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Thread: Question about time...

  1. #31
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    The moment an instant lasted forever, we were destined for the leading edge of eternity.

  2. #32
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    Quote Originally Posted by gzhpcu View Post
    The present is what I am currently experiencing.
    So you're saying "the present" requires whatever elapsed time necessary to have an experience, right? I mean, I think we can agree you cannot experience anything in an arbitrarily short time, so when you say the present is what you are experiencing, then it must last long enough for you to have that experience. And, no doubt you realize that some kinds of experiences take longer than others, I don't know the physiology of it but the nervous system has various different timescales for various different types of signals to move around. Perhaps a complex thought, say an insight, requires more time than a simple sensation. So by your meaning, even "the present" cannot be regarded as lasting a given amount of time, it must be more fluid than that. Hence the various expressions about psychological time ("appreciate your kids now, the time will fly by until they grow up," or, "a watched pot never boils", etc.). So we see the psychological time may have the same arrow as the time a clock is capable of measuring (which depends on the oscillator it uses for its precision), but it cannot be the same thing. Indeed, the Heisenberg uncertainty principle establishes quite fluid limits on how well we can establish a time interval, based on the situation. So "the present" means various different things in different situations, and it's not a stretch to imagine its meaning at the origin of the universe is different than the one you defined above.
    Last edited by Ken G; 2017-Dec-03 at 03:03 PM.

  3. #33
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    Quote Originally Posted by slang View Post
    Not to a photon, at c. So why should time adhere to your description or our perception when we reach another limit, where t reaches zero and speed might cease to have meaning?
    Well, not being a photon, I am referring only to time as we perceive it. The time I am referring to in this discussion is that which we experience. Am not referring to QM extremes..

  4. #34
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    Quote Originally Posted by gzhpcu View Post
    Or maybe to put it another way: how can I get to the present from the past?
    It seems like the paradoxes that Zeno brought up. And about the original problem, I agree itís troublesome. But I think thereís another way to look at it. Suppose you have an infinite timeline. The chance of you being at a certain spot approaches zero, but at the same time you have to be somewhere...
    As above, so below

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    Quote Originally Posted by gzhpcu View Post
    Guess I did not make myself clear. I just said that I do not math in this instance, i.e., sequencing my memories...
    No one needs math

    If you refuse to consider it, in relating experience to math as an analogy for instance, you're just admitting defeat. There is no other area of human thought has dealt with the infinite more thoroughly.

    However, the problem you're considering is not unique to the time dimension--space extends out forever in all directions. We don't know the limits of that extent, in any direction, of space or time, and if there are limits how those limits occur, how the limits keep us from beyond those limits.

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    Quote Originally Posted by gzhpcu View Post
    The time I am referring to in this discussion is that which we experience. Am not referring to QM extremes..
    But that's exactly the problem I'm pointing out. You are applying a non-extreme notion of time to highly extreme conditions (t=0), and then seem surprised that leads to inconsistencies. you should only be surpised if it didn't!

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    Quote Originally Posted by gzhpcu View Post
    I know I am probably opening a can of worms here, but I have a rather simplistic question which has bugged me since childhood.

    The old model of the universe was that the universe always existed, will always exist for eternity. Problem here, I never could understand how we could ever reach the present, since the past was eternally long.

    Then the theory of the Big Bang showed up, and the question was what was before t=0? How could it start up?

    Now we speak of multiverses, bubble universes, branes colliding to create the Big Bang for our universe, etc. So these extend back infinitely (back to square one)

    So the question is: how could we ever have reached the (elusive, constantly changing) present if the past is infinite?
    No one knows the answer to this question. I think it is a great mystery. That is why I wrote, "The moment, an instant, lasted forever, we were destined for the leading edge of eternity."
    The moment an instant lasted forever, we were destined for the leading edge of eternity.

