#science #physics #ideas The Biggest Ideas in the Universe | 21. Emergence

#science #physics #ideas The Biggest Ideas in the Universe | 21. Emergence 95,385 viewsAug 11, 2020 1.7K DISLIKE SHARE DOWNLOAD CLIP SAVE Sean Carroll 154K subscribers The Biggest Ideas in the Universe is a series of videos where I talk informally about some of the fundamental concepts that help us understand our natural world. Exceedingly casual, not overly polished, and meant for absolutely everybody. This is Idea #21, "Emergence." None of us is Laplace's Demon, so how are we able to successfully model the world even though we have incomplete information about it? The answer lies in the existence of higher-level patterns that emerge in the right circumstances. Special emphasis is placed on the emergence of a classical world from quantum mechanics. Hyperion tumbling animation: https://www.youtube.com/watch?v=tk8r8... My web page: http://www.preposterousuniverse.com/ My YouTube channel: https://www.youtube.com/c/seancarroll Mindscape podcast: http://www.preposterousuniverse.com/p... The Biggest Ideas playlist: https://www.youtube.com/playlist?list... Blog posts for the series: http://www.preposterousuniverse.com/b... Background image: Auklet flock, Shumagins 1986, by D. Dibenski, https://commons.wikimedia.org/wiki/Fi... #science #physics #ideas #universe #learning #cosmology #philosophy #emergence 261 Comments rongmaw lin Add a comment... Sean Carroll Pinned by Sean Carroll Sean Carroll 1 year ago Erratum: As a couple of people have pointed out, there should be an additional factor of the complex conjugate of the wave function in the expectation value formulas 48:00. See e.g. https://en.wikipedia.org/wiki/Expectation_value_(quantum_mechanics) 38 yak yak 1 year ago Drawing a rough oval shape and saying "so, here's reality" is probably the coolest move a person can make. 86 Too Crash Too Crash 1 year ago (edited) "Something Deeply Hidden" Dr. Sean Carroll, will be in my book collection, thank you so much for training us. ❤ 22 Gabriel Q. Gabriel Q. 1 year ago When he does "silly things" is a reminder for us that he's human after all. Love from Chile. Thanks for being such an amazing educator. 35 Paul C. Paul C. 1 year ago (edited) A little after 4 pm here in Wales, and I just got back from a visit to the Dentist. What better way to take one's mind off sore teeth & gums, than a new episode of Biggest Ideas with Doctor Sean. Thanks once again Prof. Carroll, for making the World a better place - or one of the Worlds, anyway !! 25 Alexi Liera Alexi Liera 1 year ago Yay! Thanks, Sean. You absolute rockstar. 25 PROF. Golden Gadzirayi Nyambuya PROF. Golden Gadzirayi Nyambuya 1 year ago Thanks for the latest video --- I guess you must consider penning a book entitled "The Biggest Ideas in the Universe", with each video being a chapter, or series of smaller books with each book covering a single video! 9 Bohan Xu Bohan Xu 1 year ago I really wish advanced undergrad physics class include information like this. I think it's almost always worth it to have a basic understanding about how the subject of interest fit in to a bigger framework of physics 4 Jainal Abdin Jainal Abdin 1 year ago Question for Q&A: Regarding emergence, is spacetime something that needs to emerge from quantum gravity, or can it be skipped as long as you can describe its results? Dave Wilson Dave Wilson 3 months ago I love watching and learning this stuff. Really appreciate your videos my man! Just Data Just Data 1 year ago Thank you Professor Carroll for a wonderfully informative series. My question is (I have many but I'll settle with this one): Are there any hypotheses down the lines of the reason for emergent properties/theories being possible because of the necessary fussiness of quantum mechanics (QM) measurement? Or put another way, are there hypotheses that map the apparent necessary ambiguities of QM to existence emergent properties or theories? Or, in the broadest sense, are their any proposed ideas (from scientists, I'm sure philosophers have many proposals) at all on reasons for the existence of emergent properties? Erik Erik 1 year ago Your self-criticized writing while talking has improved over the course of this series. It shows here especially. Been hooked since the beginning, and I'm always looking forward to new releases. Keep em comin! 2 Iouri Iouri 1 year ago Hi Sean, thank you so much for your lectures, I don't understand some but when I read books some of your ideas click and make more sense. Lew Kor Lew Kor 1 year ago Another super-duper video ;-) Love all that you do Sean! Empathy is only human Empathy is only human 1 year ago I believe it was on an episode of Veritasium that a theory proposed in a peer reviewed paper says that, and I'm paraphrasing here, that life if an emergent property of entropy. The idea being that in the aggregate, entropy is more efficiently increased in the presence of life as opposed to the absence of life. If we look at the floor of a forest, the immediate impression is one of disorder, or to rephrase that, in a state of high entropy. Where as if you review the photographs sent back from mars via the various rover missions. The surface of the planet seems to be in a relatively low entropic state. For me this was a very important revelation as I've been wondering for several years now as to what property of the universe it is, that provides the needed systemic or environmental pressure so that life might emerge naturally upon a planet where the building blocks are readily available. We know also that our universe is expanding. And that this expansion is accelerating. Is it possible, that entropy is a naturally emergent property of that expansion? Measurement of that expansion has been rated at so many meters per megaparsec per unit of time. However, it seems to me that the only measurement we could actually produce a quantifiable acceleration is the acceleration experienced by normal matter we can observe. It seems only natural that spacetime, the fabric in which all matter resides, must be expanding and flowing past all the stars, planets, galaxies, etc. At a velocity that enormously dwarves the velocity we observe galaxies travelling outward from the center of the universe. An analogy to this would be a large object being moved slowly down stream by the rapid waters of a river. With only the compression or deformation of spacetime via the presence of celestial bodies of matter. Creating a kind of drag upon spacetime, that naturally transfers some of its kinetic energy to the normal matter of the mass in the universe. If this is true, then we have an answer to what dark energy is comprised. Additionally, we know that when massive objects travel through spacetime that the greater the difference in velocity the more massive the objects become. This is general relativity at work. So if spacetime is flowing past us, then does this not also suggest an answer to dark matter? As spacetime flows past galaxies, so to do the mass of neutrons and protons increase in a corresponding measure. This increase in mass being explained via the manifestation of quark/antiquark pairs within the structure of matter. Thus while locally the differential would be too miniscule to effectively measure, in the aggregate it all adds up. Thus making dark energy, dark matter, and entropy emergent properties of our spherically expanding universe. And yes I am aware that certain assumptions are in place in this description upon which we as of yet lack clear consensus. And there are additional ideas I've been kicking around lately concerning the interior of black holes, the big bang, our eventual heat death, and the ways in which multiple verses (as opposed to a universe. Differentiated from the multiverse idea by way of other verses not overlapping our own) eventually interact via massive gravitational waves which might be described as spherical shockwaves traveling outwards for all time. Eventually, if any other verses do, or have existed and have also experienced heat death, might not the interaction of these shockwaves produce ring verses of much smaller scale than our own universe? In other words these shockwaves intersect each other, and if in the aggregate there is sufficient energy, then perhaps torus shaped verses are the predominant form of verse formation. If this were true, and there were a sufficient number at a high enough density, then the overall universe might be something far more akin to the patterns we see produced on the floor and walls of a swimming pool when light shines through the waters surface and there are enough waves to produce seemingly random peaks and valleys. If this view of the universe at large is correct, then it also suggests an answer to the nature of the big bang. Within our uniformly expanding universe, newtonian laws of physics provide a means for the limitation to the amount of material any given black hole has access. This model however would be invalid in the swimming pool analogy. Suppose if you will that we have the presence of a black hole, in the relatively chaotic system of peaks and valleys, such a black hole might rarely have access to incredible amounts of matter upon which to feed. Presuming that such a black hole could feed until approximately an equivalent amount of energy to that present in our current universe. Then perhaps, via some mechanism this could produce an event such as the big bang. Just my thoughts and ideas on the larger picture of the cosmos. I hope you enjoyed reading this narrative. #endhatrednow 3 kees broenink kees broenink 1 year ago This is such a great series and this episode is very very helpfull. Thanks a lot. 1 Quahntasy - Animating Universe Quahntasy - Animating Universe 1 year ago Love these series of Videos. Absolute masterpiece 2 Olivier Loose Olivier Loose 1 year ago A question: As quantizing both the classical theories of Sine-Gordon and Massive Thirring gives rise to a relationship between fermions and bosons in a single quantum theory, would there be any sensible connection to be made with supersymmetry, given that supersymmetry also reflects a relationship between fermions and bosons? Pascal Bercker Pascal Bercker 1 year ago Sean Carroll is really a philosopher who does physics! 