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I What does the act of observing do exactly?

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  1. Apr 24, 2016 #1

    benorin

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    My question is simple though I fear the answer may be complex: What does the act of observing do exactly? I hear observing does some unexpected things in quantum (I wouldn't doubt there is a religon based on it).

    I am a math major with a love of physics though I'm not that versed in it so please do pile on the formulas if you wish but be nice with the physics. Thanks for responding in advance,

    -Ben Orin
     
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  3. Apr 24, 2016 #2

    A. Neumaier

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    It may range from checking whether a silver spot is on the left or right to a click in a photodetector to recording a number in the memory of a computer. It even may mean doing months of calculations and checks based on collision experiments to measure the mass of the Higgs particle.

    That the act of observing does something to the observed system is of the same kind as that observing timid game. However, microscopic events are sometimes so timid that one usually (i.e., except in nondemolition experiments) cannot avoid at all affecting the observed with the observation.

    The claims of the Copenhagen interpretation that an observation forces the state vector to collapse to an eigenstate of the operator observed corrsponding to the eigenvalue measured is an approximate idealized description of the measurement process, appropriate in simple cases (only).

    The claim ignores that observations take time, that measurement results ae often inaccurate, and that many real measurements are not related to an operator but rather to a POVM. It also ignores that observation is done in the frame of an observer, and that different observers may therefore - in the same situation - measure different things. Finally, it completely abstracts from what it means to make a measurement/observation.

    As a mathematician you'll probably like my online book on quantum mechanics.
     
  4. Apr 24, 2016 #3

    A. Neumaier

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    You'll see that interpretations of quantum mechanics are like religion - fiercely debated, without the possibility to reach agreement. The agnostic part is called shut-up-and-calculate, but it leaves unanswered all important questions of how the math relates to reality - or answered ad hoc on a subjective case-by-case basis in terms of pieces of unreflected material from one or more of the established religions.
     
    Last edited: Apr 24, 2016
  5. Apr 24, 2016 #4

    A. Neumaier

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    It should read: ''Thanks in advance for responding'' - unless you think we have time machines.
     
  6. Apr 24, 2016 #5

    :-)


    Relativistic??
     
  7. Apr 24, 2016 #6
    From my reading of W. Heisenberg and H. Stapp (who subscribes to Whitehead's view) I got the simplest answer: the act of observing does physical reality - that is, the physical reality consists of observation acts (events); but events are connected by the underworld ("realm") of potentiality which is what QM calculates.
     
  8. Apr 24, 2016 #7

    A. Neumaier

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    And what about the reality before there were observers? Did our universe emerge from the preexisting underworld the moment when the first human (or the first amoeba?) observed something?
     
  9. Apr 24, 2016 #8
    Well, yes, when the observation process started, the universe emerged;
    how exactly it started is not a scientific question...
     
  10. Apr 24, 2016 #9
    People generally act different when they know they are observed.
     
  11. Apr 24, 2016 #10
    Huh???
     
  12. Apr 24, 2016 #11

    A. Neumaier

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    So do photons in a double slit experiment.
     
  13. Apr 24, 2016 #12
    Most deep questions are not scientific. One cannot build anything from just fundamental particles as most classical processes emerge and are not resultant of properties of fundamental particles. Embrace emergence, it's already established as science.
     
  14. Apr 24, 2016 #13

    A. Neumaier

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    All classical processes emerge as good approximations of the interplay of fundamental quantum fields.

    Nothing can emerge unless it results from more fundamental processes.
     
  15. Apr 24, 2016 #14
    Fundamental processes is not the same as fundamental particles in your usage, right? Because if not, pretty much nothing that we observe can be derived from the properties of electrons and quarks. I digressed but i got the idea that some participants in this thread are of the opinion that science has closed most chapters. No, we can only describe what we observe and at this point it's almost as if the fundamental mechanics of reality are invisible.
     
  16. Apr 24, 2016 #15
    How so?
     
  17. Apr 24, 2016 #16

    A. Neumaier

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    For each level that is not fundamental there is a more fundamental level below from which that level emerges as a n effective theory.

    Of course it will always be unknown whether what we regard as fundamental is not also only a level with more below. But I wouldn't be surprised if with quantum gravity plus the standard model we already reached the bottom.
     
  18. Apr 24, 2016 #17
    Yes. And taken at both ends, we can never deduce what we observe from the lowest level of fundamental particles. Just looking at electrons and quarks you'd never deem possible the emergence of vision, metabolism, hunger, appetite, bacteria, rain, computers, grannies, etc
     
  19. Apr 24, 2016 #18
    But all those phenomena can only be explained coherently because of knowledge of quarks

    That's why science is the best explaining g tool humans have invented, nothing g Is better or even close.
     
  20. Apr 24, 2016 #19
    Quite the opposite - 'knowing of quarks' explains nothing of the observed behaviours i referenced above. QM would be the worst example one can find for describing observed reality in ALL fields of science. Period.
     
  21. Apr 24, 2016 #20
    I disagree, we can explain chemical bonds by QM, that = everything.
     
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