If we start deciding, based on guesses or emotions, whether we will or won't participate in a business where we should have some long run edge, we're in trouble.

To invest successfully, you need not understand beta, efficient markets, modern portfolio theory, option pricing or emerging markets. You may, in fact, be better off knowing nothing of these. That, of course, is not the prevailing view at most business schools, whose finance curriculum tends to be dominated by such subjects. In our view, though, investment students need only two well-taught courses - How to Value a Business, and How to Think About Market Prices.

Emotional makeup is more important than technical skill

We try to exert a Ted Williams kind of discipline. In his book The Science of Hitting, Ted explains that he carved the strike zone into 77 cells, each the size of a baseball. Swinging only at balls in his "best" cell, he knew, would allow him to bat .400; reaching for balls in his "worst" spot, the low outside corner of the strike zone, would reduce him to .230. In other words, waiting for the fat pitch would mean a trip to the Hall of Fame; swinging indiscriminately would mean a ticket to the minors.

If you expect to continue to purchase stocks throughout your life, you should welcome price declines as a way to add stocks more cheaply to your portfolio.

When Berkshire buys common stock, we approach the transaction as if we were buying into a private business.

If this is a war, my side has the nuclear bomb. We have K Street. We have Wall Street. Debbie doesn't have anybody. I want a government that is responsive to the people who got the short straw in life.