Zhu Xi (1130-1200) was a Song Dynasty (960-1279) Confucian scholar who became one of the most significant Neo-Confucians in China. He taught at the famous White Deer Grotto Academy for some time. During the Song Dynasty, Zhu Xi’s teachings were considered to the orthodoxy. Zhu Xi and his fellow scholars added two additional Chinese classic texts: the Great Learning, and the Doctrine of Mean to the Confucian canon. Their writings were not widely recognized in Zhu Xi’s time; however, they later became accepted as standard commentaries on the Confucian classics.
Zhu Xi considered the earlier philosopher Xun Zi to be a heretic for departing from Confucius’s beliefs about innate human goodness. Zhu Xi contributed to Confucian philosophy by articulating what was to become the orthodox Confucian interpretation of a number of beliefs in Taoism and Buddhism. He adapted some ideas from these competing religions into his form of Confucianism.
He argued that all things are brought into being by two universal elements discussed by Confucius and Mencius: vital (or physical) force (qi), and law or rational principle (li). Li is also called Tai Ji or Tai Chi, which means Great Ultimate. According to Zhu Xi, Tai Ji causes qi movement and change in the physical world, resulting in the division of the world into the two energy modes (yin and yang) and the five elements (fire, water, wood, metal, and earth).
According to Zhu Xi’s theory, every physical object and every person contains aspects of li or Tai Ji. What is referred to as the human soul, mind, or spirit is defined as the Great Ultimate (Tai Ji), or the supreme regulative principle at work in a person. Zhu Xi argued that the fundamental nature of humans was morally good; even if people displayed immoral behavior, the supreme regulative principle was good.
According to Zhu Xi, vital force (qi) and rational principle (li) operated together in mutual dependence. These are not entirely non-physical forces, but resulted in the creation of mater. When their activity is rapid the yang energy mode is generated, and when their activity is slow, the yin energy mode is generated. The yang and yin constantly interact, gaining and losing dominance over the other. This results in the structures of nature known as the five elements.
He did not hold to traditional ideas of God of Heaven (Tian), though he discussed how his own ideas mirrored the traditional concepts. He encouraged an agnostic tendency within Confucianism, because he believed that the Great Ultimate was a rational principle, and discussed it as an intelligent and ordering will behind the universe. He did not promote the worship of spirits and offerings to images. Although he practiced some forms of ancestor worship, he disagreed that the souls of ancestors existed, believing instead that ancestor worship is a form of remembrance and gratitude.