In the moment of appreciation we live again the moment when the creator saw and held the hidden likeness.

We are all shot through with enough motives to make a massacre, any day of the week that we want to give them their head.

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.

That series of inventions by which man from age to age has remade his environment is a different kind of evolution -- not biological, but cultural evolution . . . "The Ascent of Man.

Every animal leaves traces of what it was; man alone leaves traces of what he created.

The hand is the cutting edge of the mind.

Da Vinci was as great a mechanic and inventor as were Newton and his friends. Yet a glance at his notebooks shows us that what fascinated him about nature was its variety, its infinite adaptability, the fitness and the individuality of all its parts. By contrast what made astronomy a pleasure to Newton was its unity, its singleness, its model of a nature in which the diversified parts were mere disguises for the same blank atoms.