Abstract
The main theme of Neo-Confucianism is about Tian-Dao (天道) and Xing-Ming (性命). Tian-Dao is a term of meta- physics, while Xing-Ming is a term of the mind-nature theory (心性论) and is more radical than the former. The Neo-Confucians thought their source of the mind-nature theory was Mencius, and they had both documental and philosophical reasons for this assertion. But I think the Neo-Confucians had transformed the meaning of Mencius when they thought they had acquired the validity from this book. In this article, I will center on Mencius' two crucial concepts-”goodness of nature” (性善) and Liang-Zhi (良知), and show that these words which the Neo-Confucians expanded metaphysically so as to make connection between Tian-Dao and Xing-Ming were simply terms of the mind-nature theory initially. This transformation could be seen as a manifestation of the implications of the words, and a leap that went far beyond their original meanings.