"But to me all sciences seem vain..." - Quote by Leonardo Da Vinci

“Obstacles cannot bend me. Every obstacle yields to effort.”

“A luminous body will appear more brilliant in proportion as it is surrounded by deeper shadow.”

“Practice should always be based upon a sound knowledge of theory.”

“The finest and healthiest thing about science is, as in the mountains, the brisk air blowing around in it.--The spiritually delicate (such as artists) shun and slander science owing to this air.”

“Every new discovery is assumed at once into the sum total of knowledge, and with that ceases in a sense to be a discovery; it dissolves into the whole and disappears, and one must have a trained scientific eye even to recognize it after that.”

“Nobody knows how the stand of our knowledge about the atom would be without him. Personally, [Niels] Bohr is one of the amiable colleagues I have met. He utters his opinions like one perpetually groping and never like one who believes himself to be in possession of the truth.”

“Historical experience is written in blood and iron.”

“The purpose of life is to live it, to taste experience to the utmost, to reach out eagerly and without fear for newer and richer experience.”

“You achieve strength, braveness and confidence by each experience in which you really halt to search dread during the deal with”