Natasha Mitchell: All in the Mind, here on ABC Radio National, great to have your ears. Natasha Mitchell on board.

Today, a possibly unsettling or perhaps comforting encounter with your inner life.

Thomas Metzinger: Nobody has ever seen a will. How many grams does a will weigh? What colour does it have? We don't find a will in the brain, that's for sure. What we have is the conscious experience of having free will, of actually deliberating, wanting something, of weighing different goals against each other and so on, and that conscious experience of free will, that will be explained by science.

And the question is...many people in the general public feel an uneasiness with this debate about freedom of the will. Imagine there was no freedom of the will, that if we had a theory that said that, we couldn't really believe that theory, it would make us sick. I mean, how could you imagine that every thought, every intention you are consciously experiencing right now has been predetermined by something unconscious outside of your reality. The people that have that experience are usually in psychiatric institutions. Our brains were never made for this.

Natasha Mitchell: Our brain was never made for this, which is the very reason of course we want to talk about such things on All in the Mind.

So, what makes you you?

I hope you've heard of our Gene Pool project over at the ABC social media site, Pool, that's the very question we're posing there at the moment and we'd love your contributions, stories, poems, pictures, sounds, whatever takes your fancy. Pool.org.au is the place, and we'll be broadcasting some of your Gene Pool offerings in a few weeks.

Of course the other thing that makes you feel like a you is that ineffable sense of self that we each possess, of being a 'me' within. It's an experience that's preoccupied philosophers for centuries, including my guest today, but scientists on the whole stayed away, seeing it as a flaky, subjective sort of a problem, impossible to empirically unravel.

Top philosopher of mind Thomas Metzinger has been central in the global push to change that, part of a renaissance which includes the formation of the Association for the Scientific Study of Consciousness, which he is about to take up the presidency of.

Professor Metzinger is based at the Johannes-Gutenberg University in Mainz in Germany, and has long collaborated with neuroscientists and artificial intelligence researchers and others. And in his new book The Ego Tunnel: The Science of the Mind and the Myth of the Self he makes the case that there is no such thing as a self. He's my guest on the show today.

Natasha Mitchell: Welcome to Australia, Thomas, and to ABC Radio National, great to have you on the show.

Thomas Metzinger: I am very happy to be here.

Natasha Mitchell: Look, if I was to ask you who you are, the self that goes by the name of Thomas Metzinger from Germany, I wonder how you'd answer, because you make the provocative argument that there is no such thing as a self, that there never has been, that there never will be.

Thomas Metzinger: Yes, it's actually not so provocative, it's not an original idea at all. Many philosophers, David Hume, in the Anglo Saxon universe have said that for a long time. Who am I? The physical body certainly exists, the organism exists, but organisms are not selves. I don't deny that there is a self-y feeling. I certainly feel like someone, but there is no such thing. There is neither a non-physical thing in a realm beyond the brain or the physical world that we could call a self, but there's also no thing in the brain that we must necessary call a self.

Of course Buddhist philosophy had that point 2,500 years ago. So the idea that, as philosophers say, the self is not a substance, that it is something that can stay and hold itself in existence, even if the body or the brain were to perish, that's not a very breathtaking and new idea. What I am interested in is to understand why we just cannot believe that this is so. We have the feeling there is an essence in us, a deepest, inner core. We have this feeling that there must be something that is just not right about neuro-scientific theories about self consciousness, there's something beyond it. And I want to understand what that deepest core is because that's the origin of the subjectivity of consciousness.

Natasha Mitchell: But in a sense to say that one doesn't have a soul, it's not uncontroversial amongst, I guess, non-believers in religion, say, but it's perhaps more complicated to say that we don't have a self because then, as you've suggested in your book, this really unhinges us at our core, doesn't it, because who then is the feeler of your feelings and the dreamer of your dreams, as you put it, the experiencer of your conscious experience and, perhaps more controversially, who is the driver of our free will?

Thomas Metzinger: That's right, a first approximation could be to say what we have called the self in the past is not a thing in the brain and not a thing in some metaphysical realm beyond the brain, but it's a process...

Natasha Mitchell: So it's not a little man or woman inside our heads...

