“There's always a moment when you start to fall out of love, whether it's with a person or an idea or a cause, even if it's one you only narrate to yourself years after the event: a tiny thing, a wrong word, a false note, which means that things can never be quite the same again.”

“I've heard an idea proposed, I've no idea how seriously, to account for the sensation of vertigo. It's an idea that I instinctively like and it goes like this. The dizzy sensation we experience when standing in high places is not simply a fear of falling. It's often the case that the only thing likely to make us fall is the actual dizziness itself, so it is, at best, an extremely irrational, even self-fulfilling fear. However, in the distant past of our evolutionary journey toward our current state, we lived in trees. We leapt from tree to tree. There are even those who speculate that we may have something birdlike in our ancestral line. In which case, there may be some part of our mind that, when confronted with a void, expects to be able to leap out into it and even urges us to do so. So what you end up with is a conflict between a primitive, atavistic part of your mind which is saying "Jump!" and the more modern, rational part of your mind which is saying, "For Christ's sake, don't!" In fact, vertigo is explained by some not as the fear of falling, but as the temptation to jump!”

“The world is a thing of utter inordinate complexity and richness and strangeness that is absolutely awesome. I mean the idea that such complexity can arise not only out of such simplicity, but probably absolutely out of nothing, is the most fabulous extraordinary idea. And once you get some kind of inkling of how that might have happened, it’s just wonderful. And … the opportunity to spend 70 or 80 years of your life in such a universe is time well spent as far as I am concerned.”

“For Children: You will need to know the difference between Friday and a fried egg. It's quite a simple difference, but an important one. Friday comes at the end of the week, whereas a fried egg comes out of a chicken. Like most things, of course, it isn't quite that simple. The fried egg isn't properly a fried egg until it's been put in a frying pan and fried. This is something you wouldn't do to a Friday, of course, though you might do it on a Friday. You can also fry eggs on a Thursday, if you like, or on a cooker. It's all rather complicated, but it makes a kind of sense if you think about it for a while.”

“All you really need to know for the moment is that the universe is a lot more complicated than you might think, even if you start from a position of thinking it's pretty damn complicated in the first place.”

“The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at or repair.”

“What I mean is that if you really want to understand something, the best way is to try and explain it to someone else. That forces you to sort it out in your own mind. And the more slow and dim-witted your pupil, the more you have to break things down into more and more simple ideas. And that’s really the essence of programming. By the time you’ve sorted out a complicated ideainto little steps that even a stupid machine can deal with, you’ve certainly learned something about it yourself. The teacher usually learns more than the pupil. Isn’t that true?”