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.
V. Military Strategy and the Yi
The thought in The Art of War (Sunzi Bingfa) has deep origins in the Zhou Yi.
Sunzi Bingfa, Empty and Full (虚实篇):
"The shape of troops is like water; the shape of water is to avoid the high ground and seek the low; the shape of troops is to avoid the strong and strike the weak. Water shapes its flow according to the ground; troops shape their victory according to the enemy. Therefore, troops have no constant form, just as water has no constant shape. He who can change according to the enemy and achieve victory is called 'Divine.'"
"Bing wu chang shi, shui wu chang xing (兵无常势，水无常形)." "Troops have no constant form, just as water has no constant shape." "He who can change according to the enemy and achieve victory is called 'Divine'."
This completely aligns with the spirit of "only change is appropriate" in the Xì Cí Zhuàn.
Furthermore, Sunzi Bingfa, Laying Plans (始计篇):
"War is a matter of vital importance to the state; the way of life and death; the road to survival or ruin. It cannot be left unexamined. Therefore, examine it by the five factors and compare them by calculation to ascertain the reality: First, the Moral Law (Dao); Second, Heaven; Third, Earth; Fourth, the Commander; Fifth, Method (Fa)."
"Jing zhi yi wu shi (经之以五事)." "Examine it by the five factors." "First, the Moral Law (Dao)." "The Moral Law causes the people to be in accord with their ruler, so that they will follow him in life and death, and will not fear danger."
The "Moral Law" here—"causes the people to be in accord with their ruler"—is precisely achieved by "treading on trustworthiness and contemplating compliance." Only when practicing trustworthiness and aligning with the people's feelings will the people share life and death with the ruler and not fear danger.