The most remarkable discovery ever made by scientists is science itself. The discovery must be compared in importance with the invention of cave-painting and of writing.

A man becomes creative, whether he is an artist or scientist, when he finds a new unity in the variety of nature. He does so by finding a likeness between things which were not thought alike before.

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

The values by which we are to survive are not rules for just and unjust conduct, but are those deeper illuminations in whose light justice and injustice, good and evil, means and ends are seen in fearful sharpness of outline.

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.

All those formal systems, in mathematics and physics and the philosophy of science, which claim to give foundations for certain truth are surely mistaken. I am tempted to say that we do not look for truth, but for knowledge. But I dislike this form of words, for two reasons. First of all, we do look for truth, however we define it, it is what we find that is knowledge. And second, what we fail to find is not truth, but certainty; the nature of truth is exactly the knowledge that we do find.

The largest single step in the ascent of man is the change from nomad to village agriculture.