The logical omniscience problem, whereby standard models of epistemic logic treat an agent as believing all consequences of its beliefs and knowing whatever follows from what else it knows, has received plenty of attention in the literature. But many attempted solutions focus on a fairly narrow specification of the problem: avoiding the closure of belief or knowledge, rather than showing how the proposed logic is of philosophical interest or of use in computer science or artificial intelligence. Sentential epistemic logics, as (...) opposed to traditional possible worlds approaches, do not suffer from the problems of logical omniscience but are often thought to lack interesting epistemic properties. In this paper, I focus on the case of rule-based agents, which play a key role in contemporary AI research but have been neglected in the logical literature. I develop a framework for modelling monotonic, nonmonotonic and introspective rule-based reasoners which have limited cognitive resources and prove that the resulting models have a number of interesting properties. An axiomatization of the resulting logic is given, together with completeness, decidability and complexity results. (shrink)

It is widely accepted that knowledge of certain of one’s own mental states is authoritative in being epistemically more secure than knowledge of the mental states of others, and theories of self-knowledge have largely appealed to one or the other of two sources to explain this special epistemic status. The first, ‘detectivist’, position, appeals to an inner perception-like basis, whereas the second, ‘constitutivist’, one, appeals to the view that the special security awarded to certain self-knowledge is a conceptual matter. I (...) argue that there is a fundamental class of cases of authoritative self-knowledge, ones in which subjects are consciously thinking about their current, conscious intentional states, that is best accounted for in terms of a theory that is, broadly speaking, introspectionist and detectivist. The position developed has an intuitive plausibility that has inspired many who work in the Cartesian tradition, and the potential to yield a single treatment of the basis of authoritative self-knowledge for both intentional states and sensation states. (shrink)

In this paper, we outline an approach to giving extensional truth-theoretic semantics for what have traditionally been seen as opaque sentential contexts. We outline an approach to providing a compositional truth-theoretic semantics for opaque contexts which does not require quantifying over intensional entities of any kind, and meets standard objections to such accounts. The account we present aims to meet the following desiderata on a semantic theory T for opaque contexts: (D1) T can be formulated in a first-order extensional language; (...) (D2) T does not require quantification over intensional entities­i.e., meanings, propositions, properties, relations, or the like­in its treatment of opaque contexts; (D3) T captures the entailment relations that hold in virtue of form between sentences in the language for which it is a theory; (D4) T has a finite number of axioms. If the approach outlined here is correct, it resolves a longstanding complex of problems in metaphysics, the philosophy of mind and the philosophy of language. (shrink)

Starting with Frege, the semantics (and pragmatics) of quotation has received a steady flow of attention over the last one hundred years. It has not, however, been subject to the same kind of intense debate and scrutiny as, for example, both the semantics of definite descriptions and propositional attitude verbs. Many philosophers probably share Davidson's experience: ‘When I was initiated into the mysteries of logic and semantics, quotation was usually introduced as a somewhat shady device, and the introduction was accompanied (...) by a stern sermon on the sin of confusing the use and mention of expressions’ (Davidson 1979, p. 79). Those who leave it at that, however, miss out on one of the most difficult and interesting topics in the philosophy of language. (shrink)

According to cognitivist truth-theoretic accounts of semantic competence, aspects of our linguistic behavior can be explained by ascribing to speakers cognition of truth theories. It's generally assumed on this approach that, however much context sensitivity speakers' languages contain, the cognized truththeories themselves can be adequately characterized context insensitively—that is, without using in the metalanguage expressions whose semantic value can vary across occasions of utterance. In this paper, I explore some of the motivations for and problems and consequences of dropping this (...) assumption. (shrink)

A semantic theory T for a language L should assign content to utterances of sentences of L. One common assumption is that T will assign p to some S of L just in case in uttering S a speaker A says that p. We will argue that this assumption is mistaken.

