Synthese

, Volume 190, Issue 4, pp 639–660

Remarks on counterpossibles

Article

DOI: 10.1007/s11229-012-0196-6

Cite this article as:
Brogaard, B. & Salerno, J. Synthese (2013) 190: 639. doi:10.1007/s11229-012-0196-6

Abstract

Since the publication of David Lewis’ Counterfactuals, the standard line on subjunctive conditionals with impossible antecedents (or counterpossibles) has been that they are vacuously true. That is, a conditional of the form ‘If p were the case, q would be the case’ is trivially true whenever the antecedent, p, is impossible. The primary justification is that Lewis’ semantics best approximates the English subjunctive conditional, and that a vacuous treatment of counterpossibles is a consequence of that very elegant theory. Another justification derives from the classical lore than if an impossibility were true, then anything goes. In this paper we defend non-vacuism, the view that counterpossibles are sometimes non-vacuously true and sometimes non-vacuously false. We do so while retaining a Lewisian semantics, which is to say, the approach we favor does not require us to abandon classical logic or a similarity semantics. It does however require us to countenance impossible worlds. An impossible worlds treatment of counterpossibles is suggested (but not defended) by Lewis (Counterfactuals. Blackwell, Oxford, 1973), and developed by Nolan (Notre Dame J Formal Logic 38:325–527, 1997), Kment (Mind 115:261–310, 2006a: Philos Perspect 20:237–302, 2006b), and Vander Laan (In: Jackson F, Priest G (eds) Lewisian themes. Oxford University Press, Oxford, 2004). We follow this tradition, and develop an account of comparative similarity for impossible worlds.

Keywords

Impossible worlds Accessibility relation Counterfactuals Subjunctive conditionals Indicative conditionals Lewis semantics Non-trivial counterpossibles Limit assumption Essential properties Contingent counterpossibles 

Copyright information

© Springer Science+Business Media Dordrecht 2012

Authors and Affiliations

  1. 1.Australian National UniversityCanberraAustralia
  2. 2.University of MissouriSt. LouisUSA
  3. 3.St. Louis UniversitySt. LouisUSA

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