Description:

Craig Warmke from Northern Illinois University will be giving a presentation titled, "Deontic Intentionalism".

Abstract: In the language of Standard Deontic Logic, we can say that a proposition φ is obligatory. And in the Logic’s standard semantics, such a statement is true in a world w when φ is true in every possible world “acceptable” to w. Now according to canonical descriptions of the semantics, a world w* is acceptable to a world w when what is obligatory in w is the case in w*. At this point, you might feel that we’ve been given the run-around: ‘it is obligatory that φ’ is true in w when φ is true in every world w* in which what is obligatory in w is the case in w*. Hence, whether a statement about what’s obligatory is true in w depends on what’s true in w-acceptable worlds, but whether a world is w-acceptable depends on what’s obligatory in w. Have we uncovered a vicious circularity?

Some have thought so. This circularity objection deserves our attention because it pinpoints, for the wrong reasons, an otherwise intriguing feature in the semantics. Once we crack open the semantics, we find not circularity but redundancy. It is as if you opened a clock and found that one of the gears was itself a clock. During our time together, I will explain why the semantics for Standard Deontic Logic is not circular but redundant, present a new semantics for Standard Deontic Logic without the redundancy, and conclude with some wide-ranging lessons for modal semantics.