  8. #38
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    Quote Originally Posted by Ken G View Post
    So you're saying "the present" requires whatever elapsed time necessary to have an experience, right? I mean, I think we can agree you cannot experience anything in an arbitrarily short time, so when you say the present is what you are experiencing, then it must last long enough for you to have that experience. And, no doubt you realize that some kinds of experiences take longer than others, I don't know the physiology of it but the nervous system has various different timescales for various different types of signals to move around. Perhaps a complex thought, say an insight, requires more time than a simple sensation. So by your meaning, even "the present" cannot be regarded as lasting a given amount of time, it must be more fluid than that. Hence the various expressions about psychological time ("appreciate your kids now, the time will fly by until they grow up," or, "a watched pot never boils", etc.). So we see the psychological time may have the same arrow as the time a clock is capable of measuring (which depends on the oscillator it uses for its precision), but it cannot be the same thing. Indeed, the Heisenberg uncertainty principle establishes quite fluid limits on how well we can establish a time interval, based on the situation. So "the present" means various different things in different situations, and it's not a stretch to imagine its meaning at the origin of the universe is different than the one you defined above.
    Sorry, but in the context I am speaking about, I do not need to revert to QM or philosophy. I am talking about the pure and simple, every day context of the present, as the man in the street understands it. As I type, I am aware of the flow of time as my fingers type the words I am thinking about. I am not talking about Planck time units, I am talking about the simple flow of minutes.

  9. #39
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    Quote Originally Posted by Ken G View Post
    But that's exactly the problem I'm pointing out. You are applying a non-extreme notion of time to highly extreme conditions (t=0), and then seem surprised that leads to inconsistencies. you should only be surpised if it didn't!
    I am only referring to the Big Bang have occurred about 13.8 billion years ago. If I run my film backwards, I approach t=0. Yes, I know, QM and GR breakdown here...

  10. #40
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    Quote Originally Posted by gzhpcu View Post
    Sorry, but in the context I am speaking about, I do not need to revert to QM or philosophy. I am talking about the pure and simple, every day context of the present, as the man in the street understands it. As I type, I am aware of the flow of time as my fingers type the words I am thinking about. I am not talking about Planck time units, I am talking about the simple flow of minutes.
    Quote Originally Posted by gzhpcu View Post
    I am only referring to the Big Bang have occurred about 13.8 billion years ago. If I run my film backwards, I approach t=0. Yes, I know, QM and GR breakdown here...
    Your original question was
    Quote Originally Posted by gzhpcu View Post
    So the question is: how could we ever have reached the (elusive, constantly changing) present if the past is infinite?
    This is not a problem that is even talked about, much less solved, in the street! Not that anybody else has solved it...

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    Going by all your refutations of all the suggestions and explanations other people have responded with, in context with your opening question, I can't understand what it is you are looking for. Though I suspect that any answer that would satisfy you would involve everything from cosmology to cognitive science. Whatever it is you are asking it probably is unanswerable at this time because we don't know enough. But I think if you considered some of the other comments further you might find that they address misunderstandings that have contributed to your question.
    Last edited by Darrell; 2017-Dec-04 at 06:28 PM. Reason: Grammar. Yeah, funny, I know. But I try.

  12. #42
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    Dude, infinity could have started last Thursday, for all we know.
    Et tu BAUT? Quantum mutatus ab illo.

  13. #43
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    Quote Originally Posted by grapes View Post
    Your original question was

    This is not a problem that is even talked about, much less solved, in the street! Not that anybody else has solved it...
    Yes, sorry if I was unclear. I was contrasting the old universe is infinitely old theory to the original Big Bang theory. Just saying both seem unsolvable (to us). I know there is no answer provided by our current level of science.

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    Quote Originally Posted by Darrell View Post
    Going by all your refutations of all the suggestions and explanations other people have responded with, in context with you opening question, I can't understand what it is you are looking for. Though I suspect that any answer that would satisfy you would involve everything from cosmology to cognitive science. Whatever it is you are asking it probably is unanswerable at this time because we don't know enough. But I think if you considered some of the other comments further you might find that they address misunderstandings that have contributed to your question.
    Actually, I did not expect an answer. Was just expressing frustration at the current state of affairs.

