"The greatest obstacle to discovering the shape of the earth, the continents, and the oceans was not ignorance but the illusion of knowledge."
(Daniel Boorstin)

"The man of knowledge must be able not only to love his enemies but also to hate his friends."
(Friedrich Wilhelm Nietzsche)

"There is a plague on Man, the opinion that he knows something."
(Michel de Montaigne)

"There is much pleasure to be gained from useless knowledge."
(Bertrand Arthur William Russell, 1872-1970)

"To know someone with whom you can feel there is understanding in spite of distances or thoughts unexpressed ... that can make this life a garden."
(Johann Wolfgang von Goethe, 1749-1832)

"We learn nothing from the things we know."
(John Cage, M, Writings 1967 - 1972)