Relativized Metaphysical Modality (RMM: Murray and Wilson, 'Relativized metaphysical modality', Oxford Studies in Metaphysics, 2012; Murray, Perspectives on Modal Metaphysics, 2017) exploits 'two-dimensionalist' resources to metaphysical, rather than epistemological, ends: the second dimension offers perspective-dependence without contingency, diverting attacks on 'Classical' analyses of modals (in effect, analyses validating S5 and the Barcan Formulae). Here, we extend the RMM program in two directions. First, we harvest resources for RMM from Lewis's 1980 'Context--Index' (CI) framework: (a) the ban in CI on binding (...) into context-arguments (akin to Kaplan's 'monstrosity' ban) projects a bright line between perspective-dependence and contingency; and (b) CI-postulated connections among meaning, content, truth, argument-structure, context, and modality collectively generate a 'Generalized Humphrey Problem' for any non-Classical analysis (examples covered include appeals to accessibility, contingent domains, and counterpart relations). Second, we sharpen the tools of RMM-based metaphysical analysis, and extend their domain of coverage across familiar anomalies for Classical modals: we revisit earlier RMM-based bulwarks for S5 (against 'Chisholm's Paradox' for moderate flexibility of essence, and nomological necessitarianism); and we now similarly shore up the Barcan Formulae (against the apparent contingency of existence and nonexistence). (shrink)

Existentialism is compatible with a broadly biological vision of who we are. This thesis is grounded in an analysis of “concrete” or “individual” possibility, which differs from standard conceptions of possibility in that it allows for possibilities to come into being or disappear through time. Concrete possibilities are introduced both in individual life and by major transitions in evolution. In particular, the advent of ultrasociality and of language has enabled human goals to be formulated in partial independence from the vestigial (...) “goal” of biological replication. The existentialist stance is validated by the necessity of choice grounded in emotion, in a way that does not require a commitment to a Kantian Will. (shrink)

This book provides a detailed exposition of one of the most practical and popular methods of proving theorems in logic, called Natural Deduction. It is presented both historically and systematically. Also some combinations with other known proof methods are explored. The initial part of the book deals with Classical Logic, whereas the rest is concerned with systems for several forms of Modal Logics, one of the most important branches of modern logic, which has wide applicability.

Esta enciclopédia abrange, de uma forma introdutória mas desejavelmente rigorosa, uma diversidade de conceitos, temas, problemas, argumentos e teorias localizados numa área relativamente recente de estudos, os quais tem sido habitual qualificar como «estudos lógico-filosóficos». De uma forma apropriadamente genérica, e apesar de o território teórico abrangido ser extenso e de contornos por vezes difusos, podemos dizer que na área se investiga um conjunto de questões fundamentais acerca da natureza da linguagem, da mente, da cognição e do raciocínio humanos, bem (...) como questões acerca das conexões destes com a realidade não mental e extralinguística. A razão daquela qualificação é a seguinte: por um lado, a investigação em questão é qualificada como filosófica em virtude do elevado grau de generalidade e abstracção das questões examinadas (entre outras coisas); por outro, a investigação é qualificada como lógica em virtude de ser uma investigação logicamente disciplinada, no sentido de nela se fazer um uso intenso de conceitos, técnicas e métodos provenientes da disciplina de lógica. O agregado de tópicos que constitui a área de estudos lógico-filosóficos é já visível, pelo menos em parte, no Tractatus Logico-Philosophicus de Ludwig Wittgenstein, uma obra publicada em 1921. E uma boa maneira de ter uma ideia sinóptica do território disciplinar abrangido por esta enciclopédia, ou pelo menos de uma porção substancial dele, é extrair do Tractatus uma lista dos tópicos mais salientes aí discutidos; a lista incluirá certamente tópicos do seguinte género, muitos dos quais se podem encontrar ao longo desta enciclopédia: factos e estados de coisas; objectos; representação; crenças e estados mentais; pensamentos; a proposição; nomes próprios; valores de verdade e bivalência; quantificação; funções de verdade; verdade lógica; identidade; tautologia; o raciocínio matemático; a natureza da inferência; o cepticismo e o solipsismo; a indução; as constantes lógicas; a negação; a forma lógica; as leis da ciência; o número. (shrink)

