The Science of Time - Carlo Rovelli

Try AG1 today: www.drinkAG1.c...
For early, ad-free access to videos, support the channel at / alexoc
To donate to my PayPal (thank you): www.paypal.me/c...
VIDEO NOTES
Carlo Rovelli, an Italian theoretical physicist, is known mainly for his contributions to research in the field of quantum gravity.
He is the author of:
Seven Brief Lessons on Physics: amzn.to/3Vpsjvc
The Order of Time: amzn.to/3VvzbXJ
White Holes: amzn.to/3vfBhR7
TIMESTAMPS
00:00 The Confusion Around Time Zones
05:05 Explaining the Concept of Universal Time
12:51 Is Time-Relativity Too Negligible to Measure?
20:31 The Correct Way to View Time
29:43 Heat’s Role in Memory & the Past
36:07 Why Can’t We See the Future?
44:07 Describing the Experience of Time
49:11 Why Do Objects of Great Mass Have an Effect on Time?
57:43 Gravity & Time Are the Same Thing
1:02:30 Carlo’s Book
CONNECT
My Website/Blog: www.cosmicskept...
SOCIAL LINKS:
Twitter: / cosmicskeptic
Facebook: / cosmicskeptic
Instagram: / cosmicskeptic
TikTok: @CosmicSkeptic
The Within Reason Podcast: podcasts.apple...
CONTACT
Business email: [e-mail]
Or send me something:
Alex O'Connor
Po Box 1610
OXFORD
OX4 9LL
ENGLAND
------------------------------------------

[@CosmicSkeptic]

Try AG1: www.drinkAG1.com/withinreason | For early access to episodes, ad free: www.Patreon.com/AlexOC

[@KermitsBadFurDay]

I really respect you Alex but I believe you asked the wrong question in this interview. The question isn't "why can I remember the past and not the future". You can't remember the past, you can only remember your past. This is because we do not have some innate ability or sense to detect what has occured in the past. Our knowledge of the past only comes from gaining knowledge of the present and then storeing that knowledge in our brains to be accessed agian later. We have NO more access to the past than we do to the future. We only have access to the present. The past and the future are not the left and right of time. The states of time are "flowing" or "not flowing". Science proposes the potential to slow or maybe even reverse this flow in specific conditions. But having access to the entirety of time is a misunderstanding of it. As you will have noticed by my awful spelling and grammar I am just some random idiot though so what do I know. This is just my best guess from what I have learned.

[@DonG-1949]

YOU sir are a CHARLITTAN and a FOOL!!!

[@L17_8]

​@@KermitsBadFurDay Jesus loves you ❤️Please turn to him and repent and receive Salvation before it's too late. The end times written about in the Bible are already happening in the world. Jesus is the son of God and he died for our sins on the cross and God raised him from the dead on the third day. Jesus is waiting for you with open arms but time is running out. Please repent and turn to him before it is too late. Accept Jesus into your heart and invite him to be Lord and saviour of your life and confess and believe that Jesus is Lord, that he died for your sins on the cross and that God raised him from the dead. Confess that you are a sinner in need of God's Grace and ask God to forgive you for all your sins through Jesus. Jesus loves you. Nothing can compare to how he loves you. When he hung on that cross, he thought of you. As they tore open his back, he thought of your prayer time with him. As the thorns dug into his head, he thought of you spending time in the word of God. As the spears went into his side, he imagined embracing you in heaven.

[@Multiversalelevations]

Your confusion. Not everyone else. Another “expert” . Waste of time.

[@KermitsBadFurDay]

@@Multiversalelevations are you talking to me because you didn't say this as a reply? I didn't claim to be an expert, I said I wasn't. But if you where talking to Alex your comment makes even less sense lol.

[@lrvogt1257]

Mr O'Connor. I am 75 and become a great admirer of yours. To mangle Churchill... Never has one so young gotten so much out of so many. Your interviews are masterful as are your commentaries and debates. You are a remarkable individual and I am eager to follow what I expect to be an exceptional career.

[@KieranLeCam]

What a nice comment, perhaps you are the masterful one. ❤

[@MelFinehout]

I remember forecasting it when he was, I think, 16.

[@DonG-1949]

he is a NARCO and a GOVERMENT PLANT

[@mclaytv]

Me being absolutely in luv with Alex. I would just like to say: Just his video on Jordan Peterson is the best explanation on what Jordan says he believes. I’ve being trying to understand for 3 yrs what Jordan believes and couldn’t figure it out until Alex’s video. That being said everyone one of us whether atheist or religious should be way more complimentary towards other humans. I do not have a “scientific” reason for why it is important but it is. As Jordan might say “transcendent”.

[@L17_8]

Jesus loves you ❤️Please turn to him and repent and receive Salvation before it's too late. The end times written about in the Bible are already happening in the world. Jesus is the son of God and he died for our sins on the cross and God raised him from the dead on the third day. Jesus is waiting for you with open arms but time is running out. Please repent and turn to him before it is too late. Accept Jesus into your heart and invite him to be Lord and saviour of your life and confess and believe that Jesus is Lord, that he died for your sins on the cross and that God raised him from the dead. Confess that you are a sinner in need of God's Grace and ask God to forgive you for all your sins through Jesus. Jesus loves you. Nothing can compare to how he loves you. When he hung on that cross, he thought of you. As they tore open his back, he thought of your prayer time with him. As the thorns dug into his head, he thought of you spending time in the word of God. As the spears went into his side, he imagined embracing you in heaven.

[@jsmit9484]

"thank you, it was remarkably nice" is such a great compliment. Can't help but feel insanely proud of Alex and what he had achieved

[@jsmit9484]

@mind5403 Been watching all of his content for many years. Does that really fit the meaning of "not knowing someone" to you?

