Nathaniel Gan

According to the mereological view of spacetime emergence, spacetime emerges from non-spatiotemporal fundamental entities in the sense that the latter compose the former. Some authors object to the mereological view on the grounds that our mereology of physical objects is closely associated with certain locative principles, which non-spatiotemporal entities cannot satisfy because they lack location. This paper argues that the mereological view can be defended by turning to mereotopology, which supplements mereology with a theory of connection. A mereotopological theory will be proposed for physical entities, which includes analogues of the locative principles and a bridge principle relating connection with location. It is shown that our theory of location can be derived from the proposed mereotopological theory via the bridge principle. On a mereotopological view of spacetime emergence, therefore, the locative principles hold in some sense between non-spatiotemporal entities, and location emerges from the fundamental connection relation.

We sometimes reason about logically incomplete sets of information that we take to resemble particular aspects of our world while differing from those aspects by being incomplete. This paper argues that there is a tension in this usual way of thinking about incompleteness: insofar as we take incomplete worlds to resemble ours, we have less grounds on which to assume that our world is logically complete. It is argued that the tension can be resolved by revising our notion of completeness. We may think of completeness, not as an absolute property that a world may have independently of other worlds, but as a relative property that worlds may have in relation to each other. The proposed relative notion preserves some of our usual ways of thinking about completeness and allows parallels to be drawn between the properties of logical completeness and logical consistency. A relative view of completeness has implications for attempts to align incomplete worlds with ours, and for the way we model our reasoning about incompleteness.

Griefbots are digital representations of deceased individuals intended to replicate some aspect of their agential behaviour. It has been suggested that griefbots allow the represented individuals to survive death in some sense, but this possibility disagrees with popular theories of survival in the philosophical literature. This paper proposes a theory of survival that is consistent with the possibility of digital survival while maintaining plausibility in the sense of aligning with familiar theories in other cases. A degree-based private conativist theory of survival is proposed, on which the survival relation admits of degrees, and the degree to which survival obtains relative to each person depends on their person-tracking attitudes. On the proposed theory, griefbots afford survival insofar as they preserve the represented individual’s social relationships and people organise their person-tracking attitudes around this social continuity. Compared to alternative theories, the proposed theory more straightforwardly accounts for observed engagement patterns with griefbots.

Fictionalism about a kind of disputed object is often motivated by the fact that the view interprets discourse about those objects literally without an ontological commitment to them. This paper argues that this motivation is inadequate because some viable alternatives to fictionalism have similar attractions. Meinongianism—the view that there are true statements about non-existent objects—is one such view. Meinongianism bears significant similarity to fictionalism, so intuitive doubts about its viability are difficult to sustain for fictionalists. Moreover, Meinongianism avoids some of fictionalism’s weaknesses, thus it is even preferable to fictionalism in some respects.

Some artificial intelligence systems attempt to implement counterfactual reasoning using computer simulations. But differences between the logics of counterfactuals and simulations suggest that the reliability of simulation as a means of counterfactual reasoning may be limited. On the usual understanding of counterfactuals, ‘If a vehicle had decelerated, snow would have been white’ is true, and the actual world factors into the evaluation of counterfactuals with true antecedents. But we would expect ‘In a simulation of a decelerating vehicle, snow would be white’ to be false, and for the actual world not to factor into our consideration of what happens in simulations with true stipulations. This paper formulates a logic to model simulation-based reasoning and identifies necessary conditions for the logics of counterfactuals and simulations to align. The investigations imply that simulation-based artificial systems can reliably implement counterfactual reasoning only insofar as it has an adequate notion of similarity between worlds, relevance between propositions, and compatibility between stipulations. Implications for the prospects of simulation-based artificial intelligence are discussed.

Fictionalists about a kind of disputed entity aim to give a face-value interpretation of our discourse about those entities without affirming their existence. The fictionalist’s commitment to non-realism leaves open three options regarding their ontological position: they may deny the existence of the disputed entities (anti-realism), remain agnostic regarding their existence (agnosticism), or deny that there are ontological facts of the matter (ontological anti-realism). This paper outlines a method of adjudicating between these options and argues that fictionalists may be expected to hold preferences between them. The typical arguments and motivations for fictionalism lead naturally to a practice-based metaontological framework under which our practices regarding a kind of disputed entity might inform our ontological beliefs about those entities. When that framework is applied to fictionalism, it is found that the usual motivations for fictionalism lead naturally, though not decisively, to ontological anti-realism. And, where there are reasons against ontological anti-realism, fictionalism leans more toward anti-realism than agnosticism.

