It has been argued that non-relativistic quantum mechanics is the best hunting ground for genuine examples of metaphysical indeterminacy. Approaches to metaphysical indeterminacy can be divided into two families: meta-level and object-level accounts. It has been shown :27–245, 2010. https://doi.org/10.1080/00048400903097786; Skow in Philosophical Quarterly 60:851–858, 2010) that the most popular version of the meta-level accounts, namely the metaphysical supervaluationism proposed by Barnes and Williams, fails to deal with quantum indeterminacy. Such a fact has been taken by many as a challenge (...) to adapt supervaluationism to quantum cases. In this paper, I will focus on the very last of these attempts, i.e. the situation semantics account proposed by Darby and Pickup. After having shown where quantum indeterminacy arises and having surveyed the assumptions endorsed by the participants of the debate, I turn to Darby and Pickup’s proposal. I argue that, despite the machinery introduced, their account still fails to account for quantum indeterminacy. After considering some possible counterarguments, I suggest in the conclusion that one can plausibly extend the argument to those meta-level approaches that treat quantum indeterminacy as worldly indecision. (shrink)

This paper explores quantum indeterminacy, as it is operative in the failure of value‐definiteness for quantum observables. It first addresses questions about its existence, its nature, and its relations to extant quantum interpretations. Then, it provides a critical discussions of the main accounts of quantum indeterminacy.

In Calosi and Wilson (Phil Studies 2019/2018), we argue that on many interpretations of quantum mechanics (QM), there is quantum mechanical indeterminacy (QMI), and that a determinable-based account of metaphysical indeterminacy (MI), as per Wilson 2013 and 2016, properly accommodates the full range of cases of QMI. Here we argue that this approach is superior to other treatments of QMI on offer, both realistic and deflationary, in providing the basis for an intelligible explanation of the interference patterns in the double-slit (...) experiment. We start with a brief overview of the motivations for QMI and for a determinable-based account of MI (§1). We then apply a developed 'glutty' implementation of determinable-based QMI to the superposition-based QMI present in the double-slit experiment, and positively compare the associated explanation of double-slit interference with that available on a metaphysical supervaluationist account of QMI (§2). We then present and respond to objections, due to Glick (2017) and Torza (2017), either to QMI (§3) or to our specific account of QMI (§4); in these sections we also positively compare our treatment of double-slit interference to that available on Glick's deflationary treatment of QMI. We conclude with some dialectical observations (§5). (shrink)

On many currently live interpretations, quantum mechanics violates the classical supposition of value definiteness, according to which the properties of a given particle or system have precise values at all times. Here we consider whether either metaphysical supervaluationist or determinable-based approaches to metaphysical indeterminacy can accommodate quantum metaphysical indeterminacy (QMI). We start by discussing the standard theoretical indicator of QMI, and distinguishing three seemingly different sources of QMI (S1). We then show that previous arguments for the conclusion that metaphysical supervaluationism (...) cannot accommodate QMI, due to Darby 2010 and Skow 2010, are unsuccessful, in leaving open several supervaluationist responses. We go on to provide more comprehensive argumentation for the negative conclusion. Here, among other results, we establish that the problems for supervaluationism extend far beyond the concern that is the focus of Darby's and Skow's discussions (according to which a supervaluationist approach is incompatible with the orthodox interpretation, in light of the Kochen-Specker theorem) to also attach to common understandings of other interpretations on which there is QMI (S2). We then argue that a determinable-based account can successfully accommodate all three varieties of QMI (S3). We close by observing the positive mutual bearing of our results on the coherence and intelligibility of both quantum mechanics and metaphysical indeterminacy (S4). (shrink)

It has frequently been suggested that quantum mechanics may provide a genuine case of ontic vagueness or metaphysical indeterminacy. However, discussions of quantum theory in the vagueness literature are often cursory and, as I shall argue, have in some respects been misguided. Hitherto much of the debate over ontic vagueness and quantum theory has centered on the “indeterminate identity” construal of ontic vagueness, and whether the quantum phenomenon of entanglement produces particles whose identity is indeterminate. I argue that this way (...) of framing the debate is mistaken. A more thorough examination of quantum theory and the phenomenon of entanglement reveals that quantum mechanics is best interpreted as supporting what I call the “vague property” construal of ontic vagueness, where vague properties are understood in terms of determinable properties without the corresponding determinates. (shrink)

Ethical vagueness has garnered little attention. This is rather surprising since many philosophers have remarked that the science of ethics lacks the precision that other fields of inquiry have. Of the few philosophers who have discussed ethical vagueness the majority have focused on the implications of vagueness for moral realism. Because the relevance of ethical vagueness for other metaethical positions has been underexplored, my aim in this paper is to investigate the ramifications of ethical vagueness for expressivism. Ultimately, I shall (...) argue that expressivism does not have the resources to adequately account for ethical vagueness, while cognitivism does. This demonstrates an advantage that cognitivism holds over expressivism. (shrink)

