54. Graham Priest on Logic and Buddhism

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Graham Priest joins Peter to discuss non-classical logic and its connections with Buddhist patterns of reasoning.



Further Reading

Graham Priest's website which includes a list of his publications.


Sjoerd van der… on 26 November 2017

Graham Priest

Fascinated by Priest's talk about developments in western [european/american] thinking about formal logic. Especially his view of 'us, in the west' becoming gradually more aware of logic's metaphysical underpinnings. Very revealing to me, that those underpinnings were completely unnoticed until the late sixties last century [apart from my countryman Brouwer, seemingly already having a hunch of it in the interbellum]. Hopefully, unimpeded communication accross cultures and physical borders [of which this podcast to me is a great example] is contributing to a really serious dialogue between 'west' [where I have my roots] and 'east'. Hopefully, at least in philosphical exchanges, even the slightest hint of 'western/white superiority' by now belongs to the past. 

Keep going, Mr Adamson

Philip Stanfield on 27 November 2017

Priest's ignorance of Neoplatonism

I listened to Priest years ago when he was interviewed on 'The Philosopher's Zone' in Australia and he spoke very well about the essential importance of Westerners getting to know and benefit from Asian philosophies, but what of his own culture?

He exemplifies the determined ignorance of Western academics concerning Neoplatonism (which I refer to as the pornography of academic philosophers) and, given his interest in contradiction, should acquaint himself with it. It is a current in Western philosophy that has possibly had a greater influence on the culture of his origins than either Plato or Aristotle, on both of whom it drew.

Contradiction is the basis of its method for acquiring knowledge, starting from an initial division within a unity - knower and known, subject and its object.

Priest spoke of Hegel (the consummate Neoplatonist) but made no mention of others who contributed to the development of that current prior to him e.g. Cusanus, who failed Aristotle on precisely the point Priest spoke so much about:

'NICHOLAS: I laud your remarks. And I add that also in another manner Aristotle closed off to himself a way for viewing the truth. For, as we mentioned earlier, he denied that there is a Substance of substance or a Beginning of beginning. Thus, he would also have denied that there is a Contradiction of contradiction. But had anyone asked him whether he saw contradiction in contradictories, he would have replied, truly, that he did. Suppose he were thereupon asked: “If that which you see in contradictories you see antecedently (just as you see a cause antecedently to its effect), then do you not see contradiction without contradiction?” Assuredly, he could not have denied that this is so. For just as he saw that the contradiction in contradictories is contradiction of the contradictories, so prior to the contradictories he would have seen Contradiction before the expressed contradiction (even as the theologian Dionysius saw God to be, without opposition, the Oppositeness of opposites; for prior to [there being any] opposites it is not the case that anything is opposed to oppositeness). But even though the Philosopher failed in first philosophy, or mental philosophy, nevertheless in rational and moral [philosophy] he wrote many things very worthy of complete praise. Since these things do not belong to the present speculation, let it suffice that we have made the preceding remarks about Aristotle.’

Nicholas of Cusa, De Li Non Aliud (‘On God as Not-Other’), 1461-2, in Nicholas of Cusa on God as Not-other, Trans., Jasper Hopkins, The Arthur J. Banning Press, Minneapolis, 1999, 1108-1166, 89, 1150

Hegel was immensely indebted to Cusanus (a whole other subject - 7 of the 9 histories he cited as sources for his Lectures on the History of Philosophy name and discuss him - Buhle's Geschichte [which Hegel paid close attention to for his writing on Bruno, but never named] in particular, at length) and for that reason, never named him.

Marx and Engels took what Hegel achieved and stood it on its feet by making materialism dialectical. It is the epistemology of the future. An epistemology with contradiction and negation at its core.

