[ben_w]

That’s something I’ve been meaning to ask about:

Does FTL really inevitably mean that, or is that a consequence of saying “no preferred frame of reference” and therefore having e.g. “100c” meaning different things to observers in relative motion?

[crooked-v]

"No preferred frame of reference" is how the universe fundamentally works - if you remove that, you're looking at a universe that functions differently than our own in a lot of basic ways.

[ben_w]

Follow up question: while no preferred frame is obviously the simplest model, is it really impossible to add a preferred frame? e.g. https://youtu.be/6MfJ59lkABY?t=413

[QuadmasterXLII]

You are correct, it requires “no preferred frame of reference”.