Martin Pickup

Leibniz has long faced a challenge about the coherence of the distinction between necessary and contingent truths in his philosophy. In this paper, I propose and examine a new way to save genuine contingency within a Leibnizian framework. I conclude that it succeeds in formally solving the problem, but at unbearable cost. I present Leibniz’s challenge by considering God’s choice of the best possible world (Sect. 2). God necessarily exists and necessarily chooses to actualise the best possible world. The actual world therefore could not be different, for if it were different it would be a distinct and inferior world and hence would not be created. In Sect. 3 I defend Leibniz from this challenge. I argue that while it is necessary for God to choose to create the best possible world, it is not necessary for any world to be the best possible. This is because the criterion for judging perfection can itself be contingent. Different criteria will judge different worlds as the best. Thus it is necessary for God to create the best, but not necessary which is the best. Distinguishing between possible worlds in Leibniz’s sense and in the modern sense allows a fuller exposition of this position. There are worries that can arise with the claim that the criterion of perfection is contingent. I consider two of the most pressing (Sect. 4). The first argues that the criterion is in God’s understanding and hence is necessary; the second alleges that a contingent criterion of perfection violates Leibniz’s cherished Principle of Sufficient Reason. These worries are well-grounded, and examining them reveals a deep incompatibility between this solution and Leibniz’s metaphysical views. I conclude that there is a real solution available, but that it is unacceptable to Leibniz or a Leibnizian. The search for a genuine solution that is genuinely Leibnizian goes on.

This paper constructs a model of metaphysical indeterminacy that can accommodate a kind of ‘deep’ worldly indeterminacy that arguably arises in quantum mechanics via the Kochen-Specker theorem, and that is incompatible with prominent theories of metaphysical indeterminacy such as that in Barnes and Williams (2011). We construct a variant of Barnes and Williams's theory that avoids this problem. Our version builds on situation semantics and uses incomplete, local situations rather than possible worlds to build a model. We evaluate the resulting theory and contrast it with similar alternatives, concluding that our model successfully captures deep indeterminacy.

This article aims to bring some work in contemporary analytic metaphysics to discussions of the Real Presence of Christ in the Eucharist. I will show that some unusual claims of the Real Presence doctrine exactly parallel what would be happening in the world if objects were to time-travel in certain ways. Such time-travel would make ordinary objects multiply located, and in the relevantly analogous respects. If it is conceptually coherent that objects behave in this way, we have a model for the behaviour of the Eucharist which shows the doctrine to be coherent, at least with respect to the issues discussed.

In this paper, I will offer an analogy between the Trinity and extended simples that supports a Latin approach to the Trinity. The theoretical tools developed to discuss and debate extended simples in the literature of contemporary analytic metaphysics, I argue, can help us make useful conceptual distinctions in attempts to understand what it could be for God to be Triune. Furthermore, the analogy between extended simples and the Trinity might surprise some who find one of these at least plausibly possible and the other incoherent.

Extended simples are fruitfully discussed in metaphysics. They are entities which are located in a complex region of space but do not themselves have parts. In this paper, I will discuss unextended complexes: entities which are not located at a complex region of space but do themselves have parts. In particular, I focus on one type of unextended complex: pointy complexes. Four areas are indicated where pointy complexes might prove philosophically useful. Unextended complexes are therefore philosophically fruitful, in much the same way as extended simples.

This paper outlines a novel solution to the Ship of Theseus puzzle. The solution relies on situations, a philosophical tool used in natural language semantics among other places. The core idea is that what is true is always relative to the situation under consideration. I begin by outlining the problem before briefly introducing situations. I then present the solution: in smaller situations the candidate is identical to Theseus’s ship. But in larger situations containing both candidates these identities are neither true nor false. Finally, I discuss some worries for the view that arise from the nature of identity, and suggest responses. It is concluded that the solution, and the theory that underpins it, are worth further investigation.

