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

Beyond all our actions stands the larger shadow: How are we to choose between what we have been taught to think right and something else which manifestly succeeds?

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.

Nations in their great ages have not been great in art or science, but in art and science.

All science is the search for unity in hidden likenesses.

Astronomy is not the apex of science or of invention. But it is a test of the cast of temperament and mind that underlies a culture.

I grew up to be indifferent to the distinction between literature and science, which in my teens were simply two languages for experience that I learned together.