The paper investigates interpretations of propositional and firstorder logic in which validity is defined in terms of partial indices; sometimes called possibilities but here understood as non-empty subsets of a set W of possible worlds. Truth at a set of worlds is understood to be truth at every world in the set. If all subsets of W are permitted the logic so determined is classical first-order predicate logic. Restricting allowable subsets and then imposing certain closure conditions provides a modelling for (...) intuitionistic predicate logic. The same semantic interpretation rules are used in both logics for all the operators. (shrink)

Information exchange can be seen as a dynamic process of raising and resolving issues. The goal of this paper is to provide a logical framework to model and reason about this process. We develop an inquisitive dynamic epistemic logic , which enriches the standard framework of dynamic epistemic logic , incorporating insights from recent work on inquisitive semantics. At a static level, IDEL does not only allow us to model the information available to a set of agents, like standard epistemic (...) logic, but also the issues that the agents entertain. At a dynamic level, IDEL does not only allow us to model the effects of communicative actions that provide new information, like standard DEL, but also the effects of actions that raise new issues. Thus, IDEL provides the fundamental tools needed to analyze information exchange as a dynamic process of raising and resolving issues. (shrink)

This paper investigates the prospects for a semantic theory that treats disjunction as a modal operator. Potential motivation for such a theory comes from the way in which modals embed within disjunctions. After reviewing some of the relevant data, I go on to distinguish a variety of modal theories of disjunction. I analyze these theories by considering pairs of conflicting desiderata, highlighting some of the tradeoffs they must face.

Philosophical Logic is a clear and concise critical survey of nonclassical logics of philosophical interest written by one of the world's leading authorities on the subject. After giving an overview of classical logic, John Burgess introduces five central branches of nonclassical logic, focusing on the sometimes problematic relationship between formal apparatus and intuitive motivation. Requiring minimal background and arranged to make the more technical material optional, the book offers a choice between an overview and in-depth study, and it balances the (...) philosophical and technical aspects of the subject.The book emphasizes the relationship between models and the traditional goal of logic, the evaluation of arguments, and critically examines apparatus and assumptions that often are taken for granted. Philosophical Logic provides an unusually thorough treatment of conditional logic, unifying probabilistic and model-theoretic approaches. It underscores the variety of approaches that have been taken to relevantistic and related logics, and it stresses the problem of connecting formal systems to the motivating ideas behind intuitionistic mathematics. Each chapter ends with a brief guide to further reading.Philosophical Logic addresses students new to logic, philosophers working in other areas, and specialists in logic, providing both a sophisticated introduction and a new synthesis. (shrink)

Do logically valid arguments necessarily preserve truth? Certain inferences involving informational modal operators and indicative conditionals suggest that truth preservation and good deductive argument come apart. Given this split, I recommend an alternative to the standard truth preservation view of logic on which validity and good deductive argument coincide: logic is a descriptive science that is fundamentally concerned not with the preservation of truth, but with the preservation of structural features of information. Along the way, I defend modus ponens for (...) the indicative against an attack by Kolodny and MacFarlane, and I present a new proof system, Info, appropriate to this informational view. (shrink)

This volume collects some influential essays in which Simon Blackburn, one of our leading philosophers, explores one of the most profound and fertile of philosophical problems: the way in which our judgments relate to the world. This debate has centered on realism, or the view that what we say is validated by the way things stand in the world, and a variety of oppositions to it. Prominent among the latter are expressive and projective theories, but also a relaxed pluralism that (...) discourages the view that there are substantial issues at stake. The figure of the "quasi-realist" dramatizes the difficulty of conducting these debates. Typically philosophers thinking of themselves as realists will believe that they alone can give a proper or literal account of some of our attachments--to truth, to facts, to the independent world, to knowledge and certainty. The quasi-realist challenge, developed by Blackburn in this volume, is that we can have those attachments without any metaphysic that deserves to be called realism, so that the metaphysical picture that goes with our practices is quite idle. The cases treated here include the theories of value and knowledge, modality, probability, causation, intentionality and rule-following, and explanation. A substantial new introduction has been added, drawing together some of the central themes. The essays articulate a fresh alternative to a primitive realist/anti-realist opposition, and their cumulative effect is to yield a new appreciation of the delicacy of the debate in these central areas. (shrink)

