@parados,
Quote: So, you are arguing that before Einstein published his theory of relativity we already knew that clocks slowed down when they moved faster.
Yeah, Lorentz formulated the math, about 15 years before Al used it in his theory. But again, the math didn't jump up, from out of nowhere, and tell anybody anything. Math doesn't talk, or predict.
The math was developed to put the predictions in a precise form.
The Lorentz equations "say" the moving clock will slow down. Because that's what the theory predicts. But the equations do not, and cannot, tell you which one (as between a clock on a moving train and one on the ground) will run slower (i.e., which one is moving faster).
Ultimately, empirical experiment has to make that determination. In the case of time dilation, it has been shown that the train clock slows down, not the earth clock. Therefore, it is the train clock which is (or was) moving. As if we didn't already know....