Material objects in tile space -time
This dissertation contains four chapters, each of which is concerned with issues related to the metaphysics of material objects and the possibility of space-time with a certain kind of structure. In the first chapter, I present and evaluate a philosophical argument for the claim that space-time could be tiled, that is, composed of atomic regions every one of which is extended. Some physicists suggest that our best scientific theories entail that space-time is tiled. However, modal recombination principles might also support the possibility of tiled space-time. I evaluate this latter defense of the possibility of tiled space-time and find it inconclusive. Nevertheless, I think we should take seriously the possibility that space-time is tiled.
In the second chapter, I consider a recent debate about the nature of material simples, that is, objects that have no proper parts. According to occupancy accounts of the nature of simples, an object is a simple in virtue of the kind of region it occupies. Some occupancy accounts are compatible with the possibility of simples in tiled space-time and others are not. One such occupancy account is weaker than all the others in the following sense: everything that is counted as a simple according to any of the other major occupancy accounts is counted as a simple according to this weak account. So, certain counterexamples to the weakest occupancy account will also be a counterexample to all the others. I present these counterexamples and formulate new accounts that are immune to them.
In chapter three I introduce a new problem in the debate about the nature of simples. Some philosophers have presented views on which material simples can be heterogeneous, for instance, have purple and white stripes. Unfortunately, most of these metaphysical views assume that extended simples occupy non-tiled space-time. I explore various ways in which extended simples could be heterogeneous while occupying tiled space-time.
In chapter four I consider a novel defense of a doctrine of temporal parts against a paradox of undetached parts. According to the paradox, if Descartes had died abruptly exactly one year before his actual death, then it seems that he would have occupied the same region as one of his proper temporal parts. According to the novel response, both Descartes and his proper part would have occupied smaller regions in the counterfactual circumstance. This response seems to have several benefits that traditional responses lack, but is threatened by the possibility of space-time with a tiled structure. I show how one might plausibly maintain the novel response while accepting that space-time might be tiled.