This collection of papers, celebrating the contributions of Swedish logician Dag Prawitz to Proof Theory, has been assembled from those presented at the Natural Deduction conference organized in Rio de Janeiro to honour his seminal research. Dag Prawitz’s work forms the basis of intuitionistic type theory and his inversion principle constitutes the foundation of most modern accounts of proof-theoretic semantics in Logic, Linguistics and Theoretical Computer Science. The range of contributions includes material on the extension of natural deduction with higher-order (...) rules, as opposed to higher-order connectives, and a paper discussing the application of natural deduction rules to dealing with equality in predicate calculus. The volume continues with a key chapter summarizing work on the extension of the Curry-Howard isomorphism, via methods of category theory that have been successfully applied to linear logic, as well as many other contributions from highly regarded authorities. With an illustrious group of contributors addressing a wealth of topics and applications, this volume is a valuable addition to the libraries of academics in the multiple disciplines whose development has been given added scope by the methodologies supplied by natural deduction. The volume is representative of the rich and varied directions that Prawitz work has inspired in the area of natural deduction. (shrink)

This volume examines the concept of falsification as a central notion of semantic theories and its effects on logical laws. The point of departure is the general constructivist line of argument that Michael Dummett has offered over the last decades. From there, the author examines the ways in which falsifications can enter into a constructivist semantics, displays the full spectrum of options, and discusses the logical systems most suitable to each one of them. While the idea of introducing falsifications into (...) the semantic account is Dummett's own, the many ways in which falsificationism departs quite radically from verificationism are here spelled out in detail for the first time. The volume is divided into three large parts. The first part provides important background information about Dummett’s program, intuitionism and logics with gaps and gluts. The second part is devoted to the introduction of falsifications into the constructive account and shows that there is more than one way in which one can do this. The third part details the logical effects of these various moves. In the end, the book shows that the constructive path may branch in different directions: towards intuitionistic logic, dual intuitionistic logic and several variations of Nelson logics. The author argues that, on balance, the latter are the more promising routes to take. "Kapsner’s book is the first detailed investigation of how to incorporate the notion of falsification into formal logic. This is a fascinating logico-philosophical investigation, which will interest non-classical logicians of all stripes." Graham Priest, Graduate Center, City University of New York and University of Melbourne. (shrink)

The volume includes twenty-five research papers presented as gifts to John L. Bell to celebrate his 60th birthday by colleagues, former students, friends and admirers. Like Bell’s own work, the contributions cross boundaries into several inter-related fields. The contributions are new work by highly respected figures, several of whom are among the key figures in their fields. Some examples: in foundations of maths and logic ; analytical philosophy, philosophy of science, philosophy of mathematics and decision theory and foundations of economics. (...) Most articles are contributions to current philosophical debates, but contributions also include some new mathematical results, important historical surveys, and a translation by Wilfrid Hodges of a key work of arabic logic. (shrink)

This monograph proposes a new way of studying the different forms of correlational inference, known in the Islamic jurisprudence as qiyās. According to the authors’ view, qiyās represents an innovative and sophisticated form of dialectical reasoning that not only provides new epistemological insights into legal argumentation in general but also furnishes a fine-grained pattern for parallel reasoning which can be deployed in a wide range of problem-solving contexts and does not seem to reduce to the standard forms of analogical reasoning (...) studied in contemporary philosophy of science and argumentation theory. After an overview of the emergence of qiyās and of the work of al-Shīrāzī penned by Soufi Youcef, the authors discuss al-Shīrāzī’s classification of correlational inferences of the occasioning factor. The second part of the volume deliberates on the system of correlational inferences by indication and resemblance. The third part develops the main theoretical background of the authors’ work, namely, the dialogical approach to Martin-Löf's Constructive Type Theory. The authors present this in a general form and independently of adaptations deployed in parts I and II. Part III also includes an appendix on the relevant notions of Constructive Type Theory, which has been extracted from an overview written by Ansten Klev. The book concludes with some brief remarks on contemporary approaches to analogy in Common and Civil Law and also to parallel reasoning in general. (shrink)

