Structural Modality as the Criterion for Naturalistic Involvement in Scientific Metaphysics

Ladyman & Berenstain 2012 argue that Ontic Structural Realism (OSR) attributes rich natural necessities to the world whereas Epistemic Structural Realism (ESR) developed by Worrall 1989 and Constructive Empiricism do not. Although it is undoubtedly clear that the world is intrinsically de-modalized according to Constructive Empiricism, I think there is a place for natural necessities in ESR since the negative argument about our epistemic access to the basic furniture of the world and attributing structural natural necessities to it can be held at the same time. The reason for that is an argument due to Stanford (Stanford et al. 2010). He has shown that modality claims in OSR do not say anything more than endorsing No Miracle Argument (NMA). Since ESR, just like OSR, endorses NMA, modality can similarly be attributed to structures in ESR; hence modality cannot be introduced as a distinctive feature for OSR. After showing that introducing modality supports OSR and ESR equally, I will try to understand the significance of natural necessities in a plausible version of naturalized metaphysics that would be suitable for structuralism. I will argue, following Wilson (forthcoming), that modality is the key component of naturalistic involvement. Since natural necessities have the same strength in OSR and ESR, I will conclude that naturalized metaphysics developed by Ladyman & Ross could easily be adapted for ESR. Although I endorse Wilson’s argument that modality should be taken as the criteria for naturalisticness, I reject his claim that his position provides the strongest version of scientific modality since it reconciles Lewisian modal realism with Everettian quantum mechanics. For, post-positivist concept analysis driven analytic metaphysics mainly populated with Lewis is the primary target for most scientific metaphysicians today; hence combining modal realism with current fundamental physics would not strike most of the naturalized metaphysicians as a successful reconciliation. I conclude by arguing that an account for structural modalities, including structural necessities in ESR, is the most convenient locus for a plausible version of naturalized metaphysics.