If the Multiverse Is Real, How Do You Know You're You?

We're basically the most highly evolved form of the most ubiquitous thing in the universe, which is dust. So the dust that makes up stars and planets, actually, without it, we wouldn't be here. That's about as out there as I'm going to get, okay? I'm actually going to do a lot of basically orthodox cosmology. And I'll explain to you what I mean. But in doing so, I came up with this subtitle, you know, that actually perfectly encapsulates what we'll be talking about. And that's Twinkle, Twinkle, Little Star, How I Wonder What You Are, Like a Diamond in the Sky, Up Above the World So High, Like a Diamond in the Sky, I think. I don't know. I've got young kids at home. They know better than me. So, that's the theme for today, and that's what I want you to think about and hopefully motivate to you how we know so little about the cosmos, but we're so ambitious as to what we do want to learn, and that, I think, is what's so remarkable about being a human being. So what am I doing here? Well, I was nervous, as I said, until I read the description that Stuart sent out, which was quite reassuring to me, and it said, questions that will be explored are such things as, is consciousness intrinsic to the universe? Check. Okay, I'm a cosmologist. I know a thing or two about the universe. Okay, I started to feel a little bit better. Then the question of how did life and consciousness evolve? I might not be able to say too much about the latter, but the former I can speak to, and I'll in fact give you demonstrations that indicate with materials that I've brought here, the gifts that I'll be leaving with Stuart, that actually will help to perhaps motivate this theme of the twinkle, twinkle little star motif today. Next thing that I want to talk about is how can consciousness causally affect brain processes. Is that what it says? I think, okay, brain, that would be nice. Nice, okay. Brain, okay, I will mention the word brain, and I'll talk about a very outlandish aspect that of, in the cosmological model that is the dominant one, maybe not the correct one, but the dominant one, that seems to predict. The existence of these exotic phenomena that have consciousness, the lowest form of conscious material or assemblage of matter called Boltzmann brains. So I will use the word brain in my talk. And then last but not least, do we have free will? This is a pretty big subject, right? And as a cosmologist, I can comment on this, and I'll discuss how it may relate to the multiverse and things like that and inflation. But I also thought, I'm an experimentalist, so I build things in a lab like Yvette does, and so I was tempted to bring down from UCSD some experimental subject matter to actually study free will in real time. But then I realized, these are my grad students, And... I realized grad students are an existence proof of entities that have no free will, okay? So at least we know that there are entities that don't have free will. Maybe there are entities that do. So, again, I'm sure you still want me here, okay? So, Lev Landau, famous Nobel laureate once said that cosmologists are often in error, but we're never in doubt, okay? It's kind of a pejorative. He really didn't care very much for the dominant cosmology of the 40s and 50s, which was really, they should have been quite in doubt. And, in fact... That's the most pleasant state to be in as a cosmologist. You don't understand what's going on. It means you're likely to have employment the next day because there'll be so many more mysteries to understand about the universe. Then I thought about, well, what do these consciousness mavens think about consciousness? And so here's Daniel Dennett. He said, are zombies possible? They're not just possible, they're actual. We are all zombies. Nobody is conscious, not in the systematically mysterious way that it supports such doctrines as epiphenomenalism. And then he puts an asterisk, he'll be completely desperate to put this without context. So I've actually quoted the part that shows how desperately unintellectual I am. But it seems to me you guys that study consciousness are often in doubt, but maybe you're not in error because some of the things that you're predicting Maybe, you know, flexible enough to accommodate a whole host of alternatives. And that's why the theme of tonight is going to be, or today, this morning, see? I'm still on last night's clock as an astronomer. I, you know, wake up early in the night and work all night. So I want to talk about the experiments that we do and how they falsify models, how they prove models wrong. Yvette talked about exploring models and maybe proving things. I like to think about the experiments I do as kind of the ultimate in disappointment. I'm a disappointment to many, and I hope to potentially disappoint Roger himself because I'm looking at the potentiality of falsifying his otherwise beautiful, mathematically elegant theory, and we haven't done it yet, but it's always interesting to look at what can be falsified, and I think that winnows away a lot of the non-scientific things from scientific things. Okay, so then I googled what's the most complex thing in the universe, and