Yin-Yang in Dao/Taoism. The Daodejing by Laozi. Zhuangzi

The Daodejing, Dao De Jing, or Tao Te Ching, is the fundamental text of Daoism / Taoism. Its authorship is attributed to Laozi (or Lao Tzu, the Old Master), a 6th century BCE sage who was a record-keeper at the Zhou Dynasty's (1046–256 BCE) court. Some make Laozi a contemporary of Confucius (551-479 BCE). Laozi is also written as Laotze, Lao Tzu, Lao Tse, Lao Tu, Lao-Tzu, Lao-Tsu, Laosi, Lao Zi, Laocius, together with other variations.

Many Taoists venerate Laozi as 'Daotsu' the founder of the school of Dao, and as the 'Daode Tianjun' in the trinity of the Three Pure Ones, the three highest gods on Daoism and the pure manifestation of the Dao (Tao), "the Way", and the origins of all sentient beings.

Section 42 of the Daodejing (see below) reads: "The Dao, the Way, produces one, one produces two. The two produce three, and the three produce all things." An interpretation is that the Dao produced One, the Taiji (literally "great pole" otherwise meaning "the Supreme Ultimate", the state of undifferentiated absolute and infinite potentiality); the One, the Taiji produced two, the Yin-Yang; the Yin-Yang together with Chi / Qi, or the life force formed the three that produced all things including life.

The name of the book Dao De Jing comes from the opening words of its two sections, the first in Chapter 1: Dao meaning "the way", and the second in Chapter 38: De meaning "virtue or power". Jing means "canon", "great book", or "classic".

[Tao Te Ching is the old style of romanization. The 20^th century style adopted as the official system by the Chinese Government is Daodejing. As the name consists of three separate words, perhaps it is more accurate to write Dao-de-jing.]

Selections from the Daodejing Translation by Charles Muller at acmuller.net
1.
The Dao, the Way, that can be followed is not the eternal Way.
The name that can be named is not the eternal name.
The nameless is the origin of heaven and earth
While naming is the origin of the myriad things.
Therefore, always desireless, you see the mystery
Ever desiring, you see the manifestations.
These two are the same—
When they appear they are named differently.
This sameness is the mystery,
Mystery within mystery;
The door to all marvels.

42.
The Way (the Dao) produces one, one produces two.
The two produce the three and the three produce all things.
All things submit to yin and embrace yang.
They soften their energy to achieve harmony.

Zhuangzi (369—298 BCE), or "Master Zhuang" (also romanized as Chuang-tzu) was, after Laozi, one of the earliest thinkers to contribute to Daojia, the School of the Way. Regarding Yin-Yang, he writes in Chapter 21 of his book: "Yin in its highest form is freezing while yang in its highest form is boiling. The chilliness comes from heaven while the warmness comes from the earth. The interaction of these two establishes he (harmony), so it gives birth to things. Perhaps this is the law of everything yet there is no form being seen."

Duality & Dualism pages of this blog:
» Bon, Zoroastrianism & Dualism
» Dual, Duality & Dualism. Definitions (New)
» The Two - Ta Mainyu (New)
» Yin-Yang Dualism. Development of the Concept (New)
» Yin-Yang in Daoism / Taoism. The Daodejing by Laozi. Zhuangzi (New)
» Plutarch. His Work, Duality and the Soul (New)