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Carlo Rovelli on the ‘greatest remaining mystery’: The nature of time
- pmoriarty 8y agoNot to nitpick, but I'm not sure the nature of time is so indisputably the greatest remaining mystery. The nature of consciousness, life, and death can all certainly give it a run for its money. Incidentally, would anyone happen to have a direct link to a version of this article that could be read without enabling javascript?
- imglorp 8y agoAlso the origin of the universe, why it's accelerating its expansion, how are gravity and quantum phenomena reconciled and how do they work.... I'd say it's a great time to be alive and there's no shortage of important questions!
- everdev 8y ago"Nature of existence" probably encapsulates all of those ideas including time as time seems to be required for a creation/destruction type event.
- simondedalus 8y agonature of consciousness is the biggest one IMO, precisely because it doesn't appear to be captured by "nature of existence." we have good physical/mathematical models on hand re: causation, such that we can at least start hypothesizing about what change is, where the universe came from, what if anything differentiates life from other motion, etc. but consciousness is so categorically different that we can't even start. "well, brains are made up of cells and further of particles, and electricity works this way and here's some results from information theory and [UTTER MAGICAL WALL / ABYSSAL GAP] then there's the subjective experience of consciousness and will. and damnit we don't have anything like a logical or explanatory connection between these two sides, but for 'well, if i destroy 'someone else's' (??? what's this possessive in our fundamental terms???) body in the right way, it stops acting as if it's conscious like me, and also my own consciousness (which i can't describe with any specificity) changes when i do weird physical things involving drugs, injury, nutrition, um... and attitudes seem to matter, and there's definitely a subconscious, i guess, and...'..."
- perl4ever 8y agoIf you accept that other people are conscious like yourself, it seems like you have accepted the physical origin of consciousness. If you don't accept that the subjective experience of consciousness is just a product of physical events, then how do you avoid viewing yourself as the only conscious entity? You can be a solipsist or not, but you can't have it both ways. Experiencing thoughts from outside yourself is a common experience, but it's generally considered a delusion.
- simondedalus 8y agothere's a gulf as big as the ocean between acceptance and explanation. we have good reason to assume that consciousness (whatever it is) depends on the physical. great, but what is it?
- perl4ever 8y agoI wasn't taking sides on whether it's physical or not, so I wouldn't particularly agree with your statement. I'm only trying to say that if you don't accept that consciousness is physical, you aren't accepting the symmetry between you and other minds, and can't reason from the assumption they have the same experience. Once you contradict the known fact that you experience your own thoughts and not others, you descend into incoherence. It seems to me kind of like the issues people have with quantum weirdness. People are accustomed to assuming they know things for the sake of argument, but assuming you know the unknowable can sabotage your reasoning.
- beesmum 8y agoWhile I think it's an interesting argument, I don't agree that accepting that some other being than me can be conscious leads to having to accept the physical origin of consciousness a priori. If you look at Buddhism or any esoteric system, they essentially posit that consciousness is a unified field from which everything manifests, like light refracted through an (infinitely) complex array of lens. The spots of light where the light terminates look separate, but if you look at where the source of the light enters the lens, it all comes from a single source. The experience of having a separate consciousness and a body or mind or thoughts that I identify as me or an I that is not you or that car or that tree is essentially just an illusion because I don't have the awareness to be conscious of that unity. Just because something appears to be separate from one perspective doesn't mean that it's separate in reality, it's just that I experience it as separate due to my limited perspective. Consciousness is an experiential vehicle by nature. It doesn't slot into the scientific method all that well no matter how we try to cram it in.
- 8bitsrule 8y agoTime is a convenient measure of relative energy. (Just as the length of a king's ulna once defined distance.) IMO, 'creation/destruction' is another convenient idea, invented because our minds are boggled by 'eternity'.
- jfaucett 8y agoYes. For me the greatest remaining mysteries are more in this order. 1. Nature of Life (we are still nowhere near understanding how it arose or how living organisms work in all their intricate detail). 2. Nature of Consciousness - what is consciousness, how can living matter instantiate it, how can we quantify it, etc? 3. Origin of the Universe 4. Why do we seem so alone in the Universe? 5. Resolving Quantum Mechanics / Gravity 6. Understanding Time
- whatshisface 8y agoI would bump the origin of the universe to the top, because no matter what universe-generating physics you come up with I can always ask, "but what set things up to work that way?" I'd also put consciousness up there, because it's fundamentally distinct from measurable things. Consciousness and the origin of the universe get place 0, and the others all get place 1 because they're solvable but we don't know in which order.