The article proposes an analysis of imperatives and possibility and necessity statements that (i) explains their differences with respect to the licensing of free choice any and (ii) accounts for the related phenomena of free choice disjunction in imperatives, permissions, and statements. Any and or are analyzed as operators introducing sets of alternative propositions. Free choice licensing operators are treated as quantifiers over these sets. In this way their interpretation can be sensitive to the alternatives any and or introduce in (...) their scope. (shrink)

The book presents a new logical framework to capture the meaning of sentences in conversation. It is based on a richer notion of meaning than traditional approaches, and allows for an integrated treatment of statements and questions. The first part of the book presents the framework in detail, while the second demonstrates its many benefits.

John MacFarlane explores how we might make sense of the idea that truth is relative. He provides new, satisfying accounts of parts of our thought and talk that have resisted traditional methods of analysis, including what we mean when we talk about what is tasty, what we know, what will happen, what might be the case, and what we ought to do.

Russell and Strawson sparked a well known debate on the subject of Linguistic Presupposition inspiring many linguists and philosophers to follow suit, including Frege, whose work initiated the modern study in this area. Beaver begins with the most comprehensive overview and critical discussion of this burgeoning field published to date. He then goes on to motivate and develop his own account based on a Dynamic Semantics. This account is a recent line of theoretical work in which the Tarskian emphasis on (...) truth conditions is questioned. The central plank of the theory of meaning is a formal account of the change in information effected by use of language on hearers or readers. The proposal thus consolidates ideas of Stalnaker, Karttunen and Heim, all of whom had suggested that such an account was needed. At the same time it provides a new impulse and motivation to Dynamic Semantics itself. (shrink)

Traditional philosophical discussions of knowledge have focused on the epistemic status of full beliefs. In this book, Moss argues that in addition to full beliefs, credences can constitute knowledge. For instance, your .4 credence that it is raining outside can constitute knowledge, in just the same way that your full beliefs can. In addition, you can know that it might be raining, and that if it is raining then it is probably cloudy, where this knowledge is not knowledge of propositions, (...) but of probabilistic contents. -/- The notion of probabilistic content introduced in this book plays a central role not only in epistemology, but in the philosophy of mind and language as well. Just as tradition holds that you believe and assert propositions, you can believe and assert probabilistic contents. Accepting that we can believe, assert, and know probabilistic contents has significant consequences for many philosophical debates, including debates about the relationship between full belief and credence, the semantics of epistemic modals and conditionals, the contents of perceptual experience, peer disagreement, pragmatic encroachment, perceptual dogmatism, and transformative experience. In addition, accepting probabilistic knowledge can help us discredit negative evaluations of female speech, explain why merely statistical evidence is insufficient for legal proof, and identify epistemic norms violated by acts of racial profiling. Hence the central theses of this book not only help us better understand the nature of our own mental states, but also help us better understand the nature of our responsibilities to each other. (shrink)

This paper offers an explanation of the fact that sentences of the form (1) ‘X may A or B’ may be construed as implying (2) ‘X may A and X may B’, especially if they are used to grant permission. It is suggested that the effect arises because disjunctions are conjunctive lists of epistemic possibilities. Consequently, if the modal may is itself epistemic, (1) comes out as equivalent to (2), due to general laws of epistemic logic. On the other hand, (...) on a deontic reading of may, (2) is only implied under exceptional circumstances – which usually obtain when (1) is used performatively. (shrink)

Expressivists and relativists about epistemic modals often motivate their view by arguing against contextualist treatments of certain cases. However, I argue that even expressivists and relativists should consider being a kind of contextualist. Specifically, data involving mixed disjunctions motivate taking epistemic modals to be sensitive to contextually-salient partitions, and thus context-sensitive.

