Sean Carroll - Is Time Real?

[@kindle139]

Refreshing to know that people have solved the mystery of time, right here in the KZbin comments section!

[@D.A.-Espada]

@lyco46 *facepalm*

[@D.A.-Espada]

@lyco46 I have to disagree. God made us far more complicated than that analogy although it does work on a surface level. I think we are that but there are/is another component/s involved. What that has to do with time I'm not sure but I agree with most of your latter statement. It's as if it's a Being John Malkovich situation except you're under the illusion your in control. I think what we are experiencing is a different thing considering God gave us free will.

[@dickrichard99]

Scientific community said the same shit about Einstein "why are we listening to this janitor?" I'm guessing you have zero thought process of your own probably frustrated about it and took to the comment section to ridicule everyone else's ideas.

[@dickrichard99]

lyco46 The self awareness program you're speaking of is called DNA and a lot of basic instinctual behavior is programmed right into us already and you say there's no god? God and creator are the same thing to me.

[@nicolasdelaforge7420]

good humor

[@Jamie-Russell-CME]

I would watch this but I already watched it tomorrow. My 6 year old nephew used to ask, "Grandma, Is today tomorrow?" He clearly had been referencing the past day when he was told something would happen tomorrow. Tomorrow came, and he had an inquiry.

[@meatmasala2656]

What a thought, man. Awesome

[@dennisgalvin2521]

Classic.

[@golden-63]

"Time is what prevents everything from happening at once."

[@hanslepoeter5167]

Thats a great 2 yr old answer ...

[@TactileTherapy]

@@hanslepoeter5167 thats a bad 1 day ago response

[@golden-63]

@@hanslepoeter5167 That quote was from Theoretical Physicist John Archibald Wheeler, hardly a 2 year old.

[@michaellangan4450]

You still have simultaneity, which is feature of time.

[@michaellangan4450]

@@patrickmulopo7957 Time is the numbering of motion in terms of before and after. Aristotle.

[@JohnDoe-ni9zm]

This whole video flew right past me.

[@Kyanzes]

These talks are very valuable. This channel would deserve tenfold as many subscribers!

[@2fast2block]

Sean has no sense of reality. 1LofT states that energy can't be created or destroyed, it can't happen naturally. One aspect of the 2LofT shows that the universe is winding down, usable energy is becoming less usable. Creation had to be done supernaturally at some point.

[@albell2614]

"Same as it ever was Look where my hand was Time isn't holding up Time isn't after us Same as it ever was Same as it ever was Same as it ever was" I can't seem to understand any more about time than that.

[@tastethejace]

OK, Mr. Byrne. Time to lie down.

[@ScottLahteine]

Sean Carroll My understanding is that what we call "time" is altogether inferred from change, and that we compare the physical changes in one system to the physical changes in a reference system (called a "clock"), and that is where all our measurements of T are derived. Thus "time" is never really observed directly. What we call "the past" is our mental (or any) record of past physical state. What we call "the future" is the physical state yet to be. And, in fact, the part of the brain which discerns the "passage of time" seems to manufacture it by comparing our record of "past" physical states to present physical states, and this facility can be disabled, for instance with DMT, so that "past" and "present" become indistinguishable. (And people find this "timeless mind" to be a very weird experience.) Now, when it comes to perception or detection, of course all perception relies on contrast, and all detection relies on physical contact. If "existent time" is a linear continuum with no cousins, there is nothing to contrast it with, and therefore it is undetectable. If, on the other hand, there is only change, arising in the present from what we might call a "perpendicular" time-line, then in that sense, "time" would be something akin to a "frame" - a threshold of "readiness" at which point the "present" arises before sublimating once more in readiness for the next "present" to arise, and so on. Clearly that is unsatisfactory, but how else can we possibly consider "time" when it really does appear to be a pure inference? Special Relativity requires "T" because it concerns the aforementioned relative physical change, measured against light propagation, and can be taken to say that the observer's physical evolution - their matter - changes less at speeds near "c" - again, physically-speaking, as it proceeds through greater distances, presumably because the spatial propagation of light and the spatial propagation of matter are independent. And yet, something must break down physically at such high rates, because light is electromagnetism, and matter changing relies on electromagnetism propagating with respect to atomic nuclei... I wonder, does breaking it down as purely relative change, or propagation of matter in space, bring any special light (pun not intended) to the situation? Can "T" be replaced with some factor tied more directly to the relative change of discrete physical systems, or does it keep turning up like a bad penny? Another thought or question, related to that... Does electromagnetism bound to atomic nuclei, or within discrete systems, have a different nature, or curl up tighter, or do some extra "magic" compared to electromagnetism freely propagating in less-curvy space in the form of light waves at speed "c"?

[@tthd]

Time is the human way to explaine the first-person present. I love this channel! Pure gold! Robert is a magnicificent moderator/interviewer!!

[@2fast2block]

Sean is pure fiction. 1LofT states that energy can't be created or destroyed, it can't happen naturally. One aspect of the 2LofT shows that the universe is winding down, usable energy is becoming less usable. Creation had to be done supernaturally at some point.

