On the Origin of Time — Thomas Hertog on Stephen Hawking’s Final Theory

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you want through brilliant again go to brilliant.org skeptic to get your 30 days free trial and the first 200 of you get 20 off their annual subscription rate just go to it right now why would you not want to do this this is so cool all right check it out and thanks for listening here's our episode what was it like working with Stephen Hawking give us a feel for the lab and when you guys when you say you work with you guys are working what is it you're doing when you're in that room 4 24 7 7 kind of occupation with Hawking right uh it never it never stopped he was uh obsessed with physics obsessed with live in general I would say um it was just very intense and a real really fun lots of lots of passion um but how did it work it's impossible to describe theoretical physics because the best thing is not to have much of a plan to be open to try to follow your intuition and I think what was Steven's genius was to kind of translate our intuition or his intuition about these big human questions like where we come from what's our place in the universe to translate these into what you could call uh thought experiments theoretical physics is all about doing thought experiments with mathematics and equations and theories and with these thought experiments you're trying to push these theories and these models and these ideas to their limits and you try to see where they break down and if they break down what is it why do they break down what is the underlying assumption that doesn't hold inside black holes or at a big bang and so forth and so it was a very I experienced theoretical physics as an extremely fluid imaginative intuitive driven yet mathematically grounded Discovery story there you go yeah I like that um so had he not died in what 2018 this would have been his next book Robert co-authored with yourself on his next big theory is that is that am I understanding that right well we both felt towards the end of Stephen's live in 2016-17 we clearly arrived at what we thought was a key new insight um a new a new picture a new a new vision of of the cosmos of the early evolution of the cosmos and shortly before he died he told me it was time for a new book so this is that book um at the time he could hardly he could hardly he could hardly speak anymore hardly communicate even even through his computer um I do think this book indeed as you say represents very accurately his thinking his interpretation of the theory of the Big Bang we arrived at but of course I've never been able to discuss the the broader bigger picture um behind it um in a sense it's all in our Publications you could say it's so it's all in our scientific Publications but the scientific Publications are of course technical and therefore structured and organized in a way that fits within the research field whereas these uh bigger questions um which by which Hawking was very much guided in his cosmology throughout his life I would say these bigger questions are are often only there in the background in our scientific work and we would discuss this as you say of over t or in the pep or over dinner or at night but what I've done in this book is to retell the story of our of our 20 years by putting these uh bigger questions from which our research emerged by putting these Central and leaving the technical details the technical details in the background and so that's the that's I think the the key the key point of the book so this is interesting uh because it kind of comments on how science has done the philosophy of science what do you mean a God's eye perspective on the universe you mean we can't get outside of it whereas you in a laboratory you can get outside of a a a you know a model of atoms moving around or something like that oh yeah yeah absolutely physics is um physics has taken a god-side perspective of vaccines Copernicus and Galileo it's the way physics has been constructed in invented discovered um it's reflected for instance in the fact that we have these laws the laws of physics are there as Eternal truths and we have uh boundary conditions which we impose which are not part of the laws and so you have some sort of external Viewpoint external input you define your experiment in your lab for instance um and then you let it go and this is fine this is really it has worked really great and in fact even in astrophysics and cosmology it is often fine because we rarely ask questions about truly the totality of reality in cosmology if you're interested in part of the evolution you can put yourself out of it you can put yourself before it or after it and again work with the standard physics framework it really only breaks down and this is the central subject this is the central question that drove 20 years of collaboration between Stephen and I it breaks down when you ask this deeper question which Stephen loved to ask like why is the universe the way it is why does it appear designed what is the relation what is the connection really between our existence and the physics governing the universe at that point you cannot stay outside because of course the question itself involves us and that really took us a long time to sort of break down this question and where is varies how do we change physics from within really to tackle that deeper question and so that passage that you were reading um indeed is the sort of key transition point in our collaboration or and in the book from the traditional God's eye Viewpoint to another Viewpoint which you could which Stephen would call a worm's eye Viewpoint from and sort of from the inside right um and so I introduce a little bit sort of the notion of a Hawking one and a Hawking two in my book or a Le or an early Hawking and a late talking and by the early Hawking I mean the one that took a God's eye Viewpoint the one that was looking for like like Albert Einstein or the theory of everything so as a sort of an eternal truth and by the late how King I mean the one yeah the the one that change this mind where scientists should change their mind when the evidence changes or the the arguments are are changing or whatever I think your new book is also something of a sequel to uh sorry we're getting a little bit of a delay I was just going to ask you about the Grand Design because it's also something of a sequel to The Grand Design or a different perspective right uh what did I write here um you replace you're replacing the Multiverse which was the presentation of The Grand Design more or less with a darwinian model of cosmology and Grand Cosmic design but Grand Design I mean the word design that that something of a I mean because it isn't designed because people think design they think there's an outside designer but that that wasn't the point of that so so how is this different from The Grand Design well as you were saying The Grand Design you could uh frame so to speak where Hawking is sitting on the fence a little bit it's sort of in between the the early and the late hockey and on the one hand um he argues indeed against the idea that there is a kind of unique equation a formula um a theory that dictates How the Universe should be that would be a little that equation would then function a little bit like uh yeah a designer or or a transcendental truth or so um and on the other hand but on the other hand he's still holds on to that Multiverse idea which we then say goodbye to in in our later World in fact by the time the Grand Design was published Stephen was already quite a leap further further Hawking had had long doubts on you could see the Multiverse as another kind of explanation for the design