© Graham Priest and Figure/Ground

Dr. Priest was interviewed by Laureano Ralón. January 1st, 2018.

Graham Priest (born 1948) is Distinguished Professor of Philosophy at the CUNY Graduate Center, as well as a regular visitor at the University of Melbourne where he was Boyce Gibson Professor of Philosophy and also at the University of St Andrews. He is known for his defence of dialetheism, his in-depth analyses of the logical paradoxes (holding the thesis that there is a uniform treatment for many well-known paradoxes, such as the semantic, set-theoretic and Liar paradoxes), and his many writings related to paraconsistent and other non-classical logics. He is the author of numerous books, and has published articles in nearly every major philosophical and logical journal. He was a frequent collaborator with the late Richard Sylvan, a fellow proponent of dialetheism and paraconsistent logic.

What attracted you to philosophy and how did it shape your view of the world?

That’s kind of complex, but let me keep it simple. I was trained as a mathematician, but by the time I finished my doctorate, I knew that philosophy was much more stimulating and fun (for me). This was so for (at least) two reasons. First, mathematics is pretty cut and dried: either your proof works of it doesn’t; there’s not much to argue about. By contrast, any interesting philosophical view is bound to be contentious, and intelligent people can disagree about it. I love trying to figure out what I think, and I also love the back and forth of philosophical debate that this involves. Secondly, many philosophical issues are pretty esoteric. I have done my share of engaging with these—maybe that’s the mathematician in me. But many philosophical questions are important and meaningful to everyone: Is there a god? Should I give money to those suffering in other countries? Should I vote for a government which spends money invading other countries without just cause? Everyone, whether or not they are a philosopher, has views on these matters. I love being able to talk to people about these issues. Of course, philosophers think more carefully and systematically about these matters than do most people. So they have a responsibility to inject clarity and thoughtfulness into public debates about them.

How did philosophy shape my view of the world? In some very concrete ways. I was brought up as a Christian. I ceased to be so when I started thinking philosophically about the matter. The views just did not survive rational reflection. Much later in life I became acquainted with Buddhist philosophy. I’m not a Buddhist, but I think that the metaphysical and ethical views of Buddhism stand up to scrutiny much better than the philosophical views of most religions that I know. Much more generally, though: our views on most important matters are determined simply by the contingency of where and when we are born. That’s not a good basis on which to believe anything. One needs to think through these things carefully and philosophically, and try to figure out what is the best thing to believe. I think that that’s the most important thing that a training in philosophy can give to anyone.

Who were some of your mentors in graduate school and what did you learn from them?

Let me step back a bit. I studied mathematics at Cambridge. The lecturers were pretty atrocious. They would come in and write on the board, and just expect you to write down what they wrote. (I hope that the standards of pedagogy have gone up there now!) In my last year I studied logic in the Philosophy Tripos. I had two supervisors, for whom I had to write an essay every week. I would then meet them to discuss what I had written. One of these was Hugh Mellor. He didn’t pull his punches. I guess this taught me how to stand up for myself in philosophical debate. The other was Sue Haack. She was writing her doctorate at the time. The thesis was to become her book Deviant Logic. Thus, it was she who generated my interest in non-classical logic, which I have had ever since.

When I left Cambridge I moved to London to do an MSc in mathematics. I had a number of lecturers, but the two most impressive were John Bell and Moshe Machover, neither of whom was much older than I was. They were gifted teachers. They were clear; they had a way of cutting to the essence of things; they gave out excellent lecture notes; and above all, they had an infectious enthusiasm—which often continued at the pub afterwards. I guess they showed me what a good lecturer was. After that, John became my PhD supervisor. I don’t think I learned a lot from him formally after that—which is not to say that he was not there if I needed him: he was. But he very much let me go my own way and follow my own interests, which I appreciated very much. When I supervise PhD students now, I never try to get them to work on particular topics—ones that might interest me—I’m happy to support them in wherever they want to go.

What advice would you give to young graduate students and aspiring university professors?

