A director who gets $150,000 per year from a company and needs the money is not independent.

[In picking stocks] You really have to know a lot about business. You have to know a lot about competitive advantage. You have to know a lot about the maintainability of competitive advantage. You have to have a mind that quantifies things in terms of value. And you have to be able to compare those values with other values available in the stock market.

If you have competence, you pretty much know its boundaries already. To ask the question (of whether you are past the boundary) is to answer it.

It's very useful to have a good grasp of all the big ideas in hard and soft science. A, it gives perspective. B, it gives a way for you to organize and file away experience in your head, so to speak.

I regard it as very unfair, but capitalism without failure is like religion without hell.

You need a different checklist and different mental models for different companies. I can never make it easy by saying, 'Here are three things.' You have to derive it yourself to ingrain it in your head for the rest of your life.

Is anyone really surprised that Warren, who is the ultimate embodiment of concentrated decision-making power, picked somebody [Bill and Melinda Gates] who he thinks is like him in many important ways? It was a noble and sensible decision.