- diversity of the members of the group,
- independent opinions of the group members, and
- a method for aggregation of the opinions.
Chapter 8 is devoted to science and how many widely spread scientists developing and criticizing various theories lead to explosive growth in our understanding. He also notes that this ideal world has its flaws as unknown researchers have a harder time selling their work than more established scientists.
I don't agree with all the conclusions drawn by Surowiecki but he does lay out what we need to do and not do to benefit from the pooled knowledge of a group. We can also draw lessons in computer science as computation and information gets more distributed that we need to integrate to find the best solutions we can.