The identity of indiscernibles states that indiscernible objects must be identical. Many philosophers have held that the PII turns out to be either true but trivial, or non-trivial but false, depending on how the notion of discernibility is spelled out. In this paper, I propose and defend an account of this notion which aims to yield a minimally non-trivial and yet plausible version of the PII. I argue moreover that this version of the principle is immune to a number of (...) well-known and recent objections to the PII. (shrink)

A and B continue their conversation concerning the Identity of Indiscernibles. Both are aware of recent critiques of the principle that haven’t received replies; B summarizes those critiques, and A offers the replies that are due. B then raises a new worry.

Paul (Noûs 36:578–596, 2002; Noûs 40:623–659, 2006, The Handbook of Mereology, forthcoming) has argued for a bundle theory of objects that analyzes the bundling relation between properties and objects in terms of parthood relations. In this paper I argue that any mereological bundle theory with the explanatory power of Paul’s theory will entail the principle of the identity of indiscernibles (PII). This is problematic, since similar bundle theories seem to fall to Max Black’s two sphere counterexample to (PII). I argue, (...) however, that a fully developed mereological bundle theory provides a new way of interpreting Black’s two sphere universe that dispels the counterexample. I argue that this solution to Black’s puzzle is superior to other solutions on offer, and consequently that mereological bundle theory is an attractive ontological strategy for friends of (PII). (shrink)

What I call the argument from almost indiscernibles is an argument, put forward by Robert Adams in 1979, for the possibility of indiscernibles based on the possibility of almost indiscernibles. The argument is that if almost indiscernibles are possible, indiscernibles are possible, but since almost indiscernible are possible, indiscernibles are possible. The argument seems to be an improvement over the mere appeal to intuitions, like that suggested by Max Black, that situations in which there are indiscernibles are possible, for the (...) argument purports to give us a reason that indiscernibles are possible. In this paper I shall assess the argument by examining whether there is support for the conditional premise that if almost indiscernibles are possible, indiscernibles are possible. I shall argue that there are reasons to think that either the premise lacks support or almost indiscernibles are dispensable. If the premise lacks support, the argument does not establish the possibility of almost indiscernibles; if almost indiscernibles are dispensable, the argument is not needed to establish the possibility of indiscernibles. (shrink)

Universals have traditionally thought to obey the identity of indiscernibles, that is, it has traditionally been thought that there can be no perfectly similar universals. But at least in the conception of universals as immanent, there is nothing that rules out there being indiscernible universals. In this paper, I shall argue that there is useful work indiscernible universals can do, and so there might be reason to postulate indiscernible universals. In particular, I shall argue that postulating indiscernible universals can allow (...) a theory of universals to identify particulars with bundles of universals, and that postulating indiscernible universals can allow a theory of universals to develop an account of the resemblance of quantitative universals that avoids the objections that Armstrong’s account faces. Finally, I shall respond to some objections and I shall undermine the criterion of distinction between particulars and universals that says that the distinction between particulars and universals lies in that while there can be indiscernible particulars, there cannot be indiscernible universals. (shrink)

I begin by criticizing an elaboration of an argument in this journal due to Hawley , who argued that, where Leibniz’s Principle of the Identity of Indiscernibles faces counterexamples, invoking relations to save PII fails. I argue that insufficient attention has been paid to a particular distinction. I proceed by demonstrating that in most putative counterexamples to PII , the so-called Discerning Defence trumps the Summing Defence of PII. The general kind of objects that do the discerning in all cases (...) form a category that has received little if any attention in metaphysics. This category of objects lies between indiscernibles and individuals and is called relationals: objects that can be discerned by means of relations only and not by properties. Remarkably, relationals turn out to populate the universe. (shrink)

