By means of sorting out the reference materials concerning the impact of the theories of Cheng and Chu which are found in Mencius: Explorations in Words and Meaning, this paper attempts to explore how Tai Chen deals with the issues of human nature, the way, and multitude. In addition, the author has also managed to compare the works composed by Mencius and Tai Chen with a view to pointing out how their opinions differ on the mentioned aspects. The study foci are placed on Tai Chen's positive view on natural endowment and his endeavor to define fellow feeling and human affairs as vital elements in the process of forming multitude. He thinks that to relieve the lower class of harm done by the upper class and establish equal human relations, people should pay full attention to and engage earnestly in daily affairs. This opinion of Tai Chen, however, has put excessive emphasis on the reciprocity of all individuals as well as the objectivity and infallibility of intrinsic affairs. As a result, Tai Chen is theoretically constrained and unable to achieve the human relationships valued by Mencius, which is based on the core of human nature. The concept of manifesting human relations in daily use is still a principle of general affairs classified by human relations, and thus placing much more emphasis on affairs rather than human relations. This kind of ethics, which is built on affairs, is not intrinsic ethics originating in human nature; it can neither enable people to achieve transcendence of moral quality nor to deal with each other in authentic human ways. In elaborating this principle, Tai Chen has realized the importance of mutual respect and assistance in helping avoid negative impact on the ruled caused by the ruler, but his thoughts on how to lead people to virtue have yet to be perfected.