what do you find? I'm like, six billion pages in 0.6 seconds, and it's the brain, okay? So it says the brain is the most complex structure, and you can do this experiment yourself, all right? So I studied the known universe, and I would agree, I would agree the brain is probably the most, but I don't know that much about it, so that's why I'm here today to learn from you. I'd like to start now with some exercise, some physical activity. So I've shown up here that one of these pictures is a picture of a synapse, and the other is a picture of a simulation of cosmological energy and matter and their behavior after some amount of time. I want you to raise your right hand if you think that this simulation on the right represents the universe, or raise your left hand if you think the simulation on the left So, raise your hand if you think the right side is cosmology, raise your left hand if you think the right side is really the brain and synapses, raise your left hand, and raise your hand if you don't like raising your hand, because you've got to get exercise. So the point is you really can't tell the difference. And I didn't game this. I mean, this is really, these are real simulations. This is the Millennium Simulation on the right. It's the universe. And then it's a simulation of what a brain cell does during neural activity. Here's another thing that shows, at least superficially, that there's similarities between the cosmos and the conscious mind that inhabits our skulls. So on the left is an fMRI, and on the right is a CMB, a Cosmic Microwave Background Map. They look pretty similar, right? And people make all sorts of extrapolations from this, but it's kind of like a parlor trick, right? It doesn't really have any deep meaning to it. A lot of things can look the same, but act very differently. But at its heart, what's so interesting to me is that the brain, in some sense, should be thought of, in some sense, as a type of computing instrument, and computers have aspects of them, as does the brain, that rely on ordinary physical, biological processes. Chemical processes are mediated not by quarks and gluons, they're mediated primarily by electrons and ions. That's just chemistry, and chemistry, I shouldn't say just, but it's chemistry. Chemistry, Dirac said, is basically a consequence of his theory of high-energy particle physics. And so, therefore, are the laws that govern the electrical connectivity in the brain, are those amenable just to simple application of Maxwell's equations? And that's the, you know, they haven't really been supplanted, except at the quantum level. And we know a lot about quantum electrodynamics, the most precise theory. In comparison to experiment that humankind has ever developed. With a theory and experiment agreeing to something like 14 decimal places. So even if it is quantum, we still, there is still some serious hope that we could actually investigate this using the tools of physics that we employ in laboratories and in our brains as we do study these things. Here's applied Maxwell's equations. This is an old 8036 microprocessor chip from Intel. There's a wiring diagram. Here's a fraction, a tiny fraction I got from Nick Spitzer at UCSD. A very well-known neurobiologist of the connectome, which is a map of how different processes in the visual system connect to one another. It's color-coded, and you can't read it, and even I can't read it up front. But the idea is that, look, these things look the same, and maybe at the heart have the same underlying phenomena at work, Maxwell's equations, maybe even quantum mechanics, that's okay. But should they be amenable to study using the laws of physics? And I'd like to think the answer is yes, but of course many of you are much more expert than I am. So, when you think about these things, when I talk to a non-expert, they always want to know things about the soul, the spirit, the self. So, I helpfully found this diagram here, okay? So, that's where you are. I don't know where that is, but it also looks a lot like the cosmos, doesn't it? And then, if you want a slightly bigger perspective, we can zoom out a little bit, okay? So, it's really depressing to me that probably 99% of you guys in the audience You know, cannot find where the Earth is on this plot. Okay, that's depressing. Okay, you can't see it. So this is meant to represent the Milky Way galaxy. It's not a real picture. It would take too long to get out there. But what I'm going to talk about today is not the stars themselves necessarily, but the space between the stars. I'm going to start talking about that, the emptiness of space that appears empty, but is not so empty in many different ways that have great consequences to the study, at least of the implications of cosmology and early universe physics on the way the deep future may evolve, and potentially on the notions of free will, Boltzmann brains, and things like that. So that's the motivation. So let's take a cosmic ego trip. Yvette talked about the opening of this glorious new epoch. We are like Galileo. We're living in Galileo's time, I should say. And that Galileo opened up the heavens to the investigation of astronomical phenomena using his eyeball, his