Metaphysical Indeterminacy

Possibility semantics offers an elegant framework for a semantic analysis of modal logic that does not recruit fully determinate entities such as possible worlds. The present papers considers the application of possibility semantics to the modeling of the indeterminacy of the future. Interesting theoretical problems arise in connection to the addition of object-language determinacy operator. We argue that adding a two-dimensional layer to possibility semantics can help solve these problems. The resulting system assigns to the two-dimensional determinacy operator a well-known (...) logic (coinciding with the logic of universal modalities under global consequence). The paper concludes with some preliminary inroads into the question of how to distinguish two-dimensional possibility semantics from the more established branching framework. (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 feature of language is that we are able to make mistakes in our use of language. Amongst other sorts of mistakes, we can misspeak, misspell, missign, or misunderstand. Given this, it seems that our metaphysics of words should be flexible enough to accommodate such mistakes. It has been argued that a nominalist account of words cannot accommodate the phenomenon of misspelling. I sketch a nominalist trope-bundle view of words that can.

Jay Newhard (2021) proposes a novel solution to the Liar Paradox, which he calls the alethic indeterminacy solution to the Liar Paradox. Bradley Armour-Garb (2021) raises a pair of objections to the alethic indeterminacy solution. Both objections are based upon the alethic indeterminacy solution’s alleged commitment that the truth conditions for a Liar Sentence are indeterminate, and therefore not true. In this paper, this alleged commitment is shown to be mistaken. The alethic indeterminacy solution is compatible with maintaining that the (...) truth conditions for a Liar Sentence are a non-truth-functional biconditional which is true, and not indeterminate. Logically complex sentences are typically and standardly treated as truth-functional, and the philosophical literature on non-truth-functionality is diffuse. Two independent accounts of non-truth-functional biconditionals are defended. The first account is based on the claim that indicative conditionals express a non-truth-functional dependency relation between consequent and antecedent. The second account is based upon connected sentences having interdependent truth conditions, which can occur with any polyadic connective. These accounts are fully general, not ad hoc measures. Each account solves both of Armour-Garb’s objections. With both objections met, the alethic indeterminacy solution is shown to be a viable solution to the Liar Paradox worth further development. (shrink)

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. (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.

These are my materials (a short precis, and replies to Alan Rhoda and Daniel Rubio) for an invited symposium on my book _The Open Future: Why Future Contingents are All False_ (OUP, 2021) in IJPR. [The commentaries from Rhoda/Rubio are available on their respective PhilPapers profiles.].

This paper discusses a puzzle raised by Sharon Berry, published in Analysis. The question in the background of this puzzle is how we should deal with seemingly plausible possibility judgements that commit us to counterfactual truths that find no basis in reality. Three answers to this question and their corresponding solutions to the puzzle will be discussed. The last answer provides a way to make sense of the claim that it is in some cases indeterminate whether a proposition is possible (...) and offers an account of indeterminate modal status. (shrink)

A standard approach to indeterminacy treats ‘determinately’ and ‘indeterminately’ as modal operators. Determinacy behaves like necessity; indeterminacy like contingency. This raises two questions. What is the appropriate modal system for these operators? And how should we interpret that system? Ken Akiba has developed an account of ontic indeterminacy that interprets possible worlds as worldly precisifications. He argues that this account vindicates S4 as the logic of indeterminacy. In this paper I explore one significant and surprising consequence of this view. I (...) do this in two stages. First, I prove a technical result, which I call the Infinite Indeterminacy Theorem. Roughly put, this theorem states that, at any given precisification w, either every instance of indeterminacy admits of never-ending higher-order indeterminacy, or else there's indeterminacy in an infinite amount of distinct atomic formulas. In slogan form: either all indeterminacy is infinitely ascending or else there's infinitely wide indeterminacy. Second, I unpack the metaphysical consequences of this technical result (under its intended interpretation) and assess their plausibility. I conclude that these consequences commit Akiba's theory to highly contentious – and arguably untenable – views about the metaphysics of indeterminacy and related matters. (shrink)

Orthodox quantum theory tells us that properties of quantum systems are represented by self-adjoint operators, and that two properties are incompatible just in case their respective operators do not commute. We present a puzzle for this orthodoxy, pinpointing the exact assumptions at play. Our solution to the puzzle specifically challenges the assumption that non-commuting operators represent incompatible properties. Instead, they represent incompatible levels of specification of determinates for a single determinable. This solution yields insight into the nature of so-called quantum (...) indeterminacy and demonstrates a new and fruitful application of the determinable-determinate relation in quantum theory. (shrink)

