Certain passages in Kaplan’s ‘Demonstratives’ are often taken to show that non-vacuous sentential operators associated with a certain parameter of sentential truth require a corresponding relativism concerning assertoric contents: namely, their truth values also must vary with that parameter. Thus, for example, the non-vacuity of a temporal sentential operator ‘always’ would require some of its operands to have contents that have different truth values at different times. While making no claims about Kaplan’s intentions, we provide several reconstructions of how such (...) an argument might go, focusing on the case of time and temporal operators as an illustration. What we regard as the most plausible reconstruction of the argument establishes a conclusion similar enough to that attributed to Kaplan. However, the argument overgenerates, leading to absurd consequences. We conclude that we must distinguish assertoric contents from compositional semantic values, and argue that once they are distinguished, the argument fails to establish any substantial conclusions. We also briefly discuss a related argument commonly attributed to Lewis, and a recent variant due to Weber. (shrink)

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)

This essay considers Kant’s theory of modality in light of a debate in contemporary modal metaphysics and modal logic concerning the Barcan formulas. The comparison provides a new and fruitful perspective on Kant’s complex and sometimes confusing claims about possibility and necessity. Two central Kantian principles provide the starting point for the comparison: that the possible must be grounded in the actual and that existence is not a real predicate. Both are shown to be intimately connected to the Barcan formulas, (...) and Kant’s views on what he distinguishes as three different kinds of modality are then considered in light of this connection. (shrink)

In this paper, I examine our intuitive understanding of metaphysical contingency, and ask what features a metaphysical picture must possess in order to satisfy our intuitions about modal matters. After spelling out what I think are the central intuitions in this domain, I examine the debate between the two most widely held views on the nature of modality, namely, modal realism and modal actualism. I argue that while each of these views is able to accommodate some of our intuitions, it (...) leaves others unsatisfied. I then present an alternative metaphysical picture, which I argue can accommodate our intuitions in a way that the traditional views cannot. More specifically, I argue that our intuitions about modality call for a pluralist view of the structure of reality—a view on which there is more than one ultimate ‘shape’ to the fundamental facts, each corresponding to a distinct metaphysically privileged perspective on reality. (shrink)

In the tradition of quantified modal logic, it was assumed that significantly different linguistic systems underlie reference to individuals, to times and to ‘possible worlds’. Various results from recent research in formal semantics suggest that this is not so, and that there is in fact apervasive symmetrybetween the linguistic means with which we refer to these three domains. Reference to individuals, times and worlds is uniformly effected through generalized quantifiers, definite descriptions, and pronouns, and in each domain grammatical features situate (...) the reference of terms as near, far or ‘further’ from the actual or from a reported speech act. We outline various directions in which a program ofontological symmetrycould be developed, and we offer in theAppendixa symmetric fragment developed in a logic that can be seen as a compromise between an extensional and an intensional system. (shrink)

In the tradition of quantified modal logic, it was assumed that significantly different linguistic systems underlie reference to individuals, to times and to 'possible worlds'. Various results from recent research in formal semantics suggest that this is not so, and that there is in fact a pervasive symmetry between the linguistic means with which we refer to these three domains. Reference to individuals, times and worlds is uniformly effected through generalized quantifiers, definite descriptions, and pronouns, and in each domain grammatical (...) features situate the reference of terms as near, far or 'further' from the actual or from a reported speech act. We outline various directions in which a program of ontological symmetry could be developed, and we offer in the Appendix a symmetric fragment developed in a logic that can be seen as a compromise between an extensional and an intensional system. (shrink)

Kaplan (drawing on Montague and Prior, inter alia) made explicit the idea of world and time neutral propositions, which bear truth values only relative to world and time parameters. There was then a debate over the role of time. Temporalists sided with Kaplan in maintaining time neutral propositions with time relative truth values, while eternalists claimed that all propositions specify the needed time information and so bear the same truth value at all times. But there never was much of a (...) parallel debate over the role of worlds. Let contingentism be the view (parallel to temporalism) that sides with Kaplan in maintaining world neutral propositions with world relative truth values, and let necessitarianism be the view (parallel to eternalism) that propositions specify the needed world information and so bear the same truth value at all worlds. This is the story of how the debate between the contingentists and the necessitarians might begin. (shrink)

