The rational is reliable precisely because it has its source in sense perceptions,other- wise it would be like water without a source,a tree without roots,subjective,self-engendered and unreliable.

• 理性的东西所以靠得住，正是由于它来源于感性，否则理性的东西就成了无源之水，无本之木，而只是主观自生的靠不住的东西了。