Quantum and the unknowable universe | FULL DEBATE | Roger Penrose, Sabine Hossenfelder, Slavoj Žižek
Debate · The Institute of Art and Ideas ·
2025-04-19 · 0:45:43 · 6,720 words
with Roger Penrose, Announcer, Sabine Hossenfelder, Cathy Newman
science-physicsideologysubjectivityphilosophy-general
Žižek engages in a philosophical dialogue on quantum mechanics, arguing that its core insight is the ontological incompleteness of reality rather than epistemological limitation. He critiques the 'aestheticization' of physics, rejects the idea of a pre-existing higher harmony (Einstein), and posits that consciousness arises from the 'malfunctioning' or inconsistency of material processes. He concludes by analyzing the 'Tom and Jerry' cartoon to illustrate the retroactive constitution of reality via the 'Big Other'.
every located moment in this recording, click one to read it
The ideas in it 7
in the order they first come up; click a row for what he does with the idea here
The ontological status of reality is not fully constituted; gaps and potentialities are intrinsic to reality itself, not just our knowledge of it.
Physical theories (e.g., Penrose) proposing that wave function collapse occurs automatically after a certain time or mass threshold, independent of observation.
as “consciousness is rooted in malfunctioning”
Consciousness does not stem from a perfect, calculable system, but emerges from the inconsistency, disparity, and 'deadlock' of material processes.
The tendency to interpret quantum mechanics through the lens of beauty, simplicity, and harmony (associated with Einstein), which Žižek rejects as a mythological residue.
Because it includes the observer within reality (we are 'in' reality, not outside it), unlike idealist philosophies that posit an external, objective standpoint.
A metaphorical or literal interpretation of retrocausality in quantum mechanics, where a particle seemingly takes energy from the future to exist in the present.
The symbolic order or the field of ordinary reality that 'notices' or validates existence, retroactively constituting the subject's position.
Stories he reaches for 4
The cartoon cat walks off a cliff and doesn't fall until he looks down and realizes there is nothing there; this illustrates how the 'Big Other' (reality) retroactively validates existence.
“you remember, i always use my a cat. gets close to the precipice then it goes on walking... only when the cat looks down... it falls down”
One does not consciously 'choose' to fall in love; rather, one suddenly realizes they are already in love, illustrating that key decisions are non-calculable and retroactive.
“you never fall in love... all of a sudden you become aware that you already are in love”
French cuisine (cheese, champagne) emerged from 'malfunctioning' or carelessness (bad smell/fermentation) that was refined into an exquisite product, illustrating how higher forms emerge from material deadlock.
“they were doing cheese and they were doing it carelessly and the cheese started to smell bad”
In a video game, background objects (like a tree) are not fully programmed because they are not accessible; this illustrates how quantum reality has gaps and is an 'unfinished project' itself.
“when you are in a video game... you have a tree in the background... it's not fully programmed”
Works invoked 2
Lenin's work; Žižek uses it to illustrate the idealist error of excluding the observer from reality.
Helgoland book
Carlo Rovelli's book; Žižek agrees with its multiverse/no-collapse interpretation.
People invoked 8
A participant in the talk; Žižek states his problem is the same but in the opposite direction.
Carlo Rovelli positive
Agrees with Rovelli's 'Helgoland' theory that there is no collapse and that interaction constitutes observation.
Vladimir Lenin negative
Calls him 'the worst idealist' in 'Materialism and Empirio-criticism' for positing objective laws from an external, non-included position.
Roger Penrose negative
Disagrees with Penrose's 'objective theories of collapse' (that particles have self-awareness/free will).
Sabine Hossenfelder positive
Respects her critique of the 'aestheticization' of physics and her opposition to the idea that physics must be beautiful/simple.
Federico Faggin negative
Likely Giulio Chiribella or similar? No, likely 'Faggin' is a mis-transcription of a physicist proposing particles have free will. Žižek rejects this 'crazy theory'.
Niels Bohr positive
Cites Bohr's retort 'Don't tell God what to do' as the correct response to Einstein's theological projection.
Albert Einstein negative
Critiques Einstein's 'God does not play dice' as a religious belief in a higher harmony; calls him a 'religious guy' despite denying a personal god.
Transcript 56 turns
Roger Penrose
at that moment, as soon as that person looks at the screen, that great mass of all different superpositions suddenly becomes one with. makes no sense to me whatsoever.
at that moment, as soon as that person looks at the screen, that great mass of all different superpositions suddenly becomes one with. makes no sense to me whatsoever.
Announcer
welcome everybody to quantum in the unknowable universe. please give a warm round of applause for your host, Ganesh Taylor.
welcome everybody to quantum in the unknowable universe. please give a warm round of applause for your host, Ganesh Taylor.
Sabine Hossenfelder
thank you. the more quantum theory develops, the sillier it looks, wrote einstein in a letter in the 1920s. since then, quantum physics has been verified by experiment and has been central to many of the scientific and technological advances of the last century. but the problem that troubled einstein remains. quantum mechanics renders the universe fundamentally unknowable. heisenberg's uncertainty principle means that science is in principle unable to predict behaviour. he concluded elementary particles are not real. they form a world of potentialities or possibilities rather than one of things or facts. should we accept that quantum mechanics has made the universe unknowable? and if so, how should we proceed in the way the world depends on our observations? is science at play in a world of competing models, none of which can ultimately describe the universe? or is einstein's hunch right and we can uncover a theory that eliminates uncertainty and enables the correct description of the universe independent of any observer? to help us tackle these questions, we're joined today by three fantastic panellists. to my immediate right, sabine hossenfelder, sabine, i should say, hossenfelder, is an external member of the munich center for mathematical philosophy who specialises in the foundations of physics, and she's also one of the world's leading science communicators. on the screen, we're also joined by slavoj žižek, who is of course one of the most famous philosophers in the world, the author of more than 50 books, including most recently christian atheism, how to be a real materialist, and his new collection of essays against progress will be out in october. to my immediate left, we're joined by roger penrose. who is one of the world's leading mathematical physicists, and he won the nobel prize in 2020 for his groundbreaking discovery that black hole formation is a robust prediction of the general theory of relativity. so this conversation starts with the following question. should we accept that quantum mechanics has made the universe unknowable? sabina, i'd like to ask you to start us, please, three minutes on that.
thank you. the more quantum theory develops, the sillier it looks, wrote einstein in a letter in the 1920s. since then, quantum physics has been verified by experiment and has been central to many of the scientific and technological advances of the last century. but the problem that troubled einstein remains. quantum mechanics renders the universe fundamentally unknowable. heisenberg's uncertainty principle means that science is in principle unable to predict behaviour. he concluded elementary particles are not real. they form a world of potentialities or possibilities rather than one of things or facts. should we accept that quantum mechanics has made the universe unknowable? and if so, how should we proceed in the way the world depends on our observations? is science at play in a world of competing models, none of which can ultimately describe the universe? or is einstein's hunch right and we can uncover a theory that eliminates uncertainty and enables the correct description of the universe independent of any observer? to help us tackle these questions, we're joined today by three fantastic panellists. to my immediate right, sabine hossenfelder, sabine, i should say, hossenfelder, is an external member of the munich center for mathematical philosophy who specialises in the foundations of physics, and she's also one of the world's leading science communicators. on the screen, we're also joined by slavoj žižek, who is of course one of the most famous philosophers in the world, the author of more than 50 books, including most recently christian atheism, how to be a real materialist, and his new collection of essays against progress will be out in october. to my immediate left, we're joined by roger penrose. who is one of the world's leading mathematical physicists, and he won the nobel prize in 2020 for his groundbreaking discovery that black hole formation is a robust prediction of the general theory of relativity. so this conversation starts with the following question. should we accept that quantum mechanics has made the universe unknowable? sabina, i'd like to ask you to start us, please, three minutes on that.
