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Should objects that are connected share the same physical laws?

  1. May 15, 2014 #1
    Hi,

    Consider the various kinds of objects we have in our universe, from the smallest to the largest - sub-atomic particles, atoms, molecules, single-celled organism, multi-celled organisms, cities, countries, planets, stars, solar systems, galaxies, collection of galaxies, universe.

    Since they are all connected in some fashion, should they share the same physical laws? For example, space is connector of everything. So since they are all connected, should they all share the same physical laws? Because if they don't, they wouldn't really be connected which is a contradiction.
     
  2. jcsd
  3. May 15, 2014 #2

    UltrafastPED

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    Most scientists assume that physical laws are universal; this was not true prior to Galileo, Newton, etc. The philosophers taught that the laws of earth and the heavens were different.
     
  4. May 15, 2014 #3
    Not only laws of heaven and earth, what about freewill? Do all humans also fall under the power of these laws? If yes, then isn't the entire universe a single entity being governed by these laws?
     
  5. May 15, 2014 #4

    phinds

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    Now you are going off into wildly speculative philosophical stuff that is best discussed on some other forum. Read the forum rules.
     
  6. May 15, 2014 #5
    Ok fine, forget freewill or humans or universe being a single entity.

    What about my first question? Are there any physics theories out there that theorize that if two objects are connected, then they should share the same physical laws? I understand that the physical laws are the same for everything but is that an assumption or is there a proof for it? Ya I also know that efforts are underway for a Theory of Everything etc. But the most basic question is - If two objects are connected physically, then do they share the same physical laws? If so, are there any proofs for it?
     
  7. May 15, 2014 #6

    Nugatory

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    It is an assumption, with no proof but also no counterexamples, that the same physical laws apply to everything.
     
  8. May 15, 2014 #7

    TumblingDice

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    Physics doesn't work with or create "proofs". Theories and models are suggested, and then physicists design experiments to test against to determine if they ever fail...

    Can you think of an experiment that might show two objects you define as connected obey different physical laws?
     
  9. May 15, 2014 #8
    Physical laws can change if something new discovered. If someone finds something that is much faster than light, the laws will certainly be changed.
     
  10. May 15, 2014 #9

    TumblingDice

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    How does this relate to connected objects sharing the same physical laws? Please don't hijack the OP's thread with unfounded, speculative statements.
     
  11. May 15, 2014 #10
    Ah, you are posing the question back to me now :)
     
  12. May 15, 2014 #11

    TumblingDice

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    That wasn't the intention, but an unavoidable result. :wink: Actually, sometimes experiments can confirm what models and theories propose. Gravitational lensing, time dilation, and neutrinos for example. Proposing physical laws that do not operate in a consistent manner goes against the grain of modern physics. And yet trying to find examples of this, whether separated by space or by time, is still aggressively pursued today with more new ideas for new experiments.
     
  13. May 18, 2014 #12
    There are cases where the laws appear different. For example, planets move in almost circular orbits around the sun. If, however, I put a large ball in the center of a flat parking lot and roll smaller balls past it, they proceed in straight lines and do not orbit. I could interpret this to mean that celestial objects and balls in a parking lot are governed by different laws of physics.

    Of course we all know the true case is that gravitation does exist between balls in a parking lot but that the effect is so small that it cannot be measured.

    If different laws of physics apply in different circumstances then 1 of 2 cases must be true...

    case 1. There is a logical reason why the laws differ from circumstance to circumstance. Once discovered, this reason can then be incorporated into physical theory. Since we would then know how and why the laws apply in differently in different circumstances, they would no longer appear qualitatively different, only quantitatively different. This is what happened when Newton described the law of universal gravitation. All of a sudden the laws governing the movement of celestial bodies and the law that holds us to the surface of the earth were seen to be the same thing, experienced in different ways.

    Case 2. There is no logical reason why the laws differ from circumstance to circumstance. If this is true then we do not live in a universe governed by physical law and the study of physics is a useless and futile endeavor. So far this does not seem to be the case.
     
  14. May 18, 2014 #13

    ZapperZ

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    This is rather vague, because you haven't really specified what you mean by "physical laws".

    Let's pick an example, and then you tell me what you mean using that example.

    I connect a chunk of superconductor with another metal that isn't a superconductor.

    Are there any physical laws that they share? Sure! Gravity, laws described by classical mechanics, etc...etc.

    But, at the same time, there are also physical laws that describe only the superconductor, but not the ordinary metal, and vice versa. Otherwise, if all the same description can be used for both objects, they won't be different, would they?

    See the ambiguity here?

    Zz.
     
  15. May 18, 2014 #14
    Are you saying that your example is against the claim that there can be a Theory of Everything? If there can be a Theory of Everything, which is the holy grail of physics, then sure there will be laws that describe both the superconductor and the ordinary metal connected to it.

    Rephrasing my question, I am asking if connecting two objects creates a super-object that is the combination of these smaller objects or do the two objects still remain as two distinct objects? After all, what is an object? Is it just a collection of particles? If yes, then what is the space connecting the two objects made up of? Lets say that space can also be described by elementary particles. Then there must be laws governing these particles as well. And if the laws governing the objects and the space between them is the same, then an object connected to another object can be a super-object governed by a single theory. If the laws for space surrounding the two objects and laws for the two objects themselves are different, then perhaps the two objects couldn't be connected in the first place?
     
  16. May 18, 2014 #15

    ZapperZ

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    Do a search on PF on "theory of everything" and you'll find my argument on why such a concept is a fallacy for most of us condensed matter physicists. Better yet, go read Anderson's "More is Different" essay.

    You did not attempt to explain what you meant by applying it to the example that I gave. So devoid of such clarification, there is no way for me to address your question. Maybe others can decipher what you mean, though I don't see how based on what you had written.

    Zz.
     
  17. May 18, 2014 #16
    I did a search on PF for "theory of everything" but there are way too many results. I did go through a couple of them but couldn't find what I was looking for. I also didn't understand what you meant by "FDR by argument". I did a google search for the same but I don't understand the slang, sorry!

    By physical laws, I mean a theory that can explain both the connected objects and the space surrounding it.
     
  18. May 18, 2014 #17
    Reading "More is Different" essay now.
     
  19. May 18, 2014 #18

    ZapperZ

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    FDR was a typo/autocorrect on my iPad. I've corrected it.

    Search for my posts that highlighted both Anderson and Laughlin's articles. Or do a google search on Laughlin's Nobel prize speech. Pay attention to what is described as emergent phenomenon, and why this "theory of everything" is the theory of everything for reductionism!

    Then show this in my example. It one thing to claim it, it is another to show it via a concrete example.

    Zz.
     
  20. May 18, 2014 #19
    I am not claiming anything! I am just asking a question.
     
  21. May 18, 2014 #20

    ZapperZ

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    And I gave you an example where I asked if the the two different systems requiring different physical descriptions would constitute as not have the "same" physical law. You instead counter-argued using a concept that is still highly debatable, as if this is a done deal.

    If you believe in the existence of the theory of everything, then you had already made up your mind. So what is the point in asking anymore?

    Zz.
     
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