Leonard Susskind: String Theory, Fine-Tuning, and the Physics of the Multiverse

[@rtt1961]

Very good interview. I appreciate how the interviewer let Susskind talk at length, not interrupting. Great.

[@robinsonerhardt]

Thanks!

[@stormtrooper9404]

Prof. Susskind is all too but used to not be interrupted... you know.. students! Storytelling for little kids and bullsh!ting at length! But he is on a thin ice when piers have a questions for him! And his theories (better said hypothesis) are full with holes and inconsistencies!

[@Goldslate73]

I cannot begin telling you how much this was needed. He is the reason I love doing physics, regardless of the momentary difficulties sometimes. Thank you, Rob and thank you, Professor Susskind. You're the best...

[@jozincarnate]

Thankyou, so much Robinson. Having a fresh up to date interview with one of History's giants is, great to see. Hearing the legend Professor Susskind, (who is such an inspiration to me) still show his love of problem solving, critical thinking, and rational mind, is still so much fun for him is just he icing on the cake. I hope any young minds watching, following in Professor Susskind's greatness, get inspired to become modern-day explorers; and to seek out new math and new logic, to boldly go where all mysteries will finally become known.

[@robinsonerhardt]

Thank you!!!

[@jeffjones7427]

34:44 so a physicist is concerned about he/they. Leonard is drinking the cool-aid. University professors are lost. I’ve personally as early as 2003. Humans know what is meant by “what is he made of. “ Stay pc.

[@emptyeff]

I’m commenting now just to say hell yeah Robinson. Susskind is a legend, glad you’ve gotten him on. Also, shout out Jenni’s brambleberry crisp.

[@robinsonerhardt]

Brambleberry Crisp is the bomb, especially when you get a pint with lots of the syrup/jam stuff. Thanks so much!

[@chrisstevens-xq2vb]

Legend? He’s a space bender with 💩 for brains.

[@JerryMlinarevic]

​@@robinsonerhardtTell Lenny that there is somebody out there who could and wants to help. However, due to extenuating circumstances contact cannot be realised by usual methods; only face to face. This situation is critical, which can only be moved forward by Intel ppl.

[@blingpup21]

Lenny is a legend!! Robinson, you’re killing it with these top tier guests!

[@robinsonerhardt]

Thank you!!!

[@sirilandgren]

Lenny!! ❤

[@hmdshokri]

explaining it simple and not distort the core idea is a difficult job, Susskind is a master of it.

[@robinsonerhardt]

He is a great teacher!

[@M-dv1yj]

Or can’t except his folly🤷🏽‍♂️

[@karagi101]

@@M-dv1yjYou mean “accept”? What folly would that be?

[@M-dv1yj]

@@karagi101 accept yes ☺️😂🙏🏽

[@M-dv1yj]

@@karagi101 string theory is in terms of physics a scam. And semi intentional to enrich careers instead of science. As math it’s interesting and useful.

[@Prabhakar-gf2oq]

I am always fascinated by Prof Suskind ,his brilliant intellect ,his humility and giving credit where it belongs and his ability to explain some of the most complex concepts in a way even a person like me can understand make him unique. Given enough time as he says anything is possible ,I pray he will live long enough to see his string theory proven and awarded a Nobel prize.

[@themaximus144]

These new in person interviews have me so excited

[@robinsonerhardt]

again, totally music to my ears!

[@mabaker]

The cat is missing

[@ivocanevo]

I didn't know you existed, Robinson. But you're doing long form interviews of my favourite thinkers, you ask good questions and you're in the comments. That deserves an enthusiastic subscription. Look forward to more.

[@robinsonerhardt]

hahaha! thanks so much! i certainly exist.

[@snjsilvan]

Great to see him again! Thank you, Dr. Susskind for all your work and teachings!

[@robinsonerhardt]

:)

[@NunTheLass]

Such a wonderful teacher. I must have watched a hundred lectures of his over the past 15 years. The submarine metaphor was nice. The universe is the way it is because if it were different, there would *probably* be nobody around to ask why the universe is the way it is. Got it!