Cathy Newman
thank you. well, my answer to this question is no, we should not accept it. i think there's been far too much acceptance of this quantum weirdness. i hear this all the time and i see it in the headlines, popular science headlines. there's something strange, something weird. i see this all the time and i'm very much with philip ball, who wrote a book called beyond weird, saying we need to go beyond weird in quantum mechanics, we need to understand it better. but i want to go a step further and say we also need to go beyond words. we need to actually find a mathematical problem, not just saying, well, something is strange and i don't like that kind of thing and i would like this to work a little bit better, but we actually need to figure out exactly what the problem is because only then can we solve it. and i'm of the opinion that the measurement problem in quantum mechanics is a real mathematical problem that requires a solution of which there aren't many candidate solutions. actually, roger penrose is one of the few that exists and i wish there were more and we should be paying more attention to experimental tests of these. ideas. and
thank you. well, my answer to this question is no, we should not accept it. i think there's been far too much acceptance of this quantum weirdness. i hear this all the time and i see it in the headlines, popular science headlines. there's something strange, something weird. i see this all the time and i'm very much with philip ball, who wrote a book called beyond weird, saying we need to go beyond weird in quantum mechanics, we need to understand it better. but i want to go a step further and say we also need to go beyond words. we need to actually find a mathematical problem, not just saying, well, something is strange and i don't like that kind of thing and i would like this to work a little bit better, but we actually need to figure out exactly what the problem is because only then can we solve it. and i'm of the opinion that the measurement problem in quantum mechanics is a real mathematical problem that requires a solution of which there aren't many candidate solutions. actually, roger penrose is one of the few that exists and i wish there were more and we should be paying more attention to experimental tests of these. ideas. and
Sabine Hossenfelder
take. slavoy, what do you think? do you think we should accept that quantum mechanics has made the universe unknowable?
take. slavoy, what do you think? do you think we should accept that quantum mechanics has made the universe unknowable?
Slavoj Žižek
i'm immensely proud to be here and i look at both of you as authorities. what surprises me. is usually we economists are the ones who engage in crazy speculations but from what i read just take the problem of the so-called big bang. there are those who claim there is a big bang, there are those who claim there was no big bang, there are those who claim there are repeated big bang. i cannot judge about it. so my solution to this. a very weird. sorry to use this term. one, eat. no, it doesn't make the universe unknowable. but it... that's what attracted me from when i was in high school about quantum mechanics. what appears to us as our epistemological limitation. unknowable, we cannot know it. it transposes this openness into reality itself. may i just finish with explaining this with a stupid metaphor that i is not precise, but i found it in a book. when you are in a video game. reality is not immersed in a video game. reality is not fully constituted. you have a tree in the background, but since it's not within the rules of the game that you can approach that tree, of course you and the tree is not fully programmed, all the details. and i think that the way i read it. quantum mechanics. the basic insight is that it moves in the same direction. reality itself. it.. constit. there are gaps in it. reality is an unfinished project in itself. so i agree totally. there are many things to be discovered and so on and so on. but... my answer would have been that. uncertainty. what is uncertainty is, again, part of reality itself. when we talk about wave functions as potentialities and so on. why shouldn't these potentialities include? ex in the sense of some reality, but not our ordinary notion of reality. i'm much more open here. i think that, for example, when einstein said dismissed the quantum effects, the spooky x at a distance, well, maybe this could radically change our notion of space. i think that quantum physics does compel us to rethink the very basic notions of our everyday reality. but again, my idea is this one. imagine god as a programmer. which is not i'm an a daily. isn't it that the lesson of quantum physics is that in some sense, one completely pleased head. and the were story for the vulgarity soft god which he pants down in the sense that god humans will never go deeper than atom. we went there and we caught god. so the problem is without god. can we think, is it possible to think reality as in itself ontologically simply incomplete, not fully? bro.
i'm immensely proud to be here and i look at both of you as authorities. what surprises me. is usually we economists are the ones who engage in crazy speculations but from what i read just take the problem of the so-called big bang. there are those who claim there is a big bang, there are those who claim there was no big bang, there are those who claim there are repeated big bang. i cannot judge about it. so my solution to this. a very weird. sorry to use this term. one, eat. no, it doesn't make the universe unknowable. but it... that's what attracted me from when i was in high school about quantum mechanics. what appears to us as our epistemological limitation. unknowable, we cannot know it. it transposes this openness into reality itself. may i just finish with explaining this with a stupid metaphor that i is not precise, but i found it in a book. when you are in a video game. reality is not immersed in a video game. reality is not fully constituted. you have a tree in the background, but since it's not within the rules of the game that you can approach that tree, of course you and the tree is not fully programmed, all the details. and i think that the way i read it. quantum mechanics. the basic insight is that it moves in the same direction. reality itself. it.. constit. there are gaps in it. reality is an unfinished project in itself. so i agree totally. there are many things to be discovered and so on and so on. but... my answer would have been that. uncertainty. what is uncertainty is, again, part of reality itself. when we talk about wave functions as potentialities and so on. why shouldn't these potentialities include? ex in the sense of some reality, but not our ordinary notion of reality. i'm much more open here. i think that, for example, when einstein said dismissed the quantum effects, the spooky x at a distance, well, maybe this could radically change our notion of space. i think that quantum physics does compel us to rethink the very basic notions of our everyday reality. but again, my idea is this one. imagine god as a programmer. which is not i'm an a daily. isn't it that the lesson of quantum physics is that in some sense, one completely pleased head. and the were story for the vulgarity soft god which he pants down in the sense that god humans will never go deeper than atom. we went there and we caught god. so the problem is without god. can we think, is it possible to think reality as in itself ontologically simply incomplete, not fully? bro.
Sabine Hossenfelder
fascinating thank you for that, slavoy. um... roger what are you thinking about quantum mechanics and making the universe unknowable? i feel you should have an opinion on this too.
fascinating thank you for that, slavoy. um... roger what are you thinking about quantum mechanics and making the universe unknowable? i feel you should have an opinion on this too.
Roger Penrose
but i think there's one thing i agree with the other speakers about, that it's wrong to say it's unknowable.
but i think there's one thing i agree with the other speakers about, that it's wrong to say it's unknowable.
Sabine Hossenfelder
fantastic. good.
fantastic. good.
Roger Penrose
on that side too. yes. it doesn't mean that it's deterministic, which is a completely different question. but one problem about quantum mechanics, i think that people think in the following way. they think that quantum mechanics as really about small things, like atoms and molecules and things like that. and big things are made out of small things, so therefore the laws apply equally to the big things.
on that side too. yes. it doesn't mean that it's deterministic, which is a completely different question. but one problem about quantum mechanics, i think that people think in the following way. they think that quantum mechanics as really about small things, like atoms and molecules and things like that. and big things are made out of small things, so therefore the laws apply equally to the big things.
Cathy Newman
right.
right.
