In the Mood for S4: The Expressive Power of the Subjunctive Modal Language in Weak Background Logics
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Our concern here is with the extent to which the expressive equivalence of Wehmeier’s Subjunctive Modal Language (SML) and the Actuality Modal Language (AML) is sensitive to the choice of background modal logic. In particular we will show that, when we are enriching quantified modal logics weaker than S5, AML is strictly expressively stronger than SML, this result following from general considerations regarding the relationship between operators and predicate markers. This would seem to complicate arguments given in favour of SML which rely upon its being expressively equivalent to AML.
KeywordsExpressive power Actuality operator Subjunctive modal logic
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- 1.Armstrong, D., A Combinatorial Theory of Possibility, Cambridge University Press, New York, 1989.Google Scholar
- 3.Chellas, B. F., Modal Logic: An Introduction, Cambridge University Press, Cambridge, 1980.Google Scholar
- 4.French R.: An argument against general validity?. Thought 1, 4–9 (2012)Google Scholar
- 6.Gabbay, D. M., V. Shehtman, and D. Skvortsov, Quantification in Nonclassical Logic Volume 1, Studies in Logic and the Foundations of Mathematics, Elsevier Amsterdam, 2009.Google Scholar
- 17.Wehmeier, K. F., World travelling and mood swings, in B. Löwe, T. Räsch, and W. Malzkorn, (eds.), Foundations of the Formal Sciences II, Kluwer, 2003, pp. 257–260.Google Scholar
- 19.Wehmeier, K. F., Modality, mood, and descriptions, in R. Kahle, (ed.), Intensionality—an Interdisciplinary Discussion, AK Peters, Wellesley, Mass., 2005, pp. 187–216.Google Scholar
- 21.Wehmeier K. F.: Subjunctivity and conditionals. The Journal of Philosophy 110, 117–142 (2013)Google Scholar