The question of whether Everettian quantum mechanics (EQM) justifies the existence of metaphysical indeterminacy has recently come to the fore. Metaphysical indeterminacy has been argued to emerge from three sources: coherent superpositions, the indefinite number of branches in the quantum multiverse and the nature of these branches. This paper reviews the evidence and concludes that those arguments don’t rely on EQM alone and rest on metaphysical auxiliary assumptions that transcend the physics of EQM. We show how EQM can be ontologically (...) interpreted without positing metaphysical indeterminacy by adopting a deflationary attitude towards branches. Two ways of developing the deflationary view are then proposed: one where branches are eliminated, and another where they are reduced to the universal quantum state. (shrink)

One might suppose that Everettian quantum mechanics (EQM) is inhospitable to metaphysial indeterminacy (MI), given that, as A. Wilson (2020) puts it, "the central idea of EQM is to replace indeterminacy with multiplicity" (77). But as Wilson goes on to suggest, the popular decoherence-based understanding of EQM (henceforth: DEQM) appears to admit of indeterminacy in both world number and world nature, where the latter indeterminacy---our focus here---is plausibly metaphysical. After a brief presentation of DEQM (S1), we bolster the case for (...) there being MI in world nature in DEQM (S2). The remainder of the paper is devoted to a comparative assessment of the two main approaches to MI for purposes of accommodating this MI---namely, a metaphysical supervaluationist approach (as per Barnes and Williams 2011) and a determinable-based approach (as per Wilson 2013 and Calosi and Wilson 2018 and 2021). We briefly describe each approach (S3), then offer arguments in favour of a determinable-based approach to world nature MI in DEQM (S4). (shrink)

Metaphysical indeterminacy in the context of quantum mechanics is often motivated by the eigenstate-eigenvalue link. However, the sparse view of Glick illustrates why it has no such implications. Other links connecting quantum states and property ascriptions—such as those associated with the GRW theory—may introduce indeterminacy, but such indeterminacy may be viewed as merely representational and is susceptible to familiar treatments of vagueness. Thus, I contend that such links fail to provide a compelling motivation for quantum metaphysical indeterminacy.

Most believe that it is worse for a person to die than to continue to exist with a good life. At the same time, many believe that it is not worse for a merely possible person never to exist than to exist with a good life. I argue that if the underlying properties that make us the sort of thing we essentially are can come in small degrees, then to maintain this commonly-held pair of beliefs we will have to embrace (...) an implausible sort of evaluative hypersensitivity to slight nonevaluative differences. Avoidance of such hypersensitivity pressures us to accept that it can be worse for merely possible people never to exist. If this conclusion is correct, then the standard basis for giving no or less priority to merely possible persons would disappear (i.e., that things cannot be better or worse for them). Though defenders of Person-Affecting Views and their opponents may still disagree in theory, they could arrive at the same answers to many monumentally important practical questions. (shrink)

One important challenge for contingentists is that they seem to be unable to account for the meaning of some apparently meaningful modal discourse that is perfectly intelligible for necessitists. This worry is particularly pressing for higher-order contingentists, contingentists who hold that it is not only contingent which objects there are, but also contingent which semantic values there are for higher-order variables to quantify over. Objections against higher-order contingentism along these lines have been presented in Williamson (Mind 119(475):657–748, 2010; Modal logic (...) as metaphysics, Oxford University Press, 2013, ch. 7), and Fritz and Goodman (Mind 126(504):1063–1108, 2017). This paper presents a way for contingentists to respond to these challenges. The upshot is that the contingentist can account for the meaningfulness of the problematic modal claims by pretending necessitism to be true, but in some cases it turns out to be indeterminate whether they are true. I defend this strategy against the objections against pretence-strategies presented in Fritz and Goodman (Mind 126(504):1063–1108, 2017, §4). Furthermore, I defend the plausibility of the resulting indeterminacy from the contingentist’s perspective. (shrink)

