User talk:Sbyrnes321/Electricity from magnetism

"In this chapter we have seen how the fact of charge invariance implies forces between eleictric currents. That does not oblige us to look on one fact as the cause of the other. These are simply two aspects of electromagnetism whose relationship beautifully illustrates the more general law: Physics is the same in all inertial frames of reference." (emphasis mine, from Purcell Chap. 5).


 * its VERY clear that he's trying to communicate that it is a mistake to think of electrc force and magnetism as separate things.
 * remember your original question: "However, it is not apparent to me how the same principles can be used to explain how magnetic fields create electrical currents."
 * and then, from above "That does not oblige us to look on one fact as the cause of the other" indicates, clearly, as i've said, your question is based on a misunderstand.
 * and extract from my answer: "the physics of the currents and magnetic fields do not contain causality, better to think of them as a single thing"
 * this is so clearly what Parcell is saying, i have no conception of why you could think it was not, my wording is even eerily similar.

I think this quote proves that Purcell agrees with me: Electricity is not the "cause" of magnetism and magnetism is not the "cause" of electricity. Instead you should view them as two manifestations of a single phenomenon, electromagnetism


 * that is true, but NOT what you have been saying, you have all along claimed magnetism to be a twin or symmetric partner to electricity, your position is now failing to even be consistent, which before this is basically was.

(note the term: not "electricity" but "electromagnetism").
 * semantics, almost certainly done that way to imply joining up, for people unable to understand the full relativistic need to remove magnetism, as 'semantically' has now happened in electroweak. (this argument is not new on this thread).

OK? It's not just me and my cranky ex-physics-professor who think that electricity and magnetism are siblings rather than parent-and-child! Ed Purcell also agrees! And that's immediately after he has explained the famous current-in-a-wire example. --Steve (talk) 01:28, 11 February 2011 (UTC)
 * you say the "same phenomonon" YES, then shortly followed by "siblings" NO, this is contradictory.
 * and "parent-and-child" for the last time, there is only ONE thing, and magnetism is clearly the thing that is subsumed.

For magnetic monopoles, you want a "very clear definition of a monopole". The definition of a monopole is not ambiguous at all. Calculate $$\nabla\cdot \vec{B}$$. Wherever the result is nonzero, there is a monopole. Colloquially we say that a monopole is a "north" with no "south" (or vice-versa), or "half a magnet", but the really precise definition is the previous sentence. It is the universal consensus of professional physicists that it there may be elementary particles that are magnetic monopoles. Some think that monopole particles "might" exist, while others think they "almost certainly" exist, but no serious physicist believes they "cannot" exist. Their properties have been spelled out in detail: 't Hooft–Polyakov monopole, etc. Grand unified theories predict that they exist. String theory predicts that they exist. The claim that monopole particles "cannot" exist is a "fringe physics" claim.

Why is this important? If there are magnetic monopole particles, then everything in electromagnetism is 100% perfectly symmetric between electricity and magnetism. An electric current creates a magnetic field, and likewise a magnetic monopole current creates an electric field.
 * forget 'creates', check your own reference above, when there is ONE phenonomen, call it what you will, there can not be "creates" or "causes" or "gives rise too" etc.
 * i dont know the theoretical basis for the belief in monopoles, but you seem to imply its the symmetry between electricity and magnetism, i don't believe that to be the case, as i said, but assuming it, i'd have to conclude monopoles can't exist.

There is a "Coulomb's law" for magnetic monopoles, etc. Purcell, if he were alive, could in theory rewrite his textbook to start with magnetic Coulomb's law, change reference frames, and show that there has to be something called an "electric field" in order for special relativity to be satisfied.


 * no there is only a relativistic coulombs law, you are simply restating the exact same argument with slightly different wording.

It seems to me like you have only two choices: Do you claim that magnetic monopoles cannot exist (and therefore you are a "fringe physicist" disputing a universal consensus); or do you accept that monopoles can exist and therefore there is a fundamental symmetry between electricity and magnetism? --Steve (talk) 05:03, 11 February 2011 (UTC)


 * i already answered exactly that, it's pretty weak for you to expect me to change my answer based on you just saying its wrong.


 * BTW i notice that most of my last response was ignored, and now even your self-consistency has fallen away, since here, i guess, this is now only for your benefit, i'll only continue back on the discussion page, so that others can contribute or learn from the argument.

Sorry, but I'm more and more confused about what you're arguing. The primary thing I want to disagree with is what you said at first: Electricity is more fundamental and magnetism is less fundamental. Now, you're saying electricity and magnetism are fundamentally the same thing, "ONE phenonomen". Aren't these statements contradictory?? How can "one phenomenon" be more fundamental than itself?

If you will accept the second statement and reject the first, as I do, then I'm happy, we're done with the discussion. Any other disagreement that has come up, is probably mostly miscommunication. :-) --Steve (talk) 01:52, 12 February 2011 (UTC)