7 ms·

The Grand Illusion: Does time have a future?

61 points by benbreen 12y ago

drostie 12y ago
The philosophy of time is one of the remaining bulwarks of a philosophical position called 'dualism', which holds that minds are completely separate from our bodies: if you view us as being big ropes of particle-worldlines in a 4-dimensional fixed universe, you are basically stuck with describing us as "souls" who have latched onto this rope and are traveling along it, living the experience even though the future is as set in stone as the past. It makes relativity really easy to understand, but it makes entropy comparably harder (since the premise of entropy is that our uncertainties multiply due to particle collisions until things end up in more and more uncertain states). It almost sounds like there's no free will in this perspective, but that's not quite true. Instead you get a model of free will which is a lot like you see in the movie The Matrix: "Because you didn't come here to make the choice, you've already made it. You're here to try to understand why you made it." Relativity does not necessarily compel this. It is true, the relativistic "present" is a space between two light cones, and not just one plane. But that's not necessarily a huge obstacle: we can just pretend that there is one plane which is the "true present" and accept that the laws of physics make it impossible to know if we're truly right about which it is. As long as one of the planes is the true present you can lift up the Newtonian way of looking at time to the special-relativistic whole. It turns out that black holes aren't really so interesting as this article claims, because there is a 'co-moving' metric which falls into the black hole's event horizon in a finite time. What happens with a black hole is, you see someone slow down more and more to a standstill as they approach the event horizon, appearing to "merge in" with that surface, redshifting into the quantum noise of the Hawking radiation there. But from their perspective, you're just seeing their "last moment in this universe"; they'll keep going on past that horizon. But general relativity is still a problem. It describes the causal fabric of the universe as warped by the energies that inhabit each part of that fabric, and that makes it really hard to deal with time. Some of the interesting stuff here comes either from (a) alternative descriptions of relativity (like spinors/twistors, where you describe the entire world-line of a particle as a point), or (b) quantum mechanics (where you can do multiple-universe-splitting). The combination of relativity and quantum mechanics, for example, seems to give us the Wheeler-de Witt equation, which time famously "falls out" of (it plays no final role in the equation). Some physicists, notably Julian Barbour, think that this means we've got to fixate on a static universe. I'm totally undecided on this but I find it fascinating.
- lg 12y ago
  I don't think the frozen block view of time necessitates a belief in anything traveling along a world line (how would you express the speed at which it travels?) At any given point on your world line your brain is in some state and your 'mind'/conscious experience at that instant is what it's like to be that state.
  - drostie 12y ago
    The "speed" of consciousness would just be in terms of the subjective rate of experience. But yes, that's a significant problem with appealing to this sort of attitude outside of this 4D world (you have to invent some notion of time which applies to souls but not matter). It is true that you can "step back" from the world-line and insist that every part of it is conscious, but that takes a really radical position on our own conscious experience of the progression of time, one that's actually distinctively Buddhist, if you can believe it. (There's a lot of Buddhist speculation about how the mind is a series of "aggregates" rather than one temporal whole; the idea is that you are no more identifiable with the you-of-twenty-seconds-ago than a candle's flame as it has exhausted a new quantity of vaporized oil: in a metaphorical sense we say that both "are the same" but we don't really mean much by it. In general though, saying that "the whole worldline is conscious" abdicates our notion completely that time progresses, and instead says it's all illusory (we have a local sense of progression even though nothing progresses). I think that the reason that this is unpopular is simply because if such an illusion exists, it has an interesting asymmetry with other illusions: you can't actually shake it. (It has some other problems, like: it's hard to see why natural selection would assemble those world-lines into something which have these feelings, given that they don't seem to do anything -- and of course natural selection becomes just a metaphor to describe a pattern in how the lines are structured, rather than a force which changes the world, so it's hard even to phrase the question much less answer it.)
- Lambdanaut 12y ago
  I have almost no experience with philosophy like this, but somehow have come to a very non-dualistic worldview of my own through a lot of thinking and writing in my personal journal. The whole "universe is a static 4D object" idea. I've never heard of anyone else talk about it before except myself. Are there any books that you can recommend that delve into the philosophy behind this?
