What separates us from the rest of our non-human mutant ancestors? Collective intelligence brings together fragments of knowledge to create a fostered generation of urbanites and traders. Density brings specialized people together whom never know that they are so closely defined by the miles that actually separate them. Exchange started in Africa:

The process of cumulative innovation that has doubled life span, cut child mortality by three-quarters and multiplied per capita income ninefoldaworld-wideain little more than a century is driven by ideas having sex. And things like the search engine, the mobile phone and container shipping just made ideas a whole lot more promiscuous still.

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