn't do physics. I mean the whole laws of physics will break down, singularity is a dreadful thing. So it must have been protected by the mentorizer. One other important result is the no-have theorem. That means that any arbitrary black hole, when it collapses, you can classify or identify the star only by its gate charges. Because these gate charges are protected by the coupling with the gate sheets. This is what happens. You have many different magnetic moments, sorry, multiple moments of a star, any arbitrary star. say of a shape of a . Now when it collapses, it becomes a perfect sphere. And the only thing you can tell about it from outside is that its mass, sorry, the only way you can classify it is by its mass angular momentum and charge. In other words, all the other intricate multiple moments are lost. That's a remarkable thing. What kind of star which collapses, or or what kind of object it collapses, it could be galaxies, many planets, it becomes a perfect sphere. So Chandrasek called it the perfect microscopic object in the universe, justifiably so. So that's the NOAH Theorem. So stationary black holes are characterized by the mass, angular momentum, and the charge. So the point here is that a lot of information is lost. all the multiple moments that the star had, no longer available to an outside observer. It's called all sub-take, the information is lost. And there is the thermodynamic analogy, which I think I'm going to skip because time is running out. These are standard results. You can find it in any textbook or even in popular science books.

22:30 I shouldn't actually say that. In this analogy with thermodynamics, there was one major piece missing. And that was Hawking's radiation. Because without that, black hole had no temperature. That means you can't have an analogy with thermodynamics. Black hole, by definition, is black. Temperature is absolute zero. Hawking said that's not true. Temperature is not absolute zero. exactly the black body spectrum so here it is and once that piece was plugged in we have a perfect technology with some black hole, sort of the standard To understand, now what did we what did I say? Black holes suck up all the information, and all the information seems to have been lost. But as you may have noticed, I wrote down that this is epistemic loss. That means, although it's not a god-like entity can say, well, it's there, it's just that you can't tell whether it's there or not. So it's a lack of knowledge. Our lack of knowledge, we are unable to say whether information is there or not. It's not an ontological loss of information as such. So far, so good. That can't be a problem. However, there is a problem. But in order to appreciate that, I have to introduce some more technicalities, which some of you might be familiar with, as a Penrose diagram. Why is this technicality? Well, in order to understand black holes, you have to, and this is very characteristic of GR, any reasonable GR problem, if you want to understand, you have to understand what happens to infinity. That means what happens to an observer, which is a and that is part of the whole thing, package of GIA and in order to understand that Penrose, and actually Carter before Penrose worked on these diagrams now they are known as Penrose diagrams and the point is that you bring the infinity home you compactify the whole of spacetime, so now the infinities are right here, so this little diamond, I say a diamond because I have drawn only half of it, so there's a little piece missing.

25:00 The reason is tradition, you just use the other half of the triangle because that's enough to understand the causal structure. And the point is that it's the causal structure which is important in any of the general artistic or even special artistic processes, not the distances between things. Distances are not really relevant. What is really relevant is how these distances are causally connected with each other. And so these are causal diagrams. And one uses these diagrams to analyze the information loss and to understand that this is the law. Am I going to, just please stop me. That's a very, very good question. Is the learning background, is there any one I0? No, this is not an extended, this is an unextended space, you can have an extended, any space time can be extended, if it is extended, and then you have all sorts of equals. But why not? Just stick to the simplest possible. So now, let me slow down because this is important. So what's happening? So the star is collapsing. So now I'm going to describe the star in terms of this causal diagram and this shaded region is a star which is collapsing. So time goes this way, and space, now you see, is peculiar. R equal to zero is actually this whole distance. So distances are not important. All the relations are important. So zero point, the origin is stretched out. Strangely. And the past null-infinity is here, the future null-infinity is here. This is past time-like infinity, this is future time-like infinity is not there, because there is a singularity, this is space-like infinity. And the foliation of this space-time is just a standard, except that each foliation is now locked up in the space-like infinity. So now you look at this foliation, a typical slice, the sigma, and half of the clock, part of the sigma, is in the event horizon, event horizon is not just a line, a red line, and part of it is inside, however, this is the same description as that picture of multiple moments that I showed, it's an epistemic loss, it is in the event horizon, but a godlike entity can tell whether it's there or not, there might be philosophical questions here which I'm not interested in, you see what I'm

27:30 trying to say. It's not an ontological log, it's not a non-unitary dynamics, that's the point. Right? It's a unitary dynamics you can describe between unitary dynamics. Okay, so far so good. But, Hawking said that black holes radiate. Black holes are not black. And if they radiate, then they evaporate. So that means, at some stage, they disappear. But the information is locked up inside the black hole. If they're going to disappear, then they're going to take the information And then we have a problem. Now we are facing the problem. Now the information is really genuinely lost, or so we think. So to understand that, the same sort of diagram, but now this part here, this little portion has reappeared. What is that? Well, that's the Minkowski space-time creeping in. Because if a black hole evaporates, the part of which was actually a black hole is no longer a black hole but Minkowski space. So that thing is like creeping in, just backwards. And then when the whole black hole is going to evaporate, we're going to get the triangle, just like Minkowski. And this is like intermediate state in which black hole is half evaporated and half not. So now we are in trouble because what happens is that here is this observer and the space-time is foliated this way. This one you can say fair enough, it is inside the event horizon but it's an epistemically lost information. you have this one here which is hitting the singularity and singularity is somewhere where we have no clue what's going on but why choose that foliation? you can always choose a convenient foliation in which you foliate the space-time in such a way that you do not really hit the singularity just go like this right? and that's fine, so then you are fine however, you can't

