There's a lot of randomness in the decisions that people make.

Intuitive diagnosis is reliable when people have a lot of relevant feedback. But people are very often willing to make intuitive diagnoses even when they're very likely to be wrong.

Optimistic people play a disproportionate role in shaping our lives. Their decisions make a difference; they are inventors, entrepreneurs, political and military leaders - not average people. They got to where they are by seeking challenges and taking risks.

Policy makers, like most people, normally feel that they already know all the psychology and all the sociology they are likely to need for their decisions. I don't think they are right, but that's the way it is.

We think, each of us, that we're much more rational than we are. And we think that we make our decisions because we have good reasons to make them. Even when it's the other way around. We believe in the reasons, because we've already made the decision.

If people do not know what is going to make them better off or give them pleasure, then the idea that you can trust people to do what will give them pleasure becomes questionable.