2 James Nogg Nogg James Nogg Nogg 1 year ago Sean "never makes a talking mistake" Carroll. Perfect diction, tone & intelligence consistent over time in many, many informative cutting edge physics videos. Many thanks Ayush Raj Ayush Raj 1 year ago If you could talk about emergent gravity ( in reference to E.Verlinde's paper) in the Q & A session, that will be really great. Thanks in advance! Volaire oh Volaire oh 1 year ago Hi Sean, I've said it before but you are a legend for doing these, they have really helped me through this difficult time and I'm sure I'm not the only one.. I haven't been able to afford to pay yet but am buying your books 🙂 6 Smitty Smitty 1 year ago What a coincidence, two days ago I was talking to some friends about the nature of consciousness; arguing that I truly believe it is an emergent property of living matter. You mentioned consciousness briefly in this video but do you have any further thoughts on this? 2 Rhonda Goodloe Rhonda Goodloe 1 year ago Sean, thanks again for do this series! Liam McCarty Liam McCarty 1 year ago Is it possible to quantify or rigorously define how “simple” or “efficient” a theory is, maybe in terms of information? You didn’t explicitly mention Occam’s Razor but this seems implicit in the fine-grained, homeostructural category and maybe for the others too Michael Li Michael Li 1 year ago awesome video，compare to other too mathy ones, this one relatively easier to understand and very interesting soulremoval soulremoval 1 year ago Hi Sean! Love the idea of emergence. 1 Sewer Tapes Sewer Tapes 1 year ago This is the second time I've awaken from a bizarre, science heavy dream, to find Sean Carrol on my TV. John Długosz John Długosz 1 year ago Your opening remarks, about how having a certain complexity causes things to happen that you never would have guessed, is a perfect explanation of why software is so difficult. And it also provides analogy to your vocabulary shift to a chunked-state representation: we discovered "metafunctions" in C++ templates, which were designed to provide parameterized types for making strongly-typed collections and the like. Turned out to be a Turing-complete language that developed its own idioms. That's an extreme example of how we strive to tame software: make it in layers, to produce a hierarchy of complexity. It's so hard to explain how to write "good" functions that express a single level of complexity, and what we're trying for is just why "gas" is not wave packets: once you abstract over it, you need to stick to the items within the emergent description. 1 kimoothe1st kimoothe1st 1 year ago I am waiting for a video where you lay out the frontiers of large scale experimental and observational physics like LHC, extremely large telescopes, James Webb telescope, ITER, etc and what questions they will try to answer. David Hand David Hand 1 year ago This MT theory is so much more intuitive than the standard explanation for fermion behavior. Can I get some links? NoWhereMan NoWhereMan 1 year ago (edited) Thx again, you have single handedly filled some major gaps I had in my education as a Chem E in the 80s. I have at least a glimpse of how we have gone from the predicting the familiar world around to the very small which only can see by the tools we have invented. Since my job was to phenomenology predicting the behavior of dry etch plasmas, this knowledge would have been particularly useful. dePlant dePlant 1 year ago If starlings flock only by minimizing distance from and matching velocity with nearby starlings then this would entail weak emergence. But if each starling ALSO flies towards the darkest area of the flock, then wouldn’t this mean downward causality from the flock to the individual bird mean this represents strong emergence? Luiz Tauffer Luiz Tauffer 1 year ago Your didactic is superb, thank you Sean! Lyman Hale Lyman Hale 1 year ago Thanks for doing these!! Wonderful! 2 Michael J Morrison Michael J Morrison 1 year ago Very, very exiting, impressive and inspiring! If only i could keep up..... will need to get your books and papers and watch all the videos again and again. Thank you for carrying us to the edge of the known reality which we once would have thought was well over the horizon. Kind of like the 'Beginning of Infinity' heh! We are all in your debt even if not anywhere close to your depth. Down Under Felipe Reyes Felipe Reyes 1 year ago With respect to bosonization, the kinks and anti kinks seem to represent particles, but also excitations (at least in sine gordon where particles are changing state). Is it then useful to think about the kinks as quasi particles like phonons for example? And is this a different kind of emergence, when the collective behavior of interacting particles seem to create excitations that also look like particles? 1 Traruh Synred Traruh Synred 1 year ago I once played of MIT game 'space-wars' at Stanford coffee house in which there was a bug -- the force law was 1/r (measured it using ruler and watch) instead of 1/r^2 and one could not establish a stable orbit making the game unplayable. Orbits failed to 'emerge'. 1 David Ruiz-Tijerina David Ruiz-Tijerina 1 year ago I spotted a small mistake in minute 48:16. The formulas given for the expectation values of position and momentum (x-bar and p-bar) are missing the complex conjugate of the wave function inside the integrand (for p-bar, the derivative applies only to the wave function, and not to its complex conjugate). Also, not sure if hbar has been set to 1, but if it hasn't, p-bar should have a factor of hbar. Tunnelsloth Tunnelsloth 1 year ago I know you two are certainly not on the best terms, but just wanted to mention that on a recent podcast, Eric Weinstein praised you for doing this video series, Sean. (I don't really know why I'm saying this beyond the fact that I like you both.) vinm300 vinm300 4 months ago I've just finished Sean Carroll's book "The Big Picture", it is great. I'm viscerally opposed to Many Worlds, but Carroll speaks and writes better than anyone.(Perhaps bar Richard Dawkins) John Długosz John Długosz 1 year ago I think the idea of "strong" emergence is indistinguishable from the case where the microtheory is not accurate. It's incomplete somehow. Evolving it forward will give you an answer, but the real-world macro behavior is exquisitely sensitive to the exact behavior of the microtheory, so it doesn't match. The theories we _use_, on any scale, are "effective", anyway. A good simulation will not produce the ideal gas laws -- a poorer simulation would! I think you're right in that "strong" emergence is not possible, and any such observation is actually a clue to probing the physics beyond the microtheory being used. For sociology etc. I think the admission that it's not possible for us to do it because of measurements or computational load is what it actually stems from. Nathan Okun Nathan Okun 1 year ago You might want to call the "higher level" rules/laws/theories as "Meta-Laws/Rules". This is much like in chess: The rules governing the initial placement and movement of pieces is your "micro" laws and the basic concepts of strategy and tactics to actually play the game are the Meta-Rules. This keeps the two separate, since the Meta-Rules can vary in complex ways while the low-level rules are usually fixed/constant (speed of light, etc.;), as in chess. 1 Hrenopochta Jh Hrenopochta Jh 1 year ago (edited) I think when you're simulating interactions of MULTIPLE instances of micro objects, you're effectively simulating the whole macro system, and of course there's no reason of why you shouldn't be able to find all the properties of the macro\emergent system this way. I think the question is actually different: can you discover all the properties of a macro\emergent system by studying ONLY ONE it's micro object alone (you can even simulate it on a computer, but only one instance of it)? I.e. if you're only allowed to study or simulate a single atom of gas can you identify all the properties of the gas consisting of multiple atoms? Or similarly, if you're only allowed to study or simulate one ant can you discover the rules of the ant colony? Or with humans: if you can only simulate 1 human on a computer can you discover how social structures in human societies might work? - I think not. Again, I think when you're allowed to simulate multiple elements with their interactions, you're essentially simulating the whole macro-system, so of course you'll be able to discover all it's "emergent properties", but that's only because you already switched to studying the whole emergent system from studying only it's single components.. I.e. interactions is the key, and if you can only study\simulate one atom you can't discover the macro-properties of the material made from these atoms.. I think.. 