Communication and content presents a comprehensive and foundational account of meaning based on new versions of situation theory and game theory. The literal and implied meanings of an utterance are derived from first principles assuming little more than the partial rationality of interacting agents. New analyses of a number of diverse phenomena – a wide notion of ambiguity and content encompassing phonetics, syntax, semantics, pragmatics, and beyond, vagueness, convention and conventional meaning, indeterminacy, universality, the role of truth in communication, semantic (...) change, translation, Frege’s puzzle of informative identities – are developed. Communication, speaker meaning, and reference are defined. Frege’s context and compositional principles are generalized and reconciled in a fixed-point principle, and a detailed critique of Grice, several aspects of Lewis, and some aspects of the Romantic conception of meaning are offered. Connections with other branches of linguistics, especially psycholinguistics, sociolinguistics, historical linguistics, and natural language processing, are explored. -/- The book will be of interest to scholars in philosophy, linguistics, artificial intelligence, and cognitive science. It should also interest readers in related fields like literary and cultural theory and the social sciences. (shrink)

The Manifestation Requirement, advanced by Dummett in his critique of semantic realism, has been criticized for being behavioristic, and the responses have been made that the critics are mistaken. However, the dispute has failed to exhibit the point of the Requirement. In this paper, I shall argue (1) that, in the light of Anscombe's theory of practical knowledge, knowledge of linguistic meaning is to be seen as the knowledge-how that forms the basis of the practical knowledge that an agent has (...) of his own intentional actions, (2) that such knowledge of linguistic meaning is to be based on mutual agreements in a community, and (3) that the Manifestation Requirement is a condition for the possibility of such mutual agreements. As a result, the Manifestation Requirement finds its basis on the idea that language and linguistic acts are tools that we use while continually improving them. (shrink)

This volume is dedicated to Prof. Dag Prawitz and his outstanding contributions to philosophical and mathematical logic. Prawitz's eminent contributions to structural proof theory, or general proof theory, as he calls it, and inference-based meaning theories have been extremely influential in the development of modern proof theory and anti-realistic semantics. In particular, Prawitz is the main author on natural deduction in addition to Gerhard Gentzen, who defined natural deduction in his PhD thesis published in 1934. The book opens with an (...) introductory paper that surveys Prawitz's numerous contributions to proof theory and proof-theoretic semantics and puts his work into a somewhat broader perspective, both historically and systematically. Chapters include either in-depth studies of certain aspects of Dag Prawitz's work or address open research problems that are concerned with core issues in structural proof theory and range from philosophical essays to papers of a mathematical nature. Investigations into the necessity of thought and the theory of grounds and computational justifications as well as an examination of Prawitz's conception of the validity of inferences in the light of three “dogmas of proof-theoretic semantics” are included. More formal papers deal with the constructive behaviour of fragments of classical logic and fragments of the modal logic S4 among other topics. In addition, there are chapters about inversion principles, normalization of proofs, and the notion of proof-theoretic harmony and other areas of a more mathematical persuasion. Dag Prawitz also writes a chapter in which he explains his current views on the epistemic dimension of proofs and addresses the question why some inferences succeed in conferring evidence on their conclusions when applied to premises for which one already possesses evidence. (shrink)

This volume is the first ever collection devoted to the field of proof-theoretic semantics. Contributions address topics including the systematics of introduction and elimination rules and proofs of normalization, the categorial characterization of deductions, the relation between Heyting's and Gentzen's approaches to meaning, knowability paradoxes, proof-theoretic foundations of set theory, Dummett's justification of logical laws, Kreisel's theory of constructions, paradoxical reasoning, and the defence of model theory. The field of proof-theoretic semantics has existed for almost 50 years, but the term (...) itself was proposed by Schroeder-Heister in the 1980s. Proof-theoretic semantics explains the meaning of linguistic expressions in general and of logical constants in particular in terms of the notion of proof. This volume emerges from presentations at the Second International Conference on Proof-Theoretic Semantics in Tübingen in 2013, where contributing authors were asked to provide a self-contained description and analysis of a significant research question in this area. The contributions are representative of the field and should be of interest to logicians, philosophers, and mathematicians alike. (shrink)

In this work, it is shown that given a correct understanding of the nature of reference and of linguistic meaning generally, it is possible to produce non-revisionist analyses of the nature of -/- *Perceptual content, *Mental content generally, *Logical equivalence, *Logical dependence generally, *Counterfactual truth, *The causal efficacy of mental states, and *Our knowledge of ourselves and of the external world. -/- In addition, set-theoretic interpretations of several semantic concepts are put forth. These concepts include truth, falsehood, negation, and conjunction.