That’s a hard issue. Perhaps the most important thing is that one must have a plan B. Academic jobs in philosophy are very hard to get. And even if you are determined to get one, you must be prepared for the possibility that you will have to go some other way. The best, maybe the only good, reason to do a PhD in philosophy is that you love what you are doing. So, even if you don’t become an academic, you will have spent a number of years doing something that is personally very rewarding. What else? The major thing that will get you a job in philosophy is how good the philosophy you produce is. How will you write the best philosophy? By following your burning interests. I see so many PhD students who don’t really know what to write about. They find a topic they think they can write on during their coursework, and then they work on the minutiae of that. They end up writing a very “professional” piece of philosophy, but not a very inspired piece. Think big.

You were recently invited by Markus Gabriel to give a talk on the topic of “everything and nothing” at the University of Bonn, where you stated that “metaphysics had a hard period during the XX, but it’s back in fashion now”. Of course, our readers are familiar with the way anti-metaphysical sentiments (from Husserl to Derrida) run deep through most part of XX century continental Philosophy. But perhaps you might enlighten us in briefly describing how this played out in the Anglo-American tradition…

The anti-metaphysical influences on American philosophy in the 20th century, were two. The first of these, ironically enough, was European, namely the logical positivism that appeared in the Vienna Circle. This espoused a certain kind of verificationism. The second influence was the American Pragmatist philosophy of Peirce, James, and Dewey. For these philosophers, truth was, again, some kind of verification. The two traditions met in the United States in the 1940s. Many of the Vienna Circle philosophers were either Jewish or left wing, and so they had to flee Nazism. Many, such as Carnap and Feigl went to the US. There, their positivism merged with the native pragmatism to produce philosophers such as Quine and Sellars. Quine and Sellars were no verificationists. However, they absorbed the positivists’ view of the centrality of science to understanding the world. This meant that they were naturalists. Science was at the core of human knowledge. All other forms of knowledge had to be shaped to fit in with this. The influence of the Vienna Circle was brought to the UK by Ayer. This did not immediately result in the same kind of naturalism. That had to wait until the impact of Quine on the UK in the 1960s. What it did produce was the expressivist ethics of thinkers such as Hare. Ethical claims could not be verified, and so had to be thought of as mere expressions of emotion. Verificationist and pragmatist thinking has never disappeared entirely from Anglo-American philosophy, though in the last 40 years quite different metaphysical realist views have become prominent, some of these coming from Australian philosophers such as Armstrong. In the first half of the century, Australia was relatively isolated from Northern Hemispherical philosophical events, and so the things which shaped Anglo philosophy in the Northern Hemisphere had much less impact there.

In A Thing of this World (2007), Lee Braver identifies anti-realism as the defining characteristic of continental philosophy from Kant to Derrida. His central thesis is that the history of modern (and postmodern) philosophy can be interpreted as taking an ever greater distance from Descartes’ original metaphysical position (i.e., classical realism). However, some commentators today speak of a “realist turn” in continental philosophy beginning roughly in the first decade of the 2000s. Markus Gabriel’s “new realism” is a clear exponent of that turn, but there are other developments as well, such as network, process or relational philosophies that borrow inspiration from Alfred North Whitehead – a philosopher of science turned metaphysician. I wonder if you think this “realist turn” has facilitated dialogue across traditions, and in particular, what you make of Whitehead’s philosophical legacy, which emerged almost in perfect isolation and against the background of a profoundly anti-metaphysical century…

Well, anti-realism is certainly a feature of much so called “continental philosophy”, though by no means all of it. It is no part of Marx or the 20th century thinkers influenced by him, such as Althusser and (the later) Sartre, for example. I also agree that thinkers like Gabriel and Meillassoux see themselves as consciously reacting against this anti-realism. In fact it has always surprised me the so called new realism rarely alludes to the fact that so-called “analytic philosophers” reacted against this anti-realism much earlier. In fact, the standard historiography has this occurring in the early years of the 20th century, when Russell and Moore rejected the influence of Kant and Hegel. And there has continued to be a strong theme of realism in analytic philosophy throughout the 20th century, whether this be (the early) Wittgenstein, Gödel, Quine, Kripke. The philosophical writings of Whitehead, Russell’s coauthor of Principia Mathematica, have had, as far as I can see, little influence on either analytic or continental philosophy. In terms of their content, beyond the fact that they espouse an ontology of events, I must confess that I can say very little, since he is one of the many philosophers I have never read. I do think, though, that the boundary between analytic and continental philosophy is breaking down. A number of European thinkers are turning to Wittgenstein and Kripke. And a number of Anglo thinkers are turning to Hegel and Heidegger. In truth, I think that the difference between these two “traditions” is something of a beat-up, driven by stylistic differences and turf wars. For all the differences, many of the problems that philosophers from the two traditions have been focused on are essentially the same. (I have discussed the matter in my ‘Where is Philosophy at the Start of the Twenty First century?’, Proceedings of the Aristotelian Society 103 (2003), 85-96.)

