The Principle of Non Contradiction - Ep. 1.3: Paraconsistent logic

Third episode (Season 1) of a series of talks with the logician and philosopher Graham Priest (CUNY) about contradiction.

Over the past decades, the logician and philosopher Graham Priest has dedicated himself to the herculean task of raising the vague contention that (some) contradictions might be true to the highest standards of clarity and analytic thinking.This unprecedented accomplishment was made possible, among other things, by the discovery and development of logical systems that block the Principle of Explosion (ex contraditione quodlibet), according to which from a contradiction any proposition whatsoever can be legitimately deduced. These systems, known as paraconsistent logics, opened the way for a non-trivial treatment of true contradictions, or dialetheias. In this episode, Prof. Priest discusses the Principle of Explosion and outlines the history of its denial.

Very few philosophers dared to question the Principle of Non Contradiction, which says that contradictions cannot be true. The principle has gone so unquestioned that hardly any philosopher since Aristotle tried to defend it. Graham Priest belongs to the small number of philosophers who - in the good company of Heraclitus and Hegel - have dared to question it. He thinks that some contradictions are true. Here is why.