In 1887, Michaelson & Morley did their famous interferometer experiment, which demonstrated there was no such thing as the luminiferous aether. Which, fine. The idea that there's a stationary substance through which everything transits seems a little absurd.

But things like entanglement and vacuum energy seem to suggest that there IS some kind of connection between atoms. So if the connections between the atoms and the atoms themselves are made of the same thing, how could you possibly detect it?