30:00 do that here This part is evaporating. The bottom line is that this observer and these two observers are not unilaterally related. And this is not something, just a picture, you can actually do the calculation and this is the calculation and result before that Hogey showed. that the black hole actually does destroy information. Any objections? immediate reactions? So that is a very obvious one. There are no objections. Oh yeah, it's a standard. Do you know? Aronov says that there are remnants. It doesn't say that calculation is semi-classical But why is there a random? The point is that this is a semi-classical approximation. You shouldn't just dismiss that. This is an excellent semi-classical approximation. Hang on, hang on. I'll come to it. Human-less black hole will have a classical field, and the quantum field outside the black hole will be quantum mechanical. So, some classical theory is excellently applied here. However, objection is well taken, because there could be remnant. Now, remnant hypothesis nobody believes except for SR-Roman. And the reason for that is that remnant hypothesis is not CPD invariant. And also the fact that we haven't found remnants. If there were remnants, you could have a density of remnants which could have been detected by cosmolytics. So that hypothesis is no longer which we have anywhere except R. Another hypothesis similar is that this is not necessarily a remnant but at the last stage there is a big explosion and the information comes out of that radiation. that hypothesis is no longer is believed because to have that kind of explosion requires energy there is just not enough energy in a mild-scale nugget of that kind there is only one possibility now and that is entertained by most people as in the only open possibility for saving the information so the people who are die-hard believers in quantum mechanics who want to save information They say, ah-ha, but the outgoing radiation, after all, black hole is evaporating, so outgoing radiation must contain some correlations, subtle correlations between the different modes of outgoing radiation, and that must contain some information, and that information then is retrieved, so that's the outcome.

32:30 It's not enough. You can't just say that this is the case, because that would be a statement of faith. You have to demonstrate that that is the case. And of course, people have been trying very hard and claim to have demonstrated. So let's look at that. I'm going to describe two possible such calculations, which try to show that this outgoing radiation, which might have correlation between various modes of outgoing radiation, can be exactly shown to be the hoping entropy. So if you get that result, then you have solved the problem. But then the information is just an epistemic information loss, and we are all free. So that's the idea. So, first, such calculations. And this will lead us back to some discussion that we had previously, about canonical contabilization. There is really no need to understand all the technical details, but here it is, if you have any questions. What they do is, and again, as I said before, in the discussion, that Astecar is very honest about it. He says very clearly that we're going to do an effective calculation and see what it was about. So they start out with a large black hole and think of it as an ideal guess of one of our three German kids. Don't ask for that. Just believe their formalism and take that for granted. and then can we show that there is such a correlation and can we show that the entropy comes out as Hawking predicted we have to equate the entropy with Hawking's prediction because we know that that's an excellent approximation so the result must be very good, very accurately true and what they do is that when they calculate this do you want me to explain all this? later in the discussion. So the point, the major point at which I say, aha, I don't believe

35:00 you anymore, is here. The problem is that in Astakar variables there is a complex object which is not just part of this calculation but part of the whole program of the root quantization in the Astakar program and that is a complex object of this form. It's a connection field which has a real part which is connected to 3D spin connection and another part which extrinsic curvature of the foliation that you're working on, the 3 geometry you're working on. Now... Can I just, sorry, can I just say, is this in the connection population, or the rule of the foliation? Oh, sorry? Is this in the connection population? I'm going to ask you to the connection. Yeah. Can't be like a solution. So I should say . The trick, so the variable is a trace of the formula with all the issues connected. So in that same formalism these people are working. This is Ashdakar and John Bias and I think there is Raveli as well. I can give you the reference. so the problem is this when they arrive at a certain stage they realize that there is no mathematics which exists which allow them to use this allow them to the analytical continuation of this thing sorry I shouldn't be using that word but anyway there is a mathematical obstruction of the soul which I have to run and they don't know what to do mathematical technique available to them to do anything about it so what they do is that they fudge this factor so it's they replace i with a real number gamma now this is if you talk to somebody like woodhouse nicholas who are experts in quantum quantization and geometric quantization this is nonsense you can't do this this is just silly but let them do it after all these guys are do it to see what happens so so they do that fudge and of course that fudge now has a name it's called Barbaro but it's calling Ritzi parameter but it should be called Barbaro-Nitzi parameter and if that factor of course shows up in all the operators all the observers that they construct and indeed it also shows up

37:30 in a peculiar way in the entropy calculation that we can carry out. And also, it turns out, I've written it in a form, that if that factor is equal to gamma 0, which is times the log of 2 divided by 5 squared over 3, then of course this is 1, and then you get exact result. But why? It's completely arbitrary, there's no physical or mathematical reason for this to be the case, they do not understand it, and in fact there is worse. The worst thing is that the theories they get, these are like the super selection sector, they get literally any proven theories. So what is the point? Since I had five minutes, I'll tell you a story. This is what my supervisor, Neshimoni, once told me about his own supervisor, Wibna. Some speaker was Wigner was sitting in the front bench half asleep, and the speaker was saying that in my theory with this parameter I can accommodate all these physics and I can do this and I can do that. One more parameter and I can do this and that. And Wigner woke up. One more free parameter and I can treat an elephant in your theory. So that's the point. Free three parameters not appear. So there you go. Okay, so string theories are not impressed by this. That's canonical, guys. What about us? We've done something better. And in fact, it was the string theory guys who did this checklist first. There were big articles in the Scientific American, big hype everywhere. The postdocs got jobs. They got grant money So, here's what they did. What they did was, again, I'm not going to be able to explain this until discussion, but in the string theory, or the modern parlance, the M field and so on, there are various objects, there are strings, extended objects, and there are membranes of various dimensions, the D-branes are the membranes of D dimensions, and strings are, they are basically defined like this in fact. is where the open screen can end. That's quite the biggest definition of the world.

