Quantum State Reduction as a Gravitational Effect

0:00 Welcome everybody to our seminar and needless to say it's a great pleasure and an honour to have amongst us today a man so greatly responsible for the renaissance of general relativity in the second half of the 20th century and indeed the man responsible for so much else. Professor Sir Roger Penrose will give us a talk on quantum state production as a real phenomenon? Real? I don't know. I think so. What was the production? Well, I'm also a philosopher, so I'm worried about it. Well, well, that'd be fine. So thank you for coming. Thank you for inviting me. I'm not sure whether I should just assume everybody knows about all problems. I think I'll say a little bit. Thank you. and that's what we call quantum level usually describing small systems like atoms and molecules and so on and so forth whereas we use a completely different description for large things classical physics I've used to have to see for that and view the standard energy emission but that's only half of quantum mechanics basically because we know that that Schrodinger equation by itself doesn't give us what we see, and we have to adopt, certainly in practice, another procedure known as collapse of the wave function and reduction of the state or something, which is what's involved in the measurement, and I use the letter R, stands for reduction of the quantum state, and mathematically we use a completely different description, we look for eigenstates of operators and so on and so forth, we don't use the

2:30 Schrodinger equation to describe what happens when, in practice, we might say, magnify a quantum event to the classical level, such as the Geigertand, which means a quick, which is a classical level thing, whereas the significant particle would be considered to be a quantum level object, and somewhere in between a part of entering a device and you hearing it is something else going on, which is described by this other procedure here. Now, people have endless different ways of coming to terms with this, and I have a slide here, which is supposed to accommodate at least many of the main viewpoints. The problem being, of course, is that if you take as many as you can try to, the quantum level is being all levels, because it seems to be inappropriate to draw a line somewhere. So if you think of the quantum level as being all levels, then somehow we've got to come to terms with both these aspects of seeming reality. That is to say the classical emergence of the classical world and somehow the quite different procedure that seems to be adopted whenever a mission is made. And on this other chapter here, I've listed various new points. So this was actually for a talk, I'll have a different one from this, but where I was trying to say something about the role of mentality, primarily to emphasize that my own position on this issue is different than most of the others that one hears about. But I was trying to make the point that as far as I can see, almost all the standard or even slightly non-standard interpretations of quantum mechanics bring in mentality at some level. So if you just take the Copenhagen views here, which is basically, well, there are two slightly different versions of it which I'm describing here, but the point of view is that the state vector, which I've indicated by psi in this direct bracket, is not considered to be a real description of the world. in the sense of reality

5:00 and the real and the sense of real are complex numbers. Of course, we don't have the confusion because we know it's a complex object to be said in a number of numbers. But the question is whether this is a real thing or does it simply exist? It might be better if I had an authority test and I would stand to keep this view. Or am I? Am I standing in the way or am I standing here? or I can do it this way next. Let's try it. The thing is that this is not considered, well, it's not considered to be real, the statement is not considered to be real in the sense of physically real, but it's basically somehow an ideal description that some experimenter might make. So it's something which has its existence in the mind of the experimenter or observer, and therefore that means it's a mental object in a certain sense. of reality. So they're already bringing in mentality, even at this level of interpretation of the state vector. So it represents the observer's state of knowledge, that's the way it sometimes is said. It's not physically real, but it's just sort of maximal knowledge that one might have on the system. And that when a measurement takes place, so this new maintains, this is not considered to be a puzzle, an inconsistency with what goes on here, because it's only a fundamental picture of what's going on which is suddenly changing from physical reality. So that's really saying a lot of this picture is in the mind. So the mind is brought in already there. I find that daunting because it seems to me, okay, there's lots of things you don't know about the mind, and I'm sure, according to my view, it has some view of quantum mechanics too, but I would rather push the problem further back because we know so little about it, and the rules that we apply in quantum mechanics, not such as the Schrodinger equation, but the rules involved in measurement, are described very, very precisely by mathematical formalism, and the probabilities that you work out are very, very precisely determined, and the support that quantum mechanics has, the very broad support that it has in many different kinds of experiments, owe as much to the accuracy of this procedure as they do to this procedure. So, to put the blame on some kind of mental description would be a bit dangerous, because why do we get such extraordinary precision when it's some kind of fuzzy thing

7:30 we don't probably understand? Well, that's just part of the Copenhagen view. Now, here you might take different views. the Copenhagen view just requires what one would call a classical measuring apparatus and is that classical measuring apparatus well it's just convenience that you have some large object that you treat classically for convenience well that seems to me is not really answering the question because how do you know when it's a large enough object to be treated conveniently as a classical thing is that fair or is it really when the observer or the experimenter comes along measuring apparatus and sees the point of points one way or another, then it's some kind of consciousness that comes in at that level. So two levels of which, one seems to certainly come in on the CPU, another level at which it might, I don't know how you look at it. But it seems to me, if you don't read it, then it's unclear what the measuring apparatus is. I mean, when is your thing that you're experimenting on and looking at when is it part of the measuring apparatus which is the case, why should you be treating the plastic? It seems to be cheap. Anyway, so that's what it seems to come in here. Environmental decoherence, well, the point of view here is that your state is only part of the system. of course you've got to worry about the contanglements of the environment the question is, well, you say you have no control over the many, many degrees of freedom in the environment and so therefore you say, well, you give up and say, well, we don't take them into account in this day if we do something else, we sum over the basic deconstructed density metrics I'll say a little bit more about this viewpoint later, but it does seem to me that even that puts off perhaps the problem of the observer, it really comes in sort of in various places. For example, when do you say that the information in the environment is irretrievable, and that really just depends on technology or on the observer's point of view or something, because you might have a better, somebody who had a more precise way of extracting information from the ground and putting it all back again, something like that, seems to be a matter of convenience. it's called FAPS, for all practical purposes, that's John Bell's acronym, and he chose to

10:00 make it seem rather ridiculous point of view, just because it sounds like an absurd word, but that's not the fair criticism. It does seem to depend on the observer's point of view, And in any case, I remember having a conversation with Zura, who was one of the big promoters or supporters of this view here, and at the end of our discussion, he was clearly taking refuge in the next point of view, which is many worlds. It seems that this is only a temporary place for all practical purposes that we like, but it's not really sufficient to view the viewpoint of philosophical standards with regard to what the world's like. It's certainly a logical place to be driven if you take the view that the quantum level is everything. And that unity of evolution is everything, and this describes reality in some sense. It really is. There is a world which is described correctly by unity of evolution. And then when it's driven to this point of view of the Australian's cat, which I want to do shortly, which you could, as one observer seeing a live cat, one seeing a dead cat, and so on, they coexist. this, and that somehow you have to make sense to the fact that you only see one or the other rather than there's a combination of dead and alive. So the question of what is a world depends on, excuse me, depends on the conscious perceiver. So if you're going to take the many worlds seriously, and I would agree with the many worlds people, that if you are insisting on evolutionary evolution at all levels, that's what you're dreaming. I don't believe that it's pushing the brain back on conscious perceiver again. The question is, what is a perceiver? Why is a perceiver somebody who can't see combinations of lives and just cats? They're telling you something about what conscious perceivers are like. You have to know what conscious perceivers are like in order to know how to make use of many worlds, in fact. But you are coming back onto this issue

12:30 of what a conscious perceiver is. And I've mentioned There's a viewpoint that you have to tell at least some stages are, which is that living beings, or perhaps conscious beings, somehow Jung's resolution doesn't apply and at a certain level the reduction state objectively happens. My own point of view that I'm not going to talk about this here is that what we need is something, a change in a real world pondering. So this point of view here is going to be an approximation. Now that we've got to look for some better theory. I should do all this on this. Approximation to a reduction. But the whole thing will be approximation in a new theory, in which something very close to the original description of the new theory is now, something very close to this, this will be very close, this will be a good approximation to whatever this new theory is. So this is my point of view, we certainly have to look for a new modification of my mechanics. It's an objective thing, it's something in the objective world which does not follow Australian Revolution's acting, but yet the question of mentality and consciousness is not removed from this, it's just put on the other side. The idea here is that the phenomenon of consciousness requires this objective phenomenon, OR I call it objective reduction of the state, it requires this missing physics, consciousness is some phenomenon, physical phenomenon, which takes advantage of what this is. So it means also that we're a long way from this, because we need to know that physics, or we can even start seriously addressing other aspects of how consciousness arises on this particular viewpoint. I put at the bottom the de Broglie-Bohm point of view, it seems to me that this may be one of, or the only one of these which is, in a certain sense, has an ontology which is a conscious, or some kind of an observer of some sort.

