Abstract

Organisms are indispensable objects in our everyday ontology and in biology. We know that counting particular lumps of living matter, and not others, allows us to describe and make predictions about evolutionary processes. Yet we lack a theory telling us which lumps to count. In some cases the answer is obvious; we find it easy to count piglets without worrying that we have confused parts of the mother with her babies. Yet once we turn to organisms which reproduce by tearing themselves in half (starfish) or growing copies of themselves at the ends of their limbs (plants) our intuitions desert us. Darwin’s Origin of the Species describes how the differential births and deaths of individuals produce evolutionary change. If we cannot decide how to count some creatures then we cannot apply our evolutionary theory to them. Do they fall outside of evolution then? Or is the intuitive organism really less obvious than we think? I present a novel definition of the organism which achieves a reconciliation of conflicting accounts by identifying a common functional effect of the mechanisms identified in those different accounts.