1 Chris Stewart Chris Stewart 1 year ago In the Q&A video, could you talk about the difference of "throwing away" information vs "compressing" the information? As an example, is calculating the center of mass of the earth not compressing the information of all the individual particles? (vs. throwing that information away) 1 lukewormholes lukewormholes 1 year ago love your "who cares?" approach to the semantic arguments ppl love to get lost in Pillio Zoltan Pillio Zoltan 1 year ago Quasiparticles and theories which are using them are good examples I think. How the lack of an elektron could act like a partical and simplify the description of the system. Or an excitation could act like a partical. Or the excited electron and the empty lower energy state could act like a partical-antipartical pair. Chirality452 Chirality452 1 year ago What about General Relativity as an emergent theory of gravity where the standard model or an expanded GUT would be the micro-theory. Think of Sakharov's ideas on this. This gets around the pesky problem of quantizing GR by consider it as an emergent theory analogous to thermodynamics compared with statistical mechanics. The gravitational constant G would be derived from this micro theory and they gravitational field would be distortions of the quantum vacuum. In this concept gravity doesn't exist and the level of particle physics but emerges at the macroscopic level. 3 Evert Stolte Evert Stolte 1 year ago As a physics (master) student in Leiden, I'm so sad I missed your Ehrenfest Colloquium in 2018. At the time, as a bachelor student, I only seldomly attended these because most of those lectures went far over my head. I've just watched the recording online, and I can conclude the same would have probably happened with your lecture. So in the end I'm kind of glad I have listened to it only now as a master student, after a QFT course and a whole lot more physics experience overall. It was definitely a great introduction to emergent gravity from quantum field theory, and I now also have a greater appreciation for Everett's 'Many World' interpretation. (If anyone else is curious, you can watch it here https://www.universiteitleiden.nl/en/news/2018/09/livestream-sean-carroll-gives-ehrenfest-colloquium by clicking on the livestream link at the bottom) I've really enjoyed your last few lectures of 'The Biggest Ideas'. Especially the one about Entropy gave me new insights and a more formal firmer grasp of the concept. In the past, I've mostly viewed Entropy as the Boltzmann entropy, with other versions as 'things that are the same, but different in interpretation'. Although I knew this to not really be true, I've never really looked into it and therefore never understood the other forms of entropy (nor, as it turned out, the importance as the concept as a whole.) I hope it can help me communicate the topic in a better way to students in the upcoming semester as a student teaching assistant for the 2nd year bachelor Statistical Mechanics course. 6 Martin DS Martin DS 1 year ago Great video!! Thanks Sean 😁 1 Heroin Buttsex and Lord of the Rings Channel Heroin Buttsex and Lord of the Rings Channel 1 year ago Sean, isn't there an upper limit to how much momentum any particle can have? Is this a curious area? Paul E. Bailey Paul E. Bailey 1 month ago I thought Emergence was essentially a phenomenalogical proposition. 'As above, so below' Co or mutually generative. So, the big question is: what emerges? A better model or concept for reality. Phil Gallagher Phil Gallagher 1 year ago I love the fact that, because of a worldwide disaster (Pandemic), we all get the opportunity to hear lectures from Nobel Laureates and people who are really at the cutting edge of their particular disciplines. There was previously no chance that AT THE SAME TIME, people like Sean, Brian Greene, Roger Penrose etc would be able to produce videos about their respective fields while the general public ALL have the time to take it in (whether we understand it or not is a different matter!!) So now, we have the "Perfect Storm". The experts have the time, the public have the time AND the technology is sufficiently advanced and available to allow this to happen. Thanks to the Coronavirus, those of us well enough can gain a whole lot of information. (Imagine if this had been the case in Einstein's time or even Newton's time!) 1 Michael J Morrison Michael J Morrison 1 year ago Question: If theoretically there are a semi- infinite number of 'spectacle-like' theories through which 'reality' can be faithfully observed BUT each have individual limitations, will it ever be possible to see the total of reality except by somehow discovering and then combining all such theories? Would this not be a semi- infinite or infinite venture? Or are we nearly there yet? Thank you for your amazing work. sudip patra sudip patra 1 year ago great, can there be a theory which suggests why 'real patterns' may exist? under which conditions ? Tony D'Arcy Tony D'Arcy 1 year ago Given the correct combination of atoms and molecules plus the right energy conditions in normal space, a pizza could strongly emerge from an oven ? Whether it is allowed pineapple or not remains a deep mystery. 1 ridespirals ridespirals 1 year ago I'm sure this video is great but the gases/gasses thing just blew my mind. makes perfect sense now that I know but I don't think I had ever thought about or encountered that before. Pamela Collins Pamela Collins 1 year ago Question: Are our bodies composed of fields and wave functions on the most basic level? Pavlos Papageorgiou Pavlos Papageorgiou 1 year ago 36:35 I'm not sure if emergent macroscopic behaviour is the phenomenon, or a certain reduction of extant configurations is the phenomenon. You can abstract the Earth as a point mass because mass tends to clump not in every possible way but in spherical bodies. Decoherence is another vast reduction or configurations that can be seen. So emergence as well as Dennett's patterns may be clues to that vastly compressed reality where only a tiny subset of the mathematically possible configurations actually exist in some sense. In a sense the job of physics is to map that reduction at every scale. Worsel Strauss Worsel Strauss 1 year ago Would thermodynamics count as an emergent theory, and if so wouldn't it be an example of strong emergence? Erin Morton Erin Morton 1 year ago So the mumuration behind you would be many to one (course grained) ie lots of birds into one mummur. And I guess in that case heterostructural because the mummur has emerged from the starlings? I love your talks Sean. They help me sleep as well as fascinate me when I am awake. I love the pace and the tap tap tapping of the pen. On so many levels - thank you. Also, as someone who has been run over by a non-dual realisation, I find your talks very meditative. cheers mate. (: 1 Therese Voerman Therese Voerman 1 year ago Interesting video. I think you'd benefit from looking into the late Roy Bhaskar's work in the philosophy of science. Wafikiri Wafikiri 1 year ago I am developing an emergent, mostly mathematical theory of cognition that is applicable to seemingly different portions of reality: nervous systems (of course), microbial life, genetics and epigenetics in the tree of life, immune systems... About consciousness and qualia, maybe they are emergent properties of cognition. I still don't know and have to think a lot more unless I get the kind of insight I had about cognition. Traruh Synred Traruh Synred 1 year ago Seems to me that central limits theorem is a origin of lot of emergence. If, e.g., the force between particles (and walls) was 1/d rather than faster fall off (2d case?) then pressure would not emerge as from averaging over a lot of collisions. Does that sound right? Stefan Batory Stefan Batory 1 year ago You can take approach to it as if classical definition was superior to quantum almost as classical cluster was a sum of all orders of magnitude. Then the clasical potencial describes reality that only matters and you treat wave even without intercepting the classical limit as a sort of partial integral of everything happening under the classical curve. I am sure you know how complex one must be to comprehend so much data at once. The classical limit is where we are rather we like it or not. The point is to eliminate all ignorance related to entropy but still be able to derive consequences of all this knowledge to fit to the classical potential slope and support it. Easy to say probably. With every next part of this series I see more clearly the awesomeness of the whole concept and I deeply appreciate it. Sadly it looks like we are very close to applying infinitesimal to this series. Therefore one must admit that much entropy was consumed over this grat treat marking the genius of its creator. Many thanks for that time. D C D C 1 year ago “Two possibilities exist: either we are alone in the Universe or we are not. Both are equally terrifying.” - Arthur C. Clarke I feel the same sentiment towards Strong Emergence - which happens in reality or does not. Either way, it boggles my mind. To believe, understand, and possibly know that each of us is only a smattering of nougat within a colossal wave function and derivable from a quantized, basement-level particle physics seems irreconcilable with our subjective conscious experience. But what is the alternative? Invoke some goofy analog of the luminiferous aether?!? Science peters out around the edges (presumably because we're not done yet), but its core principle of reductionism is not soft around the edges - it's as crisp and well-defined as the monolith that mesmerized our ancestors in Clarke's 2001: A Space Odyssey. I'm particularly taken by the example of the 3+1 dimension Conformal Field