Carlo Rovelli takes aim at analytic philosophy's naive realism

With the release of his first book directly taking on philosophy, On the Equality of All Things, physicist Carlo Rovelli takes aim at analytic philosophy's return to realism. He argues that much of the philosophy of the twentieth century either hasn’t taken up the new sciences of Einstein and Bohr, or is too trapped focusing on how mind, spirit, or consciousness is special. In this interview with the IAI's Ozbir Kip, Rovelli argues that electrons and minds, stones and laws, judgments and galaxies, are not fundamentally different in nature from one another. He goes onto argue, neither science nor philosophy, will ever be able to get at ultimate reality.

Kip: You're a theoretical physicist who is also a philosopher, which is a rare attribute to see in a lot of physicists. What first got you into philosophy?

Rovelli: I have been interested in philosophy since I was young. Maybe today it is not too common to see scientists interested in philosophy, but certainly it was not so in the past. Think about the greatest, like Einstein, Maxwell, Boltzmann, or Newton, or - to get out of physics - Darwin: they were all deeply interested in philosophy. There have always been some scientists totally uninterested in philosophy, or even coming out with strongly disparaging comments on philosophy, like Stephen Hawking, who said philosophy is dead because now we have science. But I think that’s plain nonsense.

The reason so many scientists are interested in philosophy is that there is an actual dialogue between science and philosophy which is a constitutive part of both science and philosophy. From the science side, philosophy becomes relevant when the rules of the game and the conceptual scheme in which you’re working are not clear. Science is also finding new ways for thinking about reality on the basis of the information we have, new data, measurements, new ideas, whatever—and that’s also philosophical work. So the scientists that say philosophy has nothing to do with their science—actually they are just in a certain philosophical position. They’ve learned a certain philosophy, and they’re stuck there. Kant is almost the prototypical philosopher, right? What was Kant doing? To a large extent, Kant was trying to make sense of Newton. There is this fabulous thing that is Newtonian mechanics—it seems to be explaining the world. How can it make sense? What is the space that Newton is talking about? I work in this interface as a scientist. Quantum gravity, which is my own science, is particularly close to philosophical questions.

An important question in the philosophy of science is the question of realism versus anti-realism. So you have people like Bas van Fraassen claiming that things like electrons aren't real, whereas you have people like Stathis Psillos who think they are, and you have structural realists somewhere in the middle. How would you characterise your philosophical position on this debate?

I think it’s a badly posed question whether an electron is real or not, because it takes for granted a clear understanding of what is to be real, which is not an a priori given. It’s part of the discussion itself. Some of the arguments of the anti-realists are very good, and I see that some of the arguments of the realists are very good, and when I read them carefully, I ask: where are they actually disagreeing? They disagree about a question that, in my opinion, has no meaning; it is only terminology

I find that the actual debate is shallow. Is an electron is real or not? A wave function is it real or not? A quark is it real or not? These questions assume that a solution to the larger debate about realism has already been chosen. The the larger debate is about all things: Is a chair real? Is my glass real? What do I know about the glass besides just the perception I have, the interaction I have with it? I love van Fraassen, he’s a fabulous thinker. But questioning the reality of the electrons and not questioning the reality of the glass, in my opinion, is just shallowness. The arguments we have for the glass being real are exactly the arguments we have for the electron being real, and the arguments we have for the electron not being real are exactly the arguments for the glass not being real of the kind that Hume considered.

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Reality is a parade of appearances, and there is nothing wrong with that.

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Did a prince, saying “to be or not to be” and wondering about vegeance, exist? Some say yes, of course, he exists. It’s Hamlet, everybody knows that. But you can also answer: no, that prince didn’t exist. It’s a fabrication by Shakespeare. In the real Danish royal house, there never was a prince like that. Which of the answers are right? Well, they both are right—it’s just they used “exists” in different terms, in different senses.

Classical mechanics provided a strongly realist understanding of the world. If you study classical mechanics, you’re naturally led to think, okay, I got it, the world is just something out there with some particles bouncing around; that’s the real stuff. But that’s the science of the seventeenth century, not the science of today. The science of today doesn’t testify for a worldview like that—especially because of quantum mechanics. My latest book is a call to philosophers to say, come on, get out of the naive realism that you incorrectly identify with science.

