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'.

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.

Epistemology

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

Political philosophy

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

Ethics

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

See also

Further reading

  • Brewer, B. (2011). The Inconsistent Triad. , 68.
  • Howard-Snyder, F., Howard-Snyder, D., & Wasserman, R. (2009). (4th Edition). New York: McGraw-Hill. (p. 336) ISBN 978-0-07-340737-1