Theory (CFT) being the boundary condition of a 4+1 dimension Anti-de Sitter (AdS) space. Makes me wonder if there's a philosophical analogy to be had - like abstract objects being a lower-dimensional boundary condition of the concrete. For example, many philosophers believe that number is the essence of quantity - that numbers are mind-independent objects and that a description of reality would be incomplete without their inclusion. Perhaps this so-called essence is profitably thought of as a lower-dimensional boundary condition. But so far, going from AdS to CFT seems more straight-forward than the other direction. It feels far easier to agree that gravity in AdS doesn't imply any contradiction within CFT, but I don't quite see how gravity is to be inferred from CFT - and it must be inferred if the emergence is to be weak, right? (It feels even stranger to suggest that an abstract object infers a concrete object. What's next - inferring an ought from an is?!?) Finally, is there any limit to the chain (or web) of inference? Is the 4+1 AdS just a boundary condition for a 5+1 Something Else, with another spectacular reality like gravity popping out from it? It's like turtles all the way up - like we could synthetically generate a never-ending progression of knowledge. Anyhow, I think it was essential for Dr. Carroll to broach the topic of Strong Emergence and I'm so glad he did. As a scientist, he's properly committed to naturalism and reductionism but also properly open to investigate a purported counterexample. He's making both science and philosophy better in the process. Shalkka Shalkka 1 year ago This clock has no moving hands. It is still a true clock describing real time, it is just that its domain of applicability is only noon. If you can make a correspondence between a particular sand heap and a mathematical theory of physics does that mean that the sandheap is a a theory of physics. How much of emergence is property of clever mappings between otherwise unconnected abstractions. Is reduction in the eye of the beholder? 1 Jonathan Sharir-Smith Jonathan Sharir-Smith 1 year ago Hi Professor Carroll - I'm not sure if you'll see this seeing as it's an "old video", but I figured I would ask. Would you be able to add reference textbooks (your favourite, or "the best", books on the subject) to your descriptions at some point? These videos will be invaluable resources for people interested in these topics for a long time, and a comment (from you especially) indicating where people could go for more info, whether more formal or otherwise, would be incredibly useful. Incidentally, it would also be a way to plug some of your books (thinking Spacetime and Geometry for your videos on GR). Thanks again for these amazing videos! Om3ga Om3ga 1 year ago Prof. Sean Carroll please make the next episode of 'Biggest Ideas in the Universe' on String Theory and M - Theory 1 Freq-NC8 Freq-NC8 1 year ago Although I'm sure this isn't an original thought—I've become more and more convinced over time that quantum gravity hides in the one place we have yet to probe with any real acuity; virtual particles in the vacuum. Indeed, gravity may be the emergent behavior of the vacuum energy—the resonant wavelength of virtual particle pairs imparting a fluid-like momentum along the surface of aggregated matter at the macro scale. Akin to a Zel'dovich cylinder. Although the end result is not superradiance, but momentum via resonant virtual particle wavelengths and the surface of a body or system. Paul Perkins Paul Perkins 1 year ago The last few diagrams put me in mind of something that is maybe not the same as Strong Emergence, but looks a lot like it, and (IMO) does happen: your micro theory is incomplete, its domain is not all of reality, and you have a macro theory that works for some parts of reality where your micro theory doesn't. Then the macro theory might make accurate predictions that the micro theory can't, but only because you are in a situation where you can't, or shouldn't, use the micro theory anyway. Erb Terb Erb Terb 1 year ago How do we know planets are not moving at the speed of light, relative something? Planets are for instance moving at the speed of light, compared to a light ray. We just say the light ray is really fast while we are stuck in the beat frequency of matter. I might be sophistify to much, but it just looks awkward in my mind, and my emergent mind is all I got Krishna Phanindra Krishna Phanindra 11 months ago Simply beautiful...Can't be any better!! nibblrrr nibblrrr 1 year ago 43:16 Fun fact: The name "Ehrenfest" sounds like a completely plausible German compound noun, meaning "festival in honor (of someone/thing)" - but this word does not exist. (I presume the name comes from the adjective "ehrenfest", meaning "honorable" - "fest" translates to "firm, sturdy" here instead of "festival", cf. "steadfast". But it's archaic and therefore not widely known even among native German speakers.) ShamanicKnight ShamanicKnight 1 year ago Some people use the term 'reality' for that which is realised, i.e. within a 'mind' - and 'actuality' is what is actually 'out there' (outside of a mind) irrespective of the various perceived 'realities' of conscious beings. 1 David Hand David Hand 1 year ago Isn't the measurement effect pretty much strong emergence? More accurately the Born Rule, which is not covered by the Lagrangian, that in principle applies to particles in mass via probability? David Hand David Hand 1 year ago I'm always wondering how QFT approximates (in the limit) F = ma, F = kq1q2/r2, etc. Does it actually work out, or are we thwarted by infinities in the calculation? Also, how can you even have r2 when the positions are uncertain? And is it possible to derive V(x,t) from a wavefunction in a coupled field? E.g. I know psi of electron, can I then calculate V(x,t) for the photon field, or vice versa? affablegiraffable affablegiraffable 1 year ago 27:14 that diagram is very category theory. I wonder if it would make sense to take a categorical limit and find the "least" theory that ecapsulates special relativity and Newtonian mechanics. Ron Tira Ron Tira 1 year ago Dear Sean You talk elsewhere about spacetime being emergent and quantum mechanics being fundamental. I wonder the following: 1. The wave function is characterized by its length and amplitude, but don't they both require space as a precondition? What is wavelength and amplitude without space? 2. Boson and fermions are differentiated by their ability (or lack of) to occupy the same… space. Doesn't that mean that space is a precondition for their emergence? 3. Unless quantum mechanics describe a static unchanging state, if there is any interaction in the quantum world, doesn't that require time as a precondition? Doesn't any quantum dynamics require time as a precondition for their emergence? 4. If the quantum field is a harmonic oscillator, and all phenomena are merely disturbances to the harmonic oscillator, then: (a) don't you need a more fundamental cause of those disturbances? (b) where is the energy required for disturbing the harmonic oscillator coming from? Don't you need a more fundamental source of energy for the quantum field to be disturbed? All the best dizy dizy 1 year ago Okay prof. You're too dang fast... and i love every second of it ... im okay thinking "this week im going to get this one in" boom another one and im like "shit! Im dumb, im dumb, im dumb... hurry up this is basic shit get on board its one hour" ... lol this series has taught me more with out being to over my head than anything else ive ever come across... honestly thank you for taking the time out of your day to make these... it means alot to ppl like me who were never brought up with science and never pushed to see how amazing it is ... so many times in the middle of it i realize i need to learn advanced things but i have my own life and so many times i feel i get the gists so thats good enough?!?... then here you come bridging the gap... it may be nothing to those who know but to me its a perfect balance ... idk if you will read this but you have taught me so much, just wanted to say thank you 🤷‍♂️... youre a good dude 1 Cristiano Pruneri Cristiano Pruneri 1 year ago "We need about ten billion dollars for a new collider to test the frontiers of elementary physics". "You ask billions for Elementary Physics? Sod off!" Thus was doomed Sean's attempt to re-christen "Fundamental Physics" Pavlos Papageorgiou Pavlos Papageorgiou 1 year ago 1:31:35 strong emergence is compatible with a fully known micro-theory if the emergent phenomenon is completely outside of the micro ontology. Consciousness could be an example. It could be a brute fact that if you make a certain pattern out of particles, the pattern has a subjective experience. And you could perfectly well describe in the micro theory what kinds of patterns do this, but there's nothing in the micro theory to measure that subjective experience. It's not that there's any fuzziness or spookiness limiting the micro theory, just the Venn diagrams you're drawing could be disjoint. There's probably no great insight in this, other than to stop seeing it as a contradiction. R C R C 1 year ago I know the video is about weak emergence. But I am curious how Professor Carroll arrives at being a compatible-ist for free will, while being totally against strong emergence. I’m going to listen to his Mindscape Podcast with Dan Dennett again... AnarchoAmericium AnarchoAmericium 1 year ago (edited) Prof Carroll, you keep emphasizing structure, mapping in your videos. Are you secretly a physicist that uses