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)

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)

A non-solipsist form of presentness is usually thought to require the non-relative co-presentness of space-like separated events, where this requirement further implies the non-relative simultaneity of these events. Since special relativity is thought to rule out any global, non-relative simultaneity, typical non-solipsist forms of presentness are taken to be inconsistent with special relativity. To address this problem, we re-explain the relationship between the non-solipsism of presentness and co-presentness by appealing to metaphysical indeterminacy. We propose presentness indeterminacy, the thesis that where (...) an event, p, is determinately present, any event in space-like relation to p lacks a determinate tense. We argue that for many theories of time, indeterminate co-presentness is all that the non-solipsism of presentness requires. Since there is no determinate co-presentness, the inconsistency between presentness and special relativity in these theories disappears. (shrink)

The “consequence argument”, together with the “luck objection”, which are summed up by the “standard argument against free will”, state that if our volition were dependent on physical causally indeterministic processes, our actions would lack control and, thereby, result in random behavior that would be a mere matter of luck and chance. In particular, quantum indeterminacy is supposed to be of no use in support of libertarian agent-causation theories because any volitional act interfering with the probability distributions de fining quantum (...) laws would lead to its violation. Building upon recent conjectural work questioning this assumption (Clarke 2010, Kastner 2016, Masi 2023), it is shown, with a concrete example involving quantum indeterminacy, how a hypothetical agent with access to the temporal ordering of events can pre-determine the result of a process taking place in time without modifying the probability laws defining it. This conclusion is then taken as a basis for a libertarian panpsychist interpretative model. (shrink)

ABSTRACT:Organismal superposition holds that the same individual both is and is not an organism, as a consequence of organismal pluralism. When coupled with the assumption that death is the cessation of an organism, this entails that there is no unique answer as to whether brain death is biological death. This essay argues that concerns about organismal pluralism and superposition do not undermine a theory of biological death, nor entail any metaphysical indeterminacy about the biological vital status of a brain-dead individual.

Recent philosophical discussions about metaphysical indeterminacy have been substantiated with the idea that quantum mechanics, one of the most successful physical theories in the history of science, provides explicit instances of worldly indefiniteness. Against this background, several philosophers underline that there are alternative formulations of quantum theory in which such indeterminacy has no room and plays no role. A typical example is Bohmian mechanics in virtue of its clear particle ontology. Contrary to these latter claims, this paper aims at showing (...) that different pilot-wave theories do in fact instantiate diverse forms of metaphysical indeterminacy. Namely, I argue that there are various questions about worldly states of affairs that cannot be determined by looking exclusively at their ontologies and dynamical laws. Moreover, it will be claimed that Bohmian mechanics generates a new form of modal indeterminacy. Finally, it will be concluded that ontological clarity and indeterminacy are not mutually exclusive, i.e., the two can coexist in the same theory. (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)

In his work on the open future, Patrick Todd outlines three models of how to deal with future contingents. These models must answer two questions: one metaphysical, about what facts there are in the world; one semantic, about how to deal with sentences involving ‘will.’ Model 1 has a privileged timeline. Model 2 has an actual future timeline but leaves it indeterminate which timeline that is. Model 3 has no future timeline. All three give will-sentences a modal treatement, as a (...) box over available futures. I will argue that Todd’s second model has problems and should be improved. The first is that it denies what Todd labels as the basic metaphysical intuition behind open-futurism. The second is that indeterminacy about the facts that characterize the actual timeline breaks through into indeterminate identity. I propose a fix to model 2 eliminating its actual future and resolving an issue that arises in applying the neutral semantics Todd endorses to indeterminate sentences. This improved model, I suggest, may even compare favorably to Todd’s preferred model 3. (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)

There are many things, ideas, and entities that we encounter every single day that can be described as vague, that is, one cannot precisely classify them as members of a specific class of objects. Although many hold the opinion that vagueness is either a deficiency of spoken languages or something that exists merely because we do not have all relevant details, a third group of people assume that vagueness is something real. This simply means that objects, including living beings, are (...) vague. But if vagueness is a real thing, why do people ignore it when trying to explain a natural phenomenon, a syndrome, etc.? The reason is that people have a deep respect for pure, abstract objects with exact properties. But this has a negative effect on our understanding of our cosmos. Therefore, we investigate how vagueness really affects exact sciences and how the incorporation of vagueness will improve our understanding of our world. (shrink)