15:00 Nevertheless, if you read the works of David Bohm, you'll find that he's always talking about intelligence related to that. So, I'm not quite sure what his position has been on this particular question. Anyway, this is just to introduce my own point, if you really is to reject all these, to say that there is something objective taking place. I think I'd like to make a few comments about because it's certainly a point of view that often people think that that's really what's going on and why should we worry about all this philosophical stuff and it's really just because the environment is so complicated and that's why if you get reduction apparently it doesn't seem to me that's very close to It's a picture, not just a picture of the world. The problem, of course, is the cat. There's a version of the cat here. You can see the sirens here. Here we have a photon state coming along, a beam splitter. The photon state is split into these two parts. And this is the detector which powers some lethal device, some sort which kills the poor cat. And, of course, you have to consider that the two parts here coexist. The mean splitter, there's no one or the other at this stage. The state has to be a superposition on that side one. If you went in and had a cap here, you might have a tap of Mark Sender in the barata. Ordinary mirrors here and a mean splitter there. And then if these arms are all the same length, then every photon coming through here will be picked up like this. experiment, never this way. So that means that the photon necessarily fields out both roots. How do you know, how would it know to cast itself out this way and to reinforce this way? And so that means you can imagine these arm lengths were light years apart. So we know these photons are traveling for all this time, keeping I mean, it's a photon, it's one photon. One photon in a second position for all this time, keeping the wave relations actively So the cats are happening this way, how does the experiment know, how does the photon know, which you might want to put a cat in there instead of the two other mirrors, etc. And so you have to consider that they do coexist, and these things are in superposition, and because of the linearity of the Schrodinger equation, everything continuing from there also has to coexist in superposition,

17:30 and so the firing of the gun co-existency position and so therefore the cat is dead and alive at the same time. And that's the problem of the showing of the cat. In fact, the problem with showing of the cat is even more serious and dead and alive. It's something that I like to show because you know that the spin states, you can form every possible direction of spin out of, say, spin up or spin down using the complex numbers. You can read the complex numbers, you can read the complex numbers, that relates the geometry of space to the formulas in quantum mechanics. I always find that particularly attractive picture of quantum mechanics, but of course, since we can do that with a particle, why should we do it with a cat, too? So here we have live, cat, dead cat, so we have not just dead and alive, dead plus alive, dead minus alive, dead plus alive, dead minus alive, dead plus alive, dead plus alive, dead minus alive, dead plus any complex number of life and complex number of times dead. and all these things are in principle physically distinguishable you can do experiments which certainly you did many times it would distinguish people from alternatives that's of course not good but why should we how do we know something that seems to be a matter of principle here to put the blame on that practicality seems to be that's not the point Okay, let me say a little bit more about environmental coherence and so on. But before coming to that, I want to say something about EPR effects, because this is a very much more discussion. These are famous experiments now. The famous one of aspects, we have two photons now, sent lots of directions correlated. They were initially, I think in his experiments, in one state, and then you have these detectors here, the photon doesn't know in a sense which way this optical switch is going to be adjusted until the photon is in full flat, because the decision is not supposed to be made until these things are in full flat, and then depending upon which choice is made here, which choice is made here, you get correlations which cannot be explained by these two photons being separate individuals.

20:00 objects without any kind of connection, communication, or knowledge, anything of this sort, and these experiments were known for over 10 years now, I think, but nowadays experiments were just 12 meters apart, but these different detectors have now replaced by something like 10 kilometers, so one knows that quantum mechanics still works over very, very large distances. In fact, even more than that if we take these observations of star diameters using the Hamlet Brown twist method when they measure the diameters of stars using what is in effect of Bose-Einstein and the fact that so that photons are always because they satisfy Bose-Einstein statistics so if you have different photons they're always part of the same thing because there's a symmetry between the states and that fact is responsible for the fact that you can actually make these measurements of stars. There you have the size of the star, you have the photons coming from two edges of the same star, and because they are naturally entangled, so they're photons and objects, this fact is exhibited in the fact that these observations actually work, which is a great puzzle for people when they first suggest these experiments. Okay, so that's EPR. Now, what I want to do is to look at environmental decoherence as an example of EPR, I'm sure this is the way people often look at it, but then do it here. Here we have the sort of simplest EPR bone system where you have a spin zero state and it sits in two spin halves, So we have two particles of spin half going two places, so it's been zero. And this can be written as a combination of up here. This is here and this is there, over there. So I imagine that we're sitting over here. And some colleague over there is receiving the other article. Let's put the colleague on the moon or something like that, a good way off. And this thing could be said halfway between the moon or the space station or something like that. And my colleague is going to make a measurement on this Spinhardt particle.

22:30 The measurement might be up and up or down, say. In which case, and let's suppose the space station is closer to the moon than here. So if my colleague at Boreas is up or down, then whichever it comes out, I don't know which it is, because my colleague hasn't told me. But at least I know it's either up or down. And so I say, well, the state is either up or down. I don't know which. Well, either down or up. It's the other way around from my colleague's measurement. Either down or up. I don't know which. And so if I were to make a density matrix out of this, I would consider it as a probability mixture of up or down. Now, it might have been the case that my colleague in the last minute chose to measure right or left instead. In which case, if I knew that, I would say, oh, it's probably the mixture being right or left. Anything on what answer my colleague hadn't obtained. As far as my own policy is concerned, it doesn't make any difference. I mean, it's equal mixture of up or down. I get the same probabilities whatever direction I choose as I do with equal mixtures of right or left. And here you see right. I'm supposing that right is essentially down plus up, and left is down minus up, normalised with a skewer of two here. And I could do the same thing with left and right if I wanted to. So there's nothing wrong with that, that's just the way things work. It's puzzling if you worry about what reality is like, because you might say that if my colleague has already made this measurement, then the spin state I have is either up or down, I just don't happen to know which it is. There's nothing wrong with that unless my colleague happens to tell me which way he or she has made this measurement, in which case I don't have to use the pass state to worry about the entanglements and so on. If I have no information with my colleague, then I could use a density matrix. Equal mixture of up and down is just as good as equal mixture of Bob Ryan and Z, there's no difference. Although, on top of the logical, in that case, it's different. If you believe the stage is real, then you say an equal mixture of up and down is a different thing. An equal mixture of right and left is just I have no way of telling the difference by imagining it.

25:00 But let's see what this has to do with environmental decoherence. We'll put a cat in here. I'm doing a similar experiment here. And the usual way one looks at this is to say, well, the state is some entangled mixture like this, with a live cat entangled with some environment, and a dead cat entangled with some other environment. the most idea of what the environment is, so I sum over these states and I get the probability mixture of blind and dead, and that's more or less where the story tends to end. Of course, that equally well can be represented, as I did with the left and right case. The probability mixture up and down is no different from the probability mixture of right and left, so I could rewrite my state as a probability mixture of life plus dead and a probability mixture of life minus dead. It hasn't gotten anywhere, really, from the point of view of reality. See, it doesn't tell me that the cat is either alive or dead. Equally well, it tells us that the cat is either alive plus dead or alive minus dead. Or it could be alive plus I dead or alive minus I dead. It does tell me the energy, it doesn't actually dissolve anything, so I'm going to talk about other worlds. Here, of course, it has, which you should probably bring the environment in as well, but let's just consider the observer and the cat. So here you have a case with an observer seeing a live cat, and there's a mental state. Whether you can treat a mental state as part of the cats you might worry about, but I've dealt with that problem here by putting the expression on the person's face, which is a happy person perceiving a live cat, an unhappy person perceiving a dead cat. But of course you can rewrite this state perfectly well as this plus and minus business that I just did before. It doesn't really resolve anything unless you have a view of what I was saying at the beginning. The observer is a here person now, so it's a there person. That's more appropriate here. There's some difference, of course. The question is why do we sometimes single out these states where you just perceive live or dead,

27:30 as opposed to being in a mixed state of perception? But we don't know that, and we don't know what perceptions are like. In fact, we're going to base our physical theory on something we have very little idea about, particularly when one has such precision in the rules of quantum mechanics, that seems to me to be the dangerous idea of getting this very far. So, there's the problems I have with this world here. We need to have some preference to states, which are in some sense not these secret positions. we know more about mentality it seems to me we can't say much about that. Sometimes people object in this example that I've given you that this is a very special example in which the eigenvalues of the density may be for people. So rewriting these states in this way is not very simply, so people say oh well that's a very special case, because that's more arguments because if you've got to have a viewpoint which makes sense, it should make sense in this special case too. But just to emphasize a really serious point. The fact that the density matrix is diagonal, as equal eigenvalues, is not really a point. One way of illustrating that is to go to this very beautiful example of Lucy and Hardy here, where one has... Well, I've done first the black box here. You have two black boxes here, and I can tell you these are spin-half objects, or they could be protons with two different states of polarization if you like, but I think they're spin-half objects coming each way, just like in the E.P.R. bone situation I was just talking about. that you could make a measurement here, which is up or down, and then you fall in the right and left. Now, let's consider those two offenders, the two other angles, of course. Let's consider, in this situation, either up or down, or right or left. And you look at this particle and measure one or the other. This person over here looks at it, one or the other. And the rules, according to this particular... There's a question mark here about what the state is in the beginning. I'll tell you what the state is in the beginning. There's some particular state, splits in two, and these have each been half particles, and you make measurements either up, down, or right, back. And the way it works out is that sometimes, in fact, at twelfth time, if you choose up, down, up, down, at the two sides,

30:00 suppose I and my colleague both have to choose up and down, or let's say the measurement is down, up and down, up and up, whichever it is, sometimes we're both going to get down, about a twelfth of the time. So the system has to be prepared for at least a twelfth of the time, if we measure up and down, it gives me down and gives me down. But it also, on those occasions, must be prepared that if my colleague changes his or her mind to measure it left-right, if I get down, then my colleague must get right, never left. If I change my mind and measure it left, then my colleague and my colleague had the original down measurement, I never get left and down. So if my colleague gets down, I must get right. Now you see, if these particles are kind of separate independent objects, and they have to be prepared sometimes to give down-down, if we both choose down-down, the system doesn't know I might choose down and my colleague chooses left-right at the last minute, changing its mind to left-right, then under those circumstances, the system has to be prepared, if it's going then it's got to be prepared to give my colleague a right measurement. Likewise, it's got to be prepared to give me a right measurement if I choose, if I write that, if I choose it up, down, my colleague chooses it up, down. But it also prepares me to say the right, right. So we can see there's a contradiction here. If these are separate independent objects, we should never organize this. It's just not possible. It's only 12 times, so there is a little bit of probability coming in here. The only place where the probability comes in is in here. All the rest of it is just guess-don't mention this. So it's a contradiction to the contents of the boxes with independent objects acting without communication or foreknowledge, or what we call rectangular objects. But that's some kind of connection between the two. It's a mystery of consciousness. How do we do it? Well, here's how the example works.

