Journal of Logic, Language and Information

, Volume 20, Issue 4, pp 445–474

The Hamiltonian Syllogistic


DOI: 10.1007/s10849-011-9144-y

Cite this article as:
Pratt-Hartmann, I. J of Log Lang and Inf (2011) 20: 445. doi:10.1007/s10849-011-9144-y


This paper undertakes a re-examination of Sir William Hamilton’s doctrine of the quantification of the predicate. Hamilton’s doctrine comprises two theses. First, the predicates of traditional syllogistic sentence-forms contain implicit existential quantifiers, so that, for example, All p is q is to be understood as All p is some q. Second, these implicit quantifiers can be meaningfully dualized to yield novel sentence-forms, such as, for example, All p is all q. Hamilton attempted to provide a deductive system for his language, along the lines of the classical syllogisms. We show, using techniques unavailable to Hamilton, that such a system does exist, though with qualifications that distinguish it from its classical counterpart.


SyllogismsNatural language and logicComplexityProof-theory

Copyright information

© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  1. 1.School of Computer ScienceUniversity of ManchesterManchesterUK