In reply to by Philip Stanfield

Peter Adamson on 28 November 2017

Neoplatonism and contradiction

Well, I wouldn't infer that Prof Priest is ignorant of Neoplatonism just because he didn't mention it in this brief interview. Actually in general I would reject your implication that Neoplatonism is committed to denying the principle of non contradiction; I can't imagine any of the late ancient Neoplatonists admitting that at least in the context of philosophical logic. They might engage in certain paradoxical formulations but that is rather different than what we are talking about here where you develop (quasi-) formal systems of reasoning that depart from the PNC. Cusa by contrast could probably be included in a full history of non-dialethic reasoning, but that just shows how different he is from earlier Platonists.

And I would also gently suggest that if you want to get people to be interested in Cusa, who let's face it is not that well known a figure despite being fascinating and important for Renaissance thought, accusing them of "determined ignorance" is probably not the right strategy. I always think that getting people to broaden their historical interests involves seduction, not scolding.

In reply to by Peter Adamson

Philip Stanfield on 29 November 2017

Priest's ignorance of Neoplatonism


I have listened to many of your podcasts and all of the ones I listened to were about 30 mins. or less duration. Your interview of Priest, as far as I know, is the longest, at 46 mins.

Without my listening to the whole podcast again, on his point of non-contradiction, he said that Hegel was possibly the only Western philosopher who addressed this. In the Encyclopaedia Logic Hegel wrote ‘Contradiction is the very moving principle of the world.’ Do you deny that Plotinus did not recognise this - and the place of the ineffable (which Priest also expressed interest in), and that such recognition runs right through the work-in-progress that was Neoplatonism? Plotinus wrote:

‘What, then, is Philosophy?

Philosophy is the supremely precious.

Is Dialectic, then, the same as Philosophy?

It is the precious part of Philosophy. We must not think of it as the mere tool of the metaphysician: Dialectic does not consist of bare theories and rules: it deals with verities…Dialectic…has no knowledge of propositions - collections of words - but it knows the truth and, in that knowledge, knows what the schools call their propositions…it leaves petty precisions of process to what other science may care for such exercises.’ 

Enneads I.3.5

Each hypostasis negates (the process of contradiction) the one that precedes it - both in outflow and return. This focus on contradiction, negation and ineffability runs right through Neoplatonism and both are in Hegel - regarding the latter, I refer you to the closing lines of Hegel's poetry in the Phenomenology. Also Magee wrote well of Hegel's mytho-poesis.

You wrote ‘(The Neoplatonists) might engage in certain paradoxical formulations but that is rather different than what we are talking about here where you develop (quasi-) formal systems of reasoning that depart from the PNC.’ The Enneads, however unsystematically presented, are not concerned with mere ‘paradoxical formulations’, rather, the development of a system of reasoning structured on outflow and return. Contradiction and the ineffable are fundamental to that.

I strongly state to you that my motive is not so much to get people interested in Cusanus as it is to bring out an immensely important current in Western philosophy that has been drawn upon over and again in all areas of Western culture from science (Kepler) to art (Picasso) even as it has been suppressed and denied (particularly by Western academic philosophers) - Hegel the Western supremacist (if you want any clear quotes from his writing to support this I can provide them) being just one example. The ‘reason’ of Plotinus becomes the ‘scientific’, conceptual ‘reason’ of the master race.

Why has this current been treated this way? Even in its idealist form, the message is clear - nothing lasts but change. Philosophy in the West is not merely practised in a pleasant vacuum but in societies dominated by the bourgeoisie with their ideology (a system of belief delimited by interests). Arguments have real consequences.

Marx and Engels, in standing this current upright, brought out its revolutionary core - my 'days are numbered', your 'days are numbered' as are those of the bourgeoisie and their domination. Capitalism will pass, and nothing can stop that. All that exists is the (theoretical) absolute of change. Not reassuring words for wood-panelled rooms and discussions of the learned.

Marx on Hegel put it excellently:

‘I therefore openly avowed myself the pupil of that mighty thinker…The mystification which the dialectic suffers in Hegel’s hands by no means prevents him from being the first to present its general forms of motion in a comprehensive and conscious manner. With him it is standing on its head. It must be inverted, in order to discover the rational kernel within the mystical shell.

