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? However, there must be some sort of difference between Chuang Tzu and a butterfly!
The baby looks at things all day without winking; that is because his eyes are not focused on any particular object. He goes without knowing where he is going, and stops without knowing what he is doing. He merges himself within the surroundings and moves along with it. These are the principles of mental hygiene.