Indeterminacy in its various forms has been the focus of a great deal of philosophical attention in recent years. Much of this discussion has focused on the status of vague predicates such as ‘tall’, ‘bald’, and ‘heap’. It is determinately the case that a seven-foot person is tall and that a five-foot person is not tall. However, it seems difficult to pick out any determinate height at which someone becomes tall. How best to account for this phenomenon is, of course, a controversial matter. For example, some (such as Sorensen (2001) and Williamson (2002)) maintain that there is a precise height at which someone becomes tall and such apparent cases of indeterminacy merely reflects our ignorance of this fact. Others maintain that there is some genuine – and not merely epistemic – indeterminacy present is such cases and offer various accounts of how best to account for it. Supervaluationists (such as Keefe (2008)), for example, claim that the indeterminacy with respect to vague terms lies in their not having a single definite extension. Rather, each term is associated with a range of possible precise extensions or precisifications such that it is semantically unsettled which is the correct extension. One precisification of ‘tall’ might allow that anyone over five feet ten inches is tall, whereas another would only allow those over six foot to qualify; but no precisification will take someone who is five foot to be tall, and someone who is seven foot will count as tall on all precisifications. Thus – while someone who is seven foot will be determinately tall and someone who is five foot determinately not so – it will be indeterminate whether someone who stands at five foot eleven inches is tall. Yet, it is important to stress that putative cases of indeterminacy are not limited to vague predicates of this kind. Philosophers have invoked indeterminacy in discussions of topics as diverse as moral responsibility (Bernstein (forthcoming)), identity over time (Williams (2014)), and the status of the future (Barnes and Cameron (2009)). In this paper, we focus on two areas where discussion of various kinds of indeterminacy has been commonplace: physics and fiction. We propose a new model for understanding indeterminacy across these domains and argue that it has some notable advantages when compared to earlier accounts. Treating physics and fiction cases univocally also indicates an interesting connection between indeterminacy in these two areas.

Many philosophers have found change puzzling. How can it be that something changes in its properties and yet remains the same thing? How can one and the same thing have these different properties? Questions of this sort, about the persistence of things through change, have been an ongoing feature of philosophical discussion since the beginning of the discipline. I think that there is something puzzling here, and that investigating change can be a fruitful way of trying to understand a nest of connected issues concerning identity, time, tense, objects, properties, and instantiation. But not all agree. In some fairly recent papers, for instance, it has been argued that change is not problematic: there is nothing to be worried about. The phenomenon of change, it is suggested, is not one of particular philosophical interest, and we shouldn’t expect it to illuminate our wider discussion. As I have said, I think that change is problematic. I think it is initially mysterious how things can change. I believe working through the problem can tell us things about what the world is like, and thus that it is worthwhile doing so. In this paper I’ll defend the problem from the attempted dissolutions of it. In brief, my argument will be that what we are offered is not a real dissolution of the problem but rather an existing solution to the problem, namely adverbialism. This solution is not universally or even generally accepted. Pointing to a contested solution to a problem is doesn’t successfully dissolve that problem, so the problem of change is not successfully dissolved.

In this paper I propose a new solution to the problem of change: situationalism. According to this view, parts of reality fundamentally disagree about what is the case and reality as a whole is unsettled (i.e. metaphysically indeterminate). When something changes, parts of the world irreconcilably disagree about what properties it has. From this irreconcilable disagreement, indeterminacy arises. I develop this picture using situations, which are parts of possible worlds; this gives it the name situationalism. It allows a B-theory endurance view on which there is genuine incompatibility when things change. There are costs to the view, which are explored, but it is a novel approach which offers a distinct explanation of what happens when things exist through change.

There is a concern about the effectiveness of petitionary prayer. If I pray for something good, wouldn’t God give it to me anyway? And if I pray for something bad, won’t God refrain from giving it to me even though I’ve asked? This problem has received significant attention. The typical solutions suggest that the prayer itself can alter whether something is good or bad. I will argue that this is insufficient to fully address the problem, but also that the problem requires another assumption which can be doubted, thereby opening up a new way to solve the problem.

If something changes from being in one state to being in another state, when exactly does it change? And what’s going on at that time? These questions are often discussed under the heading of the ‘moment’ or ‘instant’ of change. In this paper, I will investigate a view on which there is an intrinsically distinguished, atomic time at which something changes, and at that time it is metaphysically indeterminate what is the case. The background metaphysical picture is situationalism, a theory on which reality is composed of irreducibly conflicting parts. These conflicting parts give rise to unsettledness in reality as a whole, and also at the point of change. I propose this view as a competitor for existing accounts of the time of change, and spell out a few reasons in its favour.

This paper concerns metaphysical indeterminacy and, in particular, the issue of whether quantum mechanics gives motivation for thinking the world contains it. In a previous paper (Darby G, Pickup M. Synthese 198:1685–1710, 2021), we have offered one way to think about metaphysical indeterminacy which we take to avoid some issues arising from certain features of quantum mechanics (such as the Kochen-Specker theorem). This approach has recently been criticised by Corti (Synthese, forthcoming), and we take this opportunity to respond. Our paper will therefore reply to Corti’s argument, but we also take it as a case study in ‘naturalistic metaphysics’ and hence to contribute to a more general discussion of the relationship between philosophy of science and analytic metaphysics.