It is change, continuing change, inevitable change, that is the dominant factor in society today. No sensible decision can be made any longer without taking into account not only the world as it is, but the world as it will be. This, in turn, means that our statesmen, our businessmen, our every man must take on a science fictional way of thinking.

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?

There is nothing so eternally adhesive as the memory of power.

When asked for advice by beginners. Know your ending, I say, or the river of your story may finally sink into the desert sands and never reach the sea.

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.

Science is uncertain. Theories are subject to revision; observations are open to a variety of interpretations, and scientists quarrel amongst themselves. This is disillusioning for those untrained in the scientific method, who thus turn to the rigid certainty of the Bible instead. There is something comfortable about a view that allows for no deviation and that spares you the painful necessity of having to think.

Uncertainty that comes from knowledge (knowing what you don't know) is different from uncertainty coming from ignorance.