Consciousness Explained

"Yes, he is going to tell you what the answer is to a point. But he’s not going to say ‘this is what consciousness is.’ He says ‘this is what you thought consciousness was, and you were wrong.’ The main point he’s making throughout is that you have to give up your intuitions. He uses wonderful examples that I love to make his points. I should say, though, that some readers don’t love them. If anyone is reading this and they try that book and hate it, then give up. It seems that people go in two directions: they either love the way he writes, or they hate it. I love it, with all his mad examples and neologisms. He’s dismantling a whole lot of illusions and saying that when you dismantle them the ‘hard problem’ has disappeared. We still can’t solve all the mysteries about it; there’s still a lot more to understand; but the problem is not what you thought it was. At least, that’s my interpretation of what he meant by Consciousness Explained . And you’ve tied yourself into a problem there, as did David Chalmers who invented the term ‘hard problem’, by saying ‘giving rise.’ As soon as you say ‘you’ve got this matter’ and ‘you’ve got this stuff called consciousness’, and you’ve got consciousness arising from it , then you’ve committed yourself to a kind of dualism. It may not be substance dualism or ontological dualism, but it’s some kind of dualism that you’ve committed yourself to because you’ve still got two things – matter and consciousness. Many people – myself and Dan Dennett included – would say that this is an ill-posed problem. We can’t actually pose the problem better yet, though we can ask better questions. Where I really agree with Dan Dennett is that this is the job that we need to do first. We need to expose all the illusions and delusions that we have about our own minds before we can even begin to know what the right questions are to ask about experience. What we’re talking about is this: this subjective experience…We’re doing this interview by Skype, and it’s your experience of staring at me on a computer screen, and my experience of staring at you on a screen. That’s what we’re trying to account for. Dennett is not saying that that experience doesn’t exist. He’s saying it’s not what you thought it was. He begins the book with him sitting in a rocking chair and experiencing the light on the leaves and so on. That’s what he’s talking about. People accuse him of explaining consciousness away, but he’s actually talking about immediate experience and trying to understand it. He’s saying here are all the illusions, let’s get them out of the way first. The main one is the non-existence of what he labels the ‘Cartesian theatre.’ I think his book is an extended riff on rejecting this illusion. The point he makes is this: nearly everyone rejects Cartesian dualism because, for obvious reasons, it doesn’t work. But when they do so, they fail to throw out the idea of the audience who sits in the brain watching a screen, as it were, in the theatre. He calls this the ‘Cartesian theatre’ because it’s a sort of vestige of Cartesian dualistic thinking that remains even if you’ve thrown out the ontological dualism itself. I think he’s right about that. He calls people who think this way ‘Cartesian materialists.’ I write ‘CM’ in every book I’m reading again and again when people say things like ‘and then this entered consciousness’ or ‘this perception became conscious’ or ‘this became part of the contents of consciousness.’ All these are dead giveaways that you are still thinking in terms something like this: there are some processes going on in the brain that are conscious, and there are some that are not consciousness. Therefore, what we have to do is understand the difference between the conscious processes and the unconsciousness processes. That is where the whole hunt for the ‘neural correlates of consciousness’ comes from. But if you take Dennett’s ideas seriously, as I do, then all this is complete nonsense. “We’re so deluded about what consciousness is that we need to throw out this distinction and start again” In fact, where he ends up – and I end up somewhere similar – is saying that we’re so deluded about what consciousness is that we need to throw out this distinction and start again. In fact, I would argue, consciousness is an attribution we make. We attribute consciousness to certain perceptions that we have and certain actions that we do – usually after the fact or while we’re doing it – and therefore we believe in a continuous stream of consciousness, and we believe in a continuous self, and all of these things which aren’t true. This is how we become deluded. We imagine this stream of consciousness on the screen and we imagine ourselves having those experiences. In reality, there are just brain processes going on. He develops his multiple drafts theory out of this to say that there are lots and lots of versions of any perceptions going through the brain. The critical point is that it’s not that some are really conscious, and the rest unconscious . That is only an attribution that we put on a perception if we get enough access to it, can speak about it, can act upon it and so on. That’s why he calls it ‘fame in the brain.’ When something spreads enough in the brain, then it can cause you to press a button or talk to someone and say ‘I’m conscious of looking at you now.’ There is nothing more to consciousness than that. That’s what he meant by ‘consciousness explained.’ That book came out in 1991 and has been widely read yet, 26 years on, I would say the majority of researchers in consciousness studies are still what he would call Cartesian materialists."

