The fact that the speed of light is constant in space predates Einstein. Michelson and Morley determined this by experimentation in 1887.
The report to their sponsor, A. Graham Bell, indicates the results were inconclusive.
My argument was actually about darwinian materialism to the person I posted to. I have tried to point out that there have been many studies which concentrate on validating, expanding, and tidying the dominant paradigm.
Gradually though anomalies, discrepancies, and contradictions begin to accumulate. The paradigm breaks down; another takes its place in a "paradigm shift." The process begins again. The Earth is the center of the universe. The sun is the center of the universe. The universe has no center. And on and on.
Of the great thinkers who fashioned the modern worldview, only one--Charles Darwin--remains inviolable. Sorry for hijacking the thread...