Roger Penrose
and this is puzzling because for an atom it could be here and it could be here, or it could be here and here at the same time. and you have to consider quantum mechanics works in that way. there's this thing called the superposition principle, which says that there's one thing can happen and if there's another thing can happen, then you have superpositions where both happen at the same time. now i put forward an argument quite a long time ago actually, several arguments, but only one which i think i really trust, which asserts that the quantum state these superpositions like that will persist only for a certain length of time. and this is to do with trying to bring together the two basic principles of quantum mechanics and general relativity. quantum mechanics, it's the superposition principle, which i just referred to. general relativity is the principle of equivalence. that really goes back to galileo. he made a clear comment. i think the one i like the best is talking about fireworks and the fireworks come out and they make this beautiful spherical pattern and as this spherical pattern of sparks fall to the ground, it remains a sphere. it doesn't get flattened or stretched or something like that. it's as though the particles don't notice gravity. and this is well known now, you astronauts they can be in the and and they look down, there's the earth. they're not that far up that the earth's effects disappear. they effectively disappear because they're falling freely. and the principle of equivalence says that you can locally get rid of gravity by falling freely. and it turns out that these two principles, the principle of equivalence and the principle of superposition, are not quite consistent with each other. so i did a little calculation at one point to show that you can fix this by saying that the superpositions have a lifetime. so the thing can be here and here at the same time, but only for a lifetime which you can calculate. and if it's for something like that glass, for instance, it would be ridiculously tiny. in fact, the lifetime, i can tell you how you calculate it. you take that glass and you imagine two instances of a glass on top of each other, pull one away from the other and ask how much energy that would cost you considering only gravity. sure, nuclear forces, electric forces, that would be huge. but forget all those. it's only the gravitational effect. and the amount of energy that pulls you apart is the critical thing. and it's basically the reciprocal of that energy which gives you the lifetime in standard quantum mechanical units, which gives you the lifetime of the system. for that glass, it would be an instant. for a... a flea's eye, people call about that. this thing called the planck mass is about the mass of a flea's eye. even that, if you put that in a superposition it would a tiny fraction of a second. it would be one 30th, i forget what the number is.
and this is puzzling because for an atom it could be here and it could be here, or it could be here and here at the same time. and you have to consider quantum mechanics works in that way. there's this thing called the superposition principle, which says that there's one thing can happen and if there's another thing can happen, then you have superpositions where both happen at the same time. now i put forward an argument quite a long time ago actually, several arguments, but only one which i think i really trust, which asserts that the quantum state these superpositions like that will persist only for a certain length of time. and this is to do with trying to bring together the two basic principles of quantum mechanics and general relativity. quantum mechanics, it's the superposition principle, which i just referred to. general relativity is the principle of equivalence. that really goes back to galileo. he made a clear comment. i think the one i like the best is talking about fireworks and the fireworks come out and they make this beautiful spherical pattern and as this spherical pattern of sparks fall to the ground, it remains a sphere. it doesn't get flattened or stretched or something like that. it's as though the particles don't notice gravity. and this is well known now, you astronauts they can be in the and and they look down, there's the earth. they're not that far up that the earth's effects disappear. they effectively disappear because they're falling freely. and the principle of equivalence says that you can locally get rid of gravity by falling freely. and it turns out that these two principles, the principle of equivalence and the principle of superposition, are not quite consistent with each other. so i did a little calculation at one point to show that you can fix this by saying that the superpositions have a lifetime. so the thing can be here and here at the same time, but only for a lifetime which you can calculate. and if it's for something like that glass, for instance, it would be ridiculously tiny. in fact, the lifetime, i can tell you how you calculate it. you take that glass and you imagine two instances of a glass on top of each other, pull one away from the other and ask how much energy that would cost you considering only gravity. sure, nuclear forces, electric forces, that would be huge. but forget all those. it's only the gravitational effect. and the amount of energy that pulls you apart is the critical thing. and it's basically the reciprocal of that energy which gives you the lifetime in standard quantum mechanical units, which gives you the lifetime of the system. for that glass, it would be an instant. for a... a flea's eye, people call about that. this thing called the planck mass is about the mass of a flea's eye. even that, if you put that in a superposition it would a tiny fraction of a second. it would be one 30th, i forget what the number is.
Sabine Hossenfelder
it's okay, you don't have.
it's okay, you don't have.
Roger Penrose
remember with thirty digits, i think.
remember with thirty digits, i think.
Sabine Hossenfelder
you'll be forgiven for not knowing that off the top of your head. okay. i'm now thinking about fleas's eyes, to be honest. okay, so you don't think so either. the next question we were going to address was, does the world depend on our observations of it?
you'll be forgiven for not knowing that off the top of your head. okay. i'm now thinking about fleas's eyes, to be honest. okay, so you don't think so either. the next question we were going to address was, does the world depend on our observations of it?
Roger Penrose
oh, i see. no. it's nothing to do with people looking at it. you see observation there a red herring in my view. i mean many people thought well, maybe the thing which reduces the state. you see if you just followed, let's say, following the schroddinger equation, which tells you if you know what the state is now, quantum state, and that's a well-defined thing, if you know what the state is now, then it tells you what the state is tomorrow10 minutes or 100 years from now. the trouble is it doesn't. and it doesn't follow the schrodinger equation because at some point, what's called the collapse of the wave function takes place. now people tend to think that's... ridiculous. i mean, what does it mean by the collapse of the wave function? so they tend to think it's the observer coming along and looking at it. and this is the fault largely of the terminology used. that is sort of an observation.
oh, i see. no. it's nothing to do with people looking at it. you see observation there a red herring in my view. i mean many people thought well, maybe the thing which reduces the state. you see if you just followed, let's say, following the schroddinger equation, which tells you if you know what the state is now, quantum state, and that's a well-defined thing, if you know what the state is now, then it tells you what the state is tomorrow10 minutes or 100 years from now. the trouble is it doesn't. and it doesn't follow the schrodinger equation because at some point, what's called the collapse of the wave function takes place. now people tend to think that's... ridiculous. i mean, what does it mean by the collapse of the wave function? so they tend to think it's the observer coming along and looking at it. and this is the fault largely of the terminology used. that is sort of an observation.
Sabine Hossenfelder
right.
right.
Roger Penrose
and making an observation is supposed to collapse the wave function, because only then does somebody actually see it. but in my view, that's not the right way of looking at it. somebody's seeing it or not, is completely irrelevant. it's the fact that a big mass has moved, and then there is a lifetime, which means that this superposition has a well-defined lifetime, and it has nothing to do with anybody looks at it and not.
and making an observation is supposed to collapse the wave function, because only then does somebody actually see it. but in my view, that's not the right way of looking at it. somebody's seeing it or not, is completely irrelevant. it's the fact that a big mass has moved, and then there is a lifetime, which means that this superposition has a well-defined lifetime, and it has nothing to do with anybody looks at it and not.
Sabine Hossenfelder
that's interesting. i mean, i'm no physicist, sabrina, but there's that famous double slit experiment and various other things that show that you know, if there's an observer, the way a particle behaves is different, right? that's at least how... in principle, we're taught about these things and roger's saying he doesn't buy that one bit. he thinks it's sort of intrinsic to the sort of mass of the object being moved. what are your thoughts?
that's interesting. i mean, i'm no physicist, sabrina, but there's that famous double slit experiment and various other things that show that you know, if there's an observer, the way a particle behaves is different, right? that's at least how... in principle, we're taught about these things and roger's saying he doesn't buy that one bit. he thinks it's sort of intrinsic to the sort of mass of the object being moved. what are your thoughts?
