There are different name for it from different cultures or philosophies.
In Daoism it is called the absolute or the undifferentiated one or Wuji.
In Zen it is called satori or kensho.
In Yoga or Buddhism its called samadhi.
In Sufism it is called fana and the Quaker call it inner light.
So many names to describe the same phenomenon.
But all these names describe the same state of mind.
I prefer the undifferentiated one. It is for me the description who shows clear in the state of highest consciousness there is no movement, differentiation, no two or three. If you are able to be in that state of mind you are with God, Buddha, Allah or the One. Or better said you are in that moment the named ones. With the experience of the highest consciousness your mind will change. From now on you know we are not separated and we all have the same roots even it get called differently in different cultures.
The use of paradox in Zen teaching is quite a normal way to do. It is to cut or destroy the normal intellect thinking. The question who a man really is can´t explained by words. The answer can be found only with the experience of intuitive knowledge. With help of paradoxes disciple can get leaded to the right path. A Zen master leads his followers and students into the truth. Sometime it is done by a single phrase who intuitive designed to destroy the student particular of so called demon of ignorance.
For those who discovered the nature of Reality, there is nothing old or new, concepts become meaningless and reason leads to error.
In Zen or Chan in Chinese therm there is the concept of sudden and complete enlightenment. It is possible here and now if you are able to release. To get it t is necessary to rise above such relative concepts as good and evil, sought and found,enlightened and unenlightened and all the rest of these kind of paradigm. In daoist therms it is be explained like before Yin Yang shows up or be one or also Wuji. Intuitive realization of the unity or of the Absolute means there is nothing to be attained, one does not enter Nirvana. Intuitive realization of oneness is like to enter the Nirvana there no other place to go or to enter. The one who have actually achieved these level are knowing about the impossibility of communicating it in words.
So da fangen wir mal an aus der Sammlung und der Erinnerung einiges zusammen zu tragen. Brainstorming> mal sehen was raus kommt Zustand des Hirngeschwafels:
Leben und Tod beides ist gut. Ist vom gleichen Ursprung. Wasser wird Eis und schmilzt wieder zu Wasser. Was geboren ist stirbt weder, was gestorben ist erwacht wieder zum Leben. Letztendlich ist es eins. Beruhigend und auch gut so.