The question of how properties are individuated is extremely important. Consider the following proposals. To be in pain is to be in a certain neurological state. To be red is to appear red to normal observers in standard conditions. To be obligatory is to maximize the good. Each makes a claim of property identity. Each is a substantive metaphysical thesis of wide interest. None can be studied with due scrutiny in the absence of a general account of property identity. Here, (...) I will survey existing accounts and suggest a new account in terms of grounding that has some advantages over the other candidates. (shrink)

Far from being unwelcome or impossible in a mathematical setting, indeterminacy in various forms can be seen as playing an important role in driving mathematical research forward by providing “sources of newness” in the sense of Hutter and Farías :434–449, 2017). I argue here that mathematical coincidences, phenomena recently under discussion in the philosophy of mathematics, are usefully seen as inducers of indeterminacy and as put to work in guiding mathematical research. I suggest that to call a pair of mathematical (...) facts a coincidence is roughly to suggest that the investigation of connections between these facts isn’t worthwhile. To say of this pair, “That’s no coincidence!” is to suggest just the opposite. I further argue that this perspective on mathematical coincidence, which pays special attention to what mathematical coincidences do, may provide us with a better view of what mathematical coincidences are than extant accounts. I close by reflecting on how understanding mathematical coincidences as generating indeterminacy accords with a conception of mathematical research as ultimately aiming to reduce indeterminacy and complexity to triviality as proposed in Rota Indiscrete thoughts, Birkhäuser, 1997). (shrink)

Theorists who advocate worldly (metaphysical or ontological) indeterminacy—the idea that the world itself is indeterminate in one or more respects—should address how we understand the signifying nature and function of language in light of worldly indeterminacy. I first attend to Sengzhao and Jizang, two leading thinkers in Chinese Sanlun Buddhism, to reconstruct a Chinese Madhyamaka notion of ontic indeterminacy. Then, I draw on the thinkers’ views to propose a provisional (non-definitive) understanding of the nature and use of language. Under this (...) understanding, an expression signifying a thing is provisional in that the expression connotes no determinate feature of the thing. (shrink)

If the world itself is metaphysically indeterminate in a specified respect, what follows? In this paper, we develop a theory of metaphysical indeterminacy answering this question.

A naïve perspective on the world suggests that the world we live in is full of vague objects. In this chapter, a version of the supervaluationist framework will be proposed to provide a systematic conception of such a naïve perspective. Precisifications of a vague object will be characterized as objects that, were they actual objects, every determinate truth about the vague object would be true about them. It will be argued that this view is more effective than other versions of (...) supervaluationism at accommodating commonsensical and metaphysical considerations. The view leaves room for vague identity as a kind of “no fact of the matter.” Thus, Evans’ argument against ontic vagueness fails in a natural way. (shrink)

Might it be that world itself, independently of what we know about it or how we represent it, is metaphysically indeterminate? This article tackles in turn a series of questions: In what sorts of cases might we posit metaphysical indeterminacy? What is it for a given case of indefiniteness to be 'metaphysical'? How does the phenomenon relate to 'ontic vagueness', the existence of 'vague objects', 'de re indeterminacy' and the like? How might the logic work? Are there reasons for postulating (...) this distinctive sort of indefiniteness? Conversely, are there reasons for denying that there is indefiniteness of this sort? (shrink)

ABSTRACT Many phenomena appear to be indeterminate, including material macro-object boundaries and certain open future claims. Here I provide an account of indeterminacy in metaphysical, rather than semantic or epistemic, terms. Previous accounts of metaphysical indeterminacy have typically taken this to involve its being indeterminate which of various determinate states of affairs obtain. On my alternative account, MI involves its being determinate that an indeterminate state of affairs obtains. I more specifically suggest that MI involves an object's having a determinable (...) property, but not having any unique determinate of that determinable. I motivate the needed extension of the traditional understanding of determinables, then argue that a determinable-based account of MI accommodates, in illuminating fashion, both ‘glutty’ and ‘gappy’ cases of MI, while satisfactorily treating concerns about MI stemming from Evans’ argument and the problem of the many. (shrink)

