There is a great satisfaction in building good tools for other people to use.

Sometimes we talked about the nature of the human soul and about the Cosmic Unity of souls that I had believed in so firmly when I was 15 years old. My mother did not like the phrase Cosmic Unity. It was too pretentious. She preferred to call it a world soul.

Most of the papers which are submitted to the Physical Review are rejected, not because it is impossible to understand them, but because it is possible. Those which are impossible to understand are usually published.

There is no way to find the best design except to try out as many designs as possible and discard the failures.

For some days I quietly worked out in my own mind the metaphysics of Cosmic Unity. The more I thought about it, the more convinced I became that it was the living truth. It was logically incontrovertible. It provided for the first time a firm foundation for ethics. It offered mankind the radical change of heart and mind that was our only hope of peace at a time of desperate danger. Only one small problem remained. I must find a way to convert the world to my way of thinking.

There are three reasons, . . . apart from scientific considerations, mankind needs to travel in space. The first . . . is garbage disposal; we need to transfer industrial processes into space so that the earth may remain a green and pleasant place for our grandchildren to live in. The second . . . to escape material impoverishment: the resources of this planet are finite, and we shall not forego forever the abundance of solar energy and minerals and living space that are spread out all around us. The third . . . our spiritual need for an open frontier.

The technologies which have had the most profound effects on human life are usually simple. A good example of a simple technology with profound historical consequences is hay. Nobody knows who invented hay, the idea of cutting grass in the autumn and storing it in large enough quantities to keep horses and cows alive through the winter. All we know is that the technology of hay was unknown to the Roman Empire but was known to every village of medieval Europe. Like many other crucially important technologies, hay emerged anonymously during the so-called Dark Ages.