I think one of the things we learned from the physicists and also the theoretical biologists is the idea that when you're dealing with very complex systems you're going to get a large variety of behavior which can be interpreted as hill climbing, but hill climbing with a lot of modifications, hill climbing with big jumps occasionally.

Usefulness depends on tractability.

I'm struck by the fact that by and large equity capital doesn't play a big role in new financing; it's either bonds or internal financing but not really equity. And therefore, it's not clear that anything which improves the equity markets has really much to do with the productivity of the economy as a whole.

The trouble is that the risks that are being hedged very well by new financial securities are financial risks. And it appears to me that the real things you want to hedge are real risks, for example, risks in innovation. The fact is that you'd like companies to be able to take bigger chances. Presumably one obstacle to successful R&D, particularly when the costs are large, are the risks involved.

The intrinsic social structure, the family structure and so forth, is certainly in a very bad state. And I think that this is showing up in productivity. I think part of the reason, and I can't prove this, we're seeing a decline in some places is the breakup of the family, which is partly the result of an extreme form of individualism.

I don't believe that unemployment is all voluntary, by anticipation of future wage movements or this sort of thing. I know you can modify the models by taking into account the indivisibilities, but I don't really think that people are voluntarily unemployed.

I think one of the things we learned from the physicists and also the theoretical biologists is the idea that when you're dealing with very complex systems you're going to get a large variety of behavior which can be interpreted as hill climbing, but hill climbing with a lot of modifications, hill climbing with big jumps occasionally.