In a low-density, chaotic network, ideas come and go. In the dense networks of the first cities, good ideas have a natural propensity to get into circulation. They spill over, and through that spilling they are preserved for future generations.
Connections also facilitate ideas. When humans first began to organize themselves into settlements, towns and cities, they became members of networks, which exposed them to new ideas and allowed them to spread their own discoveries. Before this happened, a novel idea by one person could well die with her, since she had no network to spread it to. Great ideas rise in crowds.