[@sordidknifeparty]

Why do you feel proud of alex? Did you have some hand in his success? Perhaps you mean you are very impressed by Alex and what he has achieved

[@jsmit9484]

@sordidknifeparty Why do I need to have partaken in someone's achievements to feel a sense of pride? A lot of people feel pride when their country's soccer team wins the World Cup. Have any of them contributed anything to that succes?

[@AbhikChakraborty1]

Deutsch, Dawkins and now Roveli... I can't thank you enough for bringing these guests.

[@amihartz]

Sadly, Deutsch is an outright fascist who advocates for ethnostates and industrial scale genocide of minority groups.

[@MindShift-Brandon]

Amazing! The Order Of Time is one of my favorite books of all time! I am a huge fan. Thank you for the great conversation.

[@Steven_Dunbar]

Your videos are awesome 😎

[@benhatke5110]

INCREDIBLE. Not only are you interviewing one of my all time favorite authors, but in 2 months, for my next book, I am embarking on a circumnavigational journey (without flight) and will lose that mysterious day.

[@Myshcan]

You will lose that mysterious day but if you kept track of the hours, you wouldn't lose any hours. Would you?

[@Lousysuperior]

@@Myshcanyes I think they could loose hours, depending on where they are and how fast they are traveling

[@David_Groves]

@@Myshcan Assumptions: Travel at speeds at which relatavistic effects are negligable. Your circumnavigation is westwards. Daylight savings is ignored / you travel at a time it doesn't change. Therefore: 1. Track time on your watch: You lose no hours. 2. Track time by the time/date on clocks in the places you visit: You lose or gain 24 hours, thus losing or gaining a day. Each time you cross a timezone, you "lose " an hour, and in circumnavigation you lose 24 of them, thus a day.

[@Myshcan]

@@David_Groves No. 2 is an interesting alternative approach. Sounds kind of like saying when I took a flight from NY at 1:00 p.m. EST and arrived in SF at 2:00 p.m. PST, the trip only took 1 hour.

[@johnsilfen70]

@@LousysuperiorIf they come back and analyse it, they going to loose a day little by little but once they pass the date line and it is all come back and the loss is not existing according to the calender when they are back at the start. However counting day by the passes of sun lit days the loss is obvious!

[@jadgf]

Two of my favourite people on this world talking about physics. Couldn’t ask for more

[@ogi22]

Oh yea, that was a huge and wonderful surprise 😁

[@proddreamatnight]

These are the types of conversations I crave to witness on this platform, thank you for your work Alex

[@ValentineBondar]

You are a brilliant interviewer. Your guests shine because of your quick witt, and great listening skill. You’re well prepared, you create space. Like Carlo said “Remarkable conversation”

[@shweshwa9202]

Grande Carlo. And congrats to Alex to have managed to interviewed him. I understood probably 10% of the interview but I’m still blown away about it.

[@MrGilRoland]

Same. The concept that time is just an effect of gravitational waves is literally what make me recognize time as a real thing for the first… time. That is part of the 10% I understood, and the best explanation about what time is I’ve ever heard.

[@voltydequa845]

@@MrGilRoland Less you understand, more you admire.

[@randomacc246]

@@voltydequa845it really is

[@alessandrovimercati8449]

As an Italian philosophy student and great admirer of Dr.Rovelli, i'm so happy to see him on this podcast! His books are absolutely must-reads to find the beauty and poetry in the world of physics.

[@joannware6228]

Could you give some examples of the beauty and poetry? Is it objective beauty and poetry?

[@voltydequa845]

@@joannware6228 Ah ah. No, he cannot (as we can see). The aspiring philosopher does not seem able to ask (himself) the simple question if those readings are useful to +understand+ the world of physics. And btw that's why he uses the vague "find the beauty".

[@lucanina8221]

I knew about relativity as an amateur but the fact "We fall towards the direction of where time goes slower" is just wow

[@garyrolen8764]

It's certainly an interesting explanation for gravity. I wonder if this thought will solve the problem of dark matter.

[@bedro_0]

@@garyrolen8764 I don't think so. We've known that since the discovery of relativity.

[@JonTonyJim]

I dont understand why though. Why does something going slower have an inherent pull?

[@bedro_0]

@@JonTonyJim I'm just gonna copy-paste the comment I made on this vid earlier: The analogy I like better for demonstrating the curvature of spacetime is the following: Imagine a flat plane of conveyor belts, where all of them move in the same direction, but the speed of each belt increases as you go further from the beginning. If you place a large object on such a plane, large enough to span multiple conveyor belts, the object will ultimately end up on the slowest moving part of that plane. This is because the faster moving belts would rotate and push the object towards the slower part of the plane, repeatedly until it hits the stationary belt, or the slowest one.

[@JonTonyJim]

@@bedro_0 but that seems to me to assume that the conveyor belts all push towards the slower ones. Whats stopping the belts from pushing outwards and the object ending up on the fastest one?

[@ogi22]

Alex, you are simply first class. This was one of the best talks about space, time and gravity I heard recently! Going straight to my physics favourites 😁 Thank you for making such interesting content.

[@thesecondcoming000]

I LOVE LISTENING TO YOUR MORE SCIENCY PODCASTS AND GUESTS. DO MORE PLEASE.

[@cooscoe]

Yet another introduction to a figure that I really need to dive into! Thanks for this thought provoking interview.

[@j0b01231]

Fantastic interview with a fantastic interviewer and a fantastic interviewee. Keep it up, Alex.

