AI without validation is too unreliable to be of use in any serious application.

Most investors, of course, have not made the study of business prospects a priority in their lives. If wise, they will conclude that they do not know enough about specific businesses to predict their future earning power. I have good news for these non-professionals: The typical investor doesn't need this skill. ... The goal of the non-professional should not be to pick winners – neither he nor his "helpers" can do that – but should rather be to own a cross-section of businesses that in aggregate are bound to do well. A low-cost S&P 500 index fund will achieve this goal.

Many people talk about a willingness to have failures. I hate failures. I don't think you should strike to make failures. I think it's OK to make mistakes – but by the time they become real failures, you probably should have discovered them much earlier.

I didn’t realize that scientists were like that, and that people were like that. I would have thought — and I like to hope — that I encourage people rather than discourage people. I think you can say no and still say, “Boy, that might be a tough problem, but if you really work at it maybe you’ll solve it,” rather than, “No, it will never happen.”

What I want to do this morning is share with you a couple of stories and talk about a different Africa. Already this morning there were some allusions to the Africa that you hear about all the time: the Africa of HIV/AIDS, the Africa of malaria, the Africa of poverty, the Africa of conflict, and the Africa of disasters. While it is true that those things are going on, there's an Africa that you don't hear about very much. And sometimes I'm puzzled, and I ask myself why. This is the Africa that is changing, that Chris alluded to. This is the Africa of opportunity. This is the Africa where people want to take charge of their own futures and their own destinies.