Is it possible to put some order into our thoughts about consciousness, memory, perception, and the like? Hardly a day goes by without some in-depth article wondering whether computers can be conscious, whether our universe is some kind of simulation, whether mind is a unique quality of human beings or spread out across the universe like butter on bread. Many of us are not even sure what we believe in this department, or whether what we believe would bear much scrutiny from philosophers or neuroscientists.

For a number of years I have been talking about these matters almost daily with Riccardo Manzotti, the philosopher, psychologist, and robotics engineer. I have now suggested to him that we condense our conversations into a series of focused dialogues to set out the standard positions on consciousness, and suggest some alternatives. For my own part I’d like to add some reflections on the social implications of the various theories for what we think about consciousness, which is as much as to say what we think about who and what we are, inevitably has consequences for how we relate to one another, and to the world. But our first problem will be one of definition.

—Tim Parks

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

Tim Parks: Riccardo, what do we mean when we say “consciousness”? Are we talking about perceptive experience, memory, thought, trains of thought, or mental life in general?

Riccardo Manzotti: For most people “consciousness” will have various meanings and include awareness, self-awareness, thinking in language. But for philosophers and neuroscientists the crucial meaning is that of feeling something, having a feeling you might say, or an experience. An easy way to think about it would be pain. Instinctively we all agree that feeling a pain is something. It’s an experience. That is why we don’t like to hurt animals, because we have good reason to suspect that they feel what happens to them. And this feeling of what happens to us characterizes our existence. The technical term is “phenomenal experience,” or again “conscious experience,” but frankly both sound a tad redundant since experience is always something we feel.

Parks: I remember David Chalmers, a philosopher we’ll no doubt be talking about at some point, defining consciousness as an internal flow of images, “a movie playing inside your head,” and probably a lot of people would agree with him. But you want to stick to something more basic.

Manzotti: A definition like that suggests that we know a lot more than we do: that there are images in our heads, that they move forward in sequence, that there is some kind of split between the image and someone (who?) observing the image. It’s all very problematic. The truth is that we do not know what consciousness is. That’s why we’re talking about it as a problem. What we do know is that the way we experience reality, I mean that we feel the things that happen to us, does not really match up with our current scientific picture of the physical world.

Parks: In what respect?

Manzotti: Well, consider this: If we didn’t know that human beings experience the world, that they feel things, would we be able to deduce it from what we know about neurophysiology? Really, no. There is nothing about the behavior of neurons to suggest that they are any different with respect to consciousness than, say, liver cells or red blood cells. They are cells doing what cells do best, namely, keeping entropy low by generating flows of ions such as sodium, potassium, chloride, and calcium and releasing neurotransmitters as a consequence. All of that is wonderful but far removed from the fact that I experience a light blue color when I watch the morning sky. That is, it’s not easy to see how the physical activity of the neurons explains my experience of the sky, let alone a process like thinking.

Parks: So we might say that consciousness is the word we use to refer to the fact that rather than just physiological activity, mute like any other physical event—the sky in the morning, a cloud crossing the sun—we have experience, we have a feeling of that event?

Manzotti: Exactly. Instead of a world where we merely interact with external occurrences—the way a flower opens in the sun, or water freezes in the cold—we also have experience of the occurrence, the sun, the icy weather, and so on. This addition of experience (or in future we may want to suggest that experience and occurrence are one!) would be puzzling enough in itself. But it is even more puzzling that experience is usually described as experience of something else, of something that is not me. I experience a red apple. You experience a piece of music. Ruth experiences a landscape. How is this possible since, if we leave aside quantum mechanics (for the moment), our traditional view of nature tells us that an object is what it is and nothing more? William James put this very clearly when he asked, How can the room I am sitting in be simultaneously out there and, as it were, inside my head, my experience? We still have no answer to that question.

Parks: So another way we could look at this would be to say that the fact of consciousness points to a flaw in our explanation of reality. Or at least amounts to a big challenge as to how we understand reality.

Manzotti: Right. Once we have defined and placed all the pieces of the physical jigsaw—chemistry, physics, evolution, general relativity, quantum mechanics, DNA, evolution, Higgs Boson, the lot—there is still something that does not add up—namely the fact that we don’t simply do things, we also experience the world around us. Consciousness. What David Chalmers famously called the hard problem.

Parks: In other words, consciousness is not something that current science would predict.

Manzotti: No. Why doesn’t our behavior simply happen, taking its course the way the planets follow their orbits? We don’t know. Just as cosmologists don’t know what dark matter is. All we know is that there is something that doesn’t add up and very likely points to some profound error in our assumptions about reality. That’s what we should be concentrating on, rather than getting into elaborate and suggestive metaphors like “movies in the head.”

Parks: You seem now to be defining consciousness by what it is not, or at least as an area of incomprehension. But can I push you toward a more positive definition? I mean, are we talking about a thing—a physical object or a process? I presume we rule out spirits and souls.

Manzotti: To speak of spirits and souls would amount to an admission of defeat, at least for a scientist or philosopher. The truth is that we just don’t know a priori the nature of physical reality. This is a point Bertrand Russell made very strongly back in the 1920s. The more we investigate the physical, the more varied and complex it appears. Imagine a huge puzzle in which everything must fit together with everything else. When there’s something that doesn’t seem to match up, we turn it this way and that to see if we can make it fit somehow, but if it won’t, we have to assume that we’ve put the other pieces together wrongly, we’ve got a false picture.