[@atlehman69]

I can conceptualize some really abstract stuff, but when it comes to time I hit a wall. Time, I think, will forever be a mystery to me.

[@nicolasdelaforge7420]

'We treat the past differently from the future but the laws of the universe don't'- finally explains it to me - and why we can sense the future - the universe doesn't treat my next moment as my next moment but has already 'explained' it or 'resolved' it somehow - as being past.

[@Deebands92]

Because ur future is made from your past decisions

[@mycount64]

time is the measure of the rate of change... how we perceive it is more difficult.

[@jorgepeterbarton]

You cant use the word "rate" to define time. "Rate" includes time, its a denominator of time.

[@transcendence619]

Those last two minutes blew my mind

[@TheRealLaughingGravy]

If time isn't real, how come I'm always late?

[@PianoMastR64]

How Can Clocks Be Real If Our Sense Of Time Isn't Real?

[@GeoCoppens]

@@PianoMastR64 This guy Robert L. Kuhn wants everything to be spooky!

[@michaelfrawley171]

We have put a value on time...money is time...when you're late you owe money...time only exists because of money

[@Serenity5460]

@@michaelfrawley171 this is the worst line of argummentation i ever heared XD

[@owencampbell4947]

Laughing Gray, you have your space time on, it's slower than on earth, switch to earth time and you'll be 30min earlier at your job.

[@adamrspears1981]

I am probably wrong. But when it comes to marrying Relativity with Quantum Mechanics, this is how I understand it: Its a lot like a huge, pixelated picture. It you view it from right up close, your brain tells you that all you are looking at is a collage of a bunch of random squares. But if you view it from, lets say 50 feet away, your brain recognizes it as a picture of, let's say Elvis Presley's face. So what's the difference then?? The difference is information! Up close, a lot of information is hidden. So it appears to be just random squares. But far away, those "random squares" reveal all the information. & its immediately obvious that each square is a pixel that forms a portrait of a familiar face. So, this is how I understand how the Macrocosm & the microcosm are married. Its about hidden information, which is Entropy aka "The Arrow of Time."

[@Jamie-Russell-CME]

Sounds like a design feature. Why else would our eye's resolution evolve to work like fundamental matter, as it can be deeply understood. And if the answer is that the concept was there the whole time, I would ask, "Why are we so puzzled by it then?".

[@Knightgil]

That's an incredibly interesting explanation. Thank you.

[@jorgepeterbarton]

I like the conception of how to explain QM. yes the whole idea is that its quantised. Like taking a pixel, but the pixel knows the whole picture even when alone, and only comes into being as the picture. If anything that is what quantised means. If you take only a 'point' out of a wave, we found such 'point' knows the whole wave- it has the information, and cares about information, despite only being one. Unlike pixels of a printer they are not in sequence, they are randomly falling until the image of the wave is produced- hence such uncertainties/observer effects. But i dont think this is the true problem of marrying the two. Simple gravity doesnt work and is hard to be some kind of boson. QM essentially neglects time. And i think Carroll had a good explainer of another video. QM rarely deals with something massive or deal with trying to put enough particles together. So he was explaining it as emerging from entanglement added up over vast collections of particles.

[@zombienectar]

I know that time slows down at work and the clocks slow down with it so you can't tell. It is a very devious system invented by someone with a cruel streak in him. ( or her )

[@nacho74]

This is perception which plays an important role for time

[@Jamie-Russell-CME]

Get busy working and staying busy and it will fly by.

[@justdave9610]

Damn it Einstein!

[@jorgepeterbarton]

This is problem working on a starship.

[@Allesnik]

what is a moment? Answer that. A nano second, a fraction of that... where do we draw the line? We don't. There is no line, just a now. In this now we can experience memories and anticipations generated by our brains... creating a perception of time. The clock is another institution of society, built upon language as Sean mentions, but is truly an illusion.

[@maxwelldynamics7495]

+Allesnik We draw the line at Plank second.

[@ShakinJamacian]

+Maxwell Dynamics Isn't this another point that it's a conception and line drawn on moments and time? It's like saying the world doesn't come lined up and gridded, but we grid it. I think Allesnik's point is that our description, our means of figuring, is a symbolism, not the actuality. Like how money is not wealth, yet is inferred and confused for it often.

[@maxwelldynamics7495]

No, a plank second isn't just a conception. I can't see how you can think that. The very definition of plank second and length make it the minimum.

[@vidyanandbapat8032]

Allesnik Absolutely right. Time is an illusion which we measure as per the technological advancement of the concerned civilization that time.

[@jorgepeterbarton]

@@ShakinJamacian no its not arbitrary. But its not gridded or pixelated either. Light speed is the fastest possible interaction. So its a speed of time (at least for the resting reference frame). Planck time is derived from the speed of light as per planck length and all that. Its just the smallest division that would make sense due to this speed limit.

[@errolmontespizarro9956]

I am new to this discussion, hence I apologize if I repeat some ideas than other have already said. I think there is fundamental flaw in the picture the physicist portraits. The so called Newton-Laplace idea (or should I call it the Newton-Laplace myth) only works if we assume smoothness. As soon as there are singularities that claimed capacity to perfectly predict the future and know the past fails. A trivial example would be the following: a particle impacts a surface at a corner. The singularity at the corner prevents the application of whatever differential equation you are using to be continously valid after that moment. I hope I explained myself.