ABSTRACT Quine insisted that the satisfaction of an open modalised formula by an object depends on how that object is described. Kripke's ‘objectual’ interpretation of quantified modal logic, whereby variables are rigid, is commonly thought to avoid these Quinean worries. Yet there remain residual Quinean worries for epistemic modality. Theorists have recently been toying with assignment-shifting treatments of epistemic contexts. On such views an epistemic operator ends up binding all the variables in its scope. One might worry that this yields (...) the undesirable result that any attempt to ‘quantify in’ to an epistemic environment is blocked. If quantifying into the relevant constructions is vacuous, then such views would seem hopelessly misguided and empirically inadequate. But a famous alternative to Kripke's semantics, namely Lewis' counterpart semantics, also faces this worry since it also treats the boxes and diamonds as assignment-shifting devices. As I'll demonstrate, the mere fact that a variable is bound is no obstacle to binding it. This provides a helpful lesson for those modelling de re epistemic contexts with assignment sensitivity, and perhaps leads the way toward the proper treatment of binding in both metaphysical and epistemic contexts: Kripke for metaphysical modality, Lewis for epistemic modality. (shrink)

This paper elaborates the problem of temporal unity for dynamic presentism and diagnoses the source of that problem in the dynamic presentist’s discarding the traditional C-series in its avoidance of McTaggart’s (1908, 1927) A-series paradox. This C-series provided the fixed structure of time which the transitory aspects of time then followed, and thereby unify those transitory aspects. It then considers ersatzer presentism as an ostensible solution to the problem of temporal unity by providing a new abstract C-series (namely an ersatz-B-series) (...) for dynamic presentism. However, after a closer examination of the details of this proposal, it is found that the ersatz-B-series itself needs to be temporally variable to capture the transitory aspects of time that it is meant to track. Consequently, it cannot provide the fixed structure of time required to unify the transitory aspects of time into a temporal series. It is therefore suggested that dynamic presentists look for a more course-grained determiner of temporal progression to construct the presentist-friendly C-series required to unify their transitory aspects of time. (shrink)

Drawing upon a conception of the metaphysics of conscious states and of first-person content, we can argue that Descartes's transition ‘Cogito ergo sum’ is both sound and one he is entitled to make. We can nevertheless formulate a version of Lichtenberg's objection that can still be raised after Bernard Williams's discussion. I argue that this form of Lichtenberg's revenge can also be undermined. In doing so it helps to compare the metaphysics of subjects, worlds and times. The arguments also apply (...) to Descartes's ‘second Cogito’, that it is one and the same subject that thinks, wills, imagines. (shrink)

Traditionally, the formulae in modal logic express properties of possible worlds. Prior introduced “egocentric” logics that capture properties of agents rather than of possible worlds. In such a setting, the article proposes the modality “know how to tell apart” and gives a complete logical system describing the interplay between this modality and the knowledge modality. An important contribution of this work is a new matrix-based technique for proving completeness theorems in an egocentric setting.

Hybrid languages are introduced in order to evaluate the strength of “minimal” mereologies with relatively strong frame definability properties. Appealing to a robust form of nominalism, I claim that one investigated language \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\mathcal {H}_{\textsf {m}}$\end{document} is maximally acceptable for nominalistic mereology. In an extension \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\mathcal {H}_{\textsf {gem}}$\end{document} of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\mathcal {H}_{\textsf {m}}$\end{document}, a modal analog (...) for the classical systems of Leonard and Goodman and Leśniewski is introduced and shown to be complete with respect to 0-deleted Boolean algebras. We characterize the formulas of first-order logic invariant for \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\mathcal {H}_{\textsf {gem}}$\end{document}-bisimulations. (shrink)

This paper presents a distinctively metaphysical version of the problem of other minds. The main source of this version of the problem lies in the principle that, when it comes to consciousness, no distinction can sensibly be drawn between appearance and reality. I will argue that, unless we want to call that principle into question, we should seriously consider the possibility of accepting the conclusion that other minds are not like our own. This option is less problematic than it might (...) seem at first if we are willing to reconceive facts of consciousness as subjective rather than objective in nature. -/- . (shrink)

This paper defends the view that one's own mental states are metaphysically privileged vis-à-vis the mental states of others, even if only subjectively so. This is an instance of a more general view called Subjectivism, according to which reality is only subjectively the way it is. After characterizing Subjectivism in analogy to two relatively familiar views in the metaphysics of modality and time, I compare the Subjectivist View of the Mental with Egocentric Presentism, a version of Subjectivism recently advocated by (...) Caspar Hare. I argue that the Subjectivist View of the Mental goes a considerable way towards solving certain long-standing philosophical puzzles having to do with the unity of consciousness, the contents of self-awareness and the intransmissibility of experiential knowledge through testimony. (shrink)

