[niffe9]

To add the obligatory Buffett quote..
"It is better to be approximately right than precisely wrong."

Also, Gladwell's Blink seems to be very relevant to this discussion. He talks about how thin slicing can be more effective than people with more information in the examples of determining divorce, diagnosing heart attacks, hiring employees, etc. There are two things that Gladwell talk about that I think are important with investing. One is thin slicing exemplified with Buffett where he ignores the vast majority of information available to him. The other is snap judgements and the subconscious where experience investors like Soros thrive. He used to say he followed the "theory of reflexivity", but then later said that the theory was bogus and could be ignored. His son Robert said,

"My father will sit down and give you theories to explain why he does this or that. But I remember seeing it as a kid and thinking, Jesus Christ, at least half of this is [censored]. I mean, you know the reason he changes his position on the market or whatever is because his back starts killing him. It has nothing to do with reason. He literally goes into a spasm, and it's this early warning sign."