“The sages did not treat those who were already ill but treated those who were not yet ill. They did not try to put in order what was already in disorder but tried to prevent disorder from arising in the first place. Treating disease after it has arisen is like starting to dig a well when one is already thirsty, or only starting to cast weapons once the battle has begun. Would these also not be too late?”

—The Yellow Emperor’s Inner Classic of Medicine from 2nd century BCE