- pmoriarty 8y ago"I would bump the origin of the universe to the top, because no matter what universe-generating physics you come up with I can always ask, "but what set things up to work that way?"" Except that it might not be possible to get outside of consciousness to have any testable way of explaining what set it up to be that way. It seems that we are hard-limited by our consciousness, and have no way of going outside of it to peek at "the universe" beyond.
- redial 8y ago> I'd also put consciousness up there, because it's fundamentally distinct from measurable things. No one knows that it is not measurable. Is love measurable? is hunger? happiness? they seem to be as measurable as consciousness, that is to say we can at least measure them in binary as either present or not.
- andrepd 8y agoHow do you know everyone else is not a "p-zombie", indistinguishable in any external way from a human such as yourself, but devoid of internal "consciousness"/"subjective experience". Even the mere logical possibility of p-zombies indicates that consciousness is unmeasurable.
- trevyn 8y agoConsciousness: Thomas Metzinger’s “The Ego Tunnel” Life and death: Molecular biology
- andrepd 8y agoThe way you curtly replied makes you think that the question is settled, perhaps even trivial, when in reality regarding consciousness that is but one person's thought on an issue where nobody can claim to have an understanding, let alone an answer, and regarding molecular biology there is still much, much to learn.
- make3 8y agohow is death misunderstood?
- perl4ever 8y agoI don't know, but here's some food for thought: https://en.wikipedia.org/wiki/Quantum_suicide_and_immortality https://en.wikipedia.org/wiki/Quantum_suicide_and_immortalit...
- codethief 8y agoThis is hardly casting doubt on the nature of (human) death. This is purely a question about quantum mechanics, I'd say. On a side note, I fail to see how the experimenter is supposed to survive with probability 1 in Everett's many-worlds interpretation and thus be able to distinguish the latter from the Copenhagen interpretation. Yes, there will be one world where he survives but in the "vast majority" of worlds he will be dead. (Disregarding for a second that counting how often the world bifurcates in the many-worlds interpretation is a somewhat delicate issue.) So in terms of probabilities, he will still die with absolute certainty as the experiment gets repeated infinitely many times.
- perl4ever 8y agoThe idea is that everybody else dies with certainty, from your observation point, but you yourself can't, because the denominator of the probability fraction consists only of those futures where you exist. It happens to be a vivid idea to me, because a long time ago I read a short story that was more fantasy/horror than science fiction, but resembled it a little in spirit. It was about a kid in a small town who discovered that the grave digger for the town seemed to know ahead of time who would die, and dug the graves in advance. The kid thought this was just mildly interesting as long as it was just elderly people he didn't care about, until one day his parents were in a car accident and because one grave was ready, he knew one was going to die. He killed the grave digger and buried him in the open grave instead, and from then on, people stopped dying. Which turned out to not be a blessing.
- perl4ever 8y agoI'm not sure I can conceive of the nature of any of those things being separable from the others, so I wouldn't try to compare them.
- mikec3010 8y agoI dont think time is any more mysterious a concept than space. Asking "what is time" is just as enigmatic as "why are there 3 dimensions and not 1,2,4 or many more?" How can you have a thing that is "left" or "up" of another thing? How come "all the things" aren't in the same place?
- howard941 8y agoC-SPAN videotaped Covelli speaking about his new book at a bookstore. About an hour long: https://www.c-span.org/video/?445419-2/the-order-time https://www.c-span.org/video/?445419-2/the-order-time
- crb002 8y agoPlanck's constant, speed of light travel when you chain across space which Planck himself should have understood if he thought about transmissions of information in series. Curves when gravity pushes/pulls light from straight paths. What questions are there?
- andrepd 8y agoYour comment is gibberish (I've read it 3 times and can't make head nor tails, but maybe I'm missing something).