This paper argues that “free will” is vague. The argument has two steps. First, I argue that free will is a matter of degrees and, second, that there are no sharp boundaries separating free decisions and actions and non‐free ones. After presenting the argument, I focus on one significant consequence of the thesis, although others are mentioned along the way. In short, considerations of vagueness help understand the logic behind so‐called manipulation arguments, but also show why these arguments are ultimately (...) flawed. (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)

Our first goal here is to show how one can use a modal language to explicate potentiality and incomplete or indeterminate domains in mathematics, along the lines of previous work. We then show how potentiality bears on some longstanding items of concern to Mark Steiner: the applicability of mathematics, explanation, and de re propositional attitudes toward mathematical objects.

My aim in this paper is to provide some introductory coordinates aiming at orienting a unified discourse on the doctrine of vagueness in Peirce. After tracing some of the stages in Peircean scholarship that have brought the concept of vagueness into focus, I will show that vagueness, as it appears in Peircean philosophy, is a three-dimensional concept. Thus, while vagueness is a concept that appears in a logical-semiotic dimension – and more specifically as a problem related to the quantification of (...) the subject within the propositional context – it is also articulated in an epistemological and metaphysical dimension. Here I focus primarily on the semiotic dimension and suggest how an account of vagueness might hold together the epistemological and metaphysical consequences of the notion of vagueness. (shrink)

Suppose that fictional objects are abstract objects dependent for their existence and their identity on the creative intentions of their authors. Is an author who intends to create indeterminately identical fictional objects committed to incoherent created objects? My claim is that she is not so committed. I argue that indeterminate identity is an ambiguous notion, allowing for an incoherent interpretation and for at least three coherent ones; and I show that if an author of fiction applies coherent indeterminate identity when (...) creating fictional objects, she succeeds in creating coherent objects, whereas she fails to create fictional objects when she tries to apply incoherent indeterminate identity in her creation. In so doing, I offer a reply to a challenge first raised by Everett against realist philosophers on fictional objects and more recently reproposed by Friedell, allowing for the creation of fictional objects along the lines proposed by Evnine. (shrink)

This article defends the existence of _borderline consciousness._ In borderline consciousness, conscious experience is neither determinately present nor determinately absent, but rather somewhere between. The argument in brief is this. In considering what types of systems are conscious, we face a quadrilemma. Either nothing is conscious, or everything is conscious, or there’s a sharp boundary across the apparent continuum between conscious systems and nonconscious ones, or consciousness is a vague property admitting indeterminate cases. Assuming mainstream naturalism about consciousness, we ought (...) to reject the first three options, which forces us to the fourth, indeterminacy. Standard objections to the existence of borderline consciousness turn on the inconceivability of borderline cases. However, borderline cases are only inconceivable by an inappropriately demanding standard of conceivability. I conclude with some plausible cases and applications. (shrink)

This paper asks: Is the quantifier variantist committed to metaphysical vagueness? My investigation of this question goes via a study of vague existence. I’ll argue that the quantifier variantist is committed to vague existence and that the vague existence posited by the variantist requires a puzzling sort of metaphysical vagueness. Specifically, I distinguish between (what I call) positive and negative metaphysical vagueness. Positive metaphysical vagueness is (roughly) the claim that there is vagueness in the world; negative metaphysical vagueness is (roughly) (...) the claim that there is vagueness that is not in our language or thought. I’ll argue that the quantifier variantist’s commitment to vague existence comes with positive metaphysical vagueness -- even if it doesn't require negative metaphysical vagueness. (shrink)

The way we represent the world in thought and language is shot through with indeterminacy: we speak of red apples and yellow apples without thereby committing to any sharp cutoff between the application of the predicate ‘red’ and of the predicate ‘yellow’. But can reality itself be indeterminate? In other words, can indeterminacy originate in the mind-independent world, and not only in our representations? If so, can the phenomenon also arise at the microscopic scale of fundamental physics? Section 1 of (...) this Element provides a brief overview of the question of indeterminacy. Section 2 discusses the thesis that the world is comprised of indeterminate objects, whereas Section 3 focuses on the thesis that there are indeterminate states of affairs. Finally, Section 4 is devoted to the case study of indeterminacy in quantum physics. (shrink)

