Physics is desperately post-truth. Consider the following two questions:
Question 1: In 1887, was the Michelson-Morley experiment compatible with Newton's variable speed of light, c'=c±v (the speed of light depends on v, the speed of the emitter relative to the observer)?
Question 2: In 1887, was the Michelson-Morley experiment compatible with the constant speed of light, c'=c (the speed of light is independent of v, the speed of the emitter relative to the observer)?
The following two quotations clearly show that the answer to Question 1 is "yes". Given that, the answer to Question 2 is almost obviously "no". And here a post-truth principle can be clearly seen: The more obvious the truth is, the more persistently it is ignored. By everybody, not just relativists. Anti-relativists attack Einstein but try to replace his fiction with some other fiction, never the truth.
"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
"Moreover, if light consists of particles, as Einstein had suggested in his paper submitted just thirteen weeks before this one, the second principle seems absurd: A stone thrown from a speeding train can do far more damage than one thrown from a train at rest; the speed of the particle is not independent of the motion of the object emitting it. And if we take light to consist of particles and assume that these particles obey Newton's laws, they will conform to Newtonian relativity and thus automatically account for the null result of the Michelson-Morley experiment without recourse to contracting lengths, local time, or Lorentz transformations. Yet, as we have seen, Einstein resisted the temptation to account for the null result in terms of particles of light and simple, familiar Newtonian ideas, and introduced as his second postulate something that was more or less obvious when thought of in terms of waves in an ether." Banesh Hoffmann, Relativity and Its Roots, p.92 https://www.amazon.com/Relativity-Its-Roots-Banesh-Hoffmann/dp/0486406768
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