While I personally cannot concieve of any realistic theory of propulsion that will allow us to achieve FTL travel, (heck I personally can't concieve of the theory of relativity and quontum mechanics, and those have been demonstrated in experiments.
) I hope that as a species we don't give up dreaming about it trying to discover ways to do it.
It would be as if we became so convinced that the earth was flat that we don't bother to send sailing ships beyond the horizon.