One of the most popular and enduring approaches to indeterminacy phenomena (e.g., vagueness) over the past several decades has been some form or another of supervaluationism. I argue that supervaluationism is inadequate as a model of indeterminacy: There is an entire class of examples of indeterminacy, characterized by a common “branching” structure, that cannot be modeled in the way supervaluationism proposes. I demonstrate my conclusion explicitly with respect to two specific examples—indeterminate personal identity and indeterminate reference—showing how supervaluationism can model (...) neither. Importantly, my arguments apply to both traditional “semantic” and more recent “metaphysical” versions of supervaluationism. (shrink)

The aim of this essay is to argue that, if a robust form of moral realism is true, then moral vagueness is ontic vagueness. The argument is by elimination: I show that neither semantic nor epistemic approaches to moral vagueness are satisfactory.

According to Sider, a question is metaphysically substantive just in case it has a single most natural answer. Recently, Barnes and Mikkola have argued that, given this notion of substantivity, many of the central questions in the metaphysics of gender are nonsubstantive. Specifically, it is plausible that gender pluralism—the view that there are multiple, equally natural gender kinds—is true, but this view seems incompatible with the substantivity of gender. The goal of this paper is to argue that the notion of (...) substantivity can be understood in a way that accommodates gender pluralism. First, I claim that gender terms (at least as used in the ontology room) are referentially indeterminate, where referential indeterminacy holds in virtue of the way the world is. Second, I propose a degree-theoretic (or scalar) account of metaphysical substantivity; genders are substantial to the degree that they are determinate. I conclude that gender is relatively, although not absolutely, substantial. (shrink)

An increasing number of philosophers argue that indeterminacy is metaphysical (or worldly) in the sense that indeterminacy has its source in the world itself (rather than how the world is represented or known). The standard arguments for metaphysical indeterminacy are centered around the sorites paradox. In this essay, I present a novel argument for metaphysical indeterminacy. I argue that metaphysical indeterminacy follows from the existence of constitutive social construction; there is indeterminacy in the social world because there is indeterminacy in (...) how the social world is constructed. (shrink)

Indeterminacy is metaphysical (or worldly) if it has its source in the way the world is (rather than how it is represented or known). There are two questions we could ask about indeterminacy. First: does it exist? Second: is indeterminacy derivative? I focus on the second question. Specifically, I argue that (at least some) metaphysical indeterminacy can be derivative, where this roughly means that facts about indeterminacy are metaphysically grounded in facts about what is determinate.

Mereological nihilism is the view that no objects have proper parts. Despite how counter‐intuitive it is, it is taken quite seriously, largely because it solves a number of puzzles in the metaphysics of material objects – or so its proponents claim. In this article, I show that for every puzzle that mereological nihilism solves, there is a similar puzzle that (a) it doesn’t solve, and (b) every other solution to the original puzzle does solve. Since the solutions to the new (...) puzzles apply just as well to the old puzzles, the old puzzles provide no motivation to be a mereological nihilist. (shrink)

In “What you can’t expect when you’re expecting,” I argue that, if you don’t know what it’s like to be a parent, you cannot make this decision rationally—at least, not if your decision is based on what you think it would be like for you to become a parent. My argument hinges on the idea that becoming a parent is a transformative experience. This unique type of experience often transforms people in a deep and personal sense, and in the process, (...) changes their preferences. In section 1, I will explain transformative experience in terms of radical first-personal epistemic and self change. In section 2, I’ll explain the notion of subjective value that I use to develop the decision problem. In section 3, I will discuss the way we ordinarily combine our introspective assessments with testimony and evidence. In section 4, I will discuss the problems for rational decision-making. In section 5, I will explore the problem of first-personally transformed future selves. In section 6, I will engage with the main themes and arguments and ideas of the authors of the papers contributed to this volume. (shrink)