question what do we mean in fact by this design question we mean that uh the universe at least at the level of the physics at least at the level of the laws of physics seem to be just right for life to emerge the laws of particle physics the the composition of the universe the expansion history everything seems to be just good and so that evokes this question why did the Big Bang get it store get it totally right um so then you the first kind of explanation was okay maybe there's an equation behind it I think that was what Stephen and many others and Einstein were thinking in the 80s Einstein not of course but even the 80s um and the Multiverse gave a completely different viewpoint on this if there are many universes and uh we are just in one of them but there is a a huge number of universes and many of them can be sterile many of them cannot be suitable for life to emerge well and many of them can even have different laws of physics well once in a while you're gonna find one which is good and surely we should be in a habitable universe but I think Stephen was one of the first scientists first cosmologist to realize the uh depth of the problem with with the Multiverse the fact that it is not testable uh not falsifiable the fact that invoking a zillion other universes to explain this one um was not the way to go but of course it's easier said than done to then find an alternative of the um that does work right and so that's what we that's what we developed essentially by taking a profoundly Quantum viewpoint on the earliest stages of our universe um okay so let me just see if I can rehash this for our listeners because I'm not in this field at all so I can ask the dumb questions the problem to solve is why is the universe tuned the way it is to give rise to complex uh organisms and and Consciousness and us and so forth the the week that this is the anthropic principle so the weak one is that well the universe would have to be designed this way for us to exist we can only be asking the question in a universe like this the strong version of that is that some outside designer made it this way for whatever reason wanted to bring us about or whatever something like that and and so the invoking of the Multiverse is often done to say well there's you know countless universes and we just happen to be one of the ones with the laws of nature that gives rise to us and there's others that have laws of nature that don't give rise to cosmologists like you and people like me to ask the question so that's the problem to be solved the Multiverse is one solution if it's not testable if it not even in principle then it's not science what is it metaphysics or philosophy or religion or something like that I guess and so what you're saying is that in this book you're trying to get around that and actually produce a testable hypothesis for this problem have I said that right right but when I say it's not testable it's because the entropic principle introduces ambiguities in whatever you predict so the anthropic principle plays the role of selecting a universe in this Multiverse the problem is that depending on what you call entropic observables or entropic properties of the universe and what I call entropic properties of the universe may be different and so both of us are going to land in a different universe and going to predict different physics so it's kind of it's almost like a it's a breakdown of any sort of scientific predictive framework whatever you put in you get out and if it doesn't agree with observations you can put something else in so you can always trade some sort of failure into a success by changing your assumptions about what you feel is entropic and so we we have a name for design the field uh it's a well-known name it's called a measure problem we don't have a good way to measure the weight or the relevance between different universes in them and I think what happened in the last 20 years is that gradually it dawned upon the community of theoretical physicists and cosmologists that this measure problem that we were facing in in Multiverse cosmology was a a really deep problem going at the roots of physics and then of course the question comes okay what is it in the roots of physics that is preventing us that is blocking us that is obstructing progress and that I think was really the core of my my entire uh Voyage which didn't so I'm rephrasing what you were saying so yeah yeah but so just one more pushback on this set so theists that I debate about the existence of God who are invoking the fine-tuning argument and so on we'll say well this Multiverse thing is just a hand waving argument to wave away God or a design intelligent designer it's your faith it's no more testable than my God as an explanation so each of us has an explanation who's to say who's right wait so is that a question uh um well I've just if you heard that argument from a theist saying you're just making this Multiverse thing up uh so you don't have to be invoke the god hypothesis okay okay right so in a sense I agree is a big word but I do agree with the statement that the Multiverse as it stands in conjunction with the entropic principle is not proper science and therefore indeed on the same footing as many other kinds of explanations but this was precisely the motivation and reason for us to revisit our scientific principles and to come up with a model of the early Universe which is falsifiable testable or at least which Pro produces unambiguous predictions because that's the starting point right when we say the Multiverse is not testable it is not because we can't go to another Universe to check it out no it is because the Multiverse Theory does not lead to unambiguous predictions for what we in this universe should observe and that one is something indeed which is from a scientific approach unacceptable okay let's get into your theory so the book is called on the origin of time what is time time used to be something pretty metaphysical for Newton it was pretty metaphysical right it was just there like an absolute it was absolute time in Newton's time um but um Einstein made time into a physical field like any other and so that became a lot more interesting um but then of course the big big implication of Einstein's theory of relativity is that both space and time can be curved and and and and time can flow by different rates but the biggest implication of course is that time can end inside black holes and again and begin in a big band uh so there is a sort of really profound uh or you say the finiteness sneaking into physics at the level of space and time that's the legacy of Einstein's theory I saw the origin of time why is my book called the origin of time for two reasons but the first one is of course that the Big Bang is not just an explosion but it's really as best as we know the origin of time of the past the the past limit orbast okay but even the concept of an origin of time because then I mean maybe this is just a restriction of our cognition uh and our Concepts but you know how what we I can't even ask what was there before time right because that's right that doesn't even make sense so I'm not even sure how to ask the question what you know why would how what was what did the bank what banged the bang before there was nothing that's right that's the question we have to we have to give up on and it's very explicit in in in the final theory that that Stephen and I developed um because Loosely speaking in the model of the big bang that we developed time going backwards is an emergent phenomena and phenomenon and every emergent phenomenon has its lipids and it's almost like as if we're losing the dimension of time when we deliver deep into the Big