As translated by Lin Yutang
Once upon a time, I, Chuang Chou, dreamt I was a butterfly, fluttering hither and thither, a veritable butterfly, enjoying itself to the full of its bent, and not knowing it was Chuang Chou. Suddenly I awoke, and came to myself, the veritable Chuang Chou. Now I do not know whether it was then I dreamt I was a butterfly, or whether I am now a butterfly dreaming I am a man. Between me and the butterfly there must be a difference. This is an instance of transformation.
As translated by James Legge, and quoted in The Three Religions of China: Lectures Delivered at Oxford (1913) by William Edward Soothill, p. 75
Once Zhuang Zhou dreamed he was a butterfly, a fluttering butterfly. What fun he had, doing as he pleased! He did not know he was Zhou. Suddenly he woke up and found himself to be Zhou. He did not know whether Zhou had dreamed he was a butterfly or a butterfly had dreamed he was Zhou. Between Zhou and the butterfly there must be some distinction. This is what is meant by the transformation of things.
One night, Zhuangzi dreamed of being a butterfly — a happy butterfly, showing off and doing things as he pleased, unaware of being Zhuangzi. Suddenly he awoke, drowsily, Zhuangzi again. And he could not tell whether it was Zhuangzi who had dreamt the butterfly or the butterfly dreaming Zhuangzi. But there must be some difference between them! This is called 'the transformation of things'.
Once upon a time, Chuang Chou dreamed that he was a butterfly, a butterfly flitting about happily enjoying himself. He didn’t know that he was Chou. Suddenly he awoke and was palpably Chou. He didn’t know whether he were Chou who had dreamed of being a butterfly, or a butterfly who was dreaming that he was Chou.
Originál: (zh_Hant) 昔者莊周夢為蝴蝶，栩栩然蝴蝶也，自喻適志與，不知周也。俄然覺，則戚戚然周也。不知周之夢為蝴蝶與，蝴蝶之夢為周與？週與蝴蝶則必有分矣。此之謂物化。 (traditional)
Kontext: Once upon a time, I, Chuang Chou, dreamt I was a butterfly, fluttering hither and thither, to all intents and purposes a butterfly. I was conscious only of my happiness as a butterfly, unaware that I was Chou. Soon I awaked, and there I was, veritably myself again. Now I do not know whether I was then a man dreaming I was a butterfly, or whether I am now a butterfly, dreaming I am a man. Between a man and a butterfly there is necessarily a distinction. The transition is called the transformation of material things.