although i love twain i have to agree. merely standing by your convictions is not enough to ensure a sane and civil society. its only at the last point where twain mentions truth that i really agree with him.
the true responsibility of a member of any community, whether it is organized as a republic, monarchy, whatever...is to attempt to gain some insight into truth.
truth can be thought of as the correspondence of ideas with objective reality. people may believe something is true without having ever put their beliefs to the full scrutiny of reason.