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A fundemental flaw in physics?

  1. May 22, 2003 #1
    i'm not quite sure if this belongs in this forums, but i've been wondering. how can we ever truly know something? are we right in calling an event a law of science that cannot be avoided simply because we repeatedly observe that event in an experiment? or, more simply, if we drop a stone a hundred times to the earth how can we ever know -truely know without a doubt- that it will fall again the next time? i'd imagine this could qualify as a fundemental flaw.
     
  2. jcsd
  3. May 22, 2003 #2
    What? Fundamental FLAW? More like fundamental LAW.
     
  4. May 22, 2003 #3
    ahhh... a paradox!
    in my terms to describe it as a LAW is contradictive because one can never know. (yes i relieze that this comment can spin on and on and on)
     
  5. May 22, 2003 #4
    Yes... this "problem of induction" was first raised by David Hume back in the 1700s, and it's been a central problem in philosophy, especially philosophy of science, ever since.

    Course, in the real world, we just assume the laws of science aren't changing on us, just like we assume the sun is going to rise tomorrow...
     
  6. May 23, 2003 #5

    Ivan Seeking

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    Re: Re: a fundemental flaw in physics?

    As much as we know that one day it won't.

    I think this question becomes more significant at deeper levels. Surely it does at the deepest levels where things like Gödel’s theorem could even sneak up to haunt us. In case our friend maximus is unfamiliar with this, Gödel’s Incompleteness Theorem basically shows that even mathematics cannot prove itself true.
     
  7. May 23, 2003 #6
    Re: Re: Re: a fundemental flaw in physics?

    physics is trial and error
    if there had some except for the Law
    then we should make a change for the Law
    until now the sun is rise every day , no esception
    so it's still a Law....not a flow
     
    Last edited: May 23, 2003
  8. May 23, 2003 #7
    Einstein said:" the most incomprehensible thing about the world is that it is comprehensible."
    if you believe the world is comprehensible
    then you should believe physics
    if the sun was raise at yesterday and raise today , but tomorrow not......than the world is incomprehensible
    but this is never happen in our world
    so i believe physics
     
  9. May 23, 2003 #8

    Ivan Seeking

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    He probably said this in opposition to the philosophies of Quantum Mechanics. On this point, it seems he was wrong. :smile:
     
  10. May 23, 2003 #9
    Firstly, we never stated that we know EVERYTHING. So if for instance the law of gravity works different then we described using the laws of gravity (GR), this would merely necessitate us to design a new theory, that matches observed facts.
    And the only reason for doing that is when we observe things, that can not be explained based on the existing laws.

    So in fact your problem you state, is not even a theoretical problem, but a practical one. It happened over and over in physcis.
    For instance Newton mechanics had to be replaced by relativity, to macth observations. Although in this case, the theory became before the observational proof.

    I think you ponder about what are the fundamental laws, and can we ever know them. The answer is that we proceed from relative knowledge and truths, and may find better knowledge and truth, but never absolute truth.
    In this sense, we never find absolute or fundematental laws, only relative laws.
     
  11. May 23, 2003 #10
    haha....
    you say quantum mechanics is incomprehensible
    i think you should more work hard to understand it
    quantum mechanics is tell us the probability
    but not incomprehensible of the world
     
  12. May 23, 2003 #11

    Ivan Seeking

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    now, now, I still have Feynman in my pocket:
    We can say how many of a million suns may rise, but as for ours I fear the morn.
     
    Last edited: May 23, 2003
  13. May 23, 2003 #12
    quantum mechenics show us the so unpredictable of the world
    but we still can describe why it will happen
    that mean it still comprehensible
    i think you should know what more about how the quantum theory working,
    you will know what the Feynman means
     
  14. May 23, 2003 #13

    Ivan Seeking

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    Well, I have mostly been joking but:

    When will an isotope decay?
    What is the physical mechanism for entanglement?
    Please describe the exact physical nature of an electron in a superposition of eigenstates.

    We have words for ideas that can be expressed mathematically. We have a tremendously successful model [QM]that is sometimes called more successful than all previous theories combined. This does not mean we understand it. You don't agree?
     
  15. May 23, 2003 #14
    yes...
    but i am discuss how many we understand about the world
    i know there have many thing we still need to understand
    but it doesn't mean it can not be understand
    i just say the world is comprehensible
    will you see the electron will suddenly become a proton??
    will you see the sun suddenly raise on west ??
    this call comprehensible
     
  16. May 23, 2003 #15

    Ivan Seeking

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    We agree. :smile:
     
  17. May 23, 2003 #16
    Thank:smile:
     
  18. May 23, 2003 #17

    drag

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    We don't, but it seems likely. :wink:
    Also, it is the only possibility that
    we can explore in this case because other
    possibilities are essentialy infinite and
    we don't have any preferences amongst them.

    Live long and prosper.
     
    Last edited: May 23, 2003
  19. May 23, 2003 #18

    marcus

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    Ivan I would like to know you better. I like how you put these two things. The Feynmann epigram in the pocket. And the nearly iambic sound of the "fear the morn" line----is that a quote from somewhere or do you just put a literary touch on things now and then? this is a nicely tossed off post:

    **********

    now, now, I still have Feynman in my pocket:

    quote:
    --------------------------------------------------------------------------------
    Anyone who understands Quantum Mechanics hasn't studied it long enough
    --------------------------------------------------------------------------------



    We can say how many of a million suns may rise, but as for ours I fear the morn.

    ************

    As for the original question, this was solved by Bayes was it not?

    I suspect as a philosophically sophisticated person you must know the Bayesian inference model.

    this is already a long thread and no one has told maximus about
    that way to resolve his difficulty

    Were you the person who wandered into the Astronomy game with a neat question about the event horizon a few days ago. I confuse names, but I think it may have been you
     
  20. May 23, 2003 #19

    Ivan Seeking

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    Thanks. No just me. I get a little philosophical from time to time...especially at 3AM

    No that's news to me. I will read up on this. And yes I'm the troublemaker with the event horizon problem. In the end, I wasn't sure if this interpretation is correct or not. Someone objected claiming this is merely a matter of semantics
     
  21. May 23, 2003 #20

    marcus

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    Not to worry, the person might have said "semantics" and meant "sour grapes".

    Bayesians are a minority among probability theorists, but a respectable one. For many years the most eminent prob. theorist/game theorist at UC Berkeley was a Bayesian named
    Blackwell.

    I cant give anything but the most simplistic account. A Bayesian begins dropping bricks with an arbitrary probability distribution according to which the brick might just as well fall upwards. Each time he does the experiment he recalculates his probability distribution (which becomes a way of describing his info about the world or his beliefs about physical law or his expectations of what will happen). he uses a calculus of "conditional probabilities" developed by Bayes----who thought this was all highly sensible.
    The more he drops the brick and recalculates his subjective probabilities describing his expectations the better they get.
    Bayes and the Bayesian school make this sort of rigorous and prove theorems about it. Superficially or at first sight it may seem
    ----well----either dumb or obvious. But that may be mostly because of my shallow view of it. I dont know any books to read about Bayesian theory.
     
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