One day Zhuangzi and Huizi are strolling on Bridge Hao.

Zhuangzi : "Look how happy the fish are just swimming around in the river."

Huizi :      "How do you know they are happy? You are not a fish."

Zhuangzi: "And you are not me. How do you know I don't know the fish are happy?"

Huizi:      "Of course I'm not you, and I don't know what you think;