Natural Language Semantics

, Volume 8, Issue 4, pp 255-290

First online:

Free Choice Disjunction and Epistemic Possibility

  • Thomas Ede Zimmermann

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This paper offers an explanation of the fact that sentences of the form (1) ‘X may A or B’ may be construed as implying (2) ‘X may A and X may B’, especially if they are used to grant permission. It is suggested that the effect arises because disjunctions are conjunctive lists of epistemic possibilities. Consequently, if the modal may is itself epistemic, (1) comes out as equivalent to (2), due to general laws of epistemic logic. On the other hand, on a deontic reading of may, (2) is only implied under exceptional circumstances – which usually obtain when (1) is used performatively.