40:00 So, they used these as a guess. Again, the value of the guess, just like Plastica did. And they did do their calculations, and what they consider is a specific kind of line-fold, an extremal line-fold. And then they show that the BPS stage, which BPS is Bogomolny, Prashad, and that state also satisfies this sort of inequality, and when it is saturated it's called external, then it's called external because of the PPS state, so charge for the mass. Remember that black hole can be characterized by only three things, angular momentum charge the mass. So here it's non-speed of black holes, they've just charged the mass. And when they do their tricks, they are able to produce Hawking's result exactly. This is the spring theory. So they get very excited. This is it. We have cracked the nut. We have solved the information loss further. But fortunately they have not. And here are the objections. So these are just a sample of objections. Big objections are not due to me. There is literature out there, there are very smart people that come up with objections of various sorts. As I mentioned, the name is Ted Jacobson, Hawking, Penrose also has objections, but he never acts at that time. The point is that extreme and near-extremal black holes are astrophysically irrelevant. What they mean, charge equal to mass, charge is saturated by mass. Now in any realistic black hole, charge is instantaneously neutralized by the environment. realistic. Also, the charge is zero and mass is also zero. So furthermore, there is no event horizon in flat space calculation. So these are actually just mathematical objects which have no physical relevance whatsoever. So it doesn't say anything about the real problem. The whole approach that I have made a criticism of is that these approaches are like looking for the keys where the light is, but one should face up and look in the dark

42:30 where the problem is, you see? So there are some calculations, no success there for various reasons which I can go into the video. But for me the main objection is that the flash is obviously fundamentally different from the real, church-based, general relativity called structure. If you sufficiently dilute the causal structure of space-time, if you sufficiently damage the general relativity, then of course you can preserve unitarities. But the problem is to face up the point where these two things really incorporate general relativity principles and continents. That is the main point. There is a further I think I'm going to skip various transfers now, but there is a final point that I have to make. Let me just throw at you, and then we can come back to you. There is a holographic principle I can put to that later. It's just nonsense. There is a conjecture by Penrose because of all this. He talks about Penrose is a minority, believing that information is truly lost. and he's got a conjecture which shows that how the information loss impactful is tied up with reduction of wave function. So that's another talk. So here, so then we can talk about the measurement problem and so on. That's another reason why one could think about it. So let's go back. What have I said? I see no problem in quantizing Newton-Cartan which respects different morphism invariants, which respects equivalence. I see serious problem in extrapolation I see a serious problem with information loss problems, because all the attempts they have come up with to save the information has not satisfied at least a minority of people like me, and even Hong Kong, on odd days. so there are various problems but there is one

45:00 final problem all the things that I've said so far people may agree or disagree or argue or whatever one thing you cannot argue is this final problem this is the famous or infamous cosmological constant The issue is this, you can't argue in numbers. The prediction of quantum, I can explain this in discussion if you want, but some people would know what the issue is. The cosmological constant which is predicted by Comitrill theory, which is just the vacuum and the minensity, and what has been observed, which now people claim is non-zero, it doesn't matter. The ratio is still 10 to the power of 123. Now, if you are applying for grant money from taxpayers, you better not show this to them. I should mention that there are many suggestions, many proposals as usual about any problem in physics. There are always proposals and arguments and so on, but this is a serious problem. It's a fatal problem. I don't need to show disrespect for quantum mechanics. That is not my intention. Quantum mechanics is a fantastic theory, but so was Newtonian theory. So we have put that theory in perspective. What is the issue? Where should we go? Which direction should we take? And I suggest, not the first time, a lot of people might have said this before, that this is the direction we should go in, quantum mechanics. We should look differently. Quantum theory It doesn't have to be reduction or reduction, it doesn't have to be anything but an effective such process. An effective singularity, an effective classical theory, should emerge from dimensional quantum gravity in the appropriate sense and do not disdain one in your other or other in the world of the first. Both of these theories are fantastic, they are served as well, but it's time to put them in perspective. Now, the first person to ever think about quantum reality was our master and godfather himself. After 1915, after finishing his GR, in one year he was thinking about 20 years ago. And so we have 85 years since in that time. A lot of work, a lot of smart people. Just to mention Direc, Einstein, Feynman, plenty of others.

