Abstract
A serviceable account of unity is needed which can capture the idea that matter–form compounds are more unified than other types of composite entities (e.g., heaps, collections, or mereological sums). This chapter develops a conception of unity according to which a structured whole derives its unity from the way its parts interact with other parts to allow the whole and its parts to manifest their “team-work”-requiring capacities. With this conception of unity in place, interesting differences emerge between paradigmatic matter–form compounds belonging to natural (e.g., physical, chemical, or biological) kinds and composite entities belonging to social kinds, in particular artifacts. In the latter case, the interactional dependencies that connect the components of a system can be traced to mind-dependent factors that are extrinsic or external to the system in question, viz., the mental states of intentional agents who invent, design, produce, or use an artifact.