Talk:Field theory

Andy, I'm not going to undo something you've written, but a force field and action at a distance are the same thing. Action at a distance means precisely that - one object, affecting another, without touching it. A force field is precisely that - an object generates a field of force around it, which allows it to affect objects without touching them. JacobB 21:22, 15 November 2009 (EST)

Action at a distance certainly is not the same as electromagnetic waves, which do not act instantaneously on a distance object as Newtonian gravity does. Perhaps the meaning of "force field" is ambiguous (it's not defined in my dictionary).--Andy Schlafly 21:24, 15 November 2009 (EST)

You're absolutely right. Newtonian gravity is a theory which implies instant transmission of gravity, and Maxwell's equations set a speed limit. However, both theories constitute "action at a distance," and both constitute "field theories." The term "field theory" is used for theories like Newtonian gravity, Maxwell's electromagnetism, or quantum field theory BECAUSE they describe action at a distance - in opposition to theories like quantum chromodynamics, or general relativity as it is currently incorporated into the standard model, which describe forces as being carried by particles - photons, gravitons, etc. JacobB 21:29, 15 November 2009 (EST)

No, I don't think that's right, Jacob. "Action at a distance" means instantaneous action. Electromagnetic waves don't fit.

"Field theory" used to mean what you say, but I think today it connotes a "field" that takes time to travel ... as in "quantum field theory." I don't think a distinction is made between particles or waves; the key distinction is between instantaneous action versus action at the speed of light.--Andy Schlafly 21:43, 15 November 2009 (EST)

We'll have to agree to disagree. JacobB 21:44, 15 November 2009 (EST)