Indexical predication is possible as well as the more familiar indexical reference. ‘My curtains are coloured thus’ describes my curtains. The indexical predicate expression it contains stands to possible non‐indexical replacements as a referring indexical does to possible non‐indexical replacements , in that it calls upon the context of utterance to fix its semantic contribution to the whole. Indexical predication is the natural resource to call upon in talk about skilful human performances, where we exhibit considerable know‐how but little explicit (...) know‐that. Speech is among such performances. Both direct and indirect speech reports may be illuminated by seeing them in the light of this thought. A corollary of the approach is that the prospects of providing a formal semantic treatment of indirect speech do not look good. (shrink)

Indexical predication is possible as well as the more familiar indexical reference. ‘My curtains are coloured thus’ describes my curtains. The indexical predicate expression it contains stands to possible non‐indexical replacements as a referring indexical does to possible non‐indexical replacements, in that it calls upon the context of utterance to fix its semantic contribution to the whole. Indexical predication is the natural resource to call upon in talk about skilful human performances, where we exhibit considerable know‐how but little explicit know‐that. (...) Speech is among such performances. Both direct and indirect speech reports may be illuminated by seeing them in the light of this thought. A corollary of the approach is that the prospects of providing a formal semantic treatment of indirect speech do not look good. (shrink)

I have proposed that the complementizerthat has a pragmatic property of demonstrativity, analogous to that ascribed by demonstrative analyses of the semantics of the complementizer but not impinging on the syntactic analysis of sentential embedding. My account explains a number of phenomena, including the illocutionary peculiarities of parentheticals, the pragmatics ofthat-omission, and consequently the distributional statistics ofthat-omission and related grammatical features of embeddings reported in the literature. By this means these phenomena are theoretically unified under a single hypothesis.Furthermore, this demonstrativity (...) is a matter of degree. There is a spectrum of distinct pragmatic manifestations of this demonstrativity, ranging from the purely paratactic-like interpretation that ascribes no illocutionary relation between the speaker and the complement, and is highly incompatible withthat-omission, to the purely parenthetical interpretation where illocutionary force attaches to the complement and is highly conducive tothat-omission.A more general moral appears when the minimally revisionist syntactic consequences of my proposal are compared to the radical syntactic consequences of Thompson and Mulac's. Even if we hold that the syntactic structure of a natural language cannot be grasped outside of its general communicative contexts, we need not connect syntax and pragmatics so immediately as Thompson and Mulac seem to think. By resisting the idea that the syntax of parentheticals isipso facto different from the syntax of compositional embeddings, we allow some “slack” between syntax and pragmatics, thereby enabling us to analyze such subtle syntax-pragmatics interactions as negative-raised parentheticals. The methodological moral is to avoid too facile a connection between syntactic and pragmatic analyses. (shrink)

There are at least four varieties of quotation, including pure, direct, indirect and mixed. A theory of quotation, we argue, should give a unified account of these varieties of quotation. Mixed quotes such as 'Alice said that life is 'difficult to understand'', in which an utterance is directly and indirectly quoted concurrently, is an often overlooked variety of quotation. We show that the leading theories of pure, direct, and indirect quotation are unable to account for mixed quotation and therefore unable (...) to provide a unified theory. In the second half of the paper we develop a unified theory of quotation based on Davidson's demonstrative theory. 'Language is the instrument it is because the same expression, with semantic features (meaning) unchanged, can serve countless purposes.' (Davidson 1968). (shrink)

This chapter argues that while quotation marks are polysemous, the thread that runs through all uses of quotation marks that involve reference to expressions is pure quotation, in which an expression formed by enclosing another expression in quotation marks refers to that enclosed expression. We defend a version of the so-called disquotational theory of pure quotation and show how this device is used in direct discourse and attitude attributions, in exposition in scholarly contexts, and in so-called mixed quotation in indirect (...) discourse and attitude attributions. We argue that uses of quotation marks that extend beyond pure quotation have two features in common. First, the expressions appearing in quotation marks are intended to be understood, and that they are intended to be understood is essential to the function that such quotations play in communication, though this does not always involve the expressions contributing their extensional properties to fixing truth conditions for the sentences in which they appear. Second, they appeal to a relation to the expression appearing in quotation marks that plays a role in determining the truth conditions of the sentences in which they appear. (shrink)