Saunders' recent arguments in favour of the weak discernibility of (certain) quantum particles seem to be grounded in the 'generalist' view that science only provides general descriptions of the worlIn this paper, I introduce the ‘generalist’ perspective and consider its possible justification and philosophical basis; and then look at the notion of weak discernibility. I expand on the criticisms formulated by Hawley (2006) and Dieks and Veerstegh (2008) and explain what I take to be the basic problem: that the properties (...) invoked by Saunders cannot be pointed to as ‘individuators’ of otherwise indiscernible (and thus numerically identical) entities because their ontological status remains underdetermined by the evidence and the established interpretation of the theory. In addition to to this, I suggest that Saunders does not deal adequately with bosons, and cannot do so exactly because he subscribes to PII and the generalist picture. The last part of the paper contains a critical examination of the claim (or at least implicit assumption) that the generalist picture should be regarded as obviously compelling by the modern-day empiricist. (shrink)

Abstract In this article, a critical assessment is carried out of the two available forms of nominalism with respect to the ontological constitution of material objects: resemblance nominalism and trope theory. It is argued that these two nominalistic ontologies naturally converge towards each other when the problems they have to face are identified and plausible solutions to these problems are sought. This suggests a synthesis between the two perspectives along lines first proposed by Sellars, whereby, at least at the level (...) of the simplest, truly fundamental constituents of reality, every particular is literally both an object and a particularized property (or, alternatively put, the distinction between objects and properties dissolves). Some potential problems and open issues for such an approach to nominalism in ontology are identified and discussed, with particular emphasis on the sort of fundamentalism that seems to crucially underlie the proposed ontology. Content Type Journal Article Pages 1-14 DOI 10.1007/s12136-011-0145-x Authors Matteo Morganti, Department of Philosophy, University of Rome ‘RomaTRE’, Via Ostiense, 234, 00144 Rome, Italy Journal Acta Analytica Online ISSN 1874-6349 Print ISSN 0353-5150. (shrink)

In a recent paper, Jiri Benovsky argues that the bundle theory and the substratum theory, traditionally regarded as ‘deadly enemies’ in the metaphysics literature, are in fact ‘twin brothers’. That is, they turn out to be ‘equivalent for all theoretical purposes’ upon analysis. The only exception, according to Benovsky, is a particular version of the bundle theory whose distinguishing features render unappealing. In the present reply article, I critically analyse these undoubtedly relevant claims, and reject them.

Possibilism—the view that there are non-actual, merely possible entities—is a surprisingly resilient doctrine.1 One particularly hardy strand of possibilism—the modal realism championed by David Lewis—continues to attract both foes who seek to demonstrate its falsity (or at least stare its advocates into apostasy) and friends who hope to defend modal realism (or, when necessary, modify modal realism so as to avoid problematic objections).2 Although I am neither a foe nor friend of modal realism (but some of my best friends are!), (...) like many I continue to be fascinated by the doctrine. (shrink)

Bundle Theory is the view that every concrete particular object is solely constituted by its universals. This theory is often criticized for not accommodating the possibility of symmetrical universes, such as one that contains two indiscernible spheres two meters from each other in otherwise empty space. One bundle theoretic solution to this criticism holds that the fact that the spheres stand in a weakly discerning—i.e., irreflexive and symmetric—relation, such as being two meters from, is sufficient for the numerical diversity of (...) the spheres. For this solution to be effective, however, it should be established that weak discernibility not only necessitates but also explains numerical diversity. In this paper, I argue that the fact that two objects have a certain distance between them does explain why they are non-identical. I also argue that the worry that the weak discernibility approach has some circularity problems is not well-founded. (shrink)

Bundle Theory is the view that every concrete particular object is solely constituted by its universals. This theory is often criticized for not accommodating the possibility of symmetrical universes, such as one that contains two indiscernible spheres two meters from each other in otherwise empty space. One bundle theoretic solution to this criticism holds that the fact that the spheres stand in a weakly discerning—i.e., irreflexive and symmetric—relation, such as being two meters from, is sufficient for the numerical diversity of (...) the spheres. For this solution to be effective, however, it should be established that weak discernibility not only necessitates but also explains numerical diversity. In this paper, I argue that the fact that two objects have a certain distance between them does explain why they are non-identical. I also argue that the worry that the weak discernibility approach has some circularity problems is not well-founded. (shrink)