[@collectorofthings111]

I have been so curious about time recently, thank you for this!

[@rogerkearns8094]

I make it nearly half six, mate. ;)

[@DenKulesteSomFins]

What do you mean "recently"? 😜🤣

[@kingduckfilms]

Loving the recent episodes with physicists! Keep it up!

[@nwashor]

Hi Carlo. I’m a recent, huge fan of yours. I read White Holes and I’m now reading The Order of Time. I believe you are one of very few physicists that actually understand how time works. And you have an elegant way of explaining the complex in terms anyone can understand. White Holes addressed some thoughts I’d not even considered, and I’ve considered a lot when it comes to time. When Alex asks the question (36:38) about why a human can’t remember the future, we can only remember the past, I believe you missed the mark. You talked about heat equilibrium, which I agree this universe generally disperses heat rather than consolidating it (possibly other universes consolidate it rather than dispersing it - we don’t know this for sure we can only hypothesize), but I don’t believe that’s the only reason humans can’t remember the future. I believe the reason humans can’t remember the future is because the future has not occurred yet, and for that matter the past no longer exists either. The only thing that actually exists is the present moment tor every singular particle. Yes, as you know, events happened, but I believe they no longer exist other than in the marks that they left behind on the universe around them. Whether for example that’s in our brains as memories or whether that’s in craters left when asteroids collide with the earth, or any other effect that is left behind by a cause for that matter. Since the future has not occurred yet, it has left no mark yet for us to “remember “it by, the future cannot be remembered. I believe the only moment that exists is the now - the present. The past no longer exists (accept in the marks it left behind), and the future does not exist yet. The present moment is a moment of constant change, transitioning from a set of infinite possibilities and transitioning to another set of infinite possibilities. Reality is sandwiched in between. Every single tiny little particle has a set of probabilities that it could do in the future. For simplicity sake, for example, the particle might go up or down, left or right. It’s even within the realm of possibility for a particle to go back to the state that it came from. Computer scientists in a laboratory have shown that for single particles, we can “rewind time”. They’ve done this with quantum bits. It is possible to rewind time for single particles. But what does that actually mean? Does it mean that the particle goes back in time? It leaves our universe to the one in the past? No. The particle stays within this constantly changing moment of time that we call the present. It just goes back to the state it was in in the past. There is no past that exists for that particle, but there is a recollection of where it came from. So I hope this explains why I believe you missed the mark on that question. And please correct me if you believe me in error. Thank you.

[@alleneverhart4141]

Time code 7:35 - Carlo misspeaks. "The one (clock) that has been higher indicate(s) less time." In fact, it is exactly the other way around. The clock upstairs runs fast so it will indicate more, not less, time. I'm sure Carlo knows this and just misspoke but for your viewers I think it important to clarify how gravitational time dilation works.

[@I.Reckon]

No, Carlo is correct, the clock on the satellite runs slower than the one on earth. The astronauts on the space station age more slowly than people on earth.

[@alleneverhart4141]

@@I.Reckon I disagree. Carlo was not talking about satellites nor the ISS - he was talking about clocks that are stationary with respect to each other but separated by altitude. For things in orbital motion there are two different competing time dilation effects - a speed up due to the lower gravity at high altitude and a kinematic slow down due to orbital velocity of about 7 km/s. The altitude of the orbit matters. For the ISS there is a net slow down, for GPS satellites there is a net speed up. Here's a quote from the wiki page on Gravitational time dilation: "Clocks that are far from massive bodies (or at higher gravitational potentials) run more quickly, and clocks close to massive bodies (or at lower gravitational potentials) run more slowly...." Carlo just misspoke.

[@I.Reckon]

@@alleneverhart4141 I think you are right, but does he just misspeak, or is he wrong. He also conflates time zones into his explanation. Does this mean that a theoretical spaceship travelling close to the speed of light in low earth orbits would experience time more slowly than if it were doing the same sized circles, at the same speed, in open space, away from a gravity mass?

[@Existidor.Serial137]

@@I.Reckon you have to calculate which one "wins". Which one has the stronger effect: gravity time dilation or speed time dilation.

[@I.Reckon]

@@Existidor.Serial137 Yes, I believe that you are correct.

[@antdgar]

Low-key mind blowing at the end

[@tomer2724]

Wow, truly a great interview. Great work picking interesting topics to talk about

[@olavrask9729]

Thank you once again Alex for eye opening content

[@Doozy_Titter]

Oh nice🎉! Prof. Carlo Rovelli is one of my favourite physicists, along with his friend Lee Smolin

[@matthewjames9209]

Great conversation as always.

[@mitsterful]

This was a fascinating interview and I think you did a brilliant job of asking (as you always do) interesting and thought provoking questions, Alex. I think something that Carlo perhaps forgot to mention which may have helped your understanding is that the relationship between time and heat (or entropy) is a statistical one. The equations which describe the dissipation of energy, referred to in the discussion, essentially tell you that the 'future' is far more probable than the past. This means the passage of time from past to future is actually statistical in nature, and the statistics we use tell us that the future is far more likely to happen than the past (far is an understatement). Brian Greene gives a great explanation of this in a video titled 'Your Daily Equation #32: Entropy and the Arrow of Time'. However, armed with that knowledge, it would have been interesting if you'd asked Carlo what the relationship is between the statistical nature of time that he's describing i.e. its relationship to heat/entropy etc. and the slowing down of time around large masses. I don't know the answer to this and would have been glad to hear Carlo's thoughts.