Bang Hawking used to say that time sort of wow he used to say confusingly that time became imaginary by which he really meant that the dimension of time bends into a space Dimension and of course then as you as you were saying then asking questions about causality or cause and effect it just it's just not possible anymore but losing the dimension of time is is key is a key Insight I think of Einstein's theory and aha the problem was that Einstein's theory um couldn't answer really anything about what then happened and that's because Einstein's theory was a classical Theory and really it put that origin of time strictly speaking from a mathematical Viewpoint Einstein's theory put the origin of time outside physics outside science so as a sort of unanswerable question which of course he didn't like himself and that was the reason why he was so much against the Big Bang uh because of course he saw that his old theory was was doomed at the Big Bang um and how he developed famously yeah this this sort of geometric way of thinking so a kind of Einstein kind of thinking about space and time but he developed this but anyway you could say that he sort of bent space and time further Daniel Einstein dared to do and unlocked uh the quantum reality of space-time where the time Dimension can disappear as it does in our model in in the Big Bang and so yes I'm sorry there is yeah let me let me know oh well so I was gonna I was gonna I was gonna point out the the infinite the problem with the infinite regress series of arguments in any case is the theist doesn't has the same problem you can just ask well where did the intelligent designer come from who designed the designer and you know at some point causal explanation just has to stop you just have to say okay we're going to start our model here and run it forward so you guys are starting just right at the big banger shortly after and so then what happens there's like just a Quantum field or something this is where quantum physics comes in and the problem you're trying to solve is how to square that with einsteinian relativity right because I I think you're right so what what differentiates this uh model from uh the infinite regress kind of reasoning which by the way includes the Multiverse right because in the Multiverse we say the Big Bang was not really the Big Bang but there and there there are not just our laws but there are meta laws governing the Multiverse and there's a bigger space and so forth it's very infinitely rest kind of reasoning indeed so what differentiates our models from those models is the we accept a genuine origin and we try to model a genuine origin and that's why um I have made the analogy with darwinian thinking because as you as as we all know darwinian Evolution happened to an interplay between variation and selection but if we trace the Tree of Life backwards the laws of biology disappear and we have a genuine origin and before that origin we have no biology and no laws and no no rules of mental no laws of DNA and whatever Stephen the model that I developed at Steven is very similar it's a genuine origin but now at the level of the laws of physics so our statement is that if we go deep into the Big Bang we have a similar kind of evolution as with similar kind of principles as Darwin's but happening deep down at the level of the physics a series of transitions in the earliest stages of the universe through which the forces Diversified the types of particles emerged and that's sort of the tree of physical laws if you wish that we know today took shape some kind of a co-evolution with the with the early universe but the consequence is that if we go backwards deep into the Big Bang we lose that diversity the laws become simpler more symmetric and the last transition is the one in which time morphs into space and with that the laws of physics themselves disappeared just like the laws of biology disappear at the origin of life and that is I think the key point it gives a completely different sort of picture or Vision uh yeah what cosmology and physics are ultimately about it's much more um some sort of it's almost like putting the The evolutionary character of the physical laws uh finally uh up front and Central of course that Evolution happened deep deep into the big bang and we and we know very little about it and that's also the reason why we think of the laws of physics as Eternal truths it's a kind of evolution which was frozen a fraction of the second after the big bang and we build up the entire universe on that Foundation I we're kind of saying there you we shouldn't think of this as a foundation with the big bang also the laws disappear that's that's the Crux of our of our team interesting so you're saying that the principle of uniformitarianism that is the laws of nature that we observe here on Earth probably work the same way on some other planets say geologically speaking or astronomically speaking the gravity operates the same way in other galaxies and so on and we can make that assumption and build our models from there but what you're saying is if you go back far enough in time that wasn't always the case the laws of nature changed or they're different now than they were then something like that yes but deep deep deep into that earlier stage of the Big Bang exactly yes right could it be something like you know that problem of explaining the acceleration of the expanding Universe maybe this but what's the explanation of dark energy right maybe that is itself a different no I'm not saying this right are the laws of is that law of nature different than than it is now something like that in a sense that is also what our what our model says You must have heard about inflation right the sort of the the very rapid phase of expansion in the early Universe which is driven by essentially a kind of dark energy which uh is envisioned to have been a lot larger than than it is now so indeed if you if you think about a dark energy and the cosmological constant as yeah and for all purposes that's correct as a law of nature today during inflation that law of nature was very different can I ask you another kind of philosophical question on laws of nature what are they I mean it's almost like the concept is reified like it's a thing that's out there to be discovered but in fact is it actually just a mathematical description of what objects do when they're interacting in space something like that okay that's a good question um in a sense it's it's at the heart of its eye it's at the core of my book right um because what I was just saying implies yeah if the Wolves themselves dissolve into the Big Bang then we shouldn't think of them as Eternal transcendental truths uh then we should really think of them also as a product of evolution it's just that the evolution uh is hidden from it it's hidden deep into the heat of the big bang and we have almost almost no fossils of that earliest earliest deepest stage of evolution that's in a sense you could say that we're kind of in the same boat as Darwin in the 19th century who had no who had almost no fossils to put together his idea right um so it's a bit similar head but the crooks of my title on the origin of time I I told you about the first reason for the title the first reason was that the Big Bang is the origin of time but the second reason of course is that it's a variant of Darwin's title On the Origin of Species so I'm trying to convey the message that we should think of the origin of time as a kind of evolutionary process driven by Quantum Randomness and Quantum selection in it on its own um and so you could then ask the question and this was your question I'm sorry I'm digressing um what is then the foundation of these