It is said that Knowledge is contained in the gap. Knowledge in a book is not contained in the letters. The knowledge is held on the page, the backdrop of the letters. Knowledge of the world is contained in the backdrop, only perceptible to those who can see it. The secret doctrines remain secret to those who read them, less they can see the backdrop.
As Bruce Lee said,
“A wise man can learn more from a foolish question than a fool can learn from a wise answer.”