how to know whether you and you 1 second ago are essentially one and the same?

Discussion in 'Physics & Math' started by Secret, Aug 14, 2014.

  1. Secret Registered Senior Member

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    [do not assume it as a GR background question, its more of a general scope]
    One of the things about time is it put events in sequence
    But is there any way to prove that e.g. a particle 1 second ago is the same as a particle 1 second later?

    I.e. What actually give time its physical meaning, what actually allow a system at different times to be connected so that it is actually the same system all along, and not something like one second ago, it is system A, and one second later it looks like system A but is actually system B?
     
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  3. Arne Saknussemm trying to figure it all out Valued Senior Member

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    A lot of members are going to think what you are talking about here is nonsense. However, Zen Buddhism proposes much the same concept. If I am describing it correctly, they say we assume that the 'you' of now is the 'you' of a moment ago, but that there is no real reason (evidence?) to make that assumption. Is this what you are talking about?

    I'm editing this post to include this link: The Buddhist Concept of Impermanence

    This is what you're talking about, right?
     
    Last edited: Aug 15, 2014
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  5. cosmictraveler Be kind to yourself always. Valued Senior Member

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    Most particles that are elements will always remain the same unless something of a very great magnitude like a particle accelerator collides with it.
     
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  7. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    This strikes me as neither a physics question nor a mathematical one, it's more metaphysics or philosophy.
    1) how could you tell it wasn't the "original"?
    2) What difference would it make?
    3) What possible mechanisms could there be for "destroying" the first and "creating" the second?

    Uh... what actually gives distance its physical meaning, what actually allows a system in different places to be connected so that it is actually the same system all along, and not something like "one metre ago", it is system A, and "one metre later" it looks like system A but is actually system B?
     
    Last edited: Aug 15, 2014
  8. danshawen Valued Senior Member

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    3,950
    A very good question.

    Taylor and Wheeler 'space-time physics' have proposed an experiment as a stripped down derivation of time dilation that sports a rather baffling effect I call the inertia of energy (which is never actually discussed there!):

    A spaceship with a laser beam on one wall of the inside of the fuselage bounces from a mirror on the opposing wall. The spaceship has cut engines and is not traveling near anything gravitational, so it is an inertial reference frame traveling with near relativistic speed perpendicular to the laser and mirror traveling with it.

    Since no experiment can be performed that can inform the occupants of the spaceship of its position or straight line trajectory relative to the point where it cut engines, the energy of the laser beam travels along with the rest of the craft as though the photons had inertia, just like the rest of the spaceship and its observer / occupants.

    Is the energy of the laser beam "THE SAME 1 SECOND AGO AS IT IS 1 SECOND LATER?"

    In a manner of speaking, it is. The same argument goes for the matter that makes up the laser pointer, the mirror, the rest of the spaceship, and its occupants. It's as though matter were composed of energy that is stored in a "frozen" state, except that the matter is not any more "static" than is the laser beam in any real sense. The matter derives its inertial mass from moment to moment from the Higgs mechanism, from the vacuum energy in space. And the reason the matter retains its integrity as it propagates through space is because of the presence of the same fields and vacuum interactions as those experienced by the laser beam.

    Assuming the particle you have chosen is something stable like a proton, for example, it will surely be "the same particle", if there even is such a thing, 1 second later.
     
  9. kx000 Valued Senior Member

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    4,620
    Of course thing a and thing a one second later has been effected by time and grown. So same thing, but more mature.

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  10. Layman Totally Internally Reflected Valued Senior Member

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    There is actually no way to distinguish one single particle a second later from a second earlier. There is even no way to distinguish between that particle and another particle of the same type. It would take a large group of particles and look at the amount of decay among that group to determine a difference. Then even with a single particle, the rate of decay is completely random. It could happen at anytime or even change sometime randomly in the past. The idea even created the notion that the entire universe could be made of one single particle traveling back and forth through time, and each time it goes it adds one more particle to the universe. In a sense, quantum mechanics even allows for some Buddhist notions that everything is connected together as being all apart of one and the same thing. There is just no way to prove it either way.
     
  11. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    Given that there's an rather large "zoo" of particles, with significantly differing properties, that's a rather far-fetched idea.
    Even Wheeler & Feynman gave up on the "all electrons are one electron" idea because it wasn't really workable.

    Only if you read, and subscribe to, some inordinately bad pop-sci books/ writers.

    Which is entirely beside the point.
    We can't "prove" much.
    But one version (that things are the same) has a number of things in its favour: not least, it's a far simpler and massively less complicated explanation that works.
     
  12. Layman Totally Internally Reflected Valued Senior Member

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    So then you admit that scientist actually did work on this idea? Particles can combine and change to other particles. That process isn't really understood that well though (How particles can combine or transform into other particles). I rather liked the idea, because I don't really care for the particle zoo myself. I believe that there is actually one or a few underlying fundamental particles. It is just no one has been able to go beyond the standard model yet to show it. To me, particle interaction could make a lot more sense if they actually consisted of other particles that they emit in one form or another. They just wouldn't be able to have the same properties like mass, that would prevent people from making a viable theory about it. Or we could just assume that particles just vanish and magically transform to other completely different types of particles...
     
  13. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    Work on?
    No.
    Wheeler "proposed" it and Feynman shot it down almost immediately.
     
  14. Layman Totally Internally Reflected Valued Senior Member

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    Nice find, I think I remember reading about that. Although, I think it has been considered as a possible Big Bang model as well since then from that. If a particle traveled FTL, it would travel back in time and it would reverse a sign that could make it positive. Ironically, the particle pair fluctuation of the creation of the universe suffers the same problem similar to what Feynman suggested to Wheeler. There is not enough antimatter. Then Wheeler was hinting to the idea that protons could actually consist of positrons, an idea that would be beyond the standard model of particles.
     
