Dialogues on Consciousness E-Book

Riccardo Manzotti

• Herausgeber: ERIS
• Kategorie: Geisteswissenschaft
• Sprache: Englisch
• Veröffentlichungsjahr: 2020

Seitenzahl: 213

Beschreibung

Over a period of many years, the celebrated English novelist Tim Parks and the Italian philosopher Riccardo Manzotti have been discussing the nature of consciousness. Not long ago, Parks suggested to his friend that they condense their exchanges "into a series of focused dialogues to set out the standard positions on consciousness, and suggest some alternatives." Fifteen of the resultant conversations were edited by Parks and published in The New York Review of Books online—one of its most popular features ever.Now collected into one slim but thought-provoking volume, the dialogues reveal the profound scholarship of the two men. Their talks touch upon Aristotle and William James, the Higgs boson and Descartes, and include topics such as "Where Are Words?", "The Body and Us", "The Reality of Dreams", "The Object of Consciousness", and finally "Consciousness: What Is It?". For those of us searching for insight into some of life's most basic puzzles—how do we think? how do we perceive one another, and ourselves?—Dialogues on Consciousness will take its place alongside other classics of philosophy."This deeply and seriously ambitious book aims to do nothing less than erase the distance between perception and existence. It opens up a thrilling new vista upon the real."—David Shields"If only more philosophy books were as original, interesting and readable as this one. A beautifully clear and thought-provoking exposition in the form of a Platonic dialogue."—Iain McGilchrist"Plenty of food-for-thought without the existential angst and ennui."—Counterpunch

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Riccardo Manzotti and Tim Parks

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Contents

one The Challenge of Consciousness

two The Colour of Consciousness

three Does Information Smell?

four The Ice Cream Problem

five Am I the Apple?

six The Mind in the Whirlwind

seven Dreaming Outside our Heads

eight The Body and Us

nine Consciousness: Who’s at the Wheel?

ten A Test for Consciousness

eleven The Hardening of Consciousness

twelve Consciousness: An Object Lesson

thirteen The Pizza Thought Experiment

fourteen Consciousness: Where Are Words?

fifteen Consciousness and the World

About the Authors

ONE

The Challenge of Consciousness

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 the 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.

—T. P.

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 characterises 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.

TP 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.

RM 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, the way we feel the things that happen to us, does not really match up with our current scientific picture of the physical world.

TP In what respect?

RM 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 behaviour 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 colour 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.

TP 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?

RM 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.

TP 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.

RM 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.

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

RM No. Why doesn’t our behaviour 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’.

TP 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.

RM 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.

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

RM 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 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?

TP So, assuming consciousness is a thing, a phys­ical thing—or an amalgam of things—what do we do with the word ‘mental’?

RM 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 licence 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.

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

RM 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 centre 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, made of matter and energy.

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

RM 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.

TP I know you have strong objections to internal-ism 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?

RM There are many strands to internalism, but on the whole, and certainly initially, yes. The idea was formalised in the 1950s by people like D. M. 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.

TP And?

RM 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.

TP I hear a ‘but’ coming.

RM 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 Thomas Nagel 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, taste buds—not to mention the object itself that we ex­perience: light, sound waves, that chocolate ice cream, whatever. Why privilege the correlates in the brain in our attempt to locate consciousness? Why...

TP 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.

TWO

The Colour of Consciousness

There are no colours out there in the world, Galileo tells us. They only exist in our heads. In the first of our dia­logues about the mind, Riccardo Manzotti and I estab­lished that by ‘consciousness’ we mean the feeling that accompanies our being alive, the fact that we experience the world rather than simply interacting with it mechani­cally. We also touched on the problem that traditional sci­ence cannot explain this fact and does not include it in its account of reality. That said, there is a dominant under­standing of where consciousness happens: in the brain. This ‘internalist’, or inside-the-head, approach shares Galileo’s view that colour, smell, and sound do not exist in the outside world but only in the brain. “If you could perceive reality as it really is,” says leading neuroscientist David Eagleman, “you would be shocked by its colourless, odourless, tasteless silence”. What Riccardo and I want to do today is ask how, in the neuroscientists’ opinion, we see colour. What are the implications of believing that this ex­perience is all inside our heads? And how have scientists reacted to the difficulties they have encountered verifying this theory?

—T. P.

TIM PARKS Riccardo, when the internalists talk about conscious experience, they often use the word ‘qualia’, meaning an elementary sensation, a feeling of something, and one of their favourite examples of this is our seeing colour, our experience of colour. So how does it come about that we see colour?

RICCARDO MANZOTTI Before answering let’s pay some attention to the language we’re using, since it may determine the way we think about the whole thing. Most people say they see a colour or a coloured ob­ject, a yellow banana, say. So we have subject and object; a person sees a yellow banana. Scientists and philosophers speak of our having an experience, feel­ing, or qualia. So now we have three things, a sub­ject, an object (the banana maybe), and a feeling, in our heads. I fear both manners of speaking are po­tentially misleading.

TP I suppose it’s inevitable that standard views of experience will be built into language use, but can’t we leave this issue for another time?

RM I’m not sure we can. The fact is that the subject/ object divide, not to mention the addition of a feel­ing or ‘percept’, is particularly pertinent when we talk about colour.

TP How so?

RM Well, as you said, science tells us there’s no colour in the world. It occurs only in our brains. But, as we discussed in our first conversation, when scientists look inside the brain to see what’s going on, they find only billions of neurons exchanging electrical im­pulses and releasing chemical substances. They find what they call correlates of consciousness, not con­sciousness itself; or in this case, they find correlates of colour, but not colour itself. There is no yellow banana in the head, just the grey stuff.