I develop a conception of expressivism according to which it is chiefly a pragmatic thesis about some fragment of discourse, one imposing certain constraints on semantics. The first half of the paper uses credal expressivism about the language of probability as a stalking-horse for this purpose. The second half turns to the question of how one might frame an analogous form of expressivism about the language of deontic modality. Here I offer a preliminary comparison of two expressivist lines. The first, (...) expectation expressivism, looks again to Bayesian modelling for inspiration: it glosses deontically modal language as characteristically serving to express decision-theoretic expectation (expected utility). The second, plan expressivism, develops the idea (due to Gibbard 2003) that this language serves to express 'plan-laden' states of belief. In the process of comparing the views, I show how to incorporate Gibbard's modelling ideas into a compositional semantics for attitudes and modals, filling a lacuna in the account. I close with the question whether and how plan expressivism might be developed with expectation-like structure. (shrink)

Epistemic modal operators give rise to something very like, but also very unlike, Moore's paradox. I set out the puzzling phenomena, explain why a standard relational semantics for these operators cannot handle them, and recommend an alternative semantics. A pragmatics appropriate to the semantics is developed and interactions between the semantics, the pragmatics, and the definition of consequence are investigated. The semantics is then extended to probability operators. Some problems and prospects for probabilistic representations of content and context are explored.

Focusing on cases which involve binding into epistemic modals with definite descriptions and quantifiers, I raise some new problems for standard approaches to all of these expressions. The difficulties are resolved in a semantic framework that is dynamic in character. I close with a new class of problems about de re readings within the scope of modals.

This paper offers a unified semantic explanation of two observations that prove to be problematic for classical analyses of modals, conditionals, and disjunctions: the fact that disjunctions scoping under possibility modals give rise to the free choice effect and the fact that counterfactuals license simplification of disjunctive antecedents. It shows that the data are well explained by a dynamic semantic analysis of modals and conditionals that uses ideas from the inquisitive semantic tradition in its treatment of disjunction. The analysis explains (...) why embedding a disjunctive possibility under negation reverts disjunction to its classical behavior, is general enough to predict less studied simplification patterns, and also makes progress toward a unified perspective on the distinction between informative, inquisitive, and attentive content. (shrink)

This paper aims to identify the constitutive rule of assertion, conceived by analogy with the rules of a game. That assertion has such rules is by no means obvious; perhaps it is more like a natural phenomenon than it seems. One way to find out is by supposing that it has such rules, in order to see where the hypothesis leads and what it explains. That will be done here. The hypothesis is not perfectly clear, of course, but we have (...) at least a crude conception of constitutive rules, which we may refine as we elaborate the hypothesis. Although no attempt will be made here to define ‘rule’, some remarks on constitutive rules will focus the discussion. (shrink)

Assertions are praised as true, informative, relevant, sincere, warranted, well-phrased, or polite. They are criticized as false, uninformative, irrelevant, insincere, unwarranted, ill-phrased, or rude. Sometimes they deserve such praise or criticism. If any respect in which performances of an act can deserve praise or criticism is a norm for that act, then the speech act of assertion has many norms. So has almost any act; jumps can deserve praise as long or brave, criticism as short or cowardly. But it is (...) natural to suppose that some norms are more intimately connected to the nature of asserting than any norm is to the nature of jumping. One might suppose, for example, that someone who knowingly asserts a falsehood has thereby broken a rule of assertion, much as if he had broken a rule of a game; he has cheated. On this view, the speech act, like a game and unlike the act of jumping, is constituted by rules. Thus, not all norms for assertion are on a par. Norms such as relevance, good phrasing, and politeness are just applications of more general cognitive or social norms to the specific act of assertion. Perhaps the norm of informativeness results from a more complex interaction between a general norm of cooperativeness and the nature of assertion as a source of information. But on this view, not all norms for assertion derive from more general norms; otherwise nothing would differentiate it from other speech acts. (shrink)

A dynamic semantics for epistemically modalized sentences is an attractive alternative to the orthodox view that our best theory of meaning ascribes to such sentences truth-conditions relative to what is known. This essay demonstrates that a dynamic theory about might and must offers elegant explanations of a range of puzzling observations about epistemic modals. The first part of the story offers a unifying treatment of disputes about epistemic modality and disputes about matters of fact while at the same time avoiding (...) the complexities of alternative theories. The second part of the story extends the basic framework to cover some complicated data about retraction and the interaction between epistemic modality and tense. A comparison between the suggestion made in this essay and current versions of the orthodoxy is provided. (shrink)

