Truth is seen, not heard.

In the first year of the Shenjue era of Emperor Xuan of the Han, 61 BCE, the Qiang people (羌族) of the western frontier rose in revolt. The emperor wished to assemble an army to suppress them but hesitated over whom to send. At a court council, several young generals argued, "Let us sweep them away at a stroke with a hundred thousand troops." The cautious emperor sent a man to the white-haired veteran Zhao Chongguo (137–52 BCE). He was 76 and had retired to his home. The emperor's envoy asked, "How should we subdue the Western Qiang?" Zhao answered — "百聞不如一見. 兵難隃度. 臣願馳至金城, 圖上方略." A hundred hearings are not worth one seeing. Matters of war are hard to gauge from afar. I beg to ride to Jincheng (金城, near present-day Lanzhou), see the terrain with my own eyes, and submit a strategy drawn from it. This passage is the source of "百聞不如一見" as recorded in the Book of Han. Zhao did indeed ride to the frontier and survey the ground for several months. He submitted a memorial whose conclusion ran exactly opposite to the court's expectation — "Do not send a hundred thousand troops. The land of the Qiang is good for farming. Instead of an army, set up agricultural garrisons (屯田), settle farmers there, and in time they will naturally become our own." The young generals scoffed, but the emperor trusted Zhao. The result was astonishing. Within a year the Western Qiang region was stabilized, and the Han lost scarcely a single soldier. It became one of the Han's greatest successes in frontier management.

The root of the English "evidence" is the Latin "evidentia." The word divides in two: ex- (out, fully) + videre (to see). Translated literally, "a showing forth, a being plainly manifest." The Roman rhetorician Cicero all but invented the word. Translating the Greek "enargeia" (vividness, clarity), Cicero coined "evidentia." His definition was lucid — "that which feels as though it were set before the eyes (quasi rem oculis subiectam)." Evidentia, then, was not "that which exists" but "that which is shown to the eye." In Latin, videre was not simply "to see." It also carried the sense "to know, to understand" — the same logic by which the English "I see" comes to mean "I understand." The Proto-Indo-European root *weid- ("to see, to know") gives, besides Latin videre, the Greek idein ("to see"), the Sanskrit veda ("knowledge"), and the ancestor of English wit/wise. "Seeing" and "knowing" were one and the same root. "Evidence" was first used in English in the mid-14th century, mostly in the sense of "plainness, manifestation," in the literature of Geoffrey Chaucer's era. From the 17th century onward, hardening into the technical term "legal evidence" in the English courts, it settled into its modern meaning. What is interesting is that, through Francis Bacon and the scientific revolution of the 17th century, the concept of "scientific evidence" was born. Bacon declared, "What is not observed is not science." This is, word for word, the same as Zhao Chongguo's "百聞不如一見."