This book develops a novel generalization of possible world semantics, called ‘world line semantics’, which recognizes worlds and links between world-bound objects (world lines) as mutually independent aspects of modal semantics. Addressing a wide range of questions vital for contemporary debates in logic and philosophy of language and offering new tools for theoretical linguistics and knowledge representation, the book proposes a radically new paradigm in modal semantics. This framework is motivated philosophically, viewing a structure of world lines as a precondition (...) of modal talk. The author provides a uniform analysis of quantification over individuals (physical objects) and objects of thought (intentional objects). The semantic account of what it means to speak of intentional objects throws new light on accounts of intentionality and singular thought in the philosophy of mind and offers novel insights into the semantics of intensional transitive verbs. (shrink)

Chisholm's Paradox and the Four Worlds Paradox are paradoxes about the cross-world identity of artifacts that are made of parts. The paradoxes are described as derivable in S5 modal logic from principles concerning the essentiality of the original matter of an artifact and the Tolerance Principle concerning possible changes in the original matter. On one hand, the original matter is essential to the artifact; on the other hand, bare identity or distinctness with respect to the original matter can be inferred (...) by applying the Tolerance Principle in S5. ;This dissertation analyzes two solutions that have been proposed. Nathan Salmon developed an Intransitive Accessibility Solution that rejects S5 as the logic for metaphysical modality. We show that Salmon's argument for the intransitivity of metaphysical possibility is unsound. The fundamental problem in Salmon's account is his attempt to derive the mode of metaphysical possibility from the accessibility relation between the possible worlds, which, by the theory of possible worlds that Salmon advocates, has to be determined by metaphysical possibilities with a pre-determined mode. The conclusion of Salmon's argument only reiterates a premise of the argument. We also discuss Salmon's other defenses, and show that these defenses are unsuccessful. ;Graeme Forbes proposes a Counterpart Solution. His solution replaces the standard two-valued semantics by a counterpart semantics with infinitely many degrees of truth-value. Our view is that Forbes' solution is unsatisfactory. Forbes avoids the identity problem by formulating the problem in terms of similarity relation. We argue that the similarity relation must not be a semantic device for representing identity. ;Our analysis reveals two versions of tolerance principle that have not been distinguished in literature. The paradoxes are associated with the Strong Tolerance Principle. We argue that the Strong Tolerance Principle is false. The intuition of tolerance is sufficiently described by the Weak Tolerance Principle. Moreover, we argue that the knowing of the possibilities about the origination of an artifact is empirical. The knowledge of the historical background and the origination of the artifact is needed for knowing the possibilities. With this view, S5 as the logic of metaphysical modality can be defended. (shrink)

First - order modal logic is very much under current development, with many different semantics proposed. The use of rigid objects goes back to Saul Kripke. More recently, several semantics based on counterparts have been examined, in a development that goes back to David Lewis. There is yet another line of research, using intensional objects, that traces back to Richard Montague. I have been involved with this line of development for some time. In the present paper, I briefly sketch several (...) of the approaches to first - order modal logic. Then I present one that I call FOIL in the Montague tradition that, I believe, is both expressive and natural. I briefly discuss in what sense it can be made to encompass the other approaches. Finally, I provide tableau rules to go with the FOIL semantics. (shrink)

What is it for something to be essential to an item? For some time, it was standard to think that the concept of necessity alone can provide an answer: for something to be essential to an item is for it to be strictly implied by the existence of that item. We now tend to think that this view fails because its analysans is insufficient for its analysandum. In response, some argue that we can supplement the analysis in terms of necessity (...) with a further condition. In this paper I argue that this view is untenable in its current form. I then provide a glimmer of hope to those who think that essence is at least partially analyzable in terms of necessity. (shrink)

The idea of fragmentalism has been proposed by Kit Fine as a non-standard view of tense realism. This paper examines a modal version of the view, called modal fragmentalism, which combines genuine realism and realism of modality. Modal fragmentalism has been recently discussed by Iaquinto. But unlike Iaquinto, who primarily focused on possibilities de re, in this paper, we focus on expressions of possibilities de dicto. We argue that the chief idea of modal realism should be that different worlds are (...) distinguished not just in terms of how things are differently with respect to each world, but also in terms of how things could have been differently with respect to each world. This demands a realism-oriented semantics for suppositional contents, and more specifically, for conditionals. By deploying a multidimensional semantics for conditionals, we show that there are good reasons to consider modal fragmentalism as a serious approach in metaphysics, which shares many similarities with the fragmentalism of tense. (shrink)

Three different notions of concepts are outlined: one derives from Leibniz, while the other two derive from Frege. The Leibnizian notion is the subject of his "calculus of concepts" (which is really an algebra). One notion of concept from Frege is what we would call a "property", so that when Frege says "x falls under the concept F", we would say "x instantiates F" or "x exemplifies F". The other notion of concept from Frege is that of the notion of (...) sense, which played various roles within Frege's theory. This notion of concept can be generalized and, as such, accounts for our intuitive talk of "x's concept of ...", where the ellipsis can be filled in with a name for individual, a property, or a relation, etc. After outlining these three notions, I then discuss how (axiomatic) object theory offers a distinct, precise regimentation of each of the three notions. (shrink)