[@colinschabel]

Why do you assume that you can make a choice of what to have for dinner?

[@mojo5093]

do you choose what you have for dinner?

[@nikolacvetkovic4549]

It seems like there is a free will, and in this world we have no other choice than to go by as if what it seems is real. I agree it might not be the best way to look for truth, especially in this videos contexts, but it is kind of practical.

[@nikolacvetkovic4549]

@@jodypelupessy2142 In my comment I actually agreed, just said that it is not practical to look it that way most of the time.

[@jackmclaren768]

@@jodypelupessy2142 Where does logic originate? Surely free thinking beings? Analytic philosophy is an example of constant argumentation as to the modalities of logic. Free argumentation, decisions to discuss it.

[@AndrewBarbacki]

I could never get past thinking of time as a measure of the interval between events as opposed to an entity of itself as it is said to be by those in the know

[@jorgepeterbarton]

"interval" is "time". Thats tautology.

[@djayjp]

But what causes that flow to the next interval? Time.

[@lucasbarreira2957]

@@djayjp actually it is Action. Once the Universe goes completely cold, thermodynamic death, there won't be any more time , because nothing else will happen, no interactions, no mass, not even black holes, and at that point, the universe will not have any "clocks" no way to measure or "keep" time

[@djayjp]

@@lucasbarreira2957 Incorrect as there will still be actions via photons interacting. But yes I'm familiar with Penrose's hypothesis.

[@lucasbarreira2957]

@@djayjp incorrect as at that point of thermodynamical death and the unfathomably huge amount of time passed, not even photons will interact with anything

[@foetaltreborus2017]

For me the question still stands - how long a time is "now"...when does future become "now" ..then how soon does it become the past ...then how does the conscious mind stand straddled on that knife edge of incoming future & the becoming past without us going insane ?

[@MindForgedManacle]

Why on earth was this filmed in 240p?

[@thoperSought]

Mind-Forged Manacles maybe they didn't have time to convert it at a higher resolution?

[@MindForgedManacle]

ThoperSought I'm pretty sure it was filmed at a higher resolution (no camera nowadays does 240p by default). Maybe they just didn't feel like uploading it in HD because it takes longer. xD

[@Stacy55ish]

+///AMG Berg But to travel that physical distance takes time.

[@colinschabel]

It was stolen and re coded at 240

[@morgengabe1]

*Uploaded in 240p.

[@rukmaldias6762]

Trying to understand Time is like " Blind man in a dark room searching for a Black Cat ...." We cannot see .. It is only moment that we can experience.. but not see because we are blind

[@georgebernstein12]

So the cat could be neon green ??

[@fep_ptcp883]

6:35 Strange but that used to happen to me. Countless times I left the house a mess, just to found it cleaned up later on. But it wasn't entropy, it was my mom

[@shakesmctremens178]

6:20 Sean Carroll: "..the fact that entropy increases--" Interviewer: "Disorder." Me: "NOOOOO!! Not disorder!!!" >Slap! Slap! Kick! Slap!

[@ShadowsMasquerade]

Entropy is a measurement of disorder. If it increases, it means there's more disorder. How's he wrong?

[@jorgepeterbarton]

@@ShadowsMasquerade because you can often find states of very uniform things being high entropy. You can find chaotic looking things with low entropy. The definition is more like "how many times can you rearrange and have it be the same thing". Heat death is high entropy. Yet is complete immobility, lack of heat, evaporation of particles. Id say a state close to nothing happening is the opposite of disorder. Entropy is rather the force to average and level out all energies. Sometimes that produces disorder along the way. Sometimes. Too stuck on the notion of having some neatly categorised things, ending up jumbled. Like lining up colours of m+ms then having someone knock the table, so they become 'mixed up'?. That is an analogy i guess... Only goes so far.

[@continentalgin]

Artists love to play with time... Dave Brubeck, Miles Davis, Orson Welles, Stanley Kubrick, Picasso, Dali, Stravinsky, Vaslav Nijinsky, Hemingway, Shakespeare, John Lennon and George Martin, Herbert von Karajan, Leonard Bernstein, Count Basie, the list goes on and on.

[@hormigui88]

Our human experience of time (not time in cosmic terms) is a coping mechanism based on our limited sensorial perspective. It is the way our mind -in a way trapped in our bodies- makes sense of the stimulus around us. We wouldn’t be able to make sense of the physical world we live in if we didn’t take events that we perceive as previous into consideration to explain the moment we live now.

[@adrct]

When he says time might not be a fundamental entity, he means it might be like temperature. As we know, temperature is a macroscopic average measure of something more fundamental, which is the kinetic energy of microscopic particles that constitute matter. Nevertheless, temperature is real. Not only can we feel it, but also it can be measured and used to describe physical phenomena. Temperature is not an illusion. Now is the GDP, say of a country, real? It is not as "real" as my salary, but it's not an illusion either.

[@paulj6662]

Time is what stops everything from happening all at once.