category theoretical thinking in the background? dePlant dePlant 1 year ago I hope Sean has lots of children and grandchildren. I’d like to think my kids will grow up in a world with more Carrolls in it. Yes i know intelligence is only partly heritable but imagine growing up with Sean as a dad. AnswersInAtheism AnswersInAtheism 1 year ago @Sean Carroll Love your stuff. What program are you using on the iPad to do the chalkboard. I need that for my channel. Also ever heard of Linea Sketch? Boris Petrov Boris Petrov 1 year ago (edited) I like an illustration of "emergent properties": -- One can study individual atoms of oxygen and hydrogen for eternity -- try to figure out all the incredible properties of their combination -- water.... These properties are "emergent" because we don't know enough... PS: What if entropy has no upper limit? In that case at Big Bang entropy could have perhaps "easily" been the lowest... PS2: Let's guess what will be the next lecture topic? PS3: Quantum computing at room temperature might be another interesting topic? See Matthew Fisher and nucleus spin -- https://www.news.ucsb.edu/2018/018840/are-we-quantum-computers Martin Johnsrud Martin Johnsrud 1 year ago I find the way of talking about limits as "hbar goes to zero" or "G goes to zero" to be misleading. If that was necessary for the limits to exist, they would not be noticeable in the real world, as the constants are in fact constant. I find combining the constants with parameters of the problem and saying "as hbar becomes negible compared to this" much more enlightening. Fer Shred Fer Shred 1 year ago Are you going to talk about fractals and the feigenbaum constant in one of these videos? 5 Barefoot Barefoot 1 year ago At 1:00:05 you talk about Hyperion not spreading into a blob of probability due to decoherence. I'm with you there. Then you go on to say specifically that it's being bombarded with photons all the time that are constantly observing it / branching the wave function of the universe. What about its own internal interactions? Thermal motion of its internal atoms, for example, or the constant electromagnetic forces caused by its various chemical bonds? This is something I've never quite gotten hold of with my mind... I've seen you answer this question several times, at the Royal Institution for one, and in a couple of other lectures Q&A sections, and what you said, to paraphrase, is roughly, "Not all interactions cause branching of the wave function, but there isn't time to specify which ones do and don't and why." Well... the upcoming Q&A video would seem to be the perfect opportunity! :D Did you just omit Hyperion's own internal observations of itself? Or do those interactions (or at least some of them) genuinely not cause splitting/collapse because of reasons? (Entanglement, maybe?) In either case, when exactly does an interaction branch the wave function of the universe, and when doesn't it? Or is it simply not well-defined due to something like quantum relativity? I seem to recall a passage in Something Deeply Hidden that mentioned that... but I think it was in the roleplayed conversation between father and daughter and less than perfectly clear. Still, something about what branches the wave function depending on frame of reference, maybe? James Edward James Edward 9 months ago Dude is the finest science communicator out there, period. This Biggest Ideas series is absolutely phenomenal. He's in the absolute sweet spot of communicating these concept at just the right level of detail and sophistication for people who are huge fans of the natural sciences, but don't have the math/science backround to read and comprehend actual papers on this stuff. My top three: Sean Carroll, Sabine Hossenfelder, Jim Al-Khalili. I see anything by them I'm dialed in. Kjv35 Kjv35 1 year ago Hi Professor Carroll and the rest of the physics community here on YouTube. At around 34:30 - 35:00, you mention that we can describe the motion of a large object in the coarse-grained viewpoint by strictly analyzing the center of mass and that "none of [the] relative positions and velocities matter at all." My question is: if the Center of Mass M and its velocity v_{COM} are "emergent properties" of the system, then what about the angular momentum of the entire body, L? I believe that we need to consider the motion of the constituent masses relative to the COM to calculate the angular momentum of the entire body. Do we consider the angular momentum of the large body an "emergent property" of the system? Or was this example specifically to illustrate that the linear dynamics of the system are emergent just from knowing M and v_{COM}? Curious to hear your feedback, thanks! dePlant dePlant 1 year ago Is this true? One can apply reductionism eg climate-weather-statistical gas- molecules-atoms but once you get to the quantum level there is no way even in principle NOT to use a statistical ontology? In other words... is it 🐢 ‘s all the way down until you get to a 🦆? 31041955 31041955 1 year ago after all these lectures , my conclusions are..... consciousness is probably fundamental and it creates the world we experience every day........ 1959Berre 1959Berre 1 year ago I can describe gasoline on a the microscopic level. Does this imply I can I expect a macroscopic theory of a combustion engine to "emerge"? rv706 rv706 1 year ago (edited) I have a question: what would count as empirical proof of strong emergence? ---- That many microstates give rise to the same macrostate is nothing new and certainly doesn't imply emergence; also, in the absence of an explicit derivation of the macroscopic law from the microscopic one, one could always say that we don't know how to perform that derivation *yet*, and not that such a derivation is impossible in principle. I think an empirical proof of (strong) emergence would be: showing a system for which the microstate doesn't determine the macrostate (which is a weird thing). Otherwise, if the microstate determines the macrostate, I'm persuaded that it follows that the microscopic law determines the macroscopic one (assuming the microstate is always well defined). 1 Jon Adams Jon Adams 4 weeks ago Certainly the different domains need to match at their mutual boundaries. H 1 H 1 1 year ago I am sorry, but the concept of emergence seems to me to be used in a very hand-wavy manner here and by most people. I don't think it has as much explanatory power as is commonly assumed. Corbin Simpson Corbin Simpson 1 year ago Two things. First, as somebody who doesn't believe in reality, I usually phrase it by saying that "reality is hypothetical"; this can be formalized. Second, starting at 26:30 or so, you're drawing commutative diagrams in some category! I approve but wish that you'd have said something. John Długosz John Długosz 1 year ago How many particles make up Earth? Well, the mass is 5.97237e24 kg, so that means about 6e27 moles of nucleons. Interestingly a mole is about 6e23, so the Earth's mass is (10 mole) kilograms, which means it is now easy to remember. Multiplying, ==> 3.6e51. That's imprecise enough that it may or may not count the electrons too, so call it 4e51 counting protons, neutrons, and electrons. I don't know how to figure the number of photons, caused by the temperature of the material, but maybe you don't count that anymore than you count the gluons. You could also count the neutrinos that are passing through at the moment, or the number that exist momentarily due to radioactive elements. I think a much harder problem is to determine how many meaningful ways there are to count the particles! tripiecz tripiecz 1 year ago I hope I'll understand all these amazing things by the time I'm 500. 1 Theodor Samoladas Theodor Samoladas 1 year ago From here on, it seems that theories are giving way to 'theorism' methodology after all... aresmars2003 aresmars2003 1 year ago It seems sometimes say "multiple theories" and sometimes "multiple models". I'm not sure the difference. I suppose a theory gives "laws" of predicting future behavior. When I hear emergence, I think of consciousness, and E.F. Schumacher said we need to recognize 4 levels of being to help distinguish what a model can predict. https://en.wikipedia.org/wiki/A_Guide_for_the_Perplexed#Levels_of_being For Schumacher one of science's major mistakes has been rejecting the traditional philosophical and religious view that the universe is a hierarchy of being. Schumacher makes a restatement of the traditional chain of being. He agrees with the view that there are four kingdoms: Mineral, Plant, Animal, Human. He argues that there are critical differences of kind between each level of being. Between mineral and plant is the phenomenon of life. ... Schumacher realizes that the terms—life, consciousness and self-consciousness—are subject to misinterpretation so he suggests that the differences can best be expressed as an equation which can be written thus: "Mineral" = m "Plant" = m + x "Animal" = m + x + y "Human" = m + x + y + z In his theory, these three factors (x, y and z) represent ontological discontinuities. He argues that the differences can be likened to differences in dimension; and from one perspective it could be argued that only humans have 'real' existence insofar as they possess the three dimensions of life, consciousness and self-consciousness. Schumacher uses this perspective to contrast with the materialistic scientism view, which argues that what is 'real' is inanimate matter, denying the realness of life, consciousness and self-consciousness, despite the fact each individual can verify those phenomena from their