  Like Heshanggong, Yan Zun also subscribes to the yin-yang cosmological theory characteristic of Han thought. Unlike Heshanggong’s commentary, however, the Zhigui does not prescribe a program of nourishing one’s qi endowment or actively cultivating “long life.” This does not mean that it rejects the ideal of longevity. On the contrary, it recognizes that the Dao “lives forever and does not die” (8.9b), and that the man of Dao, correspondingly, “enjoys long life” (7.2a). Valuing one’s spirit and vital energy is important, but the Zhigui is concerned that self-cultivation must not violate the principle of “nonaction.” Any effort contrary to what the Laozi has termed “naturalness” (ziran) is counter-productive and doomed to failure.