[@meatpie29]

+Paul J For a photon the entire history of the universe happens all at once.

[@AsratMengesha]

+Paul J How would it do it? Is it (time) a super man!!! thanks.

[@alexojideagu]

+Asrat Mengesha anything that goes at the speed of light time travels

[@higgins007]

+meatpie29 indeed, anything that has no mass.

[@AsratMengesha]

+alex ojideagu So, photons are time travelers? thanks.

[@mattsheezy5469]

This is excellent, very well produced, and interesting.

[@KingDavid5934]

Sean Carroll makes a fantastic description of time, but for a much stunning and through conversation on the nature of time, I would always prefer to stay with Jorge Luis Borge's "History of Eternity". Highly recommended.

[@nyworker]

Can we apply the same to energy? Didn't Boltzmann reduce the illusion of heat to molecular motion? Isn't energy just a form of Physics bookkeeping?

[@ivrz]

It is always now.

[@FirestormAudio]

To experience time is to experience an increase in entropy?

[@lungflogger9]

entropy proves a form of forward time, you can't unlight a fire - it is going to burn until the fuel source is exhausted and it won't unburn.

[@Benbjamin-]

Is it so at the molecular level? What happens to the atoms that constituted the flame they are not exhausted.

[@Benbjamin-]

First law of thermodynamics.

[@lulainwonderland4244]

Fair enough. I guess what I meant about the 'point of reference' thing is that we continue believing things are 'one way' when they are really another because we follow this point of references. Like the whole wave vs particles example. For ages people thought that atoms on a quantum level behaved like particles and now they have discovered otherwise. But no worry, I do have "faith"in the scientific method, which generally has been good at keeping everyone on their toes and honest.

[@JasonWalsh-b4n]

HI, SEAN CAROL. IN U.S., IT'S ILLEGAL TO THINK.❤

[@sinebar]

My question is there a particle of time? I guess it could be called a chronoton?

[@gregbalteff1529]

I love the way sean articulates his thoughts

[@andyisdead]

He's a great speaker

[@2fast2block]

You mean he actually thinks? 1LofT states that energy can't be created or destroyed, it can't happen naturally. One aspect of the 2LofT shows that the universe is winding down, usable energy is becoming less usable. Creation had to be done supernaturally at some point.

[@djacob7]

I'm surprised they didn't mention that time passes differently at different speeds.

[@lukasthum5339]

See 2:35

[@Joshua-dc1bs]

Your not conscious. So you are having no experience of this video or this comment.

[@jamesruscheinski8602]

So while time occurs as space expands the universe; the past, present and future depend on the relative motions of space (past), light (present), and objects travelling slower (future).

[@davidbrown6340]

Time is real. Nothing can happen without it. The past is gone-its effects are in the present. It is a unique and difficult thing to understand. An infinite past baffles me, but a future that never ends is easy: we never reach the year "infinity".

[@samlau7463]

We, never be able to reach infinity, but the scar that we marked and left during our various formats of exsistance, surely lasted beyond infinity. (EVERLASTING scar).

[@lebecccomputer287]

Time is real in the sense that there is a difference between two events that are identical except for when they take place, but the past and future are all as real as the “present.” Special relativity doesn’t allow for an objective present, so this must be the case

[@davidbrown6340]

@@lebecccomputer287 I don't think Relativity leads to a single, obvious concept of time. Even if it did, I would pay attention but would not easily let it trump intuition--though I am humbled by aspects of time that evade comprehension.

[@lebecccomputer287]

@@davidbrown6340 I’ve tried to fit relativity with an A theory of time and it just doesn’t seem possible. If you can’t agree on simultaneity, then there can’t be an objective present. A theorists claim that only the present exists (or some will claim the past and the present, but not future exists). But if you do the typical thought experiment brought up of a train moving where lightning strikes both ends at the same time, there will literally be complete disagreement about what the future even is. The observer standing by watching will see the a present and future moment of the person on the train happening at the exact same time. This flatly contradicts the idea. I don’t have a problem with time dilation on an A theory of time, which is what everyone thinks of when they hear relativity. But that’s not what this is

[@odonnelly46]

@@lebecccomputer287 Exactly. According to Relativity, there is no such thing as a universal "NOW", only localized "nows". Therefore one person's past can be another person's future. So what does this say about the concept of "future"?

[@danf7568]

Rich conversation dealing with physical reality and the dynamics of the time element.

[@djayjp]

Time, I think, is the basic interaction rate between subatomic particles. Not entirely dissimilar to heat as molecular vibrations. But what causes motion in the first place? Time shouldn't flow if there is no interaction or movement. The direction of time of course is caused by entropy changing.

[@skuzzeroo]

I had a conversation one time with david bohm... and he said to me.. the true nature of time is timelessness.

[@devonfitzpatrick9201]

that is amazing.

[@Ozone280]

+phil earle I had a conversation with him tomorrow

[@endriasy3807]

+Michael Dodds I see what you did there

[@Ozone280]

Andrias When?

[@odonnelly46]

It is so fascinating to me that one person's "now" can be in someone else's past or future depending on the actual circumstances. There is no such thing as a "universal now". Only "local" nows.