- ballenf 8y agoRoyal Institute presentation that I really enjoyed. Has some visual aspects, but can be mostly listened to while driving: The Physics and Philosophy of Time - with Carlo Rovelli > From Boltzmann to quantum theory, from Einstein to loop quantum gravity, our understanding of time has been undergoing radical transformations. Carlo Rovelli brings together physics, philosophy and art to unravel the mystery of time. https://youtu.be/-6rWqJhDv7M https://youtu.be/-6rWqJhDv7M Posted 13 June 2018, recorded 30 April 2018.
- badrabbit 8y agoI think I'm a simpleton because I could never imagine time being it's own thing. I see time as simply the amount of change in reality we can perceptually sample. Much like how an object in motion will continue in it's motion until it meets resistance,reality in my opinion is in continuous motion that has yet to meet resistance. Time (imo)is our measure of this change divided by our ability to sample it(where this ability could be second,minute,etc...) Again,that's my opinion as a layman. I've always wondered why time was the focus, when I at least have been more curious about universal change. Why is everything in motion? and how is everything universally connected to where it changes at the same rate? Maybe there's already plenty of work on this and I'm being ignorant(apologies if so).
- gowld 8y agoSounds good. Next, please define "change", and explain why or how "change" exists and is detectable by humans. That's what Rovelli is investigating/theorizing about.
- badrabbit 8y agoYes but they are investigating our relative perception of the change. It's like studying astronomy without considering the fact that the stars we perceive in the sky is just our perception of how they looked like in the past. We distinguish how things are now from what we can perceive by measuring light and EMR. Why can't we at least consider the possibility that our perception of change might be different from the actual nature and attributes of this change?
- vermilingua 8y agoYou don’t need to consider that what you see in the sky is “in the past”. The light that’s reaching us has been travelling at c, the universal speed limit. Since we cannot possibly have known about that information sooner, what we see in the sky is for all intents and purposes, “the present”. Additionally, the hidden variables of the change are exactly what they’re talking about when people ask the question “what is time?”.
- 8y ago
- dyukqu 8y agoSome tangential thoughts: even though I like these popular science (physics, to be precise) books, I have hard times to imagine their writers as a real scientists. Tyson, Greene, Carroll, Kaku, Rovelli... So many writers author so many books about these hey-look!-so-fascinating! things. It looks like a bandwagon and more and more scientists (yes, physicists especially) are getting on it - like they don't have any important research to do, like they are so hopeless and desperate about the current state of physics and they stopped caring about it and found a proxy to monetize their knowledge. But hey, that's not a secret anymore - everyone knows about the crisis, from the Queen of England to the hounds of hell. Sabine Hossenfelder is a legend for me. A few years back, when I was taking a Physics101 class, even the lecturer almost begged for help after the last lecture at the end of the semester: "my fellow students, please, please, consider (to continue your career in the field of) physics. Physics is stuck. It needs new ideas, new theories, new minds. Please consider this." I was stunned. That was some real thing. I guess the fast advancement of technology in the late ~100 years made even the most brilliant minds (relatively) lazy. They gradually stopped thinking, beating their brains out year after year and here we are. No serious discovery after the quantum theory. String theory? Yeah, gazillions of dimensions - good luck with that. Higgs boson, Gravitational waves? Come on, nothing revolutionary - we're still waiting for the revolution to emerge from (upgraded!) LHC. For me, they are cleverly and beautifully marketed (minor) findings. (Maybe some of you have heard of, some (if not many) of the top universities have teams working hard doing all the "scientific-marketing" for the Nobel Prize - it's a precious prestige win in this popular world we live in). Minds get eroded by technology by heavily relying on it. And it's getting worse and worse by the distraction caused by all the digital "life" surrounding us, pulling and tightening its ropes every day. I imagine a true scientist as a monk. S/he doesn't think about writing a pop-sci book, appearing on TV and s/he got a distantiation even for interviews about her/his latest important research/discovery. "Monks" are needed more than ever for science nowadays. Those were my humble 2 cents.
- blueprint 8y agoIt's funny because as much as you recognize this, the people you describe as being needed are treated terribly not only by the establishment but those who think they are outside of it. Perhaps that explains this state.
