Once upon a time, I, Chuang Tzu, dreamt that i was a butterfly. flitting around and enjoying myself. I had no idea I was Chuang Tzu.
Then suddenly I woke up and was Chuang Tzu again. But I could not tell, had I been Chuang Tzu dreaming I was a butterfly, or a butterfly dreaming I was now Chuang Tzu?