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" Hello I'm -- from -- and I'm Robert -- and this is radio lab podcast. Which -- is not really of them the -- of the bill -- we'll powerlessness is the -- in this park has been taken to New York City to the 92 street library to a series -- giants of science and on 18. Something very cool. With -- and so I really letter I thought I saw you there three. Vehemently they had told told them that I -- set up at a guest is about them I don't have to let's just go to the hall and Robert on tape will take over from there. The the man you are about to me is he's a professor at Columbia University mathematics. Also professor of physics to Columbia University. He's also the director of the institute for strings cosmology and Castro particle physics at Oakland University. He also best selling author whose most of them were -- called mirror symmetry which means and mature what exactly."

" It involves -- relating to different -- manifold letting the colorful what do we are hopeful that your tree all about. He's a Rhodes scholar he's the author of the elegant universe apparently not a -- person at all. Yeah. He does however believe the most peculiar things so if you ask him and I -- he believes that if you travel. From this room in this auditorium in 92 street and Lexington avenue. In pretty much any direction at all but he -- reason he really really far like yours apparently used upon like -- out. You will if you travel far enough you eventually find a galaxy. But that looks and I mean exactly like I'm -- And in that Alex you'll find a plan that is an absolute copy did bring -- our planet earth. And on that -- you'll find a city that is uncannily down to the here's on this CD rap acts exactly like this city New York City. Adding that there will be a another 92 street YWYM. Each day. And with -- building that has another auditorium and it that is exactly like this auditorium here and if you think that's an unlikely Clinton and I'm just getting started because I think going you will also tell you. That in that distant distant distant auditorium on the other side of the cosmos backstage waiting to come on the stage. There is a another professor who also teaches both mathematics and physics. At a school just happens to also be called Columbia University who's also the director -- institute history of cosmology and after particle physics. Who also just happens to reading writing mean within EUR Indiana like this one when I hear. Act and who happens to have an identical set -- also two sisters in the same mother in the same -- at the same memories down to what he -- this morning for breakfast would would not DNA. Because the faraway Brian mean like the nearby brain being are both of them vacant. And when that went out and out favoring -- and I were just mentioning -- And in these two rooms at these two identical professors what they're identical -- Are going to be talking to -- yes and identical audience watching. Which an exact copy of every one of you sitting here in this room right now with -- all -- histories and all -- memories your exact copies are sitting in the other room on the other side of the universe. Including you you in particular. And you and if you think you -- self respecting Columbia University professor would actually I don't mean this politically but actually believe. That is a copy of us on the other side to make it even crazier. Brian being believe there's not only one double -- room with a double to undermine -- in the double gang your audience you be there are countless. Doubles Abbas in every direction out there in the great beyond what's more. There are rules exactly like this when with just you missing. Or just mean missing with the color of my shirt slightly different in other words in the big enough cosmos. It is an infinite cosmos going -- things that anything you could imagine almost anything that can be out there. Will be out there really helping. To which I think -- a couple of plastic. Could do you really believe -- and if so wise let's ask the let's welcome the local homegrown version of a man like that call Brian -- So far so good I get it right more -- There's an assumption you left out but we can get. But talk about two words infinity and universe to -- in in the first we start if that by discussing. What you if any -- security and you've described it as the mill go Imelda Marcos wardrobe problem. So in between that we that we we have a woman here who does not like he's being seen in the same outfit twice to tell us what how she solved it."

" That's an interesting way to get into the subject -- didn't anticipate the that is where we would begin that's good. The the issue that you're referring to is the following. If you have. Finite number of distinct ways in this particular case dressing right. And you have say an infinite number. Days and evenings -- which you have to step out. Then it's pretty clear that you're going to have to repeat. An outfit. Once twice in fact innumerable times because the only thing -- had ten different outfits or in the case of and old the example there. Forgive him 500 dresses and 1000 pairs of designer shoes right -- ago so you can envision the number of distinct combinations that dresses and -- very easy to figure it out. 500 times a thousand and then if there more than that many days. -- that individual that Imelda is going to have to repeat is going to have to repeat given outfit if there's -- infinitely many days and only on a number of out it's simple idea. So it just to make it."

" Simpler Stewart appears -- let's do it as a coin toss the odds against me getting 3000. Kids in a row -- what are -- infinitesimal. But if I kept tossing and tossing and if I -- infinitely. In the of course had been hit that."

