"Imagination is more important than knowledge."

"The greatest obstacle to progress in science is the belief that one knows something which one does not know."

"The world is a book, and those who do not travel read only one page."

"The world is not to be understood by reason alone. It is also to be understood by intuition and feeling."

"My solution was not motivated by the desire to reduce the number of independent constants in nature, but rather by the desire to avoid the infinite self-energy of the electron."