In Groenendijk & Stokhof [1989] a system of dynamic predicate logic (DPL) was developed, as a compositional alternative for classical discourse representation theory (DRT ). DPL shares with DRT the restriction of being a first-order system. In the present paper, we are mainly concerned with overcoming this limitation. We shall define a dynamic semantics for a typed language with λ-abstraction which is compatible with the semantics DPL specifies for the language of first-order predicate logic. We shall propose to use this (...) new logical system as the semantic component of a Montague-style grammar (referred to as dynamic Montague grammar, DMG), which will enable us to extend the compositionality of DPL to the subsentential level. Furthermore, we shall extend this analysis also in this sense that we shall add new, dynamic interpretations for logical constants which in DPL were treated in a static fashion. This will substantially increase the descriptive coverage of DMG. (shrink)

Of course, although this view on meaning was the prevailing one for almost a century, many of the people who initiated the enterprise of logical semantics, including people like Frege and Wittgenstein, had an open eye for all that it did not catch. However, the logical means which Frege, Wittgenstein, Russell, and the generation that succeeded them, had at their disposal were those of classical mathematical logic and set-theory, and these indeed are not very suited for an analysis of other (...) aspects of meaning than those which the slogan covers. A real change in view then had to await the emergence of other concepts, which in due course became available mainly under the influence of developments in computer science and cognate disciplines such as artificial intelligence. And this is one of the reasons why it took almost a century before any serious and successful challenge of the view that meaning equals truthconditions from within logical semantics could emerge. (shrink)

way on the information available in the contexts in which they are used, it’s not surprising that there is a minor but growing industry of work in semantics and the philosophy of language concerned with the precise nature of the context-dependency of epistemically modalized sentences. Take, for instance, an epistemic might-claim like..

On the basis of arguments showing that none of the most influential analyses of Moore’s paradox yields a successful resolution of the problem, a new analysis of it is offered. It is argued that, in attempting to render verdicts of either inconsistency or self-contradiction or self-refutation, those analyses have all failed to satisfactorily explain why a Moore-paradoxical proposition is such that it cannot be rationally believed. According to the proposed solution put forward here, a Moore-paradoxical proposition is one for which (...) the believer can have no non-overridden evidence. The arguments for this claim make use of some of Peter Klein’s views on epistemic defeasibility. It is further suggested that this proposal may have important meta-epistemological implications. (shrink)

On the basis of arguments showing that none of the most influential analyses of Moore's paradox yields a successful resolution of the problem, a new analysis of it is offered. It is argued that, in attempting to render verdicts of either inconsistency or self‐contradiction or self‐refutation, those analyses have all failed to satisfactorily explain why a Moore‐paradoxical proposition is such that it cannot be rationally believed. According to the proposed solution put forward here, a Moore‐paradoxical proposition is one for which (...) the believer can have no non‐overridden evidence. the arguments for this claim make use of some of Peter Klein's views on epistemic defeasibility. It is further suggested that this proposal may have important meta‐epistemological implications. (shrink)

On the basis of arguments showing that none of the most influential analyses of Moore's paradox yields a successful resolution of the problem, a new analysis of it is offered. It is argued that, in attempting to render verdicts of either inconsistency or self‐contradiction or self‐refutation, those analyses have all failed to satisfactorily explain why a Moore‐paradoxical proposition is such that it cannot be rationally believed. According to the proposed solution put forward here, a Moore‐paradoxical proposition is one for which (...) the believer can have no non‐overridden evidence. the arguments for this claim make use of some of Peter Klein's views on epistemic defeasibility. It is further suggested that this proposal may have important meta‐epistemological implications. (shrink)

According to a popular closure principle for epistemic justification, if one is justified in believing each of the premises in set Φ and one comes to believe that ψ on the basis of competently deducing ψ from Φ—while retaining justified beliefs in the premises—then one is justified in believing that ψ. This principle is prima facie compelling; it seems to capture the sense in which competent deduction is an epistemically secure means to extend belief. However, even the single-premise version of (...) this closure principle is in conflict with certain seemingly good inferences involving the epistemic possibility modal ♢. According to other compelling principles concerning competent deduction and epistemic justification, one can competently infer ¬♢φ from ¬φ in deliberation even though there are cases in which one can justifiably believe ¬φ but would be unjustified in believing ¬♢φ. Thus, as we argue, philosophers must choose between unrestricted closure for justification and the validity of these other principles. (shrink)

