莊子 - 齊物論 The Adjustment of Controversies

昔者莊周夢為胡蝶，栩栩然胡蝶也，自喻適志與！不知周也。

俄然覺，則蘧蘧然周也。不知周之夢為胡蝶與，胡蝶之夢為周與？

周與胡蝶，則必有分矣。此之謂物化。



Formerly, I, Zhuang Zhou, dreamt that I was a butterfly, a butterfly flying about, feeling that it was enjoying itself. I did not know that it was Zhou.

Suddenly I awoke, and was myself again, the veritable Zhou. I did not know whether it had formerly been Zhou dreaming that he was a butterfly, or it was now a butterfly dreaming that it was Zhou.

But between Zhou and a butterfly there must be a difference. This is a case of what is called the Transformation of Things.