Sam Harris & Brian Greene (Audio Fixed)

all right without further ado for the first time ever please welcome to the stage Sam Harris and Brian Greene [Applause] [Music] [Music] I'm pretty sure there was another universe where we didn't almost fall on the stage yeah following victim to gravity so early you know the conversation so thank you all for coming really it's again I've said this at many events but it's it's no less true with this one it's just amazing to put a date on the calendar and show up in a theater and have all of you come out as really it's an immense privilege and thank you [Music] lift weights in order to pour water Bryant Wow thank you so I think we're gonna start kind of a natural place to start is just to talk about what do we think we know and why we think we know it yeah I think a you know from a and then ultimately why any of that matters you know wife being right or wrong or close enough matters for me it's coming from more of a a life science and philosophy of mind background that the thing that that strikes me is the potential hubris of our whole enterprise is that there's a a clear scientific rationale for being skeptical about our powers to know what's going on here and that's if you just take evolution as your starting point there's no reason why apes like ourselves should know a damn thing about what's going on here despite the fact that that our our science and our and the technology that it spawns is incredibly useful and we seem to be playing a language game with ourselves one that's augmented by the language of mathematics that is producing less ignorance and more knowledge if it seems to be pushing back the frontiers of something that is fundamentally the wildering there's a mystery that we confront we don't understand why we get sick and then we discover viruses and bacteria and there seems to be progress right but it's just there there is no reason to expect that the the intuitions we rely on to do science should be fitted to reality in any deep way because if we look at our you know chimpanzee cousins it's obvious not only do they not know a damn thing about what's going on they couldn't possibly know a damn thing about what's going on and we are just a slight iteration beyond them as a matter of just you know Apes to having evolved so where do you as a scientist get your your confidence that the the game you play as a physicist in particular is actually bringing you and other physicists close in into closer context in contact with yeah well I mean I share certainly a lot of that intuition in fact you know had a TV show many many years ago where I was on the first book I wrote and there was one scene where I'm at a blackboard lecture and the general theory of relativity and clearly I'm lucky to a student that's not quite getting it and the camera slowly pans and it's a dog and unfortunately I got so many people the response was they thought I was trying to say the audience was like the dog it wasn't the point the point was exactly one that you're making which is dogs are these intelligent creatures but yet there's a limit to what they can understand and we think that they don't understand for instance the general theory of relativity and every time I say that I always think maybe the dogs are out there that I think we don't understand general relativity but assuming that's not the case here here we have a very good example of smart beings that are limiting what they can understand so why is it that we aren't in the same boat and presumably we are in the same boat so so I think that's a given that we may be limited what we can understand but to the specifics are you question why is it that we think we're making progress it's very straightforward we can sit down with the equations of quantum electrodynamics and calculate properties of electrons their magnetic properties the details don't really matter but the calculation agrees with the measurement decimal by decimal by decimal ten places after the decimal point right that's enough I'm done I mean you know think about that that is an astonishing fact that these strange gloppy things inside of our head can figure out the mathematics to to understand the property of a particle to one part in in a billion and it agrees with measurement and at that point you say to yourself for some reason that we can't quite understand mathematics provides this powerful illumination into the dark qualities of the universe and allows us to make progress on questions that don't seem to have any relevance to survival right but yet somehow the brain has gotten to the point where it can figured these things out and I shouldn't even it's not even not just they don't have relevance to survival one imagines that back on the Savannah those of our forebears who got caught up thinking about black holes and quantum figures I got a yes right you know so it's like not good for us right to do this but yet somehow we're able to yeah well we have did the the last scene that we know about where that was almost certainly true was Archimedes in his bathtub that's a curious point in some more breakthrough in in geometry and then a Roman soldier just came in and impaled him so first rule of self-defense you could stop with the math when someone Kicks down your door so let's just want to revisit some of the points you just made there because they're so people have made I've I've heard I've been a consumer of sceptical utterances on this very topic so yeah it was one popular book on physics I read years ago I think it was probably a John Gribben book and it was he said you know that the this there's there's a famous paper by big neuro I believe the unreasonable effectiveness of mathematics and the Natural Sciences or something close to that yeah and so it's been pitched as this mystery that mathematics is seems to map onto reality in a way that is surprising and counterintuitive and we're still just trying to make sense of that but I think it was Gribben who wrote that actually the the idea that mathematics is it that it's surprising that mathematics maps onto reality it's a little bit like saying it's surprising that the English language is so good for writing plays and right that there's like like this is the thing where we're using and we're finding ways to fit it to the circumstance we're in that is it seems it seems to me that there may be a serious dissing allergy there in that in mathematics unlike English seems to indicate it seems to make predictions about what should be so I mean the relationship between electricity and magnetism say which then can be tested and proven to be true that the mathematics itself sort of shines a light in a direction we weren't necessarily looking right there is that one's that valid but is is there more to it than that I don't think there's more to it than that but that's a breathtaking quality yeah right I mean the fact that you use English to articulate thoughts and describe situations sure that's the mode that we have developed for that kind of communication but mathematics is not a natural language right mathematics is a way that we have found of encapsulating pattern in the world but yet when we have identified the pattern we can then use it to go far beyond the context in which it was developed so you know Einstein is thinking about space and time and and the special theory of relativity 1905 1906 19 then he takes this mathematics off the shelf in about 1912 body of mathematics called Romani and geometry that was largely developed in an abstract realm of mathematics to describe curved shapes the kind of thing that the idle mathematical mind might find interesting but not because we were trying to describe the external world he takes that mathematics is able to work with it into this generalized version of relative of the general theory of relativity and then make predictions about how stars in the distant night sky should look when they're light traverses near the Sun and the way that those positions of the stars shift is then borne out by photographs taken four years later during a solar eclipse when the stars become visible that that's the craziness right he wasn't trying to describe the motion and the positions shifting of those stars and yet he was able to make a statement about something that he had never received any data on and it agreed with subsequent measurements that's the part that is absolutely thrilling so there there are physicists and mathematicians that have a quasi mystical quasi platonic notion about the significance of all those things so so what's your explanation if you have one for why math seems to reach into the darker corners of reality Horace I sort of look at it two ways and it kind of depends on on how a given day is going you know when you're doing the calculations I mean sometimes it feels like you're just sort of chipping away at the stone revealing the beautiful sculpture as if it's already out there and all you're doing is revealing it other days when it's not going so well it just feels like you're desperately trying to invent the idea is in order to be able to make progress so I kind of go back and forth between the two have to say I don't have a consistent view of the role of mathematics in this regard and I would even say there are times when I have I don't know if worried is the right word but I've imagined the possibility that one day we make contact with an alien civilization and they say hey show us what you guys have figured out we bring out the textbooks with all of our beautiful equations and they kind of look at and they go mad they put you in a video where you're the dog yeah right they basically exactly exactly you know they basically say you know we tried that for a while it's kind of a dead end guys it'll take you just so far but then the funny thing is if I try to imagine what they would replace it with I don't even I can't even think of what they would replace it with that isn't in some sense mathematics perhaps in an unrecognizable form or an unfamiliar form perhaps a better way of saying it because if math is a language of pattern what are we doing we're all just trying to encapsulate pattern so whatever language you use to do that maybe that is what math ultimately should be described as and therefore we'll always be back to this kind of structure right there's another physicist so I've spoken with on my podcast a couple of times David Deutsch what I know you know and I forgive me David I forgotten the reason why you believe this but I believe he thinks that we are we're the in principle weak we as math using language forming cognitive systems are not cognitively closed to anything that could be known given I mean I think it has in his mind something to do with with a deep result around information theory and the universality of computation I mean but I don't think I can represent his view faithful here but he then the net result is he thinks that the notion that we could meet an alien intelligence or build a super intelligent computer that we couldn't understand on some level that where we would stand as the dog in relation to that for intelligent system he thinks that's a false fear or just in principle impossible do you have any reason to feel that or I mean I have to understand more fully exactly what it's saying but I mean clearly if you take our very species and you just you know whine the clock back however far you want to go thirty thousand years fifty thousand years seventy thousand years I mean there would be a cognitive mismatch relative to where we are today so it's certainly the case that given enough time we can get to the point obviously here we are but I could certainly imagine that we encounter an alien intelligence and they are exponentially beyond anything that we have understood and therefore we would be like ants and in fact I think that's a good possibility as to why they're not paying attention to us well I think that's part of his argument yeah I actually this takes me exactly where I want to go but I think that is part of his argument that we are given enough time or given enough you know augmentation of ourselves we could fuse our cognitive horizon with anything else that we could meet but on so on that point where the hell is everybody yeah yeah maybe you can remind people what the firming problem is and then tell us what you yeah you know and Enrico Fermi a great physicist is credited with it usually framed as the Fermi paradox I guess which is look there's so many stars out there so many in fact now we know for for a fact that there are so many planetary systems out there therefore you expect there's a lot of life out there where are they well I haven't been coming visit us it's sort of a you know quick way of describing the question and but yeah I think it's an interesting thought to to contemplate I think there are many many explanations for for why they haven't come here it could be like I was saying we're just not interesting enough right I mean how many times do we stop on the street and and have conversations with bacteria right so if we're bacteria you know they're like let's wait you know you know a billion years and maybe at that point we'll pay some attention but there are other explanations too I mean maybe life is rare right I mean we always have this idea in mind I think that at this point life is commonplace well we don't know that or maybe life is come places but intelligent life is rare right I mean if that asteroid hadn't smashed into a 65 million years ago who knows maybe it's still dinosaurs walking around and they're not building radio telescopes and sending out spaceships you know the other possibilities are Legion I mean the universe now 92 billion light years across the observable universe in terms of the things that we've had calls a contact with we have traveled one-and-a-half light