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[Phys-L] Re: Physics (chem.) Humor

Jim Green wrote:

Is space empty when it contains fields. How is matter different from
its fields?

Oh my! Now we are about to reify fields. Well why not? We tend to reify
many concepts.

I take it that this sort of reification began -- or at least was
promulgated -- by the likes of StarWars. where they fight of "force fields"

Folks, fields don't "fill" anything -- nothing "contains" a field.

"Fields" are a mathematical invention which allegedly facilitate some

With regard to E&M fields . . . in the static case the field concept
certainly makes little difference. One can work directly with Coulomb's
law and get the same answers. So I suppose in the static case you claim
the field is just an mental construct that aids in problem-solving. But
when we consider charged particles in relative motion, we must treat the
field as real property of the space surrounding the charges in order to
account for the forces that act on the charges. If E&M fields are not
real-- just as real as the charged particles they affect-- how do we
account for the finite propagation speed of the information of each
particle's location as seen by all the other particles?

And how do we account for the propagation of light in empty space if the
fields are not real things? Isn't light a real thing?

Rodney Dunning
Assistant Professor of Physics
Birmingham-Southern College
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