When is a belief or judgment justified? One might be forgiven for thinking the search for single answer to this question to be hopeless. The concept of justification is required to fulfil several tasks: to evaluate beliefs epistemically, to fill in the gap between truth and knowledge, to describe the virtuous organization of one’s beliefs, to describe the relationship between evidence and theory (and thus relate to confirmation and probabilification). While some of these may be held to overlap, the prospects (...) for fulfilling all may well seem poor. Furthermore the internalist requires that justification be an introspectible property of beliefs and a fundamental epistemic concept, while the externalist is often happy to ignore the concept altogether or at best regard it as an embarrassing add-on to their epistemology. In the light of this one might reasonably give up on justification altogether or adopt pluralist approach, denying that justification is any single property of beliefs of judgments. (shrink)

David Lewis (1941-2001) was Class of 1943 University Professor of Philosophy at Princeton University. His contributions spanned philosophical logic, philosophy of language, philosophy of mind, philosophy of science, metaphysics, and epistemology. In On the Plurality of Worlds, he defended his challenging metaphysical position, "modal realism." He was also the author of the books Convention, Counterfactuals, Parts of Classes, and several volumes of collected papers.

By means of an example, shows the possibility of beliefs that are separately rational whilst together inconsistent.

We investigate a basic probabilistic dynamic semantics for a fragment containing conditionals, probability operators, modals, and attitude verbs, with the aim of shedding light on the prospects for adding probabilistic structure to models of the conversational common ground.

This paper defends a counterexample to Modus Tollens, and uses it to draw some conclusions about the logic and semantics of indicative conditionals and probability operators in natural language. Along the way we investigate some of the interactions of these expressions with 'knows', and we call into question the thesis that all knowledge ascriptions have truth-conditions.

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.

Many epistemologists call themselves ‘fallibilists’. But many philosophers of language hold that the meaning of epistemic usages of ‘possible’ ensures a close knowledge- possibility link : a subject’s utterance of ‘it’s possible that not-p’ is true only if the subject does not know that p. This seems to suggest that whatever the core insight behind fallibilism is, it can’t be that a subject could have knowledge which is, for them, possibly false. I argue that, on the contrary, subjects can have (...) such possibly false knowledge. My ultimate aim, then, is to vindicate a very robust form of fallibilism. Uniquely, however, the account I offer does this while also allowing that concessive knowledge attributions – sentences of the form “I know that p, but it’s possible that not-p” – are not only infelicitous but actually false whenever uttered. The account predicts this result without conceding KPL. I argue that my account has the resources to explain some related cases for which the KPL account yields the wrong predictions. Taken as a whole, the linguistic data not only do not support the proposal that subjects cannot have possibly false knowledge, but indeed positively favor the proposal that they can. (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)

I consider the problem of how to derive what an agent believes from their credence function and utility function. I argue the best solution of this problem is pragmatic, i.e. it is sensitive to the kinds of choices actually facing the agent. I further argue that this explains why our notion of justified belief appears to be pragmatic, as is argued e.g. by Fantl and McGrath. The notion of epistemic justification is not really a pragmatic notion, but it is being (...) applied to a pragmatically defined concept, i.e. belief. (shrink)

It is a recurring mantra that epistemic must creates a statement that is weaker than the corresponding flat-footed assertion: It must be raining vs. It’s raining. Contrary to classic discussions of the phenomenon such as by Karttunen, Kratzer, and Veltman, we argue that instead of having a weak semantics, must presupposes the presence of an indirect inference or deduction rather than of a direct observation. This is independent of the strength of the claim being made. Epistemic must is therefore quite (...) similar to evidential markers of indirect evidence known from languages with rich evidential systems. We work towards a formalization of the evidential component, relying on a structured model of information states (analogous to some models used in the belief dynamics literature). We explain why in many contexts, one can perceive a lack of confidence on the part of the speaker who uses must. (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.

