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[email protected] on 19 September 2018 Journal of Semantics, 00, 2018, 1–18 doi:10.1093/jos/ffy013 Advance Access Publication Date: Independence Day? Matthew Mandelkern All Souls College, Oxford, OX1 4AL, UK E-mail:
[email protected] Daniel Rothschild University College London, Gower Street, London, WC1E 6BT, UK E-mail:
[email protected] First version received 25 June 2017; Second version received 13 September 2017; Accepted 10 July 2018 1 INTRODUCTION Two recent and influential papers, van Rooij 2007 and Lassiter 2012, propose solutions to the proviso problem that make central use of related notions of independence—qualitative in the first case, probabilistic in the second. We argue here that, if these solutions are to work, they must incorporate an implicit assumption about presupposition accommodation, namely that accommodation does not interfere with existing qualitative or probabilistic independencies. We show, however, that this assumption is implausible, as updating beliefs with conditional information does not in general preserve independencies. We conclude that the approach taken by van Rooij and Lassiter does not succeed in resolving the proviso problem. 2 THE PROVISO PROBLEM Standard theories of semantic presupposition,1 in particular satisfaction theory, predict that the strongest semantic presupposition of an indicative conditional with the form