Cathy Newman
well, so strictly speaking, i guess i would have to disagree with an overpr winner, which is always awkward. so i think that strictly speaking, whenever we observe something, we need to interact with it, so we affect it. there's no way around it. it's just that in many circumstances it doesn't play any role. like if i observe a boulder falling down or something, then yes, i have to interact with it because the light sc us off, but a boulder doesn't care. so we often neglect this. now, when it comes to quantum mechanics, this role of the observer is often conflated with some conscious beings, like someone who actually does the observing. but in the mathematics that never appears, which i think is what roger is getting at. so we have something that we call a measurement, and that's just a mathematical process, and it's the collapse of the wave function it doesn't really make any sense. and i entirely agree that we need to understand this better and it's probably got nothing to do do with the actual act of observation by a human being or even by a robot. it's rather it's something intrinsic to the system. could have something to do with gravity or it could be some entirely new process like there might be some new phenomenon playing in that needs to be parametrized or what have you. so i think that's probably what's going on. so yeah, so i think i agree and don't degree at the same time.
well, so strictly speaking, i guess i would have to disagree with an overpr winner, which is always awkward. so i think that strictly speaking, whenever we observe something, we need to interact with it, so we affect it. there's no way around it. it's just that in many circumstances it doesn't play any role. like if i observe a boulder falling down or something, then yes, i have to interact with it because the light sc us off, but a boulder doesn't care. so we often neglect this. now, when it comes to quantum mechanics, this role of the observer is often conflated with some conscious beings, like someone who actually does the observing. but in the mathematics that never appears, which i think is what roger is getting at. so we have something that we call a measurement, and that's just a mathematical process, and it's the collapse of the wave function it doesn't really make any sense. and i entirely agree that we need to understand this better and it's probably got nothing to do do with the actual act of observation by a human being or even by a robot. it's rather it's something intrinsic to the system. could have something to do with gravity or it could be some entirely new process like there might be some new phenomenon playing in that needs to be parametrized or what have you. so i think that's probably what's going on. so yeah, so i think i agree and don't degree at the same time.
Sabine Hossenfelder
fair enough. slavoy, perfect timing.
fair enough. slavoy, perfect timing.
Slavoj Žižek
my problem is the same as tabina, but maybe that's in the opposite direction. i agree and agree with the opposite opinion. my problem is this one. i'm speaking as the benevolent philosopher who tries to reach a little bit beyond this endless popular fake production. up what i. probably i use a wrong term, would have called objective theories of collapse. you put them either at rather at the level of time, which can be different for different objects, but simply after a certain amount of time. there is a collapse. there is another theory that i often found which is that space is is the fun that after you. after you get particles which are of a circle greatness amount automatically collapse happened then admit observation collapse and observation. here also, i am dressed as a benevolent observer. uh confuse. because i agree that this is the big problem for quantum physics. but again, we share. this how do you call it, multiverse theory that there is no collapse. endless univers. then uh you'll get i got this from carlo rovelli in helgoland. i think his theory is dead. whenever even just two tiny particles interact, in some sense one is already observing the other. and so on. on the other hand, we have, i hope i will pronounce his name correctly, faggin, for whom, and i'm a materialist, i don't buy this, but it's a crazy theory. for whom the collapse of superpositions means that even the tiniest part has not only some kind of self-awareness but even free will that this uncertainty means even the tiniest particles there. well, i don't agree of course with this and i also don't uh... at no. consciousness if for no other reasons than for the reason that in our even close experience but that's another topic me as that. somebody in try analysis. i think the key decisions that we make are never a concept that is a pathetic example that i often use. think about falling in love. you never fall in love. it's never now i look around oh i choose you, i fall in love. all of a sudden you become aware that you already are in love. the question rger i respect and agree with your big argument that consciousness is not. calcul your interpretation reference to g th and so on and so on. but again, nobody will probably like this solution, but you know what my, no science behind this. philosophical intuition. if that. yes, it. non calculable. but this doesn't necessarily mean that there must be some prior principle. some deeper mind which cannot be calculated. i am more and more convinced that the non-calculability which involves a certain inconsistency, disparity and so on is the thing that maybe gives birth to consciousness. consciousness is for me always rooted in something that i cannot but call a malfunctioning of a certain apparatus you know it's like. another of my back may be jokes. i think all new great things emerge from malfunctionings. for example, a french friend of mine gave me the best theory of french cuisine. that they were doing cheese and they were doing it carelessly and the cheese started to smell bad. and then they said, oh my god, why don't we make out of this a more exquisite product and so on. bad smelling french cheese or champagne something went wrong with why with some fermentation, they said, okay, you see what i mean? when things go wrong, i don't think we need a fire. d man. i believe that. the deadlock itself can generate the higher demand.
my problem is the same as tabina, but maybe that's in the opposite direction. i agree and agree with the opposite opinion. my problem is this one. i'm speaking as the benevolent philosopher who tries to reach a little bit beyond this endless popular fake production. up what i. probably i use a wrong term, would have called objective theories of collapse. you put them either at rather at the level of time, which can be different for different objects, but simply after a certain amount of time. there is a collapse. there is another theory that i often found which is that space is is the fun that after you. after you get particles which are of a circle greatness amount automatically collapse happened then admit observation collapse and observation. here also, i am dressed as a benevolent observer. uh confuse. because i agree that this is the big problem for quantum physics. but again, we share. this how do you call it, multiverse theory that there is no collapse. endless univers. then uh you'll get i got this from carlo rovelli in helgoland. i think his theory is dead. whenever even just two tiny particles interact, in some sense one is already observing the other. and so on. on the other hand, we have, i hope i will pronounce his name correctly, faggin, for whom, and i'm a materialist, i don't buy this, but it's a crazy theory. for whom the collapse of superpositions means that even the tiniest part has not only some kind of self-awareness but even free will that this uncertainty means even the tiniest particles there. well, i don't agree of course with this and i also don't uh... at no. consciousness if for no other reasons than for the reason that in our even close experience but that's another topic me as that. somebody in try analysis. i think the key decisions that we make are never a concept that is a pathetic example that i often use. think about falling in love. you never fall in love. it's never now i look around oh i choose you, i fall in love. all of a sudden you become aware that you already are in love. the question rger i respect and agree with your big argument that consciousness is not. calcul your interpretation reference to g th and so on and so on. but again, nobody will probably like this solution, but you know what my, no science behind this. philosophical intuition. if that. yes, it. non calculable. but this doesn't necessarily mean that there must be some prior principle. some deeper mind which cannot be calculated. i am more and more convinced that the non-calculability which involves a certain inconsistency, disparity and so on is the thing that maybe gives birth to consciousness. consciousness is for me always rooted in something that i cannot but call a malfunctioning of a certain apparatus you know it's like. another of my back may be jokes. i think all new great things emerge from malfunctionings. for example, a french friend of mine gave me the best theory of french cuisine. that they were doing cheese and they were doing it carelessly and the cheese started to smell bad. and then they said, oh my god, why don't we make out of this a more exquisite product and so on. bad smelling french cheese or champagne something went wrong with why with some fermentation, they said, okay, you see what i mean? when things go wrong, i don't think we need a fire. d man. i believe that. the deadlock itself can generate the higher demand.
