 In the first role, selection is the generator and maintainer of the reliability of our senses and cognitive mechanisms, as well as the "fit" between those mechanisms and the world.In the second role, trial and error learning and the evolution of scientific theories are construed as selection processes.One of the hallmarks of evolutionary epistemology is the notion that empirical testing alone does not justify the pragmatic value of scientific theories but rather that social and methodological processes select those theories with the closest "fit" to a given problem.