" That's right you do a thousand coin tosses. Over and over and over again. And look at all of the outcomes. Then even the most strange kind of outcomes will peers such as all heads. And in fact if you flip those coins enough times say infinitely many times. Then that's strange outcome will actually appeared rarely. That infinitely many times he. So now let's just use that logic and apply it."

" Two in just a different kind of system imagine a cosmos. Which has into infinite space. Now the key thing here I think is that the stuff in the cosmos you believe as some kind of find right -- the rules. So let's -- her this woman in the in the would you believe a pinkish thing that you -- okay. So who he is a compilation of atoms which follow certain rules. Her memories. I assume you think also. Adams."

" I do not everybody agrees that every aspect of your personality your conscious being. Is reduced to bull to a configuration of the atoms that make up your brain but I certainly believe that that's. Dreams memories that's right there's nothing else all you are is a bad the particles acting out the laws of physics that's me is pretty clear. -- tasteful they view it. The kiss of god we just don't included in this series you can if you like I just don't see any particular the need for it's -- for this discussion. -- its."

" Always come outlawed. So. So if she is just a large number of Adams any particular Miree. But let's -- she can. We can travel infinitely. And look at all -- and -- he knew what I guess about particles are about forces were about."

" You can reduce everything basically -- particles that that's a fine way of -- the whole conversation. Any ideas that you're getting is indeed the fact that if the universe is infinitely big. The rough idea that we can make precise in a moment of its infinitely big. Then the number of distinct configurations of particles like the number of distinct possible coin tosses actually is finite. And -- the universe is infinitely big. Then just as you're going to cause this after repeats. The configurations of the particles will have to repeat you just officially far out there and the configuration of particles will repeat. And will indeed make a configuration of particles that looks just like this room. Looks on the outside or or he is so so he had a dream last night about a black cat walking on them and fires it. She is also deeply in my but the man next to her in the here enormous number of and experiences again. And she's wearing the pink thing there so we have a lot of atoms they are doing very different things if indeed you're doing these things at all. You -- day. That that combination be intimate inside and outside comes here we'll be found elsewhere again and again it is an -- same boat. And -- outside. Will be found with a distinct inside many places out there. But be outside with the same and I've also be found out there because again it's just another configuration of the particles. And since their only find in -- distinct possibilities it's a huge finite number it's -- gargantuan. Fine number but it's a finite number. As we -- sufficiently far out. There's just so many distinct configurations that there can be -- their planet in many that the -- officially far out have to repeat. But won't you run into -- could trillion people old laws like her are absolutely and much easier to reproduce. This this woman in the first row with one particle and a different place or -- particles -- different as a much easier because there's less constraint. If you want to reproduce this individual. Completely. Every single particle has to be in the right place. That just means you have to move further."

" Now you. I know we're speaking here and this has this makes perfectly logical sense it just makes absolutely no practical sense of submit. I was wondering what it makes sense to you as the person. Do you seriously think. You literally think that there are two people exactly like us with."

" With our dreams are thought to the in some others stage right now where would have you called now. Over and over again right now all the over the unit risk for you just say that."