The Mass Density approach to GRW (GRWm for short) has been widely discussed in the quantum foundations literature. A crucial feature of GRWm is the introduction of a Criterion of Accessibility for mass, which allows to explain the determinacy of experimental outcomes thus also addressing the tails problem of GRW. However, the Criterion of Accessibility leaves the ontological meaning of the non-accessible portion of mass utterly unexplained. In this paper I discuss two viable approaches to non-accessible mass, which I call (...) anti-realist and realist, and will defend the latter. First, I show that the anti-realist approach suffers from various objections. Second, I develop an account of non-accessible mass density states as objectively indeterminate states of affairs. (shrink)

Barnes (2014) has argued in this journal for the following conditional: If there is any metaphysical indeterminacy, this must be at the most fundamental level of reality. To argue for this claim, Barnes relies on two principles that I shall call bivalent completeness and determinate link. According to the former, a complete description is a bivalent assignment of truth values to every sentence. The determinate link, instead, establishes that the determination relation between levels of reality preserves determinacy from one level (...) to another. In response to Barnes’ conclusion, Eva (2018) has recently pointed out that bivalent completeness is question begging. In this paper, I will first show why Eva's line of reasoning can be resisted. My aim will then be to present a stronger case against Barnes’ argument by challenging the determinate link. In the presence of metaphysical indeterminacy, the link between fundamental and derivative facts might itself be the locus of indeterminacy. I will conclude by showing that Barnes and Eva make many unwarranted assumptions regarding both indeterminacy and fundamentality. The logical space around the connection between these two notions appears to be much wider than what they seem to be aware of, or so I will argue. (shrink)

Many features of quantum mechanics (QM) suggest that, at the microscopic level, objects sometimes fail to determinately instantiate their properties. In recent years, many have argued that this phenomenon indicates the existence of an ontological kind of indeterminacy, often called metaphysical indeterminacy, which is supposed to affect the ontology of QM. As insisted by Glick ('Against Quantum Indeterminacy), however, once we look at the major realist approaches to QM we learn that the indeterminacy disappears from the description of the world (...) at its most fundamental level. This absence might be taken as a good reason for adopting some form of eliminativism towards quantum mechanical indeterminacy. The aim of this paper is to distinguish three ways of defending eliminativism, and to argue that none of them eventually succeeds. The upshot is that QM does in fact suggest the existence of metaphysical indeterminacy, although only as an emergent phenomenon. (shrink)

Metaphysical views typically draw some distinction between reality and appearance, endorsing realism about some subject matters and antirealism about others. There are different conceptions of how best to construe antirealist theories. A simple view has it that we are antirealists about a subject matter when we believe that this subject matter fails to obtain. This paper discusses an alternative view, which I will call the fundamentality-based conception of antirealism. We are antirealists in this sense when we think that the relevant (...) matter fails to be constitutive of fundamental reality. The following discussion will not rely on any particular understanding of fundamental reality, covering conceptions based on grounding, naturalness and truthmaking, to name three salient ones. This paper argues that there are serious issues with fundamentality-based metaphysics. It will be argued that: the fundamentality-based approach shapes and restricts our realist and antirealist views in unsatisfying ways, that it is unable to handle the conflicting facts that lie across the envisaged ‘layers’ of the metaphysically structured world, and that the methodological reasons for adopting the fundamentality-based approach fail. The paper will conclude with a diagnosis of the discussed issues, identifying a common source. (shrink)

In this paper, I examine a case for fundamental indeterminacy (FI) by Elizabeth Barnes and offer my counterarguments. Barnes' account of FI includes both the characterization of FI and why we need to accept it. I argue that her reasons for accepting FI can be challenged even when we accept her characterization of FI. Her main claim is that finding a fundamental proposition that our fundamental theory is indeterminate about (FPF) gives us a reason to accept FI in metaphysics. I (...) challenge her claim by pointing out more plausible options to address FPFs. An FPF may either indicate that the theory is nonfundamental or lead us to accept the antirealist view; there is no room for FI in either option. One may insist on accepting FI, but I argue that it is not theoretically rewarding enough. Hence, Barnes' case for FI can be contested. (shrink)