[@bernardofitzpatrick5403]

Professor Susskind in Robinson’s clarity and profundity enabling warm crucible of ideas and truth seeking! Quality right there! Prof Susskind the legend. His use of the word “fun” in connection with his adventures in the cosmological wonderland is a testimony to his ongoing, unending curiosity and joy in the search for understanding . Thank you, as always, Robinson.

[@robinsonerhardt]

Thank you as always, too, Bernardo!

[@Adam777T]

I’ve watched 10^500 videos about string theory but this one was the first to explain it in a way that made any kind of sense to me. His examples and stories were excellent. Thank you.

[@robinsonerhardt]

That's awesome!!

[@ivocanevo]

What is the minimal surface area of a region that can contain 10^500 videos of average length?

[@dosesandmimoses]

I enjoy Dr. Susskind’s lectures. Thank you gentlemen for your discussion..

[@robinsonerhardt]

Thanks for listening!

[@AdrianBoyko]

Forget physics, Susskind is genius of common sense.

[@robinsonerhardt]

he's really wonderful to talk to.

[@rlombardo6488]

And forget logic...go with the oxymoron 😂

[@tomdorman2486]

If more plumber would go into physics, we could save the world!

[@SeanAnthony-j7f]

​@@tomdorman2486not really

[@simesaid]

​@@robinsonerhardtGreat stuff, Robinson! I'm consistently amazed at the rapidity with which you have gained such a thorough depth of understanding vis-a-vis the foundations of physics! It's almost criminal that your channel doesn't receive more attention as, and I say this with objective hat planted firmly on my head, your guest-list quite simply represents the broadest, most interesting, and thus ultimately the most enjoyable to hear being interviewed, mix of working philosophers and physicists alive today. And in fact, there is no other channel in all the many and varied landscapes of KZbin that can boast of hosting such a stellar sky of guests! This may, of course, sound somewhat suspiciously like hyperbole, and it doubtless would be but for that "objective hat" remains firmly fixed in place. One brief aside though, Robinson, and this is a very general comment that not only applies to _all_ podcast hosts, but that does so equally, it is _not_ a prerequisite for the conduction of a successful episode that interviewers hold a comprehensive grasp of their subjects particular field or niche of interest. After all, if this _were_ the case, and you _were_ to understand some area or another of inquiry as well as any one guest did, then it would hardly seem necessary to interview them in the first place! So, no, a good interviewer need not perfectly apprehend their subjects research area (and neither would it prove possible for them to), and it is not even a prerequisite that they should have read all of their guests books or papers, rather, all that is required to excell as an interviewer is to hold enough knowledge that he or she can _ask interesting questions!_ Moreover, and possibly even most of the time, _the_ most interesting question one can pose to exceptionally bright people consists of but a single, solitary, word... "why?" Of course it _helps_ if the interviewer _does_ have at least a good grasp of the general issues involved, but for the average person listening in to the conversation - and by "average" I mean "non-technical, big-picture, nicely-kept-garden-sans-weeds, layperson" - were the average listener to ever have their dreams fulfilled by, say, being granted an extended personal audience with, oh, I don't know, say... Leonard Suskind, then with furrowed brow, attentive ear, and earnest tone, "yes, but why?" would be just about all the vocabulary we would require. There are two primary reasons that children ask this very question so often. First, because they aren't embarrassed to, and second, because the fastest, most efficient, way to learn something is to ask an expert "why?". Thank you, Robinson, on behalf of at least this one "child", for not being afraid to ask the smartest people in the room just why the world is... so.

[@spencerwenzel7381]

This has been my favorite episode so far and the best treatment of fine tuning I have ever discovered. Thanks for this Robinson!

[@robinsonerhardt]

I am so happy to hear this. Thanks so much!

[@kdalkafoukis]

I wish to Susskind a long life. He is one of the GOATs. Every lecture that I have watched is mind blowing. Also the fact that he combined complexity theory with physics shows that he looks so far away.