" Well there's a key element that we have been assuming. And we even assuming that the universe is infinitely. And we don't know that the universe is infinitely been. It could be that you go on for some distance and you walk and you walk and you wind up coming back from that direction sort of like the surface of the year. It has Esther to side with not infinitely -- it doesn't have an -- he can't fall off but nevertheless. When you keep on going to return your starting point it could be that the universe has that kind of shape. The Davis seems not to support that at all at the moment. The best astronomical data does not support that supports the universe that is flat as opposed occurred. And if that's the case is still possible that the universe could be. Sort of like the surface of the earth in the sense that it might be like the surface of video game screen if anybody who plays pac man or any other -- you know that you and miss pac man falls off the right side of the screen it doesn't disappear he comes back on the left side and the theory. That's another possible shape for the and it has the names of the -- us. And our universe might have that particular shape again it's a finite -- But he can't falloff we don't -- didn't fall out of the universe that would -- way to have a finite universe we don't fall off. However. The other possibility is simply that it goes on forever. And we don't know which is right the simplest one mathematically. Is that it simply goes on for ever and if that's. The shape of the universe then yes IE fully believe that we are out there and some notion of now having this conversation and not once not twice -- in many times. Both sides in the deep creeping well let's talk about the -- this. Yeah I mean. There is and a notion that we all have that we are unique individuals and that there is the real version of us in my case you're -- that it. So you just said that a million billion pounds children gather here. Well so where does that leave you do you just feel like personal identity -- Barry R I 418. Wheeler personal identity in this context is very very strange there's literally no different. Between me and the other guy out there. And that's okay with me. I don't really have a problem -- that but I do agree that it challenges your sense what your personal identity is all about. Your the collection of your memories. With terror ultimately just a collection of impressions. In your brain just to collection of particle configurations. And at that other individual has the same brain configuration because the particles -- and it tentacles stated they are in my head. That person is as much me as I -- me. It doesn't automatically make you want to quickly run off the stage hide under a pillow. Do something the other that could never find out and then be different. I know that you'll have exactly the same thought. It won't help you very much but that's really creepy to be chased around by the by the by the infinite number of double gang -- so it what you everything you will to do they also will to do simultaneously and there infinitely others that will to do something slightly different. So this -- richness to the world. But in an election is somewhat different than what you had in mind I think most of us have in mind that if the universe is simply -- keep on going need. He -- landscapes. Keep on going -- new stuff new stuff new stuff that our picture of what reality is and that kind of the universe our universe. And I'm saying that the laws of physics don't support that notion the laws of physics sport yes -- the rich world out there. But a distinct landscapes the distinct environments the distinct configuration that you can -- limited. What about how far away is the nearest one to me well -- good question. If you can actually calculate dead and as you might imagine it's a pretty big number. Because I'll give you a number from any mark take market MITI have no idea what this means. What is ten to the power to into the 29 meters. At the big number. And yet you know what it means it's not like and Latin. -- just just to quickly threw them in I think you're familiar we know what what tend to the to means it's a hundred just do one with 2 following it. In this particular case you take -- to the 29. Big number one was 29 the adapter and you take ten to that number. Which is that many zeros following ten to the 29 zeros following the one and it's so big that we and I have a name. -- and called the crawl went through -- it's a huge number. And it just is commensurate with the fact that even though we're saying that their finite number of ways that might particles my electron might protons -- court. There's a finite number of distinct ways that they can be configured. It's a huge number. So you have to flip that coin many many many times before you reproduce that particular sequence this particular configuration. Let him in -- you know Islamic distress in the infant universe tenth of ten to 29 is really small I mean infinity is. Hard concept to wrap your mind around. Here and you take half of infinity you've gotten them -- if there -- a ticket temperament and you've got infinity still. So this number however big it may seem by human standards is just a little tiny blip in this infinite cosmos. Well there was one other assumption that we made and I just munition -- attention to a youth that. That."

" All the particles that make her and all of the forces that join those articles. Are of finite group. You know that -- you know was what you can see year we're we -- Why wouldn't you know what who whose dad. Well again there are underlying assumptions that the laws of physics that we know about here are the laws of physics that -- the universe everywhere. That's again a rather simple assumption that. We don't know to be true certainly our observations of the universe suggest that the parts that we can see visually. Are governed by the same laws of physics that -- the phenomena we can see the world around us. That doesn't prove that to go sufficiently far out the laws might change simple assumption is that they don't change and that's certainly what I am assuming. -- any ideas you know perhaps that the slightly confusing focusing on one individual particles what we're really needed all of the particles. In the observable universe the part of the universe that can influence itself by virtue of exchanging particles and exchanging forces. This particular. Part of the universe has a certain large number of particles. And that large number of particles has a large number of possible arrangements. But a finite large number of possible arrangements so on most of those arrangements there won't be people at all. There's -- particles will be haphazardly arranged they wanted to coalesced into structures that we call humans. In some of those universities will be one lonely human the only person that formed at the particles in the universe. And a very tiny fraction they'll be universe is that look like our. Was she slipped in this world for."

" Universe a universe has split with because I don't know like -- you do that lets us do that. We really used the word when you use the use word universe I use it in the common sense that it includes everything that we know. Or that we can imagine. That seems to not be even remotely what you're doing."

