Chuang Tzu and his friend were walking along a river bank and stopped for a moment to gaze at the water.

Chuang Tzu exclaimed, “Look at those fish, how they’re enjoying themselves!”

“How would you know? You aren’t a fish to know if they’re having a good time!” snorted the friend.

“You aren’t me either,”said Chuang Tzu. “So how would you know that I don’t know the fish are having fun?”