In fact, what I usually say to people, “Probably some of the most successful scientists are the ones that know how to deal with failure well.” Because it’s easy to feel good when you succeed. That’s an easy thing. But you’re probably going to fail in science a lot more than you succeed, so you really have to learn how to deal with it and not let it beat you.

So Cambridge rejected me. Quite rightly, although at the time I thought it was a little churlish. So, I had to do it without any university training. ... and I began to realize that there were probably a lot more of these things, and that if you find these things, you get a position in the ladder which you can’t get to unless you have either got an education or something else. So by finding important things, you immediately get into the game, which you’d been excluded from otherwise.

My first mistake, of course, was in buying control of Berkshire. Though I knew its business - textile manufacturing - to be unpromising, I was enticed to buy because the price looked cheap. Stock purchases of that kind had proved reasonably rewarding in my early years, though by the time Berkshire came along in 1965 I was becoming aware that the strategy was not ideal. If you buy a stock at a sufficiently low price, there will usually be some hiccup in the fortunes of the business that gives you a chance to unload at a decent profit, even though the long-term performance of the business may be terrible. I call this the "cigar butt" approach to investing. A cigar butt found on the street that has only one puff left in it may not offer much of a smoke, but the "bargain purchase" will make that puff all profit. Unless you are a liquidator, that kind of approach to buying businesses is foolish.

I feel that because I challenge myself so often, sometimes I will fail. This is, to me, the essence of competition — that there will be both winners and losers. But I have great faith in myself that I will turn this loss into something positive.

So I find that teaching and the students keep life going, and I would never accept any position in which somebody has invented a happy solution for me where I don’t have to teach.  Never.

I don’t believe I can really do without teaching.  The reason is, I have to have something so that when I don’t have any ideas and I’m not getting anywhere I can say to myself, “At least I’m living; at least I’m doing something; I’m making some contribution”—it’s just psychological.

It is necessary, I believe, to accept this idea, not only for science, but also for other things; it is of great value to acknowledge ignorance.  It is a fact that when we make decisions in our life we don't necessarily know that we are making them correctly; we only think that we are doing the best we can – and that is what we should do.

Then there was Von Neumann, the great mathemati-cian. We used to go for walks on Sunday. We'd walk in the canyons, and we'd often walk with Bethe, and Von Neumann, and Bacher. It was a great pleasure. And Von Neumann gave me an interesting idea; that you don't have to be responsible for the world that you're in.

There was no importance to what I was doing, but ultimately there was.  The diagrams and the whole business that I got the Nobel Prize for came from that piddling around with the wobbling plate.

The first principle is that you must not fool yourself—and you are the easiest person to fool. So you have to be very careful about that. After you've not fooled yourself, it's easy not to fool other scientists. You just have to be honest in a conventional way after that.