refractive telescope in his eyes, connected to a telescope tube he called a perspicillum that gave him perspective, telescopic vision, distant vision. And he used this, as is well known, To overthrow the pre-Aristotelian doctrine that the Earth was the center of the solar system, which was effectively the universe to the ancients. So in doing so, he created a great deal of controversy. And the way that he did that, he actually didn't... Prove Copernicism. That's a fallacy to believe that he proved Copernicism. What he did is he showed that there's not one unique center to the solar system. By observing Jupiter and observing the phases of the planets. So there's some phases here. This is Venus. Exhibits phases. And they can only do so if it's closer sometimes to the sun than the earth is. He showed that, you know, Saturn has these weird ears. We now know what those are. But the key, the clinching evidence were his observations of the planet Jupiter. And he did something that I do to this day. He named an astronomical discovery after the donor that funded his experiment. Okay? So he named these satellites, he named them the Medici stars, after Cosimo de' Medici, who was his patron, essentially. He was his National Science Foundation. And with this theory, put forth originally evidence only in the visual form in Siderius Nuncius, a great book, Yvette, you should get it from your son before you leave, I'll give you a copy, because this book really just laid out visual evidence. And later on, the dialogo and the dialogue on two world systems. Then he laid out the evidence for heliocentrism. And that's really what got him into trouble and got him put before the Holy See, which is the Inquisition, basically. But this is a wonderful book, and it's worth a read. It's really the first scientific text of its kind. He's the first astronomer. He also did the first measurements on what's called relativity. And he was really... Driven by a passion to falsify the Aristotelian theory. Not prove his own theory. And that's where you get into danger of what's called confirmation bias. So he constructed a universe that's centered on the sun with the known planets that were known at the time. Notice we name the days of the week after these planets. And astronomers had done that for years, and it was only until later, when Herschel discovered the planet Uranus, that there came this question, do we add another day of the week for Uranus? And some people aren't comfortable pronouncing Uranus, you know, they do it the wrong way. So they didn't add another day to the week, but nevertheless, this was the new solar system, which effectively was the universe, no longer centered on the Earth. Matching observations, falsifying previous models, not proving it, but motivating it. I challenge you to think about how you could prove that the Earth is not the center of the solar system, not prove that the Earth is the center of the solar system, or prove the sun is the center of the solar system. It's very difficult to do, but actually it can be done, obviously, or we wouldn't know about it. Galileo did many things, but he was not immune to the pernicious effects of what's called confirmation bias. And that he had a theory now that he wanted to motivate in greater depth. So he looked at everything through the lenses, if you will, of the Copernican theory. And he looked wherever he could find evidence of Copernicus' model being correct, and he even fit some things to that model that were incorrect. So everyone's heard of Einstein's biggest blunder, although some say it's apocryphal and made up by George Gamow as sort of a joke that he said when he added the cosmological constant. He called that my greatest blunder. It's not clear. There's a book by Mario Livio called Brilliant Blunders that debunks that particular myth. But nevertheless, heroes make mistakes. Einstein makes mistakes. Galileo made mistakes, and here it is right now. I'm going to give to you what I think as an astronomer what his biggest blunder was. And it's a pretty good one. If I'm lucky enough to make the blunder that he made, I'll be quite excited about myself. So this is a constellation, a fraction of a constellation called Asterism. It's called the Pleiades. If you're Japanese, you'll recognize it as Subaru, which means the united. And they're united because they kind of look like they're all clustered together, and they blend together in a milkiness. And it appears to the eye like a milkiness. So soon after Galileo sketched the moons of Jupiter and the phases of Venus, he sketched what the Pleiades looked like through his perspective tube, through his telescope. And what he did was beautiful. He illustrates just by drawing. What the graphical, in graphics, what the physical perception was in his mind. How did it feel to experience looking through these stars, looking at these stars through his telescope? He did that on the cover of Sediris. And then he says, you saw the big craters that don't really exist on the moon, but it's the perception that mattered to him. Because there wasn't a worldwide web. He only printed like a hundred of these things. The ones that exist today are mostly fakes. But what he shows