What’s your take on Markus Gabriel’s fields-of-sense ontology?

I’m very sympathetic to the idea that everything is what it is by being in a network (field, if you like) in which it relates to other things. That’s very similar to Markus’ view, I think—though I am coming at it from Mahayana Buddhist views concerning emptiness. There is one important difference between us here, though. Markus takes these fields to be local: there are many relatively autonomous fields. I think that in the last instance there is one single field. This is essentially the Chinese Huayan Buddhist version of the Indian view. (All these things are explained in Part 3 of my book One (OUP, 2014).) Another difference between us is that Markus holds that there is no world, i.e., no sum of everything. I think there is: it is simply the mereological whole comprising all objects (as I explained in the Bonn lecture). Essentially, Markus infers his view (though not explicitly) from the claim that the proper parthood relation cannot be antisymmetric. I think it can be.

During your lecture at Bonn you brought in Heidegger at different junctures to illustrate how his thinking about nothing comes suggestively close to your own discoveries. In continental parlance, perhaps one way of expressing your position about nothing is to think it as an unstable fusion of the nothing (Heidegger) and nothingness (Hegel), which combined would constitute the inherently contradictory foundation of all reality. Is this an accurate depiction of your position?

Nothingness is the absence of all things. I don’t think that that’s terribly contentious if you think you can discuss nothingness in any sensible way at all. But it does follow that nothingness is a contradictory thing. It is, after all, a thing. You can think about it. (You just have.) But it is also the absence of all things, and so not a thing. I think that nothingness can be defined as the mereological sum of no things: that is, what you get when you put no things together. Again, that seems to me to be very natural. In the Bonn lecture I argued that this contradictory object was the ground of reality, in the sense that any object depends for being what it is—viz, an object—on not being nothingness. If you like, to be a presence, it must be an absence of absence. Now, how does this relate to Heidegger and Hegel? It is actually very similar to Heidegger’s view. Heidegger argues that nothingness and being are the same (though, I don’t follow him down that path). And he is pretty explicit, right from the start, that being is the ground of reality (beings). Moreover, in the Beiträge he is pretty explicit that being is a contradictory thing. Hegel is rather different. For him, nothingness is a concept, non-being—the second concept in the Logic. (Though because of Hegel’s idealism, the difference between a concept and the things that fall under it is not always so clear. I don’t follow him down that path.) And he famously argues that it is identical with the first concept, (pure) being. In that way, he is similar to Heidegger. I don’t know of anywhere in Hegel that he suggests that this is the ground of reality, however. If anything, it is Geist in the form of the absolute—or if you like, the absolute idea (the last category in the Logic) which is the ground of reality.

I’m curious about your own position with regards to Heidegger and Hegel and the way they are being appropriated by the Anglo-American philosophy?

Philosophy (East and West) has produced many great philosophers. Hegel and Heidegger are certainly two of them. Great philosophers have a way of making a view that seems pretty crazy enticing. Perhaps no great philosopher has ever espoused a view which can stand up to indefinite philosophical scrutiny; but there will always be much to be learned from such philosophers, since their work, right or wrong, contains profound points of insight and understanding, points which can flourish in new philosophical surroundings. I don’t think that it is controversial to say that Anglo philosophers did not read and think about the work of Hegel and Heidegger for most of the 20th century. But good philosophy has a habit of breaking through parochialism. So it’s hardly surprising that we are now seeing Anglo philosophers working with Hegel and Heidegger (e.g., Brandom, Dreyfus, Garfield, Moore). Neither is this traffic one-way. I have many friends in Germany and Italy who are as familiar with Hume and Wittgenstein as they are with Hegel and Heidegger. Let me also note, though you did not ask about it, that this is not the only barrier which is now being broken down. That between Eastern and Western philosophy, a much more impenetrable barrier than that between Anglo and Continental philosophy, is also starting to crumble. I have many friends, both Eastern and Western, who cross that barrier.