I offer a mereological bundle of universals theory of material objects. The theory says that objects are identical to fusions of immanent universals at regions of space. Immanent universals are in the objects that instantiate them, and they can be wholly located at many regions of space. The version of the bundle theory I offer explains these characteristics of immanent universals, and it captures the instantiation relation in terms of the part-whole relation. The version of the theory I offer is (...) simpler and more unified than other mereological bundle theories. Yet, it is not as encompassing as other versions. For I suppose throughout that space is a particular substance, but not a bundle of properties. (shrink)

Is it possible to get by with just one ontological category? We evaluate L.A. Paul's attempt to do so: the mereological bundle theory. The upshot is that Paul's attempt to construct a one category ontology may be challenged with some of her own arguments. In the positive part of the paper we outline a two category ontology with property universals and kind universals. We will also examine Paul's arguments against a version of universal bundle theory that takes spatiotemporal co-location instead (...) of compresence or coinstantiation as the feature by which we can identify genuine bundles. We compare this novel theory, bundle theory with kinds, and Paul's mereological bundle theory and apply them to a case study concerning entangled fermions and co-located bosons. (shrink)

A modus tollens against zero-dimensional material objects is presented from the premises (i) that if there are zero-dimensional material objects then there are bare particulars, and (ii) that there are no bare particulars. The argument for the first premise proceeds by elimination. First, bare particular theory and bundle theory are motivated as the most appealing theories of property exemplification. It is then argued that the bundle theorist’s Ockhamism ought to lead her to reject spatiotemporally located zero-dimensional property instances. Finally, it (...) is argued that since she must accept such instances if she accepts zero-dimensional material object bundles, she ought to avoid the latter. This leaves bare particular theory as the default view of zero-dimensional material objects. The argument for the second premise invokes the thesis that the exemplification of at least one sparse property is a prerequisite for the existence of any particular. It is argued from Humean considerations that bare particulars fail this prerequisite. (shrink)

My aim in this article is to contribute to the larger project of assessing the relative merits of different theories of substance. An important preliminary step in this project is assessing the explanatory resources of one main theory of substance, the so-called bundle theory. This article works towards such an assessment. I identify and explain three distinct explanatory challenges an adequate bundle theory must meet. Each points to a putative explanatory gap, so I call them the Gap Challenges. I consider (...) three bundle-theoretic strategies for meeting these challenges. I argue that none of them goes very far. The upshot is that, absent other strategies for meeting the challenges, bundle theory involves a significant amount of stipulation. This black box makes bundle theory relatively weak with respect to its explanatory power—unless, of course, rival theories of substance are unable to do better. (shrink)

Cet article se propose de reprendre les discussions autour du principe d’identité des indiscernables (PIdI) en précisant le type d’entités qui pourraient y déroger. J’y défends l’idée que le rejet du PIdI ressortit à la possibilité de trois types de doubles : les répliques pures, ou reproductions parfaites, les doubles purs, doubles qui ne peuvent pas même être distingués par des relations spatio-temporelles, et enfin les coïncidents purs qui sont des doubles « superposés ». La thèse que je défends consiste (...) à montrer que l’existence de telles entités est non seulement concevable, mais même, pour les deux premières sortes, physiquement possible. Pour ce qui concerne la possibilité des coïncidents purs, le rejet de telles entités peut être appuyé indépendamment du PIdI sur un principe de parcimonie ontologique basé sur une indifférence causale. (shrink)

The bundle theory is a theory about the internal constitution of individuals. It asserts that individuals are entirely composed of universals. Typically, bundle theorists augment their theory with a constitutional approach to individuation entailing the thesis ‘identity of constituents is a sufficient ground for numerical identity’ (CIT). But then the bundle theory runs afoul of Black’s duplication case—a world containing two indiscernible spheres. Here I propose and defend a new version of the bundle theory that denies ‘CIT’, and which instead (...) conjoins it with a structural diversity thesis , according to which being separated by distance is a sufficient ground for numerical diversity. This version accommodates Black’s world as well as the three-spheres world —a world containing three indiscernible spheres, arranged as the vertices of an equilateral triangle. In this paper, I also criticize Rodriguez-Pereyra’s alternative attempt to defend the bundle theory against Black’s case and the case of the three-spheres world. (shrink)