That’s how science proceeds. So we have moments of revolution—Copernicus, Galileo, Newton—when all the pieces have to be rearranged, what Thomas Kuhn famously described as paradigm shifts.

There’s no reason why we should approach the problem of consciousness any differently. We have to find how to fit it into our existing understanding of reality, or change our version of reality to have it fit in with consciousness. Until we do that, we risk having a dualistic vision of the world, like the one suggested by Descartes, on the one side the physical, on the other something rather mysterious, call it the spiritual.

Parks: But again, should we be thinking of consciousness as a thing, or a process?

Manzotti: Well, if the world that surrounds us is made of things, objects, and physical processes, consciousness is likely to be one of them. People tend to be extremely hesitant when approaching consciousness and to treat it as a special case. But I’m not sure that’s helpful. If it is a real phenomenon, and most people agree that it is, why shouldn’t it be like all other physical phenomena, something made of matter and energy whose activity is explicable by its physical properties?

Parks: So, assuming consciousness is a thing, a physical thing, or an amalgam of things, what do we do with the word “mental”?

Manzotti: Good question! Actually “mental” isn’t so different, at least as regards its function, from a word like “spiritual.” Neither word has a precise referent. I’m afraid we’re going to run into a lot of words like this in the course of these conversations. It’s as if certain terms we use had been given a special license to operate outside the constraints of the physical world. The philosopher Sidney Shoemaker observed that the notion of the “mental” amounts to a kind of ontological dustbin. Anything that doesn’t fit with our current picture of physical reality is moved to the bin whose main purpose is to collect together all the things we can’t explain. It’s a sort of quiet dualism: you don’t say the word “spirit,” but in fact you’re splitting the world in two.

Parks: A bin is hardly flattering. Surely when we talk about our mental lives we’re simply thinking of everything that makes human beings special, different—our thoughts, our language-based lucubration.

Manzotti: Absolutely. There are good reasons to be fond of a notion like “the mental,” because it places our minds above the constraints of physical necessity. It’s a comforting idea. We are above nature. We are special. We have our mental lives. Separate from the nitty-gritty of matter. Unfortunately, we have no scientific justification for this belief, which is very likely just another manifestation of what Freud described as human narcissism, the desire to believe ourselves at once at the center of the universe, yet in some way superior to and even separate from the nature around us.

How convenient, when you can’t explain something, to say, well, that means we’re special, we’re not like the rest of the natural world. But science works on the assumption that nature is one and that all phenomena must fit in the same system and obey the same laws; hence the fact that we experience the world—i.e., consciousness—must be a natural phenomenon which, like all other natural phenomena, is physical, I mean made of matter and energy.

Parks: This brings us, I think, to the dominant view of what consciousness is today: internalism. Can you explain?

Manzotti: Internalism is the notion that whatever consciousness is, it must happen inside the head. It’s fairly obvious why we might think this. We tend to feel that we are located where our senses are; hence people suppose that consciousness is somewhere behind our eyes and between our ears. This not to mention the many social reasons for identifying with our bodies in general and our faces in particular, which are crucial to social interaction. And since of course we can’t see consciousness in another person, but only manifestations of it—smiles, grimaces—we assume it is hidden inside the head, that is, in the brain. Since, again, the brain is by far the most complex of our organs, with something like 85 billion neurons, all with hundreds if not thousands of connections to other neurons, it seems a reasonable candidate when you’re looking for something you don’t understand. Or it did seem so when we knew less about it.

Parks: I know you have strong objections to internalism and can feel you straining at the leash to express them. But let’s first establish exactly what the theory is and what it claims. For example, does internalism claim that consciousness is a physical object located in space?

Manzotti: There are many strands to internalism, but on the whole, and certainly initially, yes. The idea was formalized in the 1950s by people like David Armstrong and J.J.C. Smart. They advanced the idea that consciousness is neural processes, or certain neural processes. Once they’d formed this perfectly respectable hypothesis an army of scientists set about verifying it empirically. And in fact, over the past fifty years we’ve made extraordinary progress in the development of sophisticated instruments to probe and explore the brain with all its fantastically intricate electrical and chemical activity.

Parks: And?

Manzotti: Well, neuroscientists have certainly found a huge number of correlates of consciousness; that is, for all kinds of sensory experiences they have established which parts of the brain are active, and the nature of that activity. This is of enormous interest and scientifically very sound.

Parks: I hear a but coming.

Manzotti: Well, a correlate of consciousness is not consciousness. When scientists look for AIDS or DNA, they look for the thing itself, not a mere correlate. This is a problem: how to get from the neural correlate—the fact that there’s neural activity when I experience something—to the thing itself, the experience? As Bertrand Russell almost facetiously put it, when one licks chocolate ice-cream nothing in the brain tastes like chocolate. Of course an experience also has correlates outside the brain: the sensory organs—eyes, ears, nose, skin, tastebuds—not to mention the object itself that we experience, light, soundwaves, that chocolate ice-cream, whatever. Why privilege the correlates in the brain in our attempt to locate consciousness? Why…

Parks: Stop there! Enough for today. We’ve defined consciousness as the feeling that accompanies our being in the world. We’ve looked very crudely at the conundrum its existence poses for our understanding of the world. We’ve announced the dominant scientific view of where consciousness is located: in our brains. Next time, I’d like to consider some of the claims of internalism, their implications for our current scientific account of reality, and the way internalists have reacted to their difficulties verifying their theory. Because they certainly haven’t given up. Far from it. So be prepared!