here, In the stars of David, these open stars, those are the six stars, they call it the seven sisters, but really only six stars are particularly easy to see. These stars of David, these open stars, are stars that you can resolve with your eye, that you can see without the aid of a telescope. But with the aid of the telescope, you can see innumerable stars, all these black filled in stars. Those were stars you could only see through a telescope. So what he says down here is, what was observed by us is the nature or matter of the Milky The Milky Way itself. With what the aid of the spyglass may be observed so well that all the disputes that for so many generations have vexed philosophers, I love the way he teases philosophers, as all physicists do nowadays, are destroyed by visual certainty, and we are liberated from wordy arguments. So he's saying visible certainty. The eye connected to the brain, and the visual connectome, that can prove things in physics. It's amazing. Unfortunately, evocative as these diagrams are, They're not correct, and this led to his greatest blunder. He claimed, this is the Hubble Space Telescope, looking at the Pleiades, at this nebula. And it turns out it's a nebula, which is Latin for cloud. And he thought the nebulosity, he was saying the nebulosity was just many, many stars that he could not resolve with his limited-size telescope. It was only about an inch and a half in diameter. So he said, if I had a bigger telescope, which he went on to build, but he said, if I had a much bigger telescope, I'd see this fuzzy milkiness, and that would be the actual stars that I couldn't resolve before, just like this one, this one, and this one are. So in his desire to show that stars are just like stars like our sun, and the whole Milky Way is made up of stars, he committed a blunder. Again, not a great blunder, but if you zoom in on these, On this star down here called Merope, this lower star here, and you zoom in on it, you see now with the aid, if you happen to have a Hubble telescope lying around, you can now know that this is not ever going to be resolved into stars. In fact, there's no stars here at all, really. But what is there is dust. And dust reflects the light of Merope like little tiny mirrors. And what is the dust? The dust is... Reflecting the twinkling of the star and it's primarily composed of iron and nickel and I brought some here That will be my gift. Oh, yeah, it's basically like this much smaller versions of this. It's a meteorite It's an iron nickel meteorite and the other things that are inside of that nebula are these things which if I found it I had it. I got it off my three-year-old this morning. It's a piece of dust Okay, it's easy to find I'd like to do laboratory experiments with my kids So it's a piece of carbon, but actually it's a much purified form of carbon. They actually believe that the carbon in there is in the form of diamond, pure carbon, allotropically pure carbon. So that's a diamond in the sky. Isn't that cute? But what happened to that diamond dust? So that diamond dust, I claim, is us. This is a famous picture taken on Valentine's Day 1990 by the Voyager spacecraft. Carl Sagan turned the spacecraft around, pointed it at the Earth. Now, where the earth would be, and can you see it? Isn't it beautiful? It's a beautiful self-portrait. No, I can't even see it up here. I circled it here. This image was called A Pale Blue Dot, and he made this beautiful poem that went along with it. He said, we succeeded in taking that picture, and if you look at it, you see a dot. And then he goes on with beautiful prose. He says, that's here, that's home, that's us. Every saint and sinner in the history of our species lived there on a mote of dust suspended in a sunbeam, just like we saw with Merope. So dust is real and the dust becomes us. This is the planet suspended in the sunbeam just as it was for Merope. Now, in the 1700s, the successor, the heir to Galileo was William Herschel, a proper British gentleman who had an enormous telescope, the 40-foot telescope in the countryside of England. He made a map of the galaxy that basically overthrew the Copernican revolution that Galileo had ushered in. He put the sun at the center of our Milky Way galaxy. What he didn't know is that he was being deceived by dust. Dust attenuates the view in all directions and makes it appear that stars which are close by in different directions are actually much farther away than they are. And that optical illusion is a mirage for we are nowhere near, as you saw in the beginning, we are nowhere near the center of the galaxy. Tens of light years, of thousands of light years from the center of our galaxy where a giant Milky Way galaxy spirals around a black hole, the mass of several million stars. And that was discovered by Herschel and Curtis, and then Curtis and Slipher and Hubble actually disproved that we're the center of the galaxy. Now the question today is, are we the center of the multiverse? So to talk about the multiverse, I have to talk about a different type of telescopic evidence. So we see light, as Yvette said, we see light primarily since Galileo and our telescopes. But it's not all light that we can see. Some of