Chuang Tzu 6.1

He who knows the part which the Heavenly in him plays, and knows also that which the Human in him ought to play, has reached the perfection of knowledge. 

He who knows the part which the Heavenly plays knows that it is naturally born with him; he who knows the part which the Human ought to play proceeds with the knowledge which he possesses to nourish it in the direction of what he does not yet know—to complete one's natural term of years and not come to an untimely end in the middle of his course is the fullness of knowledge. 

Although it be so, there is an evil attending this condition. Such knowledge still awaits the confirmation of it as correct; it does so because it is not yet determined. 

How do we know that what we call the Heavenly in us is not the Human? And that what we call the Human is not the Heavenly? There must be the True man, and then there is the True knowledge.