The father of a good friend of ours made her memorize this ...
1. He who knows not, but thinks he knows, he is a fool - shun him.
2. He who knows not and knows he knows not, he is a child - guide him.
3. He who knows and knows not he knows, he is asleep - awaken him.
4. He who knows and knows he knows, he is wise - follow him.
She recalled this after listening to musings of Ed Burns on the writing of his book, Secrets of the Rockstar Programmers. She noted the similarity to the five orders of ignorance, described in the book.