laws if it is not if it is not if the foundation is not to be found in profound mathematics that somehow transcends our universe well then I think the foundation is and this is sort of the crooks of our of our Theory it's sort of upside down it the laws are contingent on our perspective as observers in the quantum sense within this universe just like the law that all life of on Earth is based on DNA and Mendel's Laws of biology are contingent or regularities patterns in nature which you can discover and exposed facto only but not as prior truths if we were to rerun the evolution of the universe or if we were to rerun the evolution of life on Earth we would arrive at a different tree of laws and we would arrive at a different Tree of Life That's and so in a sense I'm trying to ontologically because that was your question your difficult question ontologically I'm trying to put biology and physics um on more of an equal footing oh well I was going to follow up on that because you quoted in there in your book um Steve Gould's thought experiments on rewinding the tape of life and playing it back again so let's explore that for a second uh you know Dan Dennett was the first to point out in his book Darwin's dangerous idea he has a whole chapter on Gould that technically if it's a read-only Memory tape that you're playing back it's going to be exactly the same because that's just a recording of what happened but what Google really meant is not a literal tape but just just go back to the start of time and rerun it again and you get these contingent events like the extinction of the dinosaurs had that not happen mammals would probably not have evolved to the extent that they did and we probably wouldn't be here okay so from there the question is to what extent are the laws of nature fairly well determining I mean the channel the channels of variation that you can get are fairly narrow or are they fairly wide so for a while I I I like Gould's uh rewind the tape argument and the role of contingency but then your colleague over in the paleontology Department there at Cambridge Simon Conway Morris you know wrote a book in response to Gould's argument particularly over the Cambrian explosion that in fact it's not as random as you think there's something called convergent evolution and then if you rewind the tape you're going to get organisms that look more or less alike like if you're a organism in the water you have to have something like a fusiform body you know with fins on one end and a mouth on the other or if you're a if you're a mammal you have to have limbs to move around on the land and you got to have you know the sensory equipment on one end and the Waste Disposal system at the other end and so on there's only so many variations on a theme right so if we did encounter aliens they're not going to be exactly like us of course but bipedal primates but they if they're if they're land-based they have to have certain kind of structures to survive so they're going to have something like eyes and brains and ears and and wings if they want to you know survive in the air and flippers and a fusiform body if they're in the water and so on uh and so I always thought that was an interesting debate you know there's no I don't know what the solution to that is it's some tug and pull between contingency and chance versus the laws of nature so now apply that problem to what you're arguing for cosmology to what extent do the laws of Nate if you rerun the universe we'd end up with something like what we have or we're not cool great yeah so indeed as you were as you say it's it's it's really this interplayer between uh constraints which often often come from from the lower kind of levels of evolution the Earthly environment for instance and and and the oceans what are you gonna do you're gonna do some develop some sort of life that is adaptable to that um situation um the same with the famous uh John Von Neumann taught experiment about DNA so John Von Neumann drew a kind of um cellular automaton really yeah sort of a kind of structure which he envisioned uh uh could reproduce itself and he drew this structure way before Watson and Greek discovered DNA and if you compare the two of course they're not the same but rap in it roughly you can you can see you can see similarities and so that is extremely interesting that for Norman purely on computational grounds arrives at something like um DNA um so at all levels there is this debate between what is the what is the Divergence Divergent forces and what are the convergent forces same with same With Yuri Harare who who studies human history and who argues that this is an extremely Divergent uh process um so in that sense Simon Conway would have a hard time I think arguing also at that level for convergence so now we did now we descend to the level of physics what are the constraints and um and I I yeah I thought about it and and I discussed it in my book um and also there you have you have you have the same the same in the play that you mentioned between um convergence and Divergence of course there's there's not much contingency because uh the further back you go the less the more primitive the environment really is two things if unification involves these extra Dimensions that string theory envisions the scope for variation seems extremely extremely large and compute a uncomputably large in fact that's all um so that's that's that's a strong Divergent argument which probably plays out in the very early transitions where the shape of the extra Dimensions is also involved in shaping the effective laws that emerge on the other hand there is this deepest layer the one that we were mentioning earlier the layer at which at the bottom where time turns into space that is a contingent element in our model that is a constraining element that is something you can't just get away that that description of of really sort of closing physics closing time that is constraining not everything not everything goes there for instance that that sort of last transition goes together very much it resonates with this idea of inflation that we mentioned and inflation of course will be a small will that that that will select a subset of possible universes and so not not everything will be possible there and so I completely agree that is the interesting thing to develop now what is contingent what is necessary and the way we phrase this is what are the correlations if this and this and this then it the universe must also have that and that and that property um yeah this is this is largely an explored uh territory yeah but it's a little bit like what biologists it did that do I if you if you sort of try to reconstruct it to the Tree of Life in great detail you're gonna find on the one hand correlations between all these species on the other hand you're gonna be confronted with accidents here and there uh at the level of mutations or at a level of the environment and then so forth which uh have taken his biological history in a certain direction I'm going to point out just parenthetically it's not Central to your book but since you mentioned Harari and and kind of the contingent nature of human history I don't think it's I would disagree that it's not that contingent it's not that random now it might not have been Christianity per se but any religion that doesn't require much to join you don't have to give up any foreskin if you're a guy that's that's an incentive to join right and if you have a missionary program and you have a high fecundity program your religion is going to grow versus if you have no missionary program like Jews you know they don't they don't go out to proselytize right so they're numbers and the educated Jews