32:30 I've chosen just a particular case of these examples. It's very easy as one to describe, where you just get up and down and left and right. The initial state is in one state, which can be written like this. That is, it's the sum of left and up at the Spani angle plus up at the Spani angle times left. So this needs to be here states and those are the there states. And the funny angle is the angle which is slope of 4 over 3. It's just a 3-4-5 triangle. And it's just a little bit of a calculation to show that the state here is orthogonal to each of these ones, which is the basis of the never statements. Orthogamous is that these never happen, you see. there's no statements. Whereas sometimes, down-down, that means it's not a problem, it's a down-down, and that's a calculation, you can just do a calculation. There's some nice geometrical ways to see why this is helping. So you could take this example rather than the one I had started with, which is the North Amelia-Boehm example. You work up a density matrix, you find it's by no means equal eigenvalues, it's a, well this doesn't tell you, just is, it's a, let's see, yeah, this is, if my colleague chooses to measure, let's see, if my colleague chooses to measure up, down, then I find this density matrix over here. You see, it's a probability mixture of two states which are not a problem to each other. My colleague does a perfectly ordinary measurement, which is, I think, maybe a lot of work about this. And I get this density matrix, which is a combination of two and a lot more states. Perfectly all right. If you work out the agribalues, you'll set the fact that they're not equal. And I can do it in my pictures here. Let's go back to the example.

35:00 I can write it as a combination combination of up-left, and down-up. So I guess in this case, it's me making a measure, isn't it? Well, this one's my colleague making a measure. If my colleague happens to measure up and down, see, then I get a probability mixture of down and up and right, and they're not a problem. Whereas my colleagues, I can barely have to be a problem, that's part of measurements, but the affordability of my colleagues' measurements don't mean that, in this example, that my states come to me as normal affordability. I don't think I'll go through all this, but it's just to show you that that business about equal iron value is a retainer. It's telling you that simply knowing the density matrix isn't telling you very much about what's real. This would be going back to the original case. It's been zero, it's been misrepent. The density matrix should be rewritten in the side of x. I don't want to spend any more time on that. It's really just part of the reason I don't really think the environmental new coherence point of view is, at a deep level, telling me. It may be useful in practice, but you realize you've lost all the information. The best you can do is form indexing metrics. In any case, it's only fact, because it's also technology-dependent. You might have a much superior technology which kept track of all the things and so on, and then we would need to know what the actual state was, not just the density matrix, which is a sort of all practical purposes object.

37:30 Another point I should make here is that sometimes people have a rather shifty ontology in these subjects with regard to density matrix. They might start off by saying that there's a probability mixture of states, and then you can go through some dynamics and then you construct the density matrix, and you see it's practically diagonal, and then you say, oh well now it's a probability mixture of states. the ontology shift is starting off by saying it's a probability mixture of a certain set of states, any form of density matrix, you change your mind and say the density matrix is describing reality and therefore you don't care how it's constructed and then you go back again and say well that density matrix is telling you it's a probability mixture of states but it's a different probability mixture from when you started with it. So there's some passive work going on in many interpretations here. So I should stop my negative comments here. I'm trying to be a bit more positive. The point of view I have is that you really have to look to places where general relativity and quantum mechanics start to impinge upon one another. The quantum mechanics seems to work extraordinarily well, there's no question about that, but the formalism of quantum mechanics is in a certain sense rather incompatible with the formalism of general relativity. Of course, there's a subject of quantum gravity, which people, well, there isn't such a subject really, but the real quantum gravity is. But the sort of thing people do is usually the first in the reading here, is this appropriate application of quantum field periodic procedures to understand general relativity or to some modification thereof because usually they don't mind changing general relativity, adding extra I don't like to change the procedures of quantum mechanics, whereas to me, it seems to me that we need something more easy-handy between generative quantum mechanics. they're both extraordinarily accurate theories in their own realm based on very logical principles and mathematical formulas and to support them, but when you start to look at places where both become important together why should we simply say, well, GRO's got to squeeze into a certain work of

40:00 quantum mechanics. It seems to me the quantum mechanics has its problems with the edge of the problem anyway. and so surely one should be looking for places where important changes might come in. I should say one of the reasons that I believe we do need a change in structure quantum mechanics comes from when we look at space-time singularity the grossly time asymmetrical nature, but let me not say much about that because that was really the subject of the talk I gave at the, a lot of it was the subject of the talk I gave at the physics department a couple of weeks ago What I want to consider is a situation where you have a cat, you see, is unnecessarily complicated because you have to worry about the cat's consciousness and the complication of the cat and all sorts of things which are probably irrelevant to the main issues. I'm considering a lump of material just sitting on a horizontal table, which is put into a position of being two places at the same time, which you should be able to do in quantum mechanics, as with the cat, in fact, let me just bring that slide up here, here we have a device, you can see which is, that's the same as the cat, it's moving this lump from one place to another, if the furland goes this way, if the furland goes this way, it leaves it alone, so according to linear, shortening of quantum mechanics, the state has to be in the linear superposition of those two places. The question I want to ask is whether that superposition is a stationary state. You see, in your marine formalism, if you had a superposition like this, then... I've used the word killing data, so let me explain what that's all about. I'm going to bring general relativity into this, so we don't have to worry about gravitation.

42:30 and if we're talking about stationary states well, you imagine your background space-time is stationary and if that, let's consider just one lump for the moment, so the lump is in one position for the moment then there will be some gravitational field due to the background and due to the lump itself then it will be stationary I'm supposing each one of these individually is stationary then you'll have a thin picture, this is where we talk about stationary things Imagining a space-time with a lot of arrows on it, that represents a vector field, and that vector field is expressing the stationarity of the space-time. You can shunt it along like this, and if it's stationary, then it pulls space-time along the arrows, the metric remains the same, and it's stationary in space-time. Nothing changes in time as described by the arrows. this killing vector that really plays the role of the partial d by dt, that one would use in the Schrodinger equation. The Schrodinger equation involves the d by dt, and that d by dt in a general relativity context, stationary general relativity context, describes this displacement, the intestinal displacement in this timeline direct direction. So that's That's a killing vector, and what we have here is a Schrodinger equation for each lump individually. We'll just go further there, we have, it's here, then we have it as an eigenstate of energy. That eigenstate is the time displacement of the eigenvalue of the energy. Let's suppose this is just a horizontal displacement, there's no difference in the energies. So here you have another, if you do it in the other position, you begin with the magnet state of this time translation operator, that feeling better. And because of the linearity of quantum mechanics, if you take any superposition, and that's also a magnet state with the same energy, it sits there forever, each one sits there forever. So you have a complete degeneracy, all superpositions are just the stationeries, each one individually. But now I want to bring in the gravitational fields of the lux. Up to this point, I've really been thinking of these as lumps sitting in the background. But I want to worry about the fields of the lux themselves. And the question now is, do we still have a stationary

45:00 state? Well, I want to try and indicate this schematically here. Here we have, first of completing it with something which moves it with an amplitude needs to develop with some other amplitude, and the movement will then shift it like this. And you'll see that what I think what is literally, with the expression state, with its own t by dt, when there's a superposition like that, you have two different kilobytes. Well, I should say, it's more serious than just having two different principles in one space time, because, according to the principles of general relativity, actually really what you've got is two seconds of space time, and each one is a space time of a lump in it, and they're trying to superpose those two space times. Now, according to general relativity, there is a principle of general covariance, which says that I don't have a general principle which tells me which point in the space-time is to be so to be the same in the space-time. In fact, we don't have such a principle. The principle general says that there is no canonical way of identifying points in the space-time. And that all comes back to the principle equivalents. It reminds them of the other people. It tells the gravitational field Uniform gravitational field is the same as physically as no gravitational field at all, and you take all the theories that are led to the principal general covariance, which is an important aspect of the theory which takes principal equivalence seriously. So that's the DR input we have here. That tells us that these are really two separate space-times. They're not too thought of as identified. But how do you do the quantum mechanics? Of course, this is the sort of thing that people worry about in quantum gravity, and they go to great rigmarole and construct them in huge spaces, and multiple spaces, and spaces of spaces, and so on. But they never really come back to talking about problems like this. Usually what happens is the only kind of identification of some deep identity operator would use to do it out to infinity and then have some... See, I need to boil over it because I need to say something about the state here.

47:30 Having it out to infinity is not too much help. So, there's a series issue here. My own position on this is to say, okay, I don't know how to resolve this problem in general. I think this is a serious problem, and I think it tells us we really don't know what to do. I think that if you take this problem seriously, and take the principles that we're depending upon here, if both one depends on relativity, we just come to an impasse here. That there's no way of treating this problem. But on the other hand, it seems to be a very normal problem, so we might do it in the lab, So my point of view here is to say, well, I know I shouldn't really identify these space times, but let's do it anyway, and try to estimate the error involved in doing this. So I do it as a sort of provisional thing, and then try to work out how much of a mistake am I making to make this identification? Well, I don't want to trouble you with calculation here, it's basically down at the bottom. The idea is to say, okay, well, Nature would really like to identify these things so that the pre-faults in which space-time are identified, but you can't quite do that globally. So what I'm going to try and do is estimate an error. And what I would do is try to identify them as best I can, and then try to see how the three falls in one space-time and the other live from each other. So I have the acceleration vectors in the two spaces. I take the difference between them and integrate that over space. And that's the idea. I might think of another prescription, but it's simply a natural one. And if you do that, basically, it's this left-hand side of this. I've got the equation, it's normally written down a little more, I'm keeping here, so you can see that. It's the integral of the difference between the acceleration fields, which is this, in terms of the Newtonian potential. I should start doing this all in a Newtonian approximation. Of course, general relativity is, to go the whole heart is going to be very difficult. And assuming you have a situation in which the gravitation feels weak, the spacetime can be treated as basically flat, but where one does have to worry about principal equivalence, which, in accordance with the suggestion from George Christian,

