Study is to study what cannot be studied. Undertaking means undertaking what cannot be undertaken. Philosophizing is to philosophize about what cannot be philosophized about. Knowing that knowing is unknowable is true perfection.
ZhuangziA battering ram can knock down a city wall, but it cannot stop a hole. Different things have different uses.
ZhuangziThe saying goes, 'The sage rests, truly rests and is at ease.' This manifests itself in calmness and detachment, so that worries and distress cannot affect him, nothing unpleasant can disturb him, his Virtue is complete and his spirit is not stirred up.
ZhuangziAs regards the quietude of the sage, he is not quiet because quietness is said to be good. He is quiet because the multitude of things cannot disturb his quietude. When water is still, one's beard and eyelashes are reflected in it. A skilled carpenter uses it in a level to obtain a measurement. If still water is so clear, how much more are the mental faculties! The mind of the sage is the mirror of heaven and earth in which all things are reflected.
Zhuangzi