It is practically experienced. I know that the ghost, if you go in a house ghostly haunted, if you chant Hare Kṛṣṇa mantra, they'll go away. They cannot tolerate. In my life there was several incidences like that. In my household life, I was doing business in Lucknow. So there was one house, very big house, worth thousands of rupees' rent, but it was ghostly haunted. So nobody would take that house. I took it at two hundred rupees, (laughter) and very big house. And I was... All the servants, they complained, "Sir, there is ghost." So I was chanting. He was living in several spots, especially on the gate side. So I could understand, but I would chant Hare Kṛṣṇa, and I was saved. Everyone was saved.
There was... And, say, in 1969 I was guest in the house of John Lennon in London. So there was a ghost in... It was a big plot. There was a guest house. So they complained, "Sir, here is ghost." So I advised them to chant Hare Kṛṣṇa, and the ghost went away. Yes. This is fact. When there is Hare Kṛṣṇa chanting, these ghostly, demonic living entities, they'll not be able to stay there. They'll go away.
- Bhāgavad-gita Lecture 16.7: Hawaii 3 Feb 1975