Because the eternal principle of life, Tao, works silently and apparently without action in the way that spring comes round every year, because Tao does not claim credit for its individual acts and is content to be silent, it becomes the image for the Taoist sage.
The demeanor of the pure person
The pure ones of old slept without dreams, and wakened without worries. They ate with indifference to flavor and drew deep breaths. For true people draw breaths from their heels; the vulgar only from their throats.
The pure ones of old did not know what it was to love life or to hate death. They did not rejoice in birth, nor strive to put off dissolution. Unconcerned they came and unconcerned they went. That was all. They did not forget whence it was they had sprung; neither did they seek to inquire their return thither. Cheerfully they accepted life, waiting patiently for their restoration (the end). This is what is called not to allow the mind to lead one astray from Tao, and not to supplement the natural by human means. Such a one may be called a pure or natural person.
Such people are free in mind and calm in demeanor. Sometimes disconsolate like autumn and sometimes warm like spring, their joys and sorrows are in direct touch with the four seasons, in harmony with all creation, and none know the limit thereof….
The pure ones of old appeared towering of stature and yet could not topple down. They behaved as though wanting in themselves, but without looking up to others. Naturally independent of mind, they were not severe. Living in unconstrained freedom, yet they did not try to show off. They appeared to smile as if pleased, and to move only in natural response to surroundings. Their serenity flowed from the store of goodness within. In social relationships, they kept to their inner character. Broadminded, they appeared great; towering, they seemed beyond control. Continuously abiding, they seemed like doors kept shut; absent-minded, they seemed to forget speech.