This volume includes a target paper, taking up the challenge to revive, within a modern (formal) framework, a medieval solution to the Liar Paradox which did ...

This chapter focuses on alternative logics. It discusses a hierarchy of logical reform. It presents case studies that illustrate particular aspects of the logical revisionism discussed in the chapter. The first case study is of intuitionistic logic. The second case study turns to quantum logic, a system proposed on empirical grounds as a resolution of the antinomies of quantum mechanics. The third case study is concerned with systems of relevance logic, which have been the subject of an especially detailed reform (...) program. Finally, the fourth case study is paraconsistent logic, perhaps the most controversial of serious proposals. (shrink)

ABSTRACT In ‘The philosophical basis of intuitionistic logic’, Michael Dummett discusses two routes towards accepting intuitionistic rather than classical logic in number theory, one meaning-theoretical and the other ontological. He concludes that the former route is open, but the latter is closed. I reconstruct Dummett's argument against the ontological route and argue that it fails. Call a procedure ‘investigative’ if that in virtue of which a true proposition stating its outcome is true exists prior to the execution of that procedure; (...) and ‘generative’ if the existence of that in virtue of which a true proposition stating its outcome is true is brought about by the execution of that procedure. The problem with Dummett's argument then is that a particular step in it, while correct for investigative procedures, is not correct for generative ones. But it is the latter that the ontological route is concerned with. (shrink)

Brouwer's demonstration of his Bar Theorem gives rise to provocative questions regarding the proper explanation of the logical connectives within intuitionistic and constructivist frameworks, respectively, and, more generally, regarding the role of logic within intuitionism. It is the purpose of the present note to discuss a number of these issues, both from an historical, as well as a systematic point of view.

This book offers an historically-informed critical assessment of Dummett's account of abstract objects, examining in detail some of the Fregean presuppositions whilst also engaging with recent work on the problem of abstract entities.

If proofs are nothing more than truth makers, then there is no force in the standard argument against classical logic (there is no guarantee that there is either a proof forA or a proof fornot A). The standard intuitionistic conception of a mathematical proof is stronger: there are epistemic constraints on proofs. But the idea that proofs must be recognizable as such by us, with our actual capacities, is incompatible with the standard intuitionistic explanations of the meanings of the logical (...) constants. Proofs are to be recognizable in principle, not necessarily in practice, as shown in section 1. Section 2 considers unknowable propositions of the kind involved in Fitch''s paradox:p and it will never be known thatp. It is argued that the intuitionist faces a dilemma: give up strongly entrenched common sense intuitions about such unknowable propositions, or give up verificationism. The third section considers one attempt to save intuitionism while partly giving up verificationism: keep the idea that a proposition is true iff there is a proof (verification) of it, and reject the idea that proofs must be recognizable in principle. It is argued that this move will have the effect that some standard reasons against classical semantics will be effective also against intuitionism. This is the case with Dummett''s meaning theoretical argument. At the same time the basic reason for regarding proofs as more than mere truth makers is lost. (shrink)

A response to a recent critique by Cem Bozşahin of the theory of syntactic semantics as it applies to Helen Keller, and some applications of the theory to the philosophy of computer science.

Two opposed movements of thought threaten philosophy as an autonomous practice from the inside: scientific naturalism and quietism. Naturalism (qua methodological thesis) threatens to turn philosophy into a mere ancilla of the sciences, quietism understood as the prescription to remain silent in philosophy would not countenance any more "positive" philosophy. This book reconstructs naturalism and quietism such that it becomes clear naturalism does have the potential to end philosophy as an autonomous practice and that quietism, correctly understood, does not. To (...) this end, this book provides arguments against the prevailing orthodox status of naturalism and a heterogenous reading of Wittgenstein's metaphilosophical quietism as the rejection of a certain kind of theories in philosophy, namely quasi-scientific theories. (shrink)

It is often thought that endowing a demonstrative with a Fregean sense leaves no room for maintaining that it is also a rigid designator. In addition, some philosophers claim that indexicals - surely the paradigms of singular reference - pose a serious threat to the Fregean sense/ reference approach as they do not comply with the view that singular terms have Fregean senses. In this paper I argue that neither of these is true.