Thomas Metzinger: ...that looks at pictures. But the experience of looking, of being directed to one's own feelings or to one's sensory perceptions of the outside world, this is itself an image. There is nobody looking at the image, it's like the camera is part of the picture or the viewing is itself a part of the process of viewing. This is how a first-person perspective emerges in our own case, the question is, okay, if it's not a thing, if it's not something in the brain, what kind of a process is it? And I think it's a process, as philosophers say, of representing, that is of making an image, and that process is not there all the time. You know you have a conscious self in dreams, you have one in your waking life. During anaesthesia or during dreamless sleep there is no such thing as this process of self-ing, if I may call it like that.

Natasha Mitchell: Cute. Yes, that's a nice way of putting it. You see the ego as a sort of virtual reality game, in fact, that the feeling we have of a self is rather like virtual reality and that we're stuck in a sort of never ending flight simulation.

Thomas Metzinger: Right, the thing has to simulate the pilot too, to be really good, to create a user surface, like a Windows desktop, onto its own mechanics which are just too complicated to understand, so we need a simplified version of what is actually going on in ourselves. And that simplified version is conscious experience. The conscious self...that's what we call consciousness today. I think it's also something like a computational tool that helps us to navigate the world, like the mouse pointer that tells you 'You are here and now and you can control this and that'. And so we actually have something like a simulation of the world, and I think the amazing thing is Mother Nature has done this much better than any computer today. Millions of years ago we have this feeling of being present in the world as selves, and that's a great achievement of natural evolution and the evolution of nervous systems, but it's virtual.

Natasha Mitchell: So interesting. So, consciousness literally is the appearance of an inward world, but that world is a very partial representation of the material, the real world that we experience, is your suggestion.

Thomas Metzinger: Right, it's just like your physics teacher perhaps told you in high school, in front of your eyes there is just a raging ocean of different wavelength mixtures, there are no coloured objects. Coloured objects are the models your brain creates of visual objects. The world model our brains create has many dimensions, it has the dimension of auditory perceptions, of sound and speech and music, of colours and smell. But it also has these gut feelings, all our body perceptions, moods, emotions, all these are parts of...it's like a thin film which creates the boundary to the world. I'm not saying there is no outside world and I'm also not saying we're not in contact with it and we don't act in the world, but just for conscious experience, how it appears to you, that is actually an inner space, that is something that is very local in your own brain. In the real world there is no self as one substantial thing. That's part of the simulation.

Natasha Mitchell: It's slightly unsettling, though, this sense that we're not really actually experiencing the world that we are in touch with. Your interest in consciousness is both as an academic and a philosopher but it also stems from a series of very early intense personal experiences you had as a young man. Tell me about a series of out-of-body experiences you had.

Thomas Metzinger: Many people today like to talk about first-person methods in consciousness research and never practice them themselves. On the one hand I believe that we could have much better science and a much better science of consciousness if many of the involved researchers would do things like meditating or other practices in, say, altered states of consciousness, but as a philosopher I don't believe that in a strict sense that we can just look into our own minds and find facts there. I usually keep this completely separate, this is my private life, but I am also first a long-term meditator and just by chance in my early 20s I've had six or seven spontaneous out-of-body experiences. Nothing dramatic, just when falling asleep. They made me think a lot because I was just writing my PhD thesis on the mind/body problem and I just found out that everybody on the research frontier is a materialist...

Natasha Mitchell: So they locate the mind in the body and very much in the brain.

Thomas Metzinger: Or to the point that they say that there has never been anything like a mind, that's the most ruthless form of eliminative materialism, as we call it.

Natasha Mitchell: It's just, the mind is the brain.

Thomas Metzinger: We have been describing the states in our own head wrong for millennia. There are no mental states, that's one variant, or any substantial entity behind the physical brain, and then suddenly in my own life I realise, oh, I have actually been out of my physical body, I'd better not tell anybody about it.

Natasha Mitchell: What was that experience like? Because in fact out-of-body experiences are incredibly common across the population. I mean, we're not talking about the kind of kooky interpretations of alien abductions and the like, but out-of-body experiences are a natural part of many people's conscious experience.

Thomas Metzinger: Eight to fifteen per cent of the population have it one time in their life, after accidents, when waking up from anaesthesia, or a typical natural situation, if you leave things like meditation or drugs aside, is so-called sleep paralysis, and that is how it started for me. It wasn't pleasant at all, I thought it was horrific. Have you ever had the experience; wow, I can't move my body anymore, it's sleeping already, and I am still wide awake...