[@timhallas4275]

Time is a funny thing. You can find some time, lose some time, make time and buy it, but you might run out of time anyway. Time can fly, drag, or seem to take forever, but if your patient, time will be on your side. Well I'm all out of time, which, by the way, does not really exist. It's all in your head. .. Later.

[@davidbrown6340]

lol

[@dennisgalvin2521]

Tim Hallas Thanks enjoyed that

[@SocksWithSandals]

It's always now.

[@helisoma]

@0:37 i don't think time is the most used word in the english language but would suggest instead the word f*** 😂

[@patbrennan6572]

good times ,bad times, ''you know iv'e had my share'' when a woman left home with another man and i still don't seem to care..

[@A.Lewisfilms]

This conversation is taking place in the only "time" that has ever or will ever exist, Right now. Although, your clock time brain will beg to differ A clock is a mere measuring tool, it is not "time" You can't measure infinity, that is why a clock is round. The place it started is the same place it ended.

[@Bromadlife]

There is No such thing as "Right Now".... that's a problem as well. You simply can Not pinpoint ANY moment in time as "NOW" because it doesn't exist except as a concept. By the time your brain can even think the thought of "Now", it has already passed....it just can't be pinpointed!! And the Future hasn't happened yet....and the Past is just a very fuzzy and illusory collection of images and impressions. It could be said The Past is the only one with Any basis in Reality beyond just a vague concept in our imaginations. But, really, they are ALL illusions...

[@A.Lewisfilms]

Well, I agree with your statement that "they are all illusions. It's tough to argue that point...Some things just can't be understood with words and descriptions, no matter how thoroughly you detail those words. It is when you stop talking and listen, that your able to become the moment, no formula or demonstration can genuinely describe...the utter creation of the present moments are exactly those fetal attempts at grasping and pinpointing a specific time, because you cannot pin point infinity. Once you've settled into this understanding deeply, that the present moment is all that exist...you come to see, that the world is simply looking at itself through your eyes, you've simply been born into a world that puts more importance on HOW you sell the product / rather than the product.

[@monra90]

It ends 12h after started. Not the same place. Space is infinite and you can measure a slice of it. Just like time. 5min are always 5min. A day always a day

[@ecocentrichomestead6783]

The only thing that exist is what exist in the now. in other words, what ever exist at the point we are experiencing it. There is no time travel because you can't travel to something that doesn't exists. The past and future does not exist. and time does not exist as a thing.

[@angelita5785]

David Belcher you’re so smart. Well said. I don’t know why some scientists are trying to confuse people into thinking that time is real.

[@jadeforestco]

To sum it up, time is an illusion we've created to make sense of what we don't know

[@jamesruscheinski8602]

What is relationship between time and quantum wave? Does quantum wave experience time? Sometimes almost looks that quantum wave goes backward in time.

[@mycount64]

perception of time i suspect has something to do with collapse of the probability wave.

[@bobshriner]

Time in the abstract sense is a comparative of change while time in the reality sense must incorporate the means of change from which the comparative can be derived and imposed back upon reality in the abstract. Without a clear understanding of the means for consistent, comparable, and directional change we have come to interpret that change in an unbounded abstract sense that must deny any physical means and float above in a realm of self-isolating purity.

[@jmerlo4119]

Given that our universe was able to materialize and continue to evolve because of the perfection of the events that took place soon after the Big Bang, I do not understand how a disorderly universe could start and continue to exist without becoming chaotic and auto-destroy itself in a very short time.

[@bdi_vd3677]

Paradox of survivor. The dice was rolled and so came life.

[@usaisamess8880]

listening to an extremely educated and intelligent person like this is a pleasure. I would go as far as saying the worlds best logics and scientists are the closest to God we come at this point in time. its like watching Messi play soccer, Carlsen play chess or Mozart create music. Just wonderfull

[@ramaraksha01]

Yes that is what Hinduism says that we are, as children of God, supposed to walk in God's footsteps, the Saviors not the Saved, those who aspire, reach for the hand of God But the problem is that what stands in the way - Pain & suffering And so those who say no more pain & suffering are rejecting God

[@alexsnowberg2181]

I once knew a physicist that was working on the idea that time is our awareness of the expansion of space. He passed away before publishing anything. I didn't understand his explanations, but I remember him saying that Einsteins space time is incorrect. That in fact it's "expanding space time". Space and time are different sides of the same thing because space is expanding and creates "quantum holes" which must be filled. The holes being filled created by space expanding is what we feel as time because these "quantum holes" allow us to go from point A to point B in space, or some such craziness that I don't understand. I also remember him saying something about if space didn't expand we could not travel through it. It would be like a solid and there could be no motion, energy or time.

[@nacho74]

How does he look like? This theory sounds great but there is still a time needed for any expansion to happen

[@shivamkashyap5968]

The idea of time is much more messy and mysterious sir Caroll have his own point of view and it's really awesome ❤️

[@tedgrant2]

We can see stars, using our instruments, that may not exist anymore. The reason is that light has a finite velocity. Yet we can see them now, in the present. So are they part of "our" universe ?

