The Essence of the 'Great Treatise A': A Philosophical Inquiry into the Gentleman's Establishment of Life and the Order of the *Yi*
This article deeply interprets the core proposition from the 'Great Treatise A'—'That which the gentleman dwells in and finds peace is the order of the *Yi*.' It examines how the gentleman, by internalizing the Way of Heaven and Earth and utilizing the *Book of Changes* as the foundation for establishing his life, achieves a state of 'auspiciousness without detriment' through observing the images and contemplating the textual explanations, situated within the Pre-Qin context and the Confucian tradition.
IV. From Eight Trigrams to Sixty-Four Hexagrams—The Need for Increased Complexity
Fuxi created the Eight Trigrams, but with only eight arrangements, they were insufficient to describe complex human affairs and natural phenomena. Thus, later (traditionally attributed to King Wen), the Eight Trigrams were overlapped in pairs to form sixty-four hexagrams (8² = 64) and three hundred and eighty-four lines.
Why develop from Eight to Sixty-four hexagrams$6
The Xì Cí Xia Zhuàn states:
"The Eight Trigrams being arrayed, the Images are contained within them. Thereupon they are doubled, and the Lines are contained within them. Firmness and yielding push each other, and change is contained within them. Appending words to it names it; action is contained within it."
"Ba Gua cheng lie, xiang zai qi zhong yi. Yin er chong zhi, yao zai qi zhong yi. Gang rou xiang tui er sheng bian hua. Xi ci yan er ming zhi, dong zai qi zhong yi (八卦成列，象在其中矣。因而重之，爻在其中矣。刚柔相推而生变化。繫辞焉以命之，动在其中矣)."
"The Eight Trigrams being arrayed"—the eight trigrams are set up. "Thereupon they are doubled"—they are then superimposed. "The Lines are contained within them"—the Lines (six lines) are contained within them.
Trigrams of three lines could only describe relatively simple situations. Hexagrams of six lines could describe more complex situations. Six lines are divided into upper and lower bodies (three lines each). The upper body represents the external environment, and the lower body represents the internal state (or other corresponding relations). Their interaction allows for a more precise description of various complex human and environmental situations.
This development from simplicity to complexity reflects the continuous improvement of cognitive capacity and the growing needs for cognitive precision among the ancients.