I have lived with the prospect of an early death for the last 49 years. I'm not afraid of death, but I'm in no hurry to die. I have so much I want to do first. I regard the brain as a computer which will stop working when its components fail. There is no heaven or afterlife for broken down computers; that is a fairy story for people afraid of the dark.

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Keeping an active mind has been vital to my survival, as has been maintaining a sense of humor.

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Equations are just the boring part of mathematics. I attempt to see things in terms of geometry.

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The wise never marry, and when they marry they become otherwise.

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If what we regard as real depends on our theory, how can we make reality the basis of our philosophy? But we cannot distinguish what is real about the universe without a theory. It makes no sense to ask if it corresponds to reality, because we do not know what reality is independent of a theory.

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Quiet people have the loudest minds.

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The laws of physics demand the existence of something called ‘negative energy’.

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I'm happy if I have added something to our understanding of the universe.

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We are in danger of destroying ourselves by our greed and stupidity. We cannot remain looking inwards at ourselves on a small and increasingly polluted and overcrowded planet.

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I have experimental evidence that time travel is not possible.

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