 In these diffusion/contagion models, though, the individuals do not gather evidence from the world, share evidence with each other, or form beliefs in any sort of rational way. For this reason, philosophers of science have tended to use the network epistemology framework instead. This framework was introduced by economists Bala and Goyal (1998) to model how individuals learn from neighbors. It was imported to philosophy by Kevin Zollman, who first used it to represent scientific communities (Zollman 2007, 2010).