[@ogi22]

Thank you for the tip on Brian Greene. I'll check it out for sure. And probably get back to a book I red long time ago - "Time's Arrow and Archimedes' Point" by Huw Price. I guess it's time to read it again 😁

[@P-zp4qs]

refers to reality evolving from the least probable to the most probable

[@mitzzzu_tigerjones444]

This is so weird… I randomly watched a speech about white holes this weekend and now you’re interviewing the same person… Amazin!

[@fahimp3]

At 35:45, that is such a deep point... Mind blown! 🤯

[@Knytz]

Im gonna watch this tomorrow while on a plane. What a pleasure and great time to be alive😊

[@ReflectionsofChristianMadman]

I just read this book last month! Glad to see this pop up on my feed.

[@nax1990]

1/Only the present moment exists, and it is constantly evolving as new events and experiences unfold. 2/The past and future are not independently existing entities; they are mental constructs. 3/Our understanding of time, including memories of the past and expectations of the future, is shaped by our subjective experience. 4/Time can be considered as a record of events, but this record is subjective and exists within our minds, not as an objective feature of reality.

[@HcVRGbyOB9CHK0chBKaX]

Great questions, excellent answers, fantastic discussion 👍👍

[@tiredteen8906]

37:43 "There is a sense in which one direction is accessible and one direction is not" Lets call this phenomenon Schrödingers One Direction

[@krcprc]

In a tram driver's course I took, the transit agency taught us the concept of universal time, which the whole network relies upon (necessary for transfer management and so on), and I was like "why are we learning this, isn't it obvious that there is universal time?" It blew my mind that just 25 years ago there were hardly any mobile networks transmitting exact time, so everyone had to rely on their own imperfect watch, which of course didn't yield universal time.

[@abramisme]

Original title "Physicist loses hair explaining physics idea to philosophy major"

[@bigol7169]

33:08 "as soon as it goes down to equilibrium, there is no phenomenology whatsoever that tells you which one's the past direction and which one's the future direction"

[@stvbrsn]

As a lifelong climber, skier and mountaineer it certainly makes sense. It goes some way toward explaining why I seek to spend so much “time” at high elevation, where time goes slower.

[@newjsdavid1]

Great interview 🎊 🎉

[@KieranLeCam]

It's good that you're examining the physics toolbelt of ideas Alex! It's the best thing for a philosopher, just as philosophy is the best thing for a physicist! Two sides of the same coin cannot stay unawares of one another!

[@voltydequa845]

But the physics, and science in general, finished with "Mors tua vita mea" when it comes to talking the talkosophy vs cognitive order (needed by exact science). There were some physicians and philosophers in the past, not nowadays, and there will no be in the future (except some divulgative ones).

[@KieranLeCam]

@@voltydequa845 mors tua vita mea means "your death my life" I'm not sure I get what you're saying.

[@voltydequa845]

@@KieranLeCam The philosophy, especially the continental one, is dying. The need for formalization of knowledge is wiping out the vagueness.

[@KieranLeCam]

@@voltydequa845 I don't understand what you're saying or why it's relevant to my point.

[@voltydequa845]

@@KieranLeCam «I don't understand what you're saying or why it's relevant to my point.» -- In your starting comment you wrote «... just as philosophy is the best thing for a physicist!». Imo it is a nonsense. Same as saying something like "... just as philosophy is the best thing for a carpenter, smith, cook, etcetera, etcetera.

[@mentalhealthmatterswithhwe4095]

Thank you for the amazing video. With regards to how we see time as directional (reachable past but unreachable future), I wonder if it is because we are in a paradigm that does not yet allow us to access the future in a way we access the past. It is similar to how up and down are constants before we discover gravity and are able to send astronauts to space that experiences a different gravitational pull. I'm sorry if this is discussed later in the video since I haven't finish watching it.

[@luker.6967]

Seems like your podcast is become the OG lex with these guests, nice.

[@ourblessedtribe9284]

Thank you! This is the stuff we need right now. A new framing/question of reality. We have heard enough propositional answers. Iain Mcgilchrist would be a phenomenal guest for you

[@ode_ious7510]

I'm actually reading this book for my Metaphysics class this semester!

[@GomuGear4]

If you take some of the statements from this conversation out of context they still sound profound. "There is a time for each and everyone one of us"

[@AlbertStrand-nq4po]

Thank you much Alex!

[@seanrodrigues12]

I've never heard anyone talk about time as well as this or even close. And I watch a LOT of science videos.

[@FFFurken]

The physicist was very patient with Alex 😊

[@aqu9923]

Because he's of our time, one of the most humble geniuses of global stature

[@samsimpson565]

That’s because Rovelli is such a humble, modest guy. Many physicists, e.g. the Lawrence Krauss’s of the world, come across as arrogant and condescending. You can tell that Rovelli has a passion for physics and a wealth of knowledge that he loves to bestow on others.

[@marcomoreno6748]

​@@samsimpson565 I've never found Krauss as arrogant or condescending... simply entertaining and easy going, and excited about what he does. Is there anything in particular he has said which grinds your gears?

[@nathangonzales2661]

Maybe Alex was intentionally pressing for more in-depth explanations. His questions seem almost repetitive, but actually dig into real aspects of the topic. The Ads ticked me off though. Every question!

[@FFFurken]

@@nathangonzales2661Alex is always pressing for in-depth explanations but I thought some of his questions were, well, not very in depth. He didn't seem to be listening (or understanding) enough.

[@bedro_0]

The analogy I like better for demonstrating the curvature of spacetime is the following: Imagine a flat plane of conveyor belts, where all of them move in the same direction, but the speed of each belt increases as you go further from the beginning. If you place a large object on such a plane, large enough to span multiple conveyor belts, the object will ultimately end up on the slowest moving part of that plane. This is because the faster moving belts would rotate and push the object towards the slower part of the plane, repeatedly until it hits the stationary belt, or the slowest one.

