Rationality is not just something you do so that you can make more money, it is a binding principle. Rationality is a really good idea. You must avoid the nonsense that is conventional in one's own time. It requires developing systems of thought that improve your batting average over time.

The name of the game is continuing to learn. Even if you're very well trained and have some natural aptitude, you still need to keep learning.

The big money is not in the buying and selling ... but in the waiting.

Clever derivatives broke dozens of companies. It killed them. Bankrupt. We don't need these kinds of innovation in finance. It's OK to be boring in finance. What we want is innovation in widgets.

Beta and modern portfolio theory and the like - none of it makes any sense to me.

There are two kinds of businesses: The first earns 12%, and you can take it out at the end of the year. The second earns 12%, but all the excess cash must be reinvested - there's never any cash. It reminds me of the guy who looks at all of his equipment and says, 'There's all of my profit.' We hate that kind of business.

People calculate too much and think too little.