“Is it not true that no two human beings understand anything whatsoever about each other, that those who consider themselves bosom friends may be utterly mistaken about their fellow and, failing to realize this sad truth throughout a lifetime, weep when they read in the newspapers about his death?”

Source: The Rise of Endymion (1997), Chapter 33 (p. 684)

Source: Your Best Life Now: 7 Steps to Living at Your Full Potential

Something Like an Autobiography (1981)
Context: Although human beings are incapable of talking about themselves with total honesty, it is much harder to avoid the truth while pretending to be other people. They often reveal much about themselves in a very straightforward way. I am certain that I did. There is nothing that says more about its creator than the work itself.

In the song Lagrimas de Sofrimento http://www.vagalume.com.br/mc-daleste/lagrima-de-sofrimento.html

As quoted in The Sunday Telegraph, London (1975), and Rebecca West : A Life (1987) by Victoria Glendinning, p. xi

Criterion Collection essay on Rashamon, excerpted from Something Like an Autobiography as translated by Audie E. Bock (1982) http://www.criterion.com/current/posts/196-akira-kurosawa-on-rashomon
Context: Human beings are unable to be honest with themselves about themselves. They cannot talk about themselves without embellishing. This script portrays such human beings — the kind who cannot survive without lies to make them feel they are better people than they really are. It even shows this sinful need for flattering falsehood going beyond the grave — even the character who dies cannot give up his lies when he speaks to the living through a medium. Egoism is a sin the human being carries with him from birth; it is the most difficult to redeem. This film is like a strange picture scroll that is unrolled and displayed by the ego. You say that you can’t understand this script at all, but that is because the human heart itself is impossible to understand. If you focus on the impossibility of truly understanding human psychology and read the script one more time, I think you will grasp the point of it.

Scientists
The Note-Books of Samuel Butler (1912), Part XIV - Higgledy-Piggledy