" What we now with that notion of universe. However all encompassing. It sounds. Is a little too course. To accurately describe. Modern thinking about how physical universe actually works. And we find it more useful. To have words that. Delineate. The universe we live. Finer characteristic that lumping it all together into everything that you can imagine everything that's out there so for instance we imagine the observable universe. That's the part of the universe that you can in principle -- with a sufficiently powerful telescope. With the sufficiently powerful receiver you'd be able to exchange signals within those parts of the universe. We believe that there -- parts of the universe that are just beyond our ability to Steve because -- not enough time. Since the beginning April light or any other influence to travel from -- distant location. So that's the part of the universe that's kind of separate from -- it's not within the observable universe. That some people like to think of our observable universe is one contained universe and the other regions as we found -- other universities. They're not that distinctive principally can get through them if you traveled sufficiently far to just regions that are beyond our ability to exchange influence with today in Christopher Columbus sort of way you get on a boat you ride to the horizon you go over the horizon you keep going and you see something that no one has seen before -- you know that -- we don't that we use the same word horizon suggest as. You mention Christopher Columbus and look to the horizon and knows that there's something beyond the horizon but can't actually see it. We look out into the cosmos. As far as we can and we believe that the stuff beyond what we can say beyond our cosmic horizon. How much space can we see. What's the observable. Roughly 42 billion light years in any given direction. Forty Cuba that's those that lose the being tired the diameter the mean that's all the way across you turn to the left you look. From number that way turned to exactly right so you look out this way can see about 42 billion light in a light years of ethics trillion miles it's again it's far. But it's a finance. What what is your country you do -- Columbus to go over the horizon and you travel or an analyst at stake if you're in the the observable universe you move over eight. 100000 light years to the right right. -- can you know -- stuff that people from here couldn't because you know over there -- absolutely. You have any sense of whether the stuff you're going to see will be all America big surprise or just more of the same then. It will in that small motion that you described. Today 42 billion plus light years we believe that will be particles. Entities. That -- same laws of physics that particles and entities and our observable part behave according to the same rules. But they'll be configured so much differently you won't see another America that's what you're asking out there because. It's still unlikely you need to goes far enough away. That use sample more possible configuration and just won the neighbor next door and that is -- he said to me if I take a coin. And I I flip it once and -- that particular sequence heads tails heads heads tales if I flip for the second time like exactly the same sequence. That's unlikely if possible but unlikely but if I flip that five point sequence. I do it a billion times will -- ever get that same sequence yes that's very like. So. It will. Is there -- place out there we're conceivably. What is predictable over here changes. There the is there. Is there any neighborhood and that's where the laws actually my Hamlet yes absolutely so in fact when we study modern cosmology with greater intensity. We find that it's probably likely. That if you. Examine the universe from say a god died view so using that capital huge universe that you started with that you can sort of see in some sense the whole thing not just what we individual humans have access to because -- the whole thing. Then you'd probably find according to a appeared called inflationary cosmology that we can discuss -- be like them but according to this theory likely complexion of the universe. Is that there are a variety of bubbles. Bubble universe is ours is just one of his vast cosmic bubble bath of universities and in the different bubbles the laws of physics. Can appear to be somewhat different from the laws that we are familiar way when you say they became -- gift."

" And so are you talking about. All hydrogen but no oxygen are you talking about -- we don't have gravity here. We don't -- do gravity of earth yes they don't actually have a week -- it's it it."

" It's more the former but actually the distinction between those two examples is not as. Clear cut as you would envision so for instance if you talk about not having. The nuclear forces which is what you're alluding to. It's possible that the nuclear forces can be in our universe as we measured them. And and that other evolving universe but the other -- universe. They might be so weak. Compared to their strength and our universe that they don't have much of an impact the impact might be infinite has only small compared to the impact and our world. So for all intents and purposes there might not be in nuclear force in the universe compared to news reports and hours. -- and -- Little complicated so there are weird here with a set of rules and a set of operating systems that we have somehow magnificently begun to figure out. And you -- they might be a neighbor we're all of the principles that we beat it beat that have to organize life and existence here. May not be covering quite the same way but I can kind of thought that we hear eventually attached to them the these bubbles you talk of the are you are different kind of -- bubbles where we don't attach so before we were talking about the laws of physics here. Being famous the laws of physics way out or we can see and and beyond the horizon. Think of that'd taken place in one big bubble. When we get to as the easy ordinary regularly ordinary but. And the -- really want to stresses these ideas do not come because we don't have enough to think about and the imagination run wild. When we study cosmological data. And again I'd be happy to talk about -- I'm not sure how Beethoven want to get we study the cosmological data it leaves us almost an X through -- To this picture. Where there are more than one bubble. And these public universities are not talking to one another they're not touching each other you can't reach the other bubble. You can't traverse the space in between in a meaningful way. And that means that over here that they we leave here so we have of this thing. So. We are over here so that's. Now. Does something come out of the and do what again or does this happen and over there you're guy apt."

