In our last conversation about consciousness, Riccardo Manzotti and I arrived at a crux. Having found both brain- and action-based explanations of conscious experience unconvincing, Riccardo set out a radical alternative: our experience of the world (light, color, sound, smell, touch) is not a “movie in the head” provided by our neurons, nor the interaction between our bodies and our environment, but nothing other than the object itself. When I see an apple in front of me, I am the apple. Every perception is nothing more, nothing less, than the object perceived, hence every experience requires an external object to which it corresponds.

To those of us used to supposing that our experience is locked inside our heads and that our minds begin and end with our bodies, this externalist approach initially seems completely unacceptable, even laughable. How can my consciousness be both physical and outside my body? How can a subject, I, be identical with a thing? And since my experience changes, but the object clearly doesn’t, how can the two be the same?

Yet, casting around, one finds corroboration in surprising places. “I am what is around me,” wrote Wallace Stevens in his poem “Theory.” “You are the music while the music lasts,” reflected T.S. Eliot in “The Dry Salvages.” “What are called outside and inside are one and the same,” wrote Samuel Beckett to Georges Duthuis. Virginia Woolf’s Mrs Dalloway is a constant elaboration of this intuition: “She waved her hand, going up Shaftesbury Avenue. She was all that.” Nor are artists alone in arriving at these reflections: “Nothing can represent a thing but that thing itself,” thought the philosopher Edwin Holt in 1914. Two thousand years before him, Aristotle claimed that “actual knowledge is identical with its object.”

Such fragments hardly amount to proof, or even a hypothesis. But they do suggest that to consider experience as one with the object experienced is not perhaps so counterintuitive after all. What we want to do today is flesh out what Riccardo calls the “Mind-Object Identity Theory” and confront some of these immediate objections.

—Tim Parks

This is the sixth in a series of conversations on consciousness between Riccardo Manzotti and Tim Parks.

Tim Parks: Riccardo, at the beginning of these dialogues it seemed that the principal focus of our enquiry was consciousness, our moment-by-moment experience of the world. But in seeking to explain that you have made a problem, even a mystery, of something we assumed was fairly simple: the objects we perceive, the things we experience. You tell me that when I see an apple, my visual experience of it is the apple. Hence the apple is me, or at least it is that part of my overall experience that is the apple. My body, with its sensory capacities, creates an opportunity for what is out there to be the way I see it, at which point the being is the seeing.

At the same time a dog looking at this very apple, or a bird, or just another person on the other side, sees something different. Yet each of them, you claim, when experiencing the apple is the apple. How can that be? And of course, if I move around the apple, or see it in a different light, my experience changes, so if I am identical with the object then presumably the object also changes with my experience. There is no stable apple. Have I understood? And if I have, what sense am I to make of this? Doesn’t science, and common sense, tell us that an apple is an apple is an apple? Can’t it be measured, photographed, analyzed in a hundred possible ways? Its physical properties don’t change, do they? It is what it is.

Riccardo Manzotti: Your objection is that the world appears to change while actually you feel sure it remains the same. Right?

Parks: My experience of the world is different from moment to moment depending on where I am, where I look, how the light is, etc., yet the world seems to remain reliably there and unchanged. So how can my changing experience be the stable object I see?

Manzotti: You realize, of course, that you’re simply restating the traditional appearance/reality conundrum that has plagued human understanding since Plato. The world appears to be one thing, but I know it’s another. Right? And we all know where that debate leads: appearances get relegated to an inner mental domain—these days the brain—while outside the world stays real and largely unknowable. What I’m asking you to do is set aside the idea that there are appearances on the one hand and real objects on the other. There are only objects. Real physical objects. Your experience is those objects. There is no appearance/reality dichotomy.

Parks: Of course it’s exciting making grand statements that dismantle thousands of years of philosophy, but that doesn’t answer the question: How is it, if my experience is identical with the object—say your famous apple—that I can see one apple and someone else a different one. If we were both “identical” with the apple, surely the experience would be the same and we would be identical with each other, which is clearly nonsense. We both look at the apple but that doesn’t mean I’m you. God forbid!

Manzotti: Ok, let’s go back in time and do some basic thinking. Until the seventeenth century scholars believed that when a body or object was in movement, its velocity was to be considered an absolute physical property. A cannon ball was either moving or still. How could it be otherwise? A flying bird is moving and a mountain is still. It’s a no-brainer. Then Galileo came along and showed them they were wrong. Velocity is relative. The mountain is still with respect to the surrounding landscape, but it is moving with respect to the moon or indeed with respect to the flying bird. Eventually it was established that any and every object has infinite velocities, each relative to some further object. Velocity is always relative velocity.

