Among the ideas facing revision is Einstein's belief that the speed of light must always be the same - 186,000 miles a second in a vacuum. There is growing evidence that light moved much faster during the early stages of our universe.This doesn't bother me. In the very early universe, light could have moved faster. That's virtually implied by cosmological inflation. As long as no causality violations are involved, I see no problems. Now, of course, there are definite problems if we start traveling or communicating faster than light. But initially, photons moving out to the horizon faster than c, that's no big deal, theoretically. Or am I missing something?
I believe it does pose a problem, in that our method of "divining" the properties of the Big Bang is by projecting backwards in time the currently expanding Universe and applying the Theory General Relativity to see what the conditions must have been in earlier stages of the Universe's evolution. It seems to me that one cannot hold the belief that General Relativity is valid all the way back to the BB AND concurrently believe that at some earlier time in the history of the Universe light traveled at a speed >c, as the constancy of the speed of light is an assumption which underlies Special Relativity, which is nothing more than General Relativity in the absence gravity.
In other words, it seems to me that this would constitute asserting that Relativity was both true and NOT true at some point in the history of the Universe. This seems untenable, but perhaps there's more to the story that I don't understand.