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How does physics work?

  1. Sep 27, 2006 #1
    Do physics start with a set of basic assumptions, and from there, derive a theoretical system that fits well with experiments? Can the best physical theory explain everything?( Including its own underlying assumption as a deductive system)

    Can physics answer the question: why is there something, instead of nothing?( even the existence of the laws themselves)

    Can physics explain the emergence or happening of the big bang? if so, then what underlying assumptions is needed?

    if physics is more or less about finding regularities in nature, and calling it laws of nature. Do the laws emerge 'before'( i know the absurdity of using before) the universe? if so, then if there are no laws, how did the universe emerge?
    Did the universe 'precede' the laws? if so, if there are no universe, how did the law emerge?
     
  2. jcsd
  3. Sep 27, 2006 #2

    chroot

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    Yes.

    No one knows.

    No, nor does it attempt to answer this question.

    Physics endeavors to explain what happened for all times after the big bang; it may never have anything to say about anything "before" the big bang or "outside" the universe.

    Again, the study of 'physics' as it is currently known is not concerned with things outside the universe, as such questions have no answers.

    No one knows if all possible universes share the same laws, or whether every universe has unique laws. No one even knows if the concept of "multiple universes" is even sensible or meaningful.

    - Warren
     
  4. Sep 27, 2006 #3
    the regularities observed in nature( natural laws) are taken for granted that it will always work. This assumed invariances is based on inductive reason, the future work more or less similar to the past, and the assumption that 'past', 'present', and 'future' are knowable, and real. Until physics can explain why the laws are the way it is, the discipline will always be in unstable ground in fullfilling it s objective. It will always be unstable, for in any inherently explanatory system, it invoke undefines. The only true, ultimate explanatory system is one that explain it own existence from the level of axioms up.
     
  5. Sep 27, 2006 #4

    ZapperZ

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    I could also claim that your "theory" on physics is also "unstable", and in fact, less verified than physics itself (have you proven the validity of it?). So, in essence, you are using speculation to analyze something that has a more definite form.

    So how logical do you think that is?

    Zz.
     
  6. Sep 27, 2006 #5
    Wrong. mine was a commentory, and not a explanatory system.
     
  7. Sep 27, 2006 #6

    ZapperZ

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    In other words, your "commentary" requires no justification whatsoever to show that it has some degree of validity? Then why even bother? Every Joe Schmoe then can produce his own commentary and then we get what? If you have no leg to stand on to show that what you have come up with is true, then you have made a purely speculative post pulled out of thin air.

    Zz.
     
  8. Sep 27, 2006 #7

    Astronuc

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    It's all in the math. :biggrin:

    It's interesting and even amazing to be able to model/simulate and predict the performance/behavior of many phenomona/systems - but we do - on a daily basis.
     
  9. Sep 27, 2006 #8
    I don t understand what it is it that you don t understand. Can you at least help me out on that?
     
  10. Sep 27, 2006 #9
    Correct!

    I disagree, the objective of physics is not to explain things but to extract natural laws from experiments so that we can predict nature's behavior.
     
  11. Sep 27, 2006 #10
    So.. what is it that your are trying to drive at astronuc?
     
  12. Sep 27, 2006 #11

    chroot

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    kant, do you actually have a point? If so, please make it. This thread doesn't amount to much at the moment.

    - Warren
     
  13. Sep 28, 2006 #12
    In order to explain nature, one must understand why laws are the way they are. That is unattable
     
  14. Sep 28, 2006 #13

    Astronuc

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    I was trying to make the point that we observe the world/Nature, and we use physics and mathematics to explain how it works, and we even manipulate it rather successully, and sometimes not so successfully.

    We develop models that explain Nature and the world around us.

    What physics doesn't tell us is why things are the way they are, and physics never will.

    Perhaps there are unsolvable mysteries about the Universe and Nature, but that doesn't mean physics is not useful.

    The mathematics and physics we have at hand is quite useful and reliable, but we can always do better, and we strive to do so.
     
  15. Sep 28, 2006 #14
    I read somewhere that rather then all times after the big bang physics only attempts to explain everything after 1 plank time after the big bang. Is this correct?

    And if so, is it because nothing can be known before that? Or laws were not in place or something?

    ~Gelsamel
     
  16. Sep 28, 2006 #15

    chroot

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    Current theories cannot accurately describe events before the Planck time, but it is hopeful (inevitable?) that future theories will be able. Our current theories are known to be incomplete.

    - Warren
     
  17. Sep 28, 2006 #16
    you are very rude. that is a point.
     
  18. Sep 28, 2006 #17
    So does this suggest that laws are either non-existant before plank time or are different?


    ~Gelsamel
     
  19. Sep 28, 2006 #18

    selfAdjoint

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    Not in the least, any more than the fact that we can't see objects over the horizon implies that there are none there. It is OUR theories and models that fail there, not Nature's.
     
  20. Sep 28, 2006 #19
    I understand.
     
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