Traditionally, ‘that’-clauses occurring in attitude attributions are taken to denote the objects of the attitudes. Prior raised a famous problem: even if Frege fears that the Begriffsschrift leads to a paradox, it is unlikely that he fears a proposition, a sentence or what have you as the alleged object denoted by the ‘that’-clause. The usual way out is to say that ‘that’-clauses do not contribute the objects of the attitudes but their contents. I will show that, if we accept this (...) answer, either we’d better stop working on attitude attributions or we’d better work harder on them. (shrink)

§§3-4 of the Begriffsschrift present Frege’s objections to a dominant if murky nineteenth-century semantic picture. I sketch a minimalist variant of the pre-Fregean picture which escapes Frege’s criticisms by positing a thin notion of semantic content which then interacts with a multiplicity of kinds of truth to account for phenomena such as modality. After exploring several ways in which we can understand the existence of multiple truth properties, I discuss the roles of pointwise and setwise truth properties in modal logic. (...) I argue that thinking of supertruth and determinate truth as setwise truth properties allows an understanding of supervaluationist approaches to vagueness which escapes both Williamson’s objections to and a needless metalinguistic orientation of traditional supervaluationism. (shrink)

I discuss and defend two arguments against semantic theories which wish to avoid commitment to propositions. The first holds that on the most plausible semantics of a class of natural language sentences, the truth of sentences in that class requires the existence of propositions; and some sentences in that class are true. The second holds that, on the best understanding of the form of a semantic theory, the truth of a semantic theory itself entails the existence of propositions. Much of (...) the discussion engages Davidsonian alternatives to a propositionalist semantic theory. (shrink)

The goal of inquiry in this essay is to ascertain to what extent the Principle of Compositionality – the thesis that the meaning of a complex expression is determined by the meaning of its parts and its mode of composition – can be justifiably imposed as a constraint on semantic theories, and thereby provide information about what meanings are. Apart from the introduction and the concluding chapter the thesis is divided into five chapters addressing different questions pertaining to the overarching (...) goal of inquiry. Chapter Two is an attempt to determine whether the Principle of Compositionality is a trivial principle. It is argued that this is not the case in the context of providing the semantics of natural languages since it is an open question whether the best theories that respect available syntactic and semantic data are compositional. Chapter Three and Chapter Four ask whether there are reasons to think that the Principle of Compositionality is true. It is argued that the three most commonly cited reasons for thinking that correct semantic theories must be compositional – Linguistic Creativity, Productivity and Systematicity – in fact only give us reasons to think that the meaning of complex expressions depend on the meanings of their parts and their modes of composition, but not that the meaning of complex expressions depend ONLY on those factors. Chapter Five asks whether there are any reasons to think that the Principle of Compositionality is false. It is argued that all the phenomena that have been suggested entail non-compositionality are in fact compatible with some versions of compositionality. Even if this conclusion is reached in this chapter, the conclusion of the previous two chapters entails that we are not justified in imposing the Principle of Compositionality as an adequacy constraint on Semantic theories. Chapter Six explores the ways in which information about what meanings are can be derived by imposing constraints on semantic theories. It is argued that the distinction emphasized in Chapter Three and Chapter Four between depending on and depending ONLY on is of critical importance. It is demonstrated that the informative potential of the Principle of Compositionality goes far beyond that of the principle we are in fact justified in imposing on semantic theories. So not only is it the case that we cannot learn anything about meanings from the justified imposition of the Principle of Compositionality – since we cannot justifiably impose it as a constraint on semantic theories – what we could have learned from it had we been justified in imposing it is very different from what we can learn from the principle that we are justified in imposing. (shrink)