Counterpart Theory

Against advanced modalizing

by Josh Parsons

forthcoming in _Defensor Rationis: Essays in honour of Colin Cheyne_, ed. James Maclaurin (2011)

Is everything a world?

by Josh Parsons

Philosophical Studies 134 (2007)

This paper discusses "inclusionism" in the context of David Lewis's modal realism (and in the context of... more This paper discusses "inclusionism" in the context of David Lewis's modal realism (and in the context of parasitic accounts of modality such as John Divers's agnosticism about possible worlds). This is the doctrine that everything is a world. I argue that this doctrine would be beneficial to Divers-style agnosticism; that it suggests a reconfiguration of the concept of actuality in modal realism; and finally that it suffers from an as-yet unsolved difficulty, the problem of the unmarried husbands. This problem also shows that Stephen Yablo's analysis of "intrinsic" is inadequate.

Models for Counterparts

by Alessandro Torza

Torza, A. (2011). Models for Counterparts. Axiomathes, 21(4), 553–579.

David Lewis proposed to test the validity of a modal thesis by checking whether its possible-world translation is a... more David Lewis proposed to test the validity of a modal thesis by checking whether its possible-world translation is a theorem of counterpart theory. However, that criterion fails to validate many standard modal laws, thus raising doubts about the logical adequacy of the Lewisian framework. The present paper considers systems of counterpart theory of increasing strength and shows how each can be motivated by exhibiting a suitable intended model. In particular, perfect counterpart theory validates all the desired modal laws and therefore provides a way out of the logical objection. Finally, a weakening of perfect counterpart theory is put forward as a response to some metaphysical objections.

Keywords: Counterpart theory - Modal logic - Identity - Intended model

'Identity' without Identity

by Alessandro Torza

Forthcoming in Mind (available online).

I introduce and defend the semantic notion of counterfactual identity, distinguishing it from the metaphysical notion... more I introduce and defend the semantic notion of counterfactual identity, distinguishing it from the metaphysical notion of transworld identity. After showing that Lewis’s counterpart theory misconstrues counterfactual identity facts, I outline and motivate a Leibnizian counterpart theory where the notion of counterfactual identity is adequately modeled. Finally, I show that counterfactual identity can be characterized without relying on some implausible features of Lewis’s theory of conditionals.

The semantics of modal predicate logic. part 1: Completeness

by Oliver Kutz