, Volume 191, Issue 6, pp 1037–1050 | Cite as

Information closure and the sceptical objection

  • Luciano Floridi


In this article, I define and then defend the principle of information closure (pic) against a sceptical objection similar to the one discussed by Dretske in relation to the principle of epistemic closure. If I am successful, given that pic is equivalent to the axiom of distribution and that the latter is one of the conditions that discriminate between normal and non-normal modal logics, a main result of such a defence is that one potentially good reason to look for a formalization of the logic of “\(S\) is informed that \(p\)” among the non-normal modal logics, which reject the axiom, is also removed. This is not to argue that the logic of “\(S\) is informed that \(p\)” should be a normal modal logic, but that it could still be insofar as the objection that it could not be, based on the sceptical objection against pic, has been removed. In other word, I shall argue that the sceptical objection against pic fails, so such an objection provides no ground to abandon the normal modal logic B (also known as KTB) as a formalization of “\(S\) is informed that \(p\)”, which remains plausible insofar as this specific obstacle is concerned.


Epistemic closure Information closure Modal logic B (KTB)  Normal modal logic Non-normal modal logic  Principle of information closure Sceptical objection 



I discussed previous versions of this article as invited speaker at the European Science Foundation workshop on the Philosophy of Computer Science and AI (Ponta Delgado, Azores, 7–9 September 2011); the international conference on “Philosophy of Information”, Info-Metrics Institute, American University (Washington D.C., USA, 3 October, 2011); and the Philosophy of Information Workshop, Department of Philosophy and Cognitive Science, Lund University (Lund, Sweden, 9–11 May, 2013). I am indebted to Gregory Wheeler and the ESF; to Amos Golan and the Info-Metrics Institute at AU; to Frank Zenker and Lund University; and to the participants in such meetings for the fruitful opportunity to discuss my ideas and to receive so much helpful feedback. Penny Driscoll kindly copyedited the final version. The two anonymous reviewers of the journal provided many insightful comments and suggestions for improvements and saved me from several shortcomings and obscurities. The article is really much better thanks to them.


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Copyright information

© Springer Science+Business Media Dordrecht 2013

Authors and Affiliations

  1. 1.School of HumanitiesUniversity of HertfordshireHatfield, HertfordshireUK

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