- GnarfGnarf 8y agoTime does not exist. It is an abstraction based on the movement of matter. We use time to compare the relative motions of things. Every instrument we use to "measure" time involves movement: pendulum, sandglass, rotation of Earth, translation of Earth around the Sun, vibration of atoms, etc.
- fela 8y agoDon't you need time to even define movement? Movement is a change of the position with respect to time. So without time you can't have movement. But obviously you are right that the two concepts are strictly related, that doesn't mean time doesn't "exist" (however you define "exist").
- idunnooo 8y agoForgive me for sounding rhetorical in this question, but I'm genuinely wondering.. Isn't saying "time doesn't exist" akin to saying "human thoughts don't exist"?
- mgamache 8y agoParadoxically, thought (human or not) is the only thing we might be certain exists. https://www.the-philosophy.com/solipsism-definition https://www.the-philosophy.com/solipsism-definition
- hansen 8y agoAll our accepted model of nature assume that in some sense time exists. But in general relativity it doesn’t make much sense to speak of a single event. In the same way it doesn’t make much sense to speak of a single point in the euclidean plane (you can only localize one point relative to another one). So some people (like Rovelli) think one should try to formulate relativity only in terms relations of events. This might be relevant in a more fundamental theory of spacetime but on a classical level it’s irrelevant. You can measure the geometry of spacetime in our solar system w/o disturbing it. The gravitational field of e.g. some satellite is negligible to the gravitational field of planets and the sun.
- FrozenVoid 8y agoTime could be composed of tiny frames(quanta) of time. https://en.wikipedia.org/wiki/Chronon https://en.wikipedia.org/wiki/Chronon https://archive.org/details/arxiv-hep-th0106273 https://archive.org/details/arxiv-hep-th0106273
- dschuetz 8y agoAnd what do those "time quanta" represent? "Time of light traversing the radius of an electron", really? Isn't that just another measurement device based on light quanta and distance?
- backpropaganda 8y agoNo. That "time quanta" represents the smallest value Δ such that it doesn't make sense to take about events which happened between t and t+Δ. Δ may not be a constant though like Planck's constant.
- dschuetz 8y agoThe shortest distance between two events in space and time, when there are time quanta, then there must be space quanta as well.
- backpropaganda 8y agoWhat do you mean? We do already have space quanta: Planck Length.
- dschuetz 8y agoAh, well, I heard Planck Time also already exists. What's the point then re-inventing time quanta when they already are defined?
- Maro 8y agoDisclaimer: I'm a physicist who didn't finish the Phd and went to work in the tech field instead. I wish physicists would stop writing these bullshitty popular science books. A lot of the books are popularizing unverified / unverifiable things like String Theory or Multiverse or Arrow of Time. And when they're talking about more plain things like Special Relativity, then I still cringe, because it's not something that's worth explaining to lay people: there is no situation in which some high-level bullshitty understanding of GR or SR or QM will be helpful or relevant in life, at best it will confuse you. It is a good and necessary thing to tell students about this, so some of them become physicists, but you don't need popular science books for that, it should happen in schools, for free. If you're going to speak about Physics to lay people, at least do it it in a way that's relevant to them, eg. look at how Feynman taught Physics. Explain how a boomerang works, or how thermodynamics relates to photosynthesis.
- boffinism 8y ago> it's not something that's worth explaining to lay people Lay person here. I'd just like you to know that we experience curiosity too. Also, having read some Rovelli, I should point out that he's pretty good at highlighting when and how he's simplifying, and flagging up when he strays beyond the scientific consensus into the unverified.
- jpmoral 8y ago> there is no situation in which some high-level bullshitty understanding of GR or SR or QM will be helpful or relevant in life, at best it will confuse you. If I only learned and experienced things that would be 'helpful' or 'relevant' it would be a very dull life.
- hansen 8y agoYeah, science isn’t about being useful and relevant in day to day life. It’s an important part of human culture and scientist should at least try to communicate their findings to general public (which is paying for it!). I partially agree with the first comment that it isn’t really helpful to popularize highly speculative – and thus probably false – ideas. But well established but still “weird” discoveries like GR & QM are interesting on their own and have huge implications on our understanding of nature. You don’t need a science degree to be fascinated by black holes, the big bang and quantum weirdness.
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