We naturally think of the material world as being populated by a large number of individuals . These are things, such as my laptop and the particles that compose it, that we describe as being propertied and related in various ways when we describe the material world around us. In this paper I argue that, fundamentally speaking at least, there are no such things as material individuals. I then propose and defend an individual-less view of the material world I call (...) “generalism”. (shrink)

In 1952, two well-known characters called ‘A’ and ‘B’ met for the first time to argue about the Identity of Indiscernibles (Black, 1952). A argued that the principle is true, and B that it is false. By all accounts A took a bit of a beating and came out worst-off. Forty-three years later John O’Leary-Hawthorne offered a response on behalf of A that looked as if it would work so long as A was willing to accept the universal-bundle theory of (...) substance (Hawthorne, 1995). In 1997, A and B met again (Zimmerman, 1997). A took Hawthorne’s advice and revealed himself as a universal-bundle theorist. But B was well-prepared, and once more A took a beating. Since then Gonzalo Rodriguez-Pereyra (2004) has put the boot in, offering further criticism of A’s position. In recent years A has been rather quiet, leaving B to reign as the undisputed champion. However, it turns out that A is down, but not out. And now it’s time for A’s revenge. (shrink)

Realists about fictional characters posit a certain theoretical role and a candidate to fill this role. I will delineate the role realists take fictional characters like Emma Woodhouse to fill, and I will argue that it is better filled by what I will call ‘characterisations’. In explaining what I mean by ‘characterisations’, I will show that the existence of these entities is comparatively uncontroversial. Realists should acknowledge their existence, but doing so, I will argue, obviates the need to acknowledge the (...) existence of Emma and other fictional individuals. (shrink)

What is the relationship between objects and properties? According to a standard view, there are primitive individuals that ‘instantiate’ or ‘have’ various properties. According to a rival view, objects are mere ‘bundles’ of properties. While there are a number of reasons to be skeptical of primitive individuals, there are also a number of challenges that the bundle theorist faces. The goal of this paper is to formulate a view about the relationship between objects and properties that avoids many of the (...) problems inherent in both of these views. The view I will end up defending implies a particularly radical version of Monism, and it collapses the object-property distinction altogether. (shrink)

Broadly speaking, there are three views on whether Leibniz’s Principle of the Identity of Indiscernibles (PII) is violated in the case of similar particles. According to the earliest view, PII is always violated (call this the no discernibility view); according to the more recent weak discernibility view, PII is at least valid in a weak sense. No and weak discernibility have been referred to as orthodoxy. Steven French has argued that although PII is violated, similar particles can still be regarded (...) as individuals, or, alternatively, as non-individuals: French famously concluded therefore that metaphysics is underdetermined by physics. Call this thesis orthodox underdetermination. Most recently, some authors have turned against orthodoxy by arguing that PII is valid in more than a weak sense – call this the new discernibility view, also referred to as heterodoxy. Since heterodoxy is backed up by physical considerations, metaphysics now seems to be determined by physics: physics indicates that PII is valid. In this paper, I argue that with respect to entangled states, there are two ways to establish PII’s validity, which yield two different ontological interpretations of entanglement. Therefore, a form of underdetermination returns within the heterodox framework. I argue that heterodox underdetermination deserves some attention, because the two ontological interpretations might yield different explanations of the violation of Bell inequalities. (shrink)

One of the key questions in the contemporary analytic ontology concerns the relation between the Principle of Identity of Indiscernibles (PII) and the Bundle Theory (BT). The majority of authors believe that BT implies PII. Therefore, it is widely believed that the world violating PII presented by Max Black (1952. “The Identity of Indiscernibles.” Mind 61 (242): 153–64) is also devastating for BT. However, this has been questioned by Rodriguez-Pereyra (2004. “The Bundle Theory is Compatible with Distinct but Indiscernible Particulars.” (...) Analysis 64 (1): 72–81), who formulated an interpretation of BT with instances. Recently Robert (2019. “Can the Realist Bundle Theory Account for the Numerical Difference between Qualitavely Non-discernible Concrete Particulars?” Theorema 38 (1): 25–39) argued that this version of BT is not a constituent ontology and, therefore, Rodriguez-Pereyra’s solution comes at a price of excluding bundle theory from the domain of constituent ontologies, and, in this sense, it fails. I question Robert’s point by claiming that his account of constituent ontologies is too demanding. In particular, I show that the instance version of BT is compatible with the constrains defining constituent ontologies in general, and therefore Rodriguez-Pereyra’s argument is correct. (shrink)

