It does not necessarily allow for a violation of causality.
As an example, suppose that we were able to go faster than C in the reference frame of the fixed distant stars, but not in other reference frames. There are reference frames where you can go backwards in time, but none in which you can violate causality.
(That said, General Relativity allows for causality violations. However setting them up is well beyond any engineering ability our species is likely to develop...)
As an example, suppose that we were able to go faster than C in the reference frame of the fixed distant stars, but not in other reference frames. There are reference frames where you can go backwards in time, but none in which you can violate causality.
(That said, General Relativity allows for causality violations. However setting them up is well beyond any engineering ability our species is likely to develop...)