Inference is a process by which appropriate belief states get connected. Belief states are biological states in the sense that they are reentrant loops ; their intrinsic feature is recognition. In inference or reasoning the transition process between belief states is regulated by the rule of concept usage, involved in the belief state, in natural language. Like belief states experiential states are also biological states whose extrinsic feature is recognition, such that, one can have an, say, X-type experience without recognizing (...) it as an experience of X. One can, however, also have an experience of an X; in the latter case, one not only has an X-type experience but also recognizes an X as an X. In some cases the transition from X-type experience to believing an X to be there instantiates a quasi-inferential pattern. In all such cases the transition process is regulated by the rule of X usage. In such quasi-inferential transition additional belief states are involved. Such states assert that there are no countervailing factors and there are additional factors conducive to the conclusion. Such belief states are expressed non-propositionally in the language of thought. Propositions are a necessary part of such quasi-inference for they give content to thoughts to which one can assign 'falsity' and defeasible reasoning requires us to assign 'falsity' to our thoughts. Propositions implicated in the quasi-inferences from experience types to belief states are the evidential reasons for the conclusion and they can only be accepted as provisionally true and have to be revised in the light of further information. (shrink)

This book combines insights from philosophy and linguistics to develop a novel framework for theorizing about linguistic meaning and the role of context in interpretation. A key innovation is to introduce explicit representations of context — assignment variables — in the syntax and semantics of natural language. The proposed theory systematizes a spectrum of “shifting” phenomena in which the context relevant for interpreting certain expressions depends on features of the linguistic environment. Central applications include local and nonlocal contextual dependencies with (...) quantifiers, attitude ascriptions, conditionals, questions, and relativization. The result is an innovative, philosophically informed compositional semantics compatible with the truth-conditional paradigm. (shrink)

In this autobiographical sketch, which is followed by a bibliography of my writings, I try to relate my intellectual development to problems, ideas and results in proof-theoretic semantics on which I have worked and to which I have contributed.

In a recent paper, Peacocke (2001) continues an ongoing debate with McDowell and others, providing renewed arguments for the view that perceptual experiences and some other mental states have a particular kind of content, nonconceptual content. In this article I want to object to one of the arguments he provides. This is not because I side with McDowell in the ongoing debate about nonconceptual content; on the contrary, given the way I understand it, my views are closer to Peacocke’s, and (...) have been strongly influenced by him. It is just that I am not persuaded by the particular argument I will be questioning here. (shrink)

This book describes a novel conception of reality, one that uniquely incorporates an idealistic view of existence with an account of objectivity. It introduces a general model of conceptual analysis and demonstrates its effectiveness in exposing and establishing the existence of conceptual ties. The book begins by introducing the tools and principles needed for the conceptual analysis undertaken in chapters that follow. Next, it presents a detailed examination into existence, contingency, idealism, self-consciousness and natural laws. In the process, the author (...) critically examines the conceptions of existence held by Kant, Frege and Russell; argues that the determinations of past, present and future are subjective in the sense that they imply the existence of consciousness in relation to which they are fixed; shows that every possible reality includes sufficient conditions for self-consciousness; and confronts the question of the "uniformity of nature," which states that reality is subject to natural laws. In the end, the idealistic conception of reality developed in this book implies that existence is relative, rather than absolute, in the sense that it is determined in relation to a point of view internal to reality. This view of existence implies that reality necessarily exists. (shrink)