47:30 and his vision, Einstein's vision, even today, is intact. So this is his program, and I think this is the correct program. So what does it say? Okay, quantum mechanics represents a major importance and that is a really limiting case, which remains to be seen of a theory of significance for this hour. One should not try to find a new theory by beginning with quantum mechanics and trying to refine it or reinterpret it. No hidden variables are out. That's not what he's saying. Instead, and this was Einstein's main point, one should start all over again. It's a hard time that you do that. As in fact, I endeavour to obtain quantum theory as a bifur, general elliptic theory, which are hard generalization. So I'll give him the final word. I have Jeremy first. Well, there's many things to ask about, but I guess my main, I'd like to think, perhaps as easy as a discussion to ask, is the question of general structure about your third quarter, which was your discussion of non-unitarity and the statistical mechanical calculation of a black hole entropy. Now, the broad question is that there seemed to me to be three different things to discuss, and I didn't get in your presentation what you saw as the connection. So the one first thing is explaining the radiation as carrying away the information in correlations between the different modes. Another thing is the final state of the evaporating backbone, the end state. And those two things are obviously connected with non-unitarity, but they're a little bit different.

50:00 And the third thing, which you spent most of the time talking about, in terms of detail on the slides, was programs trying to actually calculate the black hole entropy from a statistical mechanical perspective. Now, you presented those details as if they were contributing to how the radiation could carry the information away. But you didn't say anything about how even if you successfully got those numbers, it would relate to the radiation carrying the information away. And even if you satisfied us on that spot, there'd still be a worry about my second truck, a leg of the stool. I mean, the issue of the end state would remain apparently something yet to be discussed. What do you mean by end state? Well, these are not, as I mentioned to Lev, remnant hypothesis is not generally, except for Rono is not generally educated by the people who are on these days of modern gravity the main hypothesis and I'm coming to your conclusion the main hypothesis that people strictly can restore information is this correlation between various modes so I do not understand what people understand Well, as I understand, if the mass goes down, the temperature goes up, and you get into a quantum gravity regime at the end state, about which something needs to be said, even if you're quite happy that for the un-evaporated black hole, you have a kind of statistical mechanical understanding of A, it's entropy, and B, it's radio. Okay, that's it. So, in the initial technique, whatever the initial technique is, in that case, . Now we come down to the, say, kind of a . scale nugget, not a remnant, but a remnant has a different concept. Once you have understood that unitarity is preserved, even in the bigger world, it's

52:30 understood that, of course, unitarity will remain preserved at the part scale. That is the whole point, because as you cover closer and closer to part scale, the semi-classical But if you just deal with the problem at the semi-classical level itself, by showing this calculation to be completely ordinary, then there is no problem at the end. Now, another problem may have to do with my skipping of one slide. So here is a standard, I mean this is just elementary, this is an undergraduate, and so what the point is that is the black hole, which is A over H bar, and as a specific measure, or in Tupit's job, a coarse grade, instead of a coarse grade, there are some inaccessible states inside the black hole, The entropy, normally, in a normal physics, we get entropy because the states are not entirely accessible to us, so we coarse-train it and we get, in other words, we partial trace it. And the result is just a mixture, but it is not a real mixture, it's just an improper mixture. Or is it interesting? I mean, the Hawking scheme, and again, the greatest scheme that I skipped, and also anybody who understands, I shouldn't use that part, but appreciates general activity, knows that energy, entropy, these are not localizable generalities. So in that sense, entropy cannot be due to coarse grain. As Hawking puts it, it is due to obstruction of collagation. As a result, it is a measure of obstruction of collagation of certain phase time. So if there is an obstruction, unitarity is lost. And the result is the entropy. So that's what the intrinsic gravitation activity means. This is the two sides of the point. So if you count the inaccessible steps, then you have shown that it is not intrinsic, it is just a course-credit. So that's the problem of this capitalization. Is that a question or a problem?

55:00 Well, I think my question was the same, but I'm not sure that I've understood the answer. Which is, I mean, when you have the two In the first case you said there was no problem because you could just see the information loss as epistemic loss. I thought that then the string theory and the canonical quantum gravity calculations are telling you what you don't know about. These are the states that you're summing over. That's true. Yeah, but then surely they're doing that doesn't help when you've got a diagram that doesn't work like that, but has this... No, no, I mean it has. I think I understand a few of the problems. This is a side-class of a diagram. So space-time here, one is this abstract, and then the real back-home. There is a quantum field outside of the electromagnetic field. Back in front of everything. 0.9 degrees. this part of that whole picture is this particle. But that evaporation is not included in this picture. So the radiation is coming out. It is nowhere to be seen in this vector. What I think is that let's calculate correlations in those that relations are out-of-the-relations, not this. So this is not a complete diagram. This is where I... Sorry, David. and then some of the stuff about black hole radiation the first quick thing how reliable is that diagram I'm sitting at a substantial distance from a black hole ok it's radiating the aceton definition of energy, conservation etc at some finite point in my personal time it won't be there anymore but in terms of the details of the conformed geometry inside how safely can we see what looks like that I would say, as long as you understand this is semi-classical, that means the only thing which is not included in this diagram is the quarterback, the 0.0.0.