"This follows very nicely from the last point that we were discussing because Dennett, in this book, is trying to dismiss the dualist intuition completely, to get rid of it entirely. When he says ‘ Consciousness Explained’ , in my understanding it’s explicable for Dennett because he thinks we are mistaken in thinking that there is anything beyond what is within the realm of normal physical descriptions of mechanisms and their dispositions and their properties. That’s all we need. This book has been a massive influence on me, as has Dennett himself, throughout my career. And I’ve been lucky enough to get to know him a bit over the last few years as part of my role in the Canadian Institute for Advanced Research, where I’m a co-director, and he’s one of our main advisors. It’s been a real pleasure. Having first read his book when I was just starting my undergraduate degree at Cambridge, I never thought that a quarter of a century later I’d be discussing consciousness with him in person. In fact, this year, he very kindly set a proof of my book for his philosophy class at Tufts University. They read through the whole thing and grilled me about it for six hours, which was a great. An exhilarating torture, it was. But I’m not sure I’m entirely convinced by his perspective, which is itself a good thing because it maintains an ongoing conversation. When I first read Consciousness Explained, my reaction was ‘No, this doesn’t really explain consciousness because it doesn’t explain the redness of red, it doesn’t explain why a physical system has conscious experiences.’ To me, what Dennett is getting at is why we might be mistaken about the questions we’re asking. He comes up with all these beautiful thought experiments that deconstruct one of the central assumptions people often make when thinking about consciousness: the idea of a ‘Cartesian theater’. This, to me, is where he’s really strong. This assumption is one among a number that people frequently make when thinking about consciousness. Another is that consciousness exists. I have this assumption, too. I think consciousness is a real thing—there’s a ‘there’ there. Another common assumption is that there’s some inner observer, some inner self, that is in some sense the experiencer of conscious experiences, the audience for an inner movie that is played out somewhere in the brain. This is the Cartesian theatre. We can say that we’re not dualist and that we think materialism is a good way forward, but we can still fall into this Cartesian theatre fallacy and speak, even if only implicitly, in these terms. As Dennett often says now, the hard question is, ‘and then what happens?’ There’s always this temptation to say ‘Okay, and then what happens? At what point does whatever-is-going-on transmogrify into qualia?’ Dennett’s book does an outstanding job of deconstructing these ideas, of making us realize there is no need—in fact, it doesn’t make any sense—to think of a place, a Cartesian theatre, where everything comes together for the benefit of an inner observer. His ‘multiple drafts’ theory of consciousness is a positive proposal for what happens when you don’t make that assumption. There are just processes unfolding all over the place in time and in space, retrospectively woven together in something the brain later interprets as a stable ‘center of narrative gravity’, as he calls it. Even though it’s a popular book, it’s also philosophically detailed. I confess I have not read all the way through it again since my first encounter, though I have repeatedly dipped in over the years. I include it here because I am convinced it remains very relevant. And, evidently, it has guided consciousness research, not only mine, but that of many colleagues too, over the years. People sometimes have a love-hate relationship with the book, they either think he’s completely right, or they think he’s completely wrong because he’s missing – or dismissing—the qualitative, phenomenal aspects that are at the heart of the matter. I don’t have that love-hate relationship. I like some bits of it very much indeed. But I’m not convinced by the whole. A more recent way of putting Dennett’s core thesis would be that it’s a fantastic set of ideas about what the philosopher Ned Block has called ‘access consciousness’—those parts of our conscious experience that are manifest through broad availability to other cognitive functions and processes. Dennett has called this kind of consciousness ‘fame in the brain’. When we’re aware of something in this sense, we can behave very flexibly with respect to it. Dennett’s book does a wonderful job of highlighting how these aspects of consciousness can be explained by mechanisms—a story that has since been elaborated in modern neurobiological theories of consciousness, such as the global workspace theory, developed primarily by Bernard Baars and Stanislas Dehaene. And maybe that’s all there is to the problem. I mean, some people would say once you’re done explaining access consciousness, that’s it, job done. But some others, like Ned Block , would say, ‘No, there’s also phenomenal consciousness, there’s an aspect of consciousness which doesn’t have to involve cognitive access.’ An example would be the ‘redness’ of seeing red. Sure, we can—and usually do—have cognitive access to our experiences of red. But the redness itself is not defined in terms of this access. Dennett’s theory doesn’t directly go after phenomenal consciousness, it tries to indirectly undermine the need to propose its existence. It’s often thought of as an ‘illusionist’ view on consciousness, where we’re somehow mistaken that redness as a qualitative property exists. As I said, I’m not convinced by that. That’s part of his huge legacy. Let’s make that abundantly clear. One of the joys of my career over the last 25 years has been to witness, and to some extent participate in, this cross-fertilization between philosophy and neuroscience. Dennett is not the only philosopher in my list here. Later, Thomas Metzinger comes up. Then there’s Andy Clark—a close colleague at Sussex, and there are now many brilliant philosophers of mind who are incredibly literate with neuroscience. Some of them, like my colleague Jakob Hohwy, not only know the relevant science but also run experiments themselves. To have this conjunction of philosophically informed neuroscientists on the one hand, and neuroscientifically informed philosophers on the other, is both exciting and necessary. You’re just not going to make progress without having this mixture of expertise."