TP I get it. We have no colour outside in the world and yet we can’t find the colour in our heads either. So where on earth is it? The funny thing is that for most people there is no problem at all. They see a red traffic light and they know to stop. They trust other people to stop. Most of us feel entirely confident about seeing colour and even mixing colours. To us colour seems to be an external reality, not a subjective delusion.

RM Absolutely! The unsuspecting layman will assure you that objects simply have colours as at­tributes—isn’t our banana, for example, very yellow exactly the same way it’s six inches long? Well, un­fortunately not, because it could easily be shown that bananas are only yellow under a certain light. Change the light and the banana might look green. But it will always be six inches long.

TP I had thought colour was revealed, as it were, by a refraction, or breaking up of light.

RM That is the other traditional claim, still widely taught in school, that colours exist in light, or that dif­ferent colours are different wavelengths of light. And of course the colours of the rainbow immediately come to mind. But that explanation doesn’t work 100 percent either. The same wavelength, for example, will give rise to different colours if the surrounding environ­ment is different. To his credit, Newton himself, who actually introduced the word ‘spectrum’ into the En­glish language to refer to the range of possible colours, eventually dismissed the idea that colours are literally contained in the light. “For the Rays, to speak proper­ly, are not coloured. In them there is nothing else than a certain Power and Disposition to stir up a Sensation of this or that Colour”. Three hundred years on, what and where colours actually are remains a mystery.

TP Yet so many books on neuroscience purport to tell us how we perceive colour.

RM Indeed. From the nineteenth century on, scien­tists have been looking for colours inside the nervous system. First, they worked on the hypothesis that colours were qualities that the retina or the optic nerve in­troduced into the signals that they then sent to areas further along in the brain. However, nothing satisfac­tory was ever found, nor is it clear what they imagined they might find. In the twentieth century neurophys­iologists went deeper and deeper into the brain, trac­ing the activity of neurons they believed related to the experience of colour, until, around 1973, a provisional consensus was reached when the neuroscientist Semir Zeki presented evidence that part of the visual cortex in the occipital lobe at the back of the head, an area called V4, was responsible for colour perception, this because damage to that area led to a loss of colour perception and colour memory. But once again, fur­ther research suggested that matters were more com­plicated, that other areas and neurons could come into play. In short, there is still a great deal of debate on the subject.

TP I appreciate that you’ve spent a great deal of time researching the history of science’s dealings with colour, but are you telling me that contemporary neu­roscience offers no dominant view on the matter?

RM Well, the current textbook view goes like this.

The world is a place where objects reflect light, sunlight being the dominant source and as it were, the default setting as far as the kind of light is con­cerned. However, each object reflects only a subset of that light. Rays from this subset enter our retina and stimulate a honeycomb of cells, known as cones, because of their conical shape, whose function is to react differently to different portions of the visible spectrum (we remember, of course, that only a small part of the vast electromagnetic spectrum is visible). Most humans—animals are rather different—possess three kinds of cones, referred to as S, M, and L cones, depending on whether they react more vigorously to short, medium, or long-range light wavelengths. The ‘output’ of these cells is first merged together in the retina, then sent via the optical nerve to various cor­tical areas—including the famous V4. And that’s as much as we know.

TP Riccardo, you just gave me the whole explana­tion without ever using the word colour.

RM I know! Oddly, this is a theory of colour that does not need the notion of colours. I suppose the reason is that however carefully you follow neural signals from the retina along the optic nerve and across the brain, you don’t actually come across anything like a colour, or anything that explains colour perception. You could almost say that the notion of colour is useless to colour science, unless...

TP Unless?

RM Unless we bring consciousness back in the pic­ture. Colours are something we experience, individually and collectively. But without our experience of colour, science would have no reason to suspect its existence. There would just be fifty shades—or more likely fifty thousand shades—of electromagnetic waves. That is why even a Nobel Prize-winning biologist like Gerald Edelman tells us that reality is actually colourless; be­cause he takes reality to be what science tells us it is, not what he experiences as an individual.

TP But the implications of this ‘official’ view are profound. First, it suggests our perceptions are rad­ically separate from the external world, fenced off in­side the skull. Second, and as a result, that we all live in error and need the authority of science to tell us what reality is really like. So it gives scientists consid­erable power.

RM It’s obvious that for modern science to happen, the object had to be separated from the subject; only an elite of savants could be acquainted with the thing itself. Remember that Galileo, the founder of modern science, was also a Platonist, and Plato was a promi­nent member of his city’s elite, and the first philoso­pher to place the object of intellectual enquiry out­side of the reach of the everyday man: that is, man is trapped in the cave watching shadows on the wall while reality is outside, beyond his grasp.

TP I think the thing that most disturbed me when I read Galileo was his exhortation, which Francis Bacon agreed with, that we should do violence to our senses, deliberately go against what they tell us.

RM Absolutely. Far la ragione tanta violenza al sen­so. If science tells you the world has no colour, then you must fight against your perception that in fact it is leaping with colour.

TP So, while in our first dialogue, you suggest­ed that consciousness is a challenge for our present scientific model of reality, in that nothing in science predicts the existence of consciousness, now it seems you are going a step further and suggesting that con­sciousness is a kind of battleground between science and the lay community—with science telling us that conscious experience, colour for example, is a brain-based illusion, while for the layman it is reality itself.