Descartes famously argued, on purely conceptual grounds, that even an extremely powerful being could not trick him into mistakenly judging that he was thinking. Of course, it is not necessarily true that Descartes is thinking. Still, Descartes claimed, it is necessarily true that if a person judges that she is thinking, that person is thinking. Following Tyler Burge (1988) we call such judgments ‘self-verifying.’ More exactly, a judgment j performed by a subject S at a time t is selfverifying if (...) and only if the fact that S has made j at t entails that j is true at t.2 Burge follows Descartes in claiming that the category of conceptually self-verifying judgments includes (but is not restricted to) judgments that give rise to sincere assertions of sentences of the form, ‘I am thinking that p’. We call such judgments ‘cogito’ judgments. In this paper I argue that Burge’s Cartesian insight is hard to reconcile with Fregean accounts of the content of thought. Theorists have tried to account for the self-verifying status of cogito judgments by arguing that the second-order judgment that one is thinking that p contains the thought that p as a part of it. I argue (§1) that the accuracy of the containment model is entailed by a Russellian view of content (according to which ‘‘belief’’ contexts are both extensional and transparent) when the Russellian view is attached to some fairly uncontroversial assumptions. The accuracy of the containment model is also entailed by non-hierarchical Fregean views of content according to which expressions in oblique contexts both denote and express first-level senses (§2), but there are compelling arguments against non-hierarchical Fregean views (§3). Moreover, the extremely plausible account of self-verification provided by Russellianism is not entailed by theories that follow Frege in accepting a hierarchy of senses and so allow that expressions in oblique contexts express senses that are not identical to the senses they there denote (§4).. (shrink)

Burge follows Descartes in claiming that the category of conceptually self-verifying judgments includes (but is not restricted to) judgments that give rise to sincere assertions of sentences of the form, 'I am thinking that p'. In this paper I argue that Burge’s Cartesian insight is hard to reconcile with Fregean accounts of the content of thought. Burge's intuitively compelling claim that cogito judgments are conceptually self-verifying poses a real challenge to neo-Fregean theories of content.

Numerous authors have attempted to carve an ontological distinction between events and processes on the basis of a widely noted linguistic datum involving count and mass nouns, where events are thought to be analogous to countable objects while processes to non-countable stuff. By assessing the most developed of these proposals—that of Helen Steward’s—this paper locates the motivations behind the project of carving some such distinction between events and processes, and proceeds to offer considerations toward an alternative account of processes—one whose (...) ontology is more akin to that of states than it is to stuff. (shrink)

Recent Neo-Davidsonian accounts of the semantics of progressive constructions of action verbs reflect an ontological distinction between processes or incomplete events on the one hand, and complete events on the other. This paper has two goals. First, it attempts to show that this putative ontological distinction is beset with problems. The second goal of this paper is to offer the beginnings of a positive proposal that seeks to show how the ontologically austere Davidsonian can account for the truth conditions of (...) progressive constructions without the need for an enriched ontology. (shrink)

According to a certain conception of language, any sentence can, when used on an occasion, have any of indefinitely many truth-conditions. Such a conception of language gives us reason to think that the question of whether the notion of truth has a distinctive content cannot be settled by looking solely at the predication of truth. By focusing on the predicate ‘true’ when trying to determine the significance of the notion of truth, we may have been looking in the wrong place.

A widely held view about Fregean Sense has it that the determination of a sign's referent by the sign's sense is achieved viasatisfaction: the sense specifies a condition (or set of conditions) and the referent is that entity, if any, which uniquely satisfies that (set of) condition(s). This is usually held in conjunction with the claim that the sense is existentially and qualitatively independent of the referent: if the referent did not exist, or did not uniquely satisfy the sense, the (...) sense would still exist and would still specify the same condition(s) that it actually does (and might determine a different referent than its actual one). Proponents of this view give several reasons for holding it. I describe these reasons and argue that they are not convincing. More generally, I try to show that the notion of satisfaction has no useful application within Frege's system. I then suggest an alternative account of the determination of a referent by a sense that I think is truer to Frege and more illuminating. Compared to the satisfaction view, my account construes determination as a more naturalistic and epistemically real relation between speakers and things in the world. (shrink)

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)

Abstract: This article considers the conceptual connections between self-consciousness, objectivity, and time. The model of conceptual analysis employed examines the necessary conditions of the meaningfulness of expressions in language. In the course of this analysis two distinct options for the explanation of self-consciousness are identified and examined. According to the first (Strawsonian) view, self-consciousness is based upon the distinction between the self and other subjects of consciousness; according to the second (Kantian) view, self-consciousness is based upon the distinction between the (...) self and the world. The first option is rejected, and a variation of the second option is adopted. According to it, in self-consciousness one is conscious of oneself as a temporally extended point of view (consciousness) over an objective and temporal realm of reality. (shrink)