The fundamental principle of the theory of possible worlds is that a proposition p is possible if and only if there is a possible world at which p is true. In this paper we present a valid derivation of this principle from a more general theory in which possible worlds are defined rather than taken as primitive. The general theory uses a primitive modality and axiomatizes abstract objects, properties, and propositions. We then show that this general theory has very small (...) models and hence that its ontological commitments—and, therefore, those of the fundamental principle of world theory—are minimal. (shrink)

This paper sketches a new and somewhat heterodox metaphysical theory of consciousness: the “many-worlds theory”. It drops the assumption that all conscious subjects’ experiences are features of one and the same world and instead associates different subjects with different “first-personally centred worlds”. We can think of these as distinct “first-personal realizers” of a shared “third-personal world”, where the latter is supervenient, in a sense to be explained. This is combined with a form of modal realism, according to which different subjects’ (...) first-personally centred worlds are all real, though only one of them is present for each subject. The theory offers a novel way of capturing the irreducibly subjective nature of conscious experience without lapsing into solipsism. The paper also looks at some scientific theories of consciousness, such as integrated information theory, through the proposed lens and reconsiders the hard problem of consciousness. (shrink)

The starting point of this paper is the thought that the phenomenal appearances that accompany mental states are somehow only there, or only real, from the standpoint of the subject of those mental states. The world differs across subjects in terms of which appearances obtain. Not only are subjects standpoints across which the world varies, subjects are standpoints that we can ‘adopt’ in our own theorizing about the world (or stand back from). The picture that is suggested by these claims (...) has an appeal but is at the same time obscure and stands in need of regimentation. This paper explores and motivates a metaphysical account of what it is for subjects to be standpoints, what it is to adopt standpoints in our representations and, most importantly, how these notions might help us better understand the subjective character of conscious mental states. Some well-known observations by Thomas Nagel serve as starting points and the paper concludes by revisiting Nagel’s argument for the inevitable incompleteness of objective accounts of mental states, which will be reframed in terms of the central commitments of the proposed framework. (shrink)

Montague, Prior, von Wright and others drew attention to resemblances between modal operators and quantifiers. In this paper we show that classical quantifiers can, in fact, be regarded as S5-like operators in a purely propositional modal logic. This logic is axiomatized and some interesting fragments of it are investigated.

We shall try to defend two non-standard views that run counter to two well-entrenched familiar views. The standard views are the universal and existential quantifiers of first-order logic are not modal operators, and the quantifiers are extensional. If that is correct then the counterclaims create genuine problems for some traditional philosophical doctrines.

A. N. Prior very much admired the logic and philosophy of C.S. Peirce. In the spring of 1962 Prior went to Chicago to study Peirce's ideas. One of the topics that caught his attention was Peirce's existential graphs. This interest continued when he returned to England. In this paper Prior's grappling with the existential graphs will be discussed.

Propositional modal logic over relational frames is naturally extended with propositional quantifiers by letting them range over arbitrary sets of worlds of the relevant frame. This is also known as second-order propositional modal logic. The propositionally quantified modal logic of a class of relational frames is often not axiomatizable, although there are known exceptions, most notably the case of frames validating the strong modal logic$\mathrm {S5}$. Here, we develop new general methods with which many of the open questions in this (...) area can be answered. We illustrate the usefulness of these methods by applying them to a range of examples, which provide a detailed picture of which normal modal logics define classes of relational frames whose propositionally quantified modal logic is axiomatizable. We also apply these methods to establish new results in the multimodal case. (shrink)

I argue for a version of tense-logical realism that privileges tensed facts without privileging any particular temporal standpoint from which they obtain.

This paper is part of a general programme of developing and investigating particular first- order modal theories. In the paper, a modal theory of propositions is constructed under the assumption that there are genuinely singular propositions, ie. ones that contain individuals as constituents. Various results on decidability, axiomatizability and definability are established.