[@nightjarflying]

Interviewer's opening statement is provocative although there's some cosmologists who hold that view. However neither person on the video says "time can not exist"! The big question is... is time a fundamental or emergent property? What if time & space [or spacetime] are products that emerge from some deeper physics? In Carroll's opinion the property of *time* is fundamental & will be a property of any proposed deeper physical theory that is developed. Lee Smolin & many others agree with him.

[@TheBruces56]

"Time" is different for all conscious observers, relative to their speed or proximity to gravitational fields. It is probably different for each cell in their body.

[@jamesruscheinski8602]

If time like an escalator (previous comments), the steps going down are the future, the escalator itself is the present, and the entire escalator being moved upward is the past.

[@theodoreanderson6670]

What exactly is prof Carroll referring to when he talks about Newtonian physics creating a problem with the past and future?

[@hagoromootsutsuke6561]

I don't think that time flows. I believe that the past interacts with the future and that dissonance creates something like a present. - Where you are born and die instantly - If you have you're favorite meal tommorow, you will feel good today.

[@jessesipprell]

Hagoromo Otsutsuke I'm not sure how the past could "interact" with the future without some sort of causality. But that rather begs the question, because what Dr Carroll is saying is that causality and causal chains are really just another way of talking about thermodynamics (and specifically the thermodynamic descriptive rules of our local universe). If the rules were to change "tomorrow" such that entropy tended to _decrease_ rather than increase in a closed system and the total entropy of interacting systems could stay the same or decrease but never increase then causality would be reversed -- causal chains of linked events would invert. Because causation of some form is a fundamental part of our psychological experience of time passing it's difficult to see how this too would not be reversed. Dr. Carroll alluded to something else which is quite pertinent to the entire discussion, but it sounds like he didn't really have time to go into detail. When we look at the universe in a very fundamental low-level fashion it appears that causation isn't really a foundational part of it, or rather that the _direction_ of causation (events are preceded by antecedent causative events) isn't foundational. This can be demonstrated by a very simple real-world experiment, one that runs counter to most people's intuition. If you take a normal billiards/pool table, two billiard/pool balls labeled "A" and "B" and set "A" in linear motion (with no spin) so that it strikes "B" with enough force to move it, there will be the intuitive experience that you have created a simple causal chain. (The motion of A caused it to strike B,and the resulting momentum transfer led to B's motion and thus the final configuration of the table). Suppose now that you were to use a video recorder mounted above the table, positioned so that it could *only* see the surface of the table and the interaction of the balls (no hands visible etc). You then watch two independent copies of this video, one where the video is played back exactly as it was recorded and the other played back at normal speed but completely in reverse. What you will discover is that if you show this to someone who didn't witness the experiment being performed, they *cannot* tell which video is reversed and which isn't. Both will look like causal chain of events, one where A was in motion first and struck B and one where B was in motion first and struck A. What this means is that cause/effect are symmetric at the most basic simplest foundational level of the universe. Cause and effect are only distinguishable by way of unrelated or indirectly related ancillary events (as long as the symmetry holds), the only thing that matters is that one must necessarily, yet arbitrarily, be antecedent to the other. Now, this particular symmetry breaks as soon as you go beyond these most basic foundations. The symmetry breaking also shows up in the macro experiment; if you spin ball "A" while putting it in motion or add a ball labeled "C" into the mix such that it can be struck by either of the other two balls, it will be completely obvious which video is reversed and which is not.

[@faiselbutt2944]

Nonsense.

[@kevinking7414]

Isn’t time real and go in a direction because of entropy? *please answer this is a sincere question*

[@NFLDraft_Luigi]

we are all time seers. its what makes us great, yet its the single most under-appreciated and misunderstood part of being alive, truly, it bums me out. stop being dumb to it, fellows. this should be a big party! dont let em tell you anything different! burn the book! have more fun! appreciate your power!

[@leighfoulkes7297]

Could it simply be that our time is so minute that it registers as zero (the number is so small that you round it to zero), compared to the infinite time of the universe and therefore, we do not exist?

[@davidwalker5054]

if the universe did not have time as a safety device. Everything thats happend.in the past and everything that is going to happen in the future will happen instantly it would be chaos

[@whatshisname3304]

it would mean nothing happened... causality would nt be possible or it be like a jam of cause/effect.

[@Hythloday71]

Time is simply the acknowledgement that there is an update of configurations. And in this sense there is both the concept of ordinality and absolute time. But, just like so many modern day concepts, the absolute nature is not accessible to us. (I refer to uncertainty, entanglement etc. This is just an unfortunate reality that forever confines us to philosophical guessing beyond certain points but is a total logically reasoned necessity based on any reasonable assumptions and definitions IMO.)

[@jamesruscheinski8602]

As space expand through quantum field, time is moving from the past at edge of umiverse toward the future in center of universe. By some operation, as universe expand the earliest part of universe gets taken out to the edge, so that as space expand outward, time moves inward towards center of universe.

[@milesfurnell]

In the universe there is only what is happening, which takes place as a consequence of what has happened. We can predict what will probably happen based on those two but it doesn't exist until it is happening. Time is simply an arbitrary metric that we apply to the relationship between cause, effect and probability. Even if energy flows could be reversed we would still perceive things as what happened, what's happening and what will probably happen.