In this book, Zalta attempts to lay the axiomatic foundations of metaphysics by developing and applying a (formal) theory of abstract objects. The cornerstones include a principle which presents precise conditions under which there are abstract objects and a principle which says when apparently distinct such objects are in fact identical. The principles are constructed out of a basic set of primitive notions, which are identified at the end of the Introduction, just before the theorizing begins. The main reason for (...) producing a theory which defines a logical space of abstract objects is that it may have a great deal of explanatory power. It is hoped that the data explained by means of the theory will be of interest to pure and applied metaphysicians, logicians and linguists, and pure and applied epistemologists. (shrink)

Monism is a metaphysical view according to which there is only one fundamental object. This paper will explore monism within the context of truthmaker theory, or Truthmaker Monism, a view rarely discussed in literature. Although few truthmaker theorists defend monism, at least explicitly, some theories seem to share the spirit of monism to some extent. Interestingly, they are proposed as solutions for the same problem, called the problem of negative truth. A close examination will show that while each of these (...) solutions can account for the problem, they are unsatisfactory for different reasons. This paper will suggest a novel solution to the problem of negative truth which preserves the advantages of existing solutions while avoiding the difficulties with which they are faced. (shrink)

Natural language provides motivation for studying modal backwards-looking operators such as “now”, “then” and “actually” that evaluate their argument formula at some previously considered point instead of the current one. This paper investigates the expressive power over models of both propositional and first-order basic modal language enriched with such operators. Having defined an appropriate notion of bisimulation for first-order modal logic, I show that backwards-looking operators increase its expressive power quite mildly, contrary to beliefs widespread among philosophers of language and (...) formal semanticists. That in turn presents a strong argument for the use of operator-based systems in the semantics of natural language, instead of systems with explicit quantification over worlds and times that have become a de-facto standard for such applications. The popularity of such explicit-quantification systems is shown to be based on the misinterpretation of a claim by Cresswell, which led many philosophers and linguists to assume that introducing “now” and “then” is expressively equivalent to explicitly quantifying over worlds and times. (shrink)

This paper aims to construct a logic of alternative-I that provides a proper conceptual framework for talk of possible-I in decision-making context, and thereby solves what we call the paradox of possible-I. The model of our logic, Alt-I model, is an adaptation of N. Belnap’s branching-time model, and the STIT (see to it that) operator defined on the model serves to represent choices and decisions made by actual and counterfactual agents. We conclude this paper by discussing the application of Alt-I (...) model to the case of digital twins, digital copies of a person. (shrink)

Self-consciousness in non-human animals is a complex phenomenon which raises both conceptual and methodological problems. First, what do we mean by the concept of ‘self-consciousness’? Secondly, what is the best experimental approach to self-consciousness? This paper gives a short overview of the concept of self-consciousness in section 1. We can understand the concept of self-consciousness as capturing the ability of subjects to consciously think about themselves as themselves. If this is accurate, then it is prudent to look at a broad (...) bundle of abilities which are related to this ability. The paper then focuses on advantages and problems of the multipronged approach, a kind of empirical approach which uses several different test criteria to determine whether a subject is self-conscious or not. Section 2 briefly contrasts this kind of approach with other possibilities. The main disparity is to singlepronged approaches, which have been discussed and dismissed in greater detail elsewhere. Section 3 discusses the advantages of a multipronged approach, whereas section 4 is dedicated to the discussion of some of its problems. (shrink)

Gideon Rosen’s [1990 Modal fictionalism. Mind, 99, 327–354] Modal Fictionalist aims to secure the benefits of realism about possible-worlds, whilst avoiding commitment to the existence of any world other than our own. Rosen [1993 A problem for fictionalism about possible worlds. Analysis, 53, 71–81] and Stuart Brock [1993 Modal fictionalism: A response to Rosen. Mind, 102, 147–150] both argue that fictionalism is self-defeating since the fictionalist is tacitly committed to the existence of a plurality of worlds. In this paper, I (...) develop a new strategy for the fictionalist to pursue in response to the Brock–Rosen objection. I begin by arguing that modal fictionalism is best understood as a paraphrase strategy that concerns the propositions that are expressed, in a given context, by modal sentences. I go on to argue that what is interesting about paraphrastic fictionalism is that it allows the fictionalist to accept that the sentence ‘there is a plurality of worlds’ is true without thereby committing her to the existence of a plurality of worlds. I then argue that the paraphrastic fictionalist can appeal to a form of semantic contextualism in order to communicate her status as an anti-realist. Finally, I generalise my conception of fictionalism and argue that Daniel Nolan and John O’Leary-Hawthorne [1996 Reflexive fictionalisms. Analysis, 56, 26–32] are wrong to suggest that the Brock-Rosen objection reveals a structural flaw with all species of fictionalism. (shrink)