Your new book covers Buddhist philosophy alongside modern physics. What connections do you see?

Physicists have always fished into philosophical ideas. Schrödinger, one of the founders of quantum mechanics, was inspired by Vedanta, Hindu thinking. Bohr was influenced by Kierkegaard. Hans Halvorson, a contemporary American philosopher, pointed this out, and he’s completely right. The point is that when you try to understand new phenomena, you need to get out of some mental habits, you need new ways of thinking things, so you fish around in universal culture, for what is available.

Within Buddhist philosophy there is a stream which is particularly grounded in the name of Nagarjuna. Nagarjuna is one of the greatest Buddhist philosophers— say the analogue of Plato in India. I read this book a few years ago, and I found it extremely interesting. One of the great ideas, which resonates particularly with Wittgenstein, is that asking certain kinds of foundational questions is meaningless. What is the foundation of everything? What is the basic substance of reality? What is the ultimate reality from which everything apparently comes out? The ground of everything is matter. The ground of everything is consciousness. The ground of everything is God. The ground of everything is language, because everything we say is language, so everything is in language. The ground of everything is language spoken by communities — a collective community of thinkers, epistemic communities that have knowledge. These are just some of the philosophical traditions in the West. The great intuition of Nagarjuna of Wittgenstein is that the question of what is the ground of everything is just a bad question. It doesn’t mean anything. The way Nagarjuna puts it is: forget about the ultimate reality—the reality is the parade of appearances, and there is nothing wrong with that.

Wittgenstein shows us repeatedly that in philosophy the questions we ask are meaningless. We know plenty of stuff about the electron. Is it real or not? It’s like it’s a question that hasn’t any meaning. AIt is real in some sense, and not in others. This is fundamental to understanding quantum mechanics. The world, I believe—we are now jumping into the domain of the way I view the world—the world is very well described by how things affect one another, not by how things are.

Does this imply that things have properties in themselves, or that they have properties only in relation to other things?

The main idea is that I believe a lot of modern physics, especially, dramatically, quantum mechanics, forces us to the idea that the world is not well described by monadic properties, but properties always have to be interpreted relationally—with respect to something else. Velocity is relational. Things don’t have a velocity by themselves. I have a velocity with respect to the train in which I am, with respect to the Earth, with respect to the Sun, with respect to the galaxy. What is my own velocity by myself? Zero.

Quantum mechanics is telling us that everything I say about, say, a pen—its position, its color, its weight, its everything—I’m talking about the way the pen relates to me. But careful, this might sound a lot like Husserl or Heidegger. I’m not talking about humans. I’m talking about nature. This pen has properties with respect to this other object. I’m talking about the structure of nature itself, nothing to do with my consciousness, my spirit, my perceptions.

So you don't believe there's a significant difference between objects in nature and persons - that we're all physical entities?

That’s exactly the right question to ask. The title of my book, On the Equality of All Things, is an answer to your question. There's no fundamental difference between natural objects and mental objects, between culture and nature, between living beings and dead beings, between men and women - this is the equality of all things.

I'm Spinozian in this. The world is one, it's not many. It's the same, we're part of the story, we're one of the elements of the story. Reality is a collection of appearances. Forget about the notion of ultimate reality. Physics, in a sense, is on the wrong track if the question is what is the ultimate story?  People think, "Oh, Carlo is looking for the ultimate story." I'm not looking for the ultimate story. And that's not the ultimate story - it's not more ultimate than the conversation we’re having now, or the importance of love. Everything is ultimate from its own perspective.

 In your book you discuss Princeton philosophers who adopt a staunchly realist metaphysics about both science and morality. Do you think this is a sort of residue from secularisation, following from the Enlightenment?

