Optimism is a strategy for making a better future. Because unless you believe that the future can be better, it’s unlikely you will step up and take responsibility for making it so. If you assume that there’s no hope, you guarantee that there will be no hope. If you assume that there is an instinct for freedom, there are opportunities to change things, there’s a chance you may contribute to making a better world. The choice is yours.

We naturally assume that our mental structures are universal. But I suppose an outside biologist looking at us would see something very different. He would see that, like other organisms, we have a narrow sphere within which we are very good, but that sphere is very limited. And that, in fact, the very achievements we can have within that sphere are related to lack of achievements in other spheres.

The human digestive and visual systems did clearly evolve over a very long period.

So, at one extreme you have indigenous, tribal societies trying to stem the race to disaster. At the other extreme, the richest, most powerful societies in world history, like the United States and Canada, are racing full-speed ahead to destroy the environment as quickly as possible.

In fact, when drugs are legalized, use sometimes goes down, it's been claimed. Part of the reason is that teenage kids use illicit drugs because they are illicit. They are thumbing their noses at society. If they were legal, they might not.

United States has comparative advantage in military force. It tends to react to anything at first with military force, that's what it's good at. And I think they overdid it. There was more military force than was necessary.

Science talks about very simple things, and asks hard questions about them. As soon as things become too complex, science can't deal with them... But it's a complicated matter: Science studies what's at the edge of understanding, and what's at the edge of understanding is usually fairly simple. And it rarely reaches human affairs. Human affairs are way too complicated.