In Grundgesetze der Arithmetik, Frege tried to show that arithmetic is logical by giving gap-free proofs from what he took to be purely logical basic laws. But how do we come to judge these laws as true, and to recognize them as logical? The answer must involve giving an account of the apparent arguments Frege provides for his axioms. Following Sanford Shieh, I take these apparent arguments to instead be exhibitions: the exercise of a logical capacity in order to bring (...) us into a state of judgement. I provide an account of what sort of inferential capacities are at play in such exhibitions, and explain how they lead us to judge that Frege’s primitive laws are general and undeniable. I will also situate my account with respect to other rival interpretations, particularly the elucidatory interpretations of Joan Weiner and Thomas Ricketts. (shrink)

As Quine observed, the following sentence has a reading which, if true, would be of special interest to the authorities: Ralph believes that someone is a spy. This is the reading where the quantifier is naturally understood as taking wide scope relative to the attitude verb and as binding a variable within the scope of the attitude verb. This essay is interested in addressing the question what the semantic analysis of this kind of reading should look like from a Fregean (...) perspective—a perspective according to which attitude states are generally relations to structured Fregean thoughts composed of senses. The Fregean view faces a challenge of compositionality here. This essay describes the challenge and offers a response on the Fregean's behalf. (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.

This comment focuses on Chapter 9 of The Boundary Stones of Thought and the argument, due to William Tait, that Ian Rumfitt there sustains for the indeterminacy of set. I argue that Michael Dummett’s argument, based on the notion of indefinite extensibility and set aside by Rumfitt, provides a more powerful basis for the same conclusion. In addition, I outline two difficulties for the way Rumfitt attempts to save classical logic from acknowledged failures of the principle of bivalence, one specifically (...) for his treatment of the set-theoretic case, the other of more general bearing but especially germane to the case of vagueness. (shrink)

This paper examines the potential for abstracting propositions – an as yet untested way of defending the realist thesis that propositions as abstract entities exist. I motivate why we should want to abstract propositions and make clear, by basing an account on the neo-Fregean programme in arithmetic, what ontological and epistemological advantages a realist can gain from this. I then raise a series of problems for the abstraction that ultimately have serious repercussions for realism about propositions in general. I first (...) identify problems about the number of entities able to be abstracted using these techniques. I then focus on how issues of language relativity result in problems akin to the Caesar problem in arithmetic by exposing circularity and modal concern over the status of the criterion of identity for propositions. (shrink)

It is widely accepted by formal and informal logicians alike that a formal logic which, by the lights of English, gets the connectives wrong, nevertheless conspires to get entailment right—right that is, modulo English. There is a vexing problem occasioned by this semantic alienation of formal logic. It is next to impossible for formal logic to meet the expectations of realism. What, then, of informal logic?

This paper argues that the principle of necessary identity (f)(g)(f=g then necessarily f=g) cannot be maintained, At least in second order form. A paradox based upon scientific definitional practice is introduced to demonstrate this. A non-Fregean reading of standard contingent identity semantics is provided to explain how such 'definition breaking' works.

This book on infinite regress arguments provides (i) an up-to-date overview of the literature on the topic, (ii) ready-to-use insights for all domains of philosophy, and (iii) two case studies to illustrate these insights in some detail. Infinite regress arguments play an important role in all domains of philosophy. There are infinite regresses of reasons, obligations, rules, and disputes, and all are supposed to have their own moral. Yet most of them are involved in controversy. Hence the question is: what (...) exactly is an infinite regress argument, and when is such an argument a good one? (shrink)

In a recent paper, after outlining various distinguishing features of derogatory words, Jennifer Hornsby suggests that the phenomenon raises serious difficulties for inferentialism. Against Hornsby, I claim that derogatory words do not pose any insuperable problems for inferentialism, so long as it is supplemented with apparatus borrowed from Grice and Hare. Moreover, I argue, derogatory expressions pose difficulties for Hornsby's favoured alternative theory of meaning, representationalism, unless it too is conjoined with a similar Grice/Hare mechanism. So, the upshot of the (...) discussion is that, contra Hornsby, focus on derogatory expressions alone does not provide grounds for deciding between competing theories of meaning, but nevertheless serves to highlight important features that any such theory must acknowledge and incorporate. (shrink)

