Population Thinking

German-American evolutionary biologist Ernst Mayr introduced the term in a 1959 essay written for the centennial of Darwin's On the Origin of Species. Mayr had been developing the contrast since 1955, pitting population thinking — which treats individual variation as the fundamental biological reality — against "typological thinking," the older Platonic view that a species is defined by an ideal type from which individuals merely deviate. He credited Darwin with displacing essentialism, arguing that this conceptual shift was as important as the theory of natural selection itself.