57:30 But what about the singularity? Singularity is completely, but singularity nobody understands. I'm not sure, but if I'm believing in the string theory or chronological theory or whatever, then I get close enough to the singularity and I believe in the space of the curve, and I've chosen all scales, so at some point my quantum gravity will be completely in, and I can't trust the space of the theory that close to the singularity. So this is where the calculations, this is one of the motivations of the true theory of quantum gravity, which happens to be string theory, so people say, will sphere out of singularity, And therefore, the complete process, the smeared out singularity, complete understanding of true quantum variable gravity, will be unitered. That's one conceptual point. But the physicists have to calculate, given that hypothesis, have to calculate and show that in physics calculation you don't really need to know the exact theory. You can do calculations. Physics is an art of approximation. So you choose a good one. If black hole is too big for your calculation, choose a small one. If black hole is too small, yeah. Choose a particular, because this is a problem of conception. Conception problem. I take that point, but their claim is going to be that unitarity is going to come out of theory. And your objective to that, not unreasonable, is, well, look, a priori, we've got information loss. But it seems it's historic to say to them, you've got to give me a full model of what's going on. No, that's not required. The argument that I'm putting forward, or actually the other people who I support are putting forward, is that you've got to take into account the structure, the causal structure, which is proposed by general relativity, which is excellently valid at the scale, at whatever scale it is valid at. So you choose a large enough black hole, and you know the fossil structure is governed by general relativity. Then you must pay attention. You can't say that, oh, let's just ignore topology. Let's just look at flat space, and let the human horizon disappear. You can't do that.

1:00:00 No. Okay, so, just to finish that thing, do you, are you intended to be an argument against any unitary description of this or specifically against the picture that comes out of the Ashtaka because it seems to me generically, I mean if we really take black hole as hot things seriously, we're perfectly happy with the idea that I take a quantum system in a high energy state, I damp it a bit, it entangles the environment a whole mixed mess but eventually the system decays down state, the pure state environment is a hideous, complicated, non-local but pure state. So we have a general picture of what's going on here. And it doesn't seem to me that you're presenting a knockdown article that says that a story like that can't happen here. What I think you are saying validly is that neither Ashdakar nor Whitton has come up here. Do the truth now. There is an excellent paper which doesn't include these two calculations, But all the previous, which now I think are outdated arguments, which are included in Armand, Gordon, Van der Vaughan, and Laura something, there's a paper, so, well, that's just a philosophy, I'm just citing philosophy, but in physics literature there are tons of papers which show all the possible arguments to save the information, none of these arguments seem to work. And I cannot produce a logical argument to tell you that you're entirely broken. Physics doesn't go that way. When you're on the frontier, you go with your gut feeling of what is right. What I'm trying to present is that there are enough circumstantial evidence to convict Barry George for murder. I'm grabbed by this issue of entropy, you know, what's happening with the information. I'm not sure if I can articulate this, because I only ever have the most tenuous grip on the Penrose diagram for the best of times. But what puzzles me is, I suppose it's an issue of how far you can push the analogy between ideal gas-type models of a black hole evaporating, and similar sorts of models in classical statistical mechanics.

1:02:30 So it strikes me that you talked about entropy loss as being tied to loss of degrees of foveation. And that seems to me a very similar story to the one you tell about, say, entropy loss on crystallisation. It's a loss of degrees of translation. I didn't get the last part. Entropy loss in, say, a classical statistical mechanics system, like what happens when you go from an ion gas to a crystalline, degrees of translational freedom. If you were then to describe the phase transition going the other way, and say what happens to the information you like stored in the crystal, the equations you would use to model it typically put some sort of Brownian component into the equation. So if you like, the randomness is put in by hand. Now it strikes me we're making this big thing about an ontological question of what's happening to the information. I'm just wondering whether there's a parallel going on in the mathematical modelling of say evaporation of a black hole. And actually what we're doing is mistaking a piece of the mathematical process where we put the brain in motion in by hand to something deep at The way I understand your question, or comment, is the criticism of these two people, strength theories and quantum theory. It's not my criticism of what I'm saying. What I mean by that is that these people have assumed that in order to save equations, they have to assume some sort of dilute guess from the equation. Now, the dilute gas in the case of canonical quantum theory is the quanta of three geometries. And in the case of string theory is the dilute gas of strings, which are of course tiny, long-scale strings, and degrades, so time planes are very sort of, or whatever object of that theory is. That's another point I should mention. Now the point is that anybody who is appreciative of general relativity immediately object to that kind of problem, that kind of understanding of this problem. Because you cannot localize entropy as little nuggets on the surface of event horizon. It's a global concept in general. many concepts are totally global concepts

1:05:00 and an observer doesn't see any event horizon an observer is falling in the event horizon doesn't see anything doesn't even know that he's falling in the event horizon just falls in an observer at infinity will notice aha, don't go in so it's a global concept so the PGR people immediately object to the very notion of what these guys are doing is wrong and that was one of the objections which I probably might be past. So what is that thing? Right, so the issue is one of whether the concept is well-defined in the first place. I certainly think that it's not that. The whole program on calculations, I'm presenting it to show that what people are doing and despite the fact that I accept their ideology for the sake of argument, I find a problem with their final result and calculations and so on. There's a little bit of a compatibility problem between your main island here and your almost fairway comment about the cosmological constant towards the end of the choice. It does seem to be an interesting point. I'm quite sure how quantum mechanics, it may not survive but I would like to make it easier to get it through. It's not like I'm saying quantum fields that have been missing, it goes up to the lake. That's a particular instantiation of quantum mechanics and bound towards objectual notions like background field and so forth, and I don't need to feel that strongly committed to it, and if you like curved space-time picture has problems, particularly in setting up that sort of semi-classical picture, and some of the problems are really neutrally bound out of that whole cosmological concept picture, so if I take the cosmological concept projection seriously, can't I just say well there's something terribly wrong with a semi-classical quantum gravity, and therefore the whole I mean, that is the argument of string theories, but cosmological constant is not a semi-classical theory, it's a constant. So in any theory, it has to come up as a number. And this is a constant which is calculated on totally completely quantum mechanical theory, quantum So when they calculate the 10, sorry, I'm not in order now. Can I just finish? Yeah, I've got a puzzle about this too. I'll get in the queue.