This paper presents a new theory of vagueness, which is designed to retain the virtues of the fuzzy theory, while avoiding the problem of higher-order vagueness. The theory presented here accommodates the idea that for any statement S₁ to the effect that 'Bob is bald' is x true, for x in [0, 1], there should be a further statement S₂ which tells us how true S₁ is, and so on - that is, it accommodates higher-order vagueness without resorting to the (...) claim that the metalanguage in which the semantics of vagueness is presented is itself vague, and without requiring us to abandon the idea that the logic - as opposed to the semantics - of vague discourse is classical. I model the extension of a vague predicate P as a blurry set, this being a function which assigns a degree of membership or degree function to each object o, where a degree function in turn assigns an element of [0, 1] to each finite sequence of elements of [0, 1]. The idea is that the assignment to the sequence (0.3, 0.2), for example, represents the degree to which it is true to say that it is 0.2 true that o is P to degree 0.3. The philosophical merits of my theory are discussed in detail, and the theory is compared with other extensions and generalisations of fuzzy logic in the literature. (shrink)

This paper presents and defends a definition of vagueness, compares it favourably with alternative definitions, and draws out some consequences of accepting this definition for the project of offering a substantive theory of vagueness. The definition is roughly this: a predicate 'F' is vague just in case for any objects a and b, if a and b are very close in respects relevant to the possession of F, then 'Fa' and 'Fb' are very close in respect of truth. The definition (...) is extended to cover vagueness of many-place predicates, of properties and relations, and of objects. Some of the most important advantages of the definition are that it captures the intuitions which motivate the thought that vague predicates are tolerant, without leading to contradiction, and that it yields a clear understanding of the relationships between higher-order vagueness, sorites susceptibility, blurred boundaries, and borderline cases. The most notable consequence of the definition is that the correct theory of vagueness must countenance degrees of truth. (shrink)

Can we solve the Problem of the Many, and give a general account of the indeterminacy in definite descriptions that give rise to it, by appealing to metaphysically indeterminate entities? I argue that we cannot. I identify a feature common to the relevant class of definite descriptions, and derive a contradiction from the claim that each such description is satisfied by a metaphysically indeterminate entity.

The problem of the many poses the task of explaining mereological indeterminacy of ordinary objects in a way that sustains our familiar practice of counting these objects. The aim of this essay is to develop a solution to the problem of the many that is based on an account of mereological indeterminacy as having its source in how ordinary objects are, independently of how we represent them. At the center of the account stands a quasi-hylomorphic ontology of ordinary objects as (...) material objects with multiple individual forms. (shrink)

Sometimes, when comparing a pair of items, it appears that neither is better than the other, nor that they are equally good, relative to a certain value that they bear. Cases of this kind have come to be referred to as superhard comparisons. What grounds superhard comparisons? On the dominant views, held by Joseph Raz and Ruth Chang, they are grounded, at least partially, in the failure of the three classic value relations—‘better than’, ‘worse than’, and ‘equally good’. On an (...) alternative view, which might be called the vagueness view, first developed by John Broome, they are grounded in vagueness about which of the classic value relations holds between the items. In this paper, I pay special attention to superhard comparisons in the context of choice and develop a novel argument against the dominant views on the basis of an account of decision-making under vagueness in ‘better than’. The upshot is that a new vagueness view emerges. (shrink)

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.

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)

The article introduces a special issue of the journal _Metaphysica_ on vagueness and ontology. The conventional view has it that all vagueness is semantic or representational. Russell, Dummett, Evans and Lewis, inter alia, have argued that the notion of “ontic” or “metaphysical” vagueness is not even intelligible. In recent years, a growing minority of philosophers have tried to make sense of the notion and have spelled it out in various ways. The article gives an overview and relates the idea of (...) ontic vagueness to the unquestioned phenomenon of fuzzy spatiotemporal boundaries and to the associated “problem of the many”. It briefly discusses the question of whether ontic vagueness can be spelled out in terms of “vague identity”, emphasizes the often neglected role of the difference between sortal and non-sortal ontologies and suggests a deflationary answer to the ill-conceived question of whether the “ultimate source” of vagueness lies either in language or in the world. (shrink)

A common feature of all standard theories of the laws of nature is that they are "absolutist": They take laws to be either all metaphysically necessary or all contingent. Science, however, gives us reason to think that there are laws of both kinds, suggesting that standard theories should make way for "non-absolutist" alternatives: theories which accommodate laws of both modal statuses. In this paper, we set out three explanatory challenges for any candidate non-absolutist theory and discuss the prospects of the (...) two extant candidates in light of these challenges. We then develop our own non-absolutist theory, the essentialist DTA account, which combines the nomic-necessitation or DTA account with an essentialist approach to metaphysical modality in order to meet the three explanatory challenges. Finally, we argue that the distinction between kinematical and dynamical laws found in physical theories supports both non-absolutism in general and our proposed essentialist DTA view in particular. (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)