This edited collection provides new perspectives on some metaphysical questions arising in quantum mechanics. These questions have been long-standing and are of continued interest to researchers and graduate students working in physics, philosophy of physics and metaphysics. It features contributions from a diverse set of researchers, ranging from senior scholars to junior academics, working in varied fields, from physics to philosophy of physics and metaphysics. The contributors reflect on issues about fundamentality (is quantum theory fundamental? If so, what is its (...) fundamental ontology?), ontological dependence (how do ordinary objects exist even if they are not fundamental?), realism (what kind of realism is compatible with quantum theory?), indeterminacy (can the world itself exhibit ontological indeterminacy?). With contributions from both physicists (including Nobel Prize winner Gerard 't Hooft), science communicators and philosophers. (shrink)

This paper summarises the contributions to our Topical Collection on indeterminacy and underdetermination. The collection includes papers in ethics, metaethics, logic, metaphysics, epistemology, philosophy of science, philosophy of language and philosophy of computation.

From Aristotle’s puzzle about the indeterminacy of future contingents to Duhem and Quine’s observations about the underdetermination of theory by evidence, the concepts of indeterminacy and underdetermination have been a recurrent theme in philosophy. As well as a continued interest in classic problems, recent years have seen new applications of these notions in various research contexts. This Topical Collection showcases recent work on indeterminacy and underdetermination from diverse branches of philosophy, including philosophy of language, logic, philosophy of mathematics, metaphysics, ethics, (...) metaethics, epistemology, philosophy of science, and philosophy of computation. The collection aims to highlight the similarities and differences between the many manifestations of these phenomena so that insights and conceptual tools developed in each philosophical sub-discipline can stimulate research in the others. (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)

If there are fundamental laws of nature, can they fail to be exact? In this paper, I consider the possibility that some fundamental laws are vague. I call this phenomenon 'fundamental nomic vagueness.' I characterize fundamental nomic vagueness as the existence of borderline lawful worlds and the presence of several other accompanying features. Under certain assumptions, such vagueness prevents the fundamental physical theory from being completely expressible in the mathematical language. Moreover, I suggest that such vagueness can be regarded as (...) 'vagueness in the world.' For a case study, we turn to the Past Hypothesis, a postulate that (partially) explains the direction of time in our world. We have reasons to take it seriously as a candidate fundamental law of nature. Yet it is vague: it admits borderline (nomologically) possible worlds. An exact version would lead to an untraceable arbitrariness absent in any other fundamental laws. However, the dilemma between fundamental nomic vagueness and untraceable arbitrariness is dissolved in a new quantum theory of time's arrow. (shrink)

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. (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.

The definitions of yu 宇 and zhou 宙 in the “Gengsang Chu 庚桑楚” chapter of the Zhuangzi have been cited as the earliest definitions of space and time in the Chinese philosophical tradition. However, careful analysis of chosen modern translations reveals that the definitions entail rather obscure relationships between the Dao and space and time. I argue that the obscurity is not inherent in the text, but arises from the practice of rendering yu and zhou as the conceptual counterparts of (...) space and time or related concepts. Instead, I propose that we leave the terms untranslated. This practice would not only forestall interpretive difficulties concerning the Dao’s relations to space and time, but it would also preserve the Zhuangzist yu and zhou as two distinctive, ontic notions that indicate the Dao’s indeterminate modes of existence, a unique feature of the Zhuangzi. (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)

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. (shrink)

The Causal Exclusion Problem is raised in many domains, including in the metaphysics of macroscopic objects. If there is a complete explanation of macroscopic effects in terms of the microscopic entities that compose macroscopic objects, then the efficacy of the macroscopic will be threatened with exclusion. I argue that we can avoid the problem if we accept that macroscopic objects are ontically vague. Then, it is indeterminate which collection of microscopic entities compose them, and so information about microscopic entities is (...) insufficient to provide a complete explanation of certain properties of macroscopic objects. After outlining this solution, I consider several objections. (shrink)

This chapter argues that quantum indeterminacy can be construed as a merely derivative phenomenon. The possibility of merely derivative quantum indeterminacy undermines both a recent argument against quantum indeterminacy due to David Glick, and an argument against the possibility of merely derivative indeterminacy due to Elizabeth Barnes.

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)

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 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. (shrink)

The paper attempts to interpret P. van Inwagen’s refutation of Evans’ argument that there cannot be vague objects and defend it against the charge of inconsistency raised by Radim Bělohrad. However, such an interpretation is not without a cost. Therefore another interpretation of van Inwagen’s example of the Cabinet is offered which evades Evans’ charge of inconsistency against indeterminate identity as it does not need the notion at all.

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.

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)