Metaethical noncognitivists have trouble arriving at a respectable semantic theory for moral language. The goal of this article is to make substantial progress toward demonstrating that these problems may be overcome. Replacing the predominant expressivist semantic agenda in metaethics with a dynamic perspective on meaning and communication allows noncognitivists to provide a satisfying analysis of negation and other constructions that have been argued to be problematic for metaethical noncognitivism, including disjunctions. The resulting proposal preserves some of the key insights from (...) recent work on the semantics of expressivism while highlighting the widely neglected early noncognitivists' sympathies to the kind of dynamic story I intend to tell here. A comparison between the advertised dynamic semantic story and current proposals that treat expressivism as a pragmatic rather than semantic theory about moral language is provided. (shrink)

Metaethical noncognitivists have trouble arriving at a respectable semantic theory for moral language. The goal of this article is to make substantial progress toward demonstrating that these problems may be overcome. Replacing the predominant expressivist semantic agenda in metaethics with a dynamic perspective on meaning and communication allows noncognitivists to provide a satisfying analysis of negation and other constructions that have been argued to be problematic for metaethical noncognitivism, including disjunctions. The resulting proposal preserves some of the key insights from (...) recent work on the semantics of expressivism while highlighting the widely neglected early noncognitivists' sympathies to the kind of dynamic story I intend to tell here. A comparison between the advertised dynamic semantic story and current proposals that treat expressivism as a pragmatic rather than semantic theory about moral language is provided. (shrink)

The aim of this paper is twofold: (i) to introduce the framework of update semantics and to explain what kind of semantic phenomena may successfully be analysed in it: (ii) to give a detailed analysis of one such phenomenon: default reasoning.

This paper develops a compositional, type-driven constraint semantic theory for a fragment of the language of subjective uncertainty. In the particular application explored here, the interpretation function of constraint semantics yields not propositions but constraints on credal states as the semantic values of declarative sentences. Constraints are richer than propositions in that constraints can straightforwardly represent assessments of the probability that the world is one way rather than another. The richness of constraints helps us model communicative acts in essentially the (...) same way that we model agents’ credences. Moreover, supplementing familiar truth-conditional theories of epistemic modals with constraint semantics helps capture contrasts between strong necessity and possibility modals, on the one hand, and weak necessity modals, on the other. (shrink)

In this paper, the meanings of sentences containing the word or and a modal verb are used to arrive at a novel account of the meaning of or coordinations. It is proposed that or coordinations denote sets whose members are the denotations of the disjuncts; and that the truth conditions of sentences containing or coordinations require the existence of some set made available by the semantic environment which can be ‘divided up’ in accordance with the disjuncts. The relevant notion of (...) ‘dividing things up’ is made explicit in the paper. Detailed attention is given to the question of how the proposed truth conditions are derived from the syntactic input. The account offered allows for the derivation of both the disjunctive and the nondisjunctive readings of modal/or sentences, including the much-discussed free choice readings of may/or sentences. (shrink)

This paper develops a contextualist account of certain recalcitrant embedding phenomena with epistemic modals. I focus on three prominent objections to contextualism from embedding: first, that contextualism mischaracterizes subjects’ states of mind; second, that contextualism fails to predict how epistemic modals are obligatorily linked to the subject in attitude ascriptions; and third, that contextualism fails to explain the persisting anomalousness of so-called “epistemic contradictions” in suppositional contexts. Contextualists have inadequately appreciated the force of these objections. Drawing on a more general (...) framework for implementing a contextualist theory, I argue that we can derive the distinctive embedding behavior of epistemic modals from a particular contextualist interpretation of a standard semantics for modals, general mechanisms of local interpretation, and typical features of discourse contexts. Examining embedding phenomena with epistemic modals raises difficult broader issues about conventionalization and pragmatic reasoning, the varieties of context-sensitive language, and the roles of context in interpretation. The paper concludes by briefly examining how the proposed contextualist account compares with certain relativist/expressivist accounts. (shrink)

Expressivism promises an illuminating account of the nature of normative judgment. But worries about the details of expressivist semantics have led many to doubt whether expressivism's putative advantages can be secured. Drawing on insights from linguistic semantics and decision theory, I develop a novel framework for implementing an expressivist semantics that I call ordering expressivism. I argue that by systematically interpreting the orderings that figure in analyses of normative terms in terms of the basic practical attitude of conditional weak preference, (...) the expressivist can explain the semantic properties of normative sentences in terms of the logical properties of that attitude. Expressivism's problems with capturing the logical relations among normative sentences can be reduced to the familiar, more tractable problem of explaining certain coherence constraints on preferences. Particular attention is given to the interpretation of wide-scope negation. The proposed solution is also extended to other types of embedded contexts—most notably, disjunctions. (shrink)