In its mystified form, the dialectic became the fashion in Germany, because it seemed to transfigure and glorify what exists. In its rational form it is a scandal and an abomination to the bourgeoisie and its doctrinaire spokesmen, because it includes in its positive understanding of what exists a simultaneous recognition of its negation, its inevitable destruction; because it regards every historically developed form as being in a fluid state, in motion, and therefore grasps its transient aspect as well; and because it does not let itself be impressed by anything, being in its very essence critical and revolutionary.’

Capital, vol. 1, Postface to the Second Edition 1873

I am interested neither in seducing (?) nor scolding but in honesty and the truth. A philosophy academic was asked on ‘The Philosopher’s Zone’ ‘What is philosophy?’ He gave an excellent reply: ‘The posing of the most disruptive questions.’ There will never be an end to the need for philosophy.

Jim Young on 11 December 2017

On Contradicition

Graham Priest's mention of Aristotle's weak proofs for the principle of non-contradiction reminds me of Ortega y Gasset's delightful discussion of this in The Idea of Principle in Leibniz. This leads me to wonder if Ortega is on the menu?  

Robert Jackson on 11 December 2017

Pure dynamite- Part 1

I cannot thank you enough for this podcast.   Since my retirement about 3 years ago,  for reasons too complex for a comment, I have been studying the history of philosophy in depth (an average of 40 hours a week).  I have used a variety of sources, including your podcast ( which I discovered about 18 months ago via a footnote on a paper I read on the Stanford Philosophy website).  I have listened to literally hundreds of online video/audio presentations on philosophy (I have completed my personal history of Western Philosophy (undoubtedly with gaps) from Thales through Fichte/Schilling/Schleiermacher/Herder and am now working on Hegel), including all of your prior podcasts; and this podcast is, for me, by far the best presentation I have heard.  It is wonderful.  A true gift for Christmas!   I have one favor to ask:  can you give me any references to Professor Priest's assertion that logic is dependent on the underlying metaphyic (or faith) of the person applying the logic.   I personally agree with the insight, but I have not found many authorities who agree.  Again, my thanks.   


In reply to by Robert Jackson

Peter Adamson on 17 December 2017


Thanks, I'm glad the podcast has been useful in your admirable self-education in philosophy! That's really brilliant that you are doing that, I can't imagine a better use of one's retirement years - but then I would say that, wouldn't I?

I am not sure if Priest has articulated that idea anywhere in writing, I thought it was more a general, off the cuff observation in the interview, but maybe others who know his work can steer us to a relevant passage.

Robert Jackson on 11 December 2017

Pure dynamite- Part 2

To make a short comment on Graham Priest's comments on Hegel and the PNC,  I found his analysis "spot on."   As I interpret Hegel (consistent with the view of Professor Arthur Holmes of Wheaton College as set out on his online video discussing Hegel), Hegel's did not reject the PNC, he simply found it limited in application and  irrelevant for his analysis.  Hegel sets out his position, in part, in Section 39 of the Preface to the Phenomenology.  As I  interpret Hegel,  the PNC certainly is applicable in the correct contexts, but that context does not include the world of intellectual forms (for which forms, Hegel has several names).  And, I think Hegel, for the most part, is correct on this point.   Where I totally disagree with Hegel is on his dialect and his view of what I call the "progressive teleological obsolescence" view of philosophy of history as applied to the world of ideas.   On this issue, I find Vico's view of the circularity of ideas to be much more accurate and persuasive.  

Noctua on 14 December 2017

On Contradiction

Yes, that would be delightful - hopefully as a main course. There seems to exist a lifelong Heraclitan dynamic between the hand we're dealt and the way we choose to play it that reveals itself as we navigate the dialetheism inherent in becoming. It's interesting to consider, in light of Ortega y Gasset's thinking, how things might have turned out differently for Socrates had his "circunstancias" been different. Perhaps, had the powers that were been better able to tolerate contradiction, to envision truth as less static and absolute, Socrates might have been presented with more favorable options in the end. I believe it was Nobel physicist Max Born who said, "For the belief in a single truth and in being the possessor thereof is the root cause of all evil in the world."