I will be arguing that a subject’s belief that p is justified if and only if he knows that p: justification is knowledge. I will start by describing two broad classes of allegedly justified beliefs that do not constitute knowledge and which, hence, cannot be what they are often taken to be if my view is correct. It is far from clear what my view is until I say a lot more about the relevant concept or concepts of justification that (...) concern me. The following section describes several concepts of justification that epistemologists have employed, and, in particular, identifies the two concepts of justification that I claim are coextensive with the concept of knowledge. One of those is the deontological conception of justification: I will be arguing that one ought not believe that p unless one knows that p. I imagine that the major opposition to my view will be that it is simply obvious that there are justified false beliefs, a feeling that I try to dispel in the lengthy section on concepts of justification before I finally get around to giving the main arguments in favor of my view. A view as unorthodox as mine demands more than a single argument: I offer four in the third section. Everyone allows that many people have many unjustified beliefs, and everyone has some unjustified beliefs, but such beliefs appear to be far more prevalent on my view than on more orthodox views. In the last section, I argue that unjustified beliefs, although widespread, are not quite as common as they might appear to be on my view. (shrink)

Predicates of personal taste (fun, tasty) and epistemic modals (might, must) share a similar analytical difficulty in determining whose taste or knowledge is being expressed. Accordingly, they have parallel behavior in attitude reports and in a certain kind of disagreement. On the other hand, they differ in how freely they can be linked to a contextually salient individual, with epistemic modals being much more restricted in this respect. I propose an account of both classes using Lasersohn’s (Linguistics and Philosophy 28: (...) 643–686, 2005) “judge” parameter, at the same time arguing for crucial changes to Lasersohn’s view in order to allow the extension to epistemic modals and address empirical problems faced by his account. (shrink)

This paper is a companion piece to my earlier paper “Fallibilism and Concessive Knowledge Attributions”. There are two intuitive charges against fallibilism. One is that it countenances the truth (and presumably acceptability) of utterances of sentences such as “I know that Bush is a Republican, though it might be that he is not a Republican”. The second is that it countenances the truth (and presumably acceptability) of utterances of sentences such as “I know that Bush is a Republican, even though (...) I’m not certain that he is”, or “I know that Bush it a Republican, even though it isn’t certain that he is.” In “Fallibilism and Concessive Knowledge Attributions”, I argue that fallibilism in epistemology does not countenance the truth of utterances of sentences such as “I know that Bush is a Republican, though it might be that he is not a Republican”. In this paper, I argue that there are independent reasons for thinking that utterances of sentences such as “I know that Bush is a Republican, though I’m not certain that he is” and “I know that Bush is a Republican, though it’s not certain that he is” are unassertible. More specifically, I argue that these are simply instances of Moore’s Paradox, such as “Dogs bark, but I don’t know that they do.” The right account of Moore’s Paradox does not involve the falsehood of the semantic content of the relevant utterances, but rather their pragmatic unacceptability. So the anti-fallibilist intuitions turn out to have pragmatic, rather than semantic import, and therefore do not tell against the truth of fallibilism. Fallibilism in epistemology is often thought to be theoretically desirable, but intuitively problematic. My purpose with these two papers is to show that fallibilism is not intuitively problematic. (shrink)

Lewis concludes that fallibilism is uncomfortable, though preferable to scepticism. However, he believes that contextualism about knowledge allows us to ‘dodge the choice’ between fallibilism and scepticism. For the contextualist semantics for ‘know’ can explain the oddity of fallibilism, without landing us into scepticism.

In ‘Epistemic Modals’ (2007), Seth Yalcin proposes Stalnaker-style semantics for epistemic possibility. He is inspired by John MacFarlane’s ingenious defence of relativism, in which claims of epistemic possibility are made rigidly from the perspective of the assessor’s actual stock of information (rather than from the speaker’s knowledge base or that of his audience or community). The innovations of MacFarlane and Yalcin independently reinforce the modal collapse espoused by Jaakko Hintikka in his 1962 epistemic logic (which relied on the implausible KK (...) principle and heavy idealizations). I respond to this new challenge with fresh objections to the underlying S4 equivalence: p p . I also propose counter-analyses of the intriguing data which Yalcin cites in support of his new semantics. A key collateral motivation for this defence of irredundant iterations is to ward off a threat to higher order vagueness. (shrink)

