"The Way that can be told of is not an unvarying way; The names that can be named are not unvarying names. It was from the Nameless that Heaven and Earth sprang; The named is but the mother that rears the ten thousand creatures, each after its kind." These are the first lines of the Tao Te Ching. Although the book never specifically defines what the Tao is, these lines explain that the Tao is the nameless source of everything; everything comes from and returns to the Tao. It is the underlying law of the universe. It is unfathomable and transcends language.
"The Valley Spirit never dies; It is named the Mysterious Female. And the doorway of the Mysterious Female; Is the base from which Heaven and Earth sprang." (Tao Te Ching, Lao Tzu.) Thai Exotic Treasures.com explains that the Tao Te Ching advocates mostly feminine -- yin -- values and challenges male, or yang, values. It emphasizes the passive quiescence of nature, such as the flowing softness of water, rather than the solid stability of the mountain. Strength and stability are seen as male characteristics. However, yin must be complemented by yang, as these two forces of the Tao should always be balanced and constantly interacting.
"When he is born, man is soft and weak, in death he becomes stiff and hard. The ten thousand creatures and all plants and trees while they are alive are supple and soft, but when dead they become brittle and dry." (Tao Te Ching, Lao Tzu.) This is the theme of eternal return -- of returning to the beginning, or one's own childhood. The comparison here is of the attribute of weakness in life for the newborn baby, and the rigidity of death for the old man. When beings are at their beginning and not yet developed, everything is possible. Therefore a return to one's childhood, or beginning, is required. The idea of "return" here, is not to find your inner self, but emptiness.
"We pierce doors and windows to make a house; And it is on these spaces where there is nothing that the usefulness of the house depends. Therefore just as we take advantage of what is, we should recognize the usefulness of what is not." (Tao Te Ching, Lao Tzu.) Emptiness can mean having no fixed preconceptions, preferences, intentions, or agenda. Emptiness in a person, according to Thai Exotic Treasure.com, means having no heart of his own. This is an approach where letting things happen by themselves is the best way for them to grow, so a wise leader may say that if he does not act, the people will take care of themselves.