[@crazyprayingmantis5596]

How can the speed increase as you go further from the beginning?

[@bedro_0]

@@crazyprayingmantis5596the first conveyor belt moves at speed of 0 m/s, the next onr moves at 1 m/s, the next one 2 m/s and so on.

[@KieranLeCam]

Of course, it's good to remember this is an analogy. It does not bring insight on what actually occurs. Don't wanna be a debbie downer, but don't want people to be mislead.

[@PROJECTJoza100]

I don't understand why it would rotate?

[@phelimkennedy6653]

@@PROJECTJoza100 Imagine a plank across two treadmills. If they were both moving at the same speed it would just move along with it. If however one was on and the other wasn't, one end of the plank would stay still and the other would be pushed along giving the effect of "rotation". It doesn't mean it will spin on the spot, just that the end of the plank on the moving treadmill will not keep pace with the treadmill because it is experiencing a dragging force from the end on the stationary treadmill.

[@pjaworek6793]

Love this guy. Before watching even, time is already weird enough with relativity, it's weird thinking those having fun are truly experiencing our future, weirder still if there was some absolute time keeping mechanism in our human experience.

[@phillipjackson1517]

This one absolutely blew my mind. In specific the part about how we cannot form memories in a state of equilibrium because it wouldn't be equilibrium if we were there with our brains which dissipate heat. And even if we were to be able to look at that universe from the outside, if it were in a state of equilibrium, then nothing is happening, so you also wouldn't be able to form memories from a so called God's eye perspective since there would be nothing to remember since nothing ever happens to be remembered. Crazy stuff to think about.

[@giuffre714]

The only time is now. It's just that "now" changes shape. We count the changes and call it time. 😀

[@robsmith1a]

The past is a place we remember but can't visit and the future is unknown but we're compelled to go there. Having said that many of us try to recreate the past with an ex and seem to forget why we chose a future without each other until it's too late.

[@tristan6773]

brilliant way to open the podcast tbh.

[@dennisobrien3133]

In a reference-less scenario we orchestrate endless references though they are built inside a framework of abstraction. So contingent on our perspective, a perspective built from the heart of time and space. This that looks familiar will also look alien until the looker is seen as itself.

[@GospodinStanoje]

I'm amazed at how quickly, Alex, you're able to come up with a perfect counter-example argument/question every time.(Whatever "time" is heh) This was a brilliant interview. Thank you very much.

[@terry4590]

I like the whole thermal idea. To my understanding i think he was generally talking about energy but like, on a completely different level. very fascinating concept. (LOL IM BURNING UP JUST TYPING THIS)

[@svendtang5432]

This is really mind blowing and interesting…

[@kurtaikido2889]

I always presupposed time was just a measure of decay. Thank you for these insights

[@helencahn7293]

Alex needs to talk to Sean Caroll, the physicist, about his work in emergence. He is embarking on research to describe how the elements of physics result in the world we see and interact with. His podcast is called Mindscape.

[@aidansgarlato9347]

I’m taking a shot every time they say time i’m 1 minute in and i’m plastered

[@Isaac_L..]

Literally in the middle of writing an essay on theories of time (in the movie About Time) for my philosophy in Sci-fi course...

[@TBOTSS]

I would keep away from Carlo Rovelli if I was you. For example he states the following as an argument against the Kalam and the A-theory of time; "Well, cosmological time is a fake. Why? Because matter, gravity slows time so inside the galaxy clocks go slower than outside. Point is there are many different clocks in the universe which they don't agree with one another and there are many times in the universe which don't agree with one another. The idea of the cosmological time is just one arbitrary definition of an average, but I can give a different definition of it." How wrong can someone be?

[@myles5158]

@@TBOTSSI think he’s right. It’s relative in the way we experience it

[@brendanerickson2363]

Thanks for the great content!

[@EccleezyAvicii]

56:11 - _Running into the ocean on a beach_ *Analogy for Understanding Gravity* Carlo uses the analogy of running into the ocean to explain how gravity results from time moving slower at lower elevations, challenging conventional views on the relationship between gravity and time. *Carlo* I have a very silly analogy. You know, you run to the beach, you run into the water, and your feet start sort of finding the water, so they have to slow down. So, your full body falls into the water. Now, it's a bit silly, but it's a bit like that. The reason you're falling down is because, as time passes, you naturally move toward the mass. *Alex* Your feet are moving slower once you get into the water. So, the reason why things fall, the reason why anything falls, the reason why gravity exists, is because time is moving slower at the bottom rather than at the top. *Carlo* That's correct. We can write this in absolutely precise equations. Namely, I can write a space-time picture. We were talking at the beginning about the space-time picture. We can write the space-time picture here, and ask, "Okay, now there's this deformation because time goes faster up and slower down. Now, I ask how a particle or a body, like a stone, could go from here to here in the most direct way." The most direct way is to fall down, not to move straight, but to have this acceleration toward the down, which is what we call gravity. *Alex* That's fascinating. Most people think about this, and I certainly thought about it this way before reading just a sentence that you wrote about this. They'll think that time slows down because of the effect of gravity. That's how we're often taught about general relativity. That was my understanding. It seems like you're suggesting it's not that time slows down because of gravity. Rather, gravity is the slowing down of time, and gravity exists because of the slowing down of time. It's almost like it's the other way around. *Carlo* That's absolutely correct. There are not two different things affecting one another. It's the same thing. *Alex* It seems like the more and more I learn about anything to do with relativity or gravity or time, there's always something new to blow my mind. I guess it makes sense when the whole point of relativity is that these are essentially the same thing. It's all part of the same fabric. But put in those terms, thinking about the person running into the ocean and falling down because their feet are moving more slowly, and imagining that it's just like something like that going on globally, universally, as to why gravity has the effect that it has at all. I suppose conversations like this are helpful to begin to understand what people mean when they say things like, "Oh, you know, time and space, they're just sort of the same thing. They're all part of the same fabric." Everybody knows that's the case. We learned that in school, but it's very difficult to conceive of it and conceptualize it.

