http://www.taoteching.org/
"My words are easy to understand
And my actions are easy to perform
Yet no other can understand or perform them.
My words have meaning; my actions have reason;
Yet these cannot be known and I cannot be known."
"Understanding" is a pretty complicated process. Hofstadter had a pretty good definition: Understanding is a homomorphy between two symbolic systems.
You can write a few 100s pages just on this topic.
