Shu

The exchange is Analects 15:23. Zigong, the disciple with the merchant's mind, asks a merchant's question: is there one word which may serve as a rule of practice for all one's life? It is a request for compression, ethics at its minimum viable size, and Confucius, who elsewhere refuses such shortcuts, this time supplies one: is not shu such a word? What you do not want done to yourself, do not do to others. The choice of shu over grander candidates is itself the teaching. Asked for one word, Confucius does not name humaneness, the crown of his ethics, or rightness, or ritual; he names the operation by which an ordinary person, in an ordinary moment, can compute what humaneness requires: consult your own feelings and refuse to export what you would not import.

The formula needs no learning, no leisure and no priest, which is exactly what fits it for all one's life, a rule usable at every age, in every station, at the speed of daily decisions. Confucius was frank about the difficulty concealed in the simplicity: when Zigong on another occasion announced that he did not do to others what he did not want done to himself, the Master replied that he had not yet reached that point. The rule can be stated in a breath and practiced for sixty years without exhausting it, and the tradition treats that ratio, minimum statement to maximum demand, as the mark of its truth.

The character shu is built from two elements: ru, meaning like or as, above xin, the heart. The graph is thus readable as a small diagram of the virtue: as the heart, one heart taken as like another. The commentarial tradition made the etymology doctrinal, glossing shu as tui ji ji ren, extending oneself to reach others: one takes one's own case, one's own recoil from insult, hunger for recognition, dread of injury, and treats it as valid evidence about every other case. The method deserves notice for what it does not require. It does not require agreement on doctrine, shared ancestry or shared rank; it requires only that the other be conceded a heart like one's own, whereupon one's self-knowledge becomes, instantly, knowledge of how they may and may not be treated. This is why shu is often called the method of ren, humaneness.

Ren names the disposition of fellow-feeling; shu is its working procedure, the likening by which fellow-feeling computes its duties. The negative form, do not impose what you would not suffer, keeps the procedure honest: it forbids using oneself as the measure of what others must enjoy, only of what they must be spared, a modesty later comparative ethicists came to prize when weighing the world's reciprocity formulas against one another. In the Confucian frame the likening is also self-cultivating; each act of extension enlarges the heart doing the extending, so that the procedure and the virtue grow together over a lifetime.