We learn more about how human brains work. And that leads us to ideas about how to make human brains work better.
More philosophically-minded critics regarded Einstein's argument for relativity as little more than a logical bait-and-switch ploy: "[T]he supposition of most expounders of the Special Theory, that Einstein has proved the relativity of simultaneity in general - or that his 'simultaneity' is something more than a logical artefact - must manifestly be given up.