Natasha Mitchell: What happened? You were lying in your bed...so you're suspended above your body looking back at it?

Thomas Metzinger: No, for most people this only happens when they try to sit up or so, jump up, and then they suddenly really jump up and they float out and then they realise this physical body is behind them. That would be a very simple and natural out-of-body experience that hundreds of thousands of people have had on the planet. Then you suddenly have the experience that your self, your centre of thinking, of attending, is located out of your physical body for the first time and often you experience a second kind of bodily shape, an ethereal light body in which you can fly around. That is of course, or so I have claimed, the root of our belief in souls because human beings have had these experiences at all times and in all cultures, long before there was science or philosophy, and people have made theories about what could that be because it's pretty realistic, at least as realistic as your lucid dreams are. It's at least as realistic as waking life, and then you have a problem. I mean, are you going to tell people about this or are they going to send you to the psychiatrist...

Natasha Mitchell: Exactly, you've spent many years trying to explain it, but scientifically. And in fact you describe yourself in your new book as an intrepid philosophical psychonaut. It sounds like you've tried all sorts of experiments on yourself, as well as in collaboration with scientists and their subjects. You got your surgeon to alter your anaesthetic regime when you went under surgery once.

Thomas Metzinger: Yes, they were really cynical. They said, 'So young man, you've been writing your thesis about the mind/body problem. Observe yourself now!' And they knocked me out and it was very nasty, it was a very death-oriented waking up phase, there was nothing that resembled an out-of-body experience, it was in parts frightening. No special discovery there. But if you want to enhance your lucid dreaming, one thing you could do, a simple old classic, is stop drinking at noon, then stare at a glass of water just before you go to sleep in a really thirsty condition, then you place half a tablespoon of salt in your cheek and go to sleep and make a firm commitment as soon as you are there again and you realise you cannot lift it to drink, you will become aware that you're dreaming now. I can guarantee what's going to happen.

Natasha Mitchell: You've done it?

Thomas Metzinger: I've done it, it's terrible.

Natasha Mitchell: Lucid dreaming is an interesting one for you. I want to come back to the out-of-body experience work too, but lucid dreaming, I guess, is the ultimate internal virtual reality. So this is when you dream but you can actually cognitively control the sequence of your dreams, can't you. Why do they interest you so much as a philosopher interested in the nature of consciousness and that feeling of a self that we have?

Thomas Metzinger: One thing I have written about, for instance, is what happens in the transition from an ordinary dream to that lucid dream. Full lucidity means that you become aware of your own agency, that you can control the dream world and your own body, you can go through walls or make experiments, and there are very interesting experiments. For instance, you could ask, as a philosopher, another dream figure if they actually think they have a conscious mind of their own or if they actually think they're a subsystem of your dreaming brain right now. That's an interesting discussion to have.

Natasha Mitchell: Spooky.

Thomas Metzinger: But more seriously what I'm of course interested in is the functional building blocks of what I call the human self model. So in the transition from the ordinary to the lucid dream, for instance, you gain all these memories you have lost, who you are in waking life, that you have had lucid dreams perhaps before, and most importantly perhaps you can control the focus of your attention, focus your own mind. I don't know if you've ever realised this but in ordinary dreams you cannot really control your attention.

And then it's of course an amazing, a unique state of consciousness from a theoretical point of view because it's the only state of consciousness where you are not a naïve realist, where you actually experience everything as an internal simulation and you lose this feeling of moving in a real external world. Then you know you are moving in a simulation and you can try all kinds of things.

Natasha Mitchell: You tried buying a really expensive device at one stage that was marketed as the ultimate lucid dreaming tool. There's a lot of hype around lucid...I mean, it can be caught up in the new age movement, can't it.

Thomas Metzinger: Right, because it's so impressive if you've had one or two, but then I find that all these popular books basically lie to people. It's not so easy, and all these books and tools and machines try to tell you it would be easy to become a frequent and stable lucid dreamer. It isn't.