[@MA1980c]

Referencing entropy as a process leading to X, a start, implies time, and is contradictory to the model of non fundamental time

[@123unknownsoldier126]

But DO we have a choice of what we’ll eat for dinner tomorrow?

[@Kerrsartisticgifts]

I wonder, could time be explained if it were the result of the expansion of space and if gravity affects/slows the expansion? This would explain the arrow of time and the fact that time is relative.

[@odonnelly46]

Except that the expansion is NOT slowing down. It is accelerating with time.

[@Kerrsartisticgifts]

@odonegan4865 , I didn't mean that the overall expansion was slowing down. It's a common fact that it's generally speeding up. I meant that gravity slows it down locally, explaining relativity to the position (in a local gravity well or the equivalent velocity or acceleration) of the observer. If time is not a separate dimension but the expansion rate of the 3 spacial dimensions "and " gravity slows the expansion "locally" then time would pass slower around Jupiter than it does around the Earth and that's Relativity. If time is the expansion rate then that would explain why the arrow of time only goes in one direction that we can observe. I think it would reverse within the event horizon as Space contracts in a black hole. If it does reverse within a black hole, then maybe black holes lead to white holes in the past?

[@kwecsk9132]

At 5:42, that's what most people mean when they say history repeats itself. Essentially past = present = Future. We are just in cycle without a beginning and without an end.

[@DerivedEnergy]

''According to this theory (which is accepted by most physicists) the universe is an unchanging block of spacetime'' No. It's a very speculative theory and multiple cosmological theories are being hotly contested right now. A good scientist does not 'accept' a theory until he has sufficient empirical evidence for doing so.

[@jamesruscheinski8602]

does the feeling of flow, arrow and absoluteness of time come from quantum mechanics in the brain / mind?

[@yief3194]

Is it possible for aliens (in our universe) to be experiencing time backwards from us? Not sure if that even makes sense, just posting to hear thoughts.

[@Muongoing.97c]

It’s been nearly a year but no one has responded yet so I figured I’d take a stab at it. Let me first start by saying, I don’t know. “Is it possible for X” has the interval of 0 < P(X)

[@GiordanoBrunoful]

fascinatingly confusing......damn.....the more i understand, the more i'm confused......i guess i didn't understand anything at all........feels so good when you're confused......love it

[@martinet1985]

beef it up boy!

[@jamesruscheinski8602]

Is there a time that moves the entire universe, as well as time that moves in the universe?

[@wafferz]

Got it! John Mulaney! That's who he sounds like.

[@BaldingEagle51]

Good interview, hearing this explanation makes the statement at 7:25 really stand out. Every single Physicist that has been wrong through history has known the laws of Physics perfectly. While the statement is a tautology and therefore true, when the problem of the day has been solved, the outcome has always been that the laws of Physics have changed, so that the tautology makes no sense.

[@Eldooodarino]

The laws of physics don't always change. That is nonsense. Occasionally they change as phenomena are discovered that can't be explained by the laws as they are currently known.

[@BaldingEagle51]

@@Eldooodarino If you understand the video up to the point I mention, you will know where my comment comes from.

[@Eldooodarino]

After a 40 year career in physics I don't think I've known a single physicist make the claim that we "know the laws of physics perfectly." From the time Einstein wrote his paper on light quanta, which incidentally explained the photoelectric effect, it took 18 years before the physics community finally accepted light quanta with the discovery of Compton scattering. Who "knew the laws of physics perfectly" during those 18 years. Nearly all thought Einstein was wrong and yes, I know he was awarded the 1921 Nobel prize (in 1922) for his explanation of the photo electric effect but there wasn't a mention of light quanta in the award. They HAD to give him a prize for something and since Millikan had shown that the kinetic energy of electrons emitted in the photo electric effect behaved as Einstein predicted they gave it to him for explaining the effect in spite of the fact that they couldn't bring themselves to mention light quanta in the award. A few weeks later Nils Bohr received the 1922 Nobel prize and devoted some of his acceptance speech to trashing Einstein's light quanta theory. After Compton scattering was discovered which cannot be explained in terms of classical electrodynamics the flood gates were opened and then it took about 7 years to work out the quantum theory that we use today. Your version of the history of physics simply doesn't jibe with the history of physics.

[@BaldingEagle51]

@@Eldooodarino Again, this is about understanding the conversation up until the point I mention. As I read your protest, you seem to confuse what I write with "at any point in time, Physicists have understood all of Physics perfectly" which is quite obviously false, since new laws have been needed, theorized and tested through most of Man's modern past.

[@Eldooodarino]

@@BaldingEagle51 I understand Carroll fine. Some physicists are hoping to develop a theory in which time is an "emergent property" of the theory but Carroll expects time to remain fundamental in whatever theory we end up with. I'm agnostic on that particular issue. I'm quite familiar with the issues of past, future, and irreversibility in physics. I've read Paul Davies Physics of Time Asymmetry and various papers published in the physics literature on it the issue which is fundamentally that the second law is irreversible while the microscopic laws of physics are reversible. Usually this seeming contradiction is ascribed to "coarse graining". Einstein once thought he'd derived the 2nd law from "first principles" but then discovered he'd made an assumption that was equivalent to the second law, namely that more likely probability distributions follow from less likely ones. There's no guarantee of that. Understanding you is a different thing entirely. I have no idea what you think this sentence is supposed to convey: "Every single Physicist that has been wrong through history has known the laws of Physics perfectly. " I agree with you that your sentence "makes no sense."

