Quineanism, Noneism and Metaphysical Equivalence

In this paper we propose and defend the Synonymy account, a novel account of metaphysical equivalence which draws on the idea (Rayo in The Construction of Logical Space, Oxford University Press, Oxford, 2013) that part of what it is to formulate a theory is to lay down a theoretical hypothesis concerning logical space. Roughly, two theories are synonymous-and so, in our view, equivalent-just in case (i) they take the same propositions to stand in the same entailment relations, and (ii) they are committed to the truth of the same propositions. Furthermore, we put our proposal to work by showing that it affords a better and more nuanced understanding of the debate between Quineans and noneists. Finally we show how the Synonymy account fares better than some of its competitors, specifically, McSweeney's (Philosophical Perspectives 30(1):270-293, 2016) epistemic account and Miller's (Philosophical Quarterly 67(269):772-793, 2017) hyperintensional account.

Automated summary

This paper introduces and defends the Synonymy account, which proposes that two theories are synonymous and equivalent if they have the same propositions and entailment relations, as well as a commitment to the truth of the same propositions. It further demonstrates how this account provides a better understanding of the debate between Quineans and noneists, and compares favorably to other competing accounts.