In the 1960s, Peter Geach and John Searle independently posed an important objection to the wide class of 'noncognitivist' metaethical views that had at that time been dominant and widely defended for a quarter of a century. The problems raised by that objection have come to be known in the literature as the Frege-Geach Problem, because of Geach's attribution of the objection to Frege's distinction between content and assertoric force, and the problem has since occupied a great deal of the (...) attention both of defenders of broadly noncognitivist views, and of their critics. In this article I explain Geach and Searle's historical objections, and put the subsequent discussion into dialectical context, paying some attention to the developments along the way and how they have enhanced our overall understanding of the problem. The article covers a lot of territory, so we will only be able to see the highlights, along the way. For further reading, see the Works Cited. (shrink)

Expressivism’s central idea is that normative sentences bear the same relation to non-cognitive attitudes that ordinary descriptive sentences bear to beliefs: the expression relation. Allan Gibbard teIls us that “that words express judgments will be accepted by almost everyone” - the distinctive contribution of expressivism, his claim goes, is only a view about what kind of judgments words express. But not every account of the expression relation is equally suitable for the expressivist’s purposes. In fact, what I argue in this (...) paper, considering four possible accounts of expression, is that how suitable each account is for the expressivist’s purpose varies in proportion to how controversial it is. So Gibbard is wrong - if expression is to get expressivism off the ground, then it will be enormously controversial whether words do express judgments. And thus expressivism is committed to strong claims about the semantics of non-normative language. (shrink)

After presenting a simple expressivist account of reports of probabilistic judgements, I explore a classic problem for it, namely the Frege-Geach problem. I argue that it is a problem not just for expressivism but for any reasonable account of ascriptions of graded judgements. I suggest that the problem can be resolved by appropriately modelling imprecise credences.

This essay investigates whether or not we should think that the things we say are identical to the things our sentences mean. It is argued that these theoretical notions should be distinguished, since assertoric content does not respect the compositionality principle. As a paradigmatic example, Kaplan's formal language LD is shown to exemplify a failure of compositionality. It is demonstrated that by respecting the theoretical distinction between the objects of assertion and compositional values certain conflicts between compositionality and contextualism are (...) avoided. This includes the conflict between eternalism and the semantics of tense, the embedding problems for contextualism about epistemic modals and taste claims, and the conflict between direct reference and the semantics of bound pronouns (and monstrous operators). After presenting the theoretical picture which distinguishes assertoric content from compositional semantic value, some objections to the picture are addressed. In so doing, the objection from King (2003) stemming from apparent complications with the interaction of temporal expressions and attitude reports is assessed and shown to be non-threatening. (shrink)

This paper introduces and explores a conservative extension of inquisitive logic. In particular, weak negation is added to the standard propositional language of inquisitive semantics, and it is shown that, although we lose some general semantic properties of the original framework, such an enrichment enables us to model some previously inexpressible speech acts such as weak denial and ‘might’-assertions. As a result, a new modal logic emerges. For this logic, a Fitch-style system of natural deduction is formulated. The main result (...) of this paper is a theorem establishing the completeness of the system with respect to inquisitive semantics with weak negation. At the conclusion of the paper, the possibility of extending the framework to the level of first order logic is briefly discussed. (shrink)

This paper introduces a generalized version of inquisitive semantics, denoted as GIS, and concentrates especially on the role of disjunction in this general framework. Two alternative semantic conditions for disjunction are compared: the first one corresponds to the so-called tensor operator of dependence logic, and the second one is the standard condition for inquisitive disjunction. It is shown that GIS is intimately related to intuitionistic logic and its Kripke semantics. Using this framework, it is shown that the main results concerning (...) inquisitive semantics, especially the axiomatization of inquisitive logic, can be viewed as particular cases of more general phenomena. In this connection, a class of non-standard superintuitionistic logics is introduced and studied. These logics share many interesting features with inquisitive logic, which is the strongest logic of this class. (shrink)

This paper is about the relationship between two questions: the question of what the objects of assertion are and the question of how best to theorise about ‘shifty’ phenomena like modality and tense. I argue that the relationship between these two questions is less direct than is often supposed. I then explore the consequences of this for a number of debates in the philosophy of language.

