ch’eng Chinese term meaning ‘sincerity’. It means much more than just a psychological attitude. Mencius barely touched upon the subject; it was in the Confucian Doctrine of the Mean that the idea was greatly elaborated. The ultimate metaphysical principle is characterized by ch’eng, as it is true, real, totally beyond illusion and delusion. According to the classic, sincerity is the Way of Heaven; to think how to be sincere is the Way of man; and only those who can be absolutely sincere can fully develop their nature, after which they can assist in the transforming and nourishing process of Heaven and Earth. See also MENCIU. S.-H.L. Ch’eng Hao (1032–85), Ch’eng Yi (1033–1107), Chinese philosophers, brothers who established mature Neo-Confucianism. They elevated the notion of li (pattern) to preeminence and systematically linked their metaphysics to central ethical notions, e.g. hsing (nature) and hsin (heart/mind). Ch’eng Hao was more mystical and a stronger intuitionist. He emphasized a universal, creative spirit of life, jen (benevolence), which permeates all things, just as ch’i (ether/vital force) permeates one’s body, and likened an ‘unfeeling’ (i.e., unbenevolent) person to an ‘unfeeling’ (i.e., paralyzed) person. Both fail to realize a unifying ‘oneness.’ Ch’eng Yi presented a more detailed and developed philosophical system in which the li (pattern) in the mind was awakened by perceiving the li in the world, particularly as revealed in the classics, and by t’ui (extending/inferring) their interconnections. If one studies with ching (reverential attentiveness), one can gain both cognitively accurate and affectively appropriate ‘real knowledge,’ which Ch’eng Yi illustrates with an allegory about those who ‘know’ (i.e., have heard that) tigers are dangerous and those who ‘know’ because they have been mauled. The two brothers differ most in their views on self-cultivation. For Ch’eng Hao, it is more an inner affair: setting oneself right by bringing into full play one’s moral intuition. For Ch’eng Yi, self-cultivation was more external: chih chih (extending knowledge) through ko wu (investigating things). Here lie the beginnings of the major schools of Neo-Confucianism: the Lu–Wang and Ch’eng–Chu schools. See also LI1, NEO-CONFUCIANIS. P.J.I.