Words Cannot Fully Express Thought.
Words cannot fully express the fundamental understanding of the world. According to The Book of Changes, words are inadequate for expressing what one means and that was why the hexagram images were made to convey the ideas of the sages. Xun Can, Wang Bi, and other metaphysicians of the Wei and Jin dynasties further elucidated this concept. Their understanding of the relationship between language and thinking was determined by their understanding of the ontological existence or original source of the world. They believed that the world’s ontological existence or original source was wu (无), which was beyond anything tangible. Wu had no specific form or attribute, and it was therefore impossible to name or describe it. Thus, language was found to have its limitations in expressing thought.
Written characters cannot fully express what the author wants to say, nor can words fully express his thought and knowledge. (The Book of Changes)
The notions beyond the images and the words beyond the “appended phrases” are deeply stored in them, and so they cannot be expressed. (Pei Songzhi: Annotations on The History of the Three Kingdoms)