seconds from Earth we have sent out probes that have gone out I don't know five or six light hours right so to say why aren't they here the universe is a big place and it's not so easy to travel over large distances if you're constrained by the barrier of the speed of light so what's the what's our farthest impact on the universe just bad television from 70 years ago is that yeah so so if every well seven you know I mean I guess TV you know radio signals go go back to say to 1907 so maybe you know generously 150 light years if you allow you know any transmission that we sent out there so 150 light years compared to you know 92 billion light years right that's not much although I the intuition is that if we go if you look at the fact that we have gone from no barely walking upright to sending out our own space probes in a very short period of time so 300 years of pretty practical science right yeah and if you think of any so I guess the one assumption you need is that there's nothing really special about Earth and more and more it seems that the sense I mean even ten years ago earth seemed more special than it does now now we're finding planets every day that are seemingly in you know some kind of Goldilocks zone with respect to their star and so if you don't think the conditions on earth are so special that they're really a dime a dozen out there in the galaxy and in other galaxies and then you think the just what we're talking about a time window of you know any any place where life gets going and it gets complex is very likely on it could be millions of years on either side of us anything anything is complex that could build a civilization you know is it's not gonna that is very unlikely to have happened in the last 300 years that they might as well have you know three hundred years plus ten million years to have gotten that going right so then you you would expect just the galaxy to be awash in something that we could detect right that has been going on for millions of years I guess the what the with the one additional wrinkle that that we haven't mentioned is that there could just be something about building a complex civilization building technology that is lethal yep species like ourselves absolutely it could be that there were so in every sign of it being being dangerous yeah right right exactly it could be that once you get to the point where you're able to undertake these kind of grand space journeys you're in a very dangerous situation and typically you don't survive there are there are more optimistic ways of explaining it though too so maybe the universe is teeming with all this activity it's just not in the wavelengths that we're looking we're just not sensitive to it right maybe the time scales over which the vibrations of whatever medium that they're using are are incredibly long or incredibly short so we just hear it as like noise in the background and don't recognize that there's a signal or we don't even have any sensitivity to it at all alright so I thought they're bad television is coming a different frequency it could well be right you know so so I don't I don't consider it a paradox I think it's an interesting point of departure and trying to understand whether we're special whether life is special whether their intelligence is special but I mean from your perspective right let's say life is commonplace the journey from life to intelligence is non-trivial do you think that is as straightforward as you might assume in order to come to a conclusion that there should be all sorts of intelligence out there well looking at Earth you wouldn't draw that conclusion why even why do you say that how many species are there on this planet well no I'm saying I'm so I think I'm agreeing with you oh good yeah it's no I mean I'm the truth is I'm even it's non-trivial even if you look at our own species yes that's the point good yeah yeah you know if you murder the top if you Murr if you took of a head so how many people on earth at this moment deeply understand the science required to build intelligent machines right so if they they all call it a bad virus and died off how long would it take just the people left to reinvent the computer right that's it that's a non-trivial problem for most of us if you leave me alone on a desert island with the the necessary elements your suit you're not going to get a an iPhone any time soon and so that either in some sense we're all we're all living on the shoulders of you know if not Giants on the shoulders of legacy institutions and and ways of doing things that it would be very hard for anyone to recapitulate I mean any even any group of especially talented qualified people you know just you just forget how to go you know mind the or that you need to make that in a circuit right so and that's even assuming the existence of us humans already I mean if you just get rid of that whole particular branch then you don't even have anything heading in that dirt yeah yeah so if it strikes me as incredibly tenuous and fragile right so and by no means guaranteed to to keep happening because again and the thing that's that's interesting is that it's an it doesn't what what we are using to do everything that makes us human is not obviously better from a Darwinian perspective as a matter of survival I mean cuz you know again in the long run we could wind up killing ourselves and there are many things that have persisted as themselves as you know as discrete species for tens of millions of years you know you take something like a lobster right now lobsters are just doing their lobster thing year after year after year and they seem to be fine unless we wind up you know eating too many of them are destroying their environment we that there's something quite a bit more precarious about that our place in the world and yeah so it's not even just as a mat on purely Darwinian grounds it's not like this surfeit of intelligence and abstract thought is it's clearly something that evolution is an attractor that evolution will keep finding because it's it's just so good for right out of survival right no I agree and I think that's a very natural explanation not most optimist ones but certainly is an explanation well I'm rarely accused of optimism so so he optimistically asks what worries you at this moment in human history when you look at how we as a species think about reality and how to live within it what do you I you know you and I don't know each other well at all I don't know or do you pay attention to things in the culture even relevant to your science like a bit is the fact that nuclear proliferation the prospect of nuclear war either by design or by accident you the fact that's almost not talked about it all now and yet every moment of our lives we've been living under this same sword of Damocles is that something that you spend time thinking about or you know no no well no there's reason it's an honest answer if it's true but are you are you not part of any meetings of physicists that that worry about that you know so so but the truth is that the horror is that it's actually true right for most of us I mean like we have gone to sleep on this issue well I would say that that is a reasonable description of me I mean I'm obviously we all are aware of these issues I think about these issues i I don't from a day-to-day perspective worry about these issues nor from a day-to-day perspective do I work on these issues and it could well be that we have lulled ourselves into a state of complacency by virtue of nothing you know catastrophic you know happening yesterday or the day before I do you know walk around the world with an optimistic sensibility you know that we will find ways to deal with these issues but that can be a masquerade for an unfortunate complacency at the same time so what what are the if you could list the problems that you felt we needed to address and we could if we can get our priorities straight what's near the top of your list in terms of well they were the obvious ones that we would all I think put their you know we can rattle them off you started with nuclear proliferation issues of clean energy issues of environmental catastrophe ones you know that we just you know we were briefly touching upon you know we had dinner just a couple hours ago issues of you know AI which I would even frame in a you know in a some more general paradigm which is I don't think we're very good at having the intuition about exponential growth yeah it's just not something that we're really good at I mean you know everybody this is a self-selected audience but anybody who has never heard of you know the standard example where you know you get a penny on the first day and two pennies on the second and four on the third and so you know anybody who hasn't heard that before and learns that by the end of the month you've got a billion dollars plus they're like what you know everybody here knows that but everybody who's not seen that before it's very surprising so I think the scariest things are those which have an exponential growth and we're not paying attention to them sufficiently early and we get whacked by the exponential growth of some quality of the world that needs our attention and we didn't give it attention early enough in the process and I think you know AI is a possibility along those loans you know so you don't take the notion of an intelligence explosion or a some kind of singularity some kind of break away of AI you take that seriously you know I I would say I take it seriously it's not something that I that I fear I don't deeply fear it and again I question my own self about that should I be fearing it more and if I ask myself why I don't it's because I think fundamentally fundamentally I think that the people who are responsible for the innovation that for instance may yield you know an intelligence that at some point may far outstrip us it feels too that the people leading the charge on that are fundamentally good people I know these people some of you know I just feel that they're good people and that ultimately they will pay attention to the safety issues that need to be thought through now on their 12th red bull it could be it could be you know and and and you know we have examples in the past where we thought doomsday was upon us you know you know nuclear weapons you know I mean they're they're moments where it looked like we were at the precipice and we've found a way to survive and I guess that has given me an optimistic Sensibility it's been challenged you know November 8th 2016 it was challenged it continues to be challenged you know but but I think fundamentally I'm still in the same place right well you're you're in New Yorker you'll be fine right yeah well so I will not take the the orange bait there so well but to speak generically about politics and kind of culture war issue so you I think you and I take a different line here so I've spent a lot of time arguing mcli about the the there's there being a kind of zero-sum contest between religion and science right or believing things for good reasons and believing things for bad reasons or flip that around yeah and you have you haven't I think you've been loath to hit them against one another in a way that will reliably turn people off to scientific ant have their resurrection and their cosmology to a significant number of Americans will say well okay your cosmology I stick with Jesus and you know obviously you're not alone in that but so that one image you acknowledge that that's a difference between the way we have kind of played the game actually I think so it'd be good to you know if that's something you want to probably should you know expand on that somewhat but but I think that's the case and you know my feeling from the outside watching and I don't even mean to put you in this group with them this may not be accurate but I've certainly seen certain members of the science community going out into the world in a way that I consider ineffective toward their own stated goal and that feels irrational to me you know to go out into the world and tell people that you're stupid for certain kinds of beliefs strikes me as not the best strategy right I mean you know the strategy that I feel works is to go out into the world with a passion and enthusiasm for the things that you think are good to understand and important to understand and point in a in a valuable direction and to hope that the energy and the momentum from those kinds of conversations will drive things in a good direction I've never felt the need to go out into the world and slap down other things that's now how I want to spend my time and I've never found that an effective approach yeah well I totally understand that I think there are some so having taken the other line and and now I have I have a fair amount of experience with this I can tell you that there there are a few myths here that that could could be and perhaps should be retired one is the idea that that it simply never works right that you can never reason someone out of something they weren't reasoned into you know so someone you know was born to a faith they've had it drummed into them by their parents they're now massively attached to it emotionally yeah they get they they get to adulthood it's still the most important thing in their life they've taught their children to believe likewise there's you can't tell you can't reason that person out of these this set of convictions that's just untrue because I hear from these people all the time who have watched some debate or watched some video no matter how offensive at first glance that they're susceptible to just seen the the bad evidence and the bad arguments that have been propping up their faith you know lo these many millennia but not to interrupt let me just quickly say that I agree with the capacity to shift people's