The Limit of the Speed of Light

We say the speed of light is constant for all observers. It doesn't depend on who is sending the message or their velocity, is always the same speed. All special relativity is based on that one observation. And so that's what limits you to going faster than the speed oflight. If we observed a scenario in which that wasn't true any more, then maybe you would change all these other rules. Or maybe that's wrong, and we just don't understand. We make an observation here, we infer about the universe. From it, we draw conclusions. If those conclusions are wrong, either our inference was wrong or the observations we made were wrong.