own experience. He directs our attention to the fact that science has generally avoided seriously discussing these discontinuities, because they present such difficulties for strictly materialistic science, and they largely remain mysteries. ... Schumacher points out that there are a number of progressions that take place between the levels. The most striking he believes is the movement from passivity to activity, there is a change in the origination of movement between each level: Cause (Mineral kingdom) Stimulus (Plant kingdom) Motive (Animal kingdom) Will (Humanity) One consequence of this progression is that each level of being becomes increasingly unpredictable, and it is in this sense that humans can be said to have free will. He notes increasing integration is a consequence of levels of being. A mineral can be subdivided and it remains of the same composition. Plants are more integrated; but sometimes parts of a plant can survive independently of the original plant. Animals are physically integrated; and so an appendage of an animal does not make another animal. However, while animals are highly integrated physically, they are not integrated in their consciousness. Humans, meanwhile, are not only physically integrated but have an integrated consciousness; however they are poorly integrated in terms of self-consciousness. Another interesting progression, for him, is the change in the richness of the world at each level of being. A mineral has no world as such. A plant has some limited awareness of its immediate conditions. An animal, however, has a far more rich and complex world. Finally, humans have the most rich and complicated world of all. ... Schumacher argues that the ideal science would have a proper hierarchy of knowledge from pure knowledge for understanding at the top of the hierarchy to knowledge for manipulation at the bottom. At the level of knowledge for manipulation, the aims of prediction and control are appropriate. But as we deal with higher levels they become increasingly absurd. As he says "Human beings are highly predictable as physico-chemical systems, less predictable as living bodies, much less so as conscious beings and hardly at all as self aware persons."[6] The result of materialistic scientism is that humanity has become rich in means and poor in ends. Lacking a sense of higher values Western societies are left with pluralism, moral relativism and utilitarianism, and for Schumacher the inevitable result is chaos. Andrew Szymczak Andrew Szymczak 1 year ago (edited) For every choice of macro evolution operator and coarse graining function, won't there always exist a (possibly empty) subset of reality where the diagram commutes? In this sense it seems that "strong emergence" is ill-defined. One way to make it well-defined is to use the set-picture that you subsequently drew, where "strong" means that there exists a subset W of reality where the macro theory applies but not the micro theory. Then "weak" is just the special case of "strong" where W = ∅. So the naming "weak" and "strong" seems to be really quite unfortunate. Weak emergence not only has a stronger hypothesis but also aligns more strongly with our conceptual view of the word "emergence". Using this definition, it seems plausible (though perhaps unlikely) that our quantum and classical theories could be "strongly" emergent, where there are certain situations where QFT is wrong yet CFT happens to be right, given that QFT is probably not the theory of everything. RedPandaTronics RedPandaTronics 1 year ago You are right, plural of gas is gases (one s), but in British english it is spelled garses :) ironic legacy ironic legacy 1 year ago (edited) Is ehrenfest’s theorem why in a bubble chamber, a particle leaves a trail that appears to be a particle on a trajectory? NVM, right after that you answered it 1 Cyan Cat Cyan Cat 1 year ago I like his audio-only podcasts because there's none of that blackboard writing things down business. Don Wortzman Don Wortzman 1 year ago If Earth's orbit around the sun is in some sense a straight line, why when I draw a straight line on paper does it look straight. What am I missing M S M S 1 year ago (edited) This is somewhat scary. So the Pauli principle is rather a dichotomy than a statement about fermions. What would the macro world look like from a micro/QM perspective? As opposed to the traditional other way around. No words on the law of great numbers? Why isn't this taught in undergrad school? Regards, Marcus of Sweden Calvin Grondahl Calvin Grondahl 11 months ago Reality is what we can agree on and since humans don’t agree on much then there isn’t a lot of reality. Apollyon 1975 Apollyon 1975 1 year ago Space and time are probably not fundamental, even though science has hung their hat on it being fundamental. Sergey Novikov Sergey Novikov 1 year ago (edited) if the weak emergence is true then we can have a physics theory of life which will be capable in fundamental terms of physics precisely describe the Darwinian evolution and different living structures (whereas consciousness is just a natural feature of complex high level living organisms).. i'm sure we can and very close to find such a physics theory.) and this in its turn will radically change our understanding of the universe and of ourselves as inseparable part of the physical universe. 1 Zei33 Zei33 1 year ago Interesting ideas. Good video dannyboi404 dannyboi404 1 year ago isn't everything we know something of an emergent theory? almost seems cocky to assume the "fundamental" equations of reality are findable/knowable. similar to believing there's a point where science ends. Matthijs Hebly Matthijs Hebly 1 year ago Amazing, fantastic Matts Toaster Matts Toaster 1 year ago (edited) " Gases is written with one 's' and not two; I've written this word a thousands times " Welp. I felt that, because I've been spelling it gasses for my entire life....fml Andrew Ferg Andrew Ferg 1 year ago The material is an emergent property of the platonic, not the other way around. An adolescent cultural bias should not prevent a brilliant mind from seeing this. “It is clear that these physical-only processes somehow on the one hand give us the right answers, but on the other hand that they are controlled by another world of ideas somehow; they’re coming from somewhere else.” (Nima Arkani-Hamed--- theoretical physicist, permanent faculty at the Institute for Advanced Study at Princeton, and director of The Center for Future High Energy Physics (CFHEP). Rick Harold Rick Harold 1 year ago Awesome. Love the video! Thx Nicholas Nicholas 1 year ago I'm thinking that one of the biggest ideas in the universe is putting the biggest ideas in the universe into a series of YouTube videos. 1 Geoffrey Payne Geoffrey Payne 1 year ago How did you know I'm living 1000 years from now?! Samir Petrocelli Samir Petrocelli 11 months ago Just like music can't be reduced to physics, nor the psyche can't be reduced to neural impulses. sschupack sschupack 1 year ago What is the relation between your being a compatibilist (no conflict between determinism and free will) but not believing in strong emergence? rv706 rv706 1 year ago 24:11 - Category Theory sneaking in, at least heuristically 6 Descartesdom77 Descartesdom77 1 year ago Not going to lie, Strong Emergence always sounds like Superstition to me. 3 Ben Schreyer Ben Schreyer 1 year ago Earth mass is 10^25 kg, Si 28g/mol, 10^25*1000/28*10^23= about 10^50 #science #physics #ideas The Biggest Ideas in the Universe | Q&A 21 - Emergence 34,354 viewsAug 16, 2020 749 DISLIKE SHARE DOWNLOAD CLIP SAVE Sean Carroll 154K subscribers The Biggest Ideas in the Universe is a series of videos where I talk informally about some of the fundamental concepts that help us understand our natural world. Exceedingly casual, not overly polished, and meant for absolutely everybody. This is the Q&A video for Idea #21, "Emergence." I took the opportunity to just give a mini explanation on the work I and others have recently been doing on understanding the emergence of spacetime. Here are some relevant research papers: Mad-Dog Everettianism: https://arxiv.org/abs/1801.08132 Locality from the Spectrum: https://arxiv.org/abs/1702.06142 Finite-Dimensional Hilbert Space: https://arxiv.org/abs/1704.00066 The Einstein Equation of State: https://arxiv.org/abs/gr-qc/9504004 Space from Hilbert Space: https://arxiv.org/abs/1606.08444 Einstein's Equation from Entanglement: https://arxiv.org/abs/1712.02803 Quantum Mereology: https://arxiv.org/abs/2005.12938 My web page: http://www.preposterousuniverse.com/ My YouTube channel: https://www.youtube.com/c/seancarroll Mindscape podcast: http://www.preposterousuniverse.com/p... The Biggest Ideas playlist: https://www.youtube.com/playlist?list... Blog posts for the series: http://www.preposterousuniverse.com/b... Background image: Auklet flock, Shumagins 1986, by D. Dibenski, https://commons.wikimedia.org/wiki/Fi... #science #physics #ideas #universe #learning #cosmology #philosophy #emergence 97 Comments rongmaw lin Add a comment... Sean Carroll Pinned by Sean Carroll Sean Carroll 1 year ago Erratum: I bungled the bit about Henrietta Leavitt and parallax. She actually used Cepheids in the Large and Small Magellanic Clouds, which she (correctly) assumed could be treated as being located at approximately the same distance. 