1:07:30 Okay, sure. So, the point is that that has been calculated and there is no reason for believing that that calculation is wrong. It's based on the theory, it's about that. Let me emphasize again. I might have given the impression that I dislike quantum mechanics. That is not the case. I mean quantum mechanics is an excellent theory in its own domain. And its calculation has to be respected. That is something profoundly wrong when you use calculations based on quantum field theory and try to... Cosmological constant is probably less. It's not a problem if you ignore gravity. Because only relative vacuum fluctuations, energy to vacuum fluctuations can be measured. And cosmological constant energy is an absolute energy. But in GR there's this little lambda there. But you said there's no reason to down that calculation. I mean, surely the screening of the calculation is that it's empirically wrong by 120 or in magnitude. And if we then say, OK, there's something terribly wrong here, we acknowledge that problem, which is a problem in the whole seroclassical structure. Now, if we hold that problem as a result, surely that invalidates the whole Hawking radiation. If we treat the constant problem serious, then I don't see how we can treat the Hawking radiation issue serious. Why is that? I don't see that. Well, because the whole Hawking-Archew thing relies upon a semi-classical theory of gravity, which we've just shown to have screening pathology. Which I've shown? Which we've shown from the cosmological constant problem, to have an appalling problem in it. There's something... No, no, cosmological... Ignore gravity... Sorry. Ignore Einstein's theory of gravity. cosmology as a thriving observational field in physics, which is based on general equity but largely on Newtonian mechanics, and lots of observations, about 90% of it is in Newtonian. So we have no reason to doubt the observations that cosmologists make. Now, cosmologists have made this observation, they have not considered, well they are influenced by the cosmological constant and so on,

1:10:00 But it's not dependent on general activity. It's only dependent on quantum field theoretical calculations and what they see in the universe. You go and check the density of the lecture. They find nothing, almost nothing. Yeah, but Joy, this is exactly my point. Because they find nothing, that's such a bit terribly wrong with curves based on quantum field. No, that's... Because it's wrong by 120 degrees magnitude. Curve? think to understand Here's the problem with this the calculated vacuum and as you said is 120 euros magnitude larger than the actual observed therefore whatever theory it was that gave us the damn fool 120 euros magnitude too large is a theory that we shouldn't treat that seriously if we don't treat that seriously then how can we trust it in the Hawking radiation problem Oh I'm beginning to understand because Hawking radiation has two parts. One has to do with the classical space-time, and another has to do with the theory of quantum field theory, because that is what means the polarization of the vacuum. Now, to me, cosmological constant is a problem for what we built here. So now you're saying that if you doubt that, I see. So what you're saying is that then the Hawking polarization of the vacuum shouldn't happen even outside the black hole because the vacuum density energy... Or we don't trust it. No, no, no, no, no, no. That's presuming something. I'm not saying that the vacuum is not empty. We know it is not empty. So what these two problems imply is that there is a much more subtle theory, which gives you Cosmere effect on the one hand, and zero cosmological concern on the other. This is not something, you can't just give up the whole bunch of math, you have to do something very different. But if I'm head over heels in love of elementary quantum mechanics, can I not take the painful decision to throw curve-based quantum field theory to the wolves and say, that theory is flat and wrong, I deny it is wrong, I've got the, you know, there's no period of rotation. You could do that, but you can't. And in doing so, then I save, by paying that price, I then save quantum mechanics and just that. And then a slight, a motivation for doing that would be the fact that I'm already a bit embarrassed by this field, so I think because of the cosmological cost of being a...

1:12:30 Well, lots of people are doing that. Lots of people have that. As I said before, that one has to go by their gut feeling, what is the right way to be efficient. And the Institute of Physics has told us that many times, minorities turn out to be right. I'm not claiming that this time it will be the same, we don't know. However, I think that this is not standard unitarity and so on. This is not right. Now, what happened in the history of physics? The history of physics is full of epicycles of all sorts. So when you confront a problem, I'm going to work out some clever efforts like this. And physicists are gifted at this. Or you can actually say that, no, I'm going to do something different. I'm not going to accept Lorentz's idea of this change in velocity and so on. I'm going to be Einstein and I'm going to follow up with a completely radical idea. It could be wrong, and most Einstein's are proven wrong, but one of these Einstein's is proven right. You have to try it. I don't want to push more on this in a third person. I just want to understand what is your proposal. You say that GR is much more probable to be correct because it's listed on IR. But, you know, if I arrange, and in principle I cannot do all that, I can do this. I arrange a massive body in the proposition of being in two places. bodies, such big bodies that they can really measure the gravitational field if it's in one place. So what do you say will be a gravitational field when it's in a superposition? Are we going to become Penrothian now? Are we going in Penroth's direction? So just tell me that you have got Penroth that there is no such thing as too much as an superposition. I have seen the thing what he said. That doesn't necessarily mean that I believe every single word he said. such a resolution as when we suggest, then maybe. Well, at least in today's talk, that is not what I'm saying. This is why I asked you, you didn't say anything about it. What is your position? Your position is to say that there is no such thing as a superposition of two massive bodies in two different places?

