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Time: An illusion?

  1. Sep 19, 2006 #1

    Not sure if this really falls under cosmology but anyway.
    I started reading this book by Julian Barbour called the End of Time a while ago and admitadely i havent gotten very far (started it a while ago, you know how it is :P) but i think ive got the jist of it, or at least something that makes sense. (BTW if anyone has read the whole thing and what im saying is not what the author says feel free to shoot me down in flames)

    As i see it, time is an illusion. I mean, that statement itself is flawed, because time is so intagable. What i mean is, time as a force, a dimension, a fundamental property of the universe, is an illusion. There is still the concept, the sensation of time, but it is nothing more than that. My reasoning? Entropy.

    For me there is no arrow of time. There is no time. Simply the space between events. Now you might say well that is time, but its not. Time as used by physicists is an underlying....thing... in our universe rather than a convienient name for the space between events. Why should it be anything more? We measure one second as the space between a certain event. Now you might say well where or what is this space? Your talking about a gap in time, which you said cant exist. Well, not really. Now i realise that its bad to use a definition to define itself but i feel here i have no choice. Its simply a delay between events, could be a multiple of other delays. What you must realise is just as there is no ether giving rise to relativistic properites, there is no time controlling our movements, there is simply action and reaction.

    As for the arrow of time, this, as i mentioned before, is explained by entropy. Entropy must always increase (overall anyway). Just as milk doesnt unstir itself from coffee so things dont happen backwards (to those that have read arcadia forgive my bastardisation of a good example :P), stars dont suddenly switch off and form protostars of cold gas and dust. Why? Not because time says so, but because this would violate the laws of entropy.

    This fits quite well with relativity. Ive heard many a time people explain time dilation by using the ball in a box example. If you have a bouncing ball in a box and each bounce is one 'tick' then the box (and ball) moves laterally the slower each tick because the ball is trying to keep up with the box and touch the bottom. This is not usually used as a literal explination, but i beleive its a very valid one in this situation.

    What do you guys think? (and as always, please, constructive crisitisim)

  2. jcsd
  3. Sep 19, 2006 #2
    What makes you think this?

    A dimension (like time, the familiar space dimensions, and other postulated dimensions) is simply a measure of the space between things. A meter or so separates me from my door. Five minutes or so separates me from the sending of this post to Physics Forums.

    I have never heard it suggested that it is time's fault that future situations can be difficult to revert to past situations. The reverse can also be true, it's just that the mechanism to make it difficult won't be entropy.

    I don't get your blue ball example. If it moves laterally, then the "floor" of the box does not move closer or further from the ball. Perhaps if it were a tall or an open-top box (so the ball doesn't hit the ceiling) moving downward (like jumping in an elevator).

    Perhaps I'm wrong about you, perhaps I'm wrong about time, perhaps I'm wrong about everybody else, but it seems to me like you are having misconceptions on how others are perceiving time, rather than everybody else misperceiving time. That said, you are in good company; Kant and Leibniz and many others vs. Newton and many others have said this sort of thing.

    Space isn't a thing either, it's just the space between things. And, confusingly, it expands. There's no equivalent to entropy for space, so there's no "arrow of space" (outside of a black hole).

    I just have to do this though:

    Is too.
  4. Sep 19, 2006 #3


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    What qualifies as real, and what qualifies as an illusion?
    I'm sitting here measuring time on my watch, and to me that makes "time" very real.
    Anyway, this isn't about physics, but belongs (at the best) under philosophy.
  5. Sep 19, 2006 #4


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    No, that is the definition of "time". You can't say that something doesn't exist if you also believe that the definition describes something that exists.
    It isn't anything more than a dimension. I don't know where you got the idea that physicists think it is something more, but you are not correct.
  6. Sep 19, 2006 #5
    In my views time is not an illusion but an abstaction and does not by itself exist.

    We can only speak of time when we refer to repeatable processes. If there are no repeatable processes, only changes, there is no measure of time at all, only a notion of change.
    So I conclude that time is an abstraction derived from the existence of repeatable processes.
  7. Sep 19, 2006 #6

    first off thanks for your comments, you all raise interesting points. in hindsight my post was probably quite ambiguous in meaning (misuse of words like dimension and thing :) ). ill have to have a think and come back with a better one!
  8. Sep 22, 2006 #7


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    Is "length" also an abstraction in your view?
  9. Sep 24, 2006 #8


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    There exist at least one definition of "time" and at least one definition of "illusion" so that "time" is an "illusion".
    (One such definition, or rather, part-definition of "time is: "Time is a type of illusion")

    Can't possibly see what's interesting with those points of view, however.
    Last edited: Sep 24, 2006
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