Graham Priest on Dialetheism, True Contradictions, the Liar Paradox & Why Classical Logic Isn’t Enough

What if some contradictions are not mistakes — but truths? For over 2,500 years, Western philosophy has treated contradiction as catastrophic. From Aristotle’s law of non-contradiction to modern formal systems, logic has operated under one sacred assumption: a statement cannot be both true and false. But what if that assumption is wrong? In this deep, wide-ranging conversation, I sit down with Graham Priest, one of the world’s most influential philosophers of logic and the leading defender of dialetheism — the view that some contradictions are true. We explore: What dialetheism really means Why the liar paradox still unsettles logicians How paraconsistent logic blocks “explosion” (the idea that from a contradiction, anything follows) Whether classical logic is incomplete rather than universal What Buddhist philosophy and Nāgārjuna understood about contradiction And whether AI systems may eventually require non-classical logics to model human reasoning Far from being an abstract puzzle, the liar paradox exposes deep tensions in how we understand truth, self-reference, and rationality itself. If contradictions can be true, then the foundations of logic, mathematics, metaphysics — and even artificial intelligence — may need rethinking. We also move beyond formal systems into lived philosophy: Graham’s journey from Christianity to atheism His engagement with Buddhist thought The limits of decision theory The discipline of karate as a philosophical practice This is not merely a discussion of symbolic logic. It is a conversation about the limits of reason. About what happens when our most trusted intellectual tools reach their breaking point. And about whether embracing contradiction might expand — rather than destroy — rational inquiry. If your background is in technology, computer science, AI, or engineering, this episode may challenge assumptions you didn’t even realize you were making. If your background is in philosophy, it may unsettle what you thought was settled. And if you care about the future of thought itself, this conversation is essential. You can see the original video recording here: https://www.singularityweblog.com/graham-priest-dialetheism/ As always, you can listen to or download the audio file above or scroll down and watch the video interview in full. To show your support, you can write a review on iTunes, make a direct donation, or become a patron on Patreon.