  15. wellwisher Banned Banned

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    5,160
    Many years ago, during some of my earlier thinking, I noticed an observation that could provide one answer this question. If you compare a proton, for example, to the released sub particles which comprise proton, the sub-particles integrated as the proton, lasts much longer than the individual sub particles, after they are released in the lab by collisions. If start with a proton, it will last for billions of years. If we use a particle collider and break it down into its substructure, these same sub-particles no longer last billions of years but fractions of a second.

    One possible way to explain this time scale (longevity) difference with these two states of the substructure, is the proton and its confined substructure were permanently time dilated early in the universe, such that their clocks are running at a very slow pace in our reference. This allows its internal particles to appear to last for billions on years in our reference. When we collide protons and release these same sub particles, we change their time reference into our own earth reference, thereby changing their life expectancy.

    Other multiple time reference schemas are common within the universe, as inferred by GR and the different space-time wells around stars and planets. The center of the star is in a different time expression, than the surface of its planets, due to different positions relative to side-by-side space-time wells. We tend to average and treat these as the same, when applying force. But according to GR, the forces are acting in space and time, in ways that are not in phase when there are two different references interacting, with one going slower and one going faster in time.

    Relative to the question at hand, our long live matter (protons and electrons), by being in a more time dilated reference, is reacting to time differently, than the chemical expression of our cells, which is more attuned to our earth time reference. The slow clock adds an enduring capacitance that can't change as quickly, as the second by second changes, in our chemical make-up. Picture a large ship that is trying to turn. The wheel can be turned, side to side, but the inertia of the ship will continue to move forward, with the impact only slowly changing with time.

    Let me explain this with a variation of the twin experiment. We will have one twin in our earth reference and the other is aging slower in a time contracted reference on a space ship. The earth twin is sending instructions, to the other twin, through speed of light transmission. The first instruction is, Simon says, touch your nose. The first twin touches his nose as he gives the instruction, but notices the second twin is taking time to respond, due to his time reference running much slower. After twenty instructions, the earth twin is done, while the other twin has lagged behind and is only about half way done but still moving forward toward completion. The second twin is still in the immediate past; system defines a bandwidth of time and not a point of time.
     
  16. RJBeery Natural Philosopher Valued Senior Member

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    I don't think there's any way to prove this. Time has a meaning in our human experience but the flow of time does not exist in our mathematical models. There is no "now" and "then"; if anything, there is only a permanent four dimensional existence.
     
  17. youreyes amorphous ocean Valued Senior Member

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    actually you are never the same and are always changing.
     
  18. Dinosaur Rational Skeptic Valued Senior Member

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    For centuries philosophers had arguments/discussions relating to the concept of ongoing identity. They asked what is implied by the semantics of a statement like:
    I do not think they found a satisfactory answer.

    In modern times somebody conceived the notion of World Lines. (x, y, z, t) can be used to specify the space-time coordinates of something which can be called an event. The path of a particle becomes a set of event locations called a World Line.

    Now an object (animate or inanimate) can be viewed as set of related World Lines.

    It seems obvious that I at noon & I at one second after noon are not exactly equivalent. If I am eating lunch & perspiring, some atoms are added to me & some depart.

    Note that an incredible number of atoms are part of me for many seconds. Some are part of me for hours/days or a longer period of time.

    The concept of World Lines provides a more satisfactory answer to the above issue, namely:
    The above does not completely resolve the controversy, but it provides a more cogent point of view that any provided prior to the 20th century introduction of the concept of World Lines.
     
  19. Arne Saknussemm trying to figure it all out Valued Senior Member

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    This is true in the physical sense. The atoms of your body are in constant flux. I had thought that every seven years you are a completely different person physically. Now, I hear it's after only one year. In any case, say you are 49 years old? Every bit of you has changed either seven or 49 times. And yet you have memories of things that occurred decades ago. Who has these memories? What has these memories? Then there's the undeniable fact that a dead body appears to be an 'unoccupied' husk. We even speak of 'the body' distancing it from the person who formerly occupied it. All this seems like a pretty good argument for an immortal soul, or at least 'a ghost in the machine'.
     
  20. sculptor Valued Senior Member

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    5,999
    alternately:
    You are always the same and always changing.

    Actually, that must needs be a subjective analysis. Ofttimes, when i read something new, it offers an alternate perspective on known facts, and memories, which effectively changes the subjective analysis of past "knowledge". So, even the past is constantly subject to change. And yet, the core events of the "memories" remain the same.
    (one of the reasons that i hang out in science forums, or sculpture forums, is this rearrangement of "known" facts and impressions.)
    Change the perspective, and change the person.
     
  21. Arne Saknussemm trying to figure it all out Valued Senior Member

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    Your first sentence is brilliant, but please clarify or elaborate on your second paragraph, when you have time.
     
  22. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    Apart from the fact that this isn't what the OP was asking (go back and read it: is there any way to prove that e.g. a particle 1 second ago is the same as a particle 1 second later?), it should be noted that, barring drastic circumstances, regardless of the "changes" to a person, they're still recognisably[sup]1[/sup] the same person even years, or decades later.

    1 For varying values of "recognise" of course. Some people may have radical physical alterations (lost/ gained huge amounts of weight), psychological alterations... whatever. Yet they still manage to be, recognisably, the person that other people knew.
     
  23. Arne Saknussemm trying to figure it all out Valued Senior Member

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    Yes, but why? And they still recognize themselves as the same person - that is they have memories from decades past and 'feel' that they are the same person. Sometimes they are even surprised to look in the mirror to see how old or stout they've grown.
     

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