Before you say I'm wrong consider this, Einstein is supposedly the first person to get completely get rid of the various aether models that were proposed. But didn't Einstein actually prove them right in the sense that things move through a medium called time (i.e. Minkowski space). After all we can measure it just like any other physical thing. It might not be considered spacial but that seems pretty arbitrary because we are defining from our perspective. Am I just splitting hairs? Is this not true?
I'm obviously not a physicist but I'm reading Feynmans Lectures to get a general idea of things (I'm not on the special or general relativity parts yet) but I'm just trying to get a bit of intuition.
Answer
It's important to state exactly what one means by "aether" when saying that aether theories are discredited.
Specifically, the notion of medium that one can in principle detect one's motion relative to is what has been ruled out by experiment. Mediums such as water for acoustic waves fall into this category: the acoustic wave equation changes its form when one is in uniform motion relative to the medium. In contrast, Maxwell's equations do not change their form in this way.
All experiments so far support Galileo's relativity principle - that there is no experiment that one could do making measurements within one's own laboratory that could detect the uniform motion of the laboratory relative to another frame. To understand more deeply exactly what Galileo means here, see the allegory of Salviati's Ship. Most of the 19th century notions of an aether tell against this principle because, as for the motion relative to the water, they would give us an easy way to tell whether we were moving relative to the medium.
However, an aether fulfilling Galileo's principle is not ruled out experimentally. Indeed there was one aether theory, namely Lorentz Aether Theory which is identical in its experimental predictions to special relativity. User ACuriousMind summarizes this theory, and why SR is preferred, in his answer here.
General Relativity brings home the notion that "empty space" is not a void vividly and in a very in-your-face way: in GR "empty space" has definite properties[1] that differ from place to place: for example: its geometry - and outcomes of experiments to detect this geometry - can vary with a nonconstant curvature tensor. Modern quantum field theory goes further: empty space is a real, "material" entity, and modern physics conceives of it as being made of quantum fields in their ground state: modern physics has no need for an extraneous and mind bending notion of "empty space" further to the quantum fields that make up reality.
So, although one must be careful with the word aether to exclude anything that violates Galileo's principle and yields Lorentz-invariant predictions as being in conflict with experiment, I personally kind of like the word as a metaphor for empty space to emphasize the 20th century achievements of general relativity and quantum field theory. We can describe how empty space takes different geometry through the Einstein field equations. The quest for quantum gravity can be thought of as seeking to understand the mechanisms and that machinery of empty space that lead to the EFE description: quantum gravity can be thought of as the quest to find out how the Lorentz-invariant "aether" works.
[1]. It's important to note that even in Newtonian physics "empty space" has definite properties so that, from a philosophical standpoint, the distinction between void and empty space is still very real here, but subtler.
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