inzax 12y ago
As shown on https://www.facebook.com/pages/Hacker-News/1558365107716690 https://www.facebook.com/pages/Hacker-News/1558365107716690
lisper 12y ago
http://blog.rongarret.info/2014/10/parallel-universes-and-arrow-of-time.html http://blog.rongarret.info/2014/10/parallel-universes-and-ar...
wuliwong 12y ago
I take umbrage with this part: "A past that can be revisited has not really passed. So, Gödel concluded, time does not exist." This is a very silly conclusion. My assumption is that the silliness is attributed more to the author of this article than to Gödel himself. Our intuitive concept of time from our existence at speeds very slow compared with the speed of light and at masses which are very small when compared to those necessary to bend space-time is not necessarily applicable to time in all regions of this speed-mass phase space. Particularly the regions where the speed is close to the speed of light and the mass is very large. There's just no logical path from the initial observation to the conclusion that time doesn't exist.
- scobar 12y ago
  I admit I'm well below the mental capacity to confidently state something as bold as "time does not exist", but I'd like to offer my thoughts. When thinking about Schrödinger's cat, [1] I imagined that the cat remained dead (and in every other possible state) even after the observer had confirmed the cat was alive. Every unobserved state did not collapse, but became inaccessible by means currently understood. Those states could still be observed by the same or another observer from a different perspective (i.e. revisiting the event). We just have to figure out how. [1] http://en.wikipedia.org/wiki/Schrödinger's_cat http://en.wikipedia.org/wiki/Schrödinger's_cat
- Ono-Sendai 12y ago
  I think the idea of time that does not exist, is one that is like a river, that has flowed past and can never be revisited.
Thiz 12y ago
I just came up with this stupid theory for the fun of it. Say time is self contained in the universe, just like all frames in a DVD. The process of going back and forth thru frames is what we call time, you need an observer capable of processing frames as input to produce information from them. Without the information processor, you still could see the universe as a whole (like the DVD) but not be able to see the frames stored in it in a sequencial manner. The only big difference between a DVD and the universe is that the latter is infinite. Well forget about it. If everything is self-contained then it gives determinism an upper hand against free will, and I hate determinism. Perhaps the universe is like a DVD being burned as we speak and free will still reigns? I said it was all for fun, don't be too hard on me. I always thought time was absolute, and perception was relative. Well, tell that to a god's particle before being created. There is no time in the void.
- PavlovsCat 12y ago
  I kind of enjoy to intellectually "know" (or think I know) that there is no free will -- certainly not to the degree our consciousness often thinks there is -- and still to appreciate and say yes to the illusion. I don't know why, but I still do :) Such is the power of the mind. You can know there is no free will and still believe there is, and you can know that belief to be false and still allow it in, like a dirty old dog you let sleep on the couch because its your favourite dog and you love it deeply. We can do that, and I find that beautiful. Also, from http://www.einstein-website.de/z_biography/credo.html http://www.einstein-website.de/z_biography/credo.html : > I do not believe in free will. Schopenhauer's words: 'Man can do what he wants, but he cannot will what he wills,' accompany me in all situations throughout my life and reconcile me with the actions of others, even if they are rather painful to me. This awareness of the lack of free will keeps me from taking myself and my fellow men too seriously as acting and deciding individuals, and from losing my temper. But I don't like that translation too much, so here is my own very slight variation on it: > I do not believe in the freedom of the will. Schopenhauer's word: "Man may be able to do, what he wants, but he can't will, what he wants", accompanies me in all situations of life and reconciles me with the deeds of mankind, even though they are quite painful to me. This realization of the unfreedom of the will protects me from taking myself and my fellow human beings all too seriously as acting and judging individuals, and from loosing my good humour.
gtrubetskoy 12y ago
There is a pretty fascinating Google Talk on this subject by Sean Carroll: https://www.youtube.com/watch?v=GFMfW1jY1xE https://www.youtube.com/watch?v=GFMfW1jY1xE
snarfy 12y ago
Here's my layman hypothesis: Time has a wave-like nature, not the particles. Since space and time are related through the Lorentz transformations, you could substitute a wave-like property of time and make the time dependent wave equation into a space dependent equation. The results would be the same, but it's a different interpretation. This is why you cannot measure a particles momentum and position at the same moment - they do not both exist at the same moment and depend on the current phase of the wave.