Sabine Hossenfelder
fantastic. well, i think i've just realized i've fallen in love. but also, on a serious note, okay, so we're talking about whether or not there's a function for a conscious observer or not in our understanding of the world, right? what is the relative importance of interaction in this sort of understanding of the world? and the sort of next thing that we wanted to talk about actually was whether or not einstein was right that god does not play dice with the universe. and roger, you've sort of touched upon this already about this question of determinism essentially. and i think that that ties in with what slavoy has just been telling us about as well, this idea of consciousness and randomness and you know? do you think einstein was right about that, that god, if there is a god does not play dice with the universe.
fantastic. well, i think i've just realized i've fallen in love. but also, on a serious note, okay, so we're talking about whether or not there's a function for a conscious observer or not in our understanding of the world, right? what is the relative importance of interaction in this sort of understanding of the world? and the sort of next thing that we wanted to talk about actually was whether or not einstein was right that god does not play dice with the universe. and roger, you've sort of touched upon this already about this question of determinism essentially. and i think that that ties in with what slavoy has just been telling us about as well, this idea of consciousness and randomness and you know? do you think einstein was right about that, that god, if there is a god does not play dice with the universe.
Roger Penrose
that's a different question. you see. i'm trying to say that the collapse of the wave function, which is normally considered a random process, you just get a probability for it to doing, the particle is in a superposition of being here and here, and then it collapses to being either here or here, but with a certain probability. and then it might do this or it might do that, and that's all you can say. now i'm less happy with that. i'm not saying that it's not random. i don't mind if it is random i think i don't think it is exactly the answer that it's random. i think there's something much more subtle. and then you bring it in this issue of a conscious observer, which at this stage of the argument is a red herring. it's also a red herring which i like to play with, because i do consider this is an important question. but it's not a question that comes in at the level of whether the collapse takes place, when it takes place. i regard that as an objective process which has nothing to do with whether anybody looks at it. i'd like to consider a follow-up. yeah. if i can tell a little story, i imagine there is a planet out there somewhere a long way off, which is very much like the earth, just like the earth, except for some reason life never got started. now, consider the weather. the weather is supposed to be what's called a... chaotic process that it depends on little tiny effects. people often talk about the butterfly. its wings flap this way rather than that way and it makes eventually the other does that rather than this. now, on this planet, there aren't any butterflies, there's certainly no human beings, no nothing like that. so on this planet, according to that point of view, the weather would be a superposition of all possible weathers, a great mess.
that's a different question. you see. i'm trying to say that the collapse of the wave function, which is normally considered a random process, you just get a probability for it to doing, the particle is in a superposition of being here and here, and then it collapses to being either here or here, but with a certain probability. and then it might do this or it might do that, and that's all you can say. now i'm less happy with that. i'm not saying that it's not random. i don't mind if it is random i think i don't think it is exactly the answer that it's random. i think there's something much more subtle. and then you bring it in this issue of a conscious observer, which at this stage of the argument is a red herring. it's also a red herring which i like to play with, because i do consider this is an important question. but it's not a question that comes in at the level of whether the collapse takes place, when it takes place. i regard that as an objective process which has nothing to do with whether anybody looks at it. i'd like to consider a follow-up. yeah. if i can tell a little story, i imagine there is a planet out there somewhere a long way off, which is very much like the earth, just like the earth, except for some reason life never got started. now, consider the weather. the weather is supposed to be what's called a... chaotic process that it depends on little tiny effects. people often talk about the butterfly. its wings flap this way rather than that way and it makes eventually the other does that rather than this. now, on this planet, there aren't any butterflies, there's certainly no human beings, no nothing like that. so on this planet, according to that point of view, the weather would be a superposition of all possible weathers, a great mess.
Sabine Hossenfelder
h.
h.
Roger Penrose
now the space probe goes up, it's aimed at trying to take a photograph of this mess and propagate it back to earth. several light years away, takes a long time to get there, and then it takes a photograph of the planet with this mass of superpositions of all possible weathers. it comes back, and as it gets to the place where it's within communication distance from the earth, it sends a signal to the people on the earth, and somebody's looking at the computer screen. at that moment, as soon as that person looks at the screen, that great mass of all different superpositions suddenly becomes one weather. makes no sense to me whatsoever.
now the space probe goes up, it's aimed at trying to take a photograph of this mess and propagate it back to earth. several light years away, takes a long time to get there, and then it takes a photograph of the planet with this mass of superpositions of all possible weathers. it comes back, and as it gets to the place where it's within communication distance from the earth, it sends a signal to the people on the earth, and somebody's looking at the computer screen. at that moment, as soon as that person looks at the screen, that great mass of all different superpositions suddenly becomes one weather. makes no sense to me whatsoever.
Sabine Hossenfelder
right.
right.
Roger Penrose
it's already decided to be one way or another way before that happened. it's nothing to do with the conscious observer sitting in and looking at the television screen to decide which way it's gone. now, when i say it's nothing to do with it, that's not quite what i mean when we look at it the other way around. what is consciousness? that's another discussion altogether. we're not talking about that here i think. at least i don't know if we are. you see, i do take the view that the other way around is important too. that is to say, whatever the deep laws of physics are, they are, as they currently exist, computable. and i had an argument, i still think i believe it, a long time ago. which was when i went to a course. nothing to do with what i was actually doing on mathematical logic. and i learned about goerdels's theorem and i was extraordinarily impressed by it because what it said was, if you have a device which acts according to computable laws. then you have a statement which you may construct out of how the machine is made. and that statement is asserting its own falsity, basically like that. and the thing is that asserting that on the basis of these computable laws and you can see that what it's doing, it can't be a computable decision. that's the idea. so i formed a view. but conscious understanding, which is what enables you to understand why the goels theorem is true, if you like. on depends on knowing not the rules which the system is based on, but knowing why they worked, which means understanding why they are given truths. why do these rules which gave you truth from a previous truth and going to give you form. process which is a completely computational process, how do you know that the answer is true? and the godel statement tells you why it's true. and it's true not because it follows the rules, but because you know that the rules only give you truths. and that's the subtle difference. you know that following the rules only gives you a truth. and that tells you that this statement is truth by virtue of your knowing that the rules only give you truth. it's an amazing thing. you really have to see it to see why this works. but it tells you that your understanding transcends the following of the rules. so the question, what is understanding? well, it's something that seems to involve consciousness. because you can say, well, if an object understands something, it must at least be aware of it. it doesn't make any sense to say it understands it without being aware of it. that's just normal language. so i would say that normal language is probing something really important. it's got to be conscious to understand something. so i'm trying to say that the quality of understanding is not computable. and therefore it's something beyond what we understand in current physics. and the claim i'm making that what really goes on in the collapse of the wave function. but it's a completely different story and i shouldn't really have gone into it here.
it's already decided to be one way or another way before that happened. it's nothing to do with the conscious observer sitting in and looking at the television screen to decide which way it's gone. now, when i say it's nothing to do with it, that's not quite what i mean when we look at it the other way around. what is consciousness? that's another discussion altogether. we're not talking about that here i think. at least i don't know if we are. you see, i do take the view that the other way around is important too. that is to say, whatever the deep laws of physics are, they are, as they currently exist, computable. and i had an argument, i still think i believe it, a long time ago. which was when i went to a course. nothing to do with what i was actually doing on mathematical logic. and i learned about goerdels's theorem and i was extraordinarily impressed by it because what it said was, if you have a device which acts according to computable laws. then you have a statement which you may construct out of how the machine is made. and that statement is asserting its own falsity, basically like that. and the thing is that asserting that on the basis of these computable laws and you can see that what it's doing, it can't be a computable decision. that's the idea. so i formed a view. but conscious understanding, which is what enables you to understand why the goels theorem is true, if you like. on depends on knowing not the rules which the system is based on, but knowing why they worked, which means understanding why they are given truths. why do these rules which gave you truth from a previous truth and going to give you form. process which is a completely computational process, how do you know that the answer is true? and the godel statement tells you why it's true. and it's true not because it follows the rules, but because you know that the rules only give you truths. and that's the subtle difference. you know that following the rules only gives you a truth. and that tells you that this statement is truth by virtue of your knowing that the rules only give you truth. it's an amazing thing. you really have to see it to see why this works. but it tells you that your understanding transcends the following of the rules. so the question, what is understanding? well, it's something that seems to involve consciousness. because you can say, well, if an object understands something, it must at least be aware of it. it doesn't make any sense to say it understands it without being aware of it. that's just normal language. so i would say that normal language is probing something really important. it's got to be conscious to understand something. so i'm trying to say that the quality of understanding is not computable. and therefore it's something beyond what we understand in current physics. and the claim i'm making that what really goes on in the collapse of the wave function. but it's a completely different story and i shouldn't really have gone into it here.
