Explanation and Modality: On the Contingency Horn of Blackburn’s Dilemma
Can we explain why some propositions are necessary? Blackburn (Fact, science, and value. Blackwell, Oxford, 1987) has presented a dilemma aimed at showing that the necessity of a proposition cannot be explained either in the case where the explanans is another necessary proposition (necessity horn) or in the case where the explanans is a contingent proposition (contingency horn). Blackburn’s dilemma is intended to show that necessary truth is an explanatorily irreducible kind of truth: there is nothing that explains why propositions are necessary, nothing that makes necessary necessary truths. In this paper, I criticize the contingency horn of Blackburn’s dilemma. On the one hand, I show that the official reconstruction of the horn uses a principle that is incompatible with the notion of explanation plausibly needed to explain why propositions are necessary; on the other, I show that a simpler formulation of the horn, which does not make use of such a controversial principle, makes essential use of principles that are incompatible with the idea that possibilities can have explanatory roles. I then defend the view that possibilities can have explanatory roles, and that the explanatory role of possibilities is best represented, within possible worlds, as the existence of trans-world relations of explanation.
KeywordsHiggs Boson Actual World Contingent Proposition True Proposition Actual Truth
Earlier versions of this paper have been presented at the 6th Latin Meeting in Analytic Philosophy (University of Lisbon) and at the COGITO Seminar (University of Bologna). I would like to thank these two audiences for very stimulating comments and discussions. Special thanks go to Andrea Bianchi, Massimiliano Carrara, Giuseppe Spolaore and two anonymous referees.
- Blackburn, S. (1987). Morals and modals. In C. Wright & C. McDonald, (Eds.), Fact, science, and value. Oxford: Blackwell.Google Scholar
- deRosset, L. (2013). Grounding explanations. Philosopher’s Imprint, 13(7), 1–26.Google Scholar
- Divers, J. (2002). Possible worlds. London: Routledge.Google Scholar
- Hale, B. (2002). The source of necessity. Philosophical Perspectives, 16, 299–319.Google Scholar
- Kripke, S. A. (1963). Semantical considerations on modal logic. Acta Philsophica Fennica, 16, 83–94.Google Scholar
- Lewis, D. K. (1973a). Causation. Journal of Philosophy, 70, 556–567 (Reprinted with a postscript in Lewis (1986, Ch. 21, pp. 159–213)).Google Scholar
- Lewis D. K. (1973b). Counterfactuals. Oxford: Blackwell.Google Scholar
- Lewis D. K. (1986). Philosophical papers (Vol. II). Oxford: Oxford University Press.Google Scholar
- Williamson, T. (2000). Knowledge and its limits. Oxford: Oxford University Press.Google Scholar