don't have very many babies right so you know or something like the rise of the nation-state you know if you have enough people crowded in an area you need some kind of Leviathan to run the show and have a court system and so on you need something like a nation-state with a legal systemism so there maybe there's a certain amount of inevitability not inevitability but constraining laws yeah yeah I agree with that but I do think the constraints and the contingency are mostly operational on the sort of large Arc large features uh coarse grained properties and such like the rough form of DNA or the rough flow of history or the fact that most of human history has played out on the surface of the Earth yeah sure stuff like that but I think it's more in the nitty-gritty details uh in the fine structure in the specificity of the complex systems that we find Randomness um dominating and the key question is that indeed in this giant space of possible universes do we where is that balance between random accidents and on the one hand and as you say contingency so far I've only sort of within the within this model that I discussed with Hawking that I developed with Hawking it's only some sort of no some notion of early inflation that I see as a key necessary [Music] um feature and of course it's not nothing because as you know it implies an early phase of inflation implies there will be some sort of seats for stars and galaxies and so yeah you're on a certain trajectory which excludes other trajectories yes okay I see can you explain first the double slit experiment which you discussed in the book and to what and the different interpretations of that because I think one of the Multiverse hypotheses derives from that all right and and then how does that influence your theory with Stephen uh uh yes yes we can we can discuss this [Music] um the total split split experiment um so you fire particles or photons through two slits and you put a screen behind those slits and you'll see what happens and you'll find that if you read this experiment for a while you see some interference pattern arising of the screen and that interferency pattern arises even if you fire and that's the crucial point particle by particle once one particle by one particle so if you Dim your your light source or if you Dim your electron gun so much that it's only one Photon or one electron at a time that goes through if you wait for a while still this interferiency pattern arises and so that showed that these individual particles somehow know about boat slits that they have a bay flight properties which and so that they interfere um when when they go wavy through both slits and that would then result in in that pattern uh if you if if you keep going and so that certain probability to arrive on difference what's on the screen is is different depending Where You Are um so there's a there's a genuine uncertainty in which slip the particle in the particle comes through and the way that the double slit experiment sort of enters enters in my book uh is too twofold really at the first level is the one that I explained you can um you have to describe those particles as probability waves wave functions the second level is really um once you start probing once you add a layer to the double slit experiment and you probe yeah okay let me add a detector let me check to True which slit this particle really came so you sort of try to cheat and when you cheat the particle will adapt in a way and the interferency pattern will disappear and you will know which slit particle came true but your interferency pattern will will disappear and this sort of create John Wheeler came up with it with a beautiful sort of variation of this setup he said all right so this is interesting if we'll look at the particle we know which lead it goes through but we lose the interference if we don't look we have these interference what happened he said if we decide to try to trick the particle and if we place the detectors not at the two slits but further down at the screen and so we only won't we only decide after the particle has gone through the slits whether we are going to look for where it came from through which slit or whether we gonna just let it hit the screen so he sort of turned the slit the screen into a venetian blind which you could open and close in his thought experiment right I told you theoretical physics is about thought experiments which he could open and close after the particle had gone through the two slits so that was a truly genius experiment thought experiment which Since By the way has been performed and and um and so the particles always get it right if you decide to close the valetian blind then do the usual thing you get your Infinity pattern if you decide to open the venetian blind and put the test put the detectors at work to see which slit particle came through you'll find no interference pattern how is this possible how can a particle know in advance what you the Observer will do at a later time it is truly beautifully it's truly beautiful quantum theory and the reason is how do we explain this how does quantum theory explain this quantum theory explains this precisely by really describing these particles as Bay functions as uncertain ghostly wave functions which really don't do anything concretely until we ask a specific question until we specify whether we're gonna close or open divination blind that decision that act of observation turns the wave function the past history or determines what we can say about a past history of those particles what a facet of the particle's wave function manifests itself as a as a tangible reality and now you see me coming and I think that's why you asked this question um how can essentially after the Multiverse paradoxes drove in math how can essentially decide that we're gonna have to take a profoundly Quantum Viewpoint we're gonna have to in order to sort of get a grip on on the Multiverse or to do this differently and so he essentially took wheelers particle Quantum thinking and applied it boldly to to the early Universe to the big bang and that's what our theory is about that was a long explanation no no that's a that's a good start because I think from there much follows but on this just a clarification The Observer doesn't have to be a sentient being right it could just be a camera or anything that the particle interacts with oh yeah yeah so this is a common confusion and it's good that you ask this um no no in fact it's rarely human being down at the quantum level the actual Quantum observation that we interact with has already been done uh by the environment uh even even a lone Photon of the of the microwave background could be a Quantum of a could act like a Quantum Observer um and if you think about the early Universe where we have where we don't even have yeah particles and and then it is really the interaction with the primevals the interaction between the Primeval fields that were around that we're doing the observation so it's the universe itself which acts as a Quantum uh Observer uh sure sure this is this is key well I bring this up because as you probably know that there's a lot of quantum Consciousness uh ideas floating around out there that somehow it's Consciousness that brings these things into existence or determines the way things unfold and maybe there's a cosmic Consciousness or God is consciousness or we're as conscious beings Godlike or something like that so it's not sentient's Consciousness in that sense that you're talking about here with the double so that experiment but then there's that related one you know the Einstein called spooky action at a distance right the spin of one subatomic particle determines