attitudes perspectives beliefs but as I've had those experiences too but I've done it a different way and when I've gotten people coming up to me or writing the email saying you know now that I understand the fundamental workings of the universe a little bit better and understand the cosmology that the other person might have pushed off but now that I have an understanding of what modern science is saying about these things I just find it thrilling and the other things that used to find and find gratify no longer working for me well I've seen that too right no but that but that's you're talking about the carrot I'm still talking about the stick on some yes I agree so but again I'm saying the stick also works you know so and but I guess what I've say to you is if the stick works and the Carol's first I think they're probably working on different people let's put that to the side for the moment which would you rather use I found and I'm saying I found you can only hit someone so hard with a carrot and a knife at you don't need to hit them at all well so but I should just say so for instance just to kind of prep you for your I think did I think Travis just announced that you're doing an event with Dawkins right yes okay so I'm preparing you for your much appreciated but I've had conversations in a public setting them before but that's okay yeah no but I heard I heard his I heard him over my shoulder when you were talking about the generic offensive atheist who wasn't necessarily me it might have been Richard but I'm just saying I'm sure he's sitting on tens of thousands of emails from people who can honestly say you know though I thought you were an offensive bastard at the beginning you actually argued me out of my most cherished beliefs so that I'm just saying that's a matter of sociology that happens right now but yet it's counter to it we all know that there is this phenomenon of a that we it's actually been been now studied up to a point this notion of a backfire effect where you when you challenge people's beliefs and you even when you when you provide them with counter evidence to those beliefs they there's some part of the human nervous system that just doubles down in the face of counter evidence and they leave this confrontation believing what they believe even more ardently than they did in the first place so that happens but I guess it's I mean if in part it's a matter of taste it's certainly a matter of just how you want to spend your time I completely get that you don't want to be the guy who is just the go-to guy for you know why you can't have your your cake and eat it too in the matter of science versus religion but have you ever found yourself on specific issues where the method to take one so we were just talking about the environment and a nuclear the prospect of nuclear war there are religious ideas that seemingly perfectly inoculate people against viewing those as problems there's no there's no degree to which we could despoil the environment and there's no threat of nuclear Cataclysm so salient they could get a fundamentalist Christian say who's waiting for Jesus to return and hurl sinners into a lake of fire to really worry about those problems because on some level those are the things that have to happen as precursors to the the glorious end of the world and if it's it's just as a matter of Biblical prophecy you can just connect the dots and the things really do have to go to hell in a handbasket in order for the best thing that's ever going to happen to finally happen so those are that all the signs and and and wonders that they're waiting to see right so if you find yourself in the presence of that kind of dogmatism where the worse things get really the better they're getting right because Jesus is going to come back and solve all our problems don't you feel as I just as a don't you feel like in an intellectual and or ethical responsibility as a scientist to push hard on the specific beliefs that stand in the way of thinking rationally about those problem yeah you know it's a good question in fact it's one that that I have had that conversation with Richard and we came to an interesting point which is I'm rarely confronted with the situation that you described and we suspect at least emerge from our conversation because there's more of a focus if you will on the biological sciences as the place where a fundamentalist religious perspective will look for a point of confrontation revolutionary yeah then with you know somebody who's talking about vibrating strings and extra dimensions and the kind of abstract science that I focus my research attention on so I'm not in that situation I'm rarely in fact I don't think I'm ever in that situation and that may if I were on a regular base at EU and thank you to a couple of parties yeah right exactly you know you know well so okay so back to your areas areas of controversy in your world it's just as a consumer of physics from the outside it seems like many people are worried that a really at physics as a discipline has been more or less moribund for a generation that you had you have string theory that this is like the most celebrated thing in the was the most celebrated thing at a certain point but everyone was sort of just waiting around for it to deliver the goods and it hasn't yet and you have a whole generation of physicists that got absorbed by this this what was a kind of intellectual fashion in in theoretical physics which may not have panned out and may never pan out now this is again these are the echoes of yeah rental graduate students that that one here is what what's your view of the state of physics yeah well you know I think what you're describing is something that the press has picked up on in various times and it certainly has echoed in a certain way throughout the public and throughout the press and so on but the fact of the matter is that physics is in a theoretical physics in a very healthy state in that there are a lot of great ideas and there's a lot of substantial progress and when one says that a theory like string theory has not delivered the goods it feels odd for me to hear that I understand where you're coming from but it strikes me that it's coming from a place where you've not been with in the field sufficiently deep to really see the progress that has been made I'm in theory on paper puts together gravity and quantum mechanics the fundamental theoretical problem of 20th century physics and principle has the solution within string theory is it the right solution we don't know that's a great progress but then why is it why is it controversial why isn't everyone a string theorist if that if that marriage has been consummated they're just not good no no it's a get it get it on Twitter we want to know the answer the answer to that question and and please don't tweet that was just the answer to that question is that it's extraordinarily difficult to test any theory that puts gravity and quantum mechanics together extraordinary difficult because we don't have the technological feasibility to test it theory in the domains where it differentiates itself from conventional theories and this is not just an issue that faces string theory any theory that puts gravity and quantum mechanics together is going to face this dilemma so if we were able to build an accelerator as big as the galaxy then we'd be able to test these ideas that's tough to do in this funding environment you know so that's really the issue the issue is that on paper there are features of the theory that are enormous ly attractive but we can't test them moreover theorists like myself will also point out the theory itself has gone into some directions that raise questions interesting questions a theory that predicts other universes as a possible intrinsic quality of the theory you got to take a step back and ask yourself does that make logical sense is that a theory that we're willing to take seriously and you know after studying these questions intently for a long period of time my answer is that yes these are worthy of our attention that these theories may be taking us into the right direction do we know that they're right no the only thing we'll ever establish it there correct and end the controversy would be to make a prediction and we go out and measure it and that is the gold standard and that's something that we've not been able to achieve the theory is in many ways in its early stages even 3040 years later these are difficult questions so that's the answer why it's controversial it's not made a testable prediction but the theory continues to make substantial progress on understand the nature of space and time the nature of black holes the theories been able to embrace effectively all of the discoveries of the past all of them naturally fit within the structure strengths you don't have to wipe out the past and embraces the past these qualities make the theory enormous ly attractive and compelling again it's not yet been tested so it hasn't made any prediction analogous to the kinds that that Einstein's relativity made that were not a matter of of having to build some apparatus with insane energies but just you know looking up it at the bending of starlight that has there been anything like that with string theory that has absolutely not and that's I mean you know it's funny I you that you bring that up you know I had a high school student many years ago who did a Science Talent Search project in his competition United States where they calculated this woman calculated the corrections to the bending of starlight by the Sun that come out of string theory like so that's what Einstein did and maybe string theory modifies the prediction and and you know it was a thought experiment i roughly knew what the answer would be and the answer that she got from calculation turned out to be about the same it was about one part in like 10 to the 90 yeah that's that's hard so yes so you know it's a it's it's something that you're not going to be able to measure it's too small yeah aren't there fewer 10 to the 88th yeah if you're a particle universityõs right so so we mentioned multiple universes I think they're they're meant there at least a few different ways in which there might be multiple universe the there is a many-worlds interpretation of quantum mechanics that I think to the I think to the alarm of most people who hear about this is very well subscribed among physicists right now where you come out you might want to summarize what why one would be tempted to believe in in multiple universes but these are these are universes where in you know trillions upon trillions of nearly identical copies of ourselves are having nearly identical conversations you know just but but with every different variation of what's possible essentially everything that can possibly happen happen somewhere so there was there was that's compatible with the laws of physics yeah so there was there is a universe if you subscribe to this theory there is a universe in which we had this conversation and then you know took our clothes off in the middle of it right for reasons that presumably made sense in that unit wait let me calculate not compatible the laws of physics right yeah guess this will not happen in this universe rest assured but this is this is actually believed right now this this on its face to me is the least believable thing on offer yeah and yet this is this is not only yeah subscribe but to buy someone this is this is actually just plain vanila quantum mechanics now I I wouldn't go that far new but I think like great controversy on this I mean David Deutsch who mentioned is one of our opponents of this way of thinking about quantum mechanics but I would not call it the vanilla interpretation of quantum mechanics I think if you pull people at a physics conference you get something change 30% or something that they believe that I don't know if 30% I would call vanilla but you know it changes over time and and I first maybe it's worth quickly saying what it is and then I can give you my perspective on it so so so quantum mechanics broke with the past by saying that whereas Newton in classical physics taught us that you can given the state of the world now predict how it will be five minutes later or million years later using the equations of motion to evolve it forward in time quantum theory came along and said that's the wrong way of thinking about things if you know everything that you can know about the universe right now the best you can do is predict the probability the likelihood that you get one or another outcome when you run the equations forward an hour or 100 million years into the future now that sets up an interesting situation because for instance if the law says that there's a 50% chance that the electron is here and 50% chance that it's over here right when you go to measure the electron you don't find sort of half of it here and half of it here you always find one whole electron either here or here so the question is if you find the electron in my left hand what happened to the possibility of it being in my right hand you might say well that just goes away the problem is just goes away is incompatible with the mathematics the most straightforward reading of the equation suggests if you just use the most straightforward interpretation that's right there the equation suggests that there's actually one universe where indeed you do find it in my left hand and there's another universe where you find it in my right hand and therefore there's a copy of me in that universe with two hands thinking that there's only one unique outcome but they're two of me and distinct universes own to that same illusion that there's only one universe but the gods I view if you don't mind me using that metaphor is that there are there are there are there there are