Zhouyi is the leading one of the Five Chinese Classics. Where Yi stems from Qi, which stems from numbers, image-numerology stems from all things on earth and argumentation elaborate based on trigram images. Hence, both the image-numerology and the argumentation are indispensable in the study of Zhouyi. The image-numerology refers to various forms and properties symbolized by the symbols, numbers, and related schemas of the trigrams in Zhouyi; the argumentation refers to the philosophies of nature, society and life implied by the texts of trigrams in Zhouyi. The Annotated Catalog of the Complete Imperial Library reads, “in Han Dynasty the Confucianists discussed about image-numerology which was not very different from the ancient time. It was passed down to Jing Fang and Jiao Yan-shou, and changed to a prayer for blessing and divination; being passed down to Chen Bo and Shao Yong, once again it was changed to the exploration into the mysteries of heaven and earth, thus, Yi was no more relevant to civilian use. Wang Bi dismissed image-numerology entirely and discussed based on Lao Zi and Zhuang Zi; the image-numerology was then handed down to Hu Yuan and Cheng Yi, who were the first to elaborate on Confucian principles; subsequently, it reached Li Guang and Yang Wanli, who made reference to historic events, such that theories increasingly emerged on Yi. Debates had begun among the two sects and six schools.” In summary, the history of Yi research is a dialectic process between image-numerology and argumentation, where the study of Yi research by the approach of image-numerology and argumentation has the advantage of grasping the critical points and being concise.
The literature including from pre-Qing Yijing to the Commentary on the Book of Changes has copious arguments on both image-numerology and argumentation, with Commentary on Trigrams becoming the basic document for numerologists. Whereas scholars in Eastern and Western Han Dynasty focused on image-numerology over argumentation; Zheng Xuan, who mastered both contemporary and conventional literature, commented on Yi by the five elements and Na-Jia, yet he still interpreted the meanings and principles of Zhouyi as simple, change and constant, which demonstrated that neither of image-numerology and argumentation can be disregarded. Wang Bi of Wei Dynasty commented on Zhouyi by saying “retaining meanings and forgetting image” and pioneered the practice of metaphysical Yi. Subsequently, Han Kang-Bo of Jin Dynasty continued to comment and made annotation on the Commentary on the Appended Phrases, Explanation of the Trigrams, the Sequence of the Hexagrams, and Miscellaneous Hexagrams, etc. Besides, Kong Ying-Da of Tang Dynasty commented on Zhouyi Zhengyi, which allowed the school of argumentation to dominate by taking the advantage of the imperial examination; however, when Li Ding-Zuo collected the comments by prior scholars and added his own comments to compose the Notes to Zhouyi , he retained much literature on image-numerology. From image-numerology, which is the source for argumentation, it is possible to propose one’s own humane view and mind thinking, while argumentation relates more to self-cultivation and awareness of crisis. And, numerology, which uses image-numerology as a vehicle, relies on probabilities and the existence of psychological effects like sweet talks and self-recognition. For numerologists, sense of virtues, ever self-improving and keeping away from risks became burdens instead.
Image-numerology and argumentation are the two sides of a coin, where the latter is interpretation and applications of the former. And, “argument” is the body of Yi and “image” is the application of Yi. The former is implicit, while the latter is explicit, but they cannot be separated; thus, it is said that the body and the application are of a same source, without differences in revealing the minute things. Either may be biased but neither may be omitted, as argumentation cannot do without image-numerology, and vice versa. However, both have effects on people’s quest for “humanity” in literature, history, philosophy, religion, arts as well as society. Thanks to the progress of natural science, image-numerology was also well developed in Han Dynasty, while Confucianism also blended in ethic view through Yin and Yang and Five Elements amid the atmosphere of “interactions between Heaven and Man”. Yet, that also promoted diversification of astrology, with Meng Xi and Jing Fang’s theories of image-numerology becoming the hot bed for development of numerology. Numerology discusses fame and money that are irrelevant to humane reasons and principles and astrologists conjecture about one’s mind seeking lucks and avoiding risks, which, in the name of metaphysics, was degenerating toward “god’s texts”. As such, image-numerology and meanings and principles that were about Yin and Yang were still different from numerology that focused on the actions between Five Elements.