[N0B0DY]

I agree that credentials are important, RP, but textbooks and experiments are open to interpretations that set the foundation for future textbooks and experiments. So in that light, I suggest there is a difference between the optical illusion of group velocities greatly exceeding or slowing light and the absolute speed of light.

The correlation between mass and energy can be taken, as well as mistaken, as variable forms of matter. Yet, even in such an interpretive case, matter - which I liken to the absolute speed of light/aether/space - never changes.