the light we see is invisible, or we detect is invisible in the form of microwaves. This is the famous cosmic microwave background radiation, roughly 3 Kelvin thermo blackbody signal that arrives to us in all directions, almost uniformly perfectly. So Penzias and Wilson measured this in 1965 and they won the Nobel Prize about 13 years later. Nowadays we can measure it, and if you were looking out on the earth, this is what you'd see. Primarily, you wouldn't see any variation from this orange glow. So the question is, as Newton posed hundreds of years before Penzias and Wilson, in a universe of infinite perfect uniformity and homogeneity, how did clumps of matter come to form where they did? There's nothing that breaks the symmetry. So, roughly speaking, for hundreds of years we've been toiling under the assumption that the universe is too smooth for us to be asking questions as to why it is so smooth. So it's sort of a paradox. Later, we were able to see as the galaxies and matter evolved throughout the universe, these dust grains collided and stars formed. This is the Hubble Deep Field. It's an image with about 5,000 galaxies in it. And if you take the size of this image, which looks big to you, but really it's only the size of this laser pointer spot up here if you go out in the sky and look at it. So if you take all these 5,000 galaxies, they're all compressed into a laser pointer spot that big. So how many total galaxies are there in the observable universe? All we have to do is count up those number of laser spots it takes to cover the whole sky. So we've got 15 minutes. No, I'm not going to do that. If you do that, you get about 100 billion stars. 100 billion galaxies, 100 billion stars in each galaxy. So it's remarkable. We think now that there are fluctuations. We don't know where these fluctuations came from. So we think that gravity pulls in the matter. The early primordial hydrogen and helium were the only materials that existed. They coalesced in gigantic gravitational potential wells. When they got compressed enough, nuclear fusion took place and they could ignite and become stars. The stars live out their lives over billions of years and explode and they spew out into the interstellar medium surrounding them. They spew out chunks of rock and dust and iron. And that iron and rock and dust is what the earth is, if you think about it. So this process takes us from shortly after the Big Bang to today. But the question is, how did those clumps of matter know where to form in the first place? So there was no real good predictive theory that prescribed how that could happen. Until about 1980. So the cartoon you should think about is the Big Bang happened, then we see this CMB pattern, then stars and galaxies could start to form, and then we live in this present day today, 13.82 billion years after the Big Bang. But we care about what happened at time zero. That would be the most interesting thing as a cosmologist to unravel, and it has implications on the future of the universe and free will as well. So we can't go back in time any further using light. As we look back, it's like the unfortunate weather that we're enjoying during your trip to San Diego this week. We have June gloom has set in. So imagine that someone tells you a plane is flying overhead or there's an explosion of a firecracker at SeaWorld like there might be tonight or this weekend. Well, you could hear it, but you couldn't see it because the marine layer obscures your view. That's what the CMB is for us. We have to use another form of radiation. And it's similar to the waves of radiation that Yvette mentioned, namely its gravitational waves. But these are primordial gravitational waves, not short wavelength gravitational waves, the longest gravitational waves we believe would exist. And if you do that and you see them, you would know that a process called inflation took place. I don't have that much time to talk about inflation, but I'll give you the cartoon version. The universe we see today at about this image results from a time when the universe was about 400,000 years old. To put that in seconds, it's about 10 trillion seconds after the Big Bang. Sounds big, it is big, 400,000 years, but it's not infinite, it's not really enormous numbers. Now what we want to do is go back in time to the first fraction of a fraction of a second after the Big Bang. In fact, we want to go back with inflation to the quantum universe, where it's purely quantum gravitational, and that's at an epoch of about a tenth of a trillionth of a trillionth of a trillionth of a second after the Big Bang. We believe at that point the universe can't be described by classical gravity and must be quantized, and we don't have a good theory for that. But if there were this fictitious field called the inflaton, or unknown, undiscovered field, I should say, then it would be like doing the following. Some of you are biologists. If you were to look at this object here, you could tell me what it is. Does anybody know what it is? Anybody need any more coffee? It's a blastocyst. Stuart got it, I think. So the blastocyst represents the way the human embryo looks at about 1,000 seconds after conception. I won't get