One challenge in providing an adequate definition of physical disability is unifying the heterogeneous bodily conditions that count as disabilities. We examine recent proposals by Elizabeth Barnes (2016), and Dana Howard and Sean Aas (2018), and show how this debate has reached an impasse. Barnes’ account struggles to deliver principled unification of the category of disability, whilst Howard and Aas’ account risks inappropriately sidelining the body. We argue that this impasse can be broken using a novel concept: marginalised functioning. Marginalised (...) functioning concerns the relationship between a person’s bodily capacities and their social world: specifically, their ability to function in line with the default norms about how people can typically physically function that influence the structuring of social space. We argue that attending to marginalised functioning allows us to develop, not one, but three different models of disability, all of which—whilst having different strengths and weaknesses—unify the category of disability without sidelining the body. (shrink)

Rampant non-factualism is the view that all non-fundamental matters are non-factual, in a sense inspired by Kit Fine (2001). The first half of this paper argues that if we take non-factualism seriously for any matters, such as morality, then we should take rampant non-factualism seriously. The second half of the paper argues that rampant non-factualism makes possible an attractive theory of vagueness. We can give non-factualist accounts of non-fundamental matters that nicely characterize the vagueness they manifest (if any). I suggest (...) that such non-factualist theories dissolve philosophical puzzlement about vagueness. In particular, the approach implies that philosophers should not try to say which of the sorites-paradox-forming claims are true; we should not try to solve the sorites paradox in that sense. (shrink)

Especially over the past twenty years, a number of analytic philosophers have embraced the idea that the world itself is vague or indeterminate in one or more respects. The issue then arises as to whether it can be the case that the world itself is indeterminate in all respects. Using as a basis Chinese Madhyamaka Buddhist thought, I offer two reasons for the coherence and intelligibility of the thesis that all concrete things are themselves indeterminate with respect to the ways (...) they are. The first reason draws on a notion reminiscent of the picture of reality as an amorphous lump, while the second reason makes use of the relativity of conceptual perspectives and determinations. Assuming that the world is the mere totality of all concrete things, I show that there is a genuine metaphysical possibility of the world’s being indeterminate in all respects. (shrink)

Grounding necessitarianism (GN) is the view that full grounds necessitate what they ground. Although GN has been rather popular among philosophers, it faces important counterexamples: For instance, A=[Socrates died] fully grounds C=[Xanthippe became a widow]. However, A fails to necessitate C: A could have obtained together with B=[Socrates and Xanthippe were never married], without C obtaining. In many cases, the debate essentially reduces to whether A indeed fully grounds C – as the contingentist claims – or if instead C is (...) fully grounded in A+, namely A plus some supplementary fact S (e.g. [Xanthippe was married to Socrates]) – as the necessitarian claims. Both sides typically agree that A+ necessitates C, while A does not; they disagree on whether A or A+ fully grounds C. This paper offers a novel defence of the claim that, in these typical cases, unlike A+, A fails to fully ground C – thereby bringing further support to GN. First and foremost, unlike A+, A fails to fully ground C because it fails to contain just what is relevant to do so, in two distinct senses – explanatory and generative relevance. Second, going for A, rather than A+, as a full ground undermines not just grounding necessitarianism, but modally weaker views which even contingentists may want to preserve. (shrink)

A world where there exists n concrete things is a count-determinate world. The orthodox view is count-determinacy is necessary; if to be is to be the value of a variable and the domain of quantification is enumerable, count-determinacy follows. Yet I argue how many there are can be indeterminate; count-indeterminacy is metaphysically possible and even likely actual. Notably, my argument includes rebuttals of Evans’ reductio of indeterminate identity and the Lewis/Sider ‘argument from vagueness’. Count-indeterminacy should therefore be recognized as another (...) basic form of genuine metaphysical indeterminacy, in addition to types recently defend by Barnes, Williams, and Wilson. (shrink)

We implement a recent characterization of metaphysical indeterminacy in the context of orthodox quantum theory, developing the syntax and semantics of two propositional logics equipped with determinacy and indeterminacy operators. These logics, which extend a novel semantics for standard quantum logic that accounts for Hilbert spaces with superselection sectors, preserve different desirable features of quantum logic and logics of indeterminacy. In addition to comparing the relative advantages of the two, we also explain how each logic answers Williamson’s challenge to any (...) substantive account of determinacy: For any proposition p, what could the difference between “p” and “it’s determinate that p” ever amount to? (shrink)

