| > The Atomic Rockets website[0] describes the issue clearly: I don't find their description very clear. In particular, they don't even define - what "faster-than-light" is supposed to mean in a non-relativistic setting (Newtonian mechanics) where there's no such thing as a universal velocity and you're dealing with Galilean velocity transformations. - what causality is supposed to mean exactly outside the relativistic setting where you have a universal velocity which induces the causal structure. All in all, their definitions are very inter-dependent, so the "trichotomy" they present as truth doesn't make much sense to begin with. From my POV, they're not even wrong[0]. Moreover, they seem to only consider Special Relativity and completely ignore General Relativity where the speed-of-light bound is only a local bound. Basically, even if what they say were true, it would still not apply to the General Relativistic setting we're looking at here. > Time travel makes Causality impossible, since it can be used to create paradoxes This is not so clear, either, compare e.g. https://en.wikipedia.org/wiki/Novikov_self-consistency_princ... [0]: https://en.wikipedia.org/wiki/Not_even_wrong |