" As a little crying technical a technical the accurate in these questionnaires -- let me just another way of thinking about it that that that may help -- and we can do to combat that you think that was clarified that. -- the well I've is startlingly clear myself at -- at. If the way I like to think about it is this picture this inflationary picture it is if the universe is big. Block of Swiss cheese."

" Now just -- thank you know. Is it like a big pockets with keys where the holes. Are the universe is that we're talking about. So everything that we know about is one hole in the cosmic mysteries but there are many other holes in the conflicts with trees. And the point is when we study this picture that emerges from studying the cosmological data not from an overworked imagination. We find that the meaty part of the keys. That beacon management -- but you know beyond the white the white part of the keys expands so quickly. That's the bubbles the holes in the keys are pushed apart. At an enormously fast rate faster than speed of light and that's what prevents one from even in principle. Going from one hole one bubble our universe to another whole another bubble. So our universe and the other universe is are all embedded. In this environment this cosmic with trees but we can't traverse the -- part because it's growing so enormously quickly. Oh dear he now."

" Let's go with your metaphor here. So we have this big Swiss cheese and meat of -- him something of the boot the -- is that there aren't over yet. So now we're inside were in space. So. This is your keys whole minute okay. So I'm living in the air you know and my universe is getting bigger and be yours so these Swiss cheese has the a hole that his goal is growing our -- is growing. And you're saying that the keys at a right part of the -- is also growing and it's growing faster than the rate at which that hole is growing. So there bigger holes. But more keys. So if you are saying you have -- this particular evening about your by the American dairy association -- We'll be doing it in Wisconsin next week. So. -- reason I can't talk to you if you're in your -- among his arms you're growing Euro over the are growing but the space between us. We would be flying to I decided this stage it. Faster than the speed of light yes that is feel like -- tentacles that housed a possible nothing goes faster than the speed of light. And the thing to remember is that when Einstein established that nothing goes fast in the speed of light but he really established. Is that nothing can traverse space. And -- speed greater than the speed of light that is equations full well allows faith itself to grow. At any XP bigger than the speed of lies perfectly fine."

" Okay I'm gonna hit the keeps coming up because otherwise we get completely lost so. The universe -- is a series of expanding empty spaces inside a web of some kind the call of the big -- And that the web's growing. War what I don't still understand is we're getting these -- come from."

" In Swiss cheese I have no idea where those holes completely. I consider this the -- dual whole problem myself. What can you address please these facial halls of believe the theory holds for another occasion yes so. So in in this version of cosmology against called inflationary cosmology what happens is. In the beginning whatever that means. Bases filled with something that we call a field. In input Tom field the name of that and the field is very much like an electromagnetic field that the crawl pretty much familiar with that idea that there are electromagnetic waves going through this room that's how you can use your cell phone to talk to somebody far away the electromagnetic waves of defusing space. Those electromagnetic waves or fields electromagnetic fields. This inflationary theory invoked the new field not electromagnetic field that fills all space. And it has the amazing property death by virtue of Billings -- it causes -- be filled with repulsive gravity. That's what this deal does repulsive gravity pushes everything apart. This is. Gravity normal gravity brings things together this is the ugly -- that's right started out of my way I write Einstein himself as the one who found this is an old idea repulsive gravity -- back -- 1917 even those not widely appreciated the gravity can be repulsive. And in this environment of this field filling phase gravity is -- the drive space part. As -- driven apart it turns out that there are regions -- this field. Drops to zero value it quantum fluctuate to zero value and those -- the holes. So we our universe. Is simply. A fluctuation. In this field where it had a high value and it dropped to a low value thankfully been giving rise to the universe that we are familiar with. And that when he's with at the drop is Eric gives up its energy. To the familiar particles that make up you and me in the world. All the particles that we know about this version of cosmology come from the field dropping down to zero. Releasing its energy. To particles that give rise to the stuff that we are familiar with -- that field can drop to zero all over the place. Giving rise to a bubble universe era all the universe Arab all the universe there. But in between the field still has applied value -- basics. Or understood about 5% of that but. But maybe -- let me say it Mac Q I mean how -- so. Under. At -- underneath everything. Leaders this."