In recent work, Jonathan Schaffer (Mind 119: 341–376, 2010) has attempted to argue that counterpart theorists are committed to holding that any two actual objects are bound together in a modally substantial sense. By clarifying the core elements of counterpart theory, I explain why Schaffer’s argument fails.

Possible worlds represent you as being certain ways, as having a different lives, different hopes, and different friends. A foundational question in the philosophy of modality thus emerges: in virtue of what does a world represent you in these ways? In this paper, we focus on David Lewis's answer to this metarepresentational question: Counterpart Theory.

Two kinds of explanation might be put forward. The first goes like this: the necessary connection between the location of a whole and the location of its parts holds because the location of the whole is nothing but the collective location of its parts. The second style of explanation goes like this: the connection holds because what it is for a material whole to have something as a part, is (perhaps among other things) for the whole to contain the part.

We care not just how things are but how they could have been otherwise – about possibility and necessity as well as actuality. Many philosophers regard such talk as beyond the reach of respectable science, since observation tells us how things are but not how they could have been otherwise. I argue that, on the contrary, such criticisms are ill-founded: possibility and necessity are studied in natural science, for example through phase spaces, abstract mathematical representations of the possible states of (...) a physical system. The possibility is objective, not merely epistemic, though it may be more restricted than pure metaphysical possibility. The elements of a phase space are very similar to Kripke's possible worlds, despite being time slices rather than total histories. The absence of explicit modal operators in the mathematical models used by scientists does not show science to be non-modal; rather, it manifests reliance on a mathematical framework for theorizing about objective possibility similar to the mathematical framework of possible worlds model theory. (shrink)

This paper explains and defends the idea that metaphysical necessity is the strongest kind of objective necessity. Plausible closure conditions on the family of objective modalities are shown to entail that the logic of metaphysical necessity is S5. Evidence is provided that some objective modalities are studied in the natural sciences. In particular, the modal assumptions implicit in physical applications of dynamical systems theory are made explicit by using such systems to define models of a modal temporal logic. Those assumptions (...) arguably include some necessitist principles. -/- Too often, philosophers have discussed ‘metaphysical’ modality — possibility, contingency, necessity — in isolation. Yet metaphysical modality is just a special case of a broad range of modalities, which we may call ‘objective’ by contrast with epistemic and doxastic modalities, and indeed deontic and teleological ones (compare the distinction between objective probabilities and epistemic or subjective probabilities). Thus metaphysical possibility, physical possibility and immediate practical possibility are all types of objective possibility. We should study the metaphysics and epistemology of metaphysical modality as part of a broader study of the metaphysics and epistemology of the objective modalities, on pain of radical misunderstanding. Since objective modalities are in general open to, and receive, natural scientific investigation, we should not treat the metaphysics and epistemology of metaphysical modality in isolation from the metaphysics and epistemology of the natural sciences. -/- In what follows, Section 1 gives a preliminary sketch of metaphysical modality and its place in the general category of objective modality. Section 2 reviews some familiar forms of scepticism about metaphysical modality in that light. Later sections explore a few of the many ways in which natural science deals with questions of objective modality, including questions of quantified modal logic. (shrink)

Simon Saunders and David Wallace have proposed an attractive semantics for interpreting linguistic communities embedded in an Everettian multiverse. It provides a charitable interpretation of our ordinary talk about the future, and allows us to retain a principle of bivalence for propositions and to retain the law of excluded middle in the logic of propositions about the future. But difficulties arise when it comes to providing an appropriate account of the metaphysics of macroscopic objects and events. I evaluate various metaphysical (...) frameworks which might be combined with the Saunders–Wallace semantics. I conclude that the most appropriate metaphysics to underwrite the semantics renders Everettian quantum mechanics a theory of non-overlapping worlds. (shrink)