[@TheOneMaddin]

I am happy to see that you try to catch up a bit on modern physics. It's unfortunate that this particular quest is not a good explainer, he seems to confuse more than enlighten. But please continue this way!

[@geordiedog1749]

This guy is a legend!

[@TheLeonhamm]

LOL I know I am thick .. as two short planks .. but that 'time' is still a matter of concern not only of discussion strikes me as - odd. Aquinas and the Ancients understood < time > as a relationship, a 'measurement' between two (or more) points in passing (i.e. from a given perspective, e.g. stasis and dynamic, energy and gravity (weight), dimension and space, et al). Our 'level' or attainment of knowledge (still called 'science' today) of the experience of this quirky relationship (in time, through time, with time, outside time, etc) differs largely in degree of measurement (how many beans will make five, and, how long will it take to count them) rather than of kind (physical, mystical, emotional, rational, commercial, national); Dr Rovelli does a remarkably good job in knitting together something like a common understanding of the 'parts' involved, and making a presentable case for the whole = the metaphysics upon which the physics must rest ... or fall apart in confusion. Neat. Keep the Faith; tell the truth, shame the devil, and let the demons shriek. God bless. ;o)

[@providence1961]

29:44 5:05 7:10 9:31 12:52 18:18 20:33 22:19 24:27 28:10 32:41 37:28 44:05

[@kevin042897]

There is great significance to the passage of time

[@intelligentinfinity4768]

What is time the measurements of those earth going around the sun or the feeling of consciousness feeling itself?

[@Sportliveonline]

this guy is amazing

[@glenjennett]

I very much wish I could have been involved in this conversation so as to give my own perspective of how I perceive the illusion of "time". There is so much that I could say regarding everything that was discussed in the video, but it is too much to post in this comment section. I can't say that I agree with everything that was said, but I feel that there is enlightening conversation to be had. I will say this: from my own understanding, the illusion of time is a side effect of gravity and gravity is a side effect of mass. Why this is so is something that no one is able to figure out and it's something that we will most likely never be able to comprehend.

[@smadaf]

About up and down: 1. Even on Earth, the vector that defines down is different in different places. It's the tiniest bit different here from what it is in the next room; the difference is much greater between Alaska and Australia. 2. I wonder whether astronauts in near-Earth orbit with big windows in their spacecraft do have a visual sense of up and down, even in the absence of a gravitational one. I assume that they look out at the Earth and consider it to be "down there", and look at the horizon and consider it to be "out there" or "over there", and look at the blackness of space on the other side of the horizon and say it's "up there". 3. When they get farther away, does the astronauts' visual sense of up and down change. When they head to the moon, do they look back at the Earth and see not as "down there" but "over there" or "back there"? My knowledge, since childhood, of the relatively planar nature of the moon's orbit around the Earth, along with my knowledge that that plane is roughly perpendicular to the Earth's axis, leaves me often _thinking_ of the moon as _over_ there, even though, when I _look_ at it, _sometimes_ (when it's high in the sky, but not when it's near the horizon) I _see_ it as _up_ there. (Indeed, in a sense, I have two distinct concepts of the moon: a sphereoid out there in orbit, and a moving light (of changing shape) here in the sky on Earth.

[@mikefredd3390]

About 31:00. Can’t causality be an “arrow” of time separate from the effect of entropy/temperature phenomenon?

[@trashcat2498]

7:30 Can someone tell me why the clock closer to earths gravitational pull would have more time? If time is passing slower the closer you get to the earths core, then the clock would show that less time has passed, right?

[@vanillaobjective]

huiii omg im so early Alex i love your channel

[@fearlessjoebanzai]

Yes you are coming fast this time!

[@nitinbharadwaj1151]

Getting closer and closer to the Bernardo kastrup interview with your embrace of the subjective.

[@lucasheijdeman2581]

Looking forward to that one! Finally someone who has a radical different view from all people that seem to take models of reality to be reality.

[@joeyrufo]

Is he a Marxist? 😅

[@joeyrufo]

Time isn't a "flat circle"! It's a spiral! 🍥😵‍💫

[@joeyrufo]

A fundamental tenet of Marxism is something called "dialectical materialism." This is a lot different from the materialism you might be used to!

[@roripantsu]

he should do donald hoffman since he actually knows more about spacetime

[@thezieg]

Well done.

[@alexlarsen6413]

Killing some time watching this

[@George4943]

There is another, I think easier, way to imagine proper time. "Proper time" contrasts with "time as a dimension." Proper time is the amount of physical aging which is experienced by an object including clocks and people. The time dimension is good for setting future meetings. Let's meet at Big Ben when it says it's noon and the 3rd of November. In this model the "shaping of space" is modeled as matter density in an otherwise flat space. Consider any arbitrary point. The sphere of all the events which could have possibly affected that point expands at 1sec/sec (proper) of added radius. The past flows in from all directions and then emerges back into the same space it came from. Time's emergence is slowed by the experienced density of matter in all directions with mass's effect reducing by an inverse square law. Time is passing faster in your head than in your feet since the average density is greater there. Matter density also provides downhill and uphill directions. An easy way to go and a hard way to go. It defines geodesics.