  15. #45
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    Quote Originally Posted by Ara Pacis View Post
    Dude, infinity could have started last Thursday, for all we know.
    Yeah, we covered that in the (shudder) reality thread...

  16. #46
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    What is frustrating is that you ask a question about a difficult aspect of time, then insist on an answer that relates to,our perception of time passing. Well I can tell you the rate of perceived time depends on the rate of information received. Neither constant nor predictable because our brain can supply its own information! But none of that helps with cosmic time questions even if some people find meditation has cosmic implications for them. Perceived time is a psychological question. Time during the Big Bang is a theoretical physics question.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  17. #47
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    I think that almost everything said here misses the point of the
    original question, but Jens addressed it in post #34. It just
    seems impossibly weird that a single point on an infinite line
    could be special or unique or "now", but it is.

    -- Jeff, in Minneapolis
    http://www.FreeMars.org/jeff/

    "I find astronomy very interesting, but I wouldn't if I thought we
    were just going to sit here and look." -- "Van Rijn"

    "The other planets? Well, they just happen to be there, but the
    point of rockets is to explore them!" -- Kai Yeves

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    Quote Originally Posted by profloater View Post
    What is frustrating is that you ask a question about a difficult aspect of time, then insist on an answer that relates to,our perception of time passing. Well I can tell you the rate of perceived time depends on the rate of information received. Neither constant nor predictable because our brain can supply its own information! But none of that helps with cosmic time questions even if some people find meditation has cosmic implications for them. Perceived time is a psychological question. Time during the Big Bang is a theoretical physics question.
    Why do I insist on an answer that relates to our perception of time passing you ask? Because it is relevant to our being and we are constantly confronted with it. From our perspective, if we could move backwards in time, would anything change? As a hypothetical entity impervious to the forces of gravity as we approach the Big Bang...

    Am not talking about the clock pertaining to photons or elementary particles approaching the speed of light.

  19. #49
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    Quote Originally Posted by gzhpcu View Post
    Am not talking about the clock pertaining to photons or elementary particles approaching the speed of light.
    But, I think you are. You ask questions like this . . .

    Quote Originally Posted by gzhpcu View Post
    From our perspective, if we could move backwards in time, would anything change? As a hypothetical entity impervious to the forces of gravity as we approach the Big Bang...
    Which are questions about the nature, the properties of time and how they result in human perception of time. It is as if you want to skip right to the answer, which is perfectly understandable, but not practical. The answer you're looking for will include all of what modern science has discovered about time. You may not need to be informed of all that to have some understanding of the answer, but the answer can only be arrived at by understanding and building on what science has previously discovered about time. Unfortunately, modern science has not yet discovered enough about time to answer your questions beyond some degree of informed speculation. And it is all based on the currently "known" properties of time. Like how it is relative, for example.

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    Quote Originally Posted by gzhpcu View Post
    Why do I insist on an answer that relates to our perception of time passing you ask? Because it is relevant to our being and we are constantly confronted with it. From our perspective, if we could move backwards in time, would anything change? As a hypothetical entity impervious to the forces of gravity as we approach the Big Bang...

    Am not talking about the clock pertaining to photons or elementary particles approaching the speed of light.
    Is moving backwards in time the same thing as visiting the past? I think there are distinctions. If you move backwards in time at the rate of 1 second per second, you'd be standing still, freezing time from your perspective. You'd have to move backwards at a faster rate. However, does that create physical effects, such as occupying space and creating gravity? A lot of people get around this by moving forward in time through a shortcut, such as a wormhole or traveling really fast backwards in space where there is presumed to be less mass to interact with, or by claiming to use some sort of field effect to create a bubble that acts as a discontinuity.

    Come to think of it, the simplest answer is yes, you can go back in time as easily as forwards, but it merely rewinds the tape and you walk backwards and lost the information you learn. In other words if you could move backwards, you wouldn't be able to remember it.

    As for the rest of the question about why is one moment special? Perception. All moments are special, we just choose some to be more special to us than others. We choose these to be landmarks and count the time elapsed since then.
    Et tu BAUT? Quantum mutatus ab illo.