In recent years, a number of authors have defended the coherence and philosophical utility of the notion of metaphysical indeterminacy. Concurrently, the idea that reality can be stratified into more or less fundamental ‘levels’ has gained significant traction in the literature. Here, I examine the relationship between these two notions. Specifically, I consider the question of what metaphysical determinacy at one level of reality tells us about the possibility of metaphysical determinacy at other more or less fundamental levels. Towards this (...) end, I propose a novel conception of the way in which fundamental states of affairs determine derivative states of affairs in the presence of indeterminacy and construct a corresponding formal model of multilevel systems that demonstrates the compatibility of determinacy at the fundamental level with indeterminacy at higher levels, thereby rebutting Barnes' suggestion that indeterminacy at any level of reality implies indeterminacy at the fundamental level. (shrink)

I defend mereological nihilism, the view that there are no composite objects, against a challenge from ontological emergence, the view that some things have properties that are ‘something over and above’ the properties of their parts. As the nihilist does not believe in composite wholes, there is nothing in the nihilist's ontology to instantiate emergent properties – or so the challenge goes. However, I argue that some simples can collectively instantiate an emergent property, so the nihilist's ontology can in fact (...) accommodate emergent properties. Furthermore, I show that employing plural instantiation does not bloat the nihilist's ontology or ideology. (shrink)

Cases of grounding failure present a puzzle for fundamental metaphysics. Typically, solutions are thought to lie either in adding ontology such as haecceities or in re‐describing the cases by means of the ideology of metaphysical indeterminacy. The controversial status of haecceities has led some to favour metaphysical indeterminacy as the way to solve the puzzle. We consider two further treatments of grounding failure each of which, we argue, is a more plausible alternative. As such, the initial dichotomy is a false (...) one, and these alternative options deserve consideration before resorting to the heavyweight machinery of metaphysical indeterminacy. -/- . (shrink)

Miriam Schoenfield argues that moral realism and moral vagueness imply ontic vagueness. In particular, she argues that neither shifty nor rigid semantic accounts of vagueness can provide a satisfactory explanation of moral vagueness for moral realists. This paper constitutes a response. I argue that Schoenfield's argument against the shifty semantic account presupposes that moral indeterminacies can, in fact, be resolved determinately by crunching through linguistic data. I provide different reasons for rejecting this assumption. Furthermore, I argue that Schoenfield's rejection of (...) the rigid semantic account is based on a presupposition that ultimately implies the very same claim that is under dispute: the vagueness of moral predicates in imperfect languages persists in the perfect language, as well. (shrink)

Elizabeth Barnes and Robert Williams have developed a theory of metaphysical indeterminacy, via which they defend the theoretical legitimacy of vague objects. In this paper, we argue that while the Barnes–Williams theory supplies a viable account of genuine metaphysical vagueness, it cannot underwrite an account of genuinely vague objects. First we clarify the distinction between these two key theses. Then we argue that the Barnes–Williams theory of metaphysical vagueness not only fails to deliver genuinely vague objects, it in fact provides (...) grounds for rejecting them. (shrink)

This chapter presents several arguments related to Parfit's notion of evaluative imprecision and his imprecisionist lexical view of population ethics. After sketching Parfit's view, it argues that, contrary to Parfit, imprecision and lexicality are both compatible with thinking about goodness in terms of positions on a scale of value. Then, by examining the role that imprecision is meant to play in defusing spectrum argument, it suggests that imprecision should be identified with vagueness. Next, it argues that there is space for (...) robust moral realists to think of evaluative vagueness as a semantic phenomenon, illustrating this view with a version of conceptual role semantics on which the precisifications of betterness are correctness conditions for the precisifications of preference. Finally, it gives a probability-based argument against the imprecisionist lexical view. (shrink)