One Will, Ten Thousand Minds

Before a war starts, Sun Tzu says, weigh five factors. He lists them in the first chapter of The Art of War, which Lionel Giles translated in 1910 under the title “Laying Plans.” The first factor is the Dao, which Giles translates as “the Moral Law.”

It is easy to skip past it to the later factors, like terrain and the general. I teach engineering classes, and I find it hard to skip, because it is about a problem I know well: how to make many separate parts act together.

Here is the line in Chinese: 道者，令民与上同意也. Giles translates it this way: “The Moral Law causes the people to be in complete accord with their ruler, so that they will follow him regardless of their lives, undismayed by any danger.”

The key words are 同意. Today they mean “to agree.” But taken one character at a time, 同 means “same” and 意 means “intent” or “will.” So Sun Tzu’s first condition is simple. The people and the ruler must want the same thing, and not only on the surface. Giles’s “complete accord,” and a people ready to face death without fear, describe real conviction: the people believe in the cause they are fighting for.

The Dao’s place on the list matters too. Sun Tzu puts it first, before Heaven, Earth, the Commander, and Method and Discipline. That order suggests a war is first a contest of politics and morale, and only then a contest of weapons and tactics. On this reading, a state’s real strength starts with the hearts of its people.

This shared intent sounds like a modern idea. In 2005, the psychologist Michael Tomasello and his colleagues published a paper in Behavioral and Brain Sciences about “shared intentionality.” It means working with others toward a goal that everyone holds together. From their research, they argued that great apes understand that others have goals, but do not make goals together. Human children start doing it around their first birthday. Tomasello argues that much of human culture, including language, grows from this ability.

Coordination is a familiar problem in the communications engineering courses I teach, so I can see why the comparison is attractive. In a network, coordination is expensive. Every decision that needs agreement costs messages and time, and messages can get lost. If every part already wants the same result, much of that cost disappears. Each part can guess what the others will do without asking. An army with one shared intent can act like one system, with no need for a messenger at every step.

But one word in the line changes the picture. It does not change whether the people believe. It changes where their belief comes from. The line does not say the people and the ruler come to share an intent. It says the Dao 令 the people to share it. The character 令 means “to cause,” and also “to order.” The shared intent starts with the ruler.

The classical commentators agree on this, even when they disagree on the method. Cao Cao, the late Han general and ruler (155 to 220) whose commentary is the oldest that survives, explained this Dao as 道之以教令, “guiding them with instructions and orders.” He also read the line’s last word, 危, as “doubt.” On his reading, the people follow “without doubt,” not only “undismayed by any danger” as Giles has it.

Later commentators gave a warmer reading. Du Mu said the Dao is 仁义, benevolence and righteousness, and quoted Xunzi: when a government is well run, the people feel close to their superiors, take joy in their ruler, and think little of dying for him. Zhang Yu wrote that soldiers moved by gratitude share life and death with their superiors, with no doubt or fear. The warmer readings stress that the people’s conviction is real. But in all of them, the ruler is the one who produces it.

Tomasello’s idea is built among equals. Each person holds the goal, each person knows the others hold it too, and they arrive at it together. Sun Tzu describes something else. The ruler’s intent comes first, and the people come to share it because of how he governs. The test is whether they will follow him “regardless of their lives.”

The two ideas also do different jobs. Tomasello describes something ordinary that all people can do, like two small children carrying a box together. Sun Tzu describes something a state must create in its people, and he treats it as something to measure. The first of his seven comparisons before a war asks: which of the two rulers has the Moral Law? For Sun Tzu, it is something one side can have and the other can lack, not a fact about human nature.

So I do not think Sun Tzu predicted shared intentionality. He saw the same benefit, many minds acting as one, but he believed it came from a different place. Tomasello’s version is built from below, among equals. Sun Tzu’s version is earned from above, by a ruler the people trust. That makes it fragile in a way an engineer would recognize: it has a single point of failure. It rests on one ruler’s conduct, so if he loses the people’s trust, the whole army can lose its shared will at once.