Repealing the Speed Limit?
The pessimism of the left frame is based on the speed limit set by light. Why can't we expect that some future,
much more advanced technology will be able to repeal that speed limit? We cannot rule out that possibility, but
what we can say is that faster-than-light travel is inconsistent with the theory of relativity.
Thus, if
faster-than-light travel is possible, we must reject our best current theory of the structure of spacetime, which
has passed all experimental tests to date, and replace it with something that retains all its correct predictions
while allowing the light barrier to be passed. We cannot conceive today of what such a theory would be.