According to inferential role semantics, for any given expression to possess a particular meaning one must be disposed to make or, alternatively, acknowledge as correct certain inferential transitions involving it. As Williamson points out, pejoratives such as ‘Boche’ seem to provide a counter-example to IRS. Many speakers are neither disposed to use such expressions nor consider it proper to do so. But it does not follow, as IRS appears to entail, that such speakers do not understand pejoratives or that they (...) lack meaning. In this paper, I examine recent responses to this problem by Boghossian and Brandom and argue that their proposed construal of the kind of inferential rules governing a pejorative such as ‘Boche’ is to be ruled out on the grounds that it is non-conservative. I defend the appeal to conservatism in this instance against criticism and, in doing so, propose an alternative approach to pejoratives on behalf of IRS that resolves the problem Williamson poses. (shrink)

The doctrine that meanings are entitieswith a determinate and independent reality is often believed tohave been undermined by Quine's thought experiment of radicaltranslation, which results in an argument for the indeterminacy oftranslation. This paper argues to the contrary. Starting fromQuine's assumption that the meanings of observation sentences arestimulus meanings, i.e., set-theoretical constructions of neuronalstates uniquely determined by inter-subjectively observable facts,the paper shows that this meaning assignment, up to isomorphism,is uniquely extendable to all expressions that occur inobservation sentences. To do so, (...) a theorem recently proven byHodges is used. To derive the conclusion, one only has to assumethat languages are compositional, abide by a generalized contextprinciple and by what I call the category principle. Theseassumptions originating in Frege and Husserl are coherent withQuine's overall position. It is concluded that Quine'snaturalistic approach does not justify scepticism with regard tomeaning, but should rather result in a view that affiliatessemantics with neuroscience. (shrink)

In §93 of The Principles of Mathematics, Bertrand Russell observes that “the variable is a very complicated logical entity, by no means easy to analyze correctly”. This assessment is borne out by the fact that even now we have no fully satisfactory understanding of the role of variables in a compositional semantics for first-order logic. In standard Tarskian semantics, variables are treated as meaning-bearing entities; moreover, they serve as the basic building blocks of all meanings, which are constructed out of (...) variable assignments. But this has disquieting consequences, including Fine’s antinomy of the variable and an undue dependence of meanings on language. Here I develop an alternative, Fregean version of predicate logic that uses the traditional quantifier–variable apparatus for the expression of generality, possesses a fully compositional, non-representational semantics, and is not subject to the antinomy of the variable. The advantages of Fregean over Tarskian predicate logic are due to the former’s treating variables not as meaningful lexical items, but as mere marks of punctuation, similar to parentheses. I submit that this is indeed how the variables of predicate logic should be construed. (shrink)

The purpose of the present paper is to challenge some received assumptions about the logical analysis of modal English, and to show that these assumptions are crucial to certain debates in current philosophy of language. Specifically, I will argue that the standard analysis in terms of quantified modal logic mistakenly fudges important grammatical distinctions, and that the validity of Kripke's modal argument against description theories of proper names crucially depends on ensuing equivocations.

This paper provides a new argument for a position of Crispin Wright's: given that ethical statements can be embedded within all sorts of sentential operators and are subject to definite standards of warrantedness, they must have truth conditions. Allan Gibbard's normative logic' is the only noncognitivist logic that stands a chance of avoiding Geach's Fregean objection. But what, according to Gibbard, is the point of avoiding inconsistency in one's ethical statements? He must say that it is to ensure that one's (...) ethical statements have a property that has certain features. But the only property that has those features is truth. (shrink)

Tim Crane's The Objects of Thought is, I think, a much needed corrective to standard ways that analytic philosophers think about nonexistence. It starts from our common sense thought and talk, and tries to carve out a position that can defend this starting point in the face of criticism. It is well-written, a pleasure to read, and largely clear. I would recommend it to anyone interested in the problems of nonexistence. In §1 I sketch Crane's central ideas about the nonexistent, (...) before turning to themes that I would like to have heard more about. In §2, I distinguish two problems of nonexistence, showing that whilst Crane solves one, he does not address the other. Although Crane did not seek to address both problems, I think we should recognize that there is this residual problem of nonexistence remaining. Next (§3), I argue that whilst Crane is correct to think that a negative free logic has to be rejected if we construe it as making a claim about grammatical subject-predicate sentences, we might be able to salvage it if we recognise a class of logical predicates. But whether this is possible or not, depends on the solution to the unaddressed problem of nonexistence. In the final two sections I briefly raise a concern about Crane's view of quantification, before making a suggestion about his view might be employed in addressing Geach's problem of intentional identity. (shrink)

