The Impossible Question?

"Once upon a time, I, Chuang Tzu, dreamed I was a butterfly, fluttering hither and thither, to all intents and purposes a butterfly, and was unconscious of my individuality as a man. Suddenly I awoke, and there I lay, 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."