What does 'might' mean? One hypothesis is that 'It might be raining' is essentially an avowal of ignorance like 'For all I know, it's raining'. But it turns out these two constructions embed in different ways, in particular as parts of larger constructions like Wittgenstein's 'It might be raining and it's not' and Moore's 'It's raining and I don't know it', respectively. A variety of approaches have been developed to account for those differences. All approaches agree that both Moore sentences (...) and Wittgenstein sentences are classically consistent. In this paper I argue against this consensus. I adduce a variety of new data which I argue can best be accounted for if we treat Wittgenstein sentences as being classically inconsistent. This creates a puzzle, since there is decisive reason to think that 'Might p' is classically consistent with 'Not p'. How can it also be that 'Might p and not p' and 'Not p and might p' are classically inconsistent? To make sense of this situation, I propose a new theory of epistemic modals and their interaction with embedding operators. This account makes sense of the subtle embedding behavior of epistemic modals, shedding new light on their meaning and, more broadly, the dynamics of information in natural language. -/- . (shrink)

There are certain uses of and and or that cannot be explained by their normal meanings as truth-functional connectives, even with sophisticated pragmatic resources. These include examples such as The cops show up, and a fight will break out (‘If the cops show up, a fight will break out’), and I have no friends, or I would throw a party (‘I have no friends. If I did have friends, I would throw a party.’). We argue that these uses are indeed (...) distinct from the more ordinary uses of and and or, but that they are nonetheless related in a principled way. To explain them we give an analysis of what we call the dynamic effects of connectives, which arise in all their uses. The special uses at issue are then argued to be instances where the connectives exhibit their dynamic effects without their truth-conditional meaning. (shrink)

It is often assumed that when one party felicitously rejects an assertion made by an- other party, the first party thinks that the proposition asserted by the second is false. This assumption underlies various disagreement arguments used to challenge contex- tualism about some class of expressions. As such, many contextualists have resisted these arguments on the grounds that the disagreements in question may not be over the proposition literally asserted. The result appears to be a dialectical stalemate, with no independent (...) method of determining whether any particular instance of disagreement is over the proposition literally asserted. In this paper, I propose an independent method for assessing whether a disagreement is about what’s literally asserted. Focusing on epistemic modals throughout, I argue that this method provides evidence that some epistemic modal disagreements are in fact not over the proposition literally asserted by the utterance of the epistemic modal sentence. This method provides a way to break the stalemate, and reveals a new data point for theories of epistemic modals to predict—that is, how there can be such modal disagreements. In the rest of the paper, I motivate a general theory of how to predict these kinds of disagreements, and then offer some brief remarks about how contextualist, relativist, and expressivist theories of epistemic modals might accommodate this new data point. (shrink)

Hans Kamp; IV*—Free Choice Permission, Proceedings of the Aristotelian Society, Volume 74, Issue 1, 1 June 1974, Pages 57–74, https://doi.org/10.1093/aristoteli.

We present an inferentialist account of the epistemic modal operator might. Our starting point is the bilateralist programme. A bilateralist explains the operator not in terms of the speech act of rejection ; we explain the operator might in terms of weak assertion, a speech act whose existence we argue for on the basis of linguistic evidence. We show that our account of might provides a solution to certain well-known puzzles about the semantics of modal vocabulary whilst retaining classical logic. (...) This demonstrates that an inferentialist approach to meaning can be successfully extended beyond the core logical constants. (shrink)

We investigate, in a logical setting, the expressivist proposal that assertion primarily functions to express and coordinate doxastic states and that ‘might’ fundamentally expresses lack of belief. We provide a formal model of an agent’s doxastic state and novel assertability conditions for an associated formal language. We thereby prove that an arbitrary assertion always succeeds in expressing a well-defined doxastic state, and propose a fully general and intuitive update operation as a model of an agent coming to accept an arbitrary (...) assertion. Leaving a comprehensive philosophical and linguistic defense for elsewhere, we explore technical aspects of our framework, providing, for instance, a complete logic of assertability and reduction axioms for the novel update operations related to our proposal. Finally, we contrast our work with related proposals in the logic literature. (shrink)

An original and elegant work of metaethics, this book brings a new clarity and rigor to the discussion of these tangled issues, and will significantly alter the ...