This paper sets out a predicative response to the Russell-Myhill paradox of propositions within the framework of Church’s intensional logic. A predicative response places restrictions on the full comprehension schema, which asserts that every formula determines a higher-order entity. In addition to motivating the restriction on the comprehension schema from intuitions about the stability of reference, this paper contains a consistency proof for the predicative response to the Russell-Myhill paradox. The models used to establish this consistency also model other axioms (...) of Church’s intensional logic that have been criticized by Parsons and Klement: this, it turns out, is due to resources which also permit an interpretation of a fragment of Gallin’s intensional logic. Finally, the relation between the predicative response to the Russell-Myhill paradox of propositions and the Russell paradox of sets is discussed, and it is shown that the predicative conception of set induced by this predicative intensional logic allows one to respond to the Wehmeier problem of many non-extensions. (shrink)

Imperatives cannot be true or false, so they are shunned by logicians. And yet imperatives can be combined by logical connectives: "kiss me and hug me" is the conjunction of "kiss me" with "hug me". This example may suggest that declarative and imperative logic are isomorphic: just as the conjunction of two declaratives is true exactly if both conjuncts are true, the conjunction of two imperatives is satisfied exactly if both conjuncts are satisfied—what more is there to say? Much more, (...) I argue. "If you love me, kiss me", a conditional imperative, mixes a declarative antecedent ("you love me") with an imperative consequent ("kiss me"); it is satisfied if you love and kiss me, violated if you love but don't kiss me, and avoided if you don't love me. So we need a logic of three -valued imperatives which mixes declaratives with imperatives. I develop such a logic. (shrink)

Apparently, aiming to comply with the norm ‘Believe that P if and only if the proposition that P is true’ can hardly differ from aiming to comply with the norm ‘Believe that P if and only if the proposition that P is epistemically justified’. So one may be tempted to agree with Richard Rorty that the distinction between truth and justification is pragmatically useless because it cannot make any difference ‘when the question is about what I should believe now’. I (...) resist this conclusion by arguing that the distinction between truth and justification is pragmatically useful even if the two properties are indeed normatively coincident. The argument I offer turns on the claim that truth plays an explanatory role that justification is inherently incapable of playing. However, my contention is not just that the distinction between truth and justification is pragmatically useful because truth is a bona fide explanatory notion. It is that the distinction between truth and justification is pragmatically useful because the realization that the former plays an explanatory role that the latter is inherently incapable of playing gives access to reasons which would otherwise escape our attention. If truth is a bona fide explanatory notion, the distinction between truth and justification is pragmatically useful because it is precisely when the question is about what I should believe now that attending to such a distinction will often make a difference – and it will make a difference even if the two properties are in fact normatively coincident. (shrink)

There are two interpretations of what it means for a singular term to be referentially direct, one truth-conditional and the other cognitive. It has been argued that on the former interpretation, both proper names and indexicals refer directly, whereas on the latter only proper names are directly referential. However, these interpretations in fact apply to the same singular terms. This paper argues that, if conceived in purely normative terms, the linguistic meaning of indexicals can no longer be held to make (...) these terms referentially indirect under the second interpretation. This result is then generalized to proper names, by ascribing them a normative meaning as well. (shrink)

One of the characteristic features of contemporary logic is that it incorporates the Frege‐Russell thesis according to which verbs for being are multiply ambiguous. This thesis was not accepted before the nineteenth century. In Aristotle existence could not serve alone as a predicate term. However, it could be a part of the force of the predicate term, depending on the context. For Kant existence could not even be a part of the force of the predicate term. Hence, after Kant, existence (...) was left homeless. It found a home in the algebra of logic in which the operators corresponding to universal and particular judgments were treated as duals, and universal judgments were taken to be relative to some universe of discourse. Because of the duality, existential quantifier expressions came to express existence. The orphaned notion of existence thus found a new home in the existential quantifier. (shrink)