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B Is the idea of fields ad-hoc?

  1. Dec 14, 2015 #1
    Are electric and magnetic fields real or are they just mathematical manipulations? Of course, one could say that we do not care about whether they are real or not, the only thing which matters is that they are useful in describing various things.

    But we assign quantities like energy, momentum to fields. So, shouldn't they be real if they have all these properties?
     
  2. jcsd
  3. Dec 14, 2015 #2

    fresh_42

    Staff: Mentor

    Do you have a radio in your car?
     
  4. Dec 14, 2015 #3
    Yes.
     
  5. Dec 14, 2015 #4

    fresh_42

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    And the radio program is transmitted by electromagnetic fields. Therefore they are as real as the music is played on the radio.
     
  6. Dec 14, 2015 #5

    jtbell

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    How would you tell the difference? That is, what exactly does "real" mean to you?
     
  7. Dec 15, 2015 #6
    Well, that would be difficult to define. But the problem I have is the concept of fields somehow seems too ad-hoc. It doesn't provide insight.
     
  8. Dec 15, 2015 #7

    Vanadium 50

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    Staff Emeritus
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    So you're defining "real" as "provides insight to you"? That seems like an odd definition, and not one I would use, but by that definition, no, they are not real.
     
  9. Dec 15, 2015 #8

    Dale

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    This is a purely philosophical question. Choose the answer you like.

    Thread closed.
     
  10. Dec 15, 2015 #9

    Nugatory

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    It does, however, allow us to construct powerful and general mathematical frameworks that do an extraordinarily good job of predicting the behavior of extraordinarily complex systems (It may be amazing that your car radio work, but nowhere near as amazing as that the person who designed it could reasonably expect that it would work while the design was still on paper). That's about as good as it gets in science.

    "Ad hoc" in the sense that you're using it is inherent in all science. We choose theories and mathematical frameworks because they match the behavior of the universe around us, and that's an ad hoc procedure. When Newton chose to formulate his law of gravitation, why did he put an ##r^2## in the denominator instead of an ##r^3##? What is so special about 2 other than that it happens to work?
     
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