many universes out there and basically anything that's allowed by the laws of quantum physics is represented in this menagerie of universes now if you ask me do I subscribe to this way of thinking about quantum mechanics my answer is no and the reason is I'm not saying that it's wrong I'm saying that we're not at the point yet where we can answer that question because there's a gaping hole in the structure of quantum mechanics that maybe doesn't get enough air time quantum mechanics in my view and many others but this is not Universal is not a complete subject we're missing a solution to the so-called quantum measurement problem which simply is the question when you measure the of a particle like an electron how do you go from this weird fuzzy mixture of multiple possibilities it's over here and it's over here and there's some kind of fuzzy mixture of the two how do you go from that fuzzy probabilistic description in the equations to the single definite reality that emerges when you actually undertake the observation how do you go from fuzziness to definite reality and this is a question that we do not know the answer to and since clearly and thinking about where the possibilities go the act of measurement or observation is intrinsic to the very question that we're talking about until we answer that question we can't really come to a conclusion on what the right way of thinking about quantum mechanics is do you think we're far enough along that we can conclude that there is no answer that goes down easily with respect to our intuitions that know that any answer is going to seem crazy no I don't think so okay there is a version of quantum mechanics that's sort of the Dark Horse version of the theory due to someone named David Bohm also Louie Dubrow had the same idea a couple decades earlier and this version of quantum mechanics that's virtually never taught never spoken about in public has the quality that particles still go along trajectories right the the new idea of quantum mechanics says in the traditional way that one talks about is particles don't move on trajectories just those nebulous waves that are evolving in some weird quantum space called Hilbert space not even the space that we live in that's the reality that's being described by the equations but David David Bohm came along and said no there's a version of this theory in which particles still go along definite trajectories and and that's closer to our intuition about how the world works so this way of thinking about quantum mechanics were to bear fruit if that's the right way of doing it it will be somewhat closer to our intuition then the version that we currently talk about remind me what what do you I still recall you have to sacrifice something that were attached to as a matter of common sense with Boehm if to sacrifice locality right it's a non-local that's right so so it has the weird property that you know you do something over here and it affects something over here instantaneously and over here it can be an end romp would be in the other side of the universe now you say as you rightly do we're giving something up and therefore that suggests that there are other versions of quantum mechanics where you don't have to give that up but the fact of the matter is even in the most straightforward version of quantum mechanics that we teach to our students all the time there is a non-local quality already it's called entanglement yeah it's the einstein-podolsky-rosen contribution in 1935 which showed that if you have a particle over here and a particle over here you do a measurement over here measurement right so again this unknown quality called quantum measurement comes into the story but you do a measurement over here and it affects the particle over here this is what Einstein called spooky spooky action at a distance you do something here and it affects something over there but that's within the standard formulation of quantum mechanics as well in this balmy inversion it's made more explicit it's more in-your-face right it's right there in the math you don't have to do analysis to find it but in a sense you're not giving something up because you've already given it up with quantum mechanics now it's very fashionable in new-age circles to find solace in one interpretation of quantum mechanics which is usually described as the Copenhagen interpretation which privileges this measurement moment of the the the role of consciousness in determining the nature of reality and Einstein famously said you know do you really think that the moon doesn't exist unless I'm looking at it as a way of disparaging this this view my sense from talking to physicists of late is that that interpretations of QM that privileged the role of consciousness are less and less fashionable to the point of being more or less retired now is that that actually we're where it is and and do you what do you think about consciousness as as a part of this puzzle well it's it's a very hard question because you can't ever get out of your head right I mean if you imagine a measurement being undertaken not by a conscious being but by a computer or some mechanical device you'd say well there's no conscious quality involved and therefore consciousness can't play a role in the process you still need to go over and look at the device to see whether it's accomplished what you set it out to do so it's very hard to ever get outside of the framework in which a conscious being is brought in at some point in the quantum mechanical story and that's what makes it hard to excise it fully however having said that it there's no reason that we can possibly see where consciousness plays a fundamental role in the quantum unfolding right I mean you write down the basic equations and they apply to individual particles and whether those individual particles are grouped together in some amorphous mass or into this nicely organized structure that allows some kind of internal processing to take place it doesn't seem to matter to the equations that's an add-on and therefore it doesn't seem that consciousness is is vital to the story so I don't think so I don't think consciousness is essential and I would just underscore one point we talk about interpretations of quantum mechanics as if quantum mechanics exists and we're just sort of sitting back trying to say what do we make of it that's not the situation yeah these so-called different interpretations are attempting to resolve this unsolved problem of quantum measurement and that's a real issue and therefore it can well be the case that these aren't just different interpretations they're different theories and if we understand them well enough when we finally have a solution to the measurement problem we might find that it's not that though we were struggling with interpretations we were struggling with actually giving birth to the full theory itself and I suspect that that's where things will ultimately turn out right right well I know we have to go to questions soon I just have one more question I want to ask you before we do but perhaps if that needs to be prepared at any way with mics we should do that but what is the status of the the concept of time in physics now as we you know most of us know that space and time got married with with Einstein and so you we speak of space-time as opposed to time on its own but every time at time is a both space and time our intuitions we have I mean they're they're kind of proof our nervous system is sectioning reality in such a way as to naturally produce these concepts for us and there's every reason to believe now it sounds that like that our common sense about space and time is not in fact what they are as a matter of physical reality but there are concepts in physics like the concept of a block universe right would that suggest that we're we're radically at odds with with what reality is that under some control the future exists just as much as as the present and the patent that as does the past and so what can you give us a kind of a potted view of what time is from the point of view of physics today and and as a matter of time you have two minutes so before Einstein came on the scene everybody had the intuitive notion of time and that was the very notion of time that was in the equations of physics that that Newton gave us and when Einstein came along he shattered that perspective first in 1905 I think as many are familiar by showing that objects in motion will find that their clocks do not take time at the same rate right that's crazy right we used to think there is a time that we're all relentlessly moving forward within second after second and if you're in relative motion your clocks won't take off time at the same rate that's crazy then and that's been also experimentally established that's not just a matter of a theory we've sent clocks around the world and airplanes and and our GPS relies on taking that into account and all that absolutely right we've got particles and accelerators that are living much longer than they would if they were sitting on a table because their clock is taking off time more slowly so this is beyond doubt then 1915 Einstein gives us general relativity and we learned that it's not just motion that affects the passage of time it's also gravity effects the passage of time so if you're near a strong gravitational source time will tick off far more slowly than it is if you're far away from that gravitational source that gravitational potential again that's kind of a crazy idea right you hang out near the edge of a black hole and time for your laps is more slowly than for somebody who is far away now these are all giving us insights into strange and unexpected features about the nature of time and also space which is melded together as you indicated but the deeper question is the one that you asked toward the end which is is time and space are these fundamental structures in reality or do we impose them on reality in order to organize our inner perception and it's a very hard question I don't know the answer to it but I will say this one of the features of string theory in the last few years some really remarkable work has gone a really giant step forward towards showing that space and time may not be fundamental structures they may emerge from more basic ingredients that naturally arise in string theory so you know this is emergence of course is a familiar idea in many subjects you know we all know what temperature means you know when things are hot when they're cold but then you dig and we know the temperature actually is a reflection of how quickly molecules and atoms are moving something is hot when the average motion is fast something's cold when the average motion is slower so that gives us a deeper understanding of what temperature is in terms of more fundamental entities yeah we've now taken a step toward that kind of progression for space and time there's work in string theory that shows that space may actually be stitched together by the threads of the quantum entanglement that we were describing before that non-local quality of quantum mechanics we've been able to do calculations within string theory in essence where we're able to cut the threads that are keeping the fabric of space together nothing to worry about it's just mathematics but you know we cut these threads and we're able to see that what remains are sort of isolated points that no longer stitch together in the manner of our familiar conception of what space is so this to me is is probably the next revolution if you ask me what the next revolution is it's going to be a way of thinking about physics in which space and time are not put in at the get-go into the equations but rather emerge later on when certain environmental conditions are met and when they are met space and time as we intuitively know them will emerge but when those conditions are not met there can be realms of the universe in which there is no conventional notion of space and no conventional notion of time right well unfortunately on this stage there's a very conventional notion of time so we would love to get your questions and we'd love the house lights to change those that we can see some of you and we will just go left and right here start over here yes and just just to remind everybody questions questions often end in a high rising tone so if you can achieve that you're you're good thank you you I found it very interesting and thank you to you both for coming to Toronto [Music] my question kind of loosely relates to kind of what you guys talked about in the beginning and there was a scientist Sam you talked about who you said you don't know why he came to this conclusion but there was a yeah there's no way to conceivably think of AI or an alien species that humans can't comprehend my question kind of loosely relates to that and I kind of have to preface it with a quick explanation of experiments how I think about in my head I don't really know what the experiments called was like the red dot experiment words excitement issed would put a red dot on different animals forehead yeah hood Amir yes self recognition yes then kind of rank their level of intelligence or their level of capacity of consciousness yeah I was wondering if maybe both of you have an opinion on this whether humans kind of have an analogous kind of red dot point where there becomes a problem or an issue where just our biology or our capacity of knowledge or consciousness you know we might look at the answer of the problem right in the face and just not be able to see it like it's right there but yeah just can't comprehend to áthen our um so I guess for both of you kind of is appropriate because Sam your deep your primary concern is consciousness and uh both thought and Brian I assume that you and your colleagues are probably gonna be at the forefront