Discernment must ultimately understand the nature of self completely. Awareness saw in the Third Foundation how the self was born from a feeling and elaborated on with thought forming the story and image of "I." Even though that process is now understood (wisdom), still, because of its tremendous momentum, there may be a residual belief in the self when it arises. Discernment wears down that residual belief by tracking the sense of self through all its manifestations until there is no longer the belief in self even though there is the occasional arising of self.