1:15:00 That may not be. We don't know. Let me quote the godfather of particle physics, which I didn't quote. Let's see what he says. And remember, this is a die-hard believer in quantum mechanics, like you. He says this. it is it is not inconsistent with what we do know breakdowns of position in your sort of scheme that you just adjusted at long scale it's a long scale that you see it's not inconsistent with what we know I'm sure the reverse is also not inconsistent. I'm sorry. I'm sure the reverse is also not inconsistent. Yeah, I absolutely agree. I think... Let me just say one more thing. If I may. To me, I'm suggesting a very unorthodox position. I'm not alone, by the way. There are respectable people. Two big guys are with me. Abner Shimoni would be with me, I think, and Roger Chandler is obviously, you know, I can survive. Now, you're right, it would be consistent to maintain quantum mechanics all the way through, all the way to the Avaientian Fantasy Act, that's fine. But it would be fantastically, I would be flabbergasted that a petal that I discovered on the shore of America turns out to contain the information about the dynamics of the galaxy, it's flabbergasted, 70 words of magnitude. That's just me.

1:17:30 Why do people think it's a bad thing if the dynamics of black hole of aberration is non-unitory? Oh, this is the right word. Everything is linear and unitary, right? unless somebody will show me this also I think it's physics exactly whatever I said, in the end one has to show experimentally this is an experimental science this is just a philosophy or rather even an ideology so in the end there has to be an experiment which is absolutely this is what it's not wrong despite the fact that it is being discussed as well I guess I've got two questions. One is, following very much on what you were saying, is it true that in order to get Hawking radiation and that whole field underway you have to adopt the semi-classical picture in the sense you meant that G is set equals the expectation value of T. Is that the only way of analyzing Hawking radiation? No, no, I thought not, but it seemed to be part of David's question that it was. I was saying that to get the back of an evaporation, which requires some feedback from the field, that's really so classical. If you just leave that out, you'll get a thermal walking radiation, I think. You'll get a thermal walking radiation unless you have a feedback from field to ground. If I have a feeling that has an accelerating charge just as background, then it will carry on radiating forever. Right, so the end-state issue and the eventual radiation, the non-unitarity, all becomes only an issue on present understanding if you put in a feedback. That sounds too interesting. The bankruptcy problem is a serious problem in some classical theory. However, if a serious problem at the theoretical level, at the conceptual level, it is not necessarily a serious problem at the practical level. If you have a humongous black hole, 100 solar masses, clearly the gravitational field just outside the image horizon is pretty seriously classical.

1:20:00 So even there you have to be, and whatever quantum theory comes out to be, it would have to agree with Hawking calculation for that particular case. So, and therefore people take Hopin's calculation so seriously, in extreme theory. I think that Strominger, for example, has been quoted in writing that he doesn't say anything wrong with Hopin's calculation. It's just that we can't reproduce it, that's the problem. Okay, well my second question is in a way on the other side of that cosmological concept problem, because I wanted to ask whether, and this is why I was interrupting the previous discussion, I mean, do you get the 10 to the 123 only in flat space calculation, where you cut off at the Planck scale? Yes, I do. Because it was my impression, vaguely, that that does indeed come by saying very plausibly, well, space is nearly flat, space-time is nearly flat, So we should be able to, from the QFT perspective, to estimate the vacuum energy density by doing a flat space-time calculation and then you get this horrendous 10 to the 123. But there is a problem in principle there. Somebody could say gravity, despite its weakness, could have, so to speak, a conceptual sledgehammer, which just knocks out the validity of a Casimir effect, like flat space-time calculation of what Lambert predicted should be. Yes. Now, in that sense, I would agree. I think that's what's happening. Right. I mean, in a way, I think this half of my question is more on your side than on David's, because it's along the lines of all. Yeah, but I see it on my side, because I'm just saying, anyway, yeah. So it's not possible to develop lambda-predicted within the present formalism of QFT on curves based on, or is it? I don't know. See, here, this calculation, you don't need that. Again, these calculations and observations are physics. Here I think the conceptual problems are not that important as they are to the black hole

1:22:30 because the majority of the universe is flat. That is absolutely nothing except for this one. So, flat space calculations are perfectly valid. I mean, the universe is empty by and large. Unless there are dark matters hiding somewhere which we don't know about. But maybe there are dark matters. You can find a region of universe, which is pretty empty, so it is pretty black But there's a problem about copper, and that is this thing actually diverges That's another thing That's why you need the copper Yes, I mean, I'm not worried about that. I'm just thinking that the very fact of slight curvature might somehow undermine But in what region? If you have a non-slap composite, this breaks down, but it doesn't change the empirical factor. Because you have accumulated the empirical factor at the region that is completely, completely factors. Do you see one? I see steptis in the home of your face. Yes, I mean, anyway, let's start to be sure, David. Yeah, I'm just going to say very quick, there is a blatant algebra we can get around, there's probably one, this isn't really a cosmological concept, this is the back of the initiative. If I want to shove a bare cosmological concept that just happens to be So you can rephrase this inconsistency problem as a fine-tuning problem. Sure, sure. But a fine-tuning problem is even worse. I don't know, I was going to say, it's bad that there's a lot of things I've added, it's rather being eaten by a fine-tuning problem. We have a lot of very fine-tuned problems and some of the problem issues. If I had to give a talk on this another one hour or two hours, I could show all this possible solutions. I think that's a good session on the flag, that's your get out of jail emergency solution. What I was going to ask, I mean they didn't have mentioned interpretation of contrabandics all the following afternoon, but this is essentially following up on the left, and you're talking about how high contrabandics go, Now, it seems to me, the whole issue of microscopic supposition potentially gives a bootstrap

