Zhuang Zi

“Once in the past, Zhuang Zhou dreamt that he was a butterfly, flitting and fluttering around, content with himself and doing what he pleased. He didn’t know he was Zhuang Zhou. Suddenly he woke up. There he was, solid and clearly Zhuang Zhou. But he did not know whether, in fact, he was Zhuang Zhou who had dreamt he was a butterfly, or a butterfly now dreaming he was Zhuang Zhou. Between Zhuang Zhou and the butterfly there must be some distinction! These are the different transformations of beings.”
Zhuang Zi Chapter 2