the spin of another one on the other side of the room the other side of the Galaxy the other side of the universe how does the information get there across there and as I understand it it's not it's not exchanging information it's something else going on maybe you want to comment on that problem yeah so I totally agree that it did that this is not about Consciousness in fact I think I I once brought it up uh in my discussions with Hawking and he immediately blocked it um sure sure this this Quantum active observation is something more fundamental something more basic foreign of course that the the entanglement that you refer to Einstein's spook reaction of a distance uh spooky action on a distance yeah yeah that's also a sort of information but there we what's spooky about it is the fact that the information is not encoded uh right here or right there but really in the entanglement in the connection between two distant uh particles and um so that's yeah that's a genuine Quantum form of information you wouldn't be able to do that in any in any classical way right but very important it plays an important role in our in our later work and it plays an important role in um Quantum Computing for instance right right I love another passage here that got my attention from your book uh book in a recent tribute to Wheeler John Wheeler Kip Thorne Kip Thorne recalled the lunch with him and Feynman in 1971 at the Burger Continental near Caltech a diner Stephen too frequented while at Caltech we used to hold our skeptic dinners uh at the Burger Continental after our lectures at Caltech it's really funny oh really uh and then over American food wheeler Armenian food wheeler described to us his idea that the laws of physics are mutable those laws must have come into being what principles determine the laws uh which laws emerge in our universe so this is kind of what we've been discussing so just parenthetically the feynman's idea of some over histories is this along the same lines that you're talking about here there's just particles could take all the different Pathways but but they're more probably likely to take one versus another one yes it's it's yeah sure sure at the level at that level that that's what it is right um fireman's formulation of quantum mechanics is a very useful a very tangible way of thinking about these wave functions particles take all sorts of roots and so very importantly you can't say you can't you can't say you can't say much about it without asking a specific question and the kind of observation or the kind of question that you're asking determines which parts um so to speak become yeah real I dare say um become yeah rise to the Forefront and so the key here is that there is a sort of retroactive aspect sneaking in cosmology when you do it that Quantum way because the contingent configuration so this is what Stephen called a top-down perspective on the Big Bang so he if you think Quantum mechanically you don't think just in terms of a prior state which you evolve deterministically forward no you think about an abstract wave function which doesn't really provide the answer to editing until you really specify a situation an observational configuration and that is like asking a grand question of that abstract wave function which then crystallizes for you a history or a subset of histories including if you go back to the earlier stages a specific sequence of transitions that crystallize the effective laws which you have yeah right and by the way Murray Gelman was a long time supporter of the Skeptics when we first started he called this Quantum flap doodle this whole idea of you know extrapolating from quantum physics uh all this kind of Eastern mystical philosophy and psychic power and all this kind of stuff anyway that was kind of funny so I was reading from uh this quote from Stephen Hawking in his no boundary theory that he presented in A Brief History of Time the universe would be completely self-contained and now affected by anything else and not affected by anything outside of itself it would neither be created nor destroyed it would just be and then he famously finished that line there that paragraph with what place then for a Creator which caused a media fewer over that so when you're talking now about a top-down model of cosmology you're this is different than the no boundary as I just described it's a different interpretation of the new boundary and it's a further interpretation of the no boundary so okay the paragraph that that you were just quoting is the is what I called the Young Hawking it is the how King who was looking for uh the ultimate formula for an equation that would describe how and why the universe was created indeed just like Einstein the idea was that that equation both the early Hawking and Einstein I think believed very much in Spinoza's God that this would be sort of the ultimate expression of uh a god-like Harmony and um the old no boundary proposal didn't work because it predicted an essentially empty Universe without observers if you wish and without galaxies and so this was and as a consequence of course the theory remained controversial but somehow but so this is my this is my impression in all these years I worked with Stephen and we didn't really have also also before we came to that damn View but he never doubted that theory even though of course he knew it didn't work but he for him the new boundary proposal I mean he once he once told me he thought that was his greatest discovery he had had this intuition that that he was right but of course he couldn't get it to work and the reason is that he took these God's eye view on his own Theory so I think he underestimated the his own Theory just like Einstein did once we took this once we took a Quantum interpretation once we put ourselves inside and worked top down worked exposed facto The robundy Proposal thus select uh reasonable reasonable histories but it comes it comes with the altological or epistemological consequence that we were discussing earlier namely that you no longer regard it as a transcendental prior truth that's that tells you how and why the universe was created but as a mechanism for essentially closing our past and let time disappear and in a sense imposing a certain a certain finitude in science um it's almost like a statement that um there is a kind of limit to what can to where the laws reach I would say so it's a very different interpretation and a huge right because a huge philosophical shift right because you uh have another quote from Hawking the anthropic principle is a council of Despair it is a negation of our hopes of understanding the underlying order of the Universe on the basis of science yeah that's a cool one but you also have here another quote from Hawking the history of the universe depends on the question you ask now that's a Curious Thing uh it's almost like um it's dependent on well what did Hawking call that in in Len Milan now and The Grand Design model dependent realism reality depends on the model you're using you're doing something different with this now though right yeah he never he never mentioned that to me uh the model dependent realism um that quote when he told me when he told that to me um it had everything to do with the a sort of his his somewhat intuitive poetic uh oracle-like way of describing um the act of observation in the cosmological context um by the question you ask he essentially meant okay um we have this and these these and these properties and physical forces and particles and so forth it is the top down input it is the analog of Darwin's fossils which select in conjunction with uh the the dino boundary origin um a subset of histories that contribute to our