Chuang Tzu: Butterfly Dream

Once upon a time, I, Chuang Tzu, dreamt I was a butterfly.  Fluttering here, then there and about, I was conscious only of following my fancies as a butterfly. I had no notion of myself as a person at all, I was aware only of being a butterfly. Suddenly, I stirred, and found myself to be Chuang Tzu.

Now I do not know whether I am Chuang Tzu who dreamt I was a butterfly, or whether I am actually a butterfly now dreaming I am Chuang Tzu! How can one know for certain? Between the two, surely there must be some distinction. This is known as the Transformation of Things.

-Chuang Tzu; chapter 214