"We have no right to assume that any physical laws exist, or if they have existed up to now, that they will continue to exist in a similar manner in the future."

"The man who has not passed through the bitter experience of doubt, has not made a single step forward in science."

"The whole development of science is nothing but a continuous struggle to escape from the magic of the senses."

"It is not the truth that matters, but the search for it."

"The highest value of human life lies in its service to humanity."