The "ego" is a major topic of discussion in all religions and philosophies. In the history of Indian religious philosophy, there are two traditions of knowing "self": "atman" and "anatman". The theory of "atman" holds that there exists an eternal and invariable subject of life in the universe-the "ego". On the basis of criticizing the theory of "atman", the Hinayana dharma establishes the theory of "anatman", which holds that the "ego" is composed of various elements, and has no constancy and no substantiality. "Non-self" is not extinction and nothingness, but to purify the mind. "self" takes "non-self" as its essential attribute. In this sense, "no self", as the basis of virtue, has positive enlightenment significance for modern human's self-development.