50:00 seems to be strictly ought to use some kind of formalism. But just for this error calculation, one just uses an eternal picture here. So I take the integral of the square of the difference between these acceleration fields. This expression has the advantage that if I add constant acceleration into it, it doesn't make any difference. So it has a certain kind of variance in its formula. And then I just integrate my parts and so on. I come out with this estimate of the error, which is essentially energy. It's the gravitational self-energy of the difference between the two mass distributions. So if you think of one of these lumps here, it's positive, and the other one is negative. So I have a positive mass distribution, and I subtract this one from it, so part of the negative one here, and I work out the gravitational self-energy of that difference, which, as I said, is what I come to in the calculation here. that's this, so the line in the bottom line here, delta, that's the error, is this gravitational self-energy of the difference between the two mass distributions. And what I'm saying is that that is an error in the energy. It's an energy, basically, an error in d by the t, according to the principal chronological mechanics, if you like, d by the t, which translates to an energy, as you see, certain eigenvalue equations, and so on. And so therefore, we have an error in the energy, system, and that energy error I can think of as being a measure of decay time for this new position. It's not quite telling us that this thing has decay, but it's telling us that just by comparison with things like unstable nuclei, where you say uranium nucleus or something, which is not quite a stationary state and the fact that it's not quite a stationary state is related to the fact that it has an error in this energy where the time, the decay time and the energy uncertainty related by this formula here decay time is of the order of h cross divided by this energy uncertainty but for an unstable nucleus it wouldn't be gravitational and here I'm saying it's a gravitational contribution which is an irreducible thing you can't get rid of it

52:30 general principle of general relativity, and it's something which is not present in a normal way of looking at quantum mechanics. It's an input from another part of physics. So I think one of the things I like about this way of looking at things is that it doesn't bring in arbitrary parameters. It's also not a very ambitious scheme, I just quote a conservative in a sense, it's a minimalist scheme, because it doesn't actually say how the reduction happens. There are no dynamical equations which says that this superposition does something slightly different from the Schrodinger equation and ends up either over here or over here with certain probabilities. It doesn't do that. All it says is that there is a lifetime for this kind of superposition and that estimate for the order of that lifetime you didn't know this formula here. We work out the gravitational self-energy as a difference between the two Each is stationary, and that gives us EG, and then we take H bar over EG. This is a kind of schematic picture of what happens to show you the problems involved. Here we have the lump in one location, and you have a superposition now between these two locations. Somehow you have to superpowers these two spacetimes, and that's where the problem arises. is how do you do that? The problem with quantum gravity people are always fighting with. It usually leads me to some very abstract way of looking at a problem. But I'm just doing something practically rather simple-minded and not dependent on the thoughts and the performance and so on. I'm just saying that there should be this decay time for that superposition. And the idea is that it likes to be a stationary state so that this superposition will decay into what the other stationary the other. Whereas the whole thing is not the stationary state because of this contribution and this energy uncertainty. So that's the idea. I should say, I want you to make a comparison with certain other ideas. Kerala Hasey really is the person for the longest who tried to bring GR, he claimed that general relativity is the source of the state reduction issue. Iyoshi, Northern Hungarian, that's very similar to what I'm saying, but not quite. In a way, it was more ambitious than what he was trying to put a dynamics in. Other people like Kibbutz, that's a lot.

55:00 But usually what happens is that they have to introduce some other parameter, whereas here, there isn't any other parameter. It's just things we know about already. The gravitational constant, Planck's constant, perhaps the speed of light. Well, in fact, the speed of light doesn't incorporate into this, which is perhaps one reason why you can look at the Eutonian situation, because the speed of light doesn't enter into this formula. This formula just involves gravitational constant down here, it involves Planck's constant down there, you know the cc in that expression. If you want to know these sorts of orders of time scale involved, perhaps one's first reaction would be surely this is ridiculously tiny, these energies are absurdly small, and indeed they are, if you work out this formula, you find that time scale is often quite a reasonable time scale. It's like many, because time, ordinary times, are absurdly large by comparison with the Planck time. So Planck time is 10 to the minus 43 seconds. So from the point of view of general fundamental time, 10 to the minus 43 seconds is the fundamental time. whereas if you're only about a second, well, that's 10 to 43, that's 43 orders of magnitude larger than the black planet. So just a reasonable time in our ordinary scales is ridiculously long, and therefore corresponds to the ridiculously small EG. So if that EG is ridiculously small, there's no argument. In fact, we just have to look at the figures. and what I've done here this is an old slide I'm sure you've all seen it a couple of times this is just a sort of schematic thing where I consider the masses as uniform spheres, this may not be realistic but it's not if I consider the spheres as just the uniform mass and I work out the the only point that's actually worth making here is that this is as I move the lumps from coincidence out to contact with this contact point. And this is the energy involved. And then from contact out to infinity, you'll see that it's only about twice as much to contact point, all of the out to infinity contributes only about half as much as moving to contact point. So you don't gain much. Once you've got them from coincidence to contact, you don't gain much, you'll get them right out. This speed differs from certain others. In particular, the Percival scheme, and in this scheme, the reduction gets more and more likely to fall apart than they are, and quite a significant impact on the surface of the study.

57:30 In this scheme, just taking these things as uniform stairs, because they're not fair, but let's not do that. If you take a nuclear arm as being a uniform classical object of a radius of a fermi or something, then you find that the decay time has super-stated to a few billion years. So that's fortunate. We don't see any conflict with things like the neutron diffraction. People tend to be like two weeks and so on, and they definitely appear with each other that neutrons really are in two places at the same time, but only for a very short time. of years. So there's no conflict between this and those neutron experiments. If you take a little drop of water, I'll just put the figures here, 10 to the minus 5 centimetres in radius, the decay time would be a matter of hours here, for a micron of 20 to the second and 10 to the minus 3 centimetres of an ingredient per second. So you see the turnover here, there's a kind of fifth power involved, so 10 to the radioactive here. So you see that this is where you start to see the effects. The important point is here, is of course, well I haven't talked about environment in the internet, it's very, very relevant for all this, because if you actually had a lump, which you put into a suit position to the patients, each one would be accompanied by a different environment. And you would have to worry about the environment, the difference between the, you know, the mass distribution in all the particles in the environment, and so on. And my estimate would be that in almost all situations, it's the environment which plays the major role. So, when people do these environmental decoherence calculations, I would probably agree with their answers, because, okay, the light of measurement is... I mean, I can't actually use this discussion in the environmental case, because I can only use it in a very simple situation where I'm looking at a superposition in two states, each of which individual is stationary. Whereas in the environment you've got particles chasing around all over the place and you don't have a stationary configuration. So I don't really know how to treat this correctly for an environment. But my guess would be

1:00:00 that there are so many particles involved and you don't need much displacement. One particle for another to give you a significant fact So I would guess it's very likely the major effects is in the environment. Indeed, as the environment would be coherent to people would say, it's the environment, if you like, that does the reduction and carries the system with it. Roger, when you say environment, do you mean here and just mean non-validated environment? Well, I think I mean here, I'm talking about it more in the context of what the environment would say, that you have some gas or something running around. It's certainly not... I mean, the gravitation is only irrelevant. I'm not looking at, say, a planet here and a lot of stars. I'm not looking at gravitational forces being important in this. These are just ordinary electromagnetic forces, probably. I think it's a pretty idiot bouncing off. and so on. And if you have a thing here and a thing here, when the air molecule is in and here bouncing out, if I move it just slightly, those air molecules are going to go up in quite different directions. And when they start thinking the next molecules, they're going to spread out in no time. And so all the molecules are going to be in different places. And so if I could treat them stationary, which may not be fair, maybe it's fair if the motions are not very fast, and so on. The reduction maybe would happen fast enough that you could treat them stationary. I haven't sort of looked at that carefully, but it's something that maybe one should, I'm sure one should look at it, try to estimate what the reduction time would be from, say, just a gas. But yes, those things are not gravitational. The gravitational effect only comes in in working out this gravitational self-energy. and that's the thing people often worry we'll show you the gravitational forces that are smaller than the other forces we're talking about of course they are, but one's not looking at the gravitational force aspect one's looking at how the mass distribution affects the structure of space-time and therefore affects the structure of quantum electromagnetic effects wouldn't enter this world they don't affect kilomaxes in this way which is affecting between the electromagnetic fields

1:02:30 not do that, except indirectly through its own energy. But that's a much lower-down contribution. So, it's very much a gravitation thing. I hope that answers your... I should make a comment about the experiment. The original version was this one here. I was in Innsbruck, and I talked to Anton Zyla and his group, and I mentioned this thinking it was a totally crazy idea that it would be way out the... way beyond the capabilities of present-day experiments. And I was very pleasantly surprised that they didn't simply think I was in that case, but they took me seriously, not just took me seriously, but they thought it was an experiment that was perhaps doable. I should say that one of the original contributions to this idea came from Johannes Duffrich, who suggested using something like a MOSBAR-type crystal. The idea is that here you have a little crystal, and that if you knock it or something, and even a mass bar crystal is the individual nuclei, which sometimes they decay, and the recoil is taken up by the entire crystal, not by the individual nucleus. So you think of them as all locks, in a sense, that the recoil is spread up over the whole object. So that's what I'm taking advantage of here. But it's not a nice wire crystal in the same sense that I'm worrying about the decays of individual nuclei here. I'm imagining this is a shortness cat and I'm trying to hit it with something. And this something could be a photon. So let's imagine it's a photon here, this experiment idealized experiment in the bottom here. The figures that I got from the group were, you might try something with a crystal of about 10 to 15 nuclei. vary these figures, depending upon what's appropriate in the experiment. Let's say 10 to 15 nuclei, and a very rough calculation gave the answer that if you displaced this thing by about a nuclear diameter, so you have a rough sort of schematic picture

