We gain our ends only with the laws of nature; we control her only by understanding her laws.

One original thought is worth the sum total of human knowledge, because it advances the sum total of human knowledge by that one original thought.

The idea that the universe is running down comes from a simple observation about machines. Every machine consumes more energy than it renders.

Dissent is the mark of freedom, as originality is the mark of independence of mind. … No one can be a scientist … if he does not have independence of observation and of thought.

Man is unique not because he does science, and his is unique not because he does art, but because science and art equally are expressions of his marvelous plasticity of mind.

The great poem and the deep theorem are new to every reader, and yet are his own experiences, because he himself recreates them.

Science is a very human form of knowledge. We are always at the brink of the known; we always feel forward for what is to be hoped. Every judgment in science stands on the edge of error and is personal. Science is a tribute to what we can know although we are fallible.