The Henkin Sentence

  • Volker Halbach
  • Albert Visser
Part of the Studies in Universal Logic book series (SUL)


In this paper we discuss Henkin’s question concerning a formula that has been described as expressing its own provability. We analyze Henkin’s formulation of the question and the early responses by Kreisel and Löb and sketch how this discussion led to the development of provability logic. We argue that, in addition to that, the question has philosophical aspects that are still interesting.


Self-reference Fixed Points Second Incompleteness Theorem Provability Logic 



We thank Volodya Shavrukov for his comments on the penultimate version.


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Copyright information

© Springer International Publishing Switzerland 2014

Authors and Affiliations

  1. 1.New CollegeOxfordUK
  2. 2.Philosophy, Faculty of HumanitiesUtrecht UniversityUtrechtThe Netherlands

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