Every judgment in science stands on the edge of error, and is personal.

It doesn't matter whether you're talking about bombs or the intelligence quotients of one race as against another if a man is a scientist, like me, he'll always say Publish and be damned.

We have to understand that the world can only be grasped by action, not by contemplation. The hand is more important than the eye ... The hand is the cutting edge of the mind.

Dissent is the mark of freedom.

The progress of science is the discovery at each step of a new order which gives unity to what had seemed unlike.

A genius is a man who has two great ideas.

When Da Vinci wanted an effect, he willed, he planned the means to make it happen: that was the purpose of his machines. But the machines of Newton ... are means not for doing but for observing. He saw an effect, and he looked for its cause.