Logics of discrete time are, in Arthur Prior’s words, “applicable in limited fields of discourse in which we are concerned with what happens in a sequence of discrete states,” independent of “any serious metaphysical assumption that time is discrete.” This insight is applied to natural language semantics, a widespread assumption in which is that time is, as is the real line, dense. “Limited fields of discourse” are construed as finite sets of temporal propositions, inducing bounded notions of temporal granularity that (...) can be refined to expand the discourse. The construal is developed in line with Prior’s view of what is “metaphysically fundamental”. (shrink)

In his seminal work, McTaggart :457–484, 1908; The nature of existence, Cambridge University Press, Cambridge, 1927) dismissed the possibility of understanding the B-Relations as irreducibly temporal relations, and with it dismissing the B-Theory of time, which assumes the reality of irreducible B-relations. Instead, he thought they were mere constructions from irreducible A-determinations and timeless ordering relations. However, since, philosophers have almost universally dismissed his dismissal of irreducible B-relations. This paper argues that McTaggart was correct to dismiss the possibility of B-relations, (...) and that would be B-theorists should be C-theorists and its concomitant commitment to the unreality of time. I do this by first elaborating C-Theory, noting that B-relations appear indiscernible from C-relations on close examination. This establishes an onus on B-theorists to distinguish B-relations from C-relations by elaborating the distinctively temporal character of the former. I then present a problem for the possibility of accommodating temporal character in B-relations. Following this, I question from whence derives our sense of the temporal character that purportedly resides in the irreducible B-relations. Finally, I extend the challenge against irreducible B-relations to a series of irreducible abstract temporal relations—so called Ersatz-B-Relations—modelled on them. (shrink)

This paper elaborates the problem of temporal unity for dynamic presentism and diagnoses the source of that problem in the dynamic presentist’s discarding the traditional C-series in its avoidance of McTaggart’s A-series paradox. This C-series provided the fixed structure of time which the transitory aspects of time then followed, and thereby unify those transitory aspects. It then considers ersatzer presentism as an ostensible solution to the problem of temporal unity by providing a new abstract C-series for dynamic presentism. However, after (...) a closer examination of the details of this proposal, it is found that the ersatz-B-series itself needs to be temporally variable to capture the transitory aspects of time that it is meant to track. Consequently, it cannot provide the fixed structure of time required to unify the transitory aspects of time into a temporal series. It is therefore suggested that dynamic presentists look for a more course-grained determiner of temporal progression to construct the presentist-friendly C-series required to unify their transitory aspects of time. (shrink)

In celebrating Arthur Prior we celebrate what he gave to the world. Much of this is measured by what others have made of his ideas after his death. The focus of this paper is a little different. It looks at what Prior himself thought he was accomplishing. In particular it considers Prior’s attitude to the semantic metatheory of the logics that he was interested in. The paper sets out some characteristics of the metalogical study of intensional languages in terms of (...) an indexical theory of truth conditions stated in the language of set theory. In examining Prior’s work using these characteristics, it emerges that Prior had serious reservations about this way of studying modal and tense logics. (shrink)

According to First-Person Realism, one's own first-person perspective on the world is metaphysically privileged in some way. After clarifying First-Person Realism by reference to parallel debates in the metaphysics of modality and time, I survey eight different arguments in favor of First-Person Realism.

Most of us would want to say that it is true that Socrates taught Plato. According to realists about past facts,1 this is made true by the fact that there is, located in the past, i.e., earlier than now, at least one real event that is the teaching of Plato by Socrates. Presentists, however, in denying that past events and facts exist2 cannot appeal to such facts to make their past-tensed statements true. So what is a presentist to do?

The paper presents a novel version of universalism—the thesis according to which there are only universals, no individuals—which is cashed out in terms of an adverbial analysis of predication. According to the theory, every spatiotemporal occurrence of a universal U can be expressed by a sentence which asserts the existence of U adverbially modified by the spatiotemporal region at which it exists. After some preliminary remarks on the interpretation of natural language, a formal semantics for the theory is first provided, (...) along with an intended interpretation of its key metaphysical imports. Follow some commentaries on the spatiotemporal manifold and determinable properties. (shrink)

The verb 'knows' is often taken to be context-sensitive in an interesting way. What 'knows' means seems to be sensitive to the epistemic features of the context, e.g. the epistemic standard in play, the set of relevant alternatives, etc. There are standard model-theoretic semantic frameworks which deal with both intensional operators and context-sensitive expressions. In this chapter, we provide a brief overview of the various moving parts of these frameworks, the roles of context and index, the need for double indexing, (...) and the relationship between semantic value and content. With the best version of the standard framework explicated we then return at the end to the treatment of ‘know’ as a context-sensitive intensional operator (contrasting it with an invariantist treatment). (shrink)

