Dialetheism is the view that some contradictions are true. This is a view which runs against orthodoxy in logic and metaphysics since Aristotle, and has implications for many of the core notions of philosophy. Doubt Truth to Be a Liar explores these implications for truth, rationality, negation, and the nature of logic, and develops further the defence of dialetheism first mounted in Priest's In Contradiction, a second edition of which is also available.

Graham Priest is Boyce Gibson Professor of Philosophy at the University of Melobourne, and Arché Professorial Fellow at the University of St Andrews

• I. Truth


• 1: Aristotle on the Law of Non-Contradiction


• 2: Theories of Truth


• 3: Trivialism


• II. Negation


• 4: Contradiction


• 5: Boolean Negation


• 6: Denial and Rejection


• III. Rationality


• 7: Rational Belief


• 8: Belief Revision


• 9: Consistency and the Empirical Sciences


• IV. Logic


• 10: Logic and Revisability


• 11: Validity


• 12: Logical Pluralism