This paper presents a new argument to defend the normativity of meaning, specifically the thesis that there are no meanings without norms. The argument starts from the observation inferentialists have emphasized that incompatibility relations between sentences are a necessary part of meaning as it is understood. We motivate this approach by showing that the standard normativist strategy in the literature, which is developed in terms of veridical reference that may swing free from the speaker’s understanding, violates the ought-implies-can principle, but (...) ours does not. In addition, our approach is superior because, unlike the representationalist approach, it can be extended from declarative sentences to non-representational uses of language. In this paper, however, we only formulate the argument for the base case that involves incompatibility relations between declarative sentences. The goal is not to derive norms from something that is not normative, but to explicate the distinctive type of normativity that is built into meaning as it is understood by language-users. The explication proceeds in two steps. (1) For any sentence s a speaker understands, there is an incompatible sentence s’ the speaker understands to be incompatible with s. (2) In virtue of understanding this incompatibility of meanings, she ought not to be committed to both s and s’. This prohibition is not derived from instrumental practical reason, nor is it based on representational correctness, but its source is the incompatibility of meanings. (shrink)

Until now, antirealists have offered sketches of a theory of truth, at best. In this paper, we present a probabilist account of antirealist truth in some formal detail, and we assess its ability to deal with the problems that are standardly taken to beset antirealism.

This chapter addresses the question of what makes expressions meaningful according to the conception of meaning offered by Donald Davidson. It addresses this question by reflecting on Kathrin Glüer’s recent response to it. It argues that Glüer misconstrues both the evidence for meaning that the radical interpreter must rely on and the way in which the principle of charity must be deployed. The articulation of the correct construal of the evidence and the principle reveals the thoroughly non-reductionist aspect of Davidson’s (...) conception of meaning. This aspect becomes even clearer in his later work, through the articulation of the triangulation argument. I try to show how this argument, which is reconstructed in accordance with Claudine Verheggen’s interpretation of it, helps answer the initial question. The question whether the conception has the resources to account for the objectivity of meaning is briefly discussed. (shrink)

Uno de los principales aportes de Michael Dummett a la filosofía contemporánea fue la idea de que ciertas disputas tradicionales de la metafísica podían ser replanteadas a través de una caracterización semántica del realismo y el antirrealismo. Apoyándose en esta caracterización, Dummett propuso una aproximación ascendente a esas disputas. Dicha aproximación buscaba resolver los desacuerdos metafísicos entre realistas y antirrealistas mediante la formulación de teorías semánticas para ciertos conjuntos de enunciados. En este artículo argumentamos que la caracterización de Dummett no (...) captura las disputas metafísicas tradicionales y que, como consecuencia de ello, dicha caracterización no constituye un buen sustento para la aproximación ascendente. (shrink)

A comprehensive survey of Martin-Löf's constructive type theory, considerable parts of which have only been presented by Martin-Löf in lecture form or as part of conference talks. Sommaruga surveys the prehistory of type theory and its highly complex development through eight different stages from 1970 to 1995. He also provides a systematic presentation of the latest version of the theory, as offered by Martin-Löf at Leiden University in Fall 1993. This presentation gives a fuller and updated account of the system. (...) Earlier, brief presentations took no account of the issues related to the type-theoretical approach to logic and the foundations of mathematics, while here they are accorded an entire part of the book. Readership: Comprehensive accounts of the history and philosophy of constructive type theory and a considerable amount of related material. Readers need a solid background in standard logic and a first, basic acquaintance with type theory. (shrink)

This book brings together philosophers, mathematicians and logicians to penetrate important problems in the philosophy and foundations of mathematics. In philosophy, one has been concerned with the opposition between constructivism and classical mathematics and the different ontological and epistemological views that are reflected in this opposition. The dominant foundational framework for current mathematics is classical logic and set theory with the axiom of choice. This framework is, however, laden with philosophical difficulties. One important alternative foundational programme that is actively pursued (...) today is predicativistic constructivism based on Martin-Löf type theory. Associated philosophical foundations are meaning theories in the tradition of Wittgenstein, Dummett, Prawitz and Martin-Löf. What is the relation between proof-theoretical semantics in the tradition of Gentzen, Prawitz, and Martin-Löf and Wittgensteinian or other accounts of meaning-as-use? What can proof-theoretical analyses tell us about the scope and limits of constructive and predicative mathematics? (shrink)