1:05:00 here with a nuclei in two positions, blue and red locations, where they're sort of moved like that, and a rough estimate of the decay time, according to the scheme, is a tenth of a second. So it would be quite feasible if you could do an experiment which keeps this crystal in a superposed state. So here we have a photon source, leaves splitter, so it goes this way and this way in superposition, the part of the photon state which hits the crystal, knocks it here and comes over here, and slightly displaces it. Now you've got to keep both parts of the photon state coherent for about a tenth of a second, and then release them, and they come back again, well this one said comes back slightly ahead. At the meantime, this crystal has been displaced like this. There's a spring, roughly speaking, in suspension, which brings it back again in a tenth of a second to its original location, but for that period of time So according to me, there's a reasonable chance it would go to one or the other. If it goes to one or the other, then everything it's entangled with, in other words, the photon, must also go to one or the other. So the photon, if it's received its... If it goes into the original position, then that means that the photon has gone this way. If it goes into the displaced position, that means the photon has gone this way. and it does one or the other, and when it's released, it comes back here, and now there's only one beam, so that this puts the photon's wave function into these two equaling, those two alternatives. The detector placed here would therefore half the time detect the photon, it's an ideal detector. Whereas if these two parts of the photon state are kept coherent, because this thing is not reduced to one or the other, and then comes back, it's the superposition is preserved, then you have these two beams coherent, as long as you've got your path lengths appropriated and so on, they will combine and go back up the way they came. Or you could do rings and they always come this way, one or the other. But they will always do one or the other, designed it to do. So you can, in principle, tell whether this has done its reduction. Of course, you can't distinguish that from other things. There might be environmental

1:07:30 incoherence of some sort. There might be an air molecule which comes a bit in and spreads its wave function all over the place somewhere. And you might land yourself back with a standard environmental incoherence picture, which would in any case destroy the coherence. There's There's no question about that, that you could imagine the covariance is destroyed from some other way than the one indicated or suggested here. One of the main problems with this experiment, as it stands, is that to give the crystal enough of a kick, it has to be an X-ray photon, and it has cavities which will keep an X-ray photon going for 10%. that's a major challenge and that probably part of the experiment is outside technology although it's sort of a bit of outside technology but what we can do is to try another version of the experiment which is looking out in space the experiment is done on one space platform Now, let's say Earth-diamonds are away, you could make the distance greater if you wanted, it might be useful. Let's say Earth-diamonds are away, then the length of time it takes to go out here and back again is a 32nd, and that's your cavity, your space, with one mirror. Of course, even that, maybe one mirror is a challenge, and people often quizzing on this, is if you realise that mirrors are used for X-rays in space are grazing mirrors, Well, I do realise that, but there are certain kinds of mirrors which are not crazy mirrors, which do exist. So, one would have to use that kind, but it's different from what people use in astronomy. So, this is one version of the experiment. And my colleagues here, it's done with Bill Marshall, have been doing great things thinking about this. It's certainly a possibility that one might end up doing this experiment. One of the troubles with doing space experiments is that people who do space experiments have to be prepared to wait for a quarter of a century or something, probably before anybody has an experiment. I'm not sure I want to wait that by myself. I don't know whether my colleagues do. And one idea, I guess it's Will's idea, which seems to be struck me as a very nice one, which in a sense gets us back possibly to the version which I just made.

1:10:00 The idea here is that instead of using an X-ray photon, you use a much lower energy photon, but you arrange it existing many, many times. So you have a slightly more complicated situation So you go backwards and forwards, maybe a thousand times or something, so you can get the energy down, a thousand times is what you would need to put an energy down, and you see the total impact, this happens all rather rapidly by comparison to the swing back time and so on, so not so different. and then you've got an effectively much more energetic photon, even though, in fact, the photon is far less energetic than an X-ray photon. So maybe one could do this in the lab. And certainly that would be a great advantage if we didn't have to depend on people spending things up in space and so on. Okay, so that's the general idea of experiment. And I hope that this group will move forward and it will be done. Of course, there are all sorts of issues which will come up with other forms of decoherence which will take place. And somebody may come along and say, suppose the experiment works, does everything I claim it should do. And they come along and say, well, I've just done a calculation looking at fluctuations in the gravitational field and it's clear that there will be decoherence because of the fluctuations in the gravitational field and it's no different from anything else in quantum mechanics. But you could take that position. It seems to me that that sort of abandering hope, and after all, the measurement problem is a big problem. We want to resolve it, we don't want to push it away by trying to do an explanation for this. When I was talking about this in Holland, somebody very obligingly there said that, well, we can get like Lorentz, because Lorentz never accepted special relativity, Since he's a Dutchman, I was quite happy for him to say this. They don't accept the special relativity, and it could be a bit like that. You see people who are old-fashioned and they insist on going to old-fashioned quantum mechanics and refusing to look at a new point of view, which is, of course, the analogy being with ad-stands,

1:12:30 the way it looks at special relativity. I think that's a bit far, but that's a nice thought. I think I wanted to end, just briefly, with another comment. You say I'm allowed to put on endlessly in this lecture, which I really don't. Can I make my comment? The comment is to do with, well, you see, the conservatism of my approach here, which is that... Let me make another comment, just as to do the experiments. See, what you want to do There are different types of crystals, different sizes, different energies of the photon, all sorts of things. Vary as many parameters as you can think of and see, okay, if you do get decoherence of some sort, do these. Does the gravitational self-energy of a difference expression give you the right answer when you vary all these parameters? Can you pick up this particular effect from the others because you vary other parameters? Well, one thing to vary is the spread in the wave function. So you see there would be a much greater effect here than there would be here. This leads me to something which I didn't go into, which is actually important. part of the whole process, and that is, how do you talk about those states being stationary? Because individual, if you talk about, why can I talk about lumps, you see, rather than those lumps are made up out of quarks, or that, and the protons and protons and quarks, and quarks are supposed to be quite powerful, so if I move two quarks, even if there's a tiny bit away from each other, I'll have an infinite self-energy that can be reduced instantaneously, and there will be no quantum mechanics. Well, the answer is there, that are not going to be in a stationary state. So what you have to do to apply this system is to, and you can do the calculation here, is to try to work out the wave function for the crystal. And say, if it's stationary, and that would be a complicated thing, because it would involve all the interactions, electromagnetic interactions and so on between particles, which have to be taken into consideration, which would be stationary, and then you have to work out the expectation value of the mass distribution and take the difference between these and two different locations.

1:15:00 You also may have to take into account a correction term from the Newtonian gravitational potential, which would be relevant. It's not so relevant here, because once you're looking at one solid object, you might have states built up on separated things, and you don't have to worry about the Newtonian contribution. So one of the things you have to do is to solve what I thought was the Newton equation. And my colleagues, Paul Hall and Irene Morris, have been doing a good thing for that. I just wrote them down here, where you have the trading equation of the natural term, which is a new term of potential. And you look at stationary states, stationary solutions of the Trojan-Bukin equation, and those are the states that might represent everything in terms, and those are the states that nature likes to reduce into. whereas the superpositions of these things would be essentially unstable. The only other point I wanted to make was to do with the big point, but I think people would probably like to wait for someone to ask me this question. The problem, of course, with any realistic state reduction scheme, as I'm suggesting here. It's not really a scheme because it only has a limited applicability in cases where you have a superposition between two stationary states. But in general, you might worry about how you make a reduction scheme which is consistent with relativity. People always bring this sort of picture up. But you have an EPR situation where it's going way to the light, say, and you make a measurement here which reduces the state. You have two different reference frames here, A and B. So going to B, these things are simultaneous. So this measurement reduces the state there, and this measurement is looking at the state having been reduced by this one. Whereas if you look at it from B's point of view, it's this one that makes the measurement and reduces the state there, and then that reduced state is looked at by the other one. So if you want to have a real picture of what's going on, is a real phenomenon and where it's to be consistent with intense special activity where you've got a problem here. And so people often give up at that point and they say, well, let's talk about phenomenal artistic speeds.

1:17:30 That's usually what people do, trying to make reduction into a dynamical thing. Or they say, well, this is telling us that we can't take a heuristic picture. So my other position on this is, it's really a different talk, I shouldn't have slapped this on the end, so let me slip it in on the end, if people want to ask questions about it, and I'm happy to talk about it. This is the constant teleportation, the whole question we've talked about here. It's just a nice example, let me just say it quickly, I'll say it very quickly, if people what to talk about in our heart and back to it. This is this question about, here you have a state of a spin-half particle which has been given to Alice. Alice doesn't know what that state is, but Alice's friend who put it in a box somewhere and said, look, there's a particular state, the spin-half particle has got a point in some direction. Can you please send that to Bob over here? Normalize hooked it, but looking at it really good because we don't need to make it in one direction or another. So Alice has to send that off to Bob without putting it in a parcel and sending it, which of course is the easiest way. But the conditions of this problem are that somehow the conditions are not right for actually sending a quantum state. All you're allowed to do is send classical information. But Alice, fortunately, has a suitcase in which is one-half of an EPR pair, starting from this zero state, and Bob has another particle in the EPR pair, another suitcase. What Alice does, he takes this particle, brings the one with my suitcase, and puts the two together and makes a measurement, of which the four eigenstates are these so-called bell states, and gets their four different possible answers, 0, 1, 2, or 3. She then sends the number 0, 1, 2, or 3 to Bob. And Bob, if he receives 0, he leaves his own suitcase alone. If he receives 1, he rotates 180 degrees about the x-axis. If he receives 2, 180 degrees about the y-axis, and 3, 180 degrees about the z-axis. And if you work it all out, you find that inside Bob's suitcase alone, is the stake which Alice received from her friend. Very remarkable. There's nothing wrong with it. In fact, the quantum mechanics says this is what happens. And there are now experiments.

