7 ms·

What if time's arrow can be reverted, and is being reverted all the time, but we don't notice it because, just like and omelet would become an egg, our brain st

What if time's arrow can be reverted, and is being reverted all the time, but we don't notice it because, just like and omelet would become an egg, our brain state would revert to a previous one? As far as we know time could be running in reverse, but the process in our brains would make us feel like it flowing forward. The book "Permutation City" explores this idea, albeit in simulated brains.

KingFelix 8y ago
Also check out some of the work that Daniel Sheehan is doing (from USD, not the lawyer) they just raised the needed funds to start a test on Quantum Retrocausation. Daniel also has a conference on Retrocausation, it's pretty great. https://experiment.com/projects/are-we-catching-photons-traveling-in-time https://experiment.com/projects/are-we-catching-photons-trav...
lisper 8y ago
That is in fact exactly what quantum mechanics predicts. http://blog.rongarret.info/2014/10/parallel-universes-and-arrow-of-time.html http://blog.rongarret.info/2014/10/parallel-universes-and-ar...
- selimthegrim 8y ago
  1) Galilean relativity actually plays a role in deriving the Schrodinger equation (at least convincing yourself it’s correct. See the books by Commins and Yaglom). 2) QM without statistical mechanics/thermo seems an odd basis to make prognostications about time or reversibility. Time isn’t an operator (see the classic Mandelstam-Tamm paper)
  - lisper 8y ago
    > Time isn’t an operator Yes, that's because time isn't actually a physical phenomenon. It's a kind of illusion, an approximation to the truth, in the same way that Newtonian mechanics is an approximation of GR in the weak-field limit. The wave function is a static, four-dimensional "thing" (it's not actually a thing, but I don't know of a more general noun). Our perception of a classical universe that evolves in "time" is not a reflection of a real underlying physical process, it's an emergent property of a sequence of subsets of the wave function in which entanglements have accumulated. Quantum information theory predicts the emergence of subsystems that are all in classical correlation with each other, i.e. a "classical universe". But none of this is actually real in a metaphysical sense.
    - deleted 8y ago
      [deleted]
b_tterc_p 8y ago
For all you know you don’t even experience time going forwards. At any given instance, how do you know that you “experienced” the past second. What if your conscious experience is just an instance at that point of existence? You can’t point to recollection of the past second because that recollection happens through time as well. What if that’s just an illusion of the brain state at that time? Did Descartes really think?
- halgir 8y ago
  Also known as a Boltzmann Brain. https://en.wikipedia.org/wiki/Boltzmann_brain https://en.wikipedia.org/wiki/Boltzmann_brain
  - rexpop 8y ago
    I am very grateful to be introduced to this concept. During--and occasionally since--a particularly traumatic psilocybin trip some years ago, I had the distinct understanding that my consciousness had only just been put together (or, rather, re-arranged from another, very alien form), memories and all. It is comforting to have such bizarre experiences reflected in others' thought experiments. Classically, we understand our neurological arrangement to be a function of each last instant's without discomfort. It's another thing entirely to consider how we might have been arranged from wildly different previous states. Although there's no compelling evidence to support it, neither is there a way to disprove it, I'm afraid.
    - AgentME 8y ago
      A really strange thing about Boltzmann brains is that if you suppose their existence, then the question "Am I a Boltzmann brain?" becomes complicated. It makes sense to ask "Is there a human thinking the thoughts I am thinking?" and "Is there a Boltzmann brain thinking the thoughts I am thinking?", but if you suppose the answer to both is yes, then when you ask the question "Which one am I?", there's no pure logic you can follow within your mind to answer that question, because both the human and the Boltzmann brain are in the same mental state and any logic either of them follow will be followed by the other, and any logic that comes up with a definite answer must be flawed because it comes to a wrong answer for at least one of them. Of course, it's not particularly useful to consider the Boltzmann brain version of yourself because a Boltzmann brain's decisions don't have any consequences. Time is better spent considering decisions by the consequences of the human taking them. Maybe this implies that you should choose to define "yourself" to refer to both your mental state combined with the ability to make decisions of consequence, and then you can safely disregard the strange kinship you may have with a Boltzmann brain. Though now this line of thought invites interesting questions about how to define what makes a decision consequential, and what exactly makes human decisions consequential...
MisterOctober 8y ago
Also, check out physicist Julian Barbour's notion that the universe is entirely static, and that our mind 'constructs' the illusion of time's arrow by orderings its perception of a collection of configuration spaces he calls 'nows'
- kgwgk 8y ago
  FWIW, he’s the author of the article.
  - MisterOctober 8y ago
    Zoinks! that'll teach me not to comment before reading the article. Thanks for the heads up! It's interesting how, in the OP, Barbour doesn't use much of the language he leaned on for "The End of Time' [1999, the source of the ideas I was referring to]. Maybe couching his ideas in more normal language is helping him reach a wider audience, which is great. Side note : I once emailed Barbour with some question about his view of Machian dynamics, and he emailed me back a thoughtful and kind reply - helluva nice guy p.s. his "other" book, 'The Discovery of Dynamics' aka 'Absolute or Relative Motion?,' is also a great read
    - p1esk 8y ago
      FYI, this article is based on his paper: https://arxiv.org/abs/1310.5167 https://arxiv.org/abs/1310.5167
- feanaro 8y ago
  Interesting, but isn't perception still a dynamic process requiring time? Or, said differently, how can a completely static universe support an apparently "evolving" perception?
  - bodi 8y ago
    Think of it like a map/reduce over rows in a database.
empath75 8y ago
> is being reverted all the time Think for a second about what you're saying here, and if it makes sense. What does 'all the time' mean in this context?
- roberto 8y ago
  Good point, I haven't thought of that.
  - xelxebar 8y ago
    I replied to GP, outlining a potential resolution. Thought you might like thinking about that kind of thing, so letting you know directly.
- laszlokorte 8y ago
  and what does "for a second" mean?
- xelxebar 8y ago
  It's not entirely incoherent, since time is relative to the geometry of spacetime and your trajectory through it. OP's original statement could be referring to the time coordianet in two separate frames of reference, so we might say that time (for us) is being reverted all the time (from someone else's perspective). It's even theoretically possible to have closed-timelike curves in general relativity, which means that time would literally loop for some set of set of observers. Any matter riding on these curves does have to have periodic dynamics, so in a sense it would be evolving and then reverting endlessly. To be fair though, the existence of such solutions to Einstein's equation is seen as problematic, since they raise questions of time-travel paradoxes and such. Also, I have only a passing familiarity with the details of the physics in such spacetimes, so take what I say with a hefty grain of salt.
veryworried 8y ago
Ah Eternal Return, it brings comfort to know that we may simply be living our exact same life over and over again for all eternity. Really motivates me to live to the fullest, to have the most enjoyable eternity.