This volume is about abstract objects and the ways we refer to them in natural language. Asher develops a semantical and metaphysical analysis of these entities in two stages. The first reflects the rich ontology of abstract objects necessitated by the forms of language in which we think and speak. A second level of analysis maps the ontology of natural language metaphysics onto a sparser domain--a more systematic realm of abstract objects that are fully analyzed. This second level reflects the (...) commitments of real metaphysics. The models for these commitments assign truth conditions to natural language discourse. Annotation copyright by Book News, Inc., Portland, OR. (shrink)

The paper enriches the conceptual apparatus of the theory of meaning and denotation that was presented in Part I (Section 3). This part concentrates on the notion of interpretation, which is defined as an equivalence class of the relation possessing the same manner of interpreting types. In this part, some relations between meaning and interpretation, as well as one between denotation an interpretational denotation are established. In the theory of meaning and interpretation, the notion of language communication has been formally (...) introduced and some conditions of correctness of communication have been formulated. (shrink)

Throughout his philosophical career, Michael Dummett held firmly two theses: the theory of meaning has a central position in philosophy and all other forms of philosophical inquiry rest upon semantic analysis, in particular semantic issues replace traditional metaphysical issues; the theory of meaning is a theory of understanding. I will defend neither of them. However, I will argue that there is an important lesson we can learn by reflecting on the link between linguistic competence and semantics, which I take to (...) be an important part of Dummett’s legacy in philosophy of language. I discuss this point in relation to Cappelen and Lepore’s criticism of Incompleteness Arguments. (shrink)

It seems uncontroversial that Dalton wrongly believed that atoms are indivisible. However, the correct analysis of Dalton’s belief and the way it relates to contemporary beliefs about atoms is, on closer inspection, far from straightforward. In this paper, I introduce four features that any candidate analysis is plausibly bound to respect. I argue that theories that individuate concepts at the level of understanding are doomed to fail in this endeavor. I formally sketch an alternative and suggest that cases such as (...) the one presented provide support for the claim that the genuine source for concept individuation is public sharable thought. (shrink)

The meaning of a declarative sentence and that of an interrogative sentence differ in their aspect of mood. A semantics of mood has to account for the differences in meaning between these sentences, and it also has to explain that sentences in different moods may have a common core. The meaning of the declarative mood is to be explained not in terms of actual force (contra Dummett), but in terms of potential force. The meaning of the declarative sentence (including its (...) mood) is called the assertion-candidate, which is explained by what one must know in order to be entitled to utter the declarative with assertive force. Both a cognitive notion (knowledge) and a pragmatic notion (assertive force) are thus part of the explanation of the assertion-candidate. Davidson’s criticism that such a theory is in need of an account of the distinction between standard and non-standard uses of the declarative is answered: without counter-indications an utterance of a declarative sentence is understood as having assertive force. The meaning of an interrogative sentence, the question-candidate, and that of the other sentence types can ultimately be explained in terms of their specific relations to the assertion-candidate. Martin-Löf’s constructive type theory is used to show the philosophical relevance of a semantics of mood. The constructivist notion of proposition needs to be embedded in a theory of the assertion-candidate, which fulfils the offices of being the meaning of the declarative sentence, the content of judgement and assertion and the bearer of epistemic truth. (shrink)

Analytic philosophy has recently been challenged from a perspective advocated by Richard Rorty: this favours edifying philosophy against systematic philosophy comprising also analytic philosophy. In Rorty's presentation analytic philosophy is one more variant of the Cartesian—Kantian epistemology which, being committed to a permanent framework of inquiry rooted in our human subjectivity, implies the uniqueness of one conceptual scheme.Against this tenet I argue in two ways. First, I show that analytic philosophy of mind and language with the Fregean background and possible (...) world semantics implies the pluralism of conceptual schemes on logical-conventionalist grounds. Secondly, I show that although analytic philosophy shares the claim for legitimation of a conceptual scheme with Kantian epistemology, it is critical of the latter in that the uniqueness-claim is refuted. (shrink)

Verificationism has had a bad press for many years. The view that the meaning of our words is bound up with the discernible difference it would make if what we say, think or write were true or false, nowadays is scorned as “positivist” though it was shared by eminent empiricists and pragmatists. This paper seeks to sort through some of the complexities of what is often portrayed as an unduly simplistic conception. I begin with an overview of its main logical (...) empiricist varieties before considering which aspects of it fall victim to which of the three major types of objection that have been raised against it. I will conclude that what is left standing is a modest proposal that seems worth further investigation. (shrink)

We document the influence on programming language semantics of the Platonism/formalism divide in the philosophy of mathematics.