any more graphic than that. Okay, so about a thousand seconds after conception, this is what you looked like. Now, tell me, if you could look at this object in the future, what would it look like? Well, I'll help you out. I'll put some hints on it. So if I put some hints on it... Okay? Now look here. Stuart, I took some liberties. I guess you're about 2 billion seconds old. It's about 60 years old, 59 years old. But 1,000 seconds to 2 billion seconds is a factor of 2 million in time. I'm talking about 50 orders of magnitude in time. It's much, much harder to do that. So we believe that inflation happened. This is a cartoon you should keep in your mind. If inflation happened, gravitational waves were produced. Those gravitational waves would make a specific pattern on the cosmic microwave background radiation called polarization. So the polarization has a couple different forms, I won't get into great detail about it, but it's just like these polarized lenses here, these polarized, um, polarizers here. Like your sunglasses that you would use on an ordinary San Diego day. Come back in July, come back, visitors bureau asked me to say that. So these polarizers, when they're at right angles to each other, they obscure all the light, and that's the way your polarized sunglasses work too. So we have to build a polarizing perspeculum. We have to build a telescope that can see things because our eyes are only very, very weakly sensitive to polarization. So I call this part the sixth sense portion of the talk. Now, it's not the sixth sense in the form of this fantastic movie. But it is the sixth sense, which resides in a fraction of the human population, can actually distinguish polarization naturally. And it's due to a remarkable aspect of our eyeballs, which are, as I said, little telescopes. So if you put a filter that polarizes in front of a telescope, you get a polarimeter. And that's what's used to measure these gravitational waves. But in your eye, you can actually do it. This is a phenomenon called Haydinger's brush. What I'm going to do is I'm going to remove this pattern instantaneously. And when it is removed, your eye, sometimes, if you have the sensitivity, will still see the persistence of this pattern. And that's due to the fact that this pigment inside your macula, and Eric Beery knows way more about this than I do, called xanthophyll, has a little bit of dichroism to it, a little bit of polarization asymmetry to it. So I'm going to remove the words. I'm going to remove the pattern. And raise your hand if you still see the pattern after I remove it. I'm removing it instantly. I'm not playing any tricks yet. Sometimes I see the opposite of the pattern, like the inverse of it. I see yellow where it was blue and vice versa. I'm going to take it away again. Anybody see it? Yeah. A fraction of the population can see this. We don't have the ability to see light with our telescopes, we need to see microwaves. So we built a microwave for speculum, which is a short, really small telescope. It's only about five feet tall. It's called BICEP-2. It uses very advanced detectors called superconducting transition edge sensor volometers, and they're coupled to squid amplifiers. I've got them up here and I can show you guys later if you're interested. This telescope focuses microwaves that are polarized. From that we make patterns of the sky as you would see them if you could see polarization of microwaves. Here's what it looks like on its mount, about 10 feet tall, weighs about 10,000 pounds. It has its own Twitter account, like everything has to nowadays. We took it to the South Pole in 2005. We installed it in the second most important building at the South Pole. And there we observed, and we're actually the longest continuously running experiment down there. We've been running non-stops since 2005. Now it's 2017. I'm quite proud of that. I've been there twice. And we measured a pattern that was consistent with the pattern you'd see if gravitational waves existed. And we got a lot of attention for it. It was on the front page of the New York Times. An even better newspaper called the San Diego Union-Tribune. Pick up a couple copies. We also featured it. The Economist had an article, which I like, because it says, man suddenly sees the start of the universe. So like some guys, whoa, the universe. Wow, that's awesome. Now, the question is, did we see what we saw, what we thought we saw? Or did we confirm a deeply held bias, potentially? And it turns out, unfortunately, it was the former. We were looking for a pattern. The signal looked just like the pattern we'd see, but we didn't know about the interstellar interloper dust at the time. There were no maps ever made of the sky at these frequencies. When we looked at the signal produced by dust and subtracted it from our data, the signal went away. So it actually burst this bubble that would have confirmed the existence of inflation. So that was disappointing. Here's just some images that I'm making about it. And I'll skip over those. Now, the question is, how can we improve the measurements we're making of inflation to go deeper, to falsify it, or to prove it, or give evidence, I should say, rather, for it? So