KingFelix 8y ago

Also check out some of the work that Daniel Sheehan is doing (from USD, not the lawyer) they just raised the needed funds to start a test on Quantum Retrocausation. Daniel also has a conference on Retrocausation, it's pretty great. https://experiment.com/projects/are-we-catching-photons-traveling-in-time https://experiment.com/projects/are-we-catching-photons-trav...

lisper 8y ago

That is in fact exactly what quantum mechanics predicts. http://blog.rongarret.info/2014/10/parallel-universes-and-arrow-of-time.html http://blog.rongarret.info/2014/10/parallel-universes-and-ar...

selimthegrim 8y ago
1) Galilean relativity actually plays a role in deriving the Schrodinger equation (at least convincing yourself it’s correct. See the books by Commins and Yaglom). 2) QM without statistical mechanics/thermo seems an odd basis to make prognostications about time or reversibility. Time isn’t an operator (see the classic Mandelstam-Tamm paper)
- lisper 8y ago
  > Time isn’t an operator Yes, that's because time isn't actually a physical phenomenon. It's a kind of illusion, an approximation to the truth, in the same way that Newtonian mechanics is an approximation of GR in the weak-field limit. The wave function is a static, four-dimensional "thing" (it's not actually a thing, but I don't know of a more general noun). Our perception of a classical universe that evolves in "time" is not a reflection of a real underlying physical process, it's an emergent property of a sequence of subsets of the wave function in which entanglements have accumulated. Quantum information theory predicts the emergence of subsystems that are all in classical correlation with each other, i.e. a "classical universe". But none of this is actually real in a metaphysical sense.
  - deleted 8y ago
    [deleted]

b_tterc_p 8y ago

For all you know you don’t even experience time going forwards. At any given instance, how do you know that you “experienced” the past second. What if your conscious experience is just an instance at that point of existence? You can’t point to recollection of the past second because that recollection happens through time as well. What if that’s just an illusion of the brain state at that time? Did Descartes really think?