[@ThexBorg]

Time; is influenced by gravity, which when there is a higher mass and density it influences time more the higher density of mass.

[@peterburandt4586]

Reading the comments here reminded me of the film "My Dinner with Andre" by Louis Malle.

[@Cryptokingbali]

Time is only 'real' because of our current state of mind. With meditation and giving up all material connections one can exist forever in the ether. A dream within a dream. The dreaming is real and a dream

[@jamesruscheinski8602]

Does time happen when space expand through quantum field?

[@jamesruscheinski8602]

Is it possible that time in quantum mechanics moves from future to present to past, while person senses time spatially from past to present to future (time and space moving in opposite directions)?

[@lulainwonderland4244]

Hmm. Okay, I see what you mean. An organism decaying is therefore not something that is a continual process (like a layer of cake being 'added on) but a whole cake that is already there (just in a different dimension). That helped to understand the 'perspective' but not why they think it happens this way but that is another bizarre idea for another day! *eyes popping*

[@mattsheezy5469]

Sir Roger Penrose seems to think that consciousness can be explained within the parameters of quantum field theory. I’m curious to know why Sean thinks that Penrose is wrong, & how someone who is considered so brilliant could be so mistaken.

[@jamesruscheinski8602]

Does entropy affect human behavior?

[@iancopsey875]

Time is what we need on the earth. On the spiritual plane, there is no time.

[@nyworker]

6:00 "we can remember yesterday but we can't remember tomorrow"....ummmm....we can predict tomorrow but we can't predict yesterday... Can I just say it all has to do with not fully understanding our brain mechanisms of memory and prediction? Specifically that they are so complex in terms of actual integration. Maybe if we straightened that out, the physics would be simpler?

[@loveflowers39]

Time is our way to quantify duration and change of what we experience in our reality..

[@halilkann]

loveflowers39 And what's duration? xD

[@halilkann]

- Progression is a quite clear word at first, but it still doesn't "paint" the time on the way that a "regular" human could think of it. - An emergent phenomenon? - that's quite hardly understandable concept and the definition doesn't say much. :) I believe that a human will easier get the essence of the time, than a words to describe it. :D That's why your sentences are probably understandable to people who already know a lot about the physics, and not to me. :) Your words obviously can't make me understand things. It must be my own praxis inside of physic as a science.

[@halilkann]

Do it.

[@nacho74]

Quantifying duration doesn't explain the motion. A change already requires time to happen. Can there happen a change without given time? No An experience also requires time since one can't have one without it

[@nacho74]

***** Your answer is also not satisfying although the implications are good. A progression and an emergent phenomenon does also require time. Without any given time, nothing can progress nor emerge. So, one can't define time with words which are already defined as temporal properties, to say so

[@jamesruscheinski8602]

Does entropy move time from past to future in universe, or is part of a description of time in universe?

[@bruceruttan60]

Time is a measure of motion, unless you need to screw with it to 'prove' something really weird.

[@dynamic9016]

Very interesting information.

[@syria55]

Well before talking about my words narrowly defined, could u please explain more about what u mean by saying that the wave function is a metaphysical menifestation of using dualistic logics? I want u to define metaphysical and how did u come about using this words?

[@alphabeets]

Time is just a concept that we humans have created. It is a philosophy. Nothing more.

[@ecocentrichomestead6783]

Time is an interpretation of a sequence of events. Before, during, after. If you base time on a repeating cycle, you can organize other things around that cycle far into the future and speak of past events relative to that cycle. Currently, we relate our events to the rotation of the earth on it's axis (days) and it's revolution around the sun (years). We have split each cycle into subsections to make it easier to relay information that has a shorter duration than a single cycle or starts part way through a cycle. It's easier to use "one hour" instead of "one twenty fourth of a day". But time itself, does not exist. The only thing that exist is the movement of physical objects. And we are making sense of that movement by invoking the idea of time.

[@smokinjoe4709]

Ageing would disagree with you....

[@dennisgalvin2521]

@Eco Very true,also it's the earths rotation on it's axis that gives the impression of times passing,but it's just individual days passing. The earths rotation creates the illusion of the sun rotating around the earth in clockwise fashion just like the hour hand of a clock. Times passing is also an illusion created by the earths rotations just like sunrise and sunset. Basically we believe time to be real because we live on a clock.

[@dennisgalvin2521]

Why so? aging is a result of telomere deterioration.

[@macsnafu]

I don't get why time isn't fundamental. Sean Carroll himself points out that our universe works the way it is because of time, and would be radically different (and devoid of life) if it didn't have time. Without time, there would be no causal relationships. Without time, the universe would not make sense, or at least, would make a very different type of sense.

[@davidbrown6340]

YES