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Basis of the Copenhagen Interpretation

  1. Sep 26, 2008 #1
    Bohr believed that the observer effected the outcome of an experiment at the subatomic level, and it wasn't necessarily the photons used to measure the particle like in Hesienberg's Uncertainty Principle that effected the outcome. What was the basis of this idea if the only way to measure something subatomic is with photons? Did he have any experiments to back up his idea? Was it based on the Double-Slit Experiment?
    Last edited: Sep 27, 2008
  2. jcsd
  3. Sep 27, 2008 #2
    Where exactly did Bohr expressed such a view?
  4. Sep 27, 2008 #3
    Maybe I didn't state what I wanted to ask clearly. Please correct me if I am wrong, but doesn't CI state that the photons used to change the state of a particle in the Uncertainty Principle weren't necessarily the direct cause of our lack of information on the particle? I just wanted to know what other experiments were used that didn't involve photons changing the sate of the particle.
  5. Sep 27, 2008 #4
    CI deals more with the relationship between subatomic realm and the observer. CI has 2 major precepts:
    1. there is no underlying reality
    2. observation creates reality.
  6. Sep 27, 2008 #5
    In my experience, it seems everybody has a slightly different take on CI. However, I don't believe "there is no underlying reality" is a necessary consequence. I think "we are unable to describe reality between measurements" may be a better summation of its principles.
  7. Sep 27, 2008 #6
    Copenhagen is definitely one of the more poorly understood interpretations. It is quite subtle.
    The statements below are too simple.

    1. there is no underlying reality.
    2. observation creates reality.

    The first statement begs the question "What is reality?"
    The second statement is not Copenhagen - Copenhagen says that the observer is part of the experiment and determines the set of outcomes - the experiment = observer + system. That is quite different to "observer creates reality".

    Unfortunately people use language quite loosely.
    Last edited: Sep 28, 2008
  8. Sep 27, 2008 #7
    I think I understand now.... Thanks!

    I still don't quite understand what experiment or sets of experiments that CI attempts to explain.
  9. Sep 27, 2008 #8
    Interpretations are designed to explain the theoretical framework of quantum mechanics as a whole, to give a person a physical application of how this theory describes reality. Thus CI, like all interpretations, seeks to explain any experiment pertaining to quantum mechanics, and they were developed in response to the demonstration of wave particle duality in the double slit experiment. They are not limited to the double slit, or individually limited to any particular experiment. Rather, they seek to explain all experiments dealing with quantum mechanical principles, as they interpret the fundamental principles underlying quantum mechanics. Thus far, all have been shown to be empirically equvalent, meaning they all predict the unique outcomes of experiments equally well. Because of the Heisenberg cut, some like Copenhagen and its offshoots(conciousness causes collapse) will be difficult to ever falsify, while others like GRW provide hope for falsification. However, they all attempt to describe the same thing.
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