One of the first results of the attention to phenomena is to observe the amazing number of varieties in the world, hence the idea of difference or diversity. (In fact, we can already see difference or diversity in the concepts of "yin and yang" and the Five Elements.) With this there appeared a word related to this idea, i.e. "harmony" (he). The earliest Chinese concept of "harmony" was related to musical aesthetics and can be traced back to Canon ofYao in the Book of Documents:
Poetry is the expression of earnest thought; singing is the prolonged utterance of that expression; the notes accompany that utterance, and they are harmonized themselves by the standard-tubes. (In this way) the eight different kinds of musical instruments can be adjusted so that one shall not take from or interfere with another; and spirits and men are brought into harmony.
Here we see phrases like "they are harmonized themselves by the standard-tubes" and "the eight different kinds of musical instruments can be adjusted," and the two important concepts of "harmony" (he) and "accord" (xie), which were used to describe the kind of harmony expected to exist between musical tones and musical instruments.
The Spring and Autumn Period saw a deepening of the understanding of diversity, which was most typically represented by the discourses of Shi Bo and Yan Ying. The words of the former are recorded in The Discourse of Zheng in The Discourses of the States:
Harmony leads to growth and development, while sameness would put an end to it. To combine one thing with another on an equal footing is called harmony. As such it can stimulate the growth of things. If you try to make up for the deficiency of something with the same thing, it would come to end and be abandoned. So ancient rulers combined earth with metal, wood, water and fire to create all things in the world ... Such is the apex of harmony. So ancient kings married women from different clans, sought wealth from across the land, and selected officials and advisors to deal with all kinds of affairs, in order to achieve a harmonious governance. A single sound cannot be pleasant to hear, a single color cannot make a beautiful design, a single taste cannot make fine food, and a single thing in isolation from others cannot be evaluated. If the ruler eschews harmony and seeks only sameness, heaven would deprive him of the capacity of sound judgment. If so, how could he avoid pitfalls?
Yan Ying's words are found in The 20th Year of the Reign of Duke Zhao in Zuo Zhuan:
Harmony can be compared to thick soup, in which fish and meat are cooked together with water, sauce, salt and plums, heated with firewood underneath. The chef would mix them well, compensating for what is lacking and reducing what is excessive. Such soup, when served to the gentleman, could bring serenity to his mind. The same is true of the relationship between the ruler and his ministers. What the ruler approves of may have something objectionable in it, and his ministers may offer to rectify that so as to make the whole thing approvable; what the ruler disapproves of may have something approvable in it, and his ministers may point this out so that he might change his mind. ... But things are different nowadays. What the ruler approves of, his ministers also approve of; what the ruler disapproves of, his ministers also disapprove of. This is like cooking water in water - what could eat it? - or like playing the same tune on the lute and the zither - what could enjoy that kind of music?
Both Shi Bo and Yan Ying were expressing the idea of embracing diversity and opposing uniformity. Specifically speaking, they expressed two meanings:
1) They gave the reason for opposing uniformity ("sameness would put an end to [development and growth]" and "If you try to make up for the deficiency of something with the same thing, it would come to end and be abandoned") Here "uniformity" also has two meanings: invariability ("A single sound cannot be pleasant to hear, a single color cannot make a beautiful design, a single taste cannot make fine food, and a single thing in isolation from others cannot be evaluated") and sameness ("This is like cooking water in water - what could eat it? - or like playing the same tune on the lute and the zither - what could enjoy that kind of music?").
2) They explained that they embraced diversity because it can "stimulate the growth of things." That is to say, different things can generate, support or complement each other. Only in this way can it be possible to compensate for weaknesses and "bring all kinds of things into existence."
Such discourses contain the profound observation that no category of things can be perfect and represent everything. It is noteworthy that both Shi Bo and Yan Ying used the concept of "harmony" in their discussion of difference, which has a very clear meaning - unity of diversity10.
Such an understanding of the objective world would translate into a method of subjective thinking characterized by attention to difference. Here Sun Tzu's thought is a case in point. For instance, he noted that one must take into full consideration different topographic and geographic conditions before choosing the proper method of operation:
The natural formation of the country is the soldier's best ally; but a power of estimating the adversary, of controlling the forces of victory, and of shrewdly calculating difficulties, dangers and distances, constitutes the test of a great general. (Terrain, The Art of War)
Sun Tzu's understanding of geographic and topographic differences is mainly reflected in two chapters of The Art of War - Terrain and The Nine Situations. In the former, terrain is divided into six categories:
We may distinguish six kinds of terrain, to wit:
(1) Accessible ground; (2) entangling ground; (3) temporizing ground; (4) narrow passes; (5) precipitous heights; (6) positions at a great distance from the enemy.
The latter proposes nine situations:
The art of war recognizes nine varieties of ground: (I) dispersive ground; (2) facile ground; (3) contentious ground; (4) open ground; (5) ground of intersecting highways; (6) serious ground; (7) difficult ground; (8) hemmed-in ground; (9) desperate ground.
Sun Tzu emphasizes that the methods of operation designed with regard to different terrains are totally different. For instance,
Therefore, on dispersive ground, I would inspire my men with unity of purpose. On facile ground, I would see that there is close connection between all parts of my army.
On contentious ground, I would hurry up my rear.
On open ground, I would keep a vigilant eye on my defenses. On ground of intersecting highways, I would consolidate my alliances.
On serious ground, I would try to ensure a continuous stream of supplies. On difficult ground, I would keep pushing on along the road.
On hemmed-in ground, I would block any way of retreat. On desperate ground, I would proclaim to my soldiers the hopelessness of saving their lives. (The Nine Situations)
As we can see, Sun Tzu has first all made a fine distinction between geographic and topographic conditions, and then proposed principles of operation suited to different conditions. This makes operation highly well-targeted or scientific, thereby guaranteeing the possibility of victory".