This is the revised version of an invited keynote lecture delivered at the "1st Australian Computing and Philosophy Conference". The paper is divided into two parts. The first part defends an informational approach to structural realism. It does so in three steps. First, it is shown that, within the debate about structural realism, epistemic and ontic structural realism are reconcilable. It follows that a version of OSR is defensible from a structuralist-friendly position. Second, it is argued that a version of (...) OSR is also plausible, because not all relata are logically prior to relations. Third, it is shown that a version of OSR is also applicable to both sub-observable and observable entities, by developing its ontology of structural objects in terms of informational objects. The outcome is informational structural realism, a version of OSR supporting the ontological commitment to a view of the world as the totality of informational objects dynamically interacting with each other. The paper has been discussed by several colleagues and, in the second half, ten objections that have been moved to the proposal are answered in order to clarify it further. (shrink)

Can quantum theory provide examples of metaphysical indeterminacy, indeterminacy that obtains in the world itself, independently of how one represents the world in language or thought? We provide a positive answer assuming just one constraint of orthodox quantum theory: the eigenstate-eigenvalue link. Our account adds a modal condition to preclude spurious indeterminacy in the presence of superselection sectors. No other extant account of metaphysical indeterminacy in quantum theory meets these demands.

The topic of this paper is whether there is metaphysical vagueness. It is shown that it is important to distinguish between the general phenomenon of indeterminacy and the more narrow phenomenon of vagueness (the phenomenon that paradigmatically rears its head in sorites reasoning). Relatedly, it is important to distinguish between metaphysical indeterminacy and metaphysical vagueness. One can wish to allow metaphysical indeterminacy but rule out metaphysical vagueness. As is discussed in the paper, central argument against metaphysical vagueness, like those of (...) Gareth Evans and Mark Sainsbury, would if successful rule out metaphysical indeterminacy. One way to argue specifically against the possibility of metaphysical vagueness might be thought to be to argue for a specific theory of the nature of vagueness according to which vagueness is a semantic phenomenon. But it is shown that there are complications also pertaining to arguments with that structure. Toward the end of the paper, I discuss Trenton Merricks’ well-known argument against a semantic view on vagueness and for a metaphysical view. (shrink)

Philosophy Compass 2: 896-909. (Link to Philosophy Compass.).

I will here present a number of problems concerning the idea that there is ontological vagueness, and the related claim that appeal to this idea can help solve some vagueness-related problems. A theme underlying the discussion will be the distinction between vagueness specifically and indeterminacy more generally (and, relatedly, the distinction between ontological vagueness and ontological indeterminacy). Even if the world is somehow ontologically indeterminate it by no means follows that it is, properly speaking, ontologically vague.1..

This unique anthology of new, contributed essays offers a range of perspectives on various aspects of ontic vagueness. It seeks to answer core questions pertaining to onticism, the view that vagueness exists in the world itself. The questions to be addressed include whether vague objects must have vague identity, and whether ontic vagueness has a distinctive logic, one that is not shared by semantic or epistemic vagueness. The essays in this volume explain the motivations behind onticism, such as the plausibility (...) of mereological vagueness and indeterminacy in quantum mechanics and they offer various arguments both for and against ontic vagueness; onticism is also compared with other, competing theories of vagueness such as semanticism, the view that vagueness exists only in our linguistic representation of the world. Gareth Evans’s influential paper of 1978, “Can There Be Vague Objects?” gave a simple but cogent argument against the coherence of ontic vagueness. Onticism was subsequently dismissed by many. However, in recent years, researchers have become aware of the logical gaps in Evans’s argument and this has triggered a new wave of interest in onticism. Onticism is now widely regarded as at least a coherent view. Reflecting this growing consensus, the present anthology for the first time puts together essays that are focused on onticism and its various facets and it fills in the lacuna in the literature on vagueness, a much-discussed subject in contemporary philosophy. (shrink)

In this paper I explore the implications of moral vagueness (viz., the vagueness of moral predicates) for non-naturalist metaethical theories like those recently championed by Shafer-Landau, Parfit, and others. I characterise non-naturalism in terms of its commitment to 7 theses: Cognitivism, Correspondence, Atomism, Objectivism, Supervenience, Non-reductivism, and Rationalism. I start by offering a number of reasons for thinking that moral predicates are vague in the same way in which ‘red’, ‘tall’, and ‘heap’ are said to be. I then argue that (...) the moral non-naturalist seeking to countenance moral vagueness faces a dilemma: are moral properties vague, or perfectly sharp? On either horn of the dilemma, serious problems arise for some of the central tenets of non-naturalism: vague properties seem to threaten Objectivism, Supervenience, and Non-reductivism; on the other hand, sharp properties raise problems for Supervenience and Rationalism. The difficulties on each horn of the dilemma are real, and while they may not be insuperable, they do, at the very least, drastically limit the things non-naturalists can consistently say about moral properties, facts, and reasons. (shrink)