butting heads with these problems so I guess my question is do you guys think that there's a limit or can humans just continually expand yeah it's an interesting analogy that I haven't really thought of before but so so just to remind you all what that is that there's this mirror self recognition that has been done on various species of animals and most species no matter how smart they appear in other ways if you put them in front of a mirror they don't warm up to the realization that that's them in the glass they relate to that that other species as a that image as another member of their species so and embarrassment ensues but there are certain species that that very few that can gradually recognize that that you know the based on their own movements that that you know that the dot is on their heads and I think we are I was so just it's very easy to see personally I mean I think you cease to see that one as an individual has certain limitations certain things to which one is is cognitively and emotionally and just dispositional II closed right at certain games you can't play or you certainly can't play in any under any kind of time horizon that make get pragmatic for you to attempt to play those games right so like you put put in a room with the the Martians for law like how long does the conversation have to go on to fully explore your cognitive limits well you know for many of us not all that long right and then the question is how you know I but it my sense is that but this is another question I could ask you to that's fits in here if you could nominate one member of our species past or present who just as a as a brain that would be best suited to to explore the limits of human cognitive horizons in the presence of super intelligent aliens who would you would you put in that room to just say okay this is humanity this is the best we've got in terms of dialogue with this piece I know Justin Bieber it you know III don't know and I think part of the answer to that question but let me just give you a candidate so it's either john von neumann or it's Isaac Newton yeah you can you can give them all the modern understanding of just like oh just a brain to just just put there I guess I would be uncomfortable because they're really smart at certain things yeah but like why not Shakespeare or Freud yeah I mean there's just so many different ways of thinking are you really why not Freud but I stop myself halfway but interesting you knew where I was going there so you know I think intelligence comes in a wide variety different forms and it could be as you're suggesting that the answers right in front of us and we don't see it I suspect that's a real possibility but I'll give you one data point and I'm not sure how relevant it is but at least it gives me some sense of optimism when I was a graduate student a long time ago it seemed like the amount of material that you needed to learn in order to even begin to do your research for the degree the doctoral degree was like incredible right I mean so how do you gonna study all this and then have time left do the project but yet somehow we're able to do it and now you know 35 years later whatever it is with all of the progress that's been made I mean the kids that come into string theory they have to learn everything that I had to learn back then and they have to learn the past 35 years of it too and yet they still have to be done in the same number of years and somehow they're able to do it so so it feels to me that I still have Instagram accounts to attend to it that that's the amazing thing and Fortnight you know they still play it for at night you know so so it strikes me that there's some way that we're able to adapt to the ever greater volume of information and knowledge that we need in order to make progress so I guess what I'm saying is the fact that we've not hit that wall gives me hope that we're pretty good we're pretty flexible but could it be logically speaking that there is a wall and all that we're looking for is just an inch beyond that wall and we can't quite see through it yeah that was kind of more what I was not necessarily an individual single human that represents the best but more like you know 200 years ago in terms of evolutionary time we're pretty much the same but drastically different like will that just continue well we eventually be the green headed aliens coming down with super magical technology or we get to a point where as long as we keep going I think it's the leverage is in culture I mean we keep we keep porting are not all the gains into culture and then there's a kind of a chunky and I mean this explains how each new wave of graduate students can how to recapitulate the history of intellectual progress in physics in their own lifetime and you know know more about physics that Einstein did and then and then keep going it's anyway interesting question over here you're probably both aware of Niels Bohr's position physics is to be regarded not so much as the study of something a priori given but rather as a development of methods of ordering and surveying human experience so it's less finding the photon that's actually there and more making sense of those lines as a picture of an old woman or a young woman yeah what's what's your take on onboards position well I think we actually in deference the time I'll say we sort of covered that in talking about the Copenhagen interpretation of physics and they was he was the the originator of that interpretation and you know that the sense at that point when when quantum mechanics was first being born there was a very strong sense that the universe was more mind like than matter like based on that view of things and feel free to correct me if I'm wrong here but I feel like the conversation that very least has widened and moved on and it were not quite there with Bohr's take on it yeah the one thing I would add to that is you know board Bohr had a of the world which is aligning with what you're saying is ultimately science is about explaining observations and data it's not about peeling back the curtain and seeing the fundamental reality and I think Bohr was forced into that position by virtue of the fact that he couldn't peel back the curtain and quantum mechanics was working and yet he was unable to tell us what it was telling us about the true nature of reality so he said don't worry about the true nature that's not what physics is about and I think it's a very limited way of looking at science I'm not so interested in being able to only predict the results of experiments I like that that's the gold standard but in the end of the day when I'm on my deathbed I hope that I have some deeper understanding of what's reality of what's behind that curtain and if all that we're doing is being better able at predicting results of experiments to further decimal places down the line I'd rather be doing something else over here I thank you both for coming my question is for Sam earlier in the talk you asked dr. green about what issues keep him up at night and aside from nuclear proliferation I was wondering if you could share with us your answer for the same well largely it is that the meta issue of our reliable failure to make sense to one another and have conversations that productively that lead to the solution of problems in any kind of direct way you know so the fact that we have political systems that can't function over a long time horizon you know we've got this a four year election cycle presidentially to worry about and therefore it's impossible to have a a forty year plan about anything right and and we have we have we have problems whose time horizon is long or long ish and we have we have problems that are global in nature so they by definition we can't solve these individually as nation states and we can't solve these by fixating on the the incentives of a you know a four-year election cycle and in the midst of all that we have a level of polarization whether it's you know political or or its ideological across the board it's it's religious it's I mean there are many things that contaminate our conversation with one another which make it impossible to make sense long enough and and productively enough to get all of us to converge on even just even to recognize what the problems are much less how to solve them so I just think that the I think conversation is all we have successful conversation is all we have to solve our problems together and when I see it just break down not only frequently and catastrophic Lee but reliably so it's like you can see you can just guarantee that the conversation is going to be ineffectual given where most people are most of the time that that's that's what worries me and that's kind of the meta problem that that subsumes all the others whether its climate change or nuclear or proliferation or how do we deal how do we deal with emerging pandemics or the prospect thereof you know why can't we decide to make more antibiotics that when we know we're running out of them we just can't agree how to create systems that that incentivize things we know we want to do or should know we want to do because we we can't even we can't even talk coherently enough about this thing so hi so Sam's opening question for dr. Greene was what is it that gives you optimism about that one can make progress I guess intellectually and your answer was that we can improve the outcomes or we could predict the outcomes of experiments even the most recent question you actually said if that's all we're doing you'd rather find something else to do and during your talk you said that the quantum measurement problem is the gaping hole in the quantum quantum theory of quantum theories or a theory of quantum mechanics and makes it almost impossible to choose between those that emerge and so it seems that there's no path to a place where the thing that you that gives you confidence that we can make progress no path exists to that state do you retain confidence in the endeavor you know I've never quite thought of it that way and I'm kind of devastated ya know so a few things first off when I talk about what gives me confidence in the approach that we're following it's the fact that we have a powerful diagnostic that tells us whether we're going in the right direction that diagnostic is not the final reason we do what we do but that diagnostic is can you make a prediction can you test it with an observation or an experiment and I love it as a diagnostic I don't love it as the end game and that's the difference between the two now in terms of the the quantum measurement problem itself it's a very curious state of affairs because we have an algorithm called a quantum algorithm that allows us to make predictions for the result of an experiment even though the intermediate step we don't understand how the universe makes that intermediate step and that's the hole that I was describing earlier but nevertheless the algorithm works and that's borne out by the agreement between prediction and observations so it's not as though we're we're fully at sea and the boats about to tip we are incredibly on course but there are vital pieces of the story that we've yet to figure out now I should say there are other physicists who would be up here and saying there is no quantum measurement problem I mean my good friend you know Anton Zeilinger you know this is a this is a brilliant man who doesn't just do quantum physics calculations he actually does the experiment so this is like the real deal not like someone just spouts off about these ideas he actually does the stuff and you know when I sit with him and talk with him he kind of has an avuncular attitude toward me he says hey you can worry about those kind of things if you want to put you're wasting your time because there's no problem Brian and and and so that's his perspective it works we have an algorithm and we can make predictions and end of story so so it's just to say that their different attitudes as to whether this is an issue because I think there are different goals that we have a scientists as we're saying to the earlier question some of us just want to be able to predict some of us want to be able to enlighten and whether that latter goal is misguided I don't know I don't think it is but some in the field certainly do hello my name is Brendan I'm an intern on some of the dark matter experiments at snow lab and I have a question for Brian I was curious seeing the results from many recent dark matter of experiments that have searched larger energy spaces and are possibly indicating it may not exist and that brings into question some of the predictions of super century so I was wondering what do you think the plan B is if that doesn't work out well just 30 seconds on the background and everybody I think knows that since the 1930s has been increasing evidence that there should be more stuff out there than we see dark stuff because we need something to give rise to an additional gravitational tug responsible for the motions of stars and galaxies that we observe so for a long time now we've been trying to go out and find this dark stuff we assume that it's raining down on earth we don't see it but we build detectors in hopes that we will can you spell out what dark means in this context the dark so Li means that it doesn't give off light and that's really all that it is so it's many of the proposals involve particles that as the questioner asked some of them are exotic species of particles that come out of theories like string theory or more generally supersymmetry and we had hoped and the hope is not dead that these experiments would capture one of these dark particles particles that don't give off light that don't interact with the electromagnetic force that's not a more precise way of saying it but we've come up empty-handed for a long time