The Department of Logic & Philosophy of Science presents
"Actuality and Subjunctivity Workshop"
April 13-14, 2012
9:00 a.m.-5:00 p.m.
Social Sciences Plaza A, Room 2112
After the explosion of technical work in modal logic in the 1960s and the dramatic impact of Kripke's lectures on naming and necessity, logicians realized in the mid-1970s that standard first-order modal languages lacked the resources to express certain modal claims involving essential reference to actual circumstances within the scope of a modal operator, whose formulation in natural languages is effortless. Through the work of Allen Hazen, Lloyd Humberstone, and others, the so-called actuality operator quickly gained acceptance as a fix for this expressive deficit. However, in the early 1980s Humberstone pointed out that these expressive deficits might equally be addressed by means of a subjunctivity operator, in some sense a dual to the actuality operator. Some twenty years later, subjunctivity was independently rediscovered, in the guise of subjunctive markers rather than a sentential operator, by Wehmeier, who had been investigating the stability of some of Kripke's philosophical theses under changes of modal-logical frameworks. Since then, the subjunctivity approach has been extended to cross-world predication and subjunctive conditionals, and applied to the analysis of the knowability paradox. The comparison of the actuality and the subjunctivity approaches has led to intriguing and not yet completely understood philosophical results. The workshop is devoted to new developments in subjunctive modal logic, a deeper understanding of the divide between the two approaches, and issues in philosophy of language and logic arising from the existence of these competing frameworks.