本文取徑周代禮學，特別是其中的威儀觀，以揭示荀子的文化保存意識與思想內在的組成要素。其中依序提出幾項看法：首先，威儀之執持，非但具有一定程度的困難，且極易放失，實透露人性的不圓滿。而荀子性惡論之形成，當與此密切相關。復次，威儀的訂定，係依人類官能與心智的適當狀態為標準，周人對感官接觸外界時，能否呈現「和」的感受甚為講究，蓋其以為外物可直接影響個體之心智、言行。而荀子的「治氣養心」說，當即該說的再現。第三，從春秋戰國時期諸多踐禮的案例可知：心理、情感的失和，於時人乃至孔門高足均層出不窮，則荀子之性惡論，倘能置諸此「失和危機」予以考量，自有一番意義。第四，威儀觀對人類智慧、感知侷限的認識，啟發荀子天人有分之說，然亦同時宣告荀子與周禮間，將由此萌生斷裂。

This article examines Zhou dynasty rites and etiquette, in particular the concept of weiyi 威儀, to shed light on Xunzi’s 荀子 awareness of cultural preservation and the main factors in the formation of his thought. The article proposes the following: first, upholding weiyi not only presented certain difficulties, but was also easily lost or cast aside revealing the imperfection of human nature. This view was key to the formation of Xunzi’s theory that human nature is eventually bad. Second, the concept of weiyi takes as its standard an appropriate state of the senses and the intellect; the Zhou were very particular about whether or not they were able to feel harmony in their sense experience. They saw outside objects as being able to directly influence the mind and actions of the individual, and Xunzi’s idea of “controlling the vital energy and nourishing the mind” was a restatement of this. Third, the many examples of the practice of ritual and etiquette from the Spring and Autumn and Warring States periods tell us that the minds and emotions of the people of the time, even the important Confucians, could fall out of harmony. Consequently it is meaningful to examine Xunzi’s ideas about human nature in this regard. Finally, the limitations of human wisdom and awareness inherent in the concept of weiyi inspired Xunzi’s theory of the division between Heaven and humankind. At the same time it was also a declaration of Xunzi’s split from the tradition of the Zhou Li 周禮.