Without numerical fluency, in the part of life most of us inhibit, you are like a one-legged man in an ass-kicking contest.

Berkshire was built on the eternal verities: basic mathematics, basic horse sense, basic fear, and basic diagnosis of human nature to make predictions regarding human behavior. We stuck to the basics with a certain amount of discipline and it has worked out quite well.

The ethos of not fooling yourself is one of the best you could possibly have. It's powerful because it's so rare.

There's no way that you can live an adequate life without making many mistakes.

There’s no way that you can live an adequate life without many mistakes. In fact, one trick in life is to get so you can handle mistakes. Failure to handle psychological denial is a common way for people to go broke.

To us, investing is the equivalent of going out and betting against the pari-mutuel system. We look for a horse with one chance in two of winning, and that pays three to one. In other words, we're looking for a mispriced gamble. That's what investing is, and you have to know enough to know whether the gamble is mispriced.

Obviously, consideration of costs is key, including opportunity costs. Of course capital isn't free. It's easy to figure out your cost of borrowing, but theorists went bonkers on the cost of equity capital. They say that if you're generating a 100% return on capital, then you shouldn't invest in something that generates an 80% return on capital. It's crazy.