" Whoa whoa whoa whoa whoa look look."

" Sometimes it gets hot sometimes we get called it didn't walk anyway. And sometimes it spits out this space. And create space and sometimes just of those whom has been monitors -- so so sometimes you get."

" An explosion of nothing which in melt down into us and sometimes you get very much at all we just and that does this sort of being underneath everything that's doing as long as biting me everything you mean a region of the universe in which this field has. Repulse the gravity -- can drive space to expand through the cheesy parts of the Swiss cheese are the places where the field has finite value. And the holes in the Swiss -- or Whitfield has dropped to zero. So this please read it and Infiniti I get on the universe side. We what we an -- is varied distinctly different neighborhoods each of these bubbles can have its own characters so some of them. You could have. Atoms that come together happily inform trains and in four months to me you can give rise to intelligent things and other and you just get like. Standard. And we really boring for a yeah yeah exactly so then the the universe is cut is it is is this an infinite universe this --"

" well that that's -- that's good questions that -- number of kinds of infinity is it now come into the story number one can ask how many different bubbles are there how many different holes in the cosmic was keys are there. And indeed this is a process that we believe to be eternal. And they're for they would actually be an infinite number of these little bubbles -- our bubble being just one. And I might say but wait -- you start up this conversation talking about. Space that we have access to. Going on infinitely far if our universe is a bubble no matter how big it doesn't go on infinitely far it hasn't size -- it. And a way that I urge you not to try to. Describe in any detail here because it's pretty tough. His stomach on the outside it looks like this bubble has finite size. Anybody in the inside it looks like in his infinite. -- conversation that we had fifteen minutes ago about a universe that goes on forever applies here even to each of those individual bubbles out. Any Hubble space goes on infinity so -- an infinite number of copies of us having this conversation inside -- inside a single one of these bubbles and and you got infinite number of bubbles -- Anything else can be going on. Could be Andy again and again the danger is busy danger that people's among thousands of foreign nut. This is it's pretty far out there it is not this is a very minimal. A very minimal approach to describing observations that we have. Observations of the cosmic microwave background radiation and observations of the early universe by looking deeply into space. Can only be understood. Largely speaking. In the context of the framers that we discussed and you'd think we all these nutty ideas come from very very serious primacy yes they don't come from people saying let. Think -- nutty idea and examine its consequences. They come from people saying let's do measurements of the universe and try to come up with theories that explain those measurements. And I'm going to ask you went measurements. Those where literally. That's not hard to describe facility. Measurements of the temperature. Of radiation. That we believe is left over from the early stages of our probably universe. You measure the temperature of there the temperature over there and so forth and you get certain numbers that you try to explain them with theoretical equations. And the framework that is evil to best describe them winds up -- all of the additional structure that we're talking about. It comes along with the theory that something that you put in from the outside. What --"

" Weird as I know again hear what you told me before. In addition. Managing now the universe in which he bubble in which we have carbon and hydrogen oxygen all the forces that we're familiar with -- and we. Man and man clouds of gas and you and me. Over and over and over again -- And we have another universe not too far over in that direction which in which very little happens and that would which we get halfway there another -- which are very odd things happen. What about this. One of these bubble universe is produces super intelligent. Computer geek. Intelligence being. What they do. Is they do -- Thing come up with a super computer. Fabulous supercomputers that create the universe so spectacularly. Realistic. That the critters you and that won't need the universe think there -- you can meet you mean. Our universe and weird universities and weird green irises and you eliminate a Soviet totally be universe."

" Now -- can't you eliminated it's actually quite likely. And the you see in our universities using that as a benchmark. That we're getting closer and closer to being able to do exactly what you're talking about. And magic and technology. A thousand or 10000 years -- 100000 years down the road. One presumes that if progress continues apace. That we will be able to create the kind of simulations computer simulations. That to those. Bits that are being manipulated and that's stimulation appears to have a reality in much the same way that you're familiar from the matrix. You anticipated that likely to happen in fact you can go one step further just do what -- so that people in this."

