Abstract

The problem of defining the self has traditionally been conceived as a task for philosophers. However, the development of immunology in the second part of the 20th century has led many scientists to conclude that immunology is the science of the self. This led to two different approaches to biological individuality: physiological individuation that is mostly concerned with organisms seen as strongly cohesive and unified metabolic entities, and evolutionary individuation where evolution by natural selection is seen as the best framework for individuating biological entities. I discuss physiological approaches to biological individuation with a special focus on the immunological theories of the self. I argue that the immunological theories can only function as vague metaphors that do not provide a valid criterion for individuating organisms in biology.