Hostname: page-component-89b8bd64d-j4x9h Total loading time: 0 Render date: 2026-05-09T07:47:41.575Z Has data issue: false hasContentIssue false
  • English
  • Français

KNOWLEDGE, JUSTIFICATION, AND ADEQUATE REASONS

Part of: General logic

Published online by Cambridge University Press:  02 July 2020

PAUL ÉGRÉ ,
PAUL MARTY  and
BRYAN RENNE
PAUL ÉGRÉ
Affiliation:
INSTITUT JEAN-NICOD CNRS/ENS/EHESS, PSL UNIVERSITY 29, RUE D'ULM - 75005 PARIS, FRANCE E-mail: paul.egre@ens.fr
PAUL MARTY
Affiliation:
LEIBNIZ-ZAS BERLIN BERLIN, GERMANY and UNIVERSITY COLLEGE LONDON LONDON, UK E-mail: p.marty@ucl.ac.uk
BRYAN RENNE
Affiliation:
UNIVERSITY OF SASKATCHEWAN SASKATOON, SK, CANADA E-mail: bryan@renne.org
Get access Rights & Permissions [Opens in a new window]

Abstract

Is knowledge definable as justified true belief (“JTB”)? We argue that one can legitimately answer positively or negatively, depending on whether or not one’s true belief is justified by what we call adequate reasons. To facilitate our argument we introduce a simple propositional logic of reason-based belief, and give an axiomatic characterization of the notion of adequacy for reasons. We show that this logic is sufficiently flexible to accommodate various useful features, including quantification over reasons. We use our framework to contrast two notions of JTB: one internalist, the other externalist. We argue that Gettier cases essentially challenge the internalist notion but not the externalist one. Our approach commits us to a form of infallibilism about knowledge, but it also leaves us with a puzzle, namely whether knowledge involves the possession of only adequate reasons, or leaves room for some inadequate reasons. We favor the latter position, which reflects a milder and more realistic version of infallibilism.

Keywords

knowledgebeliefjustification logicsadequate reasonsinfallibilismexternalism

MSC classification

Primary: 03B42: Logics of knowledge and belief (including belief change)
Secondary: 03B45: Modal logic (including the logic of norms)

Information

Type
Research Article
Information
The Review of Symbolic Logic , Volume 14 , Issue 3 , September 2021 , pp. 687 - 727
Check for updates
Copyright
© Association for Symbolic Logic, 2020

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.)

