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)

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..

A very simple contextualist treatment of a sentence containing an epistemic modal, e.g. a might be F, is that it is true iff for all the contextually salient community knows, a is F. It is widely agreed that the simple theory will not work in some cases, but the counterexamples produced so far seem amenable to a more complicated contextualist theory. We argue, however, that no contextualist theory can capture the evaluations speakers naturally make of sentences containing epistemic modals. If (...) we want to respect these evaluations, our best option is a relativist theory of epistemic modals. On a relativist theory, an utterance of a might be F can be true relative to one context of evaluation and false relative to another. We argue that such a theory does better than any rival approach at capturing all the behaviour of epistemic modals. (shrink)

Recently, von Fintel (2001) and Gillies (2007) have argued that certain sequences of counterfactuals, namely reverse Sobel sequences, should motivate us to abandon standard truth conditional theories of counterfactuals for dynamic semantic theories. I argue that we can give a pragmatic account of our judgments about counterfactuals without giving up the standard semantics. In particular, I introduce a pragmatic principle governing assertability, and I use this principle to explain a variety of subtle data concerning reverse Sobel sequences.

By “epistemic modals,” I mean epistemic uses of modal words: adverbs like “necessarily,” “possibly,” and “probably,” adjectives like “necessary,” “possible,” and “probable,” and auxiliaries like “might,” “may,” “must,” and “could.” It is hard to say exactly what makes a word modal, or what makes a use of a modal epistemic, without begging the questions that will be our concern below, but some examples should get the idea across. If I say “Goldbach’s conjecture might be true, and it might be false,” (...) I am not endorsing the Cartesian view that God could have made the truths of arithmetic come out differently. I make the claim not because I believe in the metaphysical contingency of mathematics, but because I know that Goldbach’s conjecture has not yet been proved or refuted. Similarly, if I say “Joe can’t be running,” I am not saying that Joe’s constitution prohibits him from running, or that Joe is essentially a non-runner, or that Joe isn’t allowed to run. My basis for making the claim may be nothing more than that I see Joe’s running shoes hanging on a hook. (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.

The goal of this paper is to make sense of relativism about truth. There are two key ideas. (1) To be a relativist about truth is to allow that a sentence or proposition might be assessment-sensitive: that is, its truth value might vary with the context of assessment as well as the context of use. (2) Making sense of relativism is a matter of understanding what it would be to commit oneself to the truth of an assessment-sensitive sentence or proposition.

I think that there are good reasons to adopt a relativist semantics for epistemic modal claims such as ``the treasure might be under the palm tree'', according to which such utterances determine a truth value relative to something finer-grained than just a world (or a <world, time> pair). Anyone who is inclined to relativise truth to more than just worlds and times faces a problem about assertion. It's easy to be puzzled about just what purpose would be served by assertions (...) of this kind, and how to understand what we'd be up to in our use of sentences like ``the treasure might be under the palm tree'', if they have such peculiar truth conditions. After providing a very quick argument to motivate a relativist view of epistemic modals, I bring out and attempt to resolve this problem in making sense of the role of assertions with relativist truth conditions. Solving this problem should be helpful in two ways: first, it eliminates an apparently forceful objection to relativism, and second, spelling out the relativist account of assertion and communication will help to make clear just what the relativist position is, exactly, and why it's interesting. (shrink)

First published in 2002. Routledge is an imprint of Taylor & Francis, an informa company.

Hans Kamp; IV*—Free Choice Permission, Proceedings of the Aristotelian Society, Volume 74, Issue 1, 1 June 1974, Pages 57–74, https://doi.org/10.1093/aristoteli.

Eleven distinguished philosophers have contributed specially written essays on a set of topics much debated in recent years, including physicalism, qualia, semantic competence, conditionals, presuppositions, two-dimensional semantics, and the relation between logic and metaphysics. All these topics are prominent in the work of Robert Stalnaker, a major presence in contemporary philosophy, in honor of whom the volume is published. It also contains a substantial new essay in which Stalnaker replies to his critics, and sets out his current views on the (...) topics discussed. (shrink)

This paper will be concerned with the conjunctive interpretation of a family of disjunctive constructions. The relevant conjunctive interpretation, sometimes referred to as a “free choice effect,” (FC) is attested when a disjunctive sentence is embedded under an existential modal operator. I will provide evidence that the relevant generalization extends (with some caveats) to all constructions in which a disjunctive sentence appears under the scope of an existential quantifier, as well as to seemingly unrelated constructions in which conjunction appears under (...) the scope of negation and a universal quantifier. (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.

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.

The book generalises earlier theories of belief change to cover all kinds of changes of sets by sets. The principal focus is still on changes of belief sets in response to new evidence, but the formal theory extends to all domains with a closure operation and a preference structure including, for example, systems of action. Contraction is the key notion; all other changes can be defined. Various new applications of the theory are outlined. A sentential version of contraction, subtraction, is (...) proposed as a formal counterpart to 'except'-locutions in natural language. Connections are emphasised with other areas at the interface between philosophical logic and artificial intelligence such as reasoning from default assumptions or from inconsistent premises. A relation of merge inference is proposed as a means of retrieving maximal but nontrivial information from inconsistent premises. Merge inference respects certain anti-Boolean intuitions while avoiding a revision of classical logic. (shrink)