Section 1 introduces the category of objective modality, closely related to linguists’ category of circumstantial or dynamic modals, and explains metaphysical modality as its maximal element. Section 2 discusses various kinds of skepticism about modality, as in Hume and recent authors, and argues that it is illmotivated to apply such skepticism to metaphysical modality but not to more restricted objective modalities, including nomic modality. Section 3 suggests that the role of counterfactual conditionals in applications of scientific theories involves an objective (...) modal dimension. Section 4 briefly discusses the role of objective probabilities in scientific theories as exemplifying the scientific study of objective modality. Section 5 summarizes a case study of dynamical systems theory, widely used in natural science, as a mathematical theory whose intended applications are objectively modal, as perspicuously articulated in a language with modal and temporal operators and propositional quantification. State spaces in natural science characterize objective possibilities. Section 6 argues that, although those possibilities are usually more restricted than metaphysical possibility, their scientific study is a partial study of metaphysical possibility too. (shrink)

Quine (1960, Word and object. Cambridge, Mass.:MIT Press, ch. 2) claims that there are a variety of equally good schemes for translating or interpreting ordinary talk. ‘Rabbit’ might be taken to divide its reference over rabbits, over temporal slices of rabbits, or undetached parts of rabbits, without significantly affecting which sentences get classified as true and which as false. This is the basis of his famous ‘argument from below’ to the conclusion that there can be no fact of the matter (...) as to how reference is to be divided. Putative counterexamples to Quine’s claim have been put forward in the past (see especially Evans 1975; 1975, Journal of Philosophy, LXXII(13), 343–362. Reprinted in McDowell (Ed.), Gareth Evans: Collected papers. Oxford: Clarendon Press.), and various patches have been suggested (e.g. Wright (1997, The indeterminacy of translation. In C. Wright & B. Hale (Eds.), A companion to the philosophy of language (pp. 397–426). Oxford: Blackwell)). One lacuna in this literature is that one does not find any detailed presentation of what exactly these interpretations are supposed to be. Drawing on contemporary literature on persistence, the present paper sets out detailed semantic treatments for fragments of English, whereby predicates such as ‘rabbit’ divide their reference over four-dimensional continuants (Quine’s rabbits), instantaneous temporal slices of those continuants (Quine’s rabbit-slices) and the simple elements which compose those slices (undetached rabbit parts) respectively. Once we have the systematic interpretations on the table, we can get to work evaluating them. (shrink)

This paper formulates a general epistemological argument against what I call non-causal realism, generalizing domain specific arguments by Benacerraf, Field, and others. First I lay out the background to the argument, making a number of distinctions that are sometimes missed in discussions of epistemological arguments against realism. Then I define the target of the argument—non-causal realism—and argue that any non-causal realist theory, no matter the subject matter, cannot be given a reasonable epistemology and so should be rejected. Finally I discuss (...) and respond to several possible responses to the argument. In addition to clearing up and avoiding numerous misunderstandings of arguments of this kind that are quite common in the literature, this paper aims to present and endorse a rigorous and fully general epistemological argument against realism. (shrink)

Conventionalism about mathematics claims that mathematical truths are true by linguistic convention. This is often spelled out by appealing to facts concerning rules of inference and formal systems, but this leads to a problem: since the incompleteness theorems we’ve known that syntactic notions can be expressed using arithmetical sentences. There is serious prima facie tension here: how can mathematics be a matter of convention and syntax a matter of fact given the arithmetization of syntax? This challenge has been pressed in (...) the literature by Hilary Putnam and Peter Koellner. In this paper I sketch a conventionalist theory of mathematics, show that this conventionalist theory can meet the challenge just raised , and clarify the type of mathematical pluralism endorsed by the conventionalist by introducing the notion of a semantic counterpart. The paper’s aim is an improved understanding of conventionalism, pluralism, and the relationship between them. (shrink)

Standard lore has it that a proper name is a temporally rigid designator. It picks out the same entity at every time at which it picks out an entity at all. If the entity in question is an enduring continuant then we know what this means, though we are also stuck with a host of metaphysical puzzles concerning endurance itself. If the entity in question is a perdurant then the rigidity claim is trivial, though one is left wondering how it (...) is that different speakers ever manage to pick out one and the same entity when a host of suitable, overlapping candidates are available. But what if the entity in question is neither a continuant nor a perdurant? What if the things we talk about in ordinary language are time-bound entities that cannot truly be said to persist through time, or stage sequences whose unity resides exclusively in our minds--like the “waves” at the stadium or the characters of a cartoon? In such cases the rigidity claim can’t be right and a counterpart-theoretic semantics seems required. Is that bad? I say it isn’t. And it had better not be, if that turns out to be the best metaphysical option we have. (shrink)

