Is Having Contradictory Beliefs Possible? Discussion and Critique of Arguments for the Psychological Principle of Non-Contradiction
PDF (Polski)


principle of non-contradiction
principle of charity
intentional stance
belief ascription
folk psychology



The aim of this paper is to present and analyze arguments provided for the Psychological Principle of Non-Contradiction which states that one cannot have, or cannot be described as having, contradictory beliefs. By differentiating two possible interpretations of PNC, descriptive and normative, and examining arguments (ontological and methodological) provided for each of them separately I point out the flaws in reasoning in these arguments and difficulties with aligning PNC with the empirical data provided by research done in cognitive and clinical psychology. I claim that PNC cannot be derived from any metaphysical stance regarding the mental phenomena and that having contradictory beliefs should be regarded as possible. Furthermore, I argue that interpreting a subject as having contradictory beliefs, and therefore abandoning PNC, can be more effective in explaining the phenomena of contradictory beliefs and irrational behaviour than solutions consistent with the PNC.

PDF (Polski)


Bar-Hillel, M., Neter, E. (1993). How Alike Is It Versus How Likely Is It: A Disjunction Fallacy in Probability Judgments. Journal of Personality and Social Psychology, 65(6), 1119–1131.

Bortolotti, L. (2010). Delusions and Other Irrational Beliefs. Oxford: Oxford University Press.

Breen, N., Caine, D., Coltheart, M., Hendy, J., Roberts, C. (2000). Towards an Understanding of Delusions of Misidentification: Four Case Studies. Mind & Language, 15(1), 74–110.

Campbell, J. (2001). Rationality, Meaning and the Analysis of Delusion. Philosophy, Psychiatry, & Psychology, 8(2–3), 89–100.

Carroll, L. (1995). What the Tortoise Said to Achilles. Mind, 104(416), 691–693.

Ciecierski, T. (2017). Attitudes and Normativity. Axiomathes, 27(3), 265–283.

Cohen, L. J. (1981). Can Human Irrationality Be Experimentally Demonstrated? The Behavioral and Brain Sciences, 4(3), 317–370.

Currie, G. (2000). Imagination, Delusion and Hallucinations. Mind & Language, 15(1), 168–183.

Davidson, D. (1992). Przekonania a podstawy znaczenia. W: D. Davidson (red.), Eseje o prawdzie, języku i umyśle (s. 118–140). Warszawa: PWN.

Davidson, D. (1992). Ku jednolitej teorii znaczenia i działania. W: D. Davidson (red.), Eseje o prawdzie, języku i umyśle (s. 141–159). Warszawa: PWN.

Dennett, D. (1978). Brainstorms, Cambridge: MIT Press.

Dennett, D. (1987). True Believers: The Intentional Strategy and Why It Works. W: D. Dennett (red.), The Intentional Stance (s. 13–36). Cambridge: MIT Press.

Dennett, D. (1981). Making Sense of Ourselves. Philosophical Topics, 12(1), 63–81.

Dennett, D. (2015). Not Just a Fine Trip Down Memory Lane: Comments on the Essays on Content and Consciousness. W: C. Muñoz-Suárez, F. De Brigard (red.), Content and Consciousness Revisited (s. 199–218). New York: Springer.

Dub, R. (2015). The Rationality Assumption. W: C. Muñoz-Suárez, F. De Brigard (red.), Content and Consciousness Revisited (s. 93–111). New York: Springer.

Egan, A. (2008). Imagination, Delusion, and Self-Deception. W: T. Bayne, J. Fernandez (red.), Delusion and Self-Deception: Affective and Motivational Influences on Belief Formation (Macquarie Monographs in Cognitive Science) (s. 263–280). Londyn: Psychology Press.

Ellis, H. D., Young, A. W. (1990). Accounting for Delusional Misidentifications, British Journal of Psychiatry, 157(2), 239–248.

Evnine, s. J. (1989). Understanding Madness? Ratio, 2(1), 1–18.

Fiedler, K. (1988). The Dependence of the Conjunction Fallacy on Subtle Linguistic Factors. Psychological Research, 50(2), 123–129.

Gottlieb, P. (2007). Aristotle on Non-Contradiction. The Stanford Encyclopedia of Philosophy, pobrane z:

Hodges, W. (1977). Logic. Harmondsworth: Penguin Books.

