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Inconsistent triad

An inconsistent triad is a set of three propositions that cannot all be true together. For example, 'She was an orphan; Tim outlived her; Tim was her father'.

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Jul 10, 2026
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An inconsistent triad is a set of three propositions that cannot all be true together. For example, 'She was an orphan; Tim outlived her; Tim was her father'.1

All inconsistent triads lead to trilemmas:

  • If A and B are true, C must be false.
  • If A and C are true, B must be false.
  • If B and C are true, A must be false.2

Epistemology

  1. Knowledge is justified true belief.3
  2. Humans cannot provide justification for their beliefs.4
  3. Humans possess knowledge.5

Political philosophy

  1. A just society maximizes individual liberty.6
  2. A just society maximizes material equality.7
  3. A just society cannot maximize both liberty and equality.8

Ethics

  1. Actions that maximize overall well-being are morally right.9
  2. Lying can sometimes maximize overall well-being.10
  3. Lying is always morally wrong.11
See also

See also

References

References

  1. "The Oxford companion to philosophy". Choice Reviews Online. 33 (5): 33–2495–33-2495. 1996-01-01. doi:10.5860/CHOICE.33-2495 (inactive 1 July 2025). S2CID 142841293.{{cite journal}}: CS1 maint: DOI inactive as of July 2025 (link)
  2. Sullivan, Scott M. (2005-10-26). An Introduction To Traditional Logic: Classical Reasoning For Contemporary. Booksurge Publishing. ISBN 978-1-4196-1671-6.
  3. de Grefte, Job (2023-02-01). "Knowledge as Justified True Belief". Erkenntnis. 88 (2): 531–549. doi:10.1007/s10670-020-00365-7. ISSN 1572-8420.
  4. Hume, David (2020), An Enquiry concerning Human Understanding, Oxford University Press, doi:10.1093/owc/9780199549900.001.0001/isbn-9780199549900 (inactive 1 July 2025), ISBN 978-0-19-192173-5, retrieved 2025-02-21{{citation}}: CS1 maint: DOI inactive as of July 2025 (link)
  5. Descartes, René; Moriarty, Michael (2008). Meditations on first philosophy: with selections from the Objections and replies. Oxford: Oxford University Press. ISBN 978-0-19-280696-3.
  6. Nozick, Robert (1974). Anarchy, State, and Utopia. New York: Basic Books.
  7. Rawls, John (1971). A Theory of Justice: Original Edition. Harvard University Press. doi:10.2307/j.ctvjf9z6v. ISBN 978-0-674-88010-8. JSTOR j.ctvjf9z6v.
  8. Berlin, Isaiah (2002-03-07), Berlin, Isaiah; Hardy (eds.), "Two Concepts of Liberty", Liberty, Oxford University Press, pp. 166–217, doi:10.1093/019924989x.003.0004, ISBN 978-0-19-924989-3, retrieved 2025-02-20{{citation}}: CS1 maint: work parameter with ISBN (link)
  9. Bentham, Jeremy (1890). Utilitarianism. Progressive Publishing Company.
  10. Greasley, Kate (2019). "The Morality of Lying and the Murderer at the Door". Law and Philosophy. 38 (5/6): 439–452. doi:10.1007/s10982-018-09342-2. ISSN 0167-5249. JSTOR 45284255.
  11. Wood, Allen W. (2011). "Kant and the right to lie reviewed essay: On a supposed right to lie from philanthropy, by Inmanuel Kant (1797)". Eidos (15): 96–117. ISSN 1692-8857.
Further reading

Further reading