In the popular imagination, groups tend to make people either dumb or crazy, or both. The speculator Bernard Baruch, for instance, famously said: “Anyone taken as an individual is tolerably sensible and reasonable—as a member of a crowd, he at once becomes a blockhead.” Henry David Thoreau lamented: “The mass never comes up to the standard of its best member, but on the contrary degrades itself to a level with the lowest.” Friedrich Nietzsche wrote, “Madness is the exception in individuals but the rule in groups,” while the English historian Thomas Carlyle put it succinctly: “I do not believe in the collective wisdom of individual ignorance.”
“…..the four conditions that characterize wise crowds: diversity of opinion (each person should have some private information, even if it’s just an eccentric interpretation of the known facts), independence (people’s opinions are not determined by the opinions of those around them), decentralization (people are able to specialize and draw on local knowledge), and aggregation (some mechanism exists for turning private judgments into a collective decision).”
– from The Wisdom of Crowds by James Surowieck