Standard lore has it that a proper name, or a definite description on its de re reading, is a temporally rigid designator. It picks out the same entity at every time at which it picks out an entity at all. If the entity in question is an enduring continuant then we know what this means, though we are also stuck with a host of metaphysical puzzles concerning endurance itself. If the entity in question is a perdurant then the rigidity claim (...) is trivial, though one is left wondering how it is that different speakers ever manage to pick out one and the same entity when a host of suitable, overlapping candidates are available. But what if the entity in question is neither a continuant nor a perdurant? What if the things we talk about in ordinary language are time‐bound entities that cannot truly be said to persist through time, or stage sequences whose unity resides exclusively in our minds ‐ like the “wave” at the stadium or the characters of a cartoon? In such cases the rigidi‐ ty claim can't be right and a counterpart‐theoretic semantics seems required. Is that bad? I say it isn't. And it had better not be, if that turns out to be the best metaphysical option we have. (shrink)

David Lewis’s counterpart theory is often seen as involving a radical departure from the standard, Kripke-style semantics for modal logic, suggesting that we are dealing with deeply divergent accounts of our modal talk. However, CT captures but one version of the relevant semantic intuition, and does so on the basis of metaphysical assumptions that are ostensibly discretionary. Just as ML can be translated into a language that quantifies explicitly over worlds, CT may be formulated as a semantic theory in which (...) world quantification is purely metalinguistic. And just as Kripke-style semantics is formally compatible with the doctrine of world-boundedness, a counterpart-based semantics may in principle allow for cases of trans-world identity. In fact, one may welcome a framework that is general enough to include both Lewis’s counterpart-based account and Kripke’s identity-based account as distinguished special cases. There are several ways of doing so. The purpose of this paper is to outline a fully general option and to illustrate its philosophical significance, showing how the large variety of intermediate relations that lie between Lewisian counterparthood and Kripkean identity yield a corresponding variety of modal theories that would otherwise remain uncharted. (shrink)

In this paper, I defend modal dimensionalism against the objection that it is ontologically and ideologically heavy. First, I briefly outline the theory and the objection against it. The objection relies on the widely accepted view that ontological and ideological parsimony are operational criteria when comparing metaphysical theories. Second, I outline the conventional distinction between ontology and ideology in the metaphysical tradition. Third, I challenge a particular kind of parsimony: reduction by identification. Fourth, even if reduction by identification is accepted, (...) I show that theories that pursue this often minimize differences, and that such minimization paves the way to epistemic underdetermination. Finally, I demonstrate that some theories in modal metaphysics also suffer from difference minimization and should thus not be measured on the ontology/ideology scale. (shrink)

Kai Wehmeier’s Wittgensteinian Predicate Logic is a formulation of first-order logic under the exclusive interpretation of the quantifiers. W-logic has a distinguished relation constant for co-reference but no sign for objectual identity. Wehmeier denies that objectual identity exists on the grounds that it cannot be a genuine binary relation. Fortunately W-logic is equi-expressive with standard first-order logic with identity and it appears that objectual identity is dispensable across the broader logical enterprise. This paper challenges the latter claim as objectual identity (...) seems to be needed in the exclusive interpretation of quantified modal logic, specifically, for implementing certain kinds of de re quantification. (shrink)

Classical modalism about essence is the view that essence can be analysed in modal terms. Despite Kit Fine's influential critique, no general refutation of classical modalism has yet been given. In the first part of the paper, I provide such a refutation by showing that the notion of essence cannot be analysed in terms of any sentential operator definable in the language of standard quantified modal logic. As a reaction to Fine's critique, some have defended sophisticated modalism, which attempts to (...) analyse essence in an enriched modal language quantifying over both possible and impossible worlds. In the second part of the paper, I argue that sophisticated modalism falls prey to variations on Fine's counterexamples to classical modalism. I conclude that the most promising approaches to understanding the notion of essence consist in taking essence either as primitive or as analysable via a combination of modal and non-modal notions. (shrink)

Lewis proposed to test the validity of a modal thesis by checking whether its possible-world translation is a theorem of counterpart theory. However, that criterion fails to validate many standard modal laws, thus raising doubts about the logical adequacy of the Lewisian framework. The present paper considers systems of counterpart theory of increasing strength and shows how each can be motivated by exhibiting a suitable intended model. In particular, perfect counterpart theory validates all the desired modal laws and therefore provides (...) a way out of the logical objection. Finally, a weakening of perfect counterpart theory is put forward as a response to some metaphysical objections. (shrink)

I introduce and defend the semantic notion of counterfactual identity, distinguishing it from the metaphysical notion of transworld identity. After showing that Lewis's counterpart theory misconstrues counterfactual identity facts, I outline and motivate a ‘Leibnizian counterpart theory’ where the notion of counterfactual identity is adequately modelled. Finally, I show that counterfactual identity can be characterized without relying on some implausible features of Lewis's theory of conditionals.