4 krzysztof mekwinski krzysztof mekwinski 1 year ago (edited) If I saw this video six months, I wouldn’t understand it at all. Thanks to 4 months of watching “big ideas” I could understand it! Amazing! I am a bit proud of myself . But it is not me, it is Sean beeing such an amazing teacher ! Thank You! 17 Giordano Gaudio Giordano Gaudio 1 year ago Hi Sean! I'm an 3rd year undergrad in physics and mathematics up here in Canada and I'd like to poke a little farther into Mad Dog Everettianism. So basically, it seems like regardless of if you start with fundamental time or not you always have the elements of the hilbert space being dependent on some scalar quantity (functionaly) in such a way as to have derivatives. So correct me if I'm wrong but you are always implicitly assuming somethings about the original hilbert space. Namely that it is some subset of functions from the real numbers to some C1 manifold. Moreover since these are functions it seems natural that you also assume they are at least L1 (L2 is usually assumed for quantum mech). The reason I bring this up is because it makes Mad Dog Everetianism seem like a bit of a misnomer. E.g. your not saying all that exists is a Hilbert Space and a Hamiltonian, instead your saying all that exists is a specific Hilbert Space of C1 and L2 functions. Is this an escapade assumption or are we necessarily confined to functional hilbert spaces? Thanks again for this fantastic series and not shying away from the mathematics. It's always a pleasure to watch them. 5 Stepan Anokhin Stepan Anokhin 1 year ago Sean, THANK YOU SO MUCH! The most thought-provoking series on youtube I've ever seen. 17 VECTOR 1 CLASSIFIED VECTOR 1 CLASSIFIED 1 year ago Finally...finally I've found an almost endless amazing listening series after series, awesome stuff Sean, been looking a very long time for a site like yours, very, very apprietted sir' 1 Rhonda Goodloe Rhonda Goodloe 1 year ago Sean, Thank you again for this series. Going to really miss it when it is over. 7 Tan Vachiramon Tan Vachiramon 1 year ago Thank you for continuing to post these videos. They are so packed with amazing concepts and insights! Joseph Cughan Joseph Cughan 1 year ago Sean, when you’re done with this series, please do another one. I don’t care which topic or ideas you cover, I just need more. I don’t want this to end. Alex Madeira Alex Madeira 1 year ago Fascinating - This is the most interesting episode so far in what I think is the best series on the internet. Sean is a wonderful Nestor! Paul C. Paul C. 1 year ago This arrived a bit too late on Sunday evening here in Wales, so watching on Mon morning instead. And of course, many, many thanks again Professor Carroll, for this truly wonderful series. Please don't stop. Keep them coming. Thank you. Jeremy Payne Jeremy Payne 1 year ago I listen to you a lot. You broke new ground here for me with respect to the relationship between eigen states and symmetry and duality. Mind blown 🤯 Shytam Shytam 1 year ago Another great lecture and Q&A followup. I'm learning so much! Also, nice strong finish to this one. :) Pavlos Papageorgiou Pavlos Papageorgiou 1 year ago 1:06:00 You're working on the most interesting question in all of physics, which I think is this: Not what our world is actually like, but of all possible worlds in the most general sense, what properties are the ones that yield a world with evolved beings like ourselves. 1 Jason Joslyn Jason Joslyn 11 months ago Hello Sean, I love this series! I have a question about "Strong Emergence". What if instead of there being a subset of a circle where the Macro has its own rules that are not a part of the Micro, we were to say that those Macro rules that aren't "just the micro" are irrelevant to the micro. Not violating them but also not impacting them in any significant way? For example, in radio everything that happens is completely specified by the micro rules. Except the informational content of the audio signal produced. It doesn't violate or go beyond any rules of electromagnetism or electricity for the signal to speaker action to playback talk radio vs classical music. But as a Shannon information system, the forms that come across the signal may be more or less surprising. So the formal or Informational content could be a "macro" property with its own meaningful rules that are not completely specified in the micro systems. But they also don't violate them. They are essentially irrelevant to the microstate and don't change the microstates complete description of that part of the total system. This might relate to David Bohm's idea of "Active Information". Do you think that this scenario is a valid example of "Strong Emergence"? Chirality452 Chirality452 1 year ago I think you addressed my question (or Sergey Novikov's) and big surprise it is your current area of research. I think you may well be on to something very significant. I need to watch this again! Bui if gravity is the geometry of space-time and that geometry is an emergent phenomena of quantum mechanics that would avoid the renormalization problem of quantum gravity. Boris Petrov Boris Petrov 1 year ago (edited) Thank you for great lectures !! A comment on the courageous genius-mathematician Roger Penrose, if I may: Roger wrote / published his book on conscience and quantum mechanics (QM) in 1994. He developed his hypothesis and detailed mathematical arguments for QM's role -- the intriguing idea about microtubules came late in the process via anesthesiologist Stuart Hameroff and he used it as "placeholder" there. In all later interviews and books he maintained his analysis and proposition for QM role but expressed increased skepticism about microtubules (which, on the other hand, are indeed astonishingly impressive in their own right). So -- a correct description for Roger Penrose's position is that he maintains that QM must play a major role in "conscience" via a mechanism not understood yet (microtubules or not). I believe Penrose will ultimately be proven right -- as usual. I am still struggling with his 2004 seminal book "The Road to Reality" in which he more explicitly clarifies his position on the above and other physics and cosmology subjects. (Characteristically for Penrose -- in it, once again, he opposes in detail the current universally adopted orthodoxy about Alan Guth's cosmic inflation in first trillionth of a second after Big Bang -- which he considers mathematically as nonsensical to achieve such inflation objectives)..... Best regards -- with immense gratitude for your efforts Nadrieril Feneanar Nadrieril Feneanar 1 year ago Thanks for another amazing video! There are two things you said about time that felt weird to me: The first is that the way you describe how time could emerge looks super naive compared to how you spoke about space. It is as if you had said "for space to emerge, we assume that there is a subsystem that tells you where you are in space". Clearly the story is way more subtle for space, why would it not be so for time? If time and space are expected to be on an equal footing, I'd expect that they emerge together from the geometry of entanglement entropy like you described. I'm super curious to know why you favored the more 'naive' approach there. The second thing that surprised me is that you said the timeless Schrodinger equation should be H psi = 0. This is equivalent to saying that psi is an eigenvector for the eigenvalue 0. That's a strong assumption on the Hamiltonian, right? Why not have psi just be the ground state (or any other eigenvector)? It would still not be evolving with time (modulo global phase), but now all the mereology should still work and no extra assumptions on the Hamiltonian would be needed. Is there a deeper reason for choosing 0 there? 1 Pillio Zoltan Pillio Zoltan 1 year ago (edited) If a wormhole exists, what is the volume of that space which includes one end of the wormhole? And what is the maximum entropy in that volume? Is it a maximum based on it's surface, when there is a potentially infinite universe at the other side? :D R C R C 1 year ago Really enjoyed this glimpse into cutting edge theoretical research. It’s like a tasty treat as reward for following along with all the previous videos in the series. James Stewart James Stewart 1 year ago Surely I'm not the only one finding this walkthrough more intuitive than the emergence video Michael Wrenn Michael Wrenn 1 year ago Thanks to your generosity and courage to parse physics in a public forum, I have the privilege to witness someone with ample know-how, scrub Hilbert space with a Hamiltonian to explore for emergent properties of time. Using my own, far less competent knowledge and command of quantum properties, I see no hint that time and gravity do or can have quantum substrates. I am compelled by notions of time and gravity that renders them both inherently and purely continuous. I think they cannot be truly represented on a number-line unless the numbers are smeared together and useless. Long before quantum mechanics was discovered, great mathematicians performed wonders with numbers. I was intrigued and aided in my understanding of calculus by the delta/epsilon view of approximations. Numbers are inherently quanta. Isn't it possible that a line in its purest form is not an expression of quanta, but is indivisible, as time and gravity appear to be? Our clocks divide time into useful quanta. At this time, I am hard on the trail, too, hunting for something deeply hidden. My trail is only quantized by the steps I impose upon it. 1 Traruh Synred Traruh Synred 1 year ago This discussion of emergence of space and possible time reminds me of the Heisenberg picture of QM in which the time dependence is put in the operators and wave-function is static/fixed. Schrodinger picture seems more intuitive and so that pretty much what is taught, but many Hesenber picture might lead to a different way of thinking about them. How would one talk about Everett interpretation in Heisenberg's way? Would operators 'split'? 