Otmar on 16 January 2018

Logic, Determinism and Quantum Theory

Hi Peter,

Since Graham Priest ventured fast paced through much of modern western philosophy on logic, I was surprised that two things did not appear in this interview: Determinism and Quantum Theory. I know, 30 Minutes is a very short time, and all the content has been intriguing, but here is why determinism and quantum theory was constantly on my mind after 10 minutes into the interview: I think the notion of determinism is very much connected to the idea of a true/false logic. This expresses itself in the common sense assumption, that if we were able to measure everything, we could predict everything. We just don't have the right tools (yet). Hence everything is determined in the first place. Physics has posed a huge challenge to that assumption with the development of quantum theory. Here we have quantum particles which are in two states at the same time (or none, depending on how you view it), called superposition. Only when realized, these particles possess exactly one state. No measurement could determine the state of the particle beforehand, because nothing exists beforehand which could be measured.

The notion of the true/false logic was (and still is) so ingrained in western thought that Albert Einstein came up with the "ingenious" argument rejecting quantum theory,: "God does not play dice with the universe".

Now, pitting classical logic and Nargarjunas logic against each other, it seems to me that Nagarjunas four possible states actually fit quantum theory better than a mere true/false logic. This again could tell us something about determinism, whether Nagarjuna, or the Buddhists, or Jains in general, are determinists. My guess would be that they have a much easier time accepting non-determinism than a staunch classical logician. That said, Nagarjuna and his contemporaries might have had a much easier time to accept quantum theory than us, because we are stuck in common sense logic with only two valid options.

In my own discipline, International Relations (which is a social science), a contemporary scholar, Alexander Wendt, complained that all of the social sciences are based on classical physics, which is epistemologically and ontologically based on classical logic. He wrote a whole book on how he thinks that all social inquiry should not be based on classical physics, but rather on quantum physics with its non-determined states. After listening to the podcast, I think Alexander Wendt should have looked East as well to enrich his critique of contemporary social sciences. Here also, I think we could learn a lot from other traditions as your interview with Graham has nicely exemplified.

So, in the end, I am wondering if you, Peter, (or any of the readers of this comment) think that my comment has any merit. I am not trained in physics (merely some engineering) so I might be completely wrong footed here. If there is a physicist out there who can correct or enhance my statement above, I would be grateful.

If you have read up to this point, I want to thank you for the podcast series. I think there is no other more accessible entrance into philosophy than your podcast. It has opened my eyes and given me the ability to actually participate in philosophy.

On this note, I was wondering if the books of this series ever get translated into German. For my generation (I am 32), it is very common to speak English, but for my parents generation this is not the case. If you want even more people having easy access to philosophy, please consider translating your books. I would buy all of them!

Keep up the good work!

Otmar (Augsburg, Germany)

In reply to by Otmar

Peter Adamson on 16 January 2018

Quantum mechanics

I really don't know much about quantum mechanics but my guess is that it gives us situations where there is no truth value, but not that both truth values are satisfied, for instance for a given particle it could be that it is neither moving at a certain speed, nor not moving at that speed, but not both moving and not moving at that speed. So I think you would not get the tetralemma, quite, but only three of the four - this leaving aside the question of whether what quantum mechanics says is that the speed or whatever really is indeterminate or simply not determinable by us. As I say though, this is well out of my comfort zone!

Re. a German translation yes, I would love for that to happen, it is not planned yet but I would like to get a German publisher interested and may try to do so.


Martin on 4 May 2024


One could probably add Plato's discussion of the problem of his theory of forms in the Parmenides as another case in the western tradition where 'non-classical' logical ideas are considered as being part of possible solutions.

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