Hostname: page-component-cd9895bd7-dk4vv Total loading time: 0 Render date: 2024-12-26T03:50:33.075Z Has data issue: false hasContentIssue false

SELF-REFERENCE IN ARITHMETIC I

Published online by Cambridge University Press:  07 October 2014

VOLKER HALBACH*
Affiliation:
Oxford University
ALBERT VISSER*
Affiliation:
Utrecht University
*
*NEW COLLEGE OXFORD, OX1 3BN, ENGLAND E-mail: volker.halbach@new.ox.ac.uk
PHILOSOPHY, FACULTY OF HUMANITIES UTRECHT UNIVERSITY JANSKERHOF 13 3512 BL UTRECHT, THE NETHERLANDS E-mail: albert.visser@phil.uu.nl

Abstract

A Gödel sentence is often described as a sentence saying about itself that it is not provable, and a Henkin sentence as a sentence stating its own provability. We discuss what it could mean for a sentence of arithmetic to ascribe to itself a property such as provability or unprovability. The starting point will be the answer Kreisel gave to Henkin’s problem. We describe how the properties of the supposedly self-referential sentences depend on the chosen coding, the formulae expressing the properties and the way a fixed points for the formulae are obtained. This paper is the first of two papers. In the present paper we focus on provability. In part II, we will consider other properties like Rosser provability and partial truth predicates.

Type
Research Article
Copyright
Copyright © Association for Symbolic Logic 2014 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

BIBLIOGRAPHY

Auerbach, D. D. (1985). Intensionality and the Gödel theorems. Philosophical Studies, 48, 337351.Google Scholar
Blanck, R. (2011). Metamathematical fixed points. Philosophical Communications Red series 41, Gothenburg: University of Gothenburg.Google Scholar
Boolos, G. (1993). The Logic of Provability. Cambridge: Cambridge University Press.Google Scholar
Feferman, S. (1960). Arithmetization of metamathematics in a general setting. Fundamenta Mathematicae, 49, 3591.Google Scholar
Franks, C. (2009). The Autonomy of Mathematical Knowledge: Hilbert’s Program Revisited. Cambridge: Cambridge University Press.Google Scholar
Gödel, K. (1931). Über formal unentscheidbare Sätze der Principia Mathematica und verwandter Systeme I. Monatshefte für Mathematik, 38, 173198.Google Scholar
Heck, R. (2007). Self-reference and the languages of arithmetic. Philosophia Mathematica, 15, 129.Google Scholar
Henkin, L. (1952). A problem concerning provability. Journal of Symbolic Logic, 17, 160.Google Scholar
Henkin, L. (1954). Review of G. Kreisel: On a problem of Henkin’s. Journal of Symbolic Logic ,19, 219220.Google Scholar
Hilbert, D., & Bernays, P. (1939). Grundlagen der Mathematik II (second edition: 1970). Berlin: Springer .Google Scholar
Jeroslow, R. (1973). Redundancies in the Hilbert-Bernays derivability conditions for Gödel’s second incompleteness theorem. Journal of Symbolic Logic, 38, 359367.Google Scholar
Kreisel, G. (1953). On a problem of Henkin’s. Indagationes Mathematicae, 15, 405406.Google Scholar
Kreisel, G., & Takeuti, G. (1974). Formally self-referential propositions for cut free classical analysis and related systems. Technical report, Warsaw: Polska Akademia Nauk.Google Scholar
Löb, M. H. (1955). Solution of a problem of Leon Henkin. Journal of Symbolic Logic, 20, 115118.Google Scholar
McGee, V. (1992). Maximal consistent sets of instances of Tarski’s schema (T). Journal of Philosophical Logic, 21, 235241.Google Scholar
Milne, P. (2007). On Gödel sentences and what they say. Philosophia Mathematica, 15, 193226.Google Scholar
Priest, G. (1997). Yablo’s paradox. Analysis, 57, 236242.CrossRefGoogle Scholar
Russell, B. (1940). An Enquiry into Meaning and Truth. London: George Allen and Unwin.Google Scholar
Skyrms, B. (1984). Intensional aspects of semantical self-reference. In Martin, R. L., editor. Recent Essays on Truth and the Liar Paradox, Oxford: Oxford University Press, 119131.Google Scholar
Smoryński, C. (1985). Self-Reference and Modal Logic. Universitext. New York, Berlin, Heidelberg, and Tokyo: Springer.Google Scholar
Smoryński, C. (1991). The development of self-reference: Löb’s theorem. In Drucker, T., editor. Perspectives on the History of Mathematical Logic, Boston: Birkhäuser, pp. 110133.Google Scholar
Solovay, R. (1985). Explicit Henkin sentences. Journal of Symbolic Logic, 50, 9193.Google Scholar
Tarski, A., Mostowski, A., & Robinson, R. M. (1953). Undecidable Theories. Amsterdam: North Holland.Google Scholar
Visser, A. (2005). Faith & Falsity: A study of faithful interpretations and false ${\rm{\Sigma }}_1^0$-sentences. Annals of Pure and Applied Logic, 131(13), 103131.Google Scholar
Visser, A. (2014). Jumping in arithmetic. Logic Group Preprint Series, Vol. 319, Utrecht University, http://www.phil.uu.nl/preprints/lgps/.Google Scholar
Yablo, S. (1993). Paradox without self-reference. Analysis, 53, 251252.Google Scholar