"Well, Dennett is more wary of identifying mental states with brain states. It’s not that he thinks there’s anything nonphysical about the mind – far from it, he’s a committed physicalist. But he doubts that our everyday talk of mental states will map neatly onto scientific talk about brain states – that for every mental state a person has there will be a discrete brain state that causes all the associated behaviour. He sees folk psychology as picking out patterns in people’s behaviour, rather than internal states. (So his view is closer to that of Ryle, with whom he studied in the early 1960s.) That’s a large theme in his work. But in this book he’s addressing a different issue. In the years after Armstrong wrote, the idea that mental states are brain states became widely accepted, though it was tweaked in various ways. But some people argued that the view couldn’t explain all the features of mental states – in particular, consciousness. These people agreed with Armstrong that the mind is a physical thing, but they argued that it’s a physical thing with some non-physical properties – properties that can’t be explained in physical terms. This view is known as property dualism (as opposed to substance, or Cartesian, dualism, which holds that the mind is a non-physical thing ). There’s a standard story about what consciousness is. When you’re having an experience – let’s say, seeing a blue sky – there’s brain activity going on. Nerve impulses from your retinas travel to your brain and produce a certain brain state, which in turn produces certain effects (it produces the belief that the sky is blue, disposes you to say that the sky is blue, and so on). This is the familiar story from Armstrong. And in principle a neuroscientist could identify that brain state and tell you all about it. But – the story goes – there’s something else going on too. It is like something for you to see the blue sky – the experience has a subjective quality, a phenomenal feel, a quale (from the Latin word ‘qualis’, meaning of what kind ; the plural is ‘qualia’). And this subjective quality is something that the neuroscientists couldn’t detect. Only you know what it’s like for you to see blue (maybe blue things look different to other people). The same goes for all other sense experiences. There’s an inner world of qualia – of colours and smells and tastes, pains and pleasures and tickles – which we experience like a show in a private inner theatre. Now if you think about consciousness this way, then it seems incredibly mysterious. How could the brain – a spongy, pinky-grey mass of nerve cells – create this inner qualia show that’s undetectable by scientific methods? This is what David Chalmers has called the hard problem of consciousness. Not an answer to the hard problem exactly. It’s more that he thinks it’s a pseudo-problem. He thinks that that whole picture of consciousness is wrong – there’s no inner theatre and no qualia to be displayed there. Dennett thinks that that picture is a relic of Cartesian dualism, and he calls the supposed inner theatre the Cartesian Theatre . We used to think there really was an inner observer – the immaterial soul. Descartes thought that signals from the sense organs were channelled to the pineal gland in the centre of the brain, from where they were somehow transmitted to the soul. Nowadays few philosophers believe in the soul, but Dennett thinks they still hang on to the idea that there’s a sort of arena in the brain where sensory information is assembled and presented for consciousness. He calls this view Cartesian materialism , and he thinks it’s deeply misconceived. Once we give up Cartesian dualism and accept that mental processes are just hugely complex patterns of neural activity, then we must give up the picture of consciousness that went with it. You’ve got to break down this idea of the inner show standing between us and the world. There’s no need for the brain to recreate an image of external world for the benefit of some internal observer. It’s a kind of illusion. I think Dennett would say that’s exactly what it should sound like – after all, if materialism is true, then we are machines, biological machines, made from physical materials. If you’re going to explain consciousness, then you need to show how it is made out of things that aren’t conscious. The 17th century philosopher Gottfried Leibniz said that if you could blow up the brain to the size of a building and walk around it, you wouldn’t see anything there that corresponded to thinking and experience. That can be seen as a problem for materialism, but in fact it’s just what materialism claims. The materialist says that consciousness isn’t something extra, over and above the various brain systems; it’s just the cumulative effect of those systems working as they do. And Dennett thinks that one of the effects of those brain systems is to create in us the sense that we have this inner world. It seems to us when we reflect on our experiences that there is an inner show, but that is an illusion. Dennett’s aim in the book is to break down that illusion, and he uses a variety of thought experiments to do so. Yes, that’s right – though Dennett’s thought experiments often draw on scientific findings. Here’s one he