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Not_Pictured t1_j9oktkf wrote

Reply to comment by very-based-redditor in What does it mean for light to be an excitation in the electromagnetic field? by Ethan-Wakefield

All of our understanding of physics comes from making up models of reality and seeing how close to reality they match. The model of reality that treats all particles as excitation in fields is part of the single most accurate model humanity has ever come up with.

Is this model a true analogy of reality? Yes? Maybe?. At some level our 'real' understanding of realty turns into a version of "shut up and calculate" or "we don't know". It 'seems' reality is a bunch of rubber sheets stacked on top of each-other. Waves and ripples move through them and the energy from one sheet can transfer into other sheets like as if they touched eachother. Waves in one can 'bump' and create waves in other fields. "Physical things" are again just excitations in one or more of these rubber sheets.

The best answer to "what is a field?" is the definition of a field because that's what the model of reality assumes it is. True or not.

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Implausibilibuddy t1_j9ou88q wrote

> The model of reality that treats all particles as excitation in fields is part of the single most accurate model humanity has ever come up with.

Isn't that just "ether theory" with extra steps?

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agate_ t1_j9pgp8i wrote

It’s “ether theory” that works. We adopt or discard models of the universe based on whether they make accurate predictions, and the ether theory of light didn’t.

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sticklebat t1_j9y2cji wrote

Superficially, kind of? There are many differences though. One is that the ether was proposed in order to provide a rest frame for light, whereas the fields upon which modern physics is based are fully relativistic. Another is that the ether was thought of as a physical thing thing with density, velocity, etc., and whereas fields can’t really be described in those terms, at least not as directly. It’s more that fields can give rise to them.

TL;DR an ether theory is similar to fields in that they permeate all of space, but they’re fundamentally different from each other in properties and mechanics.

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