"Once upon a time Chuang Tzu dreamt he was a butterfly - a butterfly flitting and fluttering around, happy with himself and doing as he pleased. He didn't know he was Chuang Tzu. Suddenly he woke up and there he was, solid and unmistakable Chuang Tzu. But he didn't know anymore if he was Chuang Tzu who had dreamt he was a butterfly, or a butterfly dreaming he was Chuang Tzu."