By 1508 Wang Yangming had spent years doing exactly what Zhu Xi's orthodoxy told him to do, investigating the principle in things one object at a time, famously staring at bamboo stalks for days as a young man in the hope that principle would disclose itself. It never did, and the failure sat with him through a court disgrace, a beating and exile to a remote, malarial post as a minor official among the Miao and Yi peoples of Guizhou. Sleeping in a stone coffin he had built himself against assassins, he had, by his own later account, a sudden nocturnal realization: principle is not to be sought in bamboo or in any external thing at all, because the mind itself is principle.
From that single reversal a whole rival Neo-Confucianism followed. If the mind already contains principle, moral knowledge cannot be a distant goal reached through accumulated study; it must be an innate capacity, liangzhi, that every person already possesses and only needs to stop obscuring with selfish desire. And if the knowledge is already there, then the old sequence of first know, then act collapses: knowledge and action are one act (zhixing heyi), because genuinely knowing a thing is right already is doing it, and a person who claims to know but does not act on it never really knew at all. Wang spent the following two decades as a soldier, provincial governor and constant traveling teacher, putting the doctrine to use suppressing a major rebellion while never stopping his seminars, and it became, particularly through his students' later radicalization of it, the dominant challenge to Cheng-Zhu orthodoxy for the rest of the Ming dynasty and a major current in early modern Japanese thought as Yomeigaku.