[@CoreyChambersLA]

Cannot deny the unique fiction writing talents of Susskind. Here are 12 alternative approaches or theories that seek to address the same fundamental issues as string theory: Loop Quantum Gravity (LQG): LQG is an approach to unifying quantum mechanics and general relativity without invoking string theory. It posits that space-time is quantized and has a discrete structure at the Planck scale. Causal Dynamical Triangulations (CDT): CDT is a background-independent approach to quantum gravity. It constructs a quantum space-time geometry by summing over all possible triangulations of space-time. Asymptotic Safety: Proposed by Steven Weinberg, this theory suggests that gravity is "safe" from divergences at high energies, meaning it can be described by a non-trivial ultraviolet fixed point. Emergent Gravity: This concept suggests that gravity is not a fundamental force but rather an emergent phenomenon arising from more basic microscopic interactions. Twistor Theory: Developed by Roger Penrose, twistor theory reimagines the structure of space-time, using complex number geometry to unify general relativity and quantum mechanics. Entropic Gravity: Proposed by Erik Verlinde, this theory suggests that gravity arises as an entropic force-a macroscopic statistical effect rather than a fundamental interaction. Noncommutative Geometry: In this approach, the coordinates of space-time are promoted to noncommutative operators, leading to a modified version of quantum field theory that incorporates gravity. Horava-Lifshitz Gravity: This theory modifies general relativity to make it renormalizable by introducing anisotropic scaling between space and time at high energies. Quantum Graphity: This model posits that space and time are not fundamental but instead emerge from a network of discrete, interacting nodes. Spin Foam Models: Spin foam models extend the ideas of loop quantum gravity by describing the evolution of quantum states of space-time as a sum over possible "foams" or configurations. Matrix Models: These models, such as the BFSS matrix model, aim to describe the fundamental degrees of freedom of string theory using large matrices, suggesting a non-perturbative definition of the theory. Holographic Principle and AdS/CFT Correspondence: Although closely related to string theory, the holographic principle and its realization in AdS/CFT suggest that the universe can be described by a lower-dimensional theory, which challenges the need for extra dimensions as in traditional string theory.

[@ldero9520]

This is the best interview I have seen in years about cosmology . Just a big Wow !

[@robinsonerhardt]

that’s so great to hear :)

[@tamjammy4461]

This is a new channel for me. Just wanted to say hi and thanks to both of you. I'm not ,sadly, very mathematically literate,, but I do enjoy listening to those who are talking about the implications of their own research . On that note Leonard Susskind is one of my favourite speakers and it was his name which brought me here. I will however be going through your back catalogue of interviews with great enthusiasm. Ta again.

[@robinsonerhardt]

amazing! thank you so much!

[@irinaratushinskaja7900]

THANK YOU for the segment "What Determines the Physics of the Multiverse"!!! FINALLY I got the theoretical explanation for the origins of the parameters!!! Sweet!!!

[@irinaratushinskaja7900]

Edited by me: [55:58] "The picture of inflation is there are lots of Inflaton fields with different values due to (random) quantum fluctuations. When new bubbles nucleate in the Universe, they inherit the (random) values of those fields, and the random set of Inflaton field values lead to random sets of physical parameters like the fine structure constant etc. inside the bubbles."

[@AlexKleinkanocomputing]

Enjoying the iteration on the production format. And this is a great get. Diving in now.

[@robinsonerhardt]

Thanks so much! I'm having fun with it.

[@chemicalfiend101]

Absolute banger of an episode! Thank you Robinson and keep carrying on with the good work! I hope I can donate to your podcast soon. Keep being awesome

[@robinsonerhardt]

Thank you so much for watching!

[@Nathr5600]

So nice to see the in-person format working well. Very clear and easy to follow interview style, nice job! Keen to see a David Albert in person interview soon! I do miss Pins though 😅

[@robinsonerhardt]

your wish may soon be granted :)

[@ccampo]

Hi Robinson, thank you very much for posting this interview. Professor Susskind is an amazing educator and wonderful physicist. He has such a keen physical intuition and a knack for explaining things - I loved his submarine story! Keep up the great work - you've got a new subscriber (me!). I look forward to watching some more of your interviews :).

