So I definitely don’t think there is an ether for starters. I am reading electrodynamics by Griffith and he states that Einstein’s second postulate which says “The speed of light in vacuum is the same for all inertial observers, regardless of the motion of the source” disproves the ether. Griffiths then says the principle of relativity is not enough to disprove the ether.
My thought process is that the ether would imply an absolute reference frame which would violate the first postulate but Griffiths claims that is not true. I have been thinking about it a lot and I can’t seem to find a clear argument just from Einsteins two postulates which disproves the ether.
Can anyone give me a clear argument as to how this works? Also in this thought experiment I am not using the wave particle duality of light because then it’d be obvious.
Best Answer
Nothing disproves the ether. Lorentz and Poincaré created a theory, equivalent to special relativity, that incorporated an unobservable ether. But Einstein's approach was simpler and clearer, especially with Minkowski's geometric interpretation, so that's what we use.