1:20:00 And shows that this actually doesn't work. So it's called calling teleportation. But the puzzle for me, if you like, is that here you have, if you want to describe mathematically the state, you've got a point on the sphere. To describe a point on the sphere, you need an infinite number of bits. And somehow this infinite number of bits has got through to Bob. They're not bits that can actually be read off, because you can't take the state and say, where are you pointing? You can just measure it this way or that way. However, it does seem to say there's a reality about the direction, because finally Alice's friend might have revealed to her what the state was. As a matter of fact, the state was pointing it that way. And so Bob can then check out and say, oh, let's see if you're right measuring that direction. Yes, every time this experiment is performed So it looks as if there's something real in a physical sense. It somehow got across from here to here. But it kind of got across simply through this classical signal because there are only two bits here. There's an infinite number of bits needed to describe that system here. But if you look at the picture, you see, where is the sort of information, in a sense, going? Well, it's got to go... There is, in fact, this connection through these two legs here, is being zero. So there is a connection. It goes up there, down there, up there and up there. The only problem with it is it goes backwards in time. And this is in fact what some people call quantum information. But I think the trouble with the word quantum information is that it suggests information that you might actually send a signal with, which it's not. So I'm calling it quannel. It's the name sometimes that is, even though it doesn't actually solve a problem, it enables you to think in a way, and if you have the information. So I'm saying non-quality information, I'm quoting something else. It's quite a moment. There's nothing wrong with quite a moment going backwards in time. In fact, it doesn't go anywhere. It's just a sort of connection between these things. These kind of links can go backwards in time equally as forwards in time. It seems to me that the sort of picture of reality that I like to have takes quite a moment seriously, and that if you don't have a

1:22:30 realistic scheme in which reduction is a real phenomenon, as a real phenomenon, but it's not something which you can use to send messages directly. You can only use it in conjunction with ordering messages, and it can. It's a central part of quantum computing, for instance. But it's not something by itself which can be used to send messages. Now, I haven't been able to work all this out as a scheme which makes some kind of consistent ontological sense. I think in any case, I've been to have a non-local picture in some sense. But this in a sense is doing that connects things in ways which are not causal in the ordinary sense. But I think one needs that to make sense of going to have a reduction as a real phenomenon. This is going to play an important role. I think I'll start on that one. Thank you very much. So thank you. It's just fine to have that extended presentation. So we're open to questions. The lead part of it. My general approach is that I'm very happy with many words. and I think many paradoxes which you presented here do not exist in many worlds so I think this gives motivation to many worlds Do you agree that you're forced onto a theory of consciousness to make any world's worth? In many worlds I do need to talk about consciousness I don't think it's so much problematic I don't think we have to know the exact structure of the brain and everything. It seems that kind of general things about consciousness are enough. And people here might help to say how human beings prefer basis. One of the serious objections was that there is one picture which seems reasonable and then in another picture, in another basis, in complete nonsense. One picture is stable, it has a stable branch, and the coherence tells us which branches are stable.

1:25:00 And so it picks up by physical processes, particularly. But may I just concentrate on, in fact, what I would like you to stress, more motivation for your approach, because I think there is a serious motivation for another approach. you may be clarified probably not maybe not understood correctly but you have trying to simplify your motivation then you say that there is no theory of quantum gravity and there is no way to have a superposition of two masses we don't have a theory how to deal with this how to deal with the space-time And then they went out just to say that there is some process which collapses to a particular non-immiscible position. But in Yossir you say that this process happens when this separation is relatively big. And there are some special parallels. Now we know that if the masses are small then there is no collapse because we write interference experiments with buckyballs, which are not so small. So, in the end, there should be some theory of quantum gravity. Somebody should write an equation how to describe, because buckyballs are a gravitational field. So, somebody sometimes will have to write an equation for superposition of masses, for what will be the spacetime in this case. When this will happen, if it will be possible for small masses, why not for big masses? And then it seems that there will be no motivation to say that this superposition of big separation of masses do not exist. Yeah, the problem is the conflict with the principles of general covariance principle. But it exists also for small masses. Yes, but the measure of how big a problem it is, is a very small measure. On this scheme, you see it. The problem is different, but in the end, or maybe you say that in the end there will be no final theory. But if you believe that there will be final theory, there should be description even when there are small masses. Sure. But whatever small, this problem with two vectors will exist always.

1:27:30 It will be a very small problem, but it's the problem which has to be solved. So you're saying it will not be solved at all, or it will be some new fluctuation field? No, I'm not saying, you see, the point of view here is that I can get away with saying certain things about chemical theory. When I say it's a minimalist scheme, I'm not saying, well, we can't do anything until we have the full quantum gravity theory. I'm saying we can do certain things. We can make estimates of the timescales for decay in these schemes. I'm saying that without having a comprehensive theory, I can still start saying things. And I can take these cases where the difference is very small, and I buy these ideas, and I find the timescales of decay is enormously long. Take those buckyballs, for instance, and I haven't done it yet, but the timescale can't be less than millions of years. Something like that. And certainly the experiments are only done with a very, very... on that sort of, those terms are very brief here as they are in secret position. So it's... Yeah, you can apply it to those cases. You just get the answer that the experiments would agree with what I claim. It should be. You have to have a very delicate experiment, like this one I'm suggesting here, in order to have the gravitational effects that you would see a significant contribution from gravitational self-energy. I'm not sure I've answered your question, but I'm not sure I understand it fully, we are more interested in the point. So may I just put your point out of that? Well, maybe I'm not understood exactly the motivation. How it was... No, I think the problem is if you're happy with many words, then you don't have my motivation. No, no, but... Why do you need to go to this problem for production? Now, a specific motivation for, because I understand it's a crucial point that there is this difficulty when to write down a space-time and there are two masses in the superposition. Yeah. This is really the crucial point. Now, in the difficulty, I don't think the difficulty will become smaller when the masses are small. maybe the effect the world cannot be approximate space time is one space time if we don't know how to write the proposition of different space times so we should find some theory it cannot be even a proposition of slightly different space time

1:30:00 it seems to me that this is a very negative approach but you just say well until something is going to have a theory a full conigraphy theory which can accommodate this kind of scheme we can't say anything. Is that what you're saying? And I'm saying that we can actually, we don't need that full theory before we can actually make some estimates and so on. Okay, even a tiny little displacement, you know, with bubble balls, there will be a contribution. And so I say there is an energy uncertainty in those experiments. But that energy uncertainty is so small that the time scale for the decay will just be and obviously not. I mean, it's still there. I'm not saying you wouldn't use this without this. If I understand that according to your collapse theory, it will take a long time when the superposition of when I have a superposition of buckwheat it will take a long time to have this collapse. But during this time, it seems that we don't have a theory how to write down what was going on. That applies to anything. You can't do anything to this. We don't have a proper theory which includes the But it seems that this was a motivation for the collapse, because you said it's not acceptable that we don't have a theory, or the motivation was different. If I understood you correctly, the main motivation for this gravitational collapse is that we don't know how to write theory of masses in a superposition, and since they collapsed to one, then there is no problem. Yes, but in this case, it's serious that we don't have serious. I mean, in the case of the lucky balls, it's not serious. Because the energy uncertainty is very small. But still, it's not serious. See, I'm not looking for a theory. But the fact that it's small, the small difference, even if we don't know the timing of the theory is not consistent, we just don't have axiom how to write it down, I think it's still not a destructive issue, even the effects are very small. I'm assuming you apply that principle so broadly that you couldn't do any physics at all, because we know we don't have a theory which incorporates gravity and quantum mechanics, and these phenomena are present, I mean, you know, even at a small level. So you can't do any physics. No, no, I will not use the fact that you don't have this theory to introduce some effect to avoid this difficulty.

1:32:30 I would say it will be time to have this theory. effects. We don't have a full theory to accommodate those effects, but they're going to be so small that we don't worry about it. And we do that in two weeks all the time. So I'm doing that here. With the buckyballs, you can make a rough estimate and say, okay, the fact that we don't have a theory which includes the gravitation through the quantum mechanics in that case is not going to be worried in that case. The estimate where this will come in tells you the timescale of the new years of years that you've learned about it, and you're not looking at that. So I don't think I got to your point. The lack of a theory doesn't matter often, because we can make so-called rough estimates. The fact that this is the theory we then have is in the form that we then have. Whereas here, in fact we're going to make it easier. Because we can make estimates so that this error in the end, the area that is involved in the clash between the principles is actually of the order of this location. Do you want to say that you have an argument that whatever theory will be, it will not be able to cope with this big superposition? We don't have a theory, and we don't know how to write it down. If the small object is not important, the big object is important, but maybe the theory will come with it. They don't know the theory. Is it possible? It's possible. I'm not saying that's possible. But I think, you see, it's only a kind of viewpoint that somebody was happy with one of the other explanations you put forward. I think your point of view is consistently saying, Okay, you like many worlds, and you've got to trust them to that, and so you don't... I come along and say, no, no, I don't want to stay with that. Well, why should I bother? I don't want to stay with that thing. So I can do it with my consciousness remissioning, not remissioning state, but choosing what to do. And that leads us back to the why I'm not happy with many worlds. That's an issue. So we have four people in a queue. Brown, Troy, Christian, Simon, Saunders, and this gentleman. Now, does any one of the four of you want to talk about just this topic? Because if so, we should probably take you first. So Harvey and Joy are both on this, exactly.

1:35:00 Is that all right? I'm going to try and put Lev's point in a slightly different way. I think it's something that probably bothers a lot of us in this scheme. if you're you seem to be saying that if you believe in the world that we've got a relationship it's allowed to make it better in the world I don't think I'm saying that can I just say what seems to be consistent with that is the fact that you're saying look we're trying to understand what it means for mass to be in a superposition of being in different places and the effects that has what kind of space-time is involved and how do we understand this in the context of general covariance. Now, it seems to be that you're saying that there's an exceptional problem that speaks an exceptional problem. Now, we want to get rid of this exceptional problem at some practical level, so you can just relax. But it's as if God is willing to accept incoherence up to a certain point. No, no, no. But, you know, Lev's point is that positions at the level of the neutrons, then there is a very small scale of which the incoherence is occurring. Yeah. But it's very small, and it won't have made it interesting to any experiments. But why isn't that incoherence fact? Well, why isn't that a theory of coherence fact? If there really is an incoherence in the notion of a superposition of bodies in different places, or let's say a superposition of one body in different masses, why do we allow that incoherence to occur at a very small scale? Why does the scale come into it at all? I'm not lying, it's just that the fact that I don't have a complete theory isn't worrying at this point. I certainly take that as a view that there is a complete theory that we don't have yet, somewhere up there, if you like, which tells us what to do in all these cases. And that that theory, if we knew it, we'd go away and we'd say, oh, well, this term is small, we didn't know that, this term is small, we didn't know that, and oh yes, it won't reduce in the timescale that it's coming.

