From "Zhuangzi's Theory of Everything": "In the past, Zhuang Zhou's dream was a butterfly, lifelike, and the metaphor was harmonious! I don't know, Zhou Ye. If you suddenly feel it, you will suddenly feel it. I wonder if Zhou Zhimeng is a butterfly and? What is the butterfly's dream? There must be differences between Zhou and Butterfly. This is called materialization. "

Zhuang Zhou dreamed of a butterfly, was it a butterfly or me, or was I a butterfly? A dream, until now, I can't tell whether that butterfly is me or me.