uses in the book. You see a woman jog past. She is not wearing glasses, but she reminds you of someone who does, and that memory immediately contaminates your memory of the running woman so that you become convinced she was wearing glasses. Now Dennett asks how this memory contamination affected your conscious experience. Did the contamination happen post-consciousness, so that you had a conscious experience of the woman without glasses, and then the memory of this experience was wiped and replaced with a false memory of her with glasses? Or did it happen pre-consciousness, so that your brain constructed a false conscious experience of her as having glasses? If there were a Cartesian Theatre, then there should be a fact of the matter: which scene was displayed in the theatre – with glasses or without them? But Dennett argues that, given the short timescale in which all of this happened, there won’t be a fact of the matter. Neuroscience couldn’t tell us. “Some critics say that Dennett should have called his book ‘Consciousness Explained Away’” Suppose we were monitoring your brain as the women passed and found that your brain detected the presence of a women without glasses before it activated the memory of the other woman with glasses. That still wouldn’t prove that you had a conscious experience of a woman without glasses, since the detection might have been made non-consciously. Nor would asking you have settled it. Suppose that as the women passed we had asked you whether she was wearing glasses. If we had put the question at one moment you might had said she wasn’t, but if we’d asked it a fraction of a second later you might have said she was. Which report would have caught the content of your consciousness? We can’t tell – and neither could you either. All we – or you – can really be sure of is what you sincerely think you saw, and that depends on the precise timing of the question. The book is packed with thought experiments like this, all designed to undermine the intuitive but misleading picture of the Cartesian Theatre. The first thing to stress is that he’s not trying to provide a theory of consciousness in qualia-show sense, since he thinks that consciousness in that sense is an illusion. Some critics say that Dennett should have called his book ‘Consciousness Explained Away’, and up to a point they are right. He is trying to explain away consciousness in that sense . He thinks that that conception of consciousness is confused and unhelpful, and his aim is to persuade us to adopt a different one. In this respect Dennett’s book is a kind of philosophical therapy. He’s trying to help us give up a bad way of thinking, into which we easily lapse. Support Five Books Five Books interviews are expensive to produce. If you're enjoying this interview, please support us by donating a small amount . As for what we put in place of the Cartesian Theatre, there are two main parts to Dennett’s story. The first is what he calls the ‘Multiple Drafts’ model of consciousness. This is the idea that there isn’t one canonical version of experience. The brain is continually constructing multiple interpretations of sensory stimuli (woman without glasses, women with glasses), like multiple drafts of an essay, which circulate and compete for control of speech and other behaviour. Which version we report will depend on exactly when we are questioned – on which version has most influence at that moment. In a later book Dennett speaks of consciousness as fame in the brain . The idea is that those interpretations that are conscious are those that get a lot of influence over other brain processes – that become neurally famous. This may seem a rather vague account, but again I think Dennett would say that that’s how it should seem, since consciousness itself is vague. It isn’t a matter of an inner light being on or off, or of a show playing or not playing. The second part of Dennett’s story is his account of conscious thought – the stream of consciousness that James Joyce depicted in his novel Ulysses . Dennett argues that this isn’t really a brain system at all; it’s a product of a certain activity we humans engage in. We actively stimulate our own cognitive systems, mainly by talking to ourselves in inner speech. This creates what Dennett calls the Joycean Machine – a sort of program running on the biological brain, which has all kinds of useful effects. Dennett thinks there are both conceptual and empirical reasons for preferring the Multiple Drafts view. He thinks the idea of a qualia show contains all sorts of confusions and inconsistences – that’s what the thought experiments are designed to tease out. But he also cites a lot of scientific evidence in support of the Multiple Drafts view – for example, concerning how the brain represents time. And he certainly thinks his offers a better explanation of our behaviour, including our intuitions about consciousness. Positing a private undetectable qualia show doesn’t explain anything. Of course, Dennett’s views are controversial, and there are many important philosophers who take a very different view – most notably David Chalmers in his 1996 The Conscious Mind . But for my money Dennett’s line on this is the right one, and I think time will bear that out."