Parks: This seems elementary.

Manzotti: Well, velocity is physical, is it not? It is not notional, it is not just “in the head,” it is not subjective.

Parks: And so?

Manzotti: My point is that despite being physical, it can’t exist by itself. It requires a relation with another physical system. You can’t say, or at least not in scientific terms, that an object has this or that absolute speed; you need to say it has this speed relative to that object. So let me put it to you: What if all physical properties were like velocity? Not absolute, but relative to other objects. What I’m asking you to contemplate is the notion of relative existence.

Parks: So not only is the apple neither still nor moving except in relation to other things, now it doesn’t even exist except in relation. You’re going to have to work hard to convince me of this. In relation to what?

Manzotti: The temptation is to say, in relation to you or me, but in that case we’d be resurrecting an immaterial subject, an insubstantial self, and getting ourselves into all kinds of trouble. The apple is relative to another physical object or objects, in the same way the velocity of the mountain is relative to the flying bird. So, what object is the apple relative to? Many. If it’s a case of experience, a body. A human body. An animal. An insect. But an apple also exists in relation to the surface it lies on, a table maybe, or the tree it hangs from. Bodies are not metaphysically special. They are just objects, though very complex objects, in the sense that, through their sensory capacities, they bring into existence the world we are identical with, the sights, sounds, smells and so on that are our experience, are us.

Parks: Bring into existence! Surely an object exists regardless of the other objects or bodies around it.

Manzotti: A key is a key only relative to its lock. Relative to anything else it is just a piece of metal. A face is a face only when in relation to a healthy fusiform gyrus, that part of the brain we know is necessary for face recognition. The same physical stuff constitutes different objects, depending on the other objects it is in relation with. Just as it has different velocities relative to different objects. Existence of this or that object is physical yet relative!

Parks: Riccardo, the idea I’m getting is this: that you are working crazily hard to eliminate anything intermediate between the body and reality. You don’t want appearance, you don’t want representations, you don’t want images in the head. Only the things themselves. A universe of objects. So the experience has to be the object itself. But for that to happen the old, reliable reassuring object—the bed I find when I go to my bedroom, the milk carton I know will be there when I open the fridge—has to be broken up and relativized. However, I’m sure the question everybody out there wants to ask you is the same question people used to ask Bishop Berkeley, the guy who said the world was all ideas and the tree didn’t exist if no one was there to look at it: What the hell is your famous apple when it’s not relative to me?

Manzotti: Tim, please remember: the apple is not relative to you. The apple is relative to that object that happens to be your body. You are your experience, in this case the apple. But to address your objection: when you’re not around for the apple, there is, of course, something still there on the table. But it’s not the apple you are familiar with. It is what is there relative to the table, the room, the earth’s gravitational field, and so forth.

Parks: But how can there be a table if it needs my relative presence to be a table! Or no?

Manzotti: The table needs another object. At least one. After all, what would the velocity of an object be if there were no other objects around? A lonely atom in a void universe would have no velocity whatsoever. The table is surely something for the apple even when you are not there. Likewise, the apple is something for the table. But what they are relative to each other is not what they are relative to your body.

Let me put it another way: in the room we have a whirlwind of physical states. This whirlwind contains a lot more than a human being could ever perceive—atoms, neutrinos, photons, quarks, strings, quantum fields; a huge range of possibilities. When the body comes into the room, its sensory capacities carve out one possible subset of that whirlwind. Or, looked at the other way round, one possible set within the whirlwind finds, relative to the body, a suitable causal path along which to roll. So the table and the apple are born! My body brought them into existence in the sense that it selected them and only them from the whirlwind. Entirely ignoring all kinds of other stuff.

Parks: This whirlwind is disconcerting. As if we lived in chaos. Maybe you should find some more reassuring term. But summarizing, there is an apple relative to my body, another apple relative to your body, another apple relative to a bat’s body, or a bird’s, or a fly’s, or a possum’s, or a microbe’s, and so on. Aren’t there too many apples? Should we call them apples at all?

Manzotti: Go back to velocities. Each object has infinite velocities. But this does not bother anyone, nor does it disturb our knowledge of physics. As long as you know what reference frame you’re in, multiple velocities is not an issue. It’s the same with the apple. My apple and your apple are each relative to a different body. So we have relative apples, as we have relative velocities.

Parks: But what about weight, color, size. Are they relative too?

Manzotti: Weight is relative to gravitational pull. Colors vary with light, sensory receptors, surroundings, surfaces, and so on.

