It is hard to correct people who know for certain but there are ways to do it by push or by pull, from outside or from inside; to challenge peoples' certitudes push against them to stop them; or grow them until they burst into paradox. This reminds me of a story:
As he grabbed the fakir by the neck he shouted:
“What do you think you are doing here sheikh?”
“Nothing wrong, answered the Sufi with insolent confidence. I am Allah’s loving servant, feeding on the fruit of God’s tree in Allah’s garden.”
“Is that so!”, growled the Hodja and proceeded to beat him with no pity but with a solid wooden stick instead.
“Infidel! screamed the dervish, how do you dare rising your hand upon a saint? Don’t you see what you are doing?”
“Nothing wrong, replied the Hodja. Just hitting the servant of Allah, with the stick of Allah, under the tree of Allah, to preserve Allah’s garden.”
Hearing this, the dervish found enlightenment.