[@robinsonerhardt]

thank you!

[@CurtOntheRadio]

I like listening to Professor Susskind. He's done ok for a plumber. Lucky you, Robinson, meeting all these amazing people. I imagine it's often as intimidating as it is fascinating, not least in this case. Anyway, thanks so much. My bedtime listening sorted.

[@robinsonerhardt]

thanks curt :)

[@wyst69]

Excellent interview with a great physicist! Thank you

[@LuciFeric137]

Excellent. So nice that you know when to stay quiet and let the master expound

[@robinsonerhardt]

hahaha absolutely

[@PhysConcept]

One of the greatest minds and a wonderful scientist. Thank you for bringing him up to your podcast. ❤

[@robinsonerhardt]

Glad you enjoyed it!

[@seionne85]

Love this! Thank you so much for having these conversations! A small bit of constructive criticism for you, the volume difference between your podcast and the ads is jarring. I'm not sure if your volume is always low, but this is the first time I've noticed. Thanks again!

[@robinsonerhardt]

yikes! thanks for letting me know!

[@FigmentHF]

Hi I’m not a clever school man but maybe we are all some complex quantum excitations playing out on a lower dimensional boundary and it’s super complicated and has all the ADS/CFT holography stuff and basically those stable, complex agential quantum patterns model their otherwise combinatorially explosive quantum chaos realm with an inferred, constructed, generative model of reality that is a useful course grained approximation of some vastly more complex quantum happenings. I’m high rn. And also this is essentially the “bulk” it’s how we interface with reality, stuff like geometry is an us thing, and fractals and symmetry, it’s basically how our minds construct reality in chunky and intuitive terms that are good enough for evolutionary success. What else? Umm, that’s it maybe. I love Lenny, he’s like a real life legendary demi-god type guy, thanks! Love you guys! :)

[@robinsonerhardt]

Thank you!!

[@greenmountainfarms7515]

Stunning conversation! Thank you.!

[@robinsonerhardt]

thank you!!

[@FirstRisingSouI]

I love how humble he is.

[@superfuzzymomma]

Susskind is my hero.

[@robinsonerhardt]

!!

[@mnrvaprjct]

Please interview Lisa Randall on the nature of 3-branes, the Randall-Sundrum 1 & 2 models are very fascinating

[@robinsonerhardt]

would love to!

[@mnrvaprjct]

@@robinsonerhardt I do hope the opportunity presents itself, that will be a very interesting episode !

[@ShubhamKumar-uv6ri]

Yes, please do !!

[@reimannx33]

​@@ShubhamKumar-uv6ri Of course you want lisa, swami gandhananda.

[@snappycattimesten]

84. Amazing. Having your marbles in old age is a blessing.

[@JoeLebrick]

Yes!!!! I've been waiting for this!!

[@robinsonerhardt]

Me too.

[@dimitrioskalfakis]

brilliant mind with refreshing nuances. great guest.

[@robinsonerhardt]

Thanks!

[@alexjbriiones]

The problem isn't the mathematics; the problem is the testing. As people like Peter Woit have pointed out, it's been 50 years since string theory was introduced, and it still hasn't been properly tested. Another issue is that string theory relies on 11 dimensions, many of which cannot be observed. So, how do you test it?

[@김동욱-g7z3n]

What a profound interview!

[@robinsonerhardt]

Thank you!!

[@GoatOfTheWoods]

Thank you, professor.

[@robinsonerhardt]

*surrogate you're welcome*

[@GoatOfTheWoods]

@@robinsonerhardt 😄

[@andystewart9701]

This was just so good! Such a legend!

[@robinsonerhardt]

So glad you enjoyed it!

[@diegoalejandrosanchezherre4788]

Amazing talk, thank you!! 🙌

[@robinsonerhardt]

Glad you enjoyed it!