observations so I interpreted but maybe I'm wrong man but at least when my interpretation at the time when he told me um that was all in the context of our discussions of of um what what among the two of us and what I in my book in in chapter six called top down cosmology right since I only read the books and not the technical papers just tell me what just tell us what the reception so far to your and Stephen's theory has been from your colleagues in the papers that you've published right so in the papers of course we did not develop that broader darwinian um more ontological bigger question picture for that you have to wait till the book appears in the states uh to see the reactions at the level of the of the papers the last series of papers where especially geared towards implementing that Quantum View uh using the uh holography yeah using the discovery of horography in theoretical physics so you've probably heard of this right that in the last 20 25 years uh holography has been has been yeah the talk of town among theoretical physicists and um because we see in holography a way for quantum theory and and relativity to work together and of course holography has mainly been developed in the context of uh either black holes where from a Quantum holographic perspective uh you would say that the information that everything you can know about them like oh is is located on its Horizon surface and in the context of again taught experiments with end with in in highly yeah in mathematical artificial universes that don't expand but where we can um get a handle on um so to speak the dictionary between on the one hand the quantum description and on the other hand the gravitation description what I did in the last few years with Hawking and which is turning into a field of its own is to apply these holographic ideas to the early evolution of an expanding universe and what was one of the what was one of the wonderful Eureka moments between us I would say is that the no boundary idea which you mentioned the whole time goes into space Construction is in fact what emerges from taking a holographic perspective so very important point is that when we talk about holography when we talk about a hologram we always think that the extra Dimension that sort of pops out of the Hologram that this is an extra space dimension but when we apply these ideas of holography to the early evolution of the universe we found that it is the time Dimension that is the emergent one the holograph the holograph the hologram sort of encodes in Einstein's spook reaction way but extra Dimension but that extra Dimension is the past time Evolution and if you think about it this is exactly what cosmology needed for 90 years we have been confronted with the problem of the origin of time the Big Bang is the origin of time and so it's you're not gonna solve this as long as you don't have a model in which time is not a fundamental thing that you put in a priori but which in which time is an emergent phenomenon and to my amazement holography does precisely that and so and it clicks it fits it resonates beautifully with the no boundary construction that Hawking and hartle uh came up with in the 80s and so in in interesting yeah so time is a you would describe time as an emergent property of the laws of physics that is correct and that and the laws of physics contingent on our observational situation those are the two great ideas in my book yes I mean to be clear I mean if it wasn't clear already I'm gonna say it uh to be clear this is of course a grand hypothesis right as we were saying earlier uh it's a little bit like the like Darwin in the 19th century this hypothesis uh will have to be developed on theoretical grounds this holographic view of cosmology of time has to be developed and understood uh in great detail and one can also hope it can be tested we at some point one can hope we can get our fossils of the big bang by looking deeper into the um into the into the earliest eras right and so I viewed the observations of the early Universe a little bit as the analog of the fossils that are we needed and I view holographic cosmology a little bit as the analog of um say genetics molecular genetics which essentially provided the microscopic mechanism behind the Darwin's speech yeah so there's interesting I just point out in the history and philosophy of science that you can develop a theory without a mechanism as at least a place to start and in the future test it and find the mechanism Darwin didn't have a mechanism for genetics that we don't get that until quick and Watson right and yet the theory of evolution was accepted because the evidence was overwhelming that it was happening whatever it was down at the molecular level that was happening and you know Alfred Wegener proposed that continents were drifting in the 1930s and it was pretty clear that something was going on because the pieces seemed to fit but it wasn't until the 1960s that we had a mechanism of plate tectonics driven by these huge um uh fluid cells underneath the continental crust and so on so what you're proposing is that there probably is an underlying mechanism in these laws of physics that we can get to through the Hologram or whatever model you propose there would ligo testing for gravitational waves be 1 form of testing or might the James Webb Telescope find something or how how are we going to know say in the decades to come right right yeah very good question um yeah so James Webb looks at photons sadly um and so it's not getting us far enough back into the earliest stages uh but you're right that in principle of gravitational waves which uh even the earliest stages of the Universe um right at the Big Bang in fact or or even uh in that inflationary phase which is a fraction of a fraction of a second gravitational waves just travel through it the universe is transparent to gravitational waves still from its birth onwards so you write that probably there we we have the those are probably the fossils we should be hunting for um the various transitions in the early Universe which sort of um crystallized the the law the effective laws of physics say those various transitions are pretty violent and can go together with bursts of gravitational waves those bursts of gravitational waves should still be around but of course by now they're they're buried they're buried under under a total holder gravitational waves that have that have been created since and so these are not the signals that that ligo is gonna see you will need a future gravitational wave observatories with a better precision and probably um a much longer wavelength so a much larger observatories maybe space missions like like Lisa um to really hunt for these uh primordial gravitational waves as as you could uh say yeah but yeah yeah that that would be a very promising route sure interesting okay Thomas I think I got the big picture here from uh your book of your of your theory with Stephen um you also have a quote from Stephen Weinberg so let's just pull out and look at the bigger picture for as we close things up here the more the universe seems comprehensible the more it also seems pointless I think this is what bothers uh you know religiously minded people with the kind of stuff you're doing like you're really bumping up against the ultimate questions here right and if you're what you're describing is just doesn't need a Creator or a designer then what's the point of it all how do you come to grips with that question I I take a different view why I mean I I I I I yeah I quoted Weinberg there but I also wrote that I don't share his feeling and I find that well Weinberg was one of those people who were brilliant brilliant scientists but he too