[@LOogt]

I have to rewatch this podcast 😅

[@helifynoe9930]

Yes, a clock can be in many times at the same place, all at the same time. Picture a huge mechanical clock, with hands of massive lengths. As these hands are on the move, the further near the end of each hand you go, the slower time is ticking, all due to movement being faster the closer to then end of the hand it is that you are located. And so the ends of these hands are younger than the opposite ends, which are tied to the clocks centre spindles.

[@rotorblade9508]

the universal clock can be though like that: time passes differently depending on position and speed relative to an arbitrary observer. A universal time would mean you could find a place where time was considered as a universal reference for everyone but such place would need to have something special otherwise you wouldn’t had a reason to declare it universal. for example you could say time on Earth is universal but there is nothing special about Earth. An absolutely stationary point would be the perfect place but there is no point in space that can be considered absolutely stationary, there is no fabric of the Universe were objects move relative to it

[@JennWatson]

Hello all from NC USA

[@vortexlegend101]

From arguably the worst guest (Knowles) you’ve had on this show to now one of the best. Very interesting video.

[@kiwiopklompen]

Oh now im curious.. who is Knowles? I saw the Hitchens one - that was just so odd.. when guest behave badly eh. I thought Alex handled that well though.

[@ballisticfish1212]

@@kiwiopklompenhe’s a right wing propagandist basically

[@DandelionScribe]

He had the radical Christian crusader on right after that too

[@iconoclastvii]

​@@DandelionScribeAlex is incredibly good at positioning himself.

[@jacksonelmore6227]

🤔🤔🤔

[@dusty_artichoke]

I have couple of books by Carlo Rovelli that were translated to Czech/Slovak language! Great author, especially the fact he's physicist and philosopher so he's not like i.e. Jim Al-Khalili or Hawking spending time shitting on philosophy but Rovelli is actually engaging with it. EDIT: I made a mistake with Al-Khalili's opinions on philosophy - he agrees about importance of philosophy of science, epistemology and logic, probably along with Einstein, Heisenberg. So not so bad.

[@niblick616]

What physical thing has philosophy ever discovered?

[@dusty_artichoke]

@@niblick616 Is this bait question? I can only give honest one: philosophy lead to many changes in our civilization and culture, but not in physical sense per se. Modern logic, inductive scientific method, major shifts in law and social structure, influences on art and literature, theoretical discussion which lead to many helpful disciplines being established and many more were shaped by philosophy. There are many disciplines like phrenology, eugenics, astrology which died off. Philosophy didn't. It was persecuted across centuries (middle age, Nazi and Communist regimes), sometimes even almost erased - but it always came back. There were always people willing to give their lives for it, for the last 2500 years. Idk, I don't read much philosophy nor engage with it daily but I am kinda frustrated by random people on internet thinking they are bigger then something spanning millennia, continents and eras shaping the culture, politics, arts, law, social sciences, ethics and the way we look at the world. I know philosophy is small in institutional sense - small fundings, small budgets, small faculties, small journals, small number of students etc. but that doesn't mean its not helpful. I hope I sensed your question correctly as honest question for the function of philosophy in our society.

[@niblick616]

@@dusty_artichoke 1/ My question was carefully phrased. 2/ You should understand what informal logical fallacies are, if you have read anything about philosophy. 3/ At no point did I say anything about thinking I am bigger than philosophy. That would be the fallacy of a straw man argument if you were trying to apply it to what I actually posted. 4/ Millions of people used to think that lightning was made by gods. We know that was wrong, no matter how long it was believed nor how many people used to believe it. 5/ It was science, not philosophy, that made the relevant discoveries about what caused lightning 6/ Religions have also been studied for thousands of years and nobody, including any philosopher, has ever been able to demonstrate the existence of any god using at least some of the type of valid and verified evidence I have for the demonstrable existence of my dog. 7/ In many areas Philosophy is science led because science actually does the measuring and acquisitions of basic data that is required to confirm the existence of things that actually exist in our reality. 8/ A large number of modern philosophers generally accept that. In that sense Philosophy is a bit like the caravan of traders that used to follow Roman legions as they moved into and around new countries.

[@smadaf]

3:19 Let's stand in front of a working clock for one minute. During that minute, I'll move my thumb around the perimeter of the clock one time. During the same minute, you'll move your thumb around the perimeter of the clock ten times. If your idea of how much time has passed is times a thumb has moved around the perimeter of the clock, you'll say that somehow ten units of time went by for you while only one went by for me. But we both watched the clock, whose second hand moves at a constant rate, register the passage of just one minute. This is why we measure time by things that move at constant rates instead of variable rates. For many purposes, the rotation of the Earth is constant enough-and we count the movement of the Earth, not the movement of us on its surface. Imagine the confusion that would arrive if we instead counted human movements: you went back and forth between our house and our workplace six times today, but I went back and forth between our house and our workplace just one time today-we agree that what happened is one day, not three days for you and one day for me. This is why we bother to have different words-e.g., "trips" for our movements to and from the workplace, and "day" for a rotation of the Earth. We have to understand that our movements across the Earth are different from its movements about its axis.

[@smadaf]

Astronauts orbiting the Earth who see a sunrise about once every 90 minutes don't have much cause to call one of those orbits a "day". They don't try to cram breakfast, lunch, dinner, work, and sleep into 90 minutes. Their cells are multiplying and dying at a rate that has little to do with how many times they see the sun rise.

[@adrianfeeger]

I love these types of chats... and I mostly follow whats being said but what throws me with relative time is particle entanglement. Say there are two entangled particles a huge distance apart, one gets measured, when was the state of the other determined? Maybe this is what they mean when they say the they need a theory of quantum gravity.