[@DanielC618]

4:21 I think I know why Leonard always uses examples with water. It's because water is a more intuitive way to think of quantum phenomena than air, where gravity pulls everything together with less resistance, whereas water buoyancy and the nature of water particle interactions make this medium more akin quantum phenomena where the effects of gravity are negligible. Also, the interconnectedness and malleability of water particles is intuitive to explain particle interactions in a stable medium, where using air would imply more nuance in the explanation. Although not a perfect analogue, helps the layman intuitively understand quantum mechanics.

[@TimZM]

thank you for this one, robinson

[@robinsonerhardt]

My pleasure.

[@mrknesiah]

He’s selling a circular argument…the fact is that if the constants/conditions were different then we would have evolved differently and the submarine would’ve been engineered differently.

[@SOLDIERSOFCHRISTCWO]

Physicists say emphatically that if the constants were different there would be absolutely no life. You're lying. Life can't evolve on any other planets. There's no confirmation of evilution anywhere in this universe. So life cannot adapt to certain environments. Therefore in a chaotic universe where the laws of the universe didn't exist....life would be impossible

[@NickPDX22]

My favorite living physicist even tho I don’t believe in string theory. Funny how he’s an atheist yet he’s proven the existence of a grand creator talking about the cosmological constant.

[@dennk735]

Wonderful guest!

[@robinsonerhardt]

thank you!!

[@monkerud2108]

Just as a simple conceptual example, we can take two situations, the double slit experiment, and a bell test. The variable dependence is different in each case, and there is no issue accounting for the double slit in a deterministic way, but if you want to put it into a framework where we are summing over real possibilities for what the deterministic system might be, and therefore what it might do, you obtain the correct resulting probability distribution over observables, ect, you need the individual deterministic states summed over to have some very soecific properties, the double slit is a nice illustration of how it works with regards to interference of amplitudes, in a typical set up, you will for instance produce minima, which might be at 0 luminosity, and the average containing a 0 means that whatever happens no states, or states with probability density 0 over all the possible states must produce a measurment corresponding to that 0. The statistical properties puts constraints on the dynamics of the set of deterministic states summed over.

[@monkerud2108]

With the bell experiment, we have to explain a very particular spin correlation, and we do that by supposing that in any state that is allowed to be summed over, the dynamics in some way must force the corrections, in a bell test with simole settings, this is easy, first you just suppose that a pair of entangled particles with anti correluspins, has an actual orientation all along, then you suppose that when one spin interacts with a field of a certain strength it has a probability density in time to interact with it and get entangled with it, and when that happens sufficiently far away that the other particle is not interacting with the same field, the field configuration holding the two spins correlated snaps of in a way and once the lost signal so to speak at the other end reaches the other particle it is rotated to compensate from its departure from equilibrium when its connection was broken, this causes the 2nd particle to be oriented opposite of whatever orientation to first was measured to be. Then we are left with a single particle with a known spin in a single direction, and the maths giving you the probability for up or down in each possible orientation of the measurement apparatus is identical as if you just prepared a single spin in a known state of up in some orientation. Such a force could be instantaneous in its action, in which case it just gives you ordinary quantum predictions, or it could be mediated by something slower but still faster than Light by some margin that makes experiments done so far come out the same. The important thing about this example os not that it is true or that this should convince you that this is true, it is just the simplest description in words of the action that would be necessary to set up the right forcing of correlations through the dynamic of any history we could sum over. Any choice in any lab and their combination correspond to a deterministic sequence of events and all of them could have one or many states that could deterministically evolve to give the right statistics when summed over. This is the kind of summing over histories you need to build a statistical theory for extending quantum mechanics. In the case of a bell test, all this force does is exactly what needs ti be done to leave the randomness when measuring off an axis for which you know a particle is prepared with certainty identical independently of how it was created, such that local environmental factors can account for the dice rolls locally, but the forcing of the correlation is always there in the dynamics. I think we need a broader framework to analyse these kinds of implications from Quantum mechanics into a statistical theory, by providing a sketch of what kinds of microscopic dynamics is necessary to make them come out right, i think if we dont have such a coherent picture it is hard to evaluate what the questions mean, i agree with that, but i think it is more than possible to produce such a sketch for all quantum properties. And also possible to construct rigorous and more realistic theories, that is what i'm working on.

