Christabel Cane
University College London
This paper builds upon Heller’s (1984) argument for temporal perdurantism, the view that:
a) Ordinary objects do not wholly exist at any one instant of time. Rather, they exist as partial instantiations (or temporal parts) of the object at every time at which the object exists.
b) These temporal parts are distinct: no one part is identical to another.
Heller demonstrates that a perdurance model of persistence solves the mereological problem of change: when an object’s spatial parts are gained or lost, temporal parts explain how the object can persist through this change. van Inwagen objects that perdurantism is unable to accommodate the intuition that ordinary objects might have existed for shorter or longer durations than they actually do, without endorsing Lewisian counterpart theory. His arguments runs as follows. If Descartes, say, is a fusion of his temporal parts, these parts must be essential to him. Descartes must therefore be constituted by these (and only these) parts in every possible world within which he resides. According to van Inwagen, we can only make sense of the claim that Descartes could have lived for a longer lifespan by stipulating that a counterpart of his does so. This means that a perdurantist who rejects counterpart theory is committed to the unfortunate conclusion that Descartes could not have lived for a longer or shorter period than his actual 54-year lifespan.
This paper will offer a modal analysis which allows the perdurantist to stipulate that some objects have temporal parts of varying lengths within multiple different possible worlds. I call this view modal perdurantism. It is the conjunction of the claims that:
a’) Ordinary objects do not wholly exist within any one possible world. Rather, they exist as partial instantiations (or modal parts) of the object within every world within which the object exists.
b’) These modal parts are distinct: no one part is identical to another, but they are all related by the co-parthood relation.
I’ll take Heller’s original principles as my guide, applying the method he uses to solve the problem of change to van Inwagen’s analogous problem: just as a difference in spatial parts over time requires a theory of temporal parts, so a difference in temporal parts across worlds requires that this theory be supplemented with modal parts.
Chair: Clelia Repetto
Time: September 12th, 10:00 – 10:30
Location: HS E.002
SOPhiA 2026 