According to the Quine-Putnam indispensability argument (QPIA), we should be realists about mathematics because mathematics is indispensable to science. QPIA’s reasoning can be understood in two ways. Under the confirmational analysis, QPIA argues that mathematics is confirmed as part of our best scientific theories. Under the pragmatic analysis, QPIA argues that our scientific practices implicitly assume the truth of mathematics. The usual reasons given in favour of the pragmatic analysis are that it affords advantages to proponents of QPIA by avoiding some dependencies of the confirmational analysis. This paper argues that these reasons are indecisive, because the pragmatic analysis introduces some dependencies of its own. Nevertheless, the paper also argues, there are other reasons to prefer the pragmatic analysis. QPIA is an instance of a wider class of realist arguments—indispensability arguments—and the pragmatic analysis yields a preferable overall understanding of indispensability arguments than does the confirmational analysis.

Call the epistemological grounds on which we rationally should determine our ontological (or alethiological) commitments regarding an entity its arbiter of existence (or arbiter of truth). It is commonly thought that arbiters of existence and truth can be provided by our practices. This paper argues that such views have several implications: (1) the relation of arbiters to our metaphysical commitments consists in indispensability, (2) realist views about a kind of entity should take the kinds of practices providing that entity’s arbiters to align with respect to their metaphysical dependencies, (3) if realists take a kind of practice to provide grounds on which to affirm the existence of a kind of entity, they should turn to those same grounds when seeking to provide an epistemology of the relevant domain.

This paper examines ten possible topological interpretations of connection and for each interpretation, identifies sufficient conditions under which a significant class of topological spaces provides models of General Extensional Mereotopology with Closure Conditions (GEMTC) in which some key mereotopological ideas align with their topological analogues. In particular, there is an interpretation under which the non-empty sets of any symmetric topology are a model of GEMTC with alignment between the mereotopological and topological definitions of (self-)connection, open and closed entities, interior, exterior, closure, and boundary.

Fictionalism about a kind of disputed object is often motivated by the fact that the view interprets discourse about those objects literally without an ontological commitment to them. This paper argues that this motivation is inadequate because some viable alternatives to fictionalism have similar attractions. Meinongianism—the view that there are true statements about non-existent objects—is one such view. Meinongianism bears significant similarity to fictionalism, so intuitive doubts about its viability are difficult to sustain for fictionalists. Moreover, Meinongianism avoids some of fictionalism’s weaknesses, thus it is even preferable to fictionalism in some respects.

There are two ways of approaching an ontological debate: ontological realism recommends that metaphysicians seek to discover deep ontological facts of the matter, while ontological anti-realism denies that there are such facts; both views sometimes run into difficulties. This paper suggests an approach to ontology that begins with conceptual analysis and takes the results of that analysis as a guide for which metaontological view to hold. It is argued that in some cases, the functions for which we employ a part of our conceptual scheme might give us reasons to posit ontological facts regarding certain objects. The proposed approach recommends ontological realism about an object just in case our conceptual scheme gives us reason to. This yields a mixed overall metaontological view that adopts ontological realism to some issues and ontological anti-realism to others, and that avoids the difficulties that typically arise for the two views.

This paper examines several intended topological features of the Region Connection Calculus (RCC) and argues that they are either underdetermined by the formal theory or given by the complement axiom. Conditions are identified under which the axioms of RCC are satisfied in topological models under various set restrictions. The results generalise previous results in the literature to non-strict topological models and across possible interpretations of connection. It is shown that the intended interpretation of connection and the alignment of self-connection with topological connection are underdetermined by the axioms of RCC, which suggests that additional axioms are necessary to secure these features. It is also argued that the complement axiom gives RCC models much of their topological structure. In particular, the incompatibility of RCC with interiors is argued to be given by the complement axiom.

In ontological debates, realists typically argue for their view via one of two approaches. The _Quinean approach_ employs naturalistic arguments that say our scientific practices give us reason to affirm the existence of a kind of entity. The _Fregean approach_ employs linguistic arguments that say we should affirm the existence of a kind of entity because our discourse contains reference to those entities. These two approaches are often seen as distinct, with _indispensability arguments_ typically associated with the former, but not the latter, approach. This paper argues for a connection between the two approaches on the grounds that the typical arguments of the Fregean approach can be reformulated as indispensability arguments. This connection is significant in at least two ways. First, it implies that indispensability arguments provide a common framework within which to compare the Quinean and Fregean approaches, which allows for a more precise delineation of the two approaches. Second, it implies the possibility of analogical relations that allow proponents and opponents of each approach to draw upon the ideas that have been developed regarding the other.