[@david-joeklotz9558]

Superb interview 😎

[@robinsonerhardt]

Thank you so much!

[@alexgoldhaber1786]

Good interview.

[@VikingOlberg-NymoenOfNorway]

I really enjoyed this. Thanks

[@sabotagesabotage7927]

In general, I like that Leonard gets into the nitty gritty of these ideas

[@swyveu]

extremely well done!

[@robinsonerhardt]

Glad you liked it!

[@user_375a82]

I really loved Susskind's Holographic Principle - to me it makes perfect sense. A 3D plus time space projected from a Bekenstein 2D surface in a black hole. This means that there is no matter or photons they are merely data projections as in a hologram from a 2D surface. Then you have a quantum reality and a 3D physical reality. The quantum reality has no distance or time component and everything is projected from this 2D spherical surface making a 3D physical space that has a classical and a quantum space. The quantum space that is informational. Explains most things. I don't know what's "outside" that but imo you only need a rotating black hole and it all follows. Even intelligence follows naturally, it evolves easily. Even chemicals evolve (Cronin Theory) easily. L. Susskind got it right I think. Well, I heard the theory from Susskind but he doesn't talk about it now much, sadly.

[@hartejdhiman4438]

Leonard Susskind is the last of a kind of physicist who is a credit to mankind.

[@maryammobasser7262]

True to ourselves is a must!

[@1970jaw]

Very interesting. Many thanks.

[@robinsonerhardt]

Thank you!

[@Robinson8491]

Love this man

[@robinsonerhardt]

:)

[@academicresearch2280]

Thank you.

[@robinsonerhardt]

You're welcome!

[@Giantcrabz]

A breath of fresh air among pop-sci cranks spouting gibberish about quantum consciousness giving us free will somehow

[@allantaylor420]

Cool, watching from Brazil

[@robinsonerhardt]

great!

[@virtualvessel0]

A more differing Cosmological Constant would lead to "immediate expand-collapse" in so collapsing "re-tuning" of the Cosmological Constant occurs until exponential expansion, Inflation-theory takes off, leading to Big Bang itself allowing particle-constants to settle differently in each "bubble universe".

[@paulrecher]

In 'Just Six Numbers', Rees computes for a universe in that suite of universes that can evolve sentient life to talk like we do requires stable atoms, suns, and black holes. The odds of being such a universe is calculated at 10 to the minus 243. PS This # is alot lower than the odds of your unique birth.

[@Seekthetruth3000]

Good info, thanks.

[@robinsonerhardt]

thanks :)

[@tonywestbrook9876]

That was really, realy cool! 🏁

[@robinsonerhardt]

Glad you liked it!

[@timewalker6654]

After long time seeing susman in talk

[@robinsonerhardt]

long time indeed

[@sillygoofygoofball]

Thanks!

[@robinsonerhardt]

oh, wow! thank you so, so much!!!

[@tim57243]

I would be very interested to watch a discussion or debate between Susskind and Turok. Turok apparently thinks the Standard Model cam be made to solve the problem eith minor revisions. Judging by the portion of this video I have watched Susskind expects the solution to be string theory + anthropic principle.

[@Joshua-by4qv]

If Susskind doesn't understand QM, then I am off the hook. Phew. I feel less stupid.

[@robinsonerhardt]

yes we can all give up now :)

[@david-joeklotz9558]

He understands QM. The issue is connecting QM to Relativity, which string theory does. And the ‘measurement problem’ which he referred to mentioning Everett’s work. But don’t for a minute believe he does not understand QM as it is. The puzzle is the foundation question. Prof David Albert would be a great future guest. Prof Susskind mentioned ‘Andre’ and that has to be Andre Linde. Hopefully another future guest 😎

[@KirilIliev_Utube]

Yes, Susskind is legend

[@robinsonerhardt]

:)

[@raffinee_3763]

A national treasure...........

[@robinsonerhardt]

!!

