We believe that almost all really good investment records will involve relatively little diversification. The basic idea that it was hard to find good investments and that you wanted to be in good investments, and therefore, you'd just find a few of them that you knew a lot about and concentrate on those seemed to me such an obviously good idea. And indeed, it's proven to be an obviously good idea. Yet 98% of the investing world doesn't follow it. That's been good for us.
Charlie MungerYou've got to have models in your head and you've got to array you experience - both vicarious and direct - onto this latticework of mental models.
Charlie MungerOf course the self-serving bias is something you want to get out of yourself. Thinking that what's good for you is good for the wider civilization and rationalizing all these ridiculous conclusions based on this subconscious tendency to serve one's self is a terribly inaccurate way to think.
Charlie MungerWe have never had the will to enforce the immigration laws. What you see is what you'll continue to get.
Charlie MungerThe ethical rule is from Samuel Johnson who believed that maintenance of easily removable ignorance by a responsible office holder was treacherous malfeasance in meeting moral obligation. The prudential rule is that underlying the old Warner & Swasey advertisement for machine tools: "The man who needs a new machine tool, and hasn't bought it, is already paying for it". The Warner & Swasey rule also applies, I believe, to thinking tools. If you don't have the right thinking tools, you, and the people you seek to help, are already suffering from your easily removable ignorance.
Charlie Munger