so what's the answer to this there are a number of answers number one it could be that we just got to keep on looking and we'll find it I think that's the the bread but 'ran to that many people still have more exotic answer is that perhaps there is no dark matter at all and maybe it's our understanding of the force of gravity that needs to be modified and that's why things are moving in a way that doesn't comport with our previous understanding of gravity and that motivated the introduction of this new stuff to make up the difference but maybe it's gravity that's not doing what we think it should be doing and the third possibility which is a lab eration of that is there are exotic ideas that have emerged from string theory so-called holographic ideas be a bit involved to explain it in any detail but some of those ideas suggest that there's no need for dark matter at all that the natural solution to the mismatch between observation and prediction is resolved in these more exotic approaches to understanding the force of gravity so those are two and a half roughly three possible plan B's [Music] hi there I'm glad and this question is for Sam but I'd love to hear Brian's thoughts as well Sam you see our efforts to make moral progress as US navigating landscape of possible states of consciousness and the way to navigate that space is through science I generally agree with this but I think that there are certain categories of navigation problems to which science cannot provide an objective answer due to the fact that there are any types of beneficial mental states that are qualitatively different from each other and not readily comparable so for example loving another person or the joy of working to create something or mindfulness helping others etc right and it may be the case that achieving a peak in one area let's say intense meditation or mindfulness may necessitate suffering in another area let's say the love that comes from close personal relationships so my question is how can we ever determine which is more important how can science help us navigate when realizing one beneficial conscious state is in conflict with realizing another beneficial but qualitatively different precious state and you want me to weigh in on this too you can say as much as I said about dark matter [Laughter] well so just a couple of intuitions there that I would just want to push on one is the idea that not being able to answer those questions is a problem for the for the claim that there is an answer to those questions so this is in my book the moral landscape I differentiated answers in practice from answers in principle we know there are there are many facts of the matter for which there there are answers in principle and trivially easy answers in principle integer based answers you know like how many grains of sand are there on earth right you know as long as we define grain of sand clearly enough you know that is an integer answer and yet we know we'll never have access to information and it probably just changed anyway right so you know or even simpler you know how many the example I've often used is you know how many birds are in flight over the surface of the earth at this moment right well it just changed and we know we're never gonna get the data so but there was there was an answer to that question there are other kinds of questions where there there are no clear answers but there's there are ranges of answers there's kind of a blurry you know haze around the right answer and it's and some of these are just norms of you just how we run society it's like what's the right age to give someone a driver's license well you know when I was fifteen and a half I thought you know 16 was was probably a little too late now when I Drive and I look over and I see a 16 year old behind the wheel of a 4,000 pound automobile I think that looks insane to me right so if self-driving cars can't come soon enough but but what is that what's the right answer well given all things consider like so and it's so it's an all things considered situation where we know we can never do this perfectly we know that some 16 year-olds are really not up to it but we have to draw the line somewhere wherever we draw the line it's going to be arbitrary 16's arbitrary 16 and 1/2 is arbitrary 18 would be arbitrary and yet and there and yet it's we know there are wrong answers we know that six months is definitely the wrong answer right so if you shift the window of consideration there so you're just you're not capturing anything we care about if you move it to 16 well you're you know not if we moved it to 25 you know fewer people would die there's no question right but we have other concerns beyond body count we have you know mothers and fathers who are just sick of driving their kids to school every day right so what's that worth and we play around with this and we know we're never going to do the math sufficiently so that we know to you know down to our toes that we've got it perfectly right right but it doesn't mean that there aren't better and worse answers in that space we know there are worse answers you know six months you just gets you absolutely nowhere and a hundred also that doesn't work right so the answer is somewhere along this continuum and for many things in life we have to be satisfied with that now I think well we will be less and less satisfied the more we can get our hands on really good data and the more our technology allows us to to use that data in ways and I think that and I think this will be surprising so I may just this is this is true in medicine in many ways it's like like when there's nothing to do about a condition right there is no cure there's no understanding of its basic biology and yet people are suffering mightily you know it's like polio right people are it was it used to be a common feature of life even in the most affluent areas that people would would be hobbled and killed by polio right now we've lost sight of that horror because we have a we have a vaccine for polio and have had it you know for as long as most of us have been alive now preventing polio is a trivially easy thing to do and if you if you decided I mean those the people who are you know against vaccines across the board or so worried about the possibility that they have some other downside or who are preventing their kids from from getting vaccinated you know in a very local area it may not cause a problem for them or the people around them but if enough people do it we'll be back to the days of polio right and this is that so like that is clearly no place worth going right and it becomes you know you you move from an environment in which you have this devastating thing for which there's nothing to do and and you just gotta sort of pray it doesn't happen to you to it's trivially easy solved and you're irresponsible if you don't do it right and and and those we will continually be buffeted around by those kinds of changes based on knowledge and and and changes in technology but my main resistance to the to the question is the idea that a lack of answers in practice means that there are no answers in principle and and that a blurry boundary around the right answer means that the difference between better and worse or and even much much better and much much worse goes out the window I think that's I think we still have that no matter how dimly we understand our situation on any of these things so yeah I hope that made sense I mean you know again the only thought that occurs to me and I may not be fully appreciating the nuance of the question so apologies but one of the things that we certainly teach to our students you know standard physics issue with students is it's critical to pose a well-formed question and a well-formed research question is one that's not over determined not under determined but it's one that has an answer and that's a very hard step to get to to properly frame a question so that there is a procedure by which an answer can emerge because the system is not under determined it's not over determines not self-contradictory and there is a unique answer to be found and and the issues that you're describing are ones that typically are under determined so I'm a little bit confused when you say you know the answer is somewhere between here and here what do you mean by the answer well there's an underdetermined quest in this case wait what should be the driving age no no I understand the question but it's an undetermined question there is no right answer to it based on the it's not a well posed question I mean you can make decisions like you say and various people will come up with different propositions for what the good policy should be but there is no answer in the sense that there's you know there is an electron magnetic moment right there is of the answer in that situation because it's a question that's posed in a specific way but it's but there is a gradient great and if you go far enough in one direction absolutely you can feel yourself getting you know cold or cold or cold or cold or we got that and then you go back warmer warmer warmer totally got it so that doesn't mean that there is a bi answer yeah no they in those cases any answer within a certain boundary may just seem arbitrary because it will be arbitrary you don't have you can't specify the right answer I agree yeah okay hi my name is Daniel I was wondering if I get both of your thoughts on the role of the social stigma the societal stigma against being wrong the role that that plays in political philosophical even even scientific discourse and assuming that that role is negative and substantial what can we do on a both a personal and societal level to mitigate and combat that stigma yeah good question I would add to that you know pitch it to you first the there's a stigma around saying you don't know something and and there's a there's a a symmetry here so in science there there's very little stigma around this in fact people scientists defensively say they don't know all the time so it's not to embarrass themselves in front of people who know more than they do at a conference so but if you put a sign if you put a scientist on television and get him or her talking about global warming or whatever it is and they start issuing the responsible scientific caveats about well we're not you know I'm not an expert on this or I don't know that that doesn't translate well into you know popular journalists the journalistic consumption of of information and it's if you put that person up against some bible-thumping blowhard who knows everything they lose so so I get it and and that's why there is not a single video of me and I say this with 100% confidence because I have never been on television talking about something that I did not feel expert in right I'm not interested I get all sorts of calls to talk about things like the climate and features of that sort and I don't do it why for exactly the reason that you're saying I am comfortable saying I don't know but that's not the place to be saying it so to your question you know it is the case as Sam is saying that we recognize certainly as theoretical physicist that most of what we do in our life will be wrong not because we made a mistake sometimes we will make mistake that's the hard time when that happens but it'll be wrong in the sense that it will be irrelevant nature won't take any interest in the direction that our research took us so whatever we published will just rot away in some journal someplace and and that's true for the vast majority of what we will do and to be a theoretical physicist to come to terms with that early on and so we're very comfortable with being wrong in that sense and I think that's a very valuable lesson and it is a good one to have and it does allow us freedom because we're not constantly worried well if I go that direction I'll be wrong go they know we just go and that allows us to have unexpected Eureka moments that change everything but that's as a community the individual will go down many blind alleys and that's just how it is well how do you experience this larger phenomenon which is related of people having a kind of confirmation bias and a sunk cost bias that keeps them wedded to a theory that it's almost certainly wrong for which there's good evidence to believe that you know they wouldn't come to it that way now and you have it absorbs decades or at least years of their time I've never seen that happen yet so yeah right so but what's what's often celebrated in science is that that happens less in science than anywhere else like in science you win points even for proving yourself wrong or for disavowing the thing that made you famous last decade because it doesn't it there's now new data and oh you're the one that finds the problem with it yeah but but you know III think we have confidence that we're part of a community that's incredibly skeptical that's always investigating itself any idea that's put forward the rest of the community takes a sledgehammer and starts to smash on it trying to break it and so we feel confident that if it doesn't break it's worthy it's worthy of further attention and further study so from that perspective it's so rare for an idea to sort of hang out there and the community says it's okay and and tries to smash they can cement and it's completely irrelevant completely wrong we've all been deluded that's such a rare phenomenon so I believe it's really the fact that we're part of this community that's self policing it doesn't need something from the outside to come in and pass judgment it's an internal self-correcting mechanism that allows it to make progress yeah I just my name is Mike hi bride and Sam I'm very appreciative that you guys are here and very thankful that we had such a privilege to hear you talk about such high level topics thanks