Knowing-how is currently a hot topic in epistemology. But what is the proper subject matter of a study of knowing-how and in what sense can such a study be regarded as epistemological? The aim of this paper is to answer such metaepistemological questions. This paper offers a metaepistemology of knowing-how, including considerations of the subject matter, task, and nature of the epistemology of knowing-how. I will achieve this aim, first, by distinguishing varieties of knowing-how and, second, by introducing and elaborating (...) the concept of hybrid knowing-how, which entails a combination of a ground-level ability and a meta-level perspective on that ability. The stance I wish to advocate is that the epistemology of knowing-how is a normative discipline whose main task is to study the nature and value of human practical intelligence required to do things in a particular manner. (shrink)

One of the main challenges in the philosophy of language is determining the form of knowledge of the rules of language. Michael Dummett has put forth the view that knowledge of the rules of language is a kind of implicit knowledge; some philosophers have mistakenly conceived of this type of knowledge as a kind of knowledge-that . In a recent paper in this journal, Patricia Hanna argues against Dummett’s knowledge-that view and proposes instead a knowledge-how view in which knowledge of (...) the rules of language is a kind of practical knowledge, like an agent’s non-propositional knowledge of counting. In this paper I argue, first, that Hanna misunderstands Dummett’s conception of knowledge of linguistic rules, and, second, that Dummett’s considerations of practical knowledge of language pose a problem for Hanna’s knowledge-how view. At the end of the paper, I briefly sketch an account of practical knowledge of language that meets the requirements set by Dummett. (shrink)

Knowledge of a language is a kind of knowledge, the possession of which enables a speaker to understand and perform a variety of linguistic actions in that language. In this paper, I pursue an agency-oriented approach to knowledge of language. I begin by examining two major agency-oriented models of knowledge of language: Michael Dummett's Implicit Knowledge Model and Jennifer Hornsby's Practical Knowledge Model. I argue that each of these models is inadequate for different reasons. I present an Acquaintance Knowledge Model, (...) in which a speaker's knowledge of a language is a combination of the speaker's first-order linguistic ability and second-order acquaintance with his ability and actions. (shrink)

We present a natural deduction system for dual-intuitionistic logic. Its distinctive feature is that it is a single-premise multiple-conclusions system. Its relationships with the natural deduction systems for intuitionistic and classical logic are discussed.

I argue that thinking of existence questions as deep questions to be resolved by a distinctively philosophical discipline of ontology is misguided. I begin by examining how to understand the truth-conditions of existence claims, by way of understanding the rules of use for ‘exists’ and for general noun terms. This yields a straightforward method for resolving existence questions by a combination of conceptual analysis and empirical enquiry. It also provides a blueprint for arguing against most common proposals for uniform substantive (...) ‘criteria of existence’, whether they involve mind-independence, possession of causal powers, observability, etc., and thus for showing that many arguments for denying entities (numbers, ordinary objects, fictional characters, propositions…) on grounds of their failure to meet one or more of these proposed existence criteria are mistaken. (shrink)

Infectious logics are systems that have a truth-value that is assigned to a compound formula whenever it is assigned to one of its components. This paper studies four-valued infectious logics as the basis of transparent theories of truth. This take is motivated as a way to treat different pathological sentences differently, namely, by allowing some of them to be truth-value gluts and some others to be truth-value gaps and as a way to treat the semantic pathology suffered by at least (...) some of these sentences as infectious. This leads us to consider four distinct four-valued logics: one where truth-value gaps are infectious, but gluts are not; one where truth-value gluts are infectious, but gaps are not; and two logics where both gluts and gaps are infectious, in some sense. Additionally, we focus on the proof theory of these systems, by offering a discussion of two related topics. On the one hand, we prove some limitations regarding the possibility of providing standard Gentzen sequent calculi for these systems, by dualizing and extending some recent results for infectious logics. On the other hand, we provide sound and complete four-sided sequent calculi, arguing that the most important technical and philosophical features taken into account to usually prefer standard calculi are, indeed, enjoyed by the four-sided systems. (shrink)

