Studia Logica

, Volume 71, Issue 1, pp 119–132

Naïve Comprehension and Contracting Implications

  • Susan Rogerson
  • Sam Butchart

DOI: 10.1023/A:1016391109231

Cite this article as:
Rogerson, S. & Butchart, S. Studia Logica (2002) 71: 119. doi:10.1023/A:1016391109231


In his paper [6], Greg Restall conjectured that a logic supports a naïve comprehension scheme if and only if it is robustly contraction free, that is, if and only if no contracting connective is definable in terms of the primitive connectives of the logic. In this paper, we present infinitely many counterexamples to Restall's conjecture, in the form of purely implicational logics which are robustly contraction free, but which trivialize naïve comprehension.

Naïve comprehensioncontractionnon-classical logicRestall's conjecture

Copyright information

© Kluwer Academic Publishers 2002

Authors and Affiliations

  • Susan Rogerson
    • 1
  • Sam Butchart
    • 1
  1. 1.Monash UniversityVictoriaAustralia