Members of the heaven's gate cult, who "knew" there was a spaceship following the hale-bopp comet, returned a perfectly good telescope they had purchased because they failed to see the spaceship they "knew" was there. such behaviors demonstrate that

People will often go off the limits to justify their beliefs.

Explanation:

Members of the Heaven's Gate cult assumed that there was  a spaceship following the Hale-Bopp comet without any research. Even the spaceship was not be seen with the telescopes. So the members of the Heaven's Gate returned the telescope despite they didn't has any defects on the fact that they believed that there was a spaceship.

answer; disconfirm the catharsis theory;