Parks: And mass?

Manzotti: Mass is not something we experience. We experience weight. More generally, we perceive an object’s resistance to being lifted, pushed, or pulled. I’m not claiming that all physical properties are relative, only that the properties we experience are relative to our bodies.

Parks: What about size, though? We perceive size, but you’re surely not claiming that an object’s size changes.

Manzotti: If you insist on a fixed frame of reference, a ruler for example, you could say the size of an object remains the same in relation to the ruler placed alongside it. The apple will always be four inches high and the ruler will always give the same reading. But if you consider the object in relation to the body, obviously it changes with distance.

Parks: Sorry, I’ve done some homework here. In 1758, David Hume wrote, “The table which we see seems to diminish as we remove farther from it. But the real table, which exists independent of us, suffers no alteration. It was, therefore, nothing but its image which was present to the mind.” Respond in fifty words, please!

Manzotti: Hume was wrong. The real table he had in mind is akin to the pre-1600 notion of absolute speed. Adapting Bertrand Russell’s famous comment on the law of causality, we could say, Hume’s “real” table along with notions of absolute velocity are “a relic of a bygone age, surviving, like the monarchy, only because they are erroneously supposed to do no harm.” The table, like any other object, is relative and, as far as we’re concerned, relative to our bodies. Since our bodies change and move, the world around us also changes, and so do we, since the thing that is our experience is the world around us.

Parks: Let’s say I accept that each of us sees a different relative apple. All the same, only one of us can eat it. Then there’s only one apple.

Manzotti: Each of us is a different relative apple. Each conscious mind is the collection of objects that exist relative to that object which is our body. Of course, if I eat the apple, it will no longer be part of your experience.

Parks: What about when people die? Their consciousness is gone, but the world remains the same. Surely this proves that experience is a personal thing inside us, not outside, in the world.

Manzotti: Not at all. Imagine you’re driving your car straight toward the leaning tower of Pisa at fifty miles per hour. Does the tower have a relative velocity with respect to you?

Parks: I would never dream of doing such a thing, but yes, of course. The tower has a relative velocity of exactly fifty miles per hour.

Manzotti: Now, your car is suddenly destroyed. A drone strike takes it out. Why not? Boom. Your car is dead, you are dead. Does the tower still have a relative velocity of fifty miles per hour?

Parks: Obviously not. Or not in relation to my particular car.

Manzotti: So, this property of the tower ceased to exist when the approaching car was eliminated. The moving car brought into existence a world of relative velocities that were neither subjective nor internal to the car. Right? It would be mad to look for the relative velocity of the tower inside the car. There is no emergent relative velocity bubbling up from its carburetors. In the same way, each body brings into existence a world of relative objects, that are, nevertheless, external physical objects. Not things that emerge from your brain, or representations that well up in there. When the body stops working and dies, that world of experience, your consciousness, which is external to your body, ceases to exist as well. But not, of course, the whirlwind it was selected from.

Parks: Essentially, you’re turning everything inside out. The experience I thought was inside is outside.

Manzotti: That’s the idea. Look at the world, and you’ll find yourself. Look inside your experience, and you find… what? The world that surrounds your body.

Parks: Well, of course, we’ve talked over this many times and over the last year or so I have made a big effort—if only out of curiosity—to stop thinking of my experience as in my head and understand it instead as the very world I move in. And I’m going to confess that to a degree this works and is even cheering. I mean, it’s heartening to think that this tree I see, this cup I touch, is not a representation, not the concoction of my neurons, but simply reality, albeit reality relative to my body and my neurons.

However, our sense that consciousness is in the head does not arise, it seems to me, from our immediate sensory experience of the world, but from all the consciousness that has nothing to do with an immediate external object. By which I mean, language use, thinking, memories, and so on. And here it gets difficult to see how your approach can work. How can you claim that a dream is not in the head? The eyes are closed. The room is in darkness, and yet maybe I’m in my kayak negotiating an exciting mountain river. This, it seems to me, is where your whole house of cards comes tumbling down.

Manzotti: Ok, dreams it is. And, why not hallucinations, too. We will tackle them. We will consider how the brain-based approach explains them—very easily actually—and then how the Mind-Object Identity Theory explains them. But before we do that, I’m afraid we’re going to have to sacrifice one other sacred cow. The now.

Parks: The now?

Manzotti: Just as there is no absolute object, so there is no absolute instant of time that is now. This is crucial.

Parks: Crucial, maybe, but definitely too much for me today. Right now, I need a break.