Quantified Modal Logic and the Ontology of Physical Objects

In the present paper I aim at introducing a formal framework to deal with persistence and change of material objects in time. I first consider three main ontological theories: perdurantism ([6], [7], [16]), endurantism ([18]) and sequentialism ([2]); then develop a formal account for these theories, by making use of semantics for quantified modal logics: Kripke semantics ([3], [10]), the substantial interpretation ([5]) and counterpart semantics ([1]) respectively. I show that each interpretation soundly formalizes the corresponding ontological account, by referring to three features of these semantics: (i) the nature of individuals appearing in the domains of these structures, (ii) the principles on identity sound with respect to each account, (iii) the representation and solution of ontological problems within the logical frameworks. I conclude that Kripke semantics, the substantial interpretation and counterpart semantics are a sound formalization for perdurantism, endurantism and sequentialism respectively. Finally I outline some applications of these formalisms, in order to cope with the problem of comparing and reducing ontologies. By means of results in [4] and [9], I single out the necessary and sufficient conditions according to which an endurantist, a perdurantist and a sequentialist can meaningfully talk to each other. In the end I stress the role that logics in particular quantified modal logic can play in analysing ontological issues as persistence and change for material objects, thus improving our comprehension of the logical consequences of our ontological theses, and of the relationships among the various accounts. In the present paper I aim at introducing a formal framework to deal with the ontological issues of persistence and change for individuals in time. In the last years there has been a renewal of the debate on persistence conditions for physical objects; several proposals are available in the literature, which can be roughly divided into three main accounts. • Perdurantism (see Hawley [6], Heller [7], Sider [16]), according to which physical objects are extended in time as well as in space, with temporal parts formally analogous to spatial parts. • Endurantism (see Wiggins [18]), which maintains the alleged traditional account