Article purchase

Temporarily unavailable

References

BIBLIOGRAPHY

Armstrong, D. M. (1973). Belief, Truth and Knowledge. Cambridge: Cambridge University Press.10.1017/CBO9780511570827CrossRefGoogle Scholar
Artemov, S. (2008). The logic of justification. Review of Symbolic Logic, 1(4), 477–513.CrossRefGoogle Scholar
Artemov, S., & Fitting, M. (2011). Justification logic. In Zalta, E. N., editor. The Stanford Encyclopedia of Philosophy. Summer 2020 edition. https://plato.stanford.edu/archives/sum2020/entries/logic-justification/.Google Scholar
Baltag, A., Renne, B., & Smets, S. (2012). The logic of justified belief change, soft evidence and defeasible knowledge. In Ong, L. & de Queiroz, R., editors. Logic, Language, Information and Computation: 19th International Workshop, WoLLIC 2012, Buenos Aires, Argentina, September 3–6, 2012. Lecture Notes in Computer Science, Vol. 7456. Berlin: Springer-Verlag, pp. 168–190.10.1007/978-3-642-32621-9_13CrossRefGoogle Scholar
Baltag, A., Renne, B., & Smets, S.. (2014). The logic of justified belief, explicit knowledge, and conclusive evidence. Annals of Pure and Applied Logic, 165(1), 49–81.CrossRefGoogle Scholar
Braüner, T. (2006). Hybrid logic. In Zalta, E. N., editor. The Stanford Encyclopedia of Philosophy. Summer 2020 edition. https://plato.stanford.edu/archives/sum2020/entries/logic-hybrid/.Google Scholar
Chellas, B. F. (1980). Modal Logic: An Introduction. New York: Cambridge University Press.CrossRefGoogle Scholar
Chisholm, R. M. (1977). Theory of Knowledge, 2nd edition. Englewood Cliffs, NJ: Prentice Hall.Google Scholar
Clark, M. (1963). Knowledge and grounds: A comment on Mr. Gettier’s paper. Analysis, 24(2), 46–48.CrossRefGoogle Scholar
Dretske, F. (1971). Conclusive reasons. Australasian Journal of Philosophy, 1(49), 1–22.CrossRefGoogle Scholar
Dutant, J. (2010). Knowledge, Methods, and the Impossibility of Error. PhD thesis, University of Geneva.Google Scholar
Dutant, J. (2015). Methods Models for Belief and Knowledge. London: Manuscript.Google Scholar
Égré, P. (2017). Knowledge as de re true belief? Synthese, 194(5), 1517–1529.CrossRefGoogle Scholar
Fitelson, B. (2010). Strengthening the case for knowledge from falsehood. Analysis, 70(4), 666–669.CrossRefGoogle Scholar
Fumerton, R. (2002). Theories of justification. In The Oxford Handbook of Epistemology. Oxford: Oxford University Press, pp. 204–233.CrossRefGoogle Scholar
Gettier, E. (1963). Is justified true belief knowledge? Analysis, 23, 121–123.10.1093/analys/23.6.121CrossRefGoogle Scholar
Goldman, A. I. (1976). Discrimination and perceptual knowledge. The Journal of Philosophy, 73(20), 771–791.CrossRefGoogle Scholar
Goldman, A. I.. (1979). What is justified belief? In Pappas, G. S., editor. Justification and Knowledge. Dordrecht: Reidel, pp. 1–23.Google Scholar
Harman, G. H. (1970). Knowledge, reasons, and causes. The Journal of Philosophy, 67(21), 841–855.CrossRefGoogle Scholar
Kahneman, D. & Frederick, S. (2002). Representativeness revisited: Attribute substitution in intuitive judgment. In Gilovich, T., Griffin, D., & Kahneman, D., editors. Heuristics and Biases: The Psychology of Intuitive Judgment. Cambridge: Cambridge University Press, pp. 49–81.CrossRefGoogle Scholar
Kratzer, A. (2002). Fact: Particulars or information units? Linguistics and Philosophy, 25, 655–670.CrossRefGoogle Scholar
Lehrer, K. (2000). Theory of Knowledge, 2nd edition. Boulder, CO:Westview Press.Google Scholar
Lehrer, K. & Paxson, T. Jr. (1969). Knowledge: Undefeated justified true belief. Journal of Philosophy, 66, 225–237.CrossRefGoogle Scholar
Neta, R. (2011). A refutation of Cartesian fallibilism. Noûs, 45(4), 658–695.CrossRefGoogle Scholar
Sorensen, R. (2016). Fugu for logicians. Philosophy and Phenomenological Research, 92(1), 131–144.10.1111/phpr.12117CrossRefGoogle Scholar
Sosa, E. (1974). How do you know? American Philosophical Quarterly, 11(2), 113–122.Google Scholar
Sosa, E. (1979). Epistemic presupposition. In Pappas, G., editor. Justification and Knowledge. Dordrecht: Holland, pp. 79–92.CrossRefGoogle Scholar
Spinoza Ethica. (1677). Latin and English Versions. Available from http://ethicadb.org/.Google Scholar
Turri, J. (2012). Is knowledge justified true belief? Synthese, 184(3), 247–259.CrossRefGoogle Scholar
van Benthem, J. & Pacuit, E. (2011). Dynamic logics of evidence-based beliefs. Studia Logica, 99(1–3), 61–92.CrossRefGoogle Scholar
van Dalen, D. (1994). Logic and Structure. Berlin: Springer-Verlag.CrossRefGoogle Scholar
Warfield, T. (2005). Knowledge from falsehood. Philosophical Perspectives, 405–416.10.1111/j.1520-8583.2005.00067.xCrossRefGoogle Scholar
Williamson, T. (2000). Knowledge and its limits. Oxford: Oxford University Press.Google Scholar
Zagzebski, L. (1994). The inescapability of Gettier problems. The Philosophical Quarterly, 44(74), 65–73.CrossRefGoogle Scholar