Semantics for Counterpossibles – Yale Weiss

The object of this paper is to examine two approaches for giving non-vacuous truth conditions for counterpossibles, counterfactuals with impossible antecedents. I first develop extensions of a Lewis-style sphere semantics with impossible worlds. I argue that this approach sanctions intuitively invalid inferences and rests on philosophically problematic foundations. I then develop extensions of one of Priest’s ceteris paribus conditional logics with impossible worlds. Certain extensions are shown to have similar problems to the first approach. I suggest reasons for favoring a relatively weak extension of Priest’s logic as a semantics for counterpossibles. Finally, a tableaux proof theory is given for the preferred semantics and soundness and completeness results are sketched.

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Happy New Year! The L&M Workshop will be running again this semester as usual. Mondays 4.15-6.15, CUNY GC. Room still to be fixed. The program as it currently stands is as follows. Details of each meeting will be announced in due course. Note that we will be starting on Feb 27, and May 8 is still to be fixed.  Hope to see you at some of the meetings.  Graham

Feb 27 McCarty UI Bloomington

Mar 6 Kivatinos GC

Mar 13 Picollo Munich

Mar 20 Scambler NYU

Mar 27 Schindler Cambridge

Apr 3 Weiss GC

Apr 10 Spring Recess

Apr 17 Spring Recess

Apr 24 Ciuni Amsterdam

May 1 Malozzi GC

May 8 TBA

May 15 Thomas Ferguson Cycorp