1:37:30 But not having that theory, it's a bit hard to, you know what I mean, it always seems like in the world it's the hope that somehow there is some theory which says what consciousness is like and picks out universes which look like universes and so on so it's all depending on some hope that there's a theory somewhere which nicely makes quantum mechanics make sense so I'm saying ok there is a theory somewhere but my theory is much closer to what we actually see in the world because I'm saying you do quantum mechanics experiments you see in the world the reduction happens I'm saying that this theory would be a theory of what the world actually seems to do. We don't have it yet. But in fact, a fact that we don't have it yet doesn't mean we can't talk about what it might be like. In your case, the deep theory would allow the superposition of a small factor. I mean, it's an approximation. It would always mean an approximation. The idea is you don't allow small inconsistencies, but that you probe to find the good theory which retails them by looking at the place where the inconsistency is testable. That's the answer. So, sorry to interrupt, but I still don't want to say it for a black talk. You said what I wanted to say, but I put it in a different way. The other is defending himself very well, but I would like to just do three different things. Admiral Shibode is very fond of saying that physics is an art of approximation. There is no physical phenomena that you analyze with some complete consistency with even existing physics. So you always have to make some approximation here with that. Now, the point that we put forward by you and other and so on, but the problem that both of you and some other people are having is because you're looking at a one fragment only, meaning quantum mechanics. There are two fragments, and then many other people are trying to construct a full picture. Now, if you look at this full picture from this one factor, which is complete superposition and the prejudices which go with it, then you will never see the issues that Roe is addressing. But if you look at it as a complete theory, which could actually allow a total superposition, without non-fap superposition, I can conceive a theory that allows non-fap superposition for small objects

1:40:00 and non-fap reduction for big objects. So since we don't have a theory, that kind of theory can exist. Let me make another point, which is related. Quantum mechanics, as we know it today, depends on linearity being exact. That's the way it's formulated. To me, this would be incredible, because we've seen theories in the box. I mean, you term in gravitational theory, the forces add up linearly. We now know that's an approximation. It's an approximation in a very subtle kind, because when you bring in temperature space-time, it's not that they add in with some nonlinear term. It's really quite different perspective on the whole problem. So I would say, I expect to see something a bit like that. That the linearity of quantum mechanics is not a permanent feature. I don't see any reason why it should be. And it's the linearity of quantum mechanics that's forcing us into worrying about cats and so on and so forth. So I'm trying to say that there's a certain level that the fact that linearity is wrong will start to become manifest. And so I don't quite see why one needs to hang on to the linearity and push the problem somewhere else, which in many worlds one is trying to do. So I guess I'd make it to the beginning, that somehow all these other points of view seem to depend on having a theory of consciousness and that I find very incredible in the sense because not just we don't know what consciousness is, it's just that it's such a vague, and how do you get these precise laws? It's not just that the U power quantum mechanics is very precise and accurate, but also the way that the probabilities are calculated. And I should imagine, I haven't gone into it, but the experiments of quantum mechanics probably, the confirmed quantum mechanics are confirmed with probability law as much as they are unitarian. And that probability law is a very, very precise thing. And if you're going to get that very precise thing out of something about, well, you know, consciousness isn't perceived something or other, not something or other else, I just find that pretty incredible. so it's just to get those probability laws out in the precise way that we do that's not linear there is something very accurate and precise

1:42:30 going on under there which seems to me to be a mathematical approximation something which neither of them are really true so linearity is approximation that you find often if you have something that is nonlinear except for a wide range you might find linear approximations work extremely well. I mean, in any case, since we don't have a theory, there are two options. Your option and your option. So once you try out all options, what's wrong with that? We do an experiment, that's what the idea is. Since we don't have a theory, we don't have a difference about the theory. Yes, that is. This is not a good thing from the theory. Yeah. Yeah. Do you want the ground one or the space one, I don't know if you like? Ah, either one. The important thing is... Is this good? Yeah. Okay. The element that has to move with the mirror. The mirror? Yeah. This one here? Can you shift it up a little bit? Okay. Okay, the requirement for this object is that its momentum has to be well defined such that the impact of a single photon will displace all the atoms over a certain distance. So the uncertainty in the momentum must be small compared to the impact of a photon. Can we talk about the error? Yes, right. So there's basically a error here. Yes, but the mirror must be initially prepared with momentum smaller than momentum in terms of the problem. Otherwise, it would not be in different spatial states in terms of this problem. I mean, you're right about the uncertainty principle as applied to the... Because it's the same as the argument between Einstein and Bohr, where Einstein suggests take the double-slip from the network and put the slip on very sensitive divides. If the electric goes this way, you could measure it. But then the initial position of this sheet must be searched that momentum is well defined compared to momentum, and therefore the position of the whole world must be divided and the experience washes out. the momentum of the crystal without eluding much, because it's got lots of...

1:45:00 But then the impact of the momentum of the proton will not displace the distribution of each atom significantly. Yes, well that's the idea of acting like a monster. Now if the initial uncertainty of the crystal is larger than the impact of the proton, then after this impact you cannot have each atom displace, because it will spread the momentum and it will propagate over a large distance. So the point that I think that worries me a lot is that if this element really experiences the input of the photon, then it cannot be part of it in front of it because its position will be undetermined within the wavelength of the element of the particle that is it. I don't think that's right. Because the momentum could be quite large, certainly by comparison with the momentum of the photon, without it moving much. Momentum means that from that moment, there is an uncertainty in which direction will move. Yes, the uncertainty in the movement is very small. initially, at the moment you just initially, but then it hits, this photon adds up to this momentum. But then, still, the consuming momentum could shape this whole object in any direction. Because, again, the effect of this single photon is not strong enough to force the whole object. And in one direction. Well, why? Because when one does Mothback experiments, you have that sort of energy, isn't it? Yes, but that is not part of the infirmity. Jonathan uses MSR crystal as part of the infirmity. It's very important that you use the momentum pinster of the photon here, but at the same time you want to infirm the photon. Why is it not different from our mirror? The mirror is better. The reason is that they don't entangle the photon. The mirror must have such an uncertainty in momentum, such that position can be well fine, But it doesn't have a record of the impact of the problem, otherwise it wouldn't become entangled, and that's why, if it doesn't make it entangled, that's why the trust going to come to work. I mean, it took me a long time to answer this one. But I think it's... I think it's something we should talk about after, but I'm not persuaded by your worry.

1:47:30 Well, I think it's identical to this argument of Akshay and Borg there. And if you want to make the informant or sensitive to whether the part would take one or the other army, you lose the resolution that it needed to make the informant. Well, certainly if I measured where this was, of course, then I would lose the experience. That's the truth. I'm not doing that. I'm only letting it swing in the company. Thinking, okay, it can be a momentum state, it's a long train, you see, like this. And so you can think it's a superposition, it's position is a superposition of a lot of different places. And so, if you like, it's a superposition of a lot of impacts. One hits it, and then a little while later, another hits it, another hits it, another hits it, another one. It's a superposition of all those. And then the movement, okay, is a superposition of that, but since they go, they go, and then they go like this, they come back again. together. And so then when the photon is reflected, it all comes as itself. At least thinking about it in detail. But my feeling is that it's not a problem. It's a problem, you need to worry about it. But my feeling is that it won't ruin the experiment. but I mean that's there needs to be something else sorry there's a nice exchange I think it's not often I see one sound about a conference in New York which is a conference where a question depends what is coming up physics in a second as well can you just speak back sorry yeah I'm just referring to an email exchange recently about one of the major problems of physics There are probably all the super-stream theorists, Stephen Gross in particular, and that's not probably the super-stream theorists. And they then followed a lot of typical, you know, staying back and forth, people say, no, no, no, that's not the mental illnesses and so on. But I was very struck by Lee Smolman's complaint, after four or five interchanges of this. Because everyone was saying on the side, well, of course, we don't have a theory of quantum gravity. And Lee's complaint is, well, look, why do people constantly say this, indeed we do, loop quantum gravity, with various types of solutions. I thought it was the screen people who said they had a theory. Sure. No, everybody's got a theory, but everybody, they believe. Well, that's right.

