Peter Simons

I argue that the assumptions that physically basic things are either mereologically atomic, or that they are continuous and there are no atoms, both face difficult conceptual problems. Both views tend to presuppose a largely unquestioned assumption, that things have parts corresponding to the geometric parts of the regions they occupy. To avoid these problems I propose a third view, that physically simple things occupy a finite volume without themselves having parts. This view is examined enough to tease out some of its consequences and show that it withstands the obvious questions it faces. I conclude by mentioning some precedents for this view in Democritus, Kant, and Whitehead, with close variants in Boscovich, Harré, and Markosian.

Commonsense ontology contains both continuants and occurrents, but are continuants necessary? I argue that they are neither occurrents nor easily replaceable by them. The worst problem for continuants is the question in virtue of what a given continuant exists at a given time. For such truthmakers we must have recourse to occurrents, those vital to the continuant at that time. Continuants are, like abstract objects, invariants under equivalences over occurrents. But they are not abstract, and their being invariants enables us to infer both their lack of temporal parts and that non-invariant predications about them must be relativized to times. \\\ [Joseph Melia] In this paper I try to eliminate occurrents from our ontology. I argue against Simons' position that occurrents are needed to supply truthmakers for existential claims about continuants. Nevertheless, those who would eliminate occurrents still need some account of our willingness to assert sentences that logically entail their existence. Though it turns out to be impossible to paraphrase away our reference to occurrents, I show that the truthmakers for such sentences are facts that involve only continuants. This is enough to allow us to regard our ordinary talk about occurrents as fictional. Finally, I argue that a proper conception of the underlying temporal facts about continuants can both avoid the problematic tensed theory of time and the problem of temporary intrinsics.

What primitive concepts does formal ontology require? Forsaking as too indirect the linguistic way of discerning the categories of being, this paper considers what primitives might be required for representing things in themselves (noumena) and representations of them in a thoroughly crafted large autonomous multi-purpose database. Leaving logical concepts and material ontology aside, the resulting 32 categories in 13 families range from the obvious (identity/difference, existence/non-existence) through the fairly obvious (part/whole, one/many, sequential order) and the surprisingly familiar (illocutionary modes, mass/count, indexical/descriptive) to the controversial (moment/fundament, transparent/opaque) and the arcane (modes of class delimitation, taxonomic rank, aspects of designators). Any such list is speculative and tentative, but the test of this one will be in its implementation, a new departure for philosophical category theories.

Occurrents are entities that exist in time and, with few or no exceptions, extend over time as well, that is, they have parts corresponding to the different times at which they exist. This makes it very easy to say what makes it true that they exist at the times at which they do. Singular existential propositions, being contingent, positive and arguably atomic, stand in need of truth-makers, entities in virtue of whose existence they are true. The obvious candidate for what makes it true that Tony Blair exists is the Right Honourable Member for Sedgefield himself: by virtue of his existing, it is true that he exists. Nothing could be more straightforward. However, things that exist in time, with few exceptions, exist at some times and not at others. So a proposition to the effect that a certain object exists at a certain time likewise stands in need of a truth-maker, one matching the requirements of the existential proposition in question in its temporal specificity. Take an occurrent such as a boxing match and suppose it is going on twenty minutes after starting: by virtue of what is this true? The obvious answer here is that it is by virtue of the existence of that temporal part or phase which extends just over the time in question. Other temporal parts of the same occurrent which do not extend over this time do not act as truth-maker for the temporally specific existential proposition, this one does. There is no problem because occurrents do have temporal parts which can do this job.

Despite its lack of influence in analytical philosophy, and independently of its content as a process philosophy, Whitehead's system in Process and Reality affords a valuable lesson on how to pursue revisionary systematic metaphysics. This paper argues the case generally for metaphysical revision and system, describes the structure of Whitehead's categorial scheme, endorses his idea of an ultimate which is not an entity, and outlines an alternative, “digital” ultimate or basis composed of several analytical factors. [I]n the absence of a well-defined categoreal scheme of entities, issuing in a satisfactory metaphysical system, every premise in a philosophical argument is under suspicion.

I consider the idea of a propositional logic of location based on the following semantic framework, derived from ideas of Prior. We have a collection L of locations and a collection S of statements such that a statement may be evaluated for truth at each location. Typically one and the same statement may be true at one location and false at another. Given this semantic framework we may proceed in two ways: introducing names for locations, predicates for the relations among them and an “at” preposition to express the value of statements at locations; or introduce statement operators which do not name locations but whose truth-conditional effect depends on the truth or falsity of embedded statements at various locations. The latter is akin to Prior’s approach to tense logic. In any logic of location there will be some basic operators which we can define. By ringing the changes on the topology of locations, different logical systems may be generated, and the challenge for the logician is then in each case to find operators, axioms and rules yielding a proof theory adequate to the semantics. The generality of the approach is illustrated with familiar and not so familiar examples from modal, tense and place logic, mathematics, and even the logic of games. To the memory of Ted Dawson, who introduced me to philosophy and the writings of Arthur Prior.