What Is the "Unity" in the "Unity of Knowledge and Action"?

This essay argues for a new interpretation of the notion of "unity" in Yangming's famous doctrine of the "unity of knowledge and action" (zhi xing he yi). I distinguish two parts of Wang's doctrine: one concerning training (gong fu), and one concerning the "original natural condition" of knowledge and action (ben ti). I focus on the latter aspect of the doctrine, and argue that Wang holds, roughly, that a person exhibits knowledge in its original natural condition if and only if the person exhibits action in its original natural condition. Moreover, I argue that Wang denies that knowledge in its original natural condition is identical to action in its original natural condition.