Toward a solution to the nesting problem for two-dimensionalism

Activity: Academic talk or presentation typesInvited talk


Post-Kripkean theorising concerning modal epistemology accepts a misalignment between apriority and necessity. Two-dimensional semantics provides a framework in which to analyse the Kripkean phenomena of the contingent a priori and the necessary a posteriori. And, as the name suggests, it does so in terms of two “dimensions” of meaning or two levels of semantic value associated with any linguistic expression. But there is a problem concerning how these two levels compose and interact. In particular the problem concerns nested environments: environments where sentences are nested under both modal and epistemic operators (see Soames 2005, Dever 2007, and Forbes 2011). Soames, in fact, insists that nested environments pose the “chief technical problem” for two-dimensionalism. There is a general problem here for a multi-modal logic with operators for metaphysical necessity and epistemic necessity. In light of the contingent priori we face a dilemma: Either (i) what is a priori is a contingent matter or (ii) it is possible that something is a priori but false. In this talk, I will survey some options for addressing this problem from the perspective of a two-dimensional propositional modal logic with operators both for the modalities of “necessity” and “apriority”. I will demonstrate the undesirable consequences of Chalmers and Rabern’s (2014) semantics for apriority, which appeals to a liveness constraint, and then argue that the alternative proposal of Johannesson and Packalén’s (2016) suffers from a Gettier-style objection. I conclude by exploring a solution which adds a truth predicate to the two-dimensional system.
Period13 Jun 2018
Held atUniversity of Oslo, Norway