halgir 8y ago
Also known as a Boltzmann Brain. https://en.wikipedia.org/wiki/Boltzmann_brain https://en.wikipedia.org/wiki/Boltzmann_brain
- rexpop 8y ago
  I am very grateful to be introduced to this concept. During--and occasionally since--a particularly traumatic psilocybin trip some years ago, I had the distinct understanding that my consciousness had only just been put together (or, rather, re-arranged from another, very alien form), memories and all. It is comforting to have such bizarre experiences reflected in others' thought experiments. Classically, we understand our neurological arrangement to be a function of each last instant's without discomfort. It's another thing entirely to consider how we might have been arranged from wildly different previous states. Although there's no compelling evidence to support it, neither is there a way to disprove it, I'm afraid.
  - AgentME 8y ago
    A really strange thing about Boltzmann brains is that if you suppose their existence, then the question "Am I a Boltzmann brain?" becomes complicated. It makes sense to ask "Is there a human thinking the thoughts I am thinking?" and "Is there a Boltzmann brain thinking the thoughts I am thinking?", but if you suppose the answer to both is yes, then when you ask the question "Which one am I?", there's no pure logic you can follow within your mind to answer that question, because both the human and the Boltzmann brain are in the same mental state and any logic either of them follow will be followed by the other, and any logic that comes up with a definite answer must be flawed because it comes to a wrong answer for at least one of them. Of course, it's not particularly useful to consider the Boltzmann brain version of yourself because a Boltzmann brain's decisions don't have any consequences. Time is better spent considering decisions by the consequences of the human taking them. Maybe this implies that you should choose to define "yourself" to refer to both your mental state combined with the ability to make decisions of consequence, and then you can safely disregard the strange kinship you may have with a Boltzmann brain. Though now this line of thought invites interesting questions about how to define what makes a decision consequential, and what exactly makes human decisions consequential...

MisterOctober 8y ago

Also, check out physicist Julian Barbour's notion that the universe is entirely static, and that our mind 'constructs' the illusion of time's arrow by orderings its perception of a collection of configuration spaces he calls 'nows'

kgwgk 8y ago
FWIW, he’s the author of the article.
- MisterOctober 8y ago
  Zoinks! that'll teach me not to comment before reading the article. Thanks for the heads up! It's interesting how, in the OP, Barbour doesn't use much of the language he leaned on for "The End of Time' [1999, the source of the ideas I was referring to]. Maybe couching his ideas in more normal language is helping him reach a wider audience, which is great. Side note : I once emailed Barbour with some question about his view of Machian dynamics, and he emailed me back a thoughtful and kind reply - helluva nice guy p.s. his "other" book, 'The Discovery of Dynamics' aka 'Absolute or Relative Motion?,' is also a great read
  - p1esk 8y ago
    FYI, this article is based on his paper: https://arxiv.org/abs/1310.5167 https://arxiv.org/abs/1310.5167
feanaro 8y ago
Interesting, but isn't perception still a dynamic process requiring time? Or, said differently, how can a completely static universe support an apparently "evolving" perception?
- bodi 8y ago
  Think of it like a map/reduce over rows in a database.

empath75 8y ago

> is being reverted all the time Think for a second about what you're saying here, and if it makes sense. What does 'all the time' mean in this context?

roberto 8y ago
Good point, I haven't thought of that.
- xelxebar 8y ago
  I replied to GP, outlining a potential resolution. Thought you might like thinking about that kind of thing, so letting you know directly.
laszlokorte 8y ago
and what does "for a second" mean?
xelxebar 8y ago
It's not entirely incoherent, since time is relative to the geometry of spacetime and your trajectory through it. OP's original statement could be referring to the time coordianet in two separate frames of reference, so we might say that time (for us) is being reverted all the time (from someone else's perspective). It's even theoretically possible to have closed-timelike curves in general relativity, which means that time would literally loop for some set of set of observers. Any matter riding on these curves does have to have periodic dynamics, so in a sense it would be evolving and then reverting endlessly. To be fair though, the existence of such solutions to Einstein's equation is seen as problematic, since they raise questions of time-travel paradoxes and such. Also, I have only a passing familiarity with the details of the physics in such spacetimes, so take what I say with a hefty grain of salt.

veryworried 8y ago

Ah Eternal Return, it brings comfort to know that we may simply be living our exact same life over and over again for all eternity. Really motivates me to live to the fullest, to have the most enjoyable eternity.