" Sixty universe would be creatures -- fiction made up by computer program. But the fiction would be so specific so beautifully detailed. That these creatures. Fictional creatures in someone's mind to a computer. We think they were -- would think they fell in love -- think that they were having so -- would think they wanted to be -- Short."

" The chairman it has nothing specific to do with any of the work that we. Physicist and string theory and cosmology are working on. I'm going to take that as a given that the natural progression of technology can lead to that kind of an outcome. I have no particular expertise -- stated that will happen but a glance at the trajectory. Technology suggests that that's a possibility. Now the place where. The ideas that we're talking about come and is the following. If you ask yourself the following question. Is it more likely. That upon being that he's reality. It more likely that's real reality they came from the universe creating it is they one of these bubbles. Or is it more likely that I minutes simulate."

" And all we're talking about here leads to a rather interesting conclusion. Because. For the university create a reality that were from they would it is a relatively unlikely. Course of events that the universe is trading on these bubbles the particles are coming together in one way or another. Randomly joined together according to the laws of physics. And only in some real tiny fraction will the configurations give rise the human beings say that see the world the key into the one that we three. That's rare. In one of those -- though if -- you have these super intelligent beings the United different on this super expert at dealing with the technology of their time if they can't create simulated universe is. It's much more direct route to a reality that we would consider. Into what we experience it's not random. If individuals actually creating the simulation in fact they can -- simulation after simulation after simulation after simulation. So in that universe there are many many many simulated world. That -- in those -- consider real and they're for from that perspective -- more simulated worlds that appear like the one that we see around us than there are real one. Now."

" So the chances after being any naturally occurring. Real world. Might be smaller than the chances that we belong. To the fifth grade project of a geeky kid in the planet and Antar. I don't know how you live with this stuff. And we will we just sat down. And you already told me that we are. Duffel angered up the good zoo we -- seemed to have no real identity. Free will is an open question. And we're probably a fake."

" Why and you want to become like soccer players something we're normal. But. Actually sincere question -- do you actually. You killed the."

" Is -- when you believe these things to be true that it doesn't get you down."

" No I think it's incredibly -- I mean to me the most wonderful thing about signs and and physics in particular there. Is the fact that through the power of thought and calculation and observation. You can be led to conclusions that the odds with the what you with."

" Think based upon experience. I don't think there's anything more wanderers in that moment. When you think the world as one way. And your equations your math your ideas your theories begin to convince you that it is another way. And we've seen this played out in the history times over an organ and indeed the gentleman developing quantum mechanics in the twenties and thirties. From Eisenberg aboard throw under and so forth they began by speaking at the world was basically. And Tony and world a clockwork universe as it was called. Where things evolve according to a very precise that a -- tell me how things are today and the clockwork universe tells you how they will be tomorrow. In -- generation they realize that that picture however compelling was wrong. They realize that the world -- rises and develops according to probable list of rules. Where the best -- can Tuesday that 30% chance that things will be this way and our 4% can't Tibetan point 2% of that. That was such a paradigm shaking way of thinking about reality. It's not that they get you down it's something that pumps you up and if we and if we are now perhaps learning. That the very nature of reality at least need to be questioned. It doesn't in any -- established that we are in them stimulation because it's more likely perhaps that we are in one but it's still be in a real universe. But to me it's wonderful to get your sense of reality -- to get a kick in the head. And to at least be able to contemplate the real possibility that the laws of physics are suggesting that reality is not what you think it is."

" Although he appears seeking to be pleased by what you see if you want to feel joy. And hug that give you a -- image -- If I shoot -- cannon ball into the air Newton and Walt physicists can tell me if they knew enough exactly where the cannonball was going to go. It's fixed and it's understood and that the -- has no Krewell in this matter you know. What the image I like -- a fight for Africa -- bird and you would in the area where people predictably took place on the ground but a political life where. And threw it up in the air."

" I hit in principle predict where homeland. A -- to knows."

" So much I don't need to -- so much but that's find beat the fine print. Ewing you I think have in mind that the -- has them free will to go that long ago. And as far as as I certainly can now. There is no place for free window in our understanding of the laws that. However diminishing that may make some people feel I think we need to perhaps faced up to the real possibility. That the notion of having free will is an illusion. It used pollution and makes life interesting and it's one that you need to put to decide because you need to live as though you do have free will. But all there is is it."