Joseph, M. (2004). Donald Davidson. Chesham: Acumen.

Kahneman, D., Tversky, A. (1971). Belief in the Law of Small Numbers. Psychological Bulletin, 76(2), 105–110.

Kahneman, D., Tversky, A. (1983). Extensional Versus Intuitive Reasoning: The Conjunction Fallacy in Probability Judgment. Psychological Review, 90(4), 293–315.

Konold, C., Pollatsek, A., Well, A., Lohmeier, J., Lipson, A. (1993). Inconsistencies in Students’ Reasoning about Probability. Journal for Research in Mathematics Education, 24(5), 392–414.

Kripke, s. (1979). A Puzzle About Belief. W: A.Margalit (red.), Meaning and Use (s. 239–283). Dordrecht: D. Reidel.

Lewis, H. A., Cooper, D. (1979). The Argument from Evolution. Proceedings of the Aristotelian Society, 53, 207–237.

Łukasiewicz, J. (1987). O zasadzie sprzeczności u Arystotelesa. Warszawa: PWN.

Maddy, P. (2012). The Philosophy of Logic. The Bulletin of Symbolic Logic, 18(4), 481–504

Manktelow, K. I. (1981). Recent Developments in Research on Wason’s Selection Task. Current Psychological Reviews, 1(3), 257–268.

Marcus, R. B. (1983). Rationality and Believing the Impossible. W: R.B.Marcus (red.), Modalities: Philosophical Essays (s. 143–162). New York: Oxford University Press.

McKay, R., Cipolotti, L. (2007). Attributional style in a case of Cotard delusion. Consciousness and Cognition, 16(2), 349–359.

Nishio, Y., Mori, E. (2012). Delusions of Death in a Patient with Right Hemisphere Infraction. Cognitive and Behavioural Neurology, 25(4), 216–223.

Pacherie, E., Bayne, T. (2005). In Defence of the Doxastic Conception of Delusions. Mind & Language, 20(2), 163–188.

Quine, W. V. O. (1999). Słowo i przedmiot. Warszawa: Aletheia.

Quine, W. V. O., Ullian, J. s. (1978). The Web of Belief. New York: Random House.

Ramsey, F. (1926). Truth and Probability. W: R.B. Braithwaite, The Foundations of Mathematics and other Logical Essays (s. 156–198). New York: Harcourt Brace.

Ramsey, F. (1931). General Propositions and Causality. W: D. H. Mellor (red.), The Foundations of Mathematics (s. 145–163), New York: Harcourt, Brace and Company.

Richard, M. (1983). Direct Reference and Ascriptions of Belief. Journal of Philosophical Logic, 12(4), 425–452.

Rudiak-Gould, P. (2010). Being Marshallese and Christian: a case of multiple identities and contradictory beliefs. Culture and Religion: An Interdisciplinary Journal, 11(1), 69–87.

Schwitzgebel, E. (2010). Acting Contrary to Our Professed Beliefs or The Gulf Between Occurrent Judgment and Dispositional Belief. Pacific Philosophical Quarterly, 91(4), 531–553.

Slater, B. H. (1995). Paraconsistent Logics? Journal of Philosophical Logic, 24(4), 451–454.

Sober, E. (1978). Psychologism. Journal for the Theory of Social Behaviour, 8(2), 165–191.

Stich, s. (1981). Dennett on Intentional Systems. Philosophical Topics, 12(1), 39–62.

Stich, s. (1985). Could Man Be Irrational Animal? Synthese, 64(1), 115–135.

Thagard, P., Nisbett, R. (1983). Rationality and Charity. Philosophy of Science, 50, 250–267.

Wason, P. C. (1968). Reasoning About a Rule. The Quarterly Journal of Experimental Psychology, 20(3), 273–281.

Wason, P. C. (1969). Regression in Reasoning? British Journal of Psychology, 60(4), 471–480.

Wittgenstein, L. (2000a). Traktat logiczno-filozoficzny. Warszawa: PWN.

Wittgenstein, L. (2000b). Uwagi o podstawach matematyki. Warszawa: Wydawnictwo KR.

Wittgenstein, L. (2014). O pewności. Warszawa: Aletheia.