Stock prices are likely to be among the prices that are relatively vulnerable to purely social movements because there is no accepted theory by which to understand the worth of stocks....investors have no model or at best a very incomplete model of behavior of prices, dividend, or earnings, of speculative assets.

Money management has been a profession involving a lot of fakery - people saying they can beat the market, and they really can't.

A major boom in real stock prices in the US after Black Tuesday brought them halfway back to 1929 levels by 1930. This was followed by a second crash, another boom from 1932 to 1937, and a third crash. Speculative bubbles do not end like a short story, novel, or play. There is no final denouement that brings all the strands of a narrative into an impressive final conclusion. In the real world, we never know when the story is over.

Economists who adhere to rational-expectations models of the world will never admit it, but a lot of what happens in markets is driven by pure stupidity - or, rather, inattention, misinformation about fundamentals, and an exaggerated focus on currently circulating stories.

In the longer run and for wide-reaching issues, more creative solutions tend to come from imaginative interdisciplinary collaboration.

The good news is that, at least in economics, I've seen movement away from its overemphasis on mathematical models of purely rational behavior to a more eclectic and commonsense approach: research that is, among other things, more respectful of insights from psychology.

It amazes me how people are often more willing to act based on little or no data than to use data that is a challenge to assemble.