In India, in a village there used to be a pandit, he was famous for chasing the ghosts away. People used to bring those possessed by Ghosts to him, he was a very powerful magician, he would chant some mantra and throw magic powder into the ceremonial fire and get rid of the ghost.

Once people from the next village brought a man possessed by a ghost, that man was laughing and screaming at everyone, the Pandit had never seen a ghost like that, he was surprised, the Pandit looking into that person said "I will teach you a lesson."

The ghost looked into his eyes and last laughed even louder.

The pandit became very angry and started chanting mantras at top of his voice and threw magic powder Into the fire.

The Ghost kept laughing

The pundit tried again and again, but he could not get rid of the ghost, he was very experienced and had always managed to get rid of the ghosts, he was so puzzled that he asked the ghost itself "I have got rid of all the Ghosts my experience, why can't I get rid of you ?"

The ghost laughed and replied back "Before you could chant the Mantra I myself got into that Powder, so you could not use what I already possess against me."

Moral of the story: You should not expect a prejudiced mind to reason.

http://aumamen.com/story/rationality-of-a-prejudiced-mind-story-of-a-ghost