1 Epiphyte Epiphyte 1 year ago Any chance you could explore the connection between economics, astronomy and physics? Isn't there a connection? Economics is all about how things are ordered, which is a function of interactions/influence. Naturally it is instinctual to want to improve the order of things... Pavlos Papageorgiou Pavlos Papageorgiou 1 year ago (edited) 1:08:47 Time is a measure of distance in some abstract space. It doesn't flow, it's just a metric. We flow, or rather we're an extended structure in this abstract space and our structure feels the flow of time because of certain relations like there's more hydrogen periods in a heartbeat or more paths to the future than the past. Howard Maxwell Howard Maxwell 1 year ago I think an intro to the emergence of spacetime is fascinating and welcome Gilbert ENGLER Gilbert ENGLER 1 year ago (edited) Just excellent. Many thanks. A general question: if the multiverse exists ( pocket universes à la Alan Guth), is the one wavefunction of the universe present in all these universes or only in our universe? I guess probably only in our universe! Fasgorn Fasgorn 1 year ago In my branch of multiverse, you are the best physicist philosophist 👍🏻 John Długosz John Długosz 1 year ago "We'll see in the future if time is not real" Good place to stop. 9 Flowtoolz Flowtoolz 1 year ago (edited) The subjects are super intriguing. But I can't truly follow, even with a master degree in computer science 🙈 1 Ivo Beitsma Ivo Beitsma 1 year ago I'm very happy about your web site glitch because speculative stuff is way more exciting... Especially from a trustworthy source 🎉 1 Michael Richmond Michael Richmond 1 year ago Time is real but does't exist until I measure it. The time I measure is relative time, which I can convert to spacetime. I can then use quantum entanglement, to ask 'The wave function of the universe', to synchronize my spacetime, with absolute 'multiverse' time. #Job done. Nathan Okun Nathan Okun 1 year ago Dividing things up in the universe starts with a low speed limit to make sure that all "computations" in one area are complete before the next area's computations from the same source begin: the "processor's cycle rate" of determining all physical interactions (angles of balls away from a cue-ball hit, etc.). This would also seem to prevent velocity-based faster-than-light travel within the universe, but perhaps not hyper-jumps through an "exterior" space from one point inside our universe to another, since in that case no computations need be made in-between and the two events (going and coming back somewhere else) can be considered independent events with no cause/effect having to connect them. Causality is the big no-no in time travel or faster-than-light motion, so this seems to bypass that argument. Too Bad Too Bad 1 year ago (edited) wow wow wow This Clip is truely master piece Sir. you put back Wheeler-DeWitt in their righteous place consistently and coherently. You explain emergence of time , emergence of space. You put network theory in quantum gravity fittingly like jiggzaw puzzle. you called back not popular Entropic gravity in light. If you can coherently put back Lorentz symmetry in the future , this will be most meaningful quantum gravity and theory of everythings as most call it. I hope u can acheive it Sir although it will be the most difficult job to make it in detail. Stephen Schaefer Stephen Schaefer 1 year ago Would having anti-matter cause anti-gravity? I assume anti-matter bends space the same way as matter. I was just curious about the possibility of anti-gravity. 2 protoword protoword 1 year ago (edited) I watched almost all your lectures on top of your podcast and I remember when you said somewhere in some of your lectures last or before last year: Higgs boson is not god particle anymore, because it has been found! I liked that joke of yours, because I’m atheist myself also, but here is new chalenging question to be considerd: Is entanglement god’s comuniacation? Pillio Zoltan Pillio Zoltan 1 year ago If area is proportional to entropy, and entropy increases in irresponsible processes, that means space must expand when irreversible process happens. Or vice versa. David Steinke David Steinke 1 year ago Love the photomicrograph of the brain’s information inbox: hippocampus/dentate gyrus. Thanks. Dentatedave Julián Epstein Julián Epstein 1 year ago (edited) This program of deriving space and time in kind of a discrete decomposition of H as a network and the clock and all of that, reminded me of the Wolfram program for the ´theory of everything´. I know it´s been really criticized, but do you think that the algorithmic approach to time and evolution equation for the universe has some connection with what you talked about in this video? I´m a math PhD student. The only physics I know is from this youtube series, so sorry for the naivety. John Długosz John Długosz 1 year ago 0:36 but of the Hamiltonion's that have a local partitioning, why would they have to be the same everywhere? A random collection of nodes and edges will describe 3 dimensional space _here_, a patch of 4-d space _there_, disconnected islands of all types, etc. It doesn't make sense to explain isotrophic smooth space existing because every point in space happens to be properly connected to its neighbors to form a 3D mesh. What if just one were out of place? Rather, it needs to be some principle that applies to the nodes as a collection. Barefoot Barefoot 1 year ago So with regards to the Quantum Eternity Theorem, joke or not... wouldn't it be the case that it is only time as a metric that goes from -∞ to ∞? It seems to me that time as a phenomenon is under no more obligation to occupy the entire possibility space of its metric than x is under an obligation to go from -∞ to ∞. x as a metric is also infinite, yet the universe could be finite, so why does the appearance of t in an unbounded equation in any way imply that time itself as a phenomenon is unbound? Also... I sincerely do not comprehend how you could be a block time believer and also a Mad Dog Everettian. The Hilbert-sub-universe ⊗ Hilbert-sub-clock version of emergent time sure seems a lot like block universe, yet you admitted it makes a Mad Dog Everettian sad, and is problematic. David Campos David Campos 1 year ago You mean that the quality of being logical and consistent is not much more than at arms reach. If you try to back track anything, you will need mechanics and emergence...and a whole lot of flexibility. Too Bad Too Bad 1 year ago (edited) by the way Sir , H= h- i d/d lambda looks like some sort of Guage transformation or simply transformation. I dont think it is coincidence. Son Goku Son Goku 1 year ago Can you talk about higher dimensions? DRZEC ELECTRIC DRZEC ELECTRIC 1 year ago Hahaha I love it. “That’s exactly wrong” 1 Milos Marinkovic Milos Marinkovic 1 year ago Time is real, got it! 2 chris tinley chris tinley 1 year ago I'm back lol..got sum catchup ta do lol. Sean Carroll...you are always working so dam hard..just want ta tell ya good job and keep up the amazing wrk!!! Your inspirational!! Michael Cirillo Michael Cirillo 1 year ago I’m a big fan. Have you talked about hawkings no boundary proposal. What do you think ? Fred Eagle Fred Eagle 1 year ago Call it ‘wild dog’ . I don’t like mad dog. Any idea of how to test these ideas? An experiment? Jaskooner Singh Jaskooner Singh 1 year ago I wish I was as smart as Sean Carroll 6 viewer viewer 1 year ago Why does the Universe show us the Wave function in the Double Slit Experiment in either ( well one ) situation i.e. When we don’t look ! ! Is the Universe showing off by showing us evidence of the wave function when we don’t look at the two slits ? ? Falken Falken 1 year ago Haven't caught up yet, just wanted to say nice haircut! 4 Stay Primal Stay Primal 1 year ago Sean please reassure me, Ariel is fine ? he seem's too quiet lately. 3 ET Stalker ET Stalker 1 year ago Sean Thank you . # Scientificbadass ROBERT DUNN ROBERT DUNN 1 year ago It appears that physics is just people with educational degrees playing with their Spiro-tot and throwing dice. aplacefaraway aplacefaraway 1 year ago (edited) Careful Sean, there are some birds right above your head. Thijs H. Thijs H. 1 year ago Is this a rehearsal for your talk on Tuesday 😋? R K R K 1 year ago Sean Carroll got a haircut! Notify the universes!! 4 Rick Harold Rick Harold 1 year ago Awesome Dev ekhande Dev ekhande 1 year ago Sooraj Pancholi is emergent in every CCTV footage. 1 Pineapples Pineapples 1 year ago Locality Of Velocity Energy Toefuy Kon Toefuy Kon 1 year ago You could say that you are me. I could say you are me. I am me and you are you. Then I would go to end of the being. Then you would go to the other end of the being.You would still be me being you. I would still be me being you. There is no where you or I can go an not be you or me. You can not leave the space you are in and I can not leave the space I am in. You can go afar from me. You can take different ways than me.You can come at me from any way you like. Meet up with me. Can you become me? Is that up to you or me? It seems that it would be up to you and I if we wanted to become one another. Jaqueline Vanek Jaqueline Vanek 1 year ago that is frustrating, you never write on cloth Lord Crayzar Lord Crayzar 1 year ago Wordpress is a pain! 1 Toefuy Kon Toefuy Kon 1 year ago (edited) 40:40 48:48 53:53 58:58 1:07:17 1:10:20 Hahahaha What are "we" trying to make? 1