In early China, views concerning human nature underwent significant development, with philosophers moving from seeing it as desire or instinct to seeing it as virtue or essence. Before Confucius’s time, human beings’ xing, or nature, was construed as desire and instinct, i.e., as a physical nature. The key problem faced by theorists of human nature at that time was how to manage nature with virtue, i.e., how to use virtue to both control and enrich nature. A later, wide-reaching development was the use of qi to explain human nature. Laozi began, taking de or virtue to be the internal essence of the human being; Confucius took de or virtue to be xing or nature. Following this development, the main current of the theory of human nature in the pre-Qin period divided into two branches. One, created by the later Confucius, inherited in part by Zisi, and developed by Mencius, took virtue as nature and insisted on the a priority of internal morality. The other branch, inherited in part by Zisi and developed by the author of Xing Zi Ming Chu and Xunzi, featured the development of the old tradition which took yu, or desire, as nature.