I don't subscribe to the thesis, 'Let the buyer beware,' I prefer the disregarded one that goes, 'Let the seller be honest.'

The young specialist in English Lit, ...lectured me severely on the fact that in every century people have thought they understood the Universe at last, and in every century they were proved to be wrong. It follows that the one thing we can say about our modern "knowledge" is that it is wrong.

They absorb carbon monoxide and carbon dioxide and give out oxygen. What could be more desirable? And they look good in the bargain. Stop chopping down the rain forests and plant more saplings, and we're on our way.

It is the obvious which is so difficult to see most of the time. People say 'It's as plain as the nose on your face.' But how much of the nose on your face can you see, unless someone holds a mirror up to you?

I'm gradually managing to cram my mind more and more full of things. I've got this beautiful mind and it's going to die, and it'll all be gone. And then I say, not in my case. Every idea I've ever had I've written down, and it's all there on paper. And I won't be gone; it'll be there.

Although we will hate and fight the machines, we will be supplanted anyway, and rightly so, for the intelligent machines to which we will give birth may, better than we, carry on the striving toward the goal of understanding and using the Universe, climbing to heights we ourselves could never aspire to.

It's humbling to think that all animals, including human beings, are parasites of the plant world.