, Volume 79, Issue 2, pp 327–349 | Cite as

Explanation and Modality: On the Contingency Horn of Blackburn’s Dilemma

  • Vittorio Morato
Original Article


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.


Higgs Boson Actual World Contingent Proposition True Proposition Actual Truth 
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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.


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Copyright information

© Springer Science+Business Media Dordrecht 2013

Authors and Affiliations

  1. 1.Department of PhilosophyUniversity of PaduaPaduaItaly

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