Late one night at the insane asylum one patient shouted, "I am Napoleon!"
A person in another room said, "How do you know?" The first patient said, "God told me!" Just then, a voice from another room shouted,
Yes, but how do we know that there were three different voices coming from three different rooms? Perchance Napoleon is a ventriloquist and just having us on?
then there is the old joke from the time of the BSE crisis:
A man goes into a restaurant and orders Beef Wellington.
The waiter returns a few minutes later and says,
"I'm sorry sir, the beef Wellington's off - it thinks it's Napoleon."