I think it’s more modern than that. There’s a big trend in the Enlightenment and in the scientific tradition which is empiricism, and empiricism is anti-realist in a sense. Think about Hume—Hume is an anti-realist in a sense. The current realism is younger, and a bit shallow in my opinion. I believe it’s a bit of a reaction to continental phenomenology and continental philosophy in general, more in the US than elsewhere. I was in the US in the nineties —I was at Yale for a while, and there was an infiltration of French thinking in philosophy that scared a lot of intellectuals—everything is convention, everything is relative, everything is historical—and it played very badly, in my opinion.

Some of the philosophers I met came out of that debate, and they come from that argument and say, “no, no, we want Truth to be True and Morality to be about the Good, and things have to be Absolute to be reliable, they cannot be relative.” I think they’re dead wrong, because to try to ground morality on something outside ourselves weakens it —this is factually false. The mistake is to think that either there is an absolute good out there independent of us, or everything is as well as it is, no good, no bad. But come on, we humans are not too stupid to have either this or that. We live in between. Moral values are strong — why? Because they allow us to not live in the jungle. We correctly condemn criminals and try to defend society—not because we believe in Truth independent of us, but because doing that is what made us what we are. Because of what we are, not because of something outside us.

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The human mind is not special. It's just one of the aspects of the world.

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The same mistake, in my opinion, is infecting analytic philosophy. Take the idea of ‘truthmakers’: why is the sentence "the pen is on the table” true? Because the pen is on the table. I think this is bullshit.  It is a tautology. We cannot jump out of the world, looking at the world from the outside and talk about the pen on the table without knowing if the pen is on the table "The pen is on the table" always means “as far as I know, the pen is on the table”.

We’re all children of the Enlightenment. But the Enlightenment also came with a mythology, a myth, that thanks to reason you could put yourself outside the world, look at the world, and understand it totally, clearly, and with certainty. I think science itself is telling us that this is a mythology. We are not outside the world—we’re inside the world. We do not look at things from the outside. We do not get to total clarity and certainty. We only have internal, perspectival descriptions.

 You mention a beautiful story about two Chinese philosophers by a pond full of fish. Can you tell us it, and why you find it so illustrative?

There’s a debate, very hot, on consciousness, and one of the starting points before Chalmers’s formulation of the “hard problem” is a famous paper by Nagel about what it’s like to be a bat, in which he argues that subjectivity is unreachable—whatever you do, you will never know what it’s like to be a bat. And there’s also, he points out, no way to be in your mind. So your subjectivity is completely screened out from me, therefore screened out from scientific investigation.

I think this is wrong.  First because even a stone cannot be entirely known: who can exactly know all the single positions of all the atoms of the stone? And second because of a reason that was clarified by a thinker in China two thousand years ago: the one from whom I've stolen the title of my book. In his book there's a short story: he and a friend of his, philosophers, are walking on a bridge in a little Chinese garden. They look down at fish swimming in the water, and the philosopher says, "Oh, these are happy fish swimming in this clear water." His friend says, "You cannot say that, because you're not a fish. You cannot know how a fish is happy or not happy." This is exactly the point of Nagel's.

But Zhuangzi replies: "I'm not a fish, but you're not me. How do you know that I don't know about the fish?" This is destabilising, because he's equating the difference between humans and fish to the difference between him and his friend. The friend bites the bullet: "Indeed, I don't know what you think". In doing that, he admitts that he could not know that the philosopher thought the fish were happy. And then the shocking conclusion, by Zhuangzi: "Wait a moment - you started by saying that you knew that I know something, and then you stated you cannot know that I know that. You're plainly contradicting yourself." Bingo. It totally destroys the objection. Why? Because if it was true that subjectivity is so unreachable, communication would not be possible. But communication is possible, because they're communicating.

I think the argument about the absolute irreducibility of subjectivity in Nagel is equally wrong. It's misleading. The human mind is not special. It's just one of the aspects of the world. It is knowable but not completely knowable, like everything else.

Carlo, thank you very much for this conversation.

This is a shortened and edited transcription of an interview for the Philosophy for Our Times podcast. The full conversation is being released in two parts, with this—the first half—published today, September 15th, and the second half to follow shortly after.

Carlo’s new book, On the Equality of All Things: Physics and Philosophy, is published by Scribner in the US and Allen Lane in the UK.