ABSTRACTI present a new objection to Bundle Theory. The objection rests on the repeatability of universals, and targets every version of Bundle Theory that assumes that concrete particulars constituted by the same universals are numerically identical. The only way that bundle theorists can elude this objection is to admit the possibility of distinct bundles constituted by the same universals. If even this view is untenable, then Bundle Theory as such is hopeless. Finally, I show how the present inquiry reshapes the (...) dialectical relationship between Bundle Theory and the principle of Identity of Indiscernibles. (shrink)

Objects partially resemble when they are alike in some way but not entirely alike. Partial resemblance, then, involves similarity in a respect. It has been observed that talk of “respects” appears to be thinly‐veiled talk of properties. So some theorists take similarity in a respect to require property realism. I will go a step further and argue that similarity in intrinsic respects (partial intrinsic resemblance) requires properties to be immanent in objects. For a property to be immanent in an object (...) is roughly for it to be wholly present in that object. (So understood, immanence does not imply repeatability, and thus tropes count as immanent.) If two objects are intrinsically similar in one way but not another, there must be a difference between the two ways. And if the similarity is between the objects as they are in themselves, then this difference, too, must be within the objects. Partial intrinsic resemblance thus requires internal structure. Without it, there can be no distinctions between ways in which things are intrinsically alike and ways in which they aren't. I will argue, further, that distinctions between properties that transcend objects fail to account for the possibility of partial intrinsic resemblance. (shrink)

In this paper we deal with the problem of identity and individuality in quantum mechanics. We analyze three definitions of the concept of an individual and propose to check their merits in relation to the theory. In order to achieve our goals our approach also ties those definitions of individuality to two distinct kinds of naturalism in ontology: a strong version, according to which quantum mechanics must somehow authorize in a positive fashion the ontological concepts being dealt with, and a (...) weak naturalism, according to which quantum mechanics must be only compatible with those ontological concepts. We conclude that strong naturalism is incompatible with the three concepts of individuality in quantum mechanics, and we argue that weak naturalism is not completely motivated, so that the best position to be assumed, in the end, is that the entities are simply not individuals. That is, in its craving to be compatible with strong naturalism, individuality ends up evaporating and we are left with non-individuals. (shrink)

The Weak Principle of the Identity of Indiscernibles (weak PII), states that numerically distinct items must be discernible by a symmetrical and irreflexive relation. Recently, some authors have proposed that weak PII holds in non relativistic quantum mechanics, contradicting a long tradition claiming PII to be simply false in that theory. The question that arises then is: are relations allowed in the scope of PII? In this paper, we propose that quantum mechanics does not help us in deciding matters concerning (...) that problem, since that is a metaphysical problem rather than a quantum mechanical one. We argue further that weak PII is unmotivated on metaphysical grounds. We examine three metaphysical theses (bundle theory, counting, empiricism) that may provide reasons for one to sustain PII, and we conclude that weak PII gets no independent motivation from them. (shrink)

The Received View on quantum non-individuality is, roughly speaking, the view according to which quantum objects are not individuals. It seems clear that the RV finds its standard expression nowadays through the use of the formal apparatuses of non-reflexive logics, mainly quasi-set theory. In such logics, the relation of identity is restricted, so that it does not apply for terms denoting quantum particles; this “lack of identity” formally characterizes their non-individuality. We face then a dilemma: on the one hand, identity (...) seems too important to be given up, on the other hand the RV seems to require that identity be given up. In this paper we shall discuss how the specific characterization of the RV through non-reflexive logics came to be framed. We examine some of the main objections to this version of the RV and argue that they are misguided under this specific “non-reflexive” understanding of the RV. Finally, we shall also argue that this non-reflexive view is not the only option for a metaphysical articulation of the RV: less radical approaches to identity and logic are open. In particular, some of these alternative approaches to the RV we present may be immune to most of the criticisms presented against the non-reflexive approach. (shrink)

