Chang Êr-ch'i 張爾岐 (T. 稷若 H. 蒿庵), Aug. 18, 1612-1678, Jan. 20, philosopher and commentator, was born in Chi-yang, Shantung. His ancestors, at the beginning of the Ming period, emigrated from Tsao-ch'iang, Hopei, into Shantung, and were farmers for generations. With his grandfather, Chang Lan 張蘭 (T. 汝馨 H. 前川, 1539-1618), literary interests began to appear in the family. His father, Chang Hsing-su 張行素 (T. 龍溪, 1582-1639), occupied the unimportant position of an inspector of a post-station, his honesty closing to him the way to higher offices. When his father met death at the hands of soldiers, only the duty of caring for his aged mother prevented Chang Êr-ch'i from taking his own life. Even so, he spent his entire life in seclusion. When summoned to participate in the po-hsüeh hung-tz'ŭ examination of 1679 he declined on the plea of illness.
The literary labors of Chang Êr-ch'i were primarily dedicated to ceremonies and rituals. His commentary to the Decorum Ritual, entitled I-li Chūūng-chu chü-tou, in 17  chüan, first printed in 1743, and incorporated in the Shih-san ching chu-shu (see under Juan Yüan), ranks even today as one of the best treatments of that classic. Further, he wrote paraphrases to the Book of Changes, entitled 周易說略 Chou-i shuo-lüeh, in 8 chüan, first printed in 1719; to the Odes, entitled Shih-ching (詩經) shuo-lüeh, in 5 chüan, and to the Tao-tūcirc;<> ching, entitled Lao-tzŭ (老子) shuo-lüeh, in 2 chüan. He also wrote commentaries to the 夏小正 Hsia hsiao-chūūng, in the 法戴禮記 Ta-Tai Li-chi, entitled Hsia hsiao-chūūng chuan-chu (傳註), in 1 chüan, and to the chapter 弟子職 Ti-tzŭ<> chih in 管子 Kuan-tzŭ, entitled Ti-tzcirc;<> chih chu (註), in 1 chüan. A gazetteer attributed to him, entitled 濟陽縣志 Chi-yang hsien-chih, in 9 chüan, is apparently no longer extant. His later years he devoted to a work on the Spring and Autumn Annals, entitled 春秋傳議 Ch'un-ch'iu chuan-i, in 4 chüan, which he was not able to finish. Aside from these works, there have been handed down by him two collections: 蒿庵閒話 Hao-an hsien-hua, 2 chüan, completed in 1670 and published in various ts'ung-shu ; and Hao-an chi (集), 3 chüan, printed in 1773. The former contains diary-like notes in many fields of knowledge; the latter is a compilation of his philosophical treatises, prefaces and miscellaneous essays.
In contrast to Sun Ch'i-fūūng [q.v.], and other scholars of his time, Chang Êr-ch'i's philological and philosophical writings reveal a clear reaction against the tradition of Wang Shou-jūūn (王守仁, 1472-1529) and an affiliation with the School of Han Learning (see under Ku Yen-wu). Among the Han scholars he feels a kinship primarily with Chūūng Hsüan 鄭玄 (T. 康成, 127-200), whom he follows, particularly in the renewed emphasis on ceremonies and on their metaphysical implications. In the same way his philosophy in general is deeply rooted in metaphysical considerations. Thus his friend Ku Yen-wu is filled with admiration because of his familiarity with the details in ceremonies and rituals; and with astonishment because, in an interchange of letters Chang points out the ultimate grounds in contrast to Ku's seemingly one-sided emphasis on science and ethics. For Chang Êr-ch'i, science and ethics are of value only when they clearly reveal their metaphysical meaning. One therefore need not wonder why, in addition to the I-ching, he regards the book of Lao-tzcirc;<> as worthy of a paraphrase, or that in his smaller treatises he occasionally even strikes a Buddhistic note. His philosophical ideas have been preserved mainly in his treatises on the Chung-yung, (中庸論 Chung-yung lun ; on the Way of Heaven, 天道論 T'ien-tao lun); on knowledge, 學辨 Hsüeh pien); and in other writings unfortunately preserved only in fragments. The Chung-yung lun offers a sharp rebuke to those who through piratical utilization of Chung-yung citations seek to conceal their superficial conduct; and though face to face with the arguments of the Chung-yung, hold morals to be superfluous ornamentation. He expostulates with these that morals are the sole medium through which Tao 道 can be actualized, and that the metaphysical foundation of morals in the Chung-yung may not be understood until one has grasped the practical significance of morals. In the T'ien-tao lun he uses this classic against the romantic individualism of Wang Shou-jūūn denying at the same time the validity of agnosticism. In a train of ideas which follow closely the Neo-Confucian scholasticism (理學) of the Sung period, he portrays in the first section the channels which connect the Heavenly Way (天道) with its earthly effects and so create fate. He shows also how a wealth or a dearth of ch'i 氣 affects the situation, and how good or bad deeds, words, and thoughts accumulate (積) to alter circumstances (勢). In the second section he analyzes with sovereign power and humor the triviality of the psychological motives which may lead to agnosticism. The Hsüeh pien, comprising five sections, finally may be said to present a new foundation for the decaying sciences. Unfortunately only the first section, dealing with the scientific ethos (志) has been preserved — a castigation of the will-to-gain as the source of all confusion and corruption.
Chang Êr-ch'i, never advanced politically. He shared, however, as his poem, 杜宇 Tu-yü, indicates, the irreconcilable attitude of his contemporaries against the new dynasty, and was suspicious of those of his colleagues who willingly took office under it. With the exception of the apparently accidental encounter with Ku Yen-wu, his name never, during his life time, penetrated beyond the borders of his district. He lived always in poverty and want and had alternately to push the plow and wield the brush. Not until the Ch'ien-lung period (late in 1776) were, through the efforts of Lu Yüeh 陸燿 (T. 朗夫 H. 青來, 1723-1785) an ancestral ball (祠堂) and an Academy (書院) established as memorials to him.
[ 1/487/3b; 2/68/6b; 3/399/1a; 4/130/6a; 7/27/21b; 13/1/13b; 16/3/16a; 17/2/19b; Chi-yang hsien-  chih, (1765), preface and 8/4a, 13/42a, 13/45b; Hao-an chi preface and 3/28a, 28b, 29a.]