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Displacement Current

  1. Aug 6, 2009 #1
    Recently, I came across an interesting debate over the meaning of Maxwell’s “displacement current.” I wonder if you are familiar with this debate and if so what is your position? On the internet, you can find a paper on this topic by Nigel Cook here:
    http://www.wbabin.net/physics/cook.htm" [Broken]
    The paper suggests that to this day, the teaching of classical electromagnetic theory ignores this alleged “error” in Maxwell equations. He also quotes Mr. Ivor Catt for having “discovered” the error in a publication in Wireless World, March 1979; “The History of Displacement Current.” You can read about Mr Catt here:
    http://nige.files.wordpress.com/2008/04/catt-info.pdf" [Broken]
    I would appreciate your opinions on this topic.
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Aug 6, 2009 #2


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    So far as I can tell from the "paper" by Cook, the debate hinges on the following dissent:

    Maxwell (and all mainstream scientists) believe that electric-current is material, and electric and magnetic fields are generated by the charge current.

    Catt believes that electric-current is caused by electric and magnetic fields, resulting from the self-gravitation of these fields.

    I don't know what my position is on this, but I am certainly skeptical against Catt, especially since the debate seems to be entirely moot. I don't understand what observations Catt's interpretation can explain that Maxwell's cannot. Furthermore, I believe that Catt's objection is outdated, and was outdated even before he/she was born. Mainstream science, since the early part of last century, regards the distinction between matter and wave as arbitrary. Still, there are problems with electromagnetic theory that require, IMO, quite unsatisfactory resolution. If there were a more detailed exposition of Catt's interpretation, then I could decide if I agree.

    I did at least find the "bicycle wheel" amusing.
  4. Aug 6, 2009 #3
    Thanks for writing. To establish your position, it is helpful to read the discussion section on Wikipedia here:
    http://en.wikipedia.org/wiki/Talk:Ivor_Catt" [Broken]
    In this discussion there is a heated debate between three individuals that's interesting to read. I seems that the so-called Catt's' anomaly can be explained by classical electromagnetic theory as well as quantum electrodynamics. It seems that Catt's theory has not been accepted by mainstream physicist.
    Last edited by a moderator: May 4, 2017
  5. Aug 7, 2009 #4

    Vanadium 50

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    The so-called General Science Journal is a haven for crackpots and cranks. Is there anything in the peer-reviewed literature that supports any of this?
  6. Aug 7, 2009 #5
    No, there is nothing in the peer-reviewed literature to support any of this. However, the debate itself is interesting and I believe makes one think about how general principles developed through time. For example, Richard Feynman and others have said that the discovery of Maxwell's equations represents the greatest scientific achievements of all time. Yet, there are some people that believe that it isn’t Maxwell who deserves most of the credit, but rather Heaviside, Poynting and Gauss.
  7. Aug 7, 2009 #6


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    People seem to try and point this out for so many things. Science is rarely about one person that comes up with something new and fantastic. The last person that was even close to this description that I know of was Einstein. But people need to remember that Heaviside, Poynting, Gauss, Hertz, Ampere, Faraday and others are well known to any student of electromagnetics. Just like any student of relativity is aware of Poincare and Lorentz's work for example. Most people in the know are aware of the background work that led to the final culmination, Feynman least of all would know the background to Maxwell's equations. The thing is, most of this stuff is out there for anybody to find, but it took Maxwell to put it together. It took Einstein to think out the consequences that Lorentz and Poincare started to describe. Einstein also made key contributions to the problem of the black body radiator despite the fact that such brilliant minds like Planck were trying to solve it themselves.
  8. Aug 7, 2009 #7
    I totally agree. Your statement "… is out there for anybody to find" has never been more true, now that we all have access to the Internet. But having read about the personal lives of Newton, Maxwell, Einstein and others, one thing stands out: they all had plenty of time to devote to their science without the mundane distractions of everyday life that affect most people. In his book "Outliers" Gladwell suggests that it takes on average 10,000 hours to become good at anything.
  9. Aug 7, 2009 #8

    George Jones

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    I've closed this thread.

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