In the section of "uncertainty of one's essence", I mentioned it was very difficult to understand one's essence no matter how hard one would try because of signals from the outside world and emotions welling up from inside. One's essence is no more than a critical mind. In other words, a person with a critical mind on "what is one's essence?" is trying to see the whole of him/herself. There is a similar idea in Mahayana Buddhism, in which they explain that difficulties occur when one tries to know the whole, of which s/he is a part. In short, difficulties occur because three undifferentiated elements of the subject, the object and the actions of recognition create restrictions.