Arche - the AHRB Centre for the Philosophy of Logic, Language,
Mathematics, and Mind - is pleased to announce our second Modality
Workshop, to be held on the 14th and 15th of May, 2004.
The second modality workshop took place on the 14th and 15th of May 2004. In vited speakers were John Hawthorne (Rutgers), Joseph Melia (Leeds), Ian Rumfitt (Oxford), and L.A. Paul (Arizona).
Hawthorne spoke on the relationship between David Chalmers's "two dimensionalism" and Cartesian rationalism. Both Chalmers and Descartes claim to be able to refute physicalism on apriori grounds. In both cases there is an inference from conceivability to possibility. This type of inference is part of an attractive epistemology of modality, but there are well known apparent counterexamples (most famously those discussed by Kripke). Chalmers's work tackles these counterexamples; Hawthorne argued that he does so unsuccessfully.
Melia defended a form of modalism that drew on recent work in truthmaker theory. Typically modalists suffer from a lack of expressive power relative to possible worlds semanticists, as the latter can employ explicit quantification over possible worlds and possible individuals. One tactic for modalists to employ (developed by Graeme Forbes) involves enhancing the syntax of modal operators to make them as expressive as explicit possibilist quantifiers. The cost of this is that it is hard to see how to interpret these new resources except as an implicit way of quantifying over possible individuals. Melia's modalism attempted to use no resources other than the box and diamond of classical quantified modal logic.
Rumfitt explored ways of extending quantified modal logic to include plural quantifiers. This would allow us to express some modal statements of natural language that do not seem to be expressible in ordinary QML. However, for plural quantifiers to solve that problem we would need plurals to rigid, in the sense that a plurality should "contain the same things" in each possible world in which those things exist. Rumfitt's formulation required a distinct axiom to ensure this, and he discussed the question of whether that axiom amounted to a kind of essentialism.
Paul applied the idea of multiple realisability to individuals (instead of, as it is usually applied, to states - e.g. mental states). The aim was to give an account of constitution (for example, of the relationship between persons and bodies) that is not the familiar "identity" account. The drawback of the identity theory is that persons and bodies appear to have different modal properties (I could be disembodied, but my body could not be disembodied). Paul approach gave a novel solution to this problem.
The workshop attracted a number of participants from outside St. Andrews, including Scott Shalkowski (Leeds), and John Divers (Sheffield).
-- JoshParsons - 15 Mar 2004