Kinds of Biological Individuals: Sortals, Projectibility, and Selection

Individuality is an important concept in biology, yet there are many non-equivalent criteria of individuality expressed in different kinds of biological individuals. This article evaluates these different kinds in terms of their capacity to support explanatory generalizations over the systems they individuate. Viewing the problem of individuality from this perspective promotes a splitting strategy in which different kinds make different epistemic trade-offs that suit them for different explanatory roles. I argue that evolutionary individuals, interpreted as forming a functional kind, face difficulties of individuation and explanatory power that are mitigated by relying on more structurally based properties and non-evolutionary kinds. 1. Introduction2. Kinds of Biological Individuals3. Evolutionary Individuals and Functional Kinds4. Evolutionary versus Non-evolutionary Kinds of Individuals 4.1. Physiological individuality4.2. Ecological individuality4.3. Developmental individuality5. Conclusion