61 points by benbreen 12y ago

The philosophy of time is one of the remaining bulwarks of a philosophical position called 'dualism', which holds that minds are completely separate from our bodies: if you view us as being big ropes of particle-worldlines in a 4-dimensional fixed universe, you are basically stuck with describing us as "souls" who have latched onto this rope and are traveling along it, living the experience even though the future is as set in stone as the past. It makes relativity really easy to understand, but it makes entropy comparably harder (since the premise of entropy is that our uncertainties multiply due to particle collisions until things end up in more and more uncertain states). It almost sounds like there's no free will in this perspective, but that's not quite true. Instead you get a model of free will which is a lot like you see in the movie The Matrix: "Because you didn't come here to make the choice, you've already made it. You're here to try to understand why you made it." Relativity does not necessarily compel this. It is true, the relativistic "present" is a space between two light cones, and not just one plane. But that's not necessarily a huge obstacle: we can just pretend that there is one plane which is the "true present" and accept that the laws of physics make it impossible to know if we're truly right about which it is. As long as one of the planes is the true present you can lift up the Newtonian way of looking at time to the special-relativistic whole. It turns out that black holes aren't really so interesting as this article claims, because there is a 'co-moving' metric which falls into the black hole's event horizon in a finite time. What happens with a black hole is, you see someone slow down more and more to a standstill as they approach the event horizon, appearing to "merge in" with that surface, redshifting into the quantum noise of the Hawking radiation there. But from their perspective, you're just seeing their "last moment in this universe"; they'll keep going on past that horizon. But general relativity is still a problem. It describes the causal fabric of the universe as warped by the energies that inhabit each part of that fabric, and that makes it really hard to deal with time. Some of the interesting stuff here comes either from (a) alternative descriptions of relativity (like spinors/twistors, where you describe the entire world-line of a particle as a point), or (b) quantum mechanics (where you can do multiple-universe-splitting). The combination of relativity and quantum mechanics, for example, seems to give us the Wheeler-de Witt equation, which time famously "falls out" of (it plays no final role in the equation). Some physicists, notably Julian Barbour, think that this means we've got to fixate on a static universe. I'm totally undecided on this but I find it fascinating.

lg 12y ago
I don't think the frozen block view of time necessitates a belief in anything traveling along a world line (how would you express the speed at which it travels?) At any given point on your world line your brain is in some state and your 'mind'/conscious experience at that instant is what it's like to be that state.
- drostie 12y ago
  The "speed" of consciousness would just be in terms of the subjective rate of experience. But yes, that's a significant problem with appealing to this sort of attitude outside of this 4D world (you have to invent some notion of time which applies to souls but not matter). It is true that you can "step back" from the world-line and insist that every part of it is conscious, but that takes a really radical position on our own conscious experience of the progression of time, one that's actually distinctively Buddhist, if you can believe it. (There's a lot of Buddhist speculation about how the mind is a series of "aggregates" rather than one temporal whole; the idea is that you are no more identifiable with the you-of-twenty-seconds-ago than a candle's flame as it has exhausted a new quantity of vaporized oil: in a metaphorical sense we say that both "are the same" but we don't really mean much by it. In general though, saying that "the whole worldline is conscious" abdicates our notion completely that time progresses, and instead says it's all illusory (we have a local sense of progression even though nothing progresses). I think that the reason that this is unpopular is simply because if such an illusion exists, it has an interesting asymmetry with other illusions: you can't actually shake it. (It has some other problems, like: it's hard to see why natural selection would assemble those world-lines into something which have these feelings, given that they don't seem to do anything -- and of course natural selection becomes just a metaphor to describe a pattern in how the lines are structured, rather than a force which changes the world, so it's hard even to phrase the question much less answer it.)
Lambdanaut 12y ago
I have almost no experience with philosophy like this, but somehow have come to a very non-dualistic worldview of my own through a lot of thinking and writing in my personal journal. The whole "universe is a static 4D object" idea. I've never heard of anyone else talk about it before except myself. Are there any books that you can recommend that delve into the philosophy behind this?