[@oliverjamito9902]

Pop Leonard thank you! For thy visitation to comfort the COMFORTER and thy attending unto our OWN. Love you Pop! Gratitude and Honor! At least thy Son can do is to washed thy FEET to let ye know the mileage from thy feet is recognize!

[@LateNightVideozz]

I don't know why but hearing this felt not so sensical or in anyway provided valuable information.

[@heywayhighway]

Amazing

[@robinsonerhardt]

Thanks :)

[@Rayleigh-ol6kw]

Susskind's professorship is named after Felix Bloch.

[@robinsonerhardt]

!

[@nasirfazal5440]

String theorys' mathematics sounds like intelligent designs of human mind..Prof.Dr.Nasir Fazal Cambridge USA

[@Danielm103]

Leonard is awesome, I’ve watched all his lectures ... while eating cookies

[@isitme1234]

Good man

[@robinsonerhardt]

:)

[@csbarolaca1]

Extra-Dimensional Collapse Hypothesis hypothesis involves an extra-dimensional collapse. Here’s a detailed look at what it might entail and its potential implications: Concept: Instead of collapsing within our familiar 3D+time framework, the collapse occurs in a higher-dimensional space. This collapse in extra dimensions influences our observable 3D+time reality, determining the outcome of quantum events. Advantages: Might provide a more intuitive explanation for the probabilistic nature of quantum mechanics. Could potentially unify quantum mechanics with general relativity if extra dimensions play a role in both. May offer a new way to address the measurement problem, suggesting the observer effect is due to interactions in higher dimensions. Challenges: Lack of empirical evidence for extra dimensions. Current experiments at scales accessible to us have not detected extra dimensions. Introducing extra dimensions adds complexity, which might not be necessary if existing interpretations suffice. It requires a rigorous mathematical framework that fits with known physical laws and experimental results.

[@arturoeugster7228]

To make a stable submarine add a feed back control system or notice that passive stability can also be done with different pressure dependence of the sea versus the average density of the summarine volume. This is so simple, so very simple that only a child can do it... by driving an unstable bicycle.

[@Frisbieinstein]

An experiment to test the anthropic principle? The mind boggles.

[@zhavlan1258]

Request to you❤: Suppose: we managed to “improve” the Michelson-Morley experiment so that with its help the result of the experiment was determined; speed on an airplane is 300, 350, 400 meters per second. Question for you: what will this mean for BIG SCIENCE?

[@monkerud2108]

Idk about the universe having to be deterministic a priory, i dont think logic can do that for you, but i think there are good reasons to believe it could be deterministic. First the the quantum predictions are all acceptably solved by supposing that the variable dependence that exists for measured outcomes are put there by ordinary interactions is a part of the substructure physics where influences are propagated a lot quicker than light, then it is possible the concive of conceptually simple ways to put it in deterministic framing and extending current theory by doing so, it then is possible to suppose a distribution of evolving states which each has the correlations that are non trivial bakes into the dynamics. Then you can do it, then its just like summing over histories for any old fashioned statistical mechanics problem. Gerard is smart and seemingly a nice guy, i agree with him. Although the foundations you need for dealing with the issue of producing such a theory has not been put forward by anyone as of yet, but i think ot is possible to make a lot of progress on it.

[@dougg1075]

Love this guy. Like the guy down the street but a genius. And a plumber

[@SarahL-d1q]

PHYSICS GOAT

[@robinsonerhardt]

!!!

[@km40343]

What is the prediction of cosmoligical constant from the string theory? Did it changed from the earlier bosonic string to branes?

[@lepidoptera9337]

Pretty much whatever you want it to be.

[@anishmukherjee94518]

In that case should one think about the twistor theory? Should one spend time to find cosmological constant from twistor theory by Sir Penrose ?

[@reimannx33]

Lenny looks to be in great shape.

[@alexmonras1572]

Those fluctuations that give rise to the nucleation of bubble universes, if they come from quantum mechanics, they need to come by through a measurement process. That's the only way randomness manifests itself in QM. Without observation, the evolution is perfectly deterministic. Therefore, the question begs itself: who or what is the observer? Unless those bubbles are in a superposition of existing and not existing....