for coming I have a question that pertains in part to both of you and you'll each have your own area of expertise to maybe give some input on it you didn't really get to talking about different interpretations of like for example the many worlds theory that you talked about I know that Brian you talk a lot about brain theory and that you know spatially distributed universes where there could be copies of us potentially so the part for you would be which is the horse you're betting on in terms of if we were to ever be able to maybe prove that whether it's the many-worlds interpretation or through brain theory that we could indeed prove that there are copies of ourselves or multiple universes and and and one day prove this fact and then if we could - Sam would that be enough fodder to you know write QED on the blackboard and say that all religious dogma kind of goes out the window since we would have infinite Jesus Christ and infinite you know deities in each of these universes and there can only be one true one according to the dogma so would that maybe be enough that you could just unfortunately in some of those universes there are well this brings us to the other thing we didn't talk about the simulation argument the idea that we might be live in a simulation and I mean the concern there is that we could be living in a simulation run by you know the Mormons of the future where more Mormonism is true in this simulation and there's a similar problem in the many-worlds interpretation which is correct me if I'm wrong but if it's absolutely everything compatible with the laws of physics happens in these universes isn't it isn't there some control of quantum mechanics where Jesus is physically resurrected and that's not incompatible with there's some there's some Quantum's because spookiness that allows for things like a physical resurrection don't even need to go to - to quantum mechanics in that incarnation hmm in that in that in that version you know everybody get ready with Twitter because what's about to come out it's gonna be good yeah so so one of the puzzles of modern cosmology is that if we allow inflationary cosmology which is the bread and butter version of the theory that people are talking about if that's the right way of thinking about the universe then ours would just be one of many universes be many big bangs in many realms out there and what that entails in principle is that if we wait long enough in a given universe a random particle motion just random particle motors in the universe will coalesce into any physically realizable structure right so you can just get Jesus appearing or Jesus or Kim Kardashian just appearing out of it and I'm not joking about that so we call it the Boltzmann brain problem after Ludwig Boltzmann who died this day in 1906 and he was the first person to really think about the fact that our universe itself may not have originated from some process in the in the distant past but universe may have existed effectively for an eternity and just the random particle motion at one weird moment happened to coalesce into a configuration that over time then evolved into everything that we are familiar with and that is a rare fluctuation of the particles but his point was if you've got an eternity rare things will happen it not only will happen every rare thing is there so then then we take that one step further beyond what he said which is effectively the point that you're making which is in the future we if the universe exists for an infinite amount of time into the far future which these current theories suggest then these random particle motions sure they could create another Big Bang but it's even easier for them to create something less complex not a whole universe but just create a brane floating in the void so it could be that in the far future the particles come together and they create a thinking brain that sort of has some thoughts and it might think that it's here having this conversation and that brain may just exist for a second or two and disintegrates but if the configuration of the particles is even more special lasts longer and longer and if it's even more special still it could think it's Jesus it could be Jesus or it could be Kim Kardashian it could be any of these structures so so yes I'd rather you not tweet about it per se because it has some nuance associated with it but yeah that would be in our future in these various ways of thinking about cosmology and but also not just in the future if space were big enough good you just you just go far enough in one direction you're gonna hit all those possibilities so if space is infinitely big we don't know that it is but again in the the most favorite version of cosmology that's a very natural outcome the space is infinitely big and there's an interesting thing that happens there which is in in any region like our observable universe the part that we can have interactions with we have a lot of particles here it's a number that you made reference to 10 to the 80 10 to 88 some large number of particles in our universe quantum mechanics shows that there are only a finite number a huge number but the only a finite number of configurations of those particles now space was on infinitely far imagine you have chunks of universe that are as big as ours populated by particles and you ask yourself can figure Asian and each chunk be different well if it goes on infinitely fuller and they're only finitely many distinct configurations there aren't enough distinct configurations to go around the particle configurations have to repeat and if they have to repeat that means there's a version of us out there and there's a version of effectively anything compatible laws of physics out there and not just out there once out there infinitely many times I think you just made me a Scientologist my work is done thank you very much okay hey guys a great talk appreciate it very much all right so I might be a bit a topical I'm gonna ask about animal rights I guess Brian is into animal rights a bit so my question is what is it that's true of an animal that if true of a human would justify stabbing them to death for a hamburger and if you can name such a property something that if true of humans would justify doing this then would you be able to spell out the situation in which we do it to them without sounding completely psychopathic just to give a quick example will not waste time if you were to say intelligence would it be okay to murder low intelligence people if you were to say that it's the fact that it's natural would it be you know okay to murder humans if that were natural etc right and I'll just I'll just I'll just say when we went to dinner earlier he has the moral high ground based on had to sit with three meat eaters eating these like big-ass steaks alright so toss it to you the amazing thing is I briefly considered what to order in light of having to face this moment and then I said wasn't worth it right yes no why make it easy on myself well so there are many so I'm basically a consequentialist which means I you know I just think it the cash value of a moral proposition is in the the well-being of conscious creatures now or in the future actual or possible right so I think there are things that can should be captured that can be captured by by consequentialism thought all the way through that aren't normally captured by it so for instance when you ask why is it you know why can't we just kill if we if we find people who have the characteristics of livestock why can't we treat them exactly like livestock alright so that's sort of a question you just asked well given the nature of what we are as social primates treating people exactly like livestock has a different consequence on us and on a culture and on our capacity to live with one another than treating livestock like livestock so it's not precisely the same problem right so if and so you know that's why cannibalism I mean there's there's there's a taboo around cannibalism that makes sense I guess there could be some world in which we throw off this taboo and that we don't pay the kinds of consequence as many of us feel we might pay right so you we could just you know eat they eat the dead because they're good protein and we're not at all sentimental about their bodies once we know they're there no longer have a basis for experience right but in this world at this moment given it given all the moving parts if people start eating their parents when they die we feel differently about them right and and that begins to deranged a lot of many other things we care about so you have to take all the consequences in view now I I think that it's it's impossible to defend factory farming as it is I mean knowing that details I think that's it's just we want to solve that problem somehow right you know men and yet I happen to think that it's not at all obvious that we can all be vegans and be healthy right I mean we're you know we were talking for him to give the full picture we were talking about the problem of being a parent and having vegan or vegetarian kids right now I my view of that is that you're running a kind of science experiment on your kids and it's not totally clear how it's going to come out right animal again and when I've run that experiment on myself it's you know I became anemic when the first time I was a vegetarian for six years I all kinds of things go sideways in my blood when I the last time I did this experiment for a year now no doubt with with more intelligence or more attention to the details most people can solve those problems for themselves as a vegan or vegetarian but perhaps not everyone can write and I think there may be another solution I mean I'm hopeful that that this whole this clean meat revolution that is struggling to be born will be one solution so there's there's company Memphis meets whose CEO I had on my podcast where they have a meatball that they have engineered out of that does not entail the death of any animal it entails the removal of a single cell from the right animal they grow these cells in culture and then you have you know unfortunately now it's still an $18,000 meatball but ultimately if it could be brought to scale it would be a meat industry that wouldn't entail the suffering and and death of billions of animals there's this if you're if you really are worried just about the experience of conscious creatures there is a way of flipping this around I have no illusions that this will convince you a committed vegan or vegetarian but this you have to have an actual counter-argument if you stipulate to what I want you to sip you light here if it's possible to raise livestock under conditions where they are really living lives worth living right so that you can really have happy cows or happy ducks and chickens or pigs and this which is to say it would be better for those animals to have been than to not have been these are net positive lives well then that's a world in which veganism is not actually the most compassionate solution that that would be a world in which bringing those billions of creatures into existence and giving them net positive lives would be better than than than not if you think well-being aggregates in some way if you think if you have the intuition that having a world with seven billion happy people is better than a world with two billion happy people it's stipulating that happiness accrues in some sense right you can run that same experiment now I'm not saying we're anywhere near there with respect to our current practices and I you know I would completely support every differentiation one wanted to make with respect to the ethics of treating animals well but it's just it's not a given all of the moving parts it's not a straightforward question of saying well obviously everyone should be vegan right now well I would just and jibba saying don't stab them for the hamburger yeah once guys yes and that that is one answer but I think it's yeah thanks to you both for coming Sam big fan on the podcast my questions for you actually and it has to do with AI and when I think about your podcasts you talked to so many very intelligent intellectual people and a number of different topics and I'm interested to know what you are most excited about you talked about you know the pessimism you know related to human intelligence and what we are all aware of and obviously AI is gonna you know really take us to the next level be it from you know the the CRISPR perspective of you know looking at all of the different research has being done here at home or outwardly at you know planetary exploration but from a standpoint just for all of us in the room what are you most excited about in you know the remaining years that you're here on earth when you think about AI and the advancements and the potential that we have what are you most excited about well I you know I think it's the the most important and amazing and necessary thing when you when you think about it going well right like we have all of these problems for which intelligence at some across some threshold is the only solution right whether it's you know how to solve for certain diseases you know or stabilize our economy or understand climate well enough or make various scientific breakthroughs that would give us great benefit and then to think of building systems that can play all of these games that we care about and a right to care about and which protect everything else we care about so much better than we can that it's just it's clear they they need to do it I mean I mean just when you look at what's happened with some a very simple game like chess or go you know me they you know alpha zero a so we've been we've been playing chess for I don't know what is it something like a thousand years right and you have a the totality of human knowledge and ingenuity