ABSTRACT
I explore the challenges raised by biology for the metaphysical concept of individuality, and their consequences regarding biological identity. Descriptive metaphysics (in the sense of Peter Strawson), as the investigation of our major conceptual schemes, ties the individuality of X to the possibility to re-identify X. But many ascriptions of individuality in biology defy the notions of re-identifiability, persistence and discriminability that characterise individuality concepts in our inherited conceptual scheme. This chapter considers a more scientific metaphysics intending to capture biological individuality by a reference to the targets of selection, following David Hull. Yet I contrast this family of views to biologists’ recent focus on mutualisms within organisms. Individuality here appears rather as position in a “space of individuality” than as a binary concept defined by necessary and sufficient conditions. Accordingly, the chapter suggests thinking of biological individuals as ecosystems; this concurs with current research programmes using ecological approaches to address organisms and other purported biological individuals. I will then argue that the concept of individuality required to make sense of this suggestion is the notion of “weak individuality”, defined by a scheme for extracting, on the basis of probabilistic knowledge of interactions between elements (according to a given theory), the definition and boundaries of collective individuals.