Sabine Hossenfelder
slavoy, yes, please.
slavoy, yes, please.
Slavoj Žižek
i want to manipulate in a very nasty way and get sabine on my side against einstein, mainly. i, i enjoyed one of your last books where you explode against aestheticization of physical sciences. it must be a beautiful, simple formula and so on. until you brutally opposed. i deeply agree with you because i think that although einstein didn't believe in a personal god when he says god does not play dice. what he meant there are many quotes is precisely, for example, god. who revealed himself in the harmony of all that exists, the universe marvelously arranged and so on and so on. so if you say god doesn't play dice, my answer without involving god is, we all know, i hope, what ne. niels bohr's answer to this was, don't tell god what to do or what not to do to play. i think that einstein was here very clear, precisely along the lines outlined now by roger.. he's that, and i don't agree with him here. that. there is no science without religion. religion in the sense of trust in some higher natural order that waits there to be discovered and so on and so on. no, my idea is precisely that. universe it. such a myth that i wouldn't even use the term universe because it brings out at least for me, all those old mythological thinking which survives in you know universe is the big unity and then what is the base big unity is it fire, water and so on no universe is a and irreducible there are local necessities weak. emerged but always in a contingent way. so paradoxically i think that although einstein denied a personal god, he is for me still. and he said this. basically a religious guy because he believes in this higher harmony of the universe. and i think that if there is a lesson of quantum mechanics in all its versions is that no, we have to we have to drop this. in this sense, although quantum mechanics, and i hate those guys who do this, is often given some kind of a fake spiritual twist like, you know, all this instant communication between two particles prove that there is a higher spiritual connection outside time, space and so on. i claim that no, quantum mechanics is the only radical materialist theory. as you already said all of you, observation is not does not mean there is reality we are somewhere. the paradox of observation advocated by quantum mechanics is dead. but's slightly. we are in reality. we are a part of reality. we are not outside. which is why i will name now somebody whom i respect politically but not philosophically. for me, the worst idealist is lenin in his materialism and empirio-criticism, where he talks about objective laws, all of reality. yeah, but where does he stand? from what position? that's his duty. i think quantum mechanics is deeply materialist because it includes us into reality. sorry if i was killing long.
i want to manipulate in a very nasty way and get sabine on my side against einstein, mainly. i, i enjoyed one of your last books where you explode against aestheticization of physical sciences. it must be a beautiful, simple formula and so on. until you brutally opposed. i deeply agree with you because i think that although einstein didn't believe in a personal god when he says god does not play dice. what he meant there are many quotes is precisely, for example, god. who revealed himself in the harmony of all that exists, the universe marvelously arranged and so on and so on. so if you say god doesn't play dice, my answer without involving god is, we all know, i hope, what ne. niels bohr's answer to this was, don't tell god what to do or what not to do to play. i think that einstein was here very clear, precisely along the lines outlined now by roger.. he's that, and i don't agree with him here. that. there is no science without religion. religion in the sense of trust in some higher natural order that waits there to be discovered and so on and so on. no, my idea is precisely that. universe it. such a myth that i wouldn't even use the term universe because it brings out at least for me, all those old mythological thinking which survives in you know universe is the big unity and then what is the base big unity is it fire, water and so on no universe is a and irreducible there are local necessities weak. emerged but always in a contingent way. so paradoxically i think that although einstein denied a personal god, he is for me still. and he said this. basically a religious guy because he believes in this higher harmony of the universe. and i think that if there is a lesson of quantum mechanics in all its versions is that no, we have to we have to drop this. in this sense, although quantum mechanics, and i hate those guys who do this, is often given some kind of a fake spiritual twist like, you know, all this instant communication between two particles prove that there is a higher spiritual connection outside time, space and so on. i claim that no, quantum mechanics is the only radical materialist theory. as you already said all of you, observation is not does not mean there is reality we are somewhere. the paradox of observation advocated by quantum mechanics is dead. but's slightly. we are in reality. we are a part of reality. we are not outside. which is why i will name now somebody whom i respect politically but not philosophically. for me, the worst idealist is lenin in his materialism and empirio-criticism, where he talks about objective laws, all of reality. yeah, but where does he stand? from what position? that's his duty. i think quantum mechanics is deeply materialist because it includes us into reality. sorry if i was killing long.
Sabine Hossenfelder
oh i wasn't expecting to hear about lenin in this debate, but i'm glad he's joined the chat.
oh i wasn't expecting to hear about lenin in this debate, but i'm glad he's joined the chat.
Cathy Newman
so maybe i could say something for the sake of context because we've been talking about einstein's quote that god doesn't play dice. i think it's good to remember what he was actually referring to because i agree with roger that it's kind of the wrong question to ask, but he had a reason to ask this question. and einstein was thinking of a very simple experiment. so he was considering it as a thought experiment where you have a quantum particle which you send through a very small slit, so you know where it is basically, and it goes through, and the wave function of the particle spreads out into all directions. but when you observe the particle, it's only in one place. so that wave function suddenly has to focus. and so the moment that you measure the particle, say on the right side, the wave function on the other side has to know to disappear.. and it has to know that instantaneously faster than the speed of light. so this is what einstein called spooky action at a distance. and clearly he didn't like it because it was violating his theory of special relativity, according to which nothing can go faster than the speed of light. and so he said, actually, the particle needs to know where it's going already by the time it started traveling. and it's determined by some kind of hidden variable, that's what they were called. and that reintroduces determinism.
so maybe i could say something for the sake of context because we've been talking about einstein's quote that god doesn't play dice. i think it's good to remember what he was actually referring to because i agree with roger that it's kind of the wrong question to ask, but he had a reason to ask this question. and einstein was thinking of a very simple experiment. so he was considering it as a thought experiment where you have a quantum particle which you send through a very small slit, so you know where it is basically, and it goes through, and the wave function of the particle spreads out into all directions. but when you observe the particle, it's only in one place. so that wave function suddenly has to focus. and so the moment that you measure the particle, say on the right side, the wave function on the other side has to know to disappear.. and it has to know that instantaneously faster than the speed of light. so this is what einstein called spooky action at a distance. and clearly he didn't like it because it was violating his theory of special relativity, according to which nothing can go faster than the speed of light. and so he said, actually, the particle needs to know where it's going already by the time it started traveling. and it's determined by some kind of hidden variable, that's what they were called. and that reintroduces determinism.
Sabine Hossenfelder
h
h
Cathy Newman
and this is why he was talking about, you, the question, does god play dice? is the universe actually non-deterministic? it was because he wanted to reinstate a locality to make the theory compatible with relativity. and so i think that this question of determinism is kind of misleading because what he was trying to get at is really locality. that was very helpful.
and this is why he was talking about, you, the question, does god play dice? is the universe actually non-deterministic? it was because he wanted to reinstate a locality to make the theory compatible with relativity. and so i think that this question of determinism is kind of misleading because what he was trying to get at is really locality. that was very helpful.