[@CharlesSagan1]

Beautiful 🧡

[@robinsonerhardt]

Thank you! 😊

[@TheMemesofDestruction]

Professor Suskind is pretty Cool. 😎

[@robinsonerhardt]

😎

[@quantumkath]

Leonard Susskind gives us the BEST idea ever!

[@robinsonerhardt]

Which one?

[@quantumkath]

@robinsonerhardt I know! I am revising it to, "Leonard Susskind gives us the BEST ideas ever!"

[@portalsandmagicghostnumbercube]

An amended Invisible/Holographic Principle of the Multiverse I propose not one but two bounds, two horizons, two principles, one nested within the other and spanning out from and holographic universe and into the invisible multiverse, beyond our cosmic horizon. Two sides of the same coin, but one inverse to the other inverse to the other. A duality within a duality. The bulk/brane holographic universe exists within the Inverse boundary of another invisible multiversal principle. If you turn an invisible object outside-in, you'll have a holodeck-like volumetric holography, a bulk within a brane boundary. If you turned the same holography inside-out, you'll have only one invisible exterior reality to blend into. This asymmetry between the inverse invisible object and holodeck seems to require a multiverse of infinite possibilities, choices for the holodeck to blend into, in other realities. These ideas are all based on my research into invisibility and holodecks. Which seems to have its parallel in an Invisible/Holographic Principle which includes two principles, the holographic principle and an invisible principle. You don't make an object invisible. You make the space that the object rests in, invisible. Invisibility is a real and dual aspect of a complete picture of reality. Universal and multiversal. Instead of submarines, I've imagined a portal-friendly reality. Each universe is portal-like within a much larger multiverse landscape, invisible to each other beyond their respect invisible/holographic horizons. There are three types of portal techniques, technologies and hyper-technologies for Photographic Portals, Televisual Portals and hypothetical Cosmic Portals, respectively. I'm currently working on a small scale mock up model of a low-tech Photographic Portal. These are the simplest kinds of portal using photographic techniques. Beyond that are Televisual Portals, which would use optic electronics and modified light-fields. Beyond this is anybody's guess. A hyper-technology for a Cosmic Portal. They all differ in how encompassing they alter the reality they're in. Photographic, Televisual and Cosmic Portals and an Invisible/Holographic Principle of the Multiverse, all backed by an inverse relationship between invisibility and holodecks.

[@nishthasharma8642]

I have nothing to do with physics but i know the term string theory because of The big bang theory😂 Sheldons' professor was always working on it

[@Tesla_Ampersand_Friends]

16:49 it's been (much) more than 25 years (even for the characters dr susskind dables w) but there is an alternative idea that could have sense made of it. Essentially an eternally repeating cycle of expansions and contractions for lack of better verbiage.

[@levani7851]

Audio is so low.. pls bump it up in the future

[@diegoalejandrosanchezherre4788]

if you have a new oportunity to talk with him, you should ask him about the consistency betwen the "covariant bousso bound" and he´s conjecture "quantum complexity=volume", i think there is a little tension between theese two conjectures (where all this new quamtum information of the growing volume is stored)?????

[@karlpetersson3007]

The Cosmic Landscape link 🔗 seems broken?

[@Achrononmaster]

Well,... I guess you cannot read all the papers. @17:40 and @21:12 and @29:50 --- if Lenny read Turok & Boyle he'd know there is one approach to the cosmological constant which does not (yet) fail. The CPT Symmetric Universe proposal. Their package of ideas does hinge on the RH neutrino being dark matter, so the lightest neutrino must have zero mass, which will be tested accurately enough soon (within a decade). It is a critical aspect of their account of dark energy, and is tied up also with Boguliubov zero-dimension scalars which cure the three energy problems: Weyl anomaly, trace anomaly, and vacuum energy anomaly. This also hinges upon the Higgs being a composite particle, not elementary, which will also be tested (though no one I have heard knows quite when).