inzax 12y ago

As shown on https://www.facebook.com/pages/Hacker-News/1558365107716690 https://www.facebook.com/pages/Hacker-News/1558365107716690

lisper 12y ago

http://blog.rongarret.info/2014/10/parallel-universes-and-arrow-of-time.html http://blog.rongarret.info/2014/10/parallel-universes-and-ar...

wuliwong 12y ago

I take umbrage with this part: "A past that can be revisited has not really passed. So, Gödel concluded, time does not exist." This is a very silly conclusion. My assumption is that the silliness is attributed more to the author of this article than to Gödel himself. Our intuitive concept of time from our existence at speeds very slow compared with the speed of light and at masses which are very small when compared to those necessary to bend space-time is not necessarily applicable to time in all regions of this speed-mass phase space. Particularly the regions where the speed is close to the speed of light and the mass is very large. There's just no logical path from the initial observation to the conclusion that time doesn't exist.

scobar 12y ago
I admit I'm well below the mental capacity to confidently state something as bold as "time does not exist", but I'd like to offer my thoughts. When thinking about Schrödinger's cat, [1] I imagined that the cat remained dead (and in every other possible state) even after the observer had confirmed the cat was alive. Every unobserved state did not collapse, but became inaccessible by means currently understood. Those states could still be observed by the same or another observer from a different perspective (i.e. revisiting the event). We just have to figure out how. [1] http://en.wikipedia.org/wiki/Schrödinger's_cat http://en.wikipedia.org/wiki/Schrödinger's_cat
Ono-Sendai 12y ago
I think the idea of time that does not exist, is one that is like a river, that has flowed past and can never be revisited.

Thiz 12y ago

I just came up with this stupid theory for the fun of it. Say time is self contained in the universe, just like all frames in a DVD. The process of going back and forth thru frames is what we call time, you need an observer capable of processing frames as input to produce information from them. Without the information processor, you still could see the universe as a whole (like the DVD) but not be able to see the frames stored in it in a sequencial manner. The only big difference between a DVD and the universe is that the latter is infinite. Well forget about it. If everything is self-contained then it gives determinism an upper hand against free will, and I hate determinism. Perhaps the universe is like a DVD being burned as we speak and free will still reigns? I said it was all for fun, don't be too hard on me. I always thought time was absolute, and perception was relative. Well, tell that to a god's particle before being created. There is no time in the void.

PavlovsCat 12y ago
I kind of enjoy to intellectually "know" (or think I know) that there is no free will -- certainly not to the degree our consciousness often thinks there is -- and still to appreciate and say yes to the illusion. I don't know why, but I still do :) Such is the power of the mind. You can know there is no free will and still believe there is, and you can know that belief to be false and still allow it in, like a dirty old dog you let sleep on the couch because its your favourite dog and you love it deeply. We can do that, and I find that beautiful. Also, from http://www.einstein-website.de/z_biography/credo.html http://www.einstein-website.de/z_biography/credo.html : > I do not believe in free will. Schopenhauer's words: 'Man can do what he wants, but he cannot will what he wills,' accompany me in all situations throughout my life and reconcile me with the actions of others, even if they are rather painful to me. This awareness of the lack of free will keeps me from taking myself and my fellow men too seriously as acting and deciding individuals, and from losing my temper. But I don't like that translation too much, so here is my own very slight variation on it: > I do not believe in the freedom of the will. Schopenhauer's word: "Man may be able to do, what he wants, but he can't will, what he wants", accompanies me in all situations of life and reconciles me with the deeds of mankind, even though they are quite painful to me. This realization of the unfreedom of the will protects me from taking myself and my fellow human beings all too seriously as acting and judging individuals, and from loosing my good humour.

gtrubetskoy 12y ago

There is a pretty fascinating Google Talk on this subject by Sean Carroll: https://www.youtube.com/watch?v=GFMfW1jY1xE https://www.youtube.com/watch?v=GFMfW1jY1xE

snarfy 12y ago

Here's my layman hypothesis: Time has a wave-like nature, not the particles. Since space and time are related through the Lorentz transformations, you could substitute a wave-like property of time and make the time dependent wave equation into a space dependent equation. The results would be the same, but it's a different interpretation. This is why you cannot measure a particles momentum and position at the same moment - they do not both exist at the same moment and depend on the current phase of the wave.