Abstract: The concept of the theory on "zhi" comes from Zhang Dainian, which generally refers to ancient thinkers' theories about "zhi", aiming to distinguish them from epistemology. Zhang Zai and the two Cheng brothers are the core figures of the school of Guan and the school of Luo respectively. They payed more attentions to "zhi" than their predecessors. Their theories on "zhi" mainly involve the discrimination and mechanism of "zhi", the reasons why "zhi" can't be extended, and how to extend "zhi".

In the aspect of discrimination of "zhi", Zhang Zai has formed a conceptual system of three levels and two groups of concepts, namely, the innate knowledge and the knowledge of what is heard or what is seen, and the knowledge gained through enlightenment and the small knowledge of what is heard or what is seen. The criteria of the division are: whether "zhi" is innate, and whether it is from the work of the moral heart. Cheng Hao interprets the innate knowledge by inherent things and ren, and distinguishes concrete knowledge by virtue and learning, concentrating on the essentials and erudition. Cheng Yi also discusses the concepts of the knowledge of virtue and the knowledge of what is heard or what is seen, which are equivalent to Zhang's the innate knowledge and the small knowledge of what is heard or what is seen. Moreover, he distinguishes concrete knowledge by concepts like deep knowledge and shallow knowledge, real knowledge and knowledge just from hearing or seeing. In the division of "zhi", Zhang and the two Cheng brothers all admit that there are innate knowledge. Secondly, the "zhi" that people should pursuit are closely related to virtue. Third, although they all distinguish concrete knowledge, there are some differences in the standards of differentiation. Zhang’s the knowledge gained through enlightenment and the small knowledge of what is heard or what is seen are different in nature. In the view of the two Cheng brother, the deep and shallow knowledge shows the difference in cognitive degree, not the difference of the nature. Fourth, the tension between morality and knowledge was beginning to appear in their theories of "zhi". Zhang and Cheng Yi think that objective knowledge is helpful for extension of "zhi" while Cheng Hao think only moral knowledge is helpful. Fifthly, they have the same purpose to distinguish different kinds of "zhi". They hope to extend true knowledge otherwise the shallow and heretical views, which has the significance of determining what are the core thoughts of Confucianism and is the manifestation of becoming the sage and fully developing one's nature.

In the generation mechanism of "zhi", they all think that the innate knowledge is inherent. For concrete knowledge, Zhang and Cheng Yi both think that they are formed by the interaction of ears and eyes, objects and mind. Cheng Yi especially emphasizes "zhi" is action from within when he went to Zhang’s hometown to give speeches after Zhang passed away, which is the development of Zhang’s thoughts. Due to the emphasis on the innate knowledge and the ignorance of objective knowledge, Cheng Hao lacks the discussion about how concrete knowledge are generated. In the reasons why "zhi" can't be extended, they all attribute the reason on the mind, and such understandings benefit from each other's inspirations and influences.

In terms of extending "zhi", Zhang proposed the measures like investigating principle, changing temperament and enlarging one's mind to solve problems like the small knowledge of what is heard or what is seen, the limitations of the eyes and ears, human heat respectively, while Cheng Yi advocated that self-cultivation requires seriousness and the pursuit of learning depends on the extension of knowledge. Compared with Zhang and Cheng Yi, Cheng Hao always insists on completely preserving mind, specifically, being sincere, understanding the nature of ren, preserving ren with sincerity and seriousness and so on. This difference is rooted in their different understanding of the relationship between mind and "xing". This difference is first manifested in the solution of suffering from the influence of external things. Furthermore, the difference is also manifested in whether sincere should be combined with investigating principle. Cheng Hao thinks that there is nothing that should be done if always being sincere, while Zhang and Cheng Yi affirm the significance of investigating principle. Therefore, Cheng Hao has a lot of criticism on Zhang’s theories about extending "zhi". In addition, there are other differences, like their attitudes towards investigating principle, understanding ren, and the views about exegesis.

Zhang and the two Cheng brothers have deep communications on the theories of "zhi". Under the mutual influences and inspirations, they have developed and formed systems of "zhi" which is basically the same and with the same goal. However, due to the different understandings about the relationship between mind and "xing", there are also many differences in their theories. Generally speaking, Zhang and Cheng Hao had more direct communications and mutual inspirations. Cheng Yi absorbed more from Zhang and his brother. However, in terms of the theoretical frameworks, Zhang and Cheng Yi are more similar. The theory of "zhi" of Zhang and Cheng Yi is more systematic and delicate. As for the historical status, from the perspective of "zhi", they all put forward many creative ideas, therefore, they are all great thinkers, rather than the two Cheng brother is Zhang’s teacher or Cheng Hao is inferior to Cheng Yi.

The theories om "zhi" of Guan school and Luo school not only has a pioneering concern and discussion for "zhi", has an important influence on later generations' theories of "zhi", but also has inspirations for the understanding of knowledge, education, science and cognition at present. On the one hand, the theory of "zhi" provides important inspirations for dealing with the relationship between knowledge and morality; on the other hand, it also provides important ideas for dealing with human and nature, settling the relationships between humans and other beings.

Key Words: Zhang Zai   Cheng Hao   Cheng Yi   "zhi"   extending "zhi"

导师：魏常海教授