Lewis, the lottery and the preface

Abstract

Context-dependence is commonly believed to be a widespread phenomenon in natural language. In a context where the standards of precision are very demanding (say, a rocket launch), an utterance of ‘It’s 3 pm’ said at 3.01 will be reckoned false. Reduce the standards of precision and an utterance of the same sentence at the same time will be reckoned true. Semanticists habitually accommodate phenomena of this type by allowing that utterances of the same sentence type express different propositions on different occasions of use, owing to variations along contextual parameters that are not explicitly marked in the surface structure of the sentence itself. Contextualists in epistemology hold that the verb ‘know’ provides yet another case of context-dependence, expressing diverse relations on different occasions of use owing to shifting standards for its application. In Lewis’s particular version of contextualism, the key contextual parameter is the divide between the possible worlds that are being properly ignored by the ascriber and those that are not. He offers the following definition: