A man is in a mental hospital because he believes himself to be a seed.
He is treated for years by one of the world’s best psychiatrists. After 6 years, he finally becomes convinced that he is not, in fact, a seed. There is a party to celebrate his release from the hospital.
A chicken shows up to the party. The man freezes and slowly starts to inch behind a nearby tree. His psychiatrist notices and sighs: “I thought you were over this. You are not a seed, remember?”
The man replies: “look, you know that I am not a seed. I know that I am not a seed. But does the chicken know?”