Improper Parts, Restricted Existence, and Use: Three Arguments against Ted Sider\u27s Four-Dimensionalism

This paper raises and defends three classes of objections to Ted Sider\u27s argument from vagueness in his recent work, Four-Dimensionalism. The first class argues that Sider\u27s case for four-dimensionalism is superfluous, that is, “mereologically promiscuous three-dimensionalists” can accept his argument yet maintain a compatible variety of three-dimensionalism that accepts the existence of temporal parts as improper parts of otherwise enduring wholes. Second, Sider\u27s argument begs the question of unrestricted composition by presupposing an unrestricted conception of objecthood that the three-dimensionalist can freely reject. Finally, Sider\u27s project offends ontology by undermining a deep ontological distinction between temporal existence and extension. Even assuming that any defense of this distinction will be circular, Sider\u27s account contradicts our commonsense and reflective thought concerning existence without sufficient reason to justify this revision. Since three-dimensionalism can preserve our distinctions in conjunction with granting existence to temporal parts, it is to be preferred