Knowing whether A or B


The paper examines the logic and semantics of knowledge attributions of the form “s knows whether A or B”. We analyze these constructions in an epistemic logic with alternative questions, and propose an account of the context-sensitivity of the corresponding sentences and of their presuppositions.


  1. Aloni, M., Beaver, D., Clark, M., & van Rooij, R. (2007). The dynamics of topic and focus. In M. Aloni, A. Butler, & P. Dekker (Eds.), Questions in dynamic semantics, Vol. 17 of CRiSPI (pp. 123–145). Amsterdam: Elsevier.

  2. Aloni, M., & Égré, P. (2008). Alternative questions and knowledge attributions. The Philosophical Quarterly (forthcoming).

  3. Beaver D. (1997) Presupposition. In: van Benthem J., ter Meulen A.(eds) Handbook of logic and language. North Holland, Amsterdam

    Google Scholar 

  4. Chemla, E. (2008). Similarity: Towards a unified account of scalar implicatures, free choice permission and presupposition projection. Semantics and Pragmatics (to appear).

  5. de Cornulier B. (1982) Sur le sens des questions totales et alternatives. Langages, 16(67): 55–109

    Article  Google Scholar 

  6. Dretske F. I. (1970) Epistemic operators. The Journal of Philosophy 67(24): 1007–1023

    Article  Google Scholar 

  7. Fagin R., Halpern J. Y. (1988) Belief, awareness and limited reasoning. Artificial Intelligence 34: 39–76

    Article  Google Scholar 

  8. Groenendijk J., Stokhof M. (1982) Semantic analysis of Wh-complements. Linguistics and Philosophy 5(2): 175–233

    Google Scholar 

  9. Groenendijk, J., & Stokhof, M. (1984). Studies in the semantics of questions and the pragmatics of answers. Ph.D. thesis, Universiteit van Amsterdam.

  10. Heim I. (1994) Interrogative semantics and Karttunen’s semantics for know. In: Buchalla R., Mittwoch A.(eds) Proceedings of IATL 1. Akademon, Jerusalem, pp 128–144

    Google Scholar 

  11. Higginbotham, J. (1991). Either/or. In T. Sherer (Ed.), Proceedings of NELS 21 (pp. 143–155). Amherst, Ma: GLSA.

  12. Karttunen L. (1977) Syntax and semantics of questions. Linguistics and Philosophy 1: 3–44

    Article  Google Scholar 

  13. Larson R. K. (1985) On the syntax of disjunction scope. Natural Language and Linguistic Theory 3: 217–264

    Article  Google Scholar 

  14. Lewis D. K. (1979) Scorekeeping in a language game. Journal of Philosophical Logic 8: 339–359

    Article  Google Scholar 

  15. Lewis, D. K. (1982). ‘Whether’ report. In T. Pauli (Ed.), Philosophical essays dedicated to Lennart Åqvist on his fiftieth birthday. Filosofiska Studier.

  16. Lewis D. K. (1996) Elusive knowledge. Australasian Journal of Philosophy 74(4): 549–567

    Article  Google Scholar 

  17. Schaffer J. (2007) Knowing the answer. Philosophy and Phenomenological Research LXXV(2): 383–403

    Article  Google Scholar 

  18. Stalnaker R. (1978) Assertion. In: Stalnaker R.(eds) Context and content. Oxford University Press, Oxford, pp 78–95

    Google Scholar 

  19. Stanley J. (2005) Knowledge and practical interests. Oxford University Press, Oxford

    Book  Google Scholar 

  20. von Fintel K. (1999) NPI-licensing, Strawson-entailment, and context-dependency. Journal of Semantics 16(2): 97–148

    Article  Google Scholar 

  21. von Stechow A. (1991) Focusing and background operators. In: Abraham W.(eds) Discourse particles, Vol. 12 of Pragmatics and beyond. John Benjamins Publishing Company, Amsterdam, pp 37–84

    Google Scholar 

  22. Zimmermann T. E. (2000) Free choice disjunction and epistemic possibility. Natural Language Semantics 8: 225–290

    Article  Google Scholar 

Download references


We thank E. Chemla, H. van Ditmarsch, F. Roelofsen, B. Spector, and P. Schlenker for critical comments and helpful suggestions, as well as two anonymous reviewers. We also thank W. van der Hoek for his editorial assistance. Part of the research reported here was financially supported by the Dutch Organization for Scientific Research (NWO).

Open Access

This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.

Author information



Corresponding authors

Correspondence to Maria Aloni or Paul Égré or Tikitu de Jager.

Rights and permissions

Open Access This is an open access article distributed under the terms of the Creative Commons Attribution Noncommercial License (, which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.

Reprints and Permissions

About this article

Cite this article

Aloni, M., Égré, P. & de Jager, T. Knowing whether A or B. Synthese 190, 2595–2621 (2013).

Download citation


  • Knowledge
  • Alternative questions
  • Contextualism
  • Awareness
  • Relevant alternatives
  • Attention
  • Presupposition
  • Accommodation