Dualistic cosmology Confucianism, beliefs that divide the universe into the complementary oppositions of yin and yang. In traditions such as classical Hinduism, Zen Buddhism or Islamic Sufism, a key to enlightenment is "transcending" this sort of dualistic thinking, without merely substituting dualism with monism or pluralism. The opposition and combination of the universe's two basic principles of yin and yang is a large part of Chinese philosophy, and is an important feature of Taoism, both as a philosophy and as a religion, although the concept developed much earlier. Some argue that yin and yang were originally an earth and sky god, respectively.
Yin and yang "to shelter; shade", and 陽 or 阳 "sunny" is always pronounced with rising second tone "yáng". Sinologists and historical linguists have reconstructed Middle Chinese pronunciations from data in the (7th century CE) "Qieyun" rhyme dictionary and later rhyme tables, which was subsequently used to reconstruct Old Chinese phonology from rhymes in the (11th-7th centuries BCE) "Shijing" and phonological components of Chinese characters. Reconstructions of Old Chinese have illuminated the etymology of modern Chinese words. Compare these Middle Chinese and Old Chinese (with asterisk) reconstructions of "yīn" 陰 and "yáng" 陽: Schuessler gives probable Sino-Tibetan etymologies for both Chinese words. "Yin"