1:50:00 But it does seem that loop quantum gravity has lots of features that we've argued for over many years, and we should be doing quantum gravity in any dimensions we should be looking We do have an exact theory. we have various kinds of non-interpreted solutions we don't have a low energy calculation theory, that's true we do the string theory but it seems that we actually have something like a consistent theory which we can't calculate within the perturbative region and that then makes one think that the claim that somehow there's an incoherence in the marriage with quantum mechanics and general relativity isn't quite right has now become too sweet for the claim. And I think if I look at part of the argument that you've been presenting, I suppose I, let me put it in these terms, and I think I've probably made a mistake in a way, which I hope doesn't knock my whole complaint into the water, but let me put it like this. We don't have so much of a problem with general covariance, and the majority has presented general covariance on the theory of gravity, in which we cannot re-identify space-time points in a simplistic way. But that doesn't seem to be the problem. What we do have in the is well-defined So the specific problem that you're addressing really is that rather than general covariance per se. And then one thinks, well, gosh, how does that translate through into the exact solutions that we do have in quantum gravity. We have forward quantum gravity and limit quantum gravity. And I suppose then the answer is, well, we don't have a Schrodinger equation, or we have a Ludo-Durgo equation, and what we have are some positions of three geometries, or functionalities of three geometries, not the thing that we're talking about. Yes, it's just abstractly superposed. There's no way of saying at which point we don't even try. Indeed we don't even try. But now it's getting a bit worrying Because it's not general covariance, because we can deal with general covariance. It's to do with inequivalent... Sorry, I mean, you can't think. That's a very weak general covariance. Very weak limit. Well, this is a big argument. I mean, it's a diffamortic covariance theory. Now, diffamortic covariance means that the only method by which one can re-identify

1:52:30 is in terms of qualitative features or some sort of relational constructions out of fields that are similar and one just doesn't have any precise method of course if you've got asymptotic flatness and there's techniques like that one can be see I was just briefly mentioned I think when people are confronted with a situation like this they usually of translation operators, which imply that's where it goes, and those don't have much to do with your allowable lunch, and to try and bring those, I don't think any of you can do it. That's not a satisfactory way to go, but I think the point I think is that it's as you are setting up what looks like a real conceptual problem, but you're doing so in a way which only applies in general relativity, precisely where the canonical methods are, as it were, undercutting this framework of the Schrodinger equation of the time-actually vector field. So one is worried that, one isn't clear actually I mean, it's a question of what one expects. If you're happy with quantum mechanics, from some perspective, maybe, maybe, or something, then you're worried. I mean, if you're talking about me, you do this and this and this. I really want to set that to one side. I, myself, don't see the problems with many ones that you do, but I'm really trying to look at your proposal on its own and look here's the source of the beauty of one that's here one would indeed have this conceptual problem that we're talking about if one had the familiar framework Schrodinger equation, an explicit time which would require a killing vector field one would indeed have the conceptual problem that we're only using what precisely solves that conceptual problem is that common gravity being the kind of restraining system that it is doesn't have a time-evolution in which we do in sentence. I think, Travis, none of these things really make it work. I mean, we can talk about a loop-bearer approach, but there are,

1:55:00 I mean, it has many high fictions, and it certainly comes to terms with general covariance better than the other approaches with, and that's true. But on the other hand, it still has, you can't deal with dynamics. You know, a constraint for it to sort it out with evolution. and there are some technical points you might say the technical points I certainly wouldn't agree with my theory on where it exists either it's or what you can always find a special case when a very specialized situation where space time is symmetric in space and then you can construct a quantitative gravity for that sector that could be done In general, a full-place theory doesn't exist. I think that's the view of the problem. I think we may strongly disagree with you, but I'm not really in a position to like to just take part of it. But usually these approaches do, when you have a talent transaction operator, they basically are very nothing to do. Oh, sure. It seems to me that it doesn't really address the issues in terms of the argument. I mean, I've talked about these things to people, you know, women's who are the form of gravity experts, you see, and all they go away running, probably, you see, they don't seem to have particular objections to this about it, you see. They may not like it. Well, I suspect it's because they are not happy with a certain point of time. but my point is that perhaps I've really been interested to marry a parent but my point is that the worry that you've got parents in a distance is to meet and that you know there can be that you've got to come from the parents and that you've got to be able to that very element is what seems to be absolutely important you see the way and actually bring them back it's like when you see playing a way as a parent it seems that everything about the marriage of one of the parents is forcing one without a traditional concept of time, you can issue it. So you just have to insist that we mustn't get it into a place of it. And the term problem is accepted as a fundamental problem. Many of us are very happy with Revelle's analysis about that. But with all the other analysis, there were Karl Revelle's analysis about it. Karl Revelle? Yeah, it's a, I don't think it's a problem on the table here.

1:57:30 One of the reasons I've suggested we start because one can philosophise but at least here's something one can go and see does it do, actually, or not. Oh, absolutely. We have a bit of a cue. So, Claire Hawkins and then I was just wondering about why some probabilities when they come into your objective class. You're quite right, I haven't actually, I mean, it's a bit sloppy what I do here in a sense that I'm not, but I'm tentatively assuming that the amplitude is more as equal. Now, it's not clear what role they're playing, because the actual calculation that I'm doing is on the D90T operation, really. But maybe that should be weighted by the amplitude. So you have one W's end of the coefficients, and there's a W squared plus Z squared contribution. I agree, that's something that should be looked at, and I've not. I'm just taking a simple situation, let's suppose the amplitudes are roughly equal so that I'm not addressing that. It may be that this formula will be modified, that when the amplitudes are significantly different from each other, the time scale of it will also be effective. And one needs to look at the general coherence of the scheme as a whole. So you have three lumps, so you position three locations and you do a pair of wipes and things like that. They probably are consistently conditioned by the whole thing. And that is the effect of the amplitude. And I love that effect. Thank you for making it. I think it's something which needs to be looked at. I've been very sloppy here and said, well, let's suppose it doesn't. as long as the amplitude is not the same, it's not meant to be an important factor. That's, that's not it. Jeeva Anandam has a, Jeeva Anandam has slight generalization and he's got different amplitude and different properties.

2:00:00 Yes, we recall that. What's that? Well, it's actually in your fashion. And he's got a generalization of your scheme, where he uses the ways that are already and uses okay well thank you I'm quite prepared to believe but it needs it needs some more general principles the whole thing needs to have some kind of consistency you need something like you break it down But I haven't practically ever seen how we had to do it. I'm wondering what's the precise reasoning behind choosing a lot of style of crystal It is for its social rigidity, as it were. Yes, it is. And you don't want to excite any part of the energy to go on. And that would be a good way to excite you very quickly. No, not much. It just makes a little complicated. I'm wondering, from my memory, though, what style of the text is that these words and what can be happened. I'm wondering, this way there's a scale, probably, there's a small representation of the cratons. I mean, in a sense, it must be some approximation of that. I do particularly think that there's still something in such a way of excellent solution. I'm just wondering whether there's a very small impact of a proton actually might be on a kind of scale in to what it's in such a way of doing. Oh, you're right. I don't think you've got that. I'm happy to see whether I'm just a human. I think I've already had a good idea. What about the impact is too huge, I think it's one of the things that we know it's been a few years of responding in a few years. But in this case, it's a very milder that one has been about to close to this case. So you're certainly right that there will be contributions to those modes of operation. And we have the last few years, they were actually doing the same thing. I'm sure I can't tell you.

2:02:30 Thank you. Thank you. Good to see you. Thanks. Thank you.

2:05:00 Oh, yes. There is a paper in the Journal of Applied Algebra from about, oh, it was quite a long time ago, it was around 1990 or 1991, which I'll look at because I've got, I've been You might be interested in that. It was a construction projectile, which is generally, obviously, a kind of long time. It kept, it kept, it kept, it kept up even close. Anyway, I'm just going to remind myself in detail that construction was looking at it. It was motivating very, very much by looking at it. and that we're not able to really say that this is a true thought, that came out as a hypothesis, not a logical approach. So there's a much, much more, if you like, how to do that constructual concept. As I do it, I also don't think I can do that. So I just want, for me, it's basically the work that I can do in that. Well, it's very interesting. I have to bring those things along, but I'm fascinated by it. I always thought, you know, what he would talk about, you know, different approaches to, as it were, taking their direction, their information in, you know, spaces and structures and challenges. You shouldn't do a little bit more, I don't ask if you have a philosophy. Oh, sure, which is that. It is my philosophy. I don't think there is a point. I don't think I have to agree. You know these guys that are some of the friends of China who are more than 12 groups in the open groups tomorrow. Tell me. There's nothing to do with some of the paracetists. No, no, no, no, no, no. No, I found a book. It's pretty crazy. And then they took a floor with it. Somebody told me that there was a piece of business

2:07:30 that it's a good job doing like one of them. It's a good job. I must look that up. What's the thing to look for? Just local tourism? Can you go about anything on that? I don't know. It's kind of jiveless from the discussion. Well, if you've got a base... I mean, stop them now, is it? Well, of course, as I know, I've kept computing that. I thought I was waiting for the insurance when he comes to a 5-5-12-0, that's a crime. As a matter of fact, I think that's the cost. Jeremy is another person who's got the problem. Unfortunately, the problem is he's actually got from sitting in that over at the end of the time. You probably won't hang around with us. I've got a dress straight back alone, unfortunately. That wasn't interesting. Um, I'm trying to find a place like, you know, to a valley, you know, a small group of rabbits on the land, you know, there's a lot of things that come from the open system here and things there on the road. Yeah, yeah, yeah. They're thinking, you know, like, small, you see the things that are all beautifully come together. 3, 3, 4, and then they have all these hand-weighted arguments. They're very short. They're all going to come together by 2000. I haven't read the book. I hate to say it, but I think it's going to be rather like a permanent 50-year time around. They'll still be saying in 2004, but in another 10 years. I've got two, I've got, I've got, I've got two in, would you believe, Bob Croft, yeah, he's in exactly the same position, he's got a whole lot of stuff, he's also not just Oh, right, yeah. You've probably got them all in there. Yes, I... I have actually taken a print of that. Right, right. What I've given you is only the quantum gravities. Don't worry. Not the top-off papers. No, those were the ones over...

2:10:00 Okay, I'm coming to Michael Green. I'm coming to Michael Green. I like to do the last round. Thank you. No, I did get it, I did get it, thank you very much indeed. It did, but it's finally all gone there. And as I told you, I've had a film on the cloud, that you didn't try on the phone, but I had my kids get quite a while. On Tuesday when I was... Well, it might not happen. I was back there on Tuesday looking for crypto. I stayed behind, I'd had a long evening with Crom Mager, when I got back I found I had a break and I knew much. But unfortunately, like a wooden shoe, I had kept all my backups in a couple from the same room, and everything. So, all my backups, every time I was with anybody's sentence for the last 18 months. So I'm not driving Jeremy and bought a couple of those people's dad, so it couldn't be exactly copies of everything. Thank you. Thank you.

2:12:30 Thank you. And as I said, I know it's not the case. Thank you. Thank you. Thank you.

2:15:00 Oh, my God. Thank you. Yeah. Thank you.

2:17:30 Thank you. Thank you. We'll be right back. Hello, can I have a point of Pock Northen, please? I'll look at it. I will. I will. Thank you.