Wayne Davis’s Meaning, Expression and Thought argues that linguistic meaning is conventional use to express ideas. An obvious problem with this proposal is that complex expressions that have never been used are nonetheless meaningful. In response to this concern, Davis associates conventions of use not only with linguistic expressions but also with the modes in which such expressions can combine into larger expressions. I argue that such constructive conventions are in conflict with the principle of compositionality (as it is usually (...) understood) and that (at least in the cases Davis considers) they are unnecessary for semantic explanations. (shrink)

Inference versus consequence , an invited lecture at the LOGICA 1997 conference at Castle Liblice, was part of a series of articles for which I did research during a Stockholm sabbatical in the autumn of 1995. The article seems to have been fairly effective in getting its point across and addresses a topic highly germane to the Uppsala workshop. Owing to its appearance in the LOGICA Yearbook 1997 , Filosofia Publishers, Prague, 1998, it has been rather inaccessible. Accordingly it is (...) republished here with only bibliographical changes and an afterword. (shrink)

Generalized Quantifier Theory defines superlative quantifiers at most n and at least n as truth-conditionally equivalent to comparative quantifiers fewer than n+1 and more than n \1. It has been demonstrated, however, that this standard theory cannot account for various linguistic differences between these two types of quantifiers. In this paper I discuss how the distinction between assertibility and truth-conditions can be applied to explain this phenomenon. I draw a parallel between the assertibility of disjunctions and superlative quantifiers, and argue (...) that those assertibility conditions are essentially modal. I use epistemic logic to formalize the assertibility conditions and revisit some of the linguistic puzzles related to superlative quantification. (shrink)

This paper examines the prospects for a conceptual or functional role theory of moral concepts. It is argued that such an account is well-placed to explain both the irreducibility and practicality of moral concepts. Several versions of conceptual role semantics for moral concepts are distinguished, depending on whether the concept-constitutive conceptual roles are wide or narrow normative or non-normative and purely doxastic or conative. It is argued that the most plausible version of conceptual role semantics for moral concepts involves only (...) ‘narrow’ conceptual roles, where these include connections to motivational, desire-like, states. In the penultimate section it is argued, contrary to what Wedgwood, Enoch and others have claimed, that such an account of moral concepts cannot plausibly be combined with the claim that moral concepts refer to robust properties. (Published with Open Access.). (shrink)

I address the assumption that communicative interaction is made possible by knowledge of a language. I argue that this assumption as it is usually expressed depends on an unjustified reification of language, and on an unsatisfactory understanding of ‘knowledge’. I propose instead that communicative interaction is made possible by (Rylean) know-how and by the development of (Davidsonian) passing theories. We then come to see that our focus ought to be, not on propositional knowledge of a language which we internally represent, (...) but on the practical application of know-how in our understanding and interpretation of others. (shrink)

An “inferentialist” semantic theory for some language L aims to account for the meanings of the sentences of L solely in terms of the inferential rules governing their use. A “hyper-inferentialist” theory admits into the semantics only “narrowly inferential” rules that normatively relate sentences of L to other sentences of L. A “strong inferentialist” theory also admits into the semantics “broadly inferential” rules that normatively relate perceptual states to sentences of L or sentences of L to intentional actions. It is (...) widely thought that only the latter of these two sorts of semantic theories is at all viable. I argue here that the opposite is so. Negatively, strong inferentialism is viciously circular: including rules into the semantic theory that relate perceptual states to sentences of the language requires us to appeal, in individuating those perceptual states, to the very meanings for which we are supposed to be inferentially accounting. Hyper-inferentialism does not face this problem because it does not appeal to any nonlinguistic states. Positively, though hyper-inferentialism is widely thought to be a theoretical non-starter, I argue here that it is a genuine theoretical possibility insofar as it essentially includes cross-perspectival inferences, inferences along the lines of the one from the sentences “The ball is in front of n,” “The ball is red,” and “The lighting is good” to the sentence “n sees that the ball is red.” I make the further exegetical claim that Robert Brandom, though unanimously taken to be a strong inferentialist, is in fact a hyper-inferentialist. (shrink)

