It is argued that the "inner" negation $\mathord{\sim}$ familiar from 3-valued logic can be interpreted as a form of "conditional" negation: $\mathord{\sim}$ is read '$A$ is false if it has a truth value'. It is argued that this reading squares well with a particular 3-valued interpretation of a conditional that in the literature has been seen as a serious candidate for capturing the truth conditions of the natural language indicative conditional (e.g., "If Jim went to the party he had a (...) good time"). It is shown that the logic induced by the semantics shares many familiar properties with classical negation, but is orthogonal to both intuitionistic and classical negation: it differs from both in validating the inference from $A \rightarrow \nega B$ to $\nega(A\rightarrow B)$ to. (shrink)

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

THE INDICATIVE CONDITIONAL. A PROBABILISTIC CRITERION OF SOUNDNESS FOR DEDUCTIVE INFERENCES Our objective in this section is to establish a prima facie case ...

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

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

In classical logic, the proposition expressed by a sentence is construed as a set of possible worlds, capturing the informative content of the sentence. However, sentences in natural language are not only used to provide information, but also to request information. Thus, natural language semantics requires a logical framework whose notion of meaning does not only embody informative content, but also inquisitive content. This paper develops the algebraic foundations for such a framework. We argue that propositions, in order to embody (...) both informative and inquisitive content in a satisfactory way, should be defined as non-empty, downward closed sets of possibilities, where each possibility in turn is a set of possible worlds. We define a natural entailment order over such propositions, capturing when one proposition is at least as informative and inquisitive as another, and we show that this entailment order gives rise to a complete Heyting algebra, with meet, join, and relative pseudo-complement operators. Just as in classical logic, these semantic operators are then associated with the logical constants in a first-order language. We explore the logical properties of the resulting system and discuss its significance for natural language semantics. We show that the system essentially coincides with the simplest and most well-understood existing implementation of inquisitive semantics, and that its treatment of disjunction and existentials also concurs with recent work in alternative semantics. Thus, our algebraic considerations do not lead to a wholly new treatment of the logical constants, but rather provide more solid foundations for some of the existing proposals. (shrink)

In this paper, Carnap's modal logic C is reconstructed. It is shown that the Carnapian approach enables us to create some epistemic logics in a relatively straightforward way. These epistemic modifications of C are axiomatized and one of them is compared with intuitionistic logic. At the end of the paper, some connections between this epistemic logic and Medvedev's logic of finite problems and inquisitive semantics are shortly discussed.

In Context and Content Robert Stalnaker develops a philosophical picture of the nature of speech and thought and the relations between them. Two themes in particular run through these collected essays: the role that the context in which speech takes place plays in accounting for the way language is used to express thought, and the role of the external environment in determining the contents of our thoughts. Stalnaker argues against the widespread assumption of the priority of linguistic over mental representation, (...) which he suggests has had a distorting influence on our understanding. The first part of the book develops a framework for representing contexts and the way they interact with the interpretation of what is said in them. This framework is used to help to explain a range of linguistic phenomena concerning presupposition and assertion, conditional statements, the attribution of beliefs, and the use of names, descriptions, and pronouns to refer. Stalnaker then draws out the conception of thought and its content that is implicit in this framework. He defends externalism about thought--the assumption that our thoughts have the contents they have in virtue of the way we are situated in the world--and explores the role of linguistic action and linguistic structure in determining the contents of our thoughts. Context and Content offers philosophers and cognitive scientists a summation of Stalnaker's important and influential work in this area. His new introduction to the volume gives an overview of this work and offers a convenient way in for those who are new to it. The Oxford Cognitive Science series is a new forum for the best contemporary work in this flourishing field, where various disciplines--cognitive psychology, philosophy, linguistics, cognitive neuroscience, and computational theory--join forces in the investigation of thought, awareness, understanding, and associated workings of the mind. Each book constitutes an original contribution to its subject, but will be accessible beyond the ranks of specialists, so as to reach a broad interdisciplinary readership. The series will be carefully shaped and steered with the aim of representing the most important developments in the field and bringing together its constituent disciplines. (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)