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Simultaneous time

  1. Feb 4, 2007 #1
    Since this https://www.physicsforums.com/showthread.php?t=138637" related to Julian Barbour's theories was locked, I follow up with an interesting video documentary about his theories.

    http://noorderlicht.vpro.nl/dossiers/4032610/hoofdstuk/4032611/?noorderlicht.dossiers.one_man_and_his.hoofdstuk.julian_barbour&thema=wetenschap&category=noorderlicht" [Broken] (webpage is in Dutch but the documentary is in English.

    By the way: why was the prior topic locked?
    Is Julian Barbour now considered a crackpot by the resident moderator? :confused:

    By the way the site also has small documentaries of 't Hooft, Smolin, Kauffman and others.
    Last edited by a moderator: May 2, 2017
  2. jcsd
  3. Feb 4, 2007 #2


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    From Wikipedia:

    Is it really all that hard to understand?
  4. Feb 7, 2007 #3
    Time is not something physical, but motion/change is, from that we infer that there is time (as expressed by the measure of change, which can be measured by clocks).

    He can argue that time is "not real" but motion is something real.
  5. Feb 7, 2007 #4


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    I'd say its "case closed" if what heusdens has derived from the topic is correct.

    Motion is real and it is our only evidence that potential energy has become "energy". Whether you see energy at work as one facet of many that make up existence or as the driving force behind it doesn't really matter.

    Motion is an integral part of existence. Change is motion and change, as far as is possible to tell, is real, always has been and always will be according to the records. And the records of past changes are not just memories. They are detectable by geology, physiology, astromony and a host of other sciences.

    But time + energy seem to fall under the heading of measuring systems. To say that energy is physical is misleading. My understanding is that energy is our measure of motion and change.
  6. Feb 7, 2007 #5

    not necessarily so- an ensemble of all possible states also contains all possible histories corresponding to any possible physical laws- motion/change would only be an emergent illusion to causal structures in a causal history- as with the flow of time-

    like a flip-book of consecutive static pictures- a book which contained all possible pictures would contain all possible animations- it is the nature of the static states themselves which correspond to the output of some rule system at some arbitrary step in it's computation- since ALL possible states are in the ensemble every possible output at any step of an algorithm necessarily exists- therefore no actual motion change need exist: the nature of a causal observer who experiences the illusion of time/change/motion will observe the continuation of orderly predictable physics in their universe because probability restricts the possible next-states that they could observe given the complex interdependent structure of their present state- possible pasts and futures are restriced then to very specific outputs of very specific causal systems- namely the laws of physics in our universe-

    in short we observe motion and time because the kind of states that could have produced the complex structure of our sleves and environment *NOW* only correspond with the output states of very specific causal rule sets-
    Last edited: Feb 7, 2007
  7. Feb 7, 2007 #6


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    You have to admit that we are governed by the laws of physics in this universe and by those laws cause and effect are integral to the existence of this universe. With this in mind we can only define cause and effect as "change" and change requires motion.

    It may be true that each event has an event horizon of infinite probabilities but each event can only occur as a "result" or an "effect" of another event.

    One does not need to view this rule of cause and effect in a strictly sequencial fashion but we must acknowledge the requirement that one event supports the other. Whether this synergy of events is viewed as simultaneous or as a sequence is unimportant. What is important is that one event does not and cannot exist without the support of an other.
    Last edited: Feb 7, 2007
  8. Feb 7, 2007 #7
    strictly speaking we would say that change is a required fundamental property of any causal set- but that is already part of the definition of causality- at least the implication I guess- however there is no requirement for motion or causality for the Universe as a whole- only that it contains every possible state that a causal set can produce at it's output- [or at least the states that are have been observed]-

    this is a direct result of Causal Invariance http://mathworld.wolfram.com/CausalInvariance.html- it is possible for certain sets of causally invariant algorithms to produce causal networks- to observers in the network there is time and causality- but there is no correlation with the causal network and the order or number of steps that an algorithm performs to produce it- so while Motion/Change exists to observers in a causal network- it need not be fundamental to the universe generating the network- motion/time/causality can emerge arbitrarily from static structure if that structure is capable of universal computation- any static structure that contains the information of any possible state also contains the total output of any possible causal set [including all Universes with timelike dimensions] and is computational universal by definition- this is the essence of "Block Time" as conjectured by Page/Wooters/ Barbour/ Deutsch/ Wolfram
    Last edited: Feb 7, 2007
  9. Feb 7, 2007 #8


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    Very cool but the term "block time" is erroneous in that time is "the measurement of change" and unless the "block" is "changing" or "in motion" there is no need to use the term "time". An alternative would be "a simultaneous block of changes" or to that effect. Interesting topic.
  10. Feb 20, 2007 #9


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    But, then again, you can't define change if everything is changing at the same time so there could be no "block of simultanieous change". It wouldn't be change. It would be a collective motion of some sort that would remain imperceptible.(?)

    The idea and the perception of change depends upon relating one event to another. Events have to differ from one another in order to perceive any change at all.
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