Of late years, some scholars of the Tien-tai school have regarded the idea of vice as one of the characteristics of the school. In The Significance of Kuangyin `sutra` the idea of vice is clearly stated，and quite a few words are written to explain it. Therefore，based on this fact some scholars speak and write in support of the theory that the Tien-tai school is characteristic of the idea of vice. In fact，they do not understand what the idea of vice really means, arbitrarily considering the vice to be the central idea of the Tien-tai school. And there are still some others who are confident that the vice is born by nature.
However，in accordance with the studies by the author，the idea of vice in The Significance of Kuangyin `Sutra` comes from the idea of environing cause and revealing cause. It is a special way for all the flesh of gradual attainment of the Tien-tai five divisions, leading the flesh to the Buddha-nature of non-environment and non-causation. This is the very purpose of virtue and vice, different from what recent scholars understand. For instance，recent scholars try to understand the virtue and vice of developing cause in. The Significance of Kuangyin `Sutra`，through the originality of all dharmas. Thus, the idea of vice becomes the inevitability of nature-possession... nature itself is possessed of all dharmas and inevitably is inclusive of vice. Those who are of this opinion believe that the Tien-tai thought is of nature-possession，and must lead to the idea of vice，which forms one of its features. If we look at such a problem from the standpoints of conditional causation，the mean，and reality--the teachings of the Tien-tai school，we are easy to find that the nature-possession and the idea of vice are contradictory to each other.
Yet，in The Significance of Kuangyin `Sutra` some ideas are stated not so well that they raise some difficulities to the theory of reality.
In order to solve the problems mentioned above，the following chapters intend to make a study of the structure and system of The Significance of Kuangyin `Sutra`，then to have an understanding of the virtue and vice in developing cause，and finally to take a look at the vice problem through the Tien-tai conditional causation，the mean，and reality.