one way that we do it is our polarimeter BICEP2 is only sensitive to a single frequency, and to measure dust and the CMB you need two frequencies. So we're now, with my PolarBear collaboration and Simon's ArrayCap collaboration with UC Berkeley, we're now building detectors that are intrinsically polarization sensitive and can measure two frequencies simultaneously. And that would help us instantly rule out the presence of dust. This is what the telescope looks like. It's much bigger. It's a Newtonian reflecting telescope, not a Galilean refracting telescope. That's in Chile. One last thing is about other pieces of evidence. Some people have claimed that you could spot the presence of another universe via a collision with our universe at early times, and that would then create a specific pattern of the CMB on the sky. And I give a little demonstration of this in a talk I gave for TEDxSanDiego a couple of years ago. But the question is, in the multiverse, is it too crazy to be true? Because what it really predicts, I'm sure Sir Roger would say yes, what it predicts is that there's basically a functionally infinite number of universes. Greater than 10 to the 80th or 100th, 10 to the 100th, Google universes means that there effectively could never tell a difference between that and a truly infinite set of universes. And that's called the multiverse. And it seems to be not only a prediction of inflation, but almost impossible, unavoidable, irreducible property of it. You can't get rid of the multiverse. So if you detect inflation, evidence for inflation, that mandates that we live in a multiverse. That mandates that there's probably 10 to the 500th or more universes that are not Some that are not this similar to ours. Some that are exactly identical to ours. They're having this conference right now in a place called La Jolla. Some are having it in a place called La Jolla. Okay? And then some don't exist for very much longer than a nanosecond. So these universes can span a tremendous spectrum. The laws of physics can change. What does that do to the very notion of falsifiability in a universe where anything goes? That's a big problem. So there are other alternatives to Roger's proposed one. My friend Paul Steinhardt and Neil Turok proposed another one called the Ekpyrotic Universe. I won't talk about these, except to say that they're cyclic. The problem that a lot of astronomers have always had with the Big Bang is that it implies a big banger or a beginning. And in fact, in the beginning, a lot of people were more attracted to the steady state model, which the CMB discovery falsified. And that was true because most cosmologists, like most people, are secular, and they... Found the notion of a single creation abhorrent. Now, I don't know if that influenced Sir Roger, but I know that many scientists prefer cyclic or eternal cosmologies because they avoid this question of what happened in the very beginning. Second problem, and just an homage to the other great film besides Anchorman that was filmed here, Free Willy. Okay, so what does this have to do with free will? Well, what if I told you that there's an infinite number of universes? Infinite, not just a big number, not 20, not 500, 10 to the 500, or more. How would you know that you are you? That the perception of your own identity is really you? How I wonder what you are. How do you know what I am? So I've picked up two pictures of Stuart. Now who thinks, raise your hand, I don't care which hand, raise your hand if you think that these pictures are the same. Raise your hand. All of you think that they're a different picture. I've definitely flipped them around, I'll grant you that. But they're actually different, I put a little less twinkle in one of his eyes. I don't remember which one, but it's the same eye on both sides. Okay, so how do you know who you are? Why do we perceive it as who we are if there's an identical copy of this exact conference going on an infinite number of times? Infinite, not just once or twice. That would be scary enough, right? Okay, so the last things I want to say about the controversies in cosmology and consciousness seem to be parallel. They both have this question of origin. Explaining their own origin is very tricky in cosmology. And in the multiverse hypothesis, an eminent theorist, Paul Davies, he wrote that multiverse explanations are reminiscent of theological discussions. They invoke an infinity of unseen universes to explain the unusual features of the ones we do see. They may be all dressed up in scientific language, but in essence, they require the same leap of faith, faith being anathema to scientists. So that's a problem, and it's creating a great controversy in physics today. Last thing I want to talk about, I just have a couple of minutes left, are Boltzmann brains, since the brain conference is the last problem. It seems to be inevitable that in most models of inflation, even without the multiverse, forget about the multiverse, that you get these organisms called Boltzmann brains, which they claim, you know, this statement here, where Boltzmann himself said in 1895, there are regions of the universe where there could be fluctuations, which he calls a