“Even the most elevated psychological understanding is not a loving understanding.”

The First Law. All human behavioral traits are heritable.
The Second Law. The effect of being raised in the same family is smaller than the effect of genes.
The Third Law. A substantial portion of the variation in complex human behavioral traits is not accounted for by the effects of genes or families.
Kindle locations 8005, 8010.
The Blank Slate (2002)

Biographical memoir: "John von Neumann (1903 - 1957)" in Year book of the American Philosophical Society (1958); later in Symmetries and Reflections : Scientific Essays of Eugene P. Wigner (1967), p. 261
Context: A deep sense of humor and an unusual ability for telling stories and jokes endeared Johnny even to casual acquaintances. He could be blunt when necessary, but was never pompous. A mind of von Neumann's inexorable logic had to understand and accept much that most of us do not want to accept and do not even wish to understand. This fact colored many of von Neumann's moral judgments. "It is just as foolish to complain that people are selfish and treacherous as it is to complain that the magnetic field does not increase unless the electric field has a curl. Both are laws of nature." Only scientific intellectual dishonesty and misappropriation of scientific results could rouse his indignation and ire — but these did — and did almost equally whether he himself, or someone else, was wronged.

Nous avons psychologisé comme les fous, qui augmentent leur folie en s’efforçant de la comprendre.
"La Fanfarlo" (1847) http://fr.wikisource.org/wiki/La_Fanfarlo

Letter to Dr. Theodore Canisius (17 May 1859)
1850s

Source: The Scientific Analysis of Personality, 1965, p. 18

The Decline and Fall of Science (1976)

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.

Variant: People understand me so little that they do not even understand when I complain of being misunderstood.
Source: The Journals of Kierkegaard