purposed on that very narrow task where people have gotten just amazingly good at this and people spend their whole lives getting you know we have that we have the smartest people spending their whole lives at this fairly simple task and getting as good as humanly possible and then we build computer programs that that have studied every game we have a record of and they get as good as as it seems that they can possibly get on the basis of the totality of that knowledge and they get a little bit better than people and that's the situation that we had up until you know Google came up with with alphago and then alpha 0 and alpha zero was a program that didn't have any chess knowledge in it right didn't study all of humanity's record of genius with Jess it just played itself for four hours and then beat the best bespoke chess computer ever made right or played it in something like a hundred games and and you know to a draw you know twenty eight times and and you know then beat it you know seventy-two other times so you just just imagine having that kind of breakthrough in every other area that we care about you know whether it's solving mathematical theorems or you know protein folding problems and developing new drugs everything right its intelligence is the only game in town when you want to solve problems and there's there's no reason to think that it's not substrate independent which would say there's no reason to think that all the intelligence we care about that that there's every reason to think that intelligence across the board is just like chess right it's just like that we now know that computers can be much better than we will ever be at chess or it go and there's every reason to think that everything else we're doing on the basis of information processing is just like that I don't mean I think you know that's that's an assumption but I think it's I think it's a good assumption to make and once you make that assumption then you just see all of the ways in which we can solve just problems we can't even dream of solving now and well that will be an amazing world to live in it's also very interesting that if we get any significant piece of that wrong we are just assuring in this it's just dystopian hellscape for ourselves very likely right so is it so and there are all kinds of moral problems we need to solve because we need to build our values into these intelligent systems we can't have you know they'd have to because they have to be tethered to what we want and our own notion of our own well-being and they and they have to be something that we can be in dialogue with so as to refine our notion of what we want and what we should want in the in the future that's that's the the ultimate thing for me would be to have a intelligent system that would be a kind of Oracle or a kind of genie where you could be in dialogue with it and it could sort of map out for you sort of where you are in the you know and this part of the landscape of possible experience and where it is you might find worth going based on what's you know possible for a brain like yours and a brain like yours in in perhaps you know very real you know mechanical dialogue or you know electromagnetic dialogue or pharmacological dialogue with with you know a system more intelligent than yourself so I think the the life could get very very strange and very very wonderful but again there's like if there's like this tightrope walk into the strange and wonderful and off the rope is just this plunge into weirdness and that's not at all you know humanistic or even compatible with with our basic sanity so I think it's I mean it's three because it's a rare science and moral philosophy totally intersect right like this is philosophy on a deadline as somebody recently said that might have been Nick Bostrom and I think you know there's a lot of problems we have to get right and even to even to think about this stuff and it relates to the question that was just asked about you know the ethics of killing animals I mean we could live to see a time where there's there's a just as poignant an ethical question about turning off your computer you know are you committing a murder when you turn off a computer of sufficient sophistication right or are we inadvertently building machines that can suffer you know and that's a huge problem my question relates to claim of utter lack of free will given such partial it is true how do we draw the line between the incompatible nature of free will with reality as you understand it versus our lack of free will in this irreconcilable nature with a functioning pragmatism in other words at the most evil man we can envision is simply a Darwinistic and/or environmental error who happen to a hair a concoction of variances which he did not choose how do we finally calibrate our moral scruples on an obvious contradiction between well-being and responsibility as an example if we were to create a pill that could cure the next kid who would potentially be Charles Whitman it seems a net positive for everyone in doing so however if we try to run the same logic with Hitler and Saddam Hussein in post atrocities our moral edifice seems to fall right under our feet granted such situations are anomalous but I would argue the same logic can be applied and a lesser degree got most criminals so I have two questions for you number one could it be what what's amazing here is what you're doing now people really often hate but you're doing it so well that it's just fun so I'm Hazzard question I'm very nervous right now which is why I'm trying to speak so fun no no it's great number one could it be that the pragmatic implications of a nonchalant happiest can be Hitler roaming around jeopardized Society and therein overturned his lack of responsibility for having done so in the first place and number two where do you draw the boundary between our ethical commitment to curing ill and the devastating repercussions there misapprehensions can cause on society right okay well it's a great question about the implications of dispensing with free will on our morality and on our politics and on our solving problems together well so I think I don't know where we we haven't talked about this but I don't know if free will makes this little sense to you as it does to me I think I think free will is they I think there's no way to think about the propagation of causes in this world that makes any deep sense of this notion of free will and I think if we we understood ourselves if you grant that you know nobody picks their parents nobody picks their genes nobody picks the environmental influences to the system that's specified by by genes and development yeah we were each a bag of particles governed by the laws of yeah and and even if you added you know ectoplasm or immortal souls I mean nobody picks their souls you know or soul what quantum mechanics the randomness of quantum mechanics is that we mean by political choice exactly right so it's that we're sort of on the same page it sounds like so you know but we had to say that and if if we if you returned our brains to precisely the state they're in at this moment we would we would make the noises that we're making in precisely the same way No well but adding random not AG random just doesn't help random it doesn't help but we wouldn't make the same noises we would make different noises but we couldn't choose what noise okay that's very different the totality of influences to the system in that moment but you're adding quantumness or yes yeah so this whole idea of rerunning the tape and running it forward again does not yield the same progression but it doesn't yield the progression that we have volitional choices right got it okay so so quantum mechanic time thankfully yeah quantum mechanics doesn't get you get you the freedom you think you have either so but you have the additional piece we have these cases where you know someone does something heinous like they there was a there was a case that I talked about with Robert Sapolsky on my podcast but that it was in the news where some you know otherwise totally normal guy started getting really fixated on child pornography right so that was you know child pornography was found on his work computer or whatever he got fired and then he started doing all kinds of inappropriate things and they discovered he had a brain tumor and the the judge in this case didn't find the brain tumor totally exploratory for somebody like I think the judge sort of split the baby and put him in jail for eight years when it could have been you know for the rest of his life and you know Robert and I both talked about what a bizarre miscarriage of justice that was but it is an intuition that we all have that once you understand the causes of bad behavior clearly enough once you find a brain tumor that's big enough and in just the right place as was the case with Charles Whitman who you referenced that seems exculpatory that seems like okay this this person is just suffering bad luck he's just beautiful of the diet's biologically he's not the the really evil person who deserves to be punished well my argument is that if you understood all of the causal connections that dictate our behavior you would arrive at that same Epiphany with respect to every evil thing that every person does and what's more if we had a cure for those causes right if there was a cure right now there's no cure for psychopathy we just have people who are psychopaths you know evil people who are reliably doing terrible things because they're selfish and they don't feel the kind of empathy that most of us feel for the suffering of others well then if we had something we could put in the water so as to just not psycho it's a cop a--they just out of the theater of human events we would do that and we would then view psychopathy as a condition like diabetes right there's no not much praise or blame associated with having it it's just a bet just bad luck right now your concern is that I think that we need you know we're in this sort of no-man's land where we don't totally understand the basis of human behavior and what's more we don't have remedies for for people being bad things I understand your case with Charles Whitman and say maybe right but with Hitler it's it's hard right and I mean I would I would grant you that there are on some level we do just want to do what works right and and there's so like the question is did to the question of whether to punish bad people isn't a question of about freewill it's not it's not saying they could do otherwise the question is and then it's therefore it's not a question of them really deserving to be punished once you catch them because they really are bad the question is what are the effects of punishment and a and in many cases the effects are what we want them to be right punishment certain kinds of punishments reliably dissuade people from doing bad things when they're dissuade about now some people are not dissuade able right and some punishments are so out of register with the thing we're trying to prevent that they'd arrange something else about our society if we can't make you know if it was a matter of capital punishment for you know cutting into line at the bank right well then you know no one would ever cut into line but you know we would live in a horrific Society right and there's some societies that kind of approximate that misses you know they're the authoritarian societies like Singapore where they you know they they seem to cane you or kill you for just about anything right and it's very orderly right and so like there are people who will talk about the upside of killing people for marijuana possession because it works so damn well in Singapore now I don't think they have it you know the dial tuned to quite the right spot there but again it comes down to what sort of world you want to live in and I think but but I think this conversation is only going to be going in one direction it's not like we're going to learn less and less about ourselves right and the more and more we learn about ourselves it's going to fill in the blank spaces on the map in a reliable way and they it'll be in a way that makes things look like there's no deep agency there's no deep deep responsibility and there's no bright line between when someone becomes the victim of circumstance you know that the I mean the example I've often used is I mean Saddam Hussein when he's 40 years old is a scary bastard who just deserves to be hung right because he has he's made enough people suffer he he has this coming to him but you roll back the clock in his life well you know he's 18 well he's still pretty scary and you know probably deserves to be hung right but when he's four he is just the unlucky boy who has bad genes and bad parents and a bad Society who was destined to become Saddam Hussein on some level right and and the more we learn about ourselves is going to make the kind of the timeline look more and more like the boys timeline and less and less like the scary man's timeline I mean that's that's what I would argue but that I guess remains to be seen and Sam we got a a minute to finish up here if you guys have any final thoughts for the evening okay so sorry we just got to the end of the voice of God tells us that we're time is real do you have any any closing point that you want to make no I'm good all right everyone please give a big round of applause to Brian Greene and Sam Harris [Music] [Music] all right everyone thank you all so much for coming we'll be back soon let art and science inspire good night thank you

Channel: Pangburn

Views: 77,727

Rating: 4.7096467 out of 5

Keywords: sam harris, brian greene, science, reason, god, AI, artificial intelligence, religion, cosmos, space, time

Id: 5pbHsRz8A7w

Length: 126min 55sec (7615 seconds)

Published: Tue Jan 08 2019