galaxy, a whole world, in which consciousness and sentience could evolve. This was claimed to be a consequence of many models of inflation. So Sir Roger asked me to show a picture of a Boltzmann brain, so there you go. Very accurate, detailed, scientific representation of a brain in a circle. But a Boltzmann brain is a hypothesized self-aware entity that results due to a random fluctuation, and it's due to the organizational principles that are more likely to occur for simpler structures than for more complex ones, as Sean Carroll's slide I stole from him. Now, there's actually what I call Boltzmann Lobotomy, because you can get rid of it in inflationary models, it seems to be inevitable, but Sean and his colleagues have actually gone through ways to get what's called De Sitter inflation without producing Boltzmann brains. So I call that getting rid of the Boltzmann brain as Boltzmann Lobotomy. So the last slides I want to talk to you about are just the consciousness controversies that I see paralleling and echoing the debates we're having in cosmology. Just as the appearance of something out of nothing can be explained by our saying that the first something was very small, cannot be explained by that, the birth of consciousness is rendered no less mysterious by saying that the simplest minds have only a glimmer of it, speaking to the complexity of it and dressing things up in the seeming scientific language. Perhaps the emergence of consciousness is simply incomprehensible in human terms. Every chain of explanation must end somewhere. It's reductio. Consciousness might represent a terminus of this sort, defying analysis. The mystery of the inner life of the mind may one day cease to trouble us. I'll just sweep it under the cosmic rug or the conscious rug. That's depressing. So I want to leave you guys with a gift. So how many of you have ever received a star or bought a star for somebody as a gift? Raise your hand. Okay, you should be deeply embarrassed. Shame on you because... These stars actually don't mean anything. I never look up and say, oh, there's Ron Johnson's star, yeah. No, we don't care about this as astronomers. But these guys are smart, right? They not only will sell you this star that no astronomer cares about for $99, but for an extra $14.95, you'll get a chart that shows a picture of it. So, okay, it's a pretty good deal. So I thought, well, in Roger's cosmology, there's an infinite number of aeons that preceded us, so why not sell off a couple of these aeons? What's going on? We started our own business and see us after the discussion. So I just want to leave you with hopefully some motivation why you invited me and why I could go over by a minute. Is consciousness intrinsic? Yes. Is it something that's in the universe? That question I didn't answer, but I did talk about evolution of life via how dust became us, how Boltzmann brain processes might work or are inevitable consequences of cosmological models at the cutting edge, and do we have free will? That question intimately relates to the multiverse. And I conclude by saying it's not brain surgery, it's only rocket science. And I just want to say that for me as a scientist, as an experimentalist, I like to go out and measure things. So Feynman used to say, shut up and calculate when theorists would worry about the abstractions of their theory. As an experimentalist, I'm blessed with the ability to go out and do measurements that have consequences on these wide-ranging things, even outside of my particular expertise in cosmology. And I'll leave you with the words of the immortal Mahatma Gandhi. He said, the seeker after truth should be humbler than the dust. The world crushes the dust under its feet, but the seeker after truth should so humble himself that even the dust could crush him. Only then, and not until then, will he have a glimpse of truth. So dust is often overlooked, but should be never doubted. Thank you, guys. I present to Stuart. A piece of space dust, and a token of my appreciation for being here. I was hoping for an eon. Thank you very much. I will treasure this, actually. Is there any evidence for inflation in the multiverse? So the inflationary evidence, if you were to see inflation, a lot of people claim that there's inevitable link to the multiverse. You can't avoid the multiverse hypothesis. In other words, inflation takes place in this enormous petri dish. We call it the multiverse, and each individual colony or cluster or culture of bacteria has its own perception of being a unique universe, but until they come into contact, they don't actually know the existence of others. Is that a yes? If inflation is correct, the multiverse is correct. Is there evidence for inflation? So we currently have zero evidence for that inflation is guaranteed to occur. We have evidence that can potentially falsify the alternative models, but inflation is very flexible, and it may not be possible to falsify inflation. So I can't say it's not correct. I can just say we don't have evidence that leads us to inflation that's beyond a reasonable doubt, circumstantial level. Okay, I don't know if Roger wants to comment, but I think he would disagree with that. Do we have any questions?