"The important thing is not to stop questioning. Curiosity has its own reason for existing."
"Imagination is more important than knowledge. For knowledge is limited, whereas imagination embraces the entire world."
"Science is a wonderful thing if one does not have to earn one's living at it."
"Everything should be made as simple as possible, but not simpler."
"The true sign of intelligence is not knowledge but imagination."
"Reality is merely an illusion, albeit a very persistent one."
"Look deep into nature, and then you will understand everything better."