Recently, there has been a debate as to whether or not the principle of the identity of indiscernibles (the PII) is compatible with quantum physics. It is also sometimes argued that the answer to this question has implications for the debate over the tenability of ontic structural realism (OSR). The central aim of this paper is to establish what relationship there is (if any) between the PII and OSR. It is argued that one common interpretation of OSR is undermined if (...) the PII turns out to be false, since it is committed to a version of the bundle theory of objects, which implies the PII. However, if OSR is understood as the physical analogue of (sophisticated) mathematical structuralism then OSR does not imply the PII. It is further noted that it is (arguably) a virtue of OSR that it is compatible with a version of the PII for possible worlds. (shrink)

The subject matter of this thesis is analytic ontology. Chapters II and III deal with two versions of trope theory, or moderate nominalism; these are defined as ontologies which recognise properties and relations but no (real) universals. The key notion of both theories, trope, is characterised as an abstract particular. What the abstractness amounts to differs between the two. Yet another difference is that simplicity is an essential trait of a trope according to one theory, but not according to the (...) other. Though exact similarity is said to play an important role in both theories, as it turns out, this does not seem to be the case. The ontology dealt with in chapter IV is a mixture of moderate nominalism concerning qualities and realism concerning relations. In it, quality instances (moments) and universal relations are the ultimate constituents of the universe. While relations and moments are considered to be constituents of states of affairs, which are characterised as objects of higher orders, complexes that are objects of the first order are made up of moments on their own. Among these complexes one finds the ordinary objects. Paradoxically, although relations are necessary for the existence of complex first order objects, relations are not thought to be among the contents of these objects. The main subject of chapter V is a particular version of moderate realism; it is an ontology which is realistic in its recognition of universals and moderate in its recognition of instances of these universals. Instances combine to form complex networks. A theoretically motivated claim is that although each instance has a predicational aspect as well as a universal one, it is simple in the sense of lacking internal predicative structure; though, this claim can be called into question. Keywords: analytic ontology, moderate nominalism, moderate realism, particular, universal, abstract, concrete, abstract particular, abstract universal, concrete particular, concrete universal, trope, moment, complex unity, collection, instance, unit attribute, intensional aspect, predicational aspect, continuous composite, articulated composite. (shrink)

Space and time are two obvious candidates as dimensions of reality. Yet, are they the only two dimensions of reality? Famously, David Lewis maintained the doctrine of ―modal realism‖, the thesis that possible worlds exist and are entities as concrete as the actual world that we live in. In this paper, I will explore the idea that modality can be construed as a dimension along with space and time. However, although Lewis‘ modal realism is the main source of inspiration for (...) this construal of modality, I will argue that something else is required for having a modal dimension. (shrink)

Bundle theory reduces particulars to bundles of properties. Bundle theorists have been working to explain individuation within an ontology of repeatable properties, but the outcomes are not satisfactory. Even the trope approach toward properties is not capable of establishing individuation. This article argues that bundle theorists are wrong in searching for individuators within the bundles of properties. Rather, indi­viduation should be established within ontologically more fundamental level of events. Events, with their spatial and temporal character, enable us to individuate the (...) bundles of properties involved and this is one of the reasons for the superiority of bundle theory to other competitive theories of substance. (shrink)

In a recent paper, Sun Demirli (2010) proposes an allegedly new way of conceiving of individuation in the context of the bundle theory of object constitution. He suggests that allowing for distance relations to individuate objects solves the problems with worlds containing indiscernible objects that would otherwise affect the theory. The aim of the present paper is i) To show that Demirli’s proposal falls short of achieving this goal and ii) To carry out a more general critical assessment of the (...) issue by appraising the costs and benefits of Demirli’s view as well as of existing alternatives. (shrink)