On one influential view, metaphysical fundamentality can be understood in terms of joint‐carving. Ted Sider has recently argued that (i) some first order quantifier is joint‐carving, and (ii) modal notions are not joint‐carving. After vindicating the theoretical indispensability of quantification against recent criticism, I will defend a logical result due to Arnold Koslow which implies that (i) and (ii) are incompatible. I will therefore consider an alternative understanding of Sider's metaphysics to the effect that (i) some first order quantifier is (...) joint‐carving, and (iii) intensional notions are not joint‐carving. Another result due to Koslow entails that (i) and (iii) are also incompatible. I will argue that this second result is inconclusive. Nevertheless, (iii) is incompatible with another tenet of Sider's metaphysics, namely that (iv) ‘being joint‐carving’ is itself joint‐carving. In order to resolve the inconsistency, I will tentatively argue that condition (iv) should be renounced. (shrink)

It has been argued that a combination of game-theoretic semantics and independence-friendly (IF) languages can provide a novel approach to the conceptual foundations of mathematics and the sciences. I introduce and motivate an IF first-order modal language endowed with a game-theoretic semantics of perfect information. The resulting interpretive independence-friendly logic (IIF) allows to formulate some basic model-theoretic notions that are inexpressible in the ordinary quantified modal logic. Moreover, I argue that some key concepts of Kripke’s new theory of reference are (...) adequately modeled within IIF. Finally, I compare the logic IIF to David Lewis' counterpart theory, drawing some morals concerning the interrelation between metaphysical and semantic issues in possible-world semantics. (shrink)

Anti-haecceitism is the thesis that things cannot differ from actuality in a purely non-qualitative fashion. Anti-haecceitism being a modal notion, we would expect it to be explicable in terms of possible worlds. Bradford Skow denied that, arguing that alternative conceptions of possible worlds prompt non-equivalent characterizations of anti-haecceitism. Therefore, the haecceitism debate should take place in the modal language, rather than in the language of possible worlds. The aim of this paper is to provide a metaphysically neutral possible-world characterization of (...) anti-haecceitism, i.e. one compatible with alternative understandings of the nature of possible worlds. (shrink)

Some essence facts have metaphysical explanations. Some metaphysical explanations for essence facts consist in nonessential facts.

Nonreductive physicalism faces serious problems regarding causal exclusion, causal heterogeneity, and the nature of realization. In this paper I advance solutions to each of those problems. The proposed solutions all depend crucially on embracing modal counterpart theory. Hence, the paper’s thesis: counterpart theory saves nonreductive physicalism. I take as my inspiration the view that mental tokens are constituted by physical tokens in the same way statues are constituted by lumps of clay. I break from other philosophers who have pursued this (...) line, however, in that I hold that constitution is identity. Much of the value of the comparison to statues and lumps is that it calls to mind the resources used to defend constitution-as-identity, most notably that of counterpart theory. Along the way, I discuss the virtues of a trope ontology, modal objections to token identity theories, the prospects of conditional analyses of causal powers, the subset account of realization, and the grounding problem. I also endorse a novel, empirical argument in favor of counterpart theory. (shrink)

A general meta-logical theory is developed by considering ontological disputes in the systems of metaphysics. The usefulness of this general meta-logical theory is demonstrated by considering the case of the ontological dispute between the metaphysical systems of Lewis’ Modal Realism and Terence Parsons’ Meinongianism. Using Quine’s criterion of ontological commitments and his views on ontological disagreement, three principles of metalogic is formulated. Based on the three principles of metalogic, the notions of independent variable and dependent variable are introduced. Then, the (...) ontological dispute between Lewis’ Modal Realism and Terence Parsons’ Meinongianism are restated in the light of the principles of metalogic. After the restatement, Independent variable and dependent variables are fixed in both Lewis’ Modal Realism and Terence Parsons’ Meinongianism to resolve the dispute. Subsequently, a new variety of quantifiers are introduced which is known as functionally isomorphic quantifiers to provide a formal representation of the resolution of the dispute. The specific functionally isomorphic quantifier which is developed in this work is known as st-quantifier. It is indicated that how st-quantifier which is one of the functionally isomorphic quantifiers can function like existential quantifier. It is also shown that there is some kind of inconsistency which is unavoidable in stating the ontological disagreement and therefore, paraconsistent logic is a requirement in stating the ontological disputes. (shrink)