1:25:00 by which your own sort of principles, because you're very committed to maintaining the sort of guiding principles of GR, the light unit, the low unit, the issues of locality, causality and so forth. Now, it seems fantastically, as soon as we go after some microscopic supposition, it seems the whole history of the interpretation of quantum mechanics suggests it's fantastically to get rid of that and be left for max-dop determinacy without non-local collapse and that's it. I would be perfectly happy with any approach whatsoever, no matter how crazy, if they reproduce GR in an appropriate domain in a complete, even-depth fashion. The problem I have, and that is I think I try to emphasize that any of these other approaches are not reproducing space, they have not recovered collapse in the proper domain. say, sure, but the existence of quantum mechanics in my discovery domain and the non-locality of collapse suggests that one thing we better take seriously is the Everett multiversal One thing we mustn't take seriously is the average fantasy. What I want to say is that if you're turning around, you're saying that the quantum mechanisms say, well, theory will in some sense come up with some solution to radiation, and you're challenging them rightly to come up with how it's going to work, and I want to say, let's Turn that round. Unitarity of quantum mechanics all the way up gives you a rapprochement of locality and the quantum mechanics of the lower scale. And nothing else seems to you. You can suppose something else, but then again there's easier burden to find something, given the fairly lamentable failure to find any sort of collapse theory that's remotely consistent relative to this. I'm not promoting the collapse theory. What would you be proposing, and to some extent I'd say, the burden is proof that I've got the major actions? Anywhere a new theory emerges, the whole idea of a collapse, non-local collapse, a bizarre idea, disappears. Because the new theory gives you a completely new way of looking at the world.

1:27:30 So there is no reason to believe that that one. And though it's just committed to collapse, I know. But I'm not. I have a lot of sympathy with this collapse idea, but I'm not committed to collapse as such. So, a new theory we don't know, whether it will have collapse, whether it will be still non-local, who knows? Whether there will be any new theory which is not linear, you can't even generate the measurement problem. So there is no problem. In the end, I'm afraid my friend, it boils down to your fate against mine. Oh sure. Well, to be honest with you, I know you can get the advocate, I'm quite dissuade, but I think that's what I'm going to share, but I suppose one important thing to come to is that there has to be a consistence here. If we're going to say a new theory can just discard the whole structural measuring problem, then why can't we say, well, a new problem, a new theory can just discard the whole structure of the information loss paradox? I mean, if it doesn't talk about information or the interaction, then I don't see that problem. It was not an accident that I only chose one or one-and-a-half life paradox. Because that is something that I want to avoid, very much. Because, again, I have an opinion about it. But I just simply, it's no point to discuss it, you know, as I said, it's just people have their ideas and they're just, it's going on for 85, 90 years, it goes to the point. So let's concentrate on something which is, which is impressive, like, information loss, but more of the quantity, the cost, and then see whether we can get anything out of it. I think that's probably a good place to stop. I'd like to thank the speakers, again, Jeremy, David, and Joy, and we could all thank them. In a certain sense, there's just been a sort of translation of the Oxford group to Leeds, but I think we've benefited from this interaction.

1:30:00 I think certainly for me things are a lot clearer. I'm not going to propose this for discussion now because it's a nice sunny afternoon, evening, and a cool pint beckoning outside of the room. I would like to have a final thought, really. Joy's final of Einstein's vision obviously provokes the question, well, where do we go then? How do we move forward? It's an obvious sociological point. The reason we have the kinds of theories and the kinds of moves that have been made is that they use tools that people are familiar with. They use tools that classical physicists, that cosmologists and so forth are familiar with. What do we do if we abandon some of those tools? What do we do if we don't even follow Einstein's vision and try and see quantum mechanics as some sort of bi-product of general relativity, but adopt Joy's vision, which is in some way to be prepared to drop perhaps aspects of both. And like the two flashlights. And the question, the final question, do we think that any advance is going to merely be a matter of a physical hammering? What we should do is go away from there, drink our pipes, and wait for the physicists to come back and say, here are these guys, have your weight a bit. or do you think that this advance is somehow going to involve the kinds of conceptual analyses that we would like to think we do so that's also just a final thought I think Voss has played an essential part all people do their PhD in philosophy or physics are going to play Can I come and do this? First, since it's such a... I'm opening up a bigger problem than I think what brought quantum. So there, philosophers are much more needed than if you just have to follow quantum mechanics. Once the, as you pointed out, the groundwork is gone, where do we go? There's no excuse. We must go. So we shall. Finally. To do this. Thank you all for coming.

1:32:30 Thank you all for illuminating. Finally, those of you who are looking for expenses, there may be a lot of help. If you can give me, either now and next few days, the list of expenses, I'll sort that out here. Thank you all. Thank you. Thank you.