One day Chuang-tzu and a friend
were walking along a riverbank.

"How delightfully the fishes are
enjoying themselves in the water!"
Chuang-tzu exclaimed.

"You are not a fish," his friend said.
"How do you know whether or not
the fishes are enjoying themselves?"

"You are not me," Chuang-tzu said.
"How do you know that I do not know
that the fishes are enjoying themselves?"