Natasha Mitchell: Let's come back to out-of-body experiences because here is a very interesting problem for you. You've collaborated with the German neuroscientist Olaf Blanke and I've had him on the show before, and you designed a series of incredible experiments where you have people experience the feeling, the illusion of an out-of-body experience using a virtual reality projection. So you get them to feel like their self is inside a virtual body projected in front of them. It's quite extraordinary. Why did you want to do this?

Thomas Metzinger: What we have created actually is what we have termed now technically a full body illusion. What doesn't happen is that you see yourself, so to speak, out of the eyes of this avatar as you would in a full blown out-of-body experience, it's not exactly the same thing.

Natasha Mitchell: Why does that interest you philosophically?

Thomas Metzinger: Because one of many elements of the conscious self I need to understand is the sense of ownership. Long before language and concepts you have the feeling 'this is me', and we also have this, for instance, in using tools. It may be very important when you use a rake or a stick for the period while you use it to actually incorporate it into your body image. What I was interested in was is there something like a global sense of ownership. Not just a feeling of owning your hand or maybe owning a thought, but owning the body as a whole, and can that be experimentally manipulated, that was the question.

Natasha Mitchell: And in some sense that feeling of owning a body as a whole is essential to the feeling we have of being a self, a self contained within our own unique body.

Thomas Metzinger: Absolutely. My theory—big, unintelligible philosophical theory—says that we identify with this image of our body because we cannot recognise it as an image. And if my theory is correct, there should be just this one element of global identification and it should be easy to control it experimentally. That was the idea behind it. But I must also...one warning, the idea of global ownership for our body as whole is a dangerous idea because it introduces a second self, like a little man that does the owning.

Natasha Mitchell: Exactly. You just can't get away from this problem, philosophers!

Thomas Metzinger: Yes, it's awful, isn't it, but what I think is actually happening is the conscious self is a fantastic tool that emerged in natural evolution that allows a body to own itself. That's what is actually happening, for instance, when you wake up in the morning and a conscious self emerges, that is when the body that was sleeping boots up this virtual reality tool to own itself, to control itself in a new way. That is where selfhood came from.

Natasha Mitchell: Speaking about evolution, what do you think was most adaptive about...most beneficial to us as a species about this unique sense of selfhood that it seems that we possess?

Thomas Metzinger: Well, in general of course it's good for an animal to have a model of its own body. How fast can I run? Should I pick a fight with this guy? Or better not? How far can I jump to the next branch? How heavy am I? What are my collision properties? That was important. So I think bodily self models have been on this planet for a long time.

The next invention was emotions, to know what is in your own interest and in the interest of your offspring, to have the experience of being...I guess, bonding, you say in English, to other conscious selves.

Natasha Mitchell: Your own research looks at the many ways the feeling of being a self inside a body is compromised in some way, so the out-of-body experience work. There's phantom limb syndrome, and this is the experience where people might lose a part of themselves through amputation, a limb, but they still feel like it's there. Why does that phantom limb feeling interest you?

Thomas Metzinger: That's of course the number one obvious example of what I mean by a bodily self model. The model is still there in the brain after the amputation, although it loses input. Say your left arm is gone, and then in a normal case what you have is that this phantom limb becomes shorter, recedes into the stump and then it disappears. What happens is that the map of your body in the brain has to reorganise itself after you lost that limb. There are neighbouring areas who see, 'ha, there's a piece of garden nobody uses anymore, I could use these computational resources', and they invade that region. And on the level of conscious experience you experience this as pain in the phantom limb and the phantom limb becoming shorter, and then it disappears. Then your map is reorganised.

Then there are of course more interesting and complicated questions, like almost 25% of children born without limbs, arms or legs, when they begin to talk, suddenly the parents ask, 'What are you doing there?' And they say, 'Well, we're learning how to calculate in school, I'm doing four plus three with my ghost fingers.' And they say, 'What? You've had ghost fingers all the time?'

Natasha Mitchell: Wow. You wonder whether that's intrinsic to them, it's something innate that we're all born with, a sense of a body, or whether or not that's a sort of learnt thing.

Thomas Metzinger: Exactly, but there is of course a question; is there an innate component to the sense of selfhood? Or, say, if you had no social environment, no mother, would you perhaps never develop a sense of self? Of course these are unethical experiments we cannot do but there are all these questions behind.

Natasha Mitchell: Intriguing. In your work you're also very concerned about our changing conception of consciousness with the help of neuroscience