[@enricobianchi4499]

Rovelli goes into a lot of detail on this on his books. What I got from them is that basically every observer is in a kind of subjective universe which gets determined every time a quantum measurement is made

[@haykkhulyan6201]

Fascinating subject. Towards the end, regarding the relationship between gravity and time, I wish you had asked him what this means for an object floating around in deep space, somewhere far between galaxies, with very little gravity acting upon it. What would this mean for the passage of time for that object? And conversely, the effects of an immense amount of gravity, near the event horizon of a black hole.

[@voltydequa845]

«What would this mean for the passage of time for that object?» -- The error is in "passage of time". All this talk is built upon the absence of definition of time. Try to make you own logical / physical definition of (what is) time, and you'll understand better the rhetorical tricks around. Hint: there can be more or less two concepts of time : the one is the clock time, the other is about relations.

[@joratto2833]

The ultimate crossover

[@creativesource3514]

Question: When we say the universe is 13.8 billion years old since big band, is that number correct for all 'observers' in the universe??

[@enricobianchi4499]

I'm pretty sure it's not, great question

[@GeorgeFloyd2023]

My paternal grandmother from the Clydebank's family motto: Carpe Diem. Seize The Day - or better yet "Savour The Moment". Yes! All kinds of profundity to mull over. Zeno's infinitesimals, expanding your awareness, consciousness coordinated with time, the so-called mindfulness?

[@sensorer]

The thing is, the arrow of time is EXACTLY like up and down. The reason objects fall towards the Earth is that their future points towards the Earth(because Earth curves time itself)

[@noorzanayasmin7806]

Time has always fascinated me since I was young. I watched the genie in the bottle movie and how time passes so differently for the genie than human. Watching the moon and it always seems like it is following us everywhere we went. As I grow up and learn the concept of time it becomes even more and more interesting. Heat having to do with time makes sense because anytime you want to travel you need massive amount of energy. Regarding the topic of time moving in only one direction, let's suppose an object is moving so fast that it circle back to the same point and keeps going, wouldnt that make time coming in reverse if certain point of time does the full reversal like this? In this instance it would seem that you could travel in circle in time and potentially go back in time by traveling too fast relative to other people who are traveling slower than you? Am I completely off based here? Someone with more knowledge of this please correct me.

[@enricobianchi4499]

Why would something be able to circle back to where it started by moving in a direction?????

[@Daniel..Lobo..]

Can't believe you brought out one of my favorite thinkers. What a day, what a day...

[@nyakabb2472]

I've waited for a long time for this interview but eixx l now feel like the time is running out😂

[@maratakhmadejev3716]

Nice to see you embrace physics Alex

[@domenico26752]

As a scientist I think what you were trying to convey when asking about the irreversibility of time, was if there is a metaphysical reality underlying the thermodynamical explanation of past and future. In other words: is the linearity of time an artefact/illusion arising from the fact that our very brain works based on thermodynamic effects (therefore time dependant), or is there a non-contingent reality called "time" which by coincidence lines up perfectly with the direction of thermodynamic processes? After hearing this discussion I lean on the first interpretation, I can imagine (even mathematically) that if a brain would be able to work without dissipation processes, then ideally it could remember the future, and this concept sounds very intriguing to me.

[@domenico26752]

@@MarkPatmos good question, we are in the realm of speculation (such as that a non thermodynamics based mind can exist at all, probably the answer is no). So I do not think I can make any reasonable assumptions on such a thing. Certainly in whatever way it would be able to experience past and future in the same way, another question that could arise from such a perspective is how would thermodynamic dependent beings experience an interaction with such a being. Can such a being exist within a thermodynamic based universe, or only outside of it? It would defy the rules of physics, so I am tempted to say it cannot exist within the universe.

[@APaleDot]

@@domenico26752 You may be interested in the field of Reversible Computing.

[@anticorncob6]

You're a scientist saying this?

[@domenico26752]

@@anticorncob6 you pose a question, but it sounds like you are trying to convey a point. Could you elaborate?

[@voltydequa845]

A scientist wondering about the non-contingent reality of time? Sounds strange to me. Reality can only be described in terms of space and time (nothing to do with "spacetime" concept). So the time is a requisite for perceiving / describing / measuring / etcetering reality. Science needs cognitive order. Questions around the linearity and existence of time provoke cognitive disorder.

[@alm7721]

Hey, I don't know if you'll see this Alex. I'm turning 21, I'm extremely confused about religions and the truth of the universe. I believe in God and it makes sense to me that God would send us some sort of guidance while we're here to help us get through the world, but none of the religions seem to be that for me. I'm not sure if it's because I just don't know enough about them, or if Im just wrong. Could you do an unbiased exploratory series of each of the make religions and their core beliefs and problems? I know others have done stuff like this but it's usually a religious person trying to prove their religion is right so isn't without agenda

[@Haytidaho]

This and the problem of the "arrow" of time (why time is flowing "forward"?) have been melting my brains for years... i've read about thermodynamics, relativity, quantum theory and I still feel very stupid about all these issues. Great interview :)

[@AntonioSanchez-yl9wj]

Alex: your question about why do objects… we don’t know. We know that Matter tells spacetime how to curve. Spacetime tells matter how to move. That’s it. If spacetime is not fundamental, it means that it is a property or state of quanta when is out of equilibrium. Think about the universe as the successive events between two states of equilibrium. I make a distinction between quanta and matter or mass. The late one are clocks. In a state of equilibrium there is no mass, no clocks, to time, no scale (size means nothing) that’s the part we don’t understand