Closure for justification is the claim that thinkers are justified in believing the logical consequences of their justified beliefs, at least when those consequences are competently deduced. Many have found this principle to be very plausible. Even more attractive is the special case of Closure known as Single-Premise Closure. In this paper, I present a challenge to Single-Premise Closure. The challenge is based on the phenomenon of rational self-doubt – it can be rational to be less than fully confident in (...) one's beliefs and patterns of reasoning. In rough outline, the argument is as follows: Consider a thinker who deduces a conclusion from a justified initial premise via an incredibly long sequence of small competent deductions. Surely, such a thinker should suspect that he has made a mistake somewhere. And surely, given this, he should not believe the conclusion of the deduction even though he has a justified belief in the initial premise. (shrink)

Recently, Yalcin (Epistemic modals. Mind, 116 , 983–1026, 2007) put forward a novel account of epistemic modals. It is based on the observation that sentences of the form ‘ & Might ’ do not embed under ‘suppose’ and ‘if’. Yalcin concludes that such sentences must be contradictory and develops a notion of informational consequence which validates this idea. I will show that informational consequence is inadequate as an account of the logic of epistemic modals: it cannot deal with reasoning from (...) uncertain premises. Finally, I offer an alternative way of explaining the relevant linguistic data. (shrink)

This essay develops a joint theory of rational (all-or-nothing) belief and degrees of belief. The theory is based on three assumptions: the logical closure of rational belief; the axioms of probability for rational degrees of belief; and the so-called Lockean thesis, in which the concepts of rational belief and rational degree of belief figure simultaneously. In spite of what is commonly believed, this essay will show that this combination of principles is satisfiable (and indeed nontrivially so) and that the principles (...) are jointly satisfied if and only if rational belief is equivalent to the assignment of a stably high rational degree of belief. Although the logical closure of belief and the Lockean thesis are attractive postulates in themselves, initially this may seem like a formal “curiosity”; however, as will be argued in the rest of the essay, a very reasonable theory of rational belief can be built around these principles that is not ad hoc and that has various philosophical features that are plausible independently. In particular, this essay shows that the theory allows for a solution to the Lottery Paradox, and it has nice applications to formal epistemology. The price that is to be paid for this theory is a strong dependency of belief on the context, where a context involves both the agent's degree of belief function and the partitioning or individuation of the underlying possibilities. But as this essay argues, that price seems to be affordable. (shrink)

Is it possible to give an explicit definition of belief in terms of subjective probability, such that believed propositions are guaranteed to have a sufficiently high probability, and yet it is neither the case that belief is stripped of any of its usual logical properties, nor is it the case that believed propositions are bound to have probability 1? We prove the answer is ‘yes’, and that given some plausible logical postulates on belief that involve a contextual “cautiousness” threshold, there (...) is but one way of determining the extension of the concept of belief that does the job. The qualitative concept of belief is not to be eliminated from scientific or philosophical discourse, rather, by reducing qualitative belief to assignments of resiliently high degrees of belief and a “cautiousness” threshold, qualitative and quantitative belief turn out to be governed by one unified theory that offers the prospects of a huge range of applications. Within that theory, logic and probability theory are not opposed to each other but go hand in hand. (shrink)

It is a truism that people speak ‘loosely’——that is, that they often say things that we can recognize not to be true, but which come close enough to the truth for practical purposes. Certain expressions. such as those including ‘exactly’, ‘all’ and ‘perfectly’, appear to serve as signals of the intended degree of approximation to the truth. This article presents a novel formalism for representing the notion of approximation to the truth, and analyzes the meanings of these expressions in terms (...) of this formalism. Pragmatic loosencss of this kind should be distinguished from authentic truth-conditional vagueness. (shrink)

This paper investigates the way that linguistic expressions influence vagueness, focusing on the interpretation of the positive (unmarked) form of gradable adjectives. I begin by developing a semantic analysis of the positive form of ‘relative’ gradable adjectives, expanding on previous proposals by further motivating a semantic basis for vagueness and by precisely identifying and characterizing the division of labor between the compositional and contextual aspects of its interpretation. I then introduce a challenge to the analysis from the class of ‘absolute’ (...) gradable adjectives: adjectives that are demonstrably gradable, but which have positive forms that relate objects to maximal or minimal degrees, and do not give rise to vagueness. I argue that the truth conditional difference between relative and absolute adjectives in the positive form stems from the interaction of lexical semantic properties of gradable adjectives—the structure of the scales they use—and a general constraint on interpretive economy that requires truth conditions to be computed on the basis of conventional meaning to the extent possible, allowing for context dependent truth conditions only as a last resort. (shrink)