Vagueness and intuitionistic logic

Book section : Chapter

This chapter considers the question: should we employ intuitionistic logic, not classical logic, when reasoning with vague concepts? In his commentary on Michael Dummett’s “Wang’s Paradox,” Crispin Wright presents an apparently powerful argument in favour of an affirmative answer to this question. This chapter advocates a less conclusive answer than Wright’s. It is argued that intuitionistic logic may be the strongest logic we are entitled to use in reasoning with any vague predicate, but there may also be common and central families of vague term where we are entitled to use classical logic.

Authors: Rumfitt, I

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Oxford University Press
• Host title: Logic, Language, and Mathematics: Themes from the Philosophy of Crispin Wright
• Pages: 135-152
• Chapter number: 6
• Place of publication: Oxford
• Publication date: 2020-08-20
• DOI: 10.1093/oso/9780199278343.003.0006
• ISBN: 9780199278343
• Language: English
• Keywords: intuitionistic logic; classical logic; Sorites Paradox; vagueness; Dummett
• Subtype: Chapter