  21. #51
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    The duration of the present is infinitesimally small, it is the boundary between the past and the present. We use the word present in a much looser, broader sense...

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    Quote Originally Posted by gzhpcu View Post
    The duration of the present is infinitesimally small, it is the boundary between the past and the present. We use the word present in a much looser, broader sense...
    I thought it was limited to discrete units of Plank Time.

    The human nervous system has a finite speed (~60 MPH, IIRC), so we're all living in the past. Perceptions take time to be processed, and our bodies know this, hence the evolution of ganglia that trigger reflexes before the brain is aware of a stimuli. New research in human thought using MRI suggests there is an internal debate about how to understand perception, memories, processed results, etc. This may indicate that the brain itself is aware of the passing of time even while it is stuck thinking about events. Perhaps this is the base reason why our perception of time and the present is "a looser, broader sense."

    Luckily for us, we're the top predator and have the luxury of wasting time lost in thought. Prey animals have to react more quickly. Also, we're a large animals, so our movements are slower than smaller animals, and our proprioception may inform our sense of time as well. Smaller animals also have less distance for neural impulses to move, so they can react more quickly. The speed of small animals and insects compared to our own may also inform our prolonged sense of time. Our ability to play catch, tossing a ball into the air and preparing to intercept the parabolic arc power by gravity of a huge planet may also prolong our sense of time, since the motion can seem slow to us even though it is powered by forces much more massive than us (whether it be Earth's gravity or some cosmic entity).
    Et tu BAUT? Quantum mutatus ab illo.

  23. #53
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    Yes, right, assuming time is quantized.

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    Quote Originally Posted by Ara Pacis View Post
    I thought it was limited to discrete units of Plank Time.
    Nope. In current theories the Planck time has not been shown to have any physical significance at all. There is lots of speculation about it but it is just that - speculation.

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    Quote Originally Posted by Ara Pacis View Post
    The human nervous system has a finite speed (~60 MPH, IIRC), so we're all living in the past.
    Worse than that, we are living in multiple pasts. When you pick up a cup of coffee, the visual signal of your hand and the cup reach the brain in a few milliseconds but the touch sensation takes 100s of milliseconds. The brain has to make these both appear to be "now".

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    indeed the ability to predict which muscles to fire to throw a ball or walk, have to be learned and form an intricate set of predictions to achieve smooth performance. The ability to catch a ball for example is amazing when you consider the twin predictions of the incoming flight from vision and the coordination of muscles which are driven by neurons at quite slow speeds. So the brain can work in the future to do that but our sense of now stays continuous. If we try to think about it the automatic system falters, like the adage that if you want to ruin a golfer's swing, ask her to explain exactly how she does it.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    Quote Originally Posted by profloater View Post
    indeed the ability to predict which muscles to fire to throw a ball or walk, have to be learned and form an intricate set of predictions to achieve smooth performance. The ability to catch a ball for example is amazing when you consider the twin predictions of the incoming flight from vision and the coordination of muscles which are driven by neurons at quite slow speeds. So the brain can work in the future to do that but our sense of now stays continuous. If we try to think about it the automatic system falters, like the adage that if you want to ruin a golfer's swing, ask her to explain exactly how she does it.
    I have often thought that our hands actually have visual receptors.
    The moment an instant lasted forever, we were destined for the leading edge of eternity.

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    Quote Originally Posted by Copernicus View Post
    I have often thought that our hands actually have visual receptors.
    Insofar as heat is thermal photons, they kinda do.
    Et tu BAUT? Quantum mutatus ab illo.

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    Quote Originally Posted by Shaula View Post
    Nope. In current theories the Planck time has not been shown to have any physical significance at all. There is lots of speculation about it but it is just that - speculation.
    Isn't Planck time the time needed to cross the Planck length, so defacto the smallest time measurement possible?

  30. #60
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    Apparently Saint Augustine once said "I know what time is until you ask for a definition about it, then I can't give it to you"-

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