Having it roots in Plato’s idealistic philosophy, it is a view that there are a limited number of fixed types in nature and thus that any variation is an illusion. A focus on central tendencies such as means to the neglect of standard deviations represents a modern form of typological thinking, as do racism and sexism. It was Darwin’s theory of natural selection that replaced typological thinking with population thinking.
See Ecological fallacy, Eugenics, Metonymy, Normality, Population thinking, Race-ethnicity, Theory of natural selection