took a God's eye perspective on the Lost and ontologically very fundamentally if you're gonna drive at those biggest questions in a way that separates The Human Condition from the laws that you're discovering it's never going to be satisfied I'm trying with this book to give us the outlines the rough outlines for a different worldview in which there need not be a separation fundamentally between the laws of physics and our existence in which the laws even at the bottom level are contingent on our human condition and it comes with a certain finalness I give up on prior truths and eternal truths but I think we're gonna emerge stronger from this and we already are emerging stronger for instance big contrast to the Multiverse we now have a model which unambiguously can predict correlations between this and that between between our our certain properties relevant for life and other properties of the universe so I think it is in the interconnections in the correlations between different facets of the universe that we might eventually find this um a positive role View I like that that's good right uh I I knew Stephen Weinberg a little bit mostly because traveling in atheist circles so he did have something of a reputation of being a little kind of an angry atheist a little bit um and so maybe some of that fuels the interpretation of comments like that um yeah yeah it's interesting um you know you talk about the early Stephen Hawking and the later Stephen Hawking it's the kind of thing you hear like the the early Van Gogh before he was an impressionist and then the later Van Gogh we came became well there was no impressionist ISM to come he created it in part or you know the early Jackson Pollock or the later Jackson Pollock but I like to think what you're doing is more than art it's not just an artsy Trend right that could go this way or this that way hopefully it's driven by well mathematics and empiricism what you know look out the window what's the world actually like sure sure so I you're touching on a very important point um Stephen refused for absolutely and consistently to uh talk about uh philosophical positions independently of our uh scientific work so he he loved to sort of attack the most fundamental questions to try to attack these to try to study these on uh with our models and and in the scientific context but never sort of freewheeling philosophical thoughts uh at all and so the early and the late talking is is yeah it's a good point it's not about ah I'm Gonna Change philosophical position no it is being forced to adopt a different position because the mat is driving you towards this um so it's a it's it's yeah yeah no it's it it was cool right on the one hand he denounced philosophy on the other hand his scientific work was philosophically pretty productive yeah I remember when he made that comment philosophy is dead all my philosopher friends were like what yeah I'd say that I mean because in a way what science itself is a kind of branch of philosophy you are doing philosophy when you're doing science that's right that's right that's right yeah yeah yeah yeah all right last question uh for you personally or as a scientist is there room for a deity or God in your epistemology and cosmology at all is it just a mystery is it just you know we don't know and never will or how do you think about that well I'm not religious personally but it didn't Escape me that um the picture that we arrived at in which you let physics in a sense disappear into the Big Bang comes with a certain it's it I I think it creates room or space for different spheres of thought it it's a picture in which science does not claim to be giving us the absolute answers but more a picture in which science seeks deeper and deeper interconnections between all facets of nature and so Loosely speaking you could say I'm not sure Stephen would agree with this uh Loosely speaking I think it's I think it it leaves it leaves some space for mystery and therefore for all the Spheres of thought religious religious spheres I think what's important is not to mix these two um there is there is not one universal language or one universal answer it seems to me that uh science serves its purpose and um religion serves different purposes and there's no need to there's no need for the two of them to interfere all that much um yeah so pragmatically speaking that is often the case that's true I mean you don't go to the paleontologist for your your morals right right on the other end maybe philosophers have something to say about it as well or scientists when they're doing philosophy something like that yes I can see that and I you know some of Steve Gould's non-overlapping magisteria you know is admirable in terms of like can't we all just get along yeah okay that's good uh but on the other end there are conflicts you know at some point the Earth is either ten thousand years older it's four and a half billion years old it's not in between there one of them is wrong right so you know it depends on the claims being made by the theist I guess yes I do agree with that I do agree with that um sure sure um yeah yeah the entire uh religious literature should be very very much viewed as a metaphor uh the statement that you just made is religion coming in uh coming into scientific terrain that is that it that that that's not the idea no no that doesn't get us anywhere um there was this priest astronomer Giorgio Le maitre that I also write about he was the one who in 1931 came up with the big bang and then Albert Einstein complained he told him like look Giorgio Le maitre this reminds me of Christian DOMA and then labatre being the priest try to explain to Einstein no no no this big bang physics is gonna be science like any other science um it leaves out God Elementary he had an idea of God as a what he would call a hidden God so don't invoke God for any scientific concrete inside don't try to say what he or that implied but more sort of as a as a spiritual Force I think and so I think he tried essentially beautifully to separate religion and science but yet leave space for both spheres of experience or false false fears of thought I kind of like that vision yeah I would point out your your book also makes it clear how young cosmology as a science really is in terms of actually collecting data right I mean like 1990s not like centuries old right so I mean a century from now we may have a completely different understanding of this so it's too soon to say you know that this is probably true or that's probably true we're just pushing the envelope here yes absolutely absolutely this is in full swing um and then if you if you think about what we were discussing about gravitation wave Observer observations or these ideas about holography sure sure uh in 20 years someone is going to have to yeah it's gonna be sort of a serious reading let's hope let's hope that science that's what science is about right uh it's a whole Discovery story and it continues one generation all right Thomas that's a good place to end you can on the origin of time in 20 years you can write the second edition when the with the new discoveries Stephen Hawking's final Theory there it is on the origin of time nicely done beautifully written really enjoyed it thanks so much for coming on the show to talk to me about it thanks so much Michael

Channel: Skeptic

Views: 13,754

Keywords: Michael Shermer, Skeptic, big bang, cosmology, epistemology, evolution, laws of nature, multiverse, physics, purpose, quantum physics, relativity, Science Salon, something rather than nothing, Stephen Hawking, The Michael Shermer Show, time, Thomas Hertog

Id: MGzt0Mnvb0k

Length: 84min 55sec (5095 seconds)

Published: Sat Apr 01 2023