"Special relativity was derived from one experimentally observed fact, that light always travels at the same speed (in a vacuum), which we'll call c, which is about 300,000 kilometres per second. That's always at the same speed relative to you. Even if you're travelling at half the speed of light yourself, light still travels past you at speed c relative to you. This makes no sense. For it to be true, something has to be seriously wrong with our 'normal' understanding of physics. And it is." https://finitismforever.wordpress.com/2017/02/26/354/
That is, for Einstein's nonsense to be true, normality was abandoned - science embraced abnormal space and time where nonsense and truth coincided.
The problem is that "experimentally observed fact" is a blatant lie. The relevant experiment, that of Michelson-Morley, was compatible with the variable speed of light predicted by Newton's emission theory of light and, prior to FitzGerald and Lorentz advancing the ad hoc length contraction hypothesis, incompatible with the constant (independent of the speed of the light source) speed of light predicted by the ether theory and later adopted by Einstein as his 1905 second ("light") postulate:
"To it, we should add that the null result of the Michelson-Morley experiment was unhelpful and possibly counter-productive in Einstein's investigations of an emission theory of light, for the null result is predicted by an emission theory."
"Emission theory, also called emitter theory or ballistic theory of light, was a competing theory for the special theory of relativity, explaining the results of the Michelson–Morley experiment of 1887. [...] The name most often associated with emission theory is Isaac Newton. In his corpuscular theory Newton visualized light "corpuscles" being thrown off from hot bodies at a nominal speed of c with respect to the emitting object, and obeying the usual laws of Newtonian mechanics, and we then expect light to be moving towards us with a speed that is offset by the speed of the distant emitter (c ± v)."
"The Michelson-Morley experiment is fully compatible with an emission theory of light that CONTRADICTS THE LIGHT POSTULATE."