So we have thesis and antithesis, and no experiment can be compatible with both of them (unless the experiment is incorrect):
Statement 1: Speed of light varies with speed of the source.
Statement 2: Speed of light is independent of speed of the source.
In 1887 the Michelson-Morley experiment was compatible with Statement 1 - accordingly, since the experiment was correct, it could not be compatible with Statement 2:
"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)."
https://en.wikipedia.org/wiki/Emission_theory
After Lorentz and FitzGerald introduced their idiotic ad hoc assumptions, the Michelson-Morley experiment became compatible with Statement 2. Accordingly, since the experiment was still correct, it was now incompatible with Statement 1.
Again: Compatibility with both Statement 1 and Statement 2 (thesis and antithesis) is impossible unless the experiment is incorrect.
Pentcho Valev