Yin and yang of the observation. The yin yang (i.e. taijitu symbol) shows a balance between two opposites with a portion of the opposite element in each section. In Taoist metaphysics, distinctions between good and bad, along with other dichotomous moral judgments, are perceptual, not real; so, the duality of yin and yang is an indivisible whole. In the ethics of Confucianism on the other hand, most notably in the philosophy of Dong Zhongshu ( 2nd century BC), a moral dimension is attached to the idea of yin and yang. These Chinese terms "yin" 陰 or 阴 "shady side" and "yang" 陽 or
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"