As I understand it, the principle of relativity was accepted from Galileo until Maxwell, whereupon the equations which predict constant speed of light imply a preferred reference frame in a Euclidian space, suddenly making relativity testable.
The Michelson–Morley experiment showed that light speed was constant in all reference frames, ergo Maxwell, relativity, or Euclidian space had to be wrong.
As it turns out Euclidian space is what broke, and moving the equations of physics to Minkowski space allowed us to preserve constant light speed and the principle of relativity (although relativity implies some surprising things in Minkowski space, nevertheless it's merely a logical consequence of the geometry).
Suppose we changed something else instead?
Would physics still make sense if the Michaelson-Morley experiment had shown that light speed was not constant in all reference frames?
- i.e. would everything else still be logically consistent, perhaps with some tweaks, and hence the universe would have a sense of absolute space and time? What would be the consequences of this?
I guess another model universe could have no preferred reference frame but that would imply non-constant lightspeed. Is this a logically consistent hypothetical physics?
- I imagine that would imply a change in the assumptions underlying Maxwell's equations, but my physics isn't good enough to follow this line of reasoning through. What would we have to adjust to make this work, or is it nonsense?