Shows how influence and network topology determine whether distributed belief formation approaches truth.
Agents update by repeatedly averaging their neighbors' beliefs, the DeGroot rule. Nobody reasons about where the information came from. The question is whether a large society still converges on the truth.
It does, and the condition is about the network rather than the agents: convergence holds when influence stays dispersed, so no individual keeps a share of total influence that fails to vanish as the society grows. One sufficiently listened-to node is enough to break it.
Homophily slows convergence without preventing it. Groups that mostly listen to themselves take longer to agree with the world.