Warren Buffett: Important and knowable 

“We try to think about things that are both important and knowable. There are important things that are not knowable…. And there are things that are knowable, but not important — and we don’t want to clutter up our minds with those. We ask ourselves: ‘What’s important and knowable?’… There are all kinds of important subjects that Charlie and I don’t know anything about. And therefore, we don’t think about ’em. Our view about what the world will look like over the next 10 years in business or the state of U.S. competitiveness – we’re just no good [at that].”

—Warren Buffett (1998 Berkshire Hathaway Annual Meeting, via Outstanding Investor Digest.