There is a bit of a problem with the match between derivative securities markets and the primary markets. We have long ago instituted principles, essentially high margin requirements, to prevent certain instabilities in the stock market, and I think they're basically correct. The trouble is that there's a linkage, let's say, between something like the stock market and the index futures markets, and the fact that the margin requirements are very different, for example, played some role in the October '87 crash.
Kenneth ArrowOne way of looking at Impossibility Theorem is that we proposed some criteria for what a good system should be: what is it you want from a voting system, and impose some conditions. And then ask: can you have a voting system that guarantees that?
Kenneth ArrowThe Germans, for example, have some kind of compromise between single-member and broader districts. In Israel, you have nothing, you have only a national election. You have no local districts at all. And that's because of the idea that in addition to other ideological differences, locality matters. The question is does the congressman represent his district and the interests of his district? And as I said there's quite a variety of systems the democratic world. The implications need to be examined.
Kenneth ArrowOne thing I learned from meteorology is that being an actual science was no guarantee of exactness.
Kenneth ArrowI 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.
Kenneth Arrow