A General Concept of Being a Part of a Whole

The transitivity of the relation of part to whole is often questioned. But it is among the most basic principles of mereology. In this paper we present a general solution to the problem of transitivity of parthood which may be satisfactory for both its advocates and its opponents. We will show that even without the transitivity of parthood one can define—basic in mereology—the notion of being a mereological sum of some objects. We formulate several proposals of general approaches to the concept of being a part of a whole, none of which contains any existential assumptions. By adding the transitivity of parthood we obtain an axiomatization of “existentially neutral” (or “nonexistential”) mereology.