" Don't Q. And there are a lot of people -- Brian heard David gross Martin Gardiner who have some real problems with the smoke keepers currents that rhymes and run a few of them by if one of them is there. To conjure up. A universe in which everything that could happen is happening. You know so there are lots of Brian Robertson -- almost -- Robertson very almost imposed almost the most I think. That's going to break one of the basic rules of science in the keep it simple rule comes -- mean if you can or I'll just vote Martin Gardner. Surely the conjecture that there's just one universe in its creator. Is infinitely simpler and easier to believe there are countless billions upon billions of world."

" It does sound simpler in some ways and I have to say I'm going to give you two answers to this issue. If it turns out that our future understanding. Eliminates this idea. Parallel universe is multi -- theory. And -- telling on the way to think about it this is one university and calculate everything it uniquely determined by the laws of physics. I think I'd be happier with that -- So don't get the misunderstanding that. I have some emotional connection to this idea. It's where were naturally led by a variety of interesting ideas in -- for need to be taken seriously but in terms of it being simpler. To have one universe versus Manning it really depends on -- you define simpler right it is simpler to have. One of number verses many are all numbers in fact if I give view. The 22 digit number just 122 digit number. And I ask you to repeat its main. Verses I simply say think of all numbers in just count them off forming. Which half do you think you'll succeed at -- and we 22 you -- not -- that gave me a two digit number I gave me a but that's the thing Howard University that characterized by two digit number our universe is characterized by. A great number of distinct features and math of the electoral on the -- for the court the strength of gravity of the strength of the electromagnetic force. They gates symmetry of the standard model the equations of general relativity and on and on it -- A whole long list. Of ingredients that need to be -- so. For the universe as we know what to appear you get them after the electron a little bit wrong when you repeat it to me. The world is different you get this -- the gravity a little bit off when you repeated to me -- world with completely different so there really is a -- analogy. There's a long. Number if you will that characterizes. Data. Verses they're being all universities. -- being all numbers and in some sense. It's much easier. From complexity standpoint. To describe all numbers -- is described as one particular 22 or 44 digit number. In -- he can make -- exercises and has an algorithmic complexity. Which is the amount of information necessary. To say give to a computer. Just sit back. A piece of David a year interest it and now occupied a very short computer program that will spit out 123456. At one line computer code. If I want to -- out some particular number. Well I may need to actually type in every single digit of that -- report does that affect me that is greater complexity not less complexity. And I'm only trying to emphasize the fact that even though you'd think of one university more simple than many. That reasoning need not actually hold up under close scrutiny. Would just."

" So -- you do. You're saying that. Our money and ask you what the problems but serious people. Trying to figure out things that they can measure in things that they can see and things that they can examine. When they looked at the -- the present. Looked hunted the man who lead them to these two distant. Multiple unit responsible directly or over and over a committee to read many different directions from classical."

" from quantum physics they're variety of different ways of having multiple universe is redacted describe to tonight the idea that he goes to proceed far out the universe repeats. As that there are many world out there much like ours where the can be these many bubbles where there -- many universe now that it may be like ours or not. And these are naturally coming from simple ideas. That we allowed to run their course I should emphasize this is not a certainty. By any means. Physics science we all know with the dynamics subject where new ideas come in and forces to reevaluate and to rethink things and I would be thrilled if ultimately we do find that there's one unique universally consistently calculate everything about it. That would be thrilling. But it's also thrilling to imagine that that isn't how the world really put together and that he did that we now have ideas that were coming up with. May be revealing. It's true underlying reality."

" I so so we we're left with a bunch of choices we are. Infinitely duke looked capable. We live in cheese in the expanding holes. -- he's EU. We might -- reflection of a computer we might be a pale reflection of mathematics. We might be actually made of real stuff in the here and now. Or not."

" That was professor Brian Greene and conversation with X you -- should -- This recording was generously provided by the 92 street Y and they have more of their -- available of their website WW dot 92 YE dot org you can also check out our website. -- WW dot -- out when word de --"

" Media loves funded by the Alfred. And -- run and I'm Robert Krulwich picks listening."

" Thanks for listening to the radio lab podcasts from WNYC in New York public radio the station radio lab called home this podcast as a freeze."