The Taoist teacher Chuang Tzu was walking with a friend over a bridge. Chuang Tzu saw some fish darting about and said, “That is happiness for a fish.”
His friend said, “You’re not a fish! How do you know what makes a fish happy?”
Chuang Tzu responded, “You’re not me! How do you know I don’t know what makes a fish happy?”
What was Chuang Tzu saying to his friend?