This paper first argues that we can bring out a tension between the following three popular doctrines: (i) the canonical reduction of metaphysical modality to essence, due to Fine, (ii) contingentism, which says that possibly something could have failed to be something, and (iii) the doctrine that metaphysical modality obeys the modal logic S5. After presenting two such arguments (one from the theorems of S4 and another from the theorems of B), I turn to exploring various conclusions we might draw (...) in light of these results, and argue that none comes cost free. In the course of laying out possible responses to my arguments, we'll have a chance to evaluate various doctrines about the interplay between contingency and essence, as well as develop some alternative reductions of metaphysical modality to essence. I don't decisively come down in favor of one response over the others, though I say some things that point towards the conclusion that essence has no role to play in reducing metaphysical modality. (shrink)

Objective probability in quantum mechanics is often thought to involve a stochastic process whereby an actual future is selected from a range of possibilities. Everett’s seminal idea is that all possible definite futures on the pointer basis exist as components of a macroscopic linear superposition. I demonstrate that these two conceptions of what is involved in quantum processes are linked via two alternative interpretations of the mind-body relation. This leads to a fission, rather than divergence, interpretation of Everettian theory and (...) to a novel explanation of why a principle of indifference does not apply to self-location uncertainty for a post-measurement, pre-observation subject, just as Sebens and Carroll claim. Their Epistemic Separability Principle is shown to arise out of this explanation and the derivation of the Born rule for Everettian theory is thereby put on a firmer footing. (shrink)

How does it come about then, that great scientists such as Einstein, Schrödinger and De Broglie are nevertheless dissatisfied with the situation? Of course, all these objections are levelled not against the correctness of the formulae, but against their interpretation. [...] The lesson to be learned from what I have told of the origin of quantum mechanics is that probable refinements of mathematical methods will not suffice to produce a satisfactory theory, but that somewhere in our doctrine is hidden a (...) concept, unjustified by experience, which we must eliminate to open up the road. (Born [ 1954 ], pp. 8, 11) It is truly surprising how little difference all this makes. Most physicists use quantum mechanics every day in their working lives without needing to worry about the fundamental problem of its interpretation. (Weinberg [ 1992 ], p. 66) I endorse the view that it may be of no relevance to the acceptability of the Everett interpretation of quantum mechanics as a physical theory whether or not an informed observer can be uncertain about the outcome of a quantum measurement prior to its having occurred. However, I suggest that the very possibility of post-measurement, pre-observation uncertainty has an essential role to play in both confirmation theory and decision theory in a branching universe. This is supported by arguments which do not appeal to van Fraassen’s Reflection Principle. (shrink)

Some analyses of personal fission suggest that an informed subject should expect to have a distinct experience of each outcome simultaneously. Is rational provision for the future possible in such unfamiliar circumstances? I argue that, with some qualification, the subject can reasonably act as if faced with alternative possible outcomes with precise probabilities rather than multiple actual outcomes.

In the paper we introduce a wide range of Anderson-like variants of Gödel's theory and prove for each of them strong completeness theorem wrt. corresponding class of modal structures.These theories — all formulated in the 2nd order modal language with a 2nd order unary predicate of positiveness — differ among themselves with respect of: properties of the necessity operator and of the predicate of positiveness, axioms characterizing identity between 1st sort terms, definitions of identity between 2nd sort terms, the treatment (...) of Godlikeness as a term of the 2nd order, the treatment of necessary existence as a term of the 2nd order if there exists the necessity of its presence, the treatment of Ix (Ix(y) is read: terms x, y are identical), for every 1st sort term x, as a term of the 2nd order if there exists the necessity of its presence.Concerning to semantical commitments, the following are essential: (i) 1st order terms order receive only rigid extensions in the constant objectual 1st order domain; (ii) 2nd order terms receive non-rigid extensions in the constant objectual domain of 2nd order and rigid intensions in the constant conceptual 2nd order domain; (iii) The behavior of the identity between 1st sort terms shifts from possible worlds to possible worlds. (shrink)

In this paper I argue that questions about the semantics of rigid designation are commonly and illicitly run together with distinct issues, such as questions about the metaphysics of essence and questions about the theoretical legitimacy of the possible-worlds framework. I discuss in depth two case studies of this phenomenon – the first concerns the relation between rigid designation and reference, the second concerns the application of the notion of rigidity to general terms. I end by drawing out some conclusions (...) about the relations between rigid designation, semantic frameworks, reference, and essence. (shrink)