Sabine Hossenfelder
s been.
s been.
Slavoj Žižek
just stop questioning with sabila because this interests me immensely. you used words which to me appear strong for this expression that you hate weird, but weird in the most provocative sense. you say particle must know particle knows from the beginning. why don't you simply say it's in the nature, in the objective structure of a particle to follow this path? why did you use the term knowledge?
just stop questioning with sabila because this interests me immensely. you used words which to me appear strong for this expression that you hate weird, but weird in the most provocative sense. you say particle must know particle knows from the beginning. why don't you simply say it's in the nature, in the objective structure of a particle to follow this path? why did you use the term knowledge?
Cathy Newman
well, that's just a word. as i said in the beginning, we need to go beyond words. so what i'm trying to do is i'm trying to... i'm trying to use english to explain equations that i have in mind and i agree with you that maybe saying it knows is not a good way to say it. i'm not trying to say that the particle has some kind of brain and it decides where to go. it's just some variable you can use to calculate what's going on.
well, that's just a word. as i said in the beginning, we need to go beyond words. so what i'm trying to do is i'm trying to... i'm trying to use english to explain equations that i have in mind and i agree with you that maybe saying it knows is not a good way to say it. i'm not trying to say that the particle has some kind of brain and it decides where to go. it's just some variable you can use to calculate what's going on.
Sabine Hossenfelder
does that relate to what you were saying, roger, about having a sort of sense that the sort of collapse of the wave function could be random but maybe is a little bit not random.
does that relate to what you were saying, roger, about having a sort of sense that the sort of collapse of the wave function could be random but maybe is a little bit not random.
Roger Penrose
i don't know whether i should go into this, but you see quite a subtle issue, particularly the thing about, you know, if it collapses, how does the part of the wave function over there know to collapse, etc etc. now the thing is, i probably shouldn't go into this, but let me do it anyway. i had a long time thinking about this really, before i thought about it, that in order to understand the timing, of collapse of the wave function and that sort of thing. it's a really subtle issue and one can really only understand it in the sense that you have to have what i recall two kinds of reality. there's what i call quantum reality and classical reality. in classical reality, you can... ascertain. i can say, hello glass, what's your shape? and it says, i've got a circle at the top and i'm pretty well parallel down there, etc etc. so it classical reality, you can ask a thing a question about it and it can answer. very directly. quantum reality, you can only confirm so it's a distinction. and was think l einstein actually, when we're talking about einstein here, is question how real is the wave function? and you can think about the simplest quantum system really is the spin of a spin half particle. and it can spin right-handed about the up direction or right-handed about the down direction. and you usually talk about the direction in which it's spinning. it really means right-handed about that direction. and the different directions, they're really two states, up and down, and then all the others are superpositions of those two. now can you ascertain i've got a free electron here, which is just on its own here. can you ascertain what its spin is, where its spin is pointing? no, you can't. but if you had somehow, in the way that was produced, some machinery and all that stuff, by now you say the electron would be spinning about that axis. and you can confirm that. you can do an experiment that says, hello, hello electron, is your spin about that axis? and 100% certainty, better's say, you can repeat the experiment many, many times, 100% certainty you'll get it right. so you can confirm it. if you didn't have it right, it would say yes sometimes, no other times. so the quantum state that can be confirmed, but it cannot be ascertained. and this is how you get around the various paradoxes that are involved in special relativity. can you send signals into the past and all that kind of stuff. it sounds pretty crazy when you look at it, but it doesn't lead to a contradiction. because it's quantum reality. and quantum reality you cannot ascertain. you can only confirm. and so that's the way you get round the problems. i can say what is real about the universe. we have to be careful. you mean quantum real or classical real? and it's not quite the same question. and most things we talk about are pretty big, and so we're talking about classical reality all the time. so that's a reasonable kind of thing to talk about. but when you're talk about quantum experiments and quantum systems, you're going to worry about it, especially when they're what's called entangled. you have two particles which doesn't individually have a state, but it's only related to another one.
i don't know whether i should go into this, but you see quite a subtle issue, particularly the thing about, you know, if it collapses, how does the part of the wave function over there know to collapse, etc etc. now the thing is, i probably shouldn't go into this, but let me do it anyway. i had a long time thinking about this really, before i thought about it, that in order to understand the timing, of collapse of the wave function and that sort of thing. it's a really subtle issue and one can really only understand it in the sense that you have to have what i recall two kinds of reality. there's what i call quantum reality and classical reality. in classical reality, you can... ascertain. i can say, hello glass, what's your shape? and it says, i've got a circle at the top and i'm pretty well parallel down there, etc etc. so it classical reality, you can ask a thing a question about it and it can answer. very directly. quantum reality, you can only confirm so it's a distinction. and was think l einstein actually, when we're talking about einstein here, is question how real is the wave function? and you can think about the simplest quantum system really is the spin of a spin half particle. and it can spin right-handed about the up direction or right-handed about the down direction. and you usually talk about the direction in which it's spinning. it really means right-handed about that direction. and the different directions, they're really two states, up and down, and then all the others are superpositions of those two. now can you ascertain i've got a free electron here, which is just on its own here. can you ascertain what its spin is, where its spin is pointing? no, you can't. but if you had somehow, in the way that was produced, some machinery and all that stuff, by now you say the electron would be spinning about that axis. and you can confirm that. you can do an experiment that says, hello, hello electron, is your spin about that axis? and 100% certainty, better's say, you can repeat the experiment many, many times, 100% certainty you'll get it right. so you can confirm it. if you didn't have it right, it would say yes sometimes, no other times. so the quantum state that can be confirmed, but it cannot be ascertained. and this is how you get around the various paradoxes that are involved in special relativity. can you send signals into the past and all that kind of stuff. it sounds pretty crazy when you look at it, but it doesn't lead to a contradiction. because it's quantum reality. and quantum reality you cannot ascertain. you can only confirm. and so that's the way you get round the problems. i can say what is real about the universe. we have to be careful. you mean quantum real or classical real? and it's not quite the same question. and most things we talk about are pretty big, and so we're talking about classical reality all the time. so that's a reasonable kind of thing to talk about. but when you're talk about quantum experiments and quantum systems, you're going to worry about it, especially when they're what's called entangled. you have two particles which doesn't individually have a state, but it's only related to another one.
Sabine Hossenfelder
i mean, you'll forgive me, i'm not a physicist, but aren't those two things related to each other? isn't that where the problem comes in? i mean, of course, the glass is a classical reality, but if quantum mechanics is real, then it is also... within
i mean, you'll forgive me, i'm not a physicist, but aren't those two things related to each other? isn't that where the problem comes in? i mean, of course, the glass is a classical reality, but if quantum mechanics is real, then it is also... within
Roger Penrose
but it's so big you see that the collapse has settled its state into pretty, i think the quantum reality and classical reality are pretty well the same.
but it's so big you see that the collapse has settled its state into pretty, i think the quantum reality and classical reality are pretty well the same.
Sabine Hossenfelder
so is it a matter of levels? effectively, you're saying that the quantum... quantum reality only exists in sort of one level. and it's not one that we really have much access to because all the things that we interact with are at a level that mean that the quantum rules no longer apply.
so is it a matter of levels? effectively, you're saying that the quantum... quantum reality only exists in sort of one level. and it's not one that we really have much access to because all the things that we interact with are at a level that mean that the quantum rules no longer apply.
