From belief change to modality : Epistemic semantics for modal and conditional logic
Dahl, Niklas LU
(2026)
In Philosophical Studies
- Abstract
- This paper sets out to extend the epistemic semantics presented in Dahl (2023) to
modal and conditional logics. To do so, I extend the notion of belief expansion sys-
tems, inspired by the AGM-model of belief change, to include belief revision, and
use the resulting structures as models for both conditional and modal logic. In the
first case, this applies the well-known approach to conditionals initiated by Gärden-
fors (1978), but in a weaker setting which doesn’t assume an underlying logic. As
such, we get semantics for both classical conditional logic and the intuitionistic
conditionals studied by Weiss (2019). For modal logics, I use the condition that
φ is accepted if and only if φ is accepted under... (More) - This paper sets out to extend the epistemic semantics presented in Dahl (2023) to
modal and conditional logics. To do so, I extend the notion of belief expansion sys-
tems, inspired by the AGM-model of belief change, to include belief revision, and
use the resulting structures as models for both conditional and modal logic. In the
first case, this applies the well-known approach to conditionals initiated by Gärden-
fors (1978), but in a weaker setting which doesn’t assume an underlying logic. As
such, we get semantics for both classical conditional logic and the intuitionistic
conditionals studied by Weiss (2019). For modal logics, I use the condition that
φ is accepted if and only if φ is accepted under every belief revision. As a result
of this system of semantics, we get soundness and completeness theorems for both
classical and non-classical systems of modal and conditional logic on the basis of
a single type of structure. Finally, I briefly discuss how models based on belief
change can still be thought to explain the semantics of objective modal claims. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/24cdc2ba-a06b-420d-8b8c-764262925f8a
- author
- Dahl, Niklas
LU
- organization
- publishing date
- 2026-05-30
- type
- Contribution to journal
- publication status
- epub
- subject
- keywords
- Belief revision, Modal logic, Conditional logic, Epistemic semantics, Ramsey test
- in
- Philosophical Studies
- pages
- 31 pages
- publisher
- Springer
- external identifiers
-
- scopus:105040525620
- ISSN
- 0031-8116
- DOI
- 10.1007/s11098-025-02459-w
- language
- English
- LU publication?
- yes
- id
- 24cdc2ba-a06b-420d-8b8c-764262925f8a
- date added to LUP
- 2026-05-31 21:10:31
- date last changed
- 2026-06-14 04:01:12
@article{24cdc2ba-a06b-420d-8b8c-764262925f8a,
abstract = {{This paper sets out to extend the epistemic semantics presented in Dahl (2023) to<br/>modal and conditional logics. To do so, I extend the notion of belief expansion sys-<br/>tems, inspired by the AGM-model of belief change, to include belief revision, and<br/>use the resulting structures as models for both conditional and modal logic. In the<br/>first case, this applies the well-known approach to conditionals initiated by Gärden-<br/>fors (1978), but in a weaker setting which doesn’t assume an underlying logic. As<br/>such, we get semantics for both classical conditional logic and the intuitionistic<br/>conditionals studied by Weiss (2019). For modal logics, I use the condition that<br/>φ is accepted if and only if φ is accepted under every belief revision. As a result<br/>of this system of semantics, we get soundness and completeness theorems for both<br/>classical and non-classical systems of modal and conditional logic on the basis of<br/>a single type of structure. Finally, I briefly discuss how models based on belief<br/>change can still be thought to explain the semantics of objective modal claims.}},
author = {{Dahl, Niklas}},
issn = {{0031-8116}},
keywords = {{Belief revision; Modal logic; Conditional logic; Epistemic semantics; Ramsey test}},
language = {{eng}},
month = {{05}},
publisher = {{Springer}},
series = {{Philosophical Studies}},
title = {{From belief change to modality : Epistemic semantics for modal and conditional logic}},
url = {{http://dx.doi.org/10.1007/s11098-025-02459-w}},
doi = {{10.1007/s11098-025-02459-w}},
year = {{2026}},
}