The wisdom of crowds comes not from the consensus decision of the
group, but from the aggregation of the ideas/thoughts/decisions of each
individual in the group.

At its simplest form, it means that if
you take a bunch of people and ask them (as individuals) to answer a
question, the average of each of those individual answers will likely
be better than if the group works together to come up with a single

[Also] diversity increases the quality of the
aggregated wisdom of the group. If you have too many people who are
alike, then no matter how smart they all are, they may not come up with
the same quality of answer than if you have less smart folks who have a
very different point of view. Diversity brings new information. And
that new information is valuable.

In order for the crowd to have wisdom, the crowd has to be made up of individuals who argue!

and independence are important because the best collective decisions
are the product of disagreement and contest, not consensus or
compromise. An intelligent group, especially when confronted with
cognition problems, does not ask its members to modify their positions
in order to let the group reach a decision everyone can be happy with.
Instead, it figures out how to use mechanisms–like market prices, or
intelligent voting systems–to aggregate and produce collective
judgements that represent now what any one person in the group thinks
but rather, in some sense, what they all think.”

“Paradoxically, the best way for a group to be smart is for each person in it to think and act as independently as possible.”