 "Evolutionary epistemology" can also refer to a theory that applies the concepts of biological evolution to the growth of human knowledge and argues that units of knowledge themselves, particularly scientific theories, evolve according to selection.In that case, a theory, like the germ theory of disease, becomes more or less credible according to changes in the body of knowledge surrounding it.Evolutionary epistemology is a naturalistic approach to epistemology, which emphasizes the importance of natural selection in two primary roles.