Banesh Hoffmann clearly explains that, "without recourse to contracting lengths, local time, or Lorentz transformations" (as was the case in 1887), the Michelson-Morley experiment proves Newton's variable speed of light, c'=c±v, and disproves the constant (independent of the speed of the emitter) speed of light, c'=c, posited by the ether theory and adopted by Einstein:

Banesh Hoffmann, Relativity and Its Roots, p.92: "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. If it was so obvious, though, why did he need to state it as a principle? Because, having taken from the idea of light waves in the ether the one aspect that he needed, he declared early in his paper, to quote his own words, that "the introduction of a 'luminiferous ether' will prove to be superfluous." https://www.amazon.com/Relativity-It.../dp/0486406768

Wikipedia: Newton's variable speed of light, c'=c ± v, explains the result of the Michelson-Morley experiment:

"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

John Norton: "The Michelson-Morley experiment is fully compatible with an emission theory of light that CONTRADICTS THE LIGHT POSTULATE." http://philsci-archive.pitt.edu/1743/2/Norton.pdf

The above (truthful) texts are rare exceptions. Einsteinians almost universally teach that the Michelson-Morley experiment proved the constancy of the speed of light, c'=c, and disproved Newton's variable speed of light, c'=c±v. Post-truth science par excellence:

Edward Witten on modern physics https://youtu.be/fnzLpyDsn3M?t=77

"The conclusion of the Michelson-Morley experiment was that the speed of light was a constant c in any inertial frame. Why is this result so surprising? First, it invalidates the Galilean coordinate transformation. Note that with the frames as defined in the previous section, if light is travelling in the x' direction in frame O' with velocity c, then its speed in the O frame is, by the Galilean transform, c+v, not c as measured. This invalidates two thousand years of understanding of the nature of time and space. The only comparable discovery is the discovery that the earth isn't flat! The Michelson Morley experiment has inevitably brought about a profound change in our understanding of the world." http://www.berkeleyscience.com/relativity.htm

Ethan Siegel: "The speed of light doesn't change when you boost your light source. Imagine throwing a ball as fast as you can. Depending on what sport you're playing, you might get all the way up to 100 miles per hour (~45 meters/second) using your hand-and-arm alone. Now, imagine you're on a train (or in a plane) moving incredibly quickly: 300 miles per hour (~134 m/s). If you throw the ball from the train, moving in the same direction, how fast does the ball move? You simply add the speeds up: 400 miles per hour, and that's your answer. Now, imagine that instead of throwing a ball, you emit a beam of light instead. Add the speed of the light to the speed of the train... and you get an answer that's completely wrong. Really, you do! This was the central idea of Einstein's theory of special relativity, but it wasn't Einstein who made this experimental discovery; it was Albert Michelson, who's pioneering work in the 1880s demonstrated that this was the case." https://www.forbes.com/sites/startsw...tal-surprises/

Stephen Hawking, A Brief History of Time, Chapter 2: "The special theory of relativity was very successful in explaining that the speed of light appears the same to all observers (as shown by the Michelson-Morley experiment)...." http://www.amazon.com/Brief-History-.../dp/0553380168

Brian Cox, p. 91: "...Maxwell's brilliant synthesis of the experimental results of Faraday and others strongly suggested that the speed of light should be the same for all observers. This conclusion was supported by the experimental result of Michelson and Morley, and taken at face value by Einstein.." http://www.amazon.com/Why-Does-mc2-S.../dp/0306817586

Joe Wolfe: "At this stage, many of my students say things like "The invariance of the speed of light among observers is impossible" or "I can't understand it". Well, it's not impossible. It's even more than possible, it is true. This is something that has been extensively measured, and many refinements to the Michelson and Morley experiment, and complementary experiments have confirmed this invariance to very great precision. As to understanding it, there isn't really much to understand. However surprising and weird it may be, it is the case. It's the law in our universe. The fact of the invariance of c doesn't take much understanding." https://newt.phys.unsw.edu.au/einste...eird_logic.htm

Neil deGrasse Tyson: "Beginning in 1905, investigations into the behavior of light got positively spooky. That year, Einstein published his special theory of relativity, in which he ratcheted up M & M's null result to an audacious level. The speed of light in empty space, he declared, is a universal constant, no matter the speed of the light-emitting source or the speed of the person doing the measuring." https://lightnovelsonl.com/novel-ser...2544/chapter-5

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