Roger Penrose
i think that's roughly true, yes. only if you're doing a quantum experiment, you see, deliberately something quantum and you're trying to ask it a quantum answer.
i think that's roughly true, yes. only if you're doing a quantum experiment, you see, deliberately something quantum and you're trying to ask it a quantum answer.
Sabine Hossenfelder
me then the
me then the
Roger Penrose
then you have to worry about the quantum reality.
then you have to worry about the quantum reality.
Sabine Hossenfelder
would you agree with that, sabina?
would you agree with that, sabina?
Cathy Newman
rough roughly
rough roughly
Sabine Hossenfelder
yeah good job. okay, fantastic, everybody.... um...
yeah good job. okay, fantastic, everybody.... um...
Slavoj Žižek
that. a brief question for both.
that. a brief question for both.
Sabine Hossenfelder
yeah, please, slavoy, please.
yeah, please, slavoy, please.
Slavoj Žižek
i read, correct me if i'm wrong and it was bullshit what i read, but in one of the, i admit it, copenhagen's trend to quantum mechanics, i read of this what they call borrowing from the future. if a particle can do something. is the borrowing the energy to do it from the future and then when the moment of reckoning comes it already self- annihilihilates itself. it is as if we have an objective social order and you can move in a shady domain. before what in my psych were gone, i would have called the big other the order of our ordinary reality notices it it in sorry for again a popular metaphor. uh. you know my favorite thing in all those cartoons, tom and jerry was that you remember, i always use my a cat. gets close to the precipice then it goes on walking. and nothing happens. only when the cat looks down, oh my god, but there is nothing down, it falls down. according to some readings, doesn't something similar happen in death. thank you be. quantum. domain before this quantum domain had its effects but at another level.. deeply agree with this snow quantum reality is different from ordinary reality and i agree with if i got it correctly and brutally correct me if i'm wrong. that uh the key problem for me is the following one, that some physicists and even some, this may surprise you, tell the marxist leftists who. transposed on topic duality quantum reality ordinary reality this boring marks topic of of life process, creative life process and then it raises. and they claim ed quantum waves are the domain of physical freedom, everything is open, and then you have alienation, reification, and so on. no. the big problem for me, i don't have an answer. but for this to get an answer from any of you, i am, sorry for my vulgar metaphor, ready to sell my mother into slavery. it is. what? must go on already in quantum reality. that pushed it towards collapse. there must be. already there quantum reality is for me not some happy domain everything is possible and so on. no it must have a certain impossibility tension and so on. i'm speaking very naive terms and with all respect i am now turning to you.
i read, correct me if i'm wrong and it was bullshit what i read, but in one of the, i admit it, copenhagen's trend to quantum mechanics, i read of this what they call borrowing from the future. if a particle can do something. is the borrowing the energy to do it from the future and then when the moment of reckoning comes it already self- annihilihilates itself. it is as if we have an objective social order and you can move in a shady domain. before what in my psych were gone, i would have called the big other the order of our ordinary reality notices it it in sorry for again a popular metaphor. uh. you know my favorite thing in all those cartoons, tom and jerry was that you remember, i always use my a cat. gets close to the precipice then it goes on walking. and nothing happens. only when the cat looks down, oh my god, but there is nothing down, it falls down. according to some readings, doesn't something similar happen in death. thank you be. quantum. domain before this quantum domain had its effects but at another level.. deeply agree with this snow quantum reality is different from ordinary reality and i agree with if i got it correctly and brutally correct me if i'm wrong. that uh the key problem for me is the following one, that some physicists and even some, this may surprise you, tell the marxist leftists who. transposed on topic duality quantum reality ordinary reality this boring marks topic of of life process, creative life process and then it raises. and they claim ed quantum waves are the domain of physical freedom, everything is open, and then you have alienation, reification, and so on. no. the big problem for me, i don't have an answer. but for this to get an answer from any of you, i am, sorry for my vulgar metaphor, ready to sell my mother into slavery. it is. what? must go on already in quantum reality. that pushed it towards collapse. there must be. already there quantum reality is for me not some happy domain everything is possible and so on. no it must have a certain impossibility tension and so on. i'm speaking very naive terms and with all respect i am now turning to you.
Sabine Hossenfelder
slavoy, i think as abina can answer your questions.
slavoy, i think as abina can answer your questions.
Cathy Newman
well, i'm not...
well, i'm not...
Sabine Hossenfelder
please.
please.
Cathy Newman
i understood the question, but i can say something about this problem of borrowing energy from the future and stuff like this, because i was recently thinking about this, and i think this will make a nice closure, which is why i've come to agree with penrose that the collapse of the wave function got to have something to do with gravity. so forget everything about complicated quantum experiments, just imagine you send a single photon through a beam splitter. so beam splitters does what the word says, it splits a beam. so the wave function of the photon has a 50% chance of just going through and 50% chance of being reflected. and strictly speaking, this creates an entangled state with the beam splitter. so you have 50% chance that the momentum is actually actually redirected and the recoil is picked up by the beam splitter and in the other event nothing happens to the momentum. now the issue is the following. so you have some momentum going to the left and some momentum going to the right. and momentum is a physical thing, like you can measure it. it's definitely there. it's so small for a single photon that we can't in practice measure it, but it's something. and so the moment the wave function collapses, this energy and momentum that went to the one side in your mathematics needs to go to the other side. how did this happen? it's not compatible with einstein's theory of general relativity. that's just mathematically not possible. and so if you try to make this work within quantum mechanics, you need to do some weird thing where the energy from this particle actually went back into the past and then forward to the other side. and i think this is where these stories come from about retroca causality and mixed-up. causality and whatnot. but what i learned from this is that we need to think about how to quantify this energy so that it's compatible with general relativity because this is where the energy momentum conservation really comes from, which means it's got to have something to do with gravity.
i understood the question, but i can say something about this problem of borrowing energy from the future and stuff like this, because i was recently thinking about this, and i think this will make a nice closure, which is why i've come to agree with penrose that the collapse of the wave function got to have something to do with gravity. so forget everything about complicated quantum experiments, just imagine you send a single photon through a beam splitter. so beam splitters does what the word says, it splits a beam. so the wave function of the photon has a 50% chance of just going through and 50% chance of being reflected. and strictly speaking, this creates an entangled state with the beam splitter. so you have 50% chance that the momentum is actually actually redirected and the recoil is picked up by the beam splitter and in the other event nothing happens to the momentum. now the issue is the following. so you have some momentum going to the left and some momentum going to the right. and momentum is a physical thing, like you can measure it. it's definitely there. it's so small for a single photon that we can't in practice measure it, but it's something. and so the moment the wave function collapses, this energy and momentum that went to the one side in your mathematics needs to go to the other side. how did this happen? it's not compatible with einstein's theory of general relativity. that's just mathematically not possible. and so if you try to make this work within quantum mechanics, you need to do some weird thing where the energy from this particle actually went back into the past and then forward to the other side. and i think this is where these stories come from about retroca causality and mixed-up. causality and whatnot. but what i learned from this is that we need to think about how to quantify this energy so that it's compatible with general relativity because this is where the energy momentum conservation really comes from, which means it's got to have something to do with gravity.
Sabine Hossenfelder
on that note, please can we thank all of our wonderful speakers for joining us today. thank you to the audience. enjoy the rest of your festival.
on that note, please can we thank all of our wonderful speakers for joining us today. thank you to the audience. enjoy the rest of your festival.