I attend to the debate between the A-theory of time and the B- theory of time by evaluating how each theory accounts for the possibility of change. I conclude in favour of the B-theory of time as an account of change. I begin by considering McTaggart’s argument against the reality of time. I connect McTaggart’s argument, and the attendant A-theory versus B-theory debate, to an argument against the possibility of change. This argument, the problem of change, can be refuted by (...) adopting either of an A-theory or B-theory account of change. I evaluate different approaches to change offered by various A-theories, including presentism, the growing block theory, the moving spotlight theory, and then proceed to consider different B-theory accounts of change, including relativiser endurantism, adverbialist endurantism, and perdurantism. I consider objections to each of these views. Finally, I compare the costs incurred by the best of the A-theory accounts and the best of the B-theorist accounts. (shrink)

Non-reductivists about phenomenal consciousness believe that physical facts are insufficient to ground the existence of phenomenal consciousness. It will be argued that if one is going to be a non-reductivist, then one should not limit oneself to expanding one’s catalogue of the world’s basic features, as recommended in the paradigmatic non-reductivist approach developed by David Chalmers. One should rather take a realist stance towards subjectivity. A realist about subjectivity thinks that at least some of the propositions needed to state how (...) things are in reality are such that their truth-value is capable of changing ‘from one subject to another’. Realism about subjectivity will be introduced by means of an analogy with the so called ‘A-theory’ of time. An A-theorist claims that at least some of the propositions needed to state how things are in reality are such that their truth-value is capable of changing ‘from one time to another’. It turns out that a robust notion of metaphysical reality is necessary to make sense of both realism about subjectivity and the A-theories of time. (shrink)

The first part of this thesis articulates and defends the Subjectivist View of the Mental. According to this view, my mental states are essentially different from the mental states of everyone else, but the fact that they are is a subjective fact, rather than an objective one. Chapter 1 explains what it takes for a fact to be subjective, what kind of difference holds between my mental states and everyone else's mental states and what kind of intuitions lead me to (...) believe that there is such a difference. Chapter 2 defends the Subjectivist View of the Mental from objections and discusses some of its most significant implications. In the second part of the thesis, I explore the advantages that the Subjectivist View of the Mental offers when it comes to accounting for three basic features of our knowledge of the mental. Chapter 3 deals with the asymmetry between self-knowledge and knowledge of other minds. It is argued that, if the Subjectivist View of the Mental is true, we can explain why this asymmetry holds without assuming that self-knowledge and knowledge of other minds are involved with substantially different ways of knowing. Chapter 4 focuses on the immunity to error through misidentification of mental self-ascriptions. I show that, while there has been a temptation to explain this phenomenon by following Lichtenberg and Wittgenstein in taking the content of mental self-ascriptions to be general rather than particular, this proposal cannot be made to work unless something like the Subjectivist View of the Mental is true. Chapter 5 is concerned with experiential knowledge. I argue that, if experiential truths are taken to be objective truths, it is not easy to see why experiential knowledge should have the peculiar 'first-hand' character it has. The problem disappears if experiential truths are regarded as subjective rather than objective. (shrink)

Human beings seem to capture time and the temporal properties of events and things in thought by having beliefs usually expressed with statements using tense, or notions such as ‘now’, ‘past’ or ‘future’. Tensed beliefs like these seem indispensable for correct reasoning and timely action. For instance, my belief that my root canal is over seems inexpressible with a statement that does not use tense or a temporal indexical. However, the dominant view on the nature of time is that it (...) forms, with space, a four-dimensional continuum where time does not encompass private perspectives or an absolute, fixed present. This ‘tenseless’ theory of time encounters a challenge in integrating tensed belief, because it cannot easily explain what constitutes a tensed belief in a tenseless world and how such a belief works inside our cognitive network to bring about the actions it does. Providing such an account is the main goal of this dissertation. -/- I argue here that the correct way to proceed would be to utilize philosophical theories dealing with indexicality, as the puzzling features of tensed belief are shared with beliefs expressed by first-person or spatial indexicals. In chapters II and III I expand the dominant theories about indexicality (Lewis, Perry, Kaplan) and apply them to tensed belief. I show that each is in certain respects incomplete or inadequate. -/- My preferred account critiques the preceding theories as mis-attributing the indexicality involved to a fully conceptual element in the way people think about time. I argue that we should instead connect tensed belief to not fully conceptual elements thought. For support I turn to work in perceptual psychology that connects beliefs about space to perceptions of spatial features. In chapter IV I develop an analogous argument about temporal thought and discuss how mental representations involved in perceptions are constitutively related to the formation and preservation of tensed beliefs. Combining this story with a tenseless theory of time should give us a complete, metaphysically uncontroversial, account of the way a tensed belief functions in reasoning and produces timely action. (shrink)