According to the Wei dynastic histories, He Yan enjoyed and had a great insight into the works of the Daoist philosophers
Laozi and
Zhuangzi, and into the
Book of Changes, from an early age. He wrote a famous commentary that was influential in his own time, the
Commentary on the Daode Jing (
Daode Lun), but no copies have survived. He was planning on writing a more detailed, interlinear commentary on the
Daode Jing; but, after comparing his draft with a similar draft by a younger Wang Bi, He decided that his interpretation was inferior, and the
Commentary that he eventually produced was more general and broad. He Yan was a member of a committee that produced an influential and authoritative commentary on
Confucian theory, the
Collected Explanations of the Analects (
Lunyu Jijie), which collected, selected, summarised and rationalised the most insightful of all preceding commentaries on the
Analects that had been written by his time. He produced the commentary as a member of a five-member committee (the other four members of the committee were Sun Yong, Zheng Chong, Cao Xi and Sun Yi), but was given almost sole credit as the principal writer by subsequent Chinese scholars, and by the
Tang dynasty (618-907) He Yan's name was the sole author associated with the
Collected Explanations. Modern scholars are unsure of what evidence led medieval Chinese scholars to believe that He was the sole author, or if he wrote the
Collected Explanations out of interest or because he was ordered to by the Wei court, but continue to credit He Yan as the principal author out of convention. After He Yan presented it to the imperial court, the
Collected Explanations was quickly recognised as authoritative and remained the principal text used by Chinese readers to interpret the
Analects for nearly 1,000 years, until it was displaced by
Zhu Xi's commentary in the 14th century. He Yan believed that
Daoism and
Confucianism complimented each other so that by studying them both in a correct manner a scholar could arrive at a single, unified truth. Arguing for the ultimate compatibility of Daoist and Confucian teachings, He argued that "Laozi [in fact] was in agreement with the Sage" (sic). By promoting the synthesis of Daoist and Confucian concepts, He became a principal advocate of the neo-Daoist school of
Xuanxue (along with his friend and contemporary, Wang Bi). As a scholar of Xuanxue, He was notable for exploring the theory of
wuwei. He was a prolific writer of poetry and wrote numerous miscellaneous essays on philosophy, politics, literature, and history, some of which still survive. ==Notes==