The central premise of Michael Dummett's global argument for anti-realism is the thesis that a speaker's grasp of the meaning of a declarative, indexical-free sentence must be manifested in her uses of that sentence. This enigmatic thesis has been the subject of a great deal of discussion, and something of a consensus has emerged about its content and justification. The received view is that the manifestation thesis expresses a behaviorist and reductive theory of meaning, essentially in agreement with Quine's view (...) of language, and motivated by worries about the epistemology of communication. In the present paper I begin by arguing that this standard interpretation of the manifestation thesis is neither particularly faithful to Dummett's writings nor philosophically compelling. I then continue by reconstructing, from Dummett's texts, an account of the manifestation thesis, and of its justification, that differ sharply from the received view. On my reading, the thesis is motivated not epistemologically, but conceptually. I argue that connections among our conceptions of meaning, assertion, and justification lead to a conclusion about the metaphysics of meaning: we cannot form a clearly coherent conception of how two speakers can attach different meanings to a sentence without at the same time differing in what they count as justifying assertions made with that sentence. I conclude with some suggestions about how Dummett's argument for global anti-realism should be understood, given my account of the manifestation thesis. (shrink)

Whereas there is much discussion about Thomas Kuhn’s notion of methodological incommensurability and many have seen his ideas as an attempt to allow for rational disagreement in science, so far no serious analysis of how exactly Kuhn aims to account for rational disagreement has been proposed. This paper provides the first in-depth analysis of Kuhn’s account of rational disagreement in science—an account that can be seen as the most prominent attempt to allow for rational disagreement in science. Three things will (...) be shown: First, we find not one, but two accounts of rational disagreements in science in Kuhn’s writings: one stemming from methodological incommensurability and one stemming from Kuhn-underdetermination, which are not only fundamentally different—the first purports to explain how disagreeing scientists can nevertheless be rational, while the second attempts to show how rational scientists can nevertheless disagree—but appear to be incompatible with each other. Second, I will assess both accounts. Kuhn’s account from methodological incommensurability is not convincing since it cannot explain rational disagreement in science. Whereas, on the other hand, Kuhn’s account from Kuhn-underdetermination allows for rational disagreement, his argument why we should accept it is not convincing. Third, I present a tentative sketch of an alternative to Kuhn’s account that emphasizes the fallibility of epistemic justification in order to show that Kuhn’s argument founders. In sum, the paper shows that focusing not on the muchly debated consequences of methodological incommensurability, but on Kuhn’s treatment of rational disagreement gives new insight into the adequate interpretation of his thought as well as the cogency of his ideas. (shrink)

I develop a view of the common factor between subjectively indistinguishable perceptions and hallucinations that avoids analyzing experiences as involving awareness relations to abstract entities, sense-data, or any other peculiar entities. The main thesis is that hallucinating subjects employ concepts (or analogous nonconceptual structures), namely the very same concepts that in a subjectively indistinguishable perception are employed as a consequence of being related to external, mind-independent objects or property-instances. These concepts and nonconceptual structures are identified with modes of presentation types. (...) Since a hallucinating subject is not related to any such objects or property-instances, the concepts she employs remain empty. I argue that the phenomenology of hallucinations and perceptions can be identified with employing concepts and analogous nonconceptual structures. By doing so, I defend an ontologically minimalist view of the phenomenology of experience that (1) vindicates Aristotelianism about types and (2) amounts to a naturalized view of the phenomenology of experience. (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)

Taking Per Martin-Löf’s constructive type theory as a starting-point a theory of assertion is developed, which is able to account for the epistemic aspects of the speech act of assertion, and in which it is shown that assertion is not a wide genus. From a constructivist point of view, one is entitled to assert, for example, that a proposition A is true, only if one has constructed a proof object a for A in an act of demonstration. One thereby has (...) grounded the assertion by an act of demonstration, and a grounding account of assertion therefore suits constructive type theory. Because the act of demonstration in which such a proof object is constructed results in knowledge that A is true, the constructivist account of assertion has to ward off some of the criticism directed against knowledge accounts of assertion. It is especially the internal relation between a judgement being grounded and its being known that makes it possible to do so. The grounding account of assertion can be considered as a justification account of assertion, but it also differs from justification accounts recently proposed, namely in the treatment of selfless assertions, that is, assertions which are grounded, but are not accompanied by belief. (shrink)

The paper addresses the situation of a dispute in which one speaker says ϕ and a second speaker says not-ϕ. Proceeding on an idealising distinction between "basic" and "interesting" claims that may be formulated in a given idiolectal language, I investigate how it might be sorted out whether the dispute reflects a genuine disagreement, or whether the speakers are only having a merely verbal dispute, due to their using different interesting concepts. I show that four individually plausible principles for the (...) determination of the nature of a dispute are incompatible. As an example, I discuss the question whether Sarai lied in the story told in Genesis 12. (shrink)