Some people say Russia is running at 50 percent of its gross domestic product under that during the Communist period. In fact, none of the countries seems to have recovered the level that they had under communism, although the other countries in Eastern Europe are doing better than Russia and particularly the Czech Republic seems to be doing modestly well. East Germany I can't count because they have a rich uncle. You have economic benefits which have nothing to do with the workings of the system.

Usefulness depends on tractability.

I think that systems that are based on employment are illogical and attempts to meet them create all sorts of unnecessary complexities.

Evolutionary theory tends to explain quite well in retrospect how various species emerged. It's not very good on prediction. Nevertheless, one cannot say that there isn't a lot of knowledge that's been obtained in this field. In the same way, with these complex physical phenomena between solid state physics, you can say a lot of things without necessarily knowing the next step.

Vast ills have followed a belief in certainty.

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.

When you look at any experimental work not directly related to economics, but trying to test rational behavior in other ways, experiments have conspicuously failed to show rational behavior. Macro evidence certainly suggests deviations from rationality, but I don't want to say the rationality hypothesis is completely wrong. If you have any introspective idea or experimental idea about people's behavior, it seems to be incompatible with the really full scale rational expectations.