Dreaming....are you still dreaming? (Zen)

The great Taoist master Chuang Tzu once dreamt that he was a butterfly fluttering here and there. In the dream he had no awareness of his individuality as a person. He was only a butterfly. Suddenly, he awoke and found himself laying there, a person once again. But then he thought to himself, "Was I before a man who dreamt about being a butterfly, or am I now a butterfly who dreams about being a man?"