Returning to the earlier question about nothingness, I wonder if the notion of nothing as simultaneously being a mereological sum (the sum of everything which is not an object) and the ineffable (the absence of all things) can lead to a more positive, affirmative and even productive characterization of it. As a matter of fact, a number of scholars associated with the “realist turn” have read your notion of contradiction along deleuzian lines, i.e., as suggesting an unstable foundation that’s responsible for an ontogenesis of the real. Is your notion of contradiction (and nothingness) simply a logical derivation, or do you see further metaphysical/ontological ramifications to your discovery…

I’m not familiar with the work you mention, so I can’t really comment on it. All I can say is that once the tools and ideas are out there (be they phenomenology, sense and reference, language games, deconstruction, dialetheism), people will make all kinds of uses of them. How good those uses are, continuing philosophical scrutiny will tell. As to your last question, I often use the tools of formal logic in my work. I find them very helpful in shaping my philosophical thinking. However, formal logic is but a tool—albeit a very powerful and fecund one. And the value of any tool is in what you can do with it. I don’t expect logic to be very helpful for hammering in nails; but I do expect it to be so in profound questions of philosophy. And that is a view as ancient as philosophy itself, both East and West.

Yet much of the (neo)pragmatist tradition in the United States, fueled in part by the appropriation of Heidegger we mentioned earlier, has come to think of logic and hammers as closely related. Normative pragmatism, in particular, regards conceptual work (i.e., the implicit revision of concepts) as inseparable from our “everyday skillful coping”. I wonder how you conceive of this relation between theory and praxis in general and the pragmatist reading of Heidegger in particular. Is there a difference to be made, perhaps, between normative pragmatism and normative pragmatism?

Human skills are many: hammering in a nail, changing a tyre, giving an after-dinner speech, proving mathematical theorems, speaking Chinese. Some of these are more cerebral, and some are more physical, though most have some of each of these elements, and all are embedded in a form of life, as Wittgenstein put it in the Investigations. Clearly, being able to reason well, solve difficult intellectual problems, invent new concepts, are also skills. So hammering and reasoning have at least that much in common. (There are, of course, many differences, too obvious to mention.) Norms are a different matter again. Norms can be thought of in many ways, but most obviously, they are guides to action. Certainly, skills can be exercised by following norms. But equally, one can know the norms, and yet be inept and unable to follow them. And certain skills can actually be about breaking norms. (Think of great innovations in art, music, and even philosophy.)

I guess it could also be argued –as you seem to imply– that praxis becomes sloppy without precise conceptual work. Indeed, there is a strong tendency among recent certain neo-realist thinkers to claim that what we need is not less, but more conceptualization…

The relationship between skills and concepts is a multi-faceted one, and is unlikely to be captured by a simple slogan. For a start, some skills are acquired, at least initially, by learning the appropriate concepts, and their associated bank or rules. Think of how one normally learns chess. (This is a bishop. It can move along a diagonal, but cannot jump over pieces.) On the other hand, a native language is normally learned in a completely non-conceptual way. Thus, normal native speakers may well have no explicit understanding of the grammatical concepts of their language and their associated bank of rules. However, it is often the case that a skill can be improved by an explicit mastery of concepts. Thus, a person’s ability to communicate is most surely likely to be improved by an understanding of grammar. And someone’s mathematical ability is unlikely ever to amount to anything much until they have mastered a lot of conceptual skills concerning proof. (I’m not talking about the skills of counting and measuring. I’m talking about the skills of professional mathematics.) On the other hand, many very notable skills can be exercised only if what is done is completely unconceptualised. One will never be a great jazz saxophonist, martial artist, or racing driver if one has to stop and think. One has to be in the moment (“in the zone”). As for philosophy, there are some philosophers who have thought that theorisation, and so the conceptualisation involved in this, is pernicious. This was Wittgenstein’s official view in the Investigations—not that he always adhered to this in the text. I think that such a view is just crazy. You are never going to be good physicist, mathematician, economist, without a heavy dose of conceptual expertise. It’s selling philosophy short to suppose that it could be different.

Let’s get a little more technical as concerns your own contributions to logic. Simply put, the philosophical school of dialetheism, of which you are the most prominent representative, asserts that true contradictions exist in reality, a position commits you to paraconsistent logic, on pain of otherwise embracing “trivialism”, i.e., accepting that all contradictions (and equivalently all statements) are true. (To put things in the context of our previous discussion, it would seem that your position within the wider scope of paraconsistent logic is much more compatible with a neo-realist position associated with ontological pluralism than with the idealist/subjectivist position associated postmodern pluralism). That said, there are competing theories which within paraconsistent logic that do not commit to either the existence of true contradictions, opting instead for a weaker standard of empirical adequacy. Why is empirical adequacy not sufficient, in your view?

Let’s get a few things straight for a start. A dialetheia is a pair of statements of the form A and ~A (it’s not the case that A) which are both true. Dialetheism is the view that there are some such pairs. Explosion is the principle of inference that everything follows from a contradictory pair of statements (i.e., a pair of the form A and ~A). A paraconsistent logic is one which denies the validity of Explosion. A dialetheist had better hold that the correct account of validity is paraconsistent, or they are committed to the truth of every statement—trivialism: a very extreme form of dialetheism, and a very unattractive one. On the other hand, one can subscribe to the correctness of paraconsistent logic without being a dialetheist. (In fact, most paraconsistent logicians are not dialetheists.) One might, for example, think that, whether we like it or not, we may well be stuck with inconsistent information, and one does not want to infer really stupid and irrelevant conclusions from this. Or one might have an inconsistent theory, and be quite happy if its empirical consequences are “adequate”—whatever that means. As to dialetheism, it commits one to no particular view about truth. One can hold that truth is correspondence to a fact, in which case dialetheism implies that reality contains contradictory facts. Or one might be a verificationist about truth. Dialetheism will then imply that some contradictions are verifiable. So dialetheism is compatible with forms of realism and forms of idealism. As to the question of whether there are contradictions in reality, it is not clear that this even makes sense. If reality is constituted by chairs and stars, mountains and mole-hills, these are not the kind of thing that are true or false. To claim that they are so, is simply a category mistake. I think that when the question of contradiction in reality is raised, what is usually at issue is simply whether there can be dialetheias, A and ~A, which describe some non-mental state of affairs. Note that this is quite different from someone thinking/believing that A and thinking believing that ~A. That is not even a dialetheia, merely a contradiction in someone’s thought. (Compare the pair ‘x believes that A’ and ‘x believes that ~A’ with ‘x believes that A’ and ‘it is not the case that x believes that A’.)

Clearly, logical forms and operations may possess objectivity but lack objecthood. Now, perhaps the tendency to think of contradiction as truly existing in reality derives from a certain “ontological liberalism” (some call it “flat ontology”) whereby everything seems to qualify as an object?

Well, I do think that everything is an object—everything you can refer to, think about, quantify over. I don’t think that that necessarily leads in the direction of dialetheism, though. This can be delivered only by what one takes the properties of those objects to be. To give one very simple example: Consider the Russell set; that is, the collection of all sets that are not members of themselves. This is the object behind Russell’s paradox. One way to avoid the paradox is indeed to insist that it does not exist: there is no such object. But another way to avoid the paradox is to suppose that it does exist, but that is “too large” to be a member of anything. Everything, then, depends on what properties you take the set to have.

How do you understand the relation between paraconsistency and paracompleteness? Do you think there are local forms of consistency/completeness, and do you think they’re related?*

Paraconsistency I defined in answer to Question 12. Paracompleteness is its “dual”. Implosion is the principle of inference that, for any A, Av~A follows from anything. A logic is paracomplete if it does not validate Implosion. Paraconsistency and paracompleteness are quite independent. There are logics that are paraconsistent but not paracomplete, vice versa, both, and neither. Whether either Explosion of Implosion should be taken as a valid logical principle is still a very contentious matter amongst logicians. For what it is worth, I have always rejected Explosion, but endorsed Implosion.

So far, that makes dialetheias sound very “static”. Do you think that they have a dynamic element, something that one might call a generating power?

There’s nothing dynamic or generative about a dialetheia as such. The liar sentence, for example, is true and false, and that’s that. Of course, some people have made dialetheias the cornerstone of a dynamic process. The obvious example is Hegel. In the dialalectical progression of the Logic, a concept and its negation can both apply to an object. This generates a new concept. The contradiction is aufgehoben. But that doesn’t mean that it has disappeared, simply that it has generated a more complex concept, more adequate for grasping reality. (And of course, because of Hegel’s idealism, this conceptual development is mirrored in a development is the social and natural worlds.)

The matter is different again with respect to certain theories which take there to be a ground for reality, which in some sense gives rise to the rest of it. Thus, for example we have the One of Neoplatonism, the Dao of Daoism, and Heidegger’s Being. In each of these cases, it turns out that the ground is contradictory; it is ineffable, though effable as well, since people manage to speak about it. I don’t think that it would be true to say that the ground is generative because it is contradictory. Rather, its ineffability is essential to its generative power. (It can’t be any thing, because it gives rise to all things.) And it is this ineffability which also gives rise to its contradictory nature. So both the generative ability and the contradiction arise from something more fundamental. Now, I can’t say that I subscribe to any of the theories I mentioned. But in the Bonn lecture I did argue that nothingness is exactly such a contradictory ground of reality.

During this interview, we spoke of a contemporary “realist turn” and you expressed sympathy with the idea that everything is what it is by being in a network in which it relates to other things. However, in addition to fields-of-sense ontology (Gabriel) and process philosophy (Whitehead), there are other forms of realism stemming from, say, Heidegger: such as Graham Harman and the notion of a real object that withdraws from all access, or Jean-Luc Marion and the notion of a “saturated phenomenon” or event which is not quite a thing-in-itself but hasn’t yet immaterialized into an object of experience. The list is not exhaustive, of course; but broadly construed, I suppose the realist turn of the 2000s amounts to an “ontological turn” which attempts to overcome a certain subjectivist bias associated with the philosophies of access. I wonder what your own brand of realism would look like. What does it mean to be a realist, really?

‘Isms’ in philosophy are thrown around all over the place. And I think that if you find someone using the word, the best thing to do is to ask them what they mean by it. To complicate matters, one can be a realist (or not) about many things: the past or future, abstract objects, numbers, societies and economies, the theoretical entities of science such as electrons and quarks. Roughly, I guess, to say that one is a realist about some kind of entity is to say that they exist, and are what they are, independently of any mind—though what that phrase means is itself highly ambiguous. I suppose that I’m a realist about some things in some senses. Thus, it seems to me that, as physics tell us, the physical cosmos would have evolved in much the same way, even had sentience never developed. In that sense, it’s not mind-dependent. On the other hand, how that world evolves can only be characterised in language, and so depends on the mental. (In One (13.5), I described my view as going between the horns of realism and idealism).



What are you currently working on?

As usual, I have a bunch of things on the go: papers on logic, metaphysics, the foundations of mathematics. I have a book in press with Oxford University Press called The Fifth Corner of Four. This is about Buddhist metaphysics and a logical principle called the catuṣkoṭi (pronounced chatushkoti), according to which things may be true, false, both, or neither. Buddhist metaphysics is not one thing. It evolves through various forms during the evolution of Buddhism and its various schools in India and China. The catuṣkoṭi plays a central role in this evolution, itself evolving in the process. The book tells the story, and shows how to make sense of some of the crucial moves in the development using the techniques of contemporary logic.

I am also about to start to write the next book. This will be on political philosophy—a quite new development for me. The last two chapters of One (Oxford University Press, 2014), were on Buddhist ethics, and I started to wonder what the implications for political philosophy were—political philosophy has not played a large role in the history of Buddhist thinking. I’m not entirely sure where the book is going yet, but the current Dalai Lama is on record as saying that as far as political economy goes, he is a Marxist. I think he understands the implications of his Buddhist views exactly right.

*Question drafted by Peter Wolfendale

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