Interpersonal independence of knowledge and belief

Lehrer, Ehud; Samet, Dov

Abstract

We show that knowledge satisfies interpersonal independence, meaning that a non-trivial sentence describing one agent’s knowledge cannot be equivalent to a sentence describing another agent’s knowledge. The same property of interpersonal independence holds, mutatis mutandis, for belief. In the case of knowledge, interpersonal independence is implied by the fact that there are no non-trivial sentences that are common knowledge in every model of knowledge. In the case of belief, interpersonal independence follows from a strong interpersonal independence that knowledge does not have. Specifically, there is no sentence describing the beliefs of one person that implies a sentence describing the beliefs of another person.

• Journal Article Type: Article
• Acceptance Date: Apr 25, 2024
• Online Publication Date: Jul 3, 2024
• Publication Date: Jul 3, 2024
• Deposit Date: Apr 12, 2024
• Publicly Available Date: Jul 12, 2024
• Journal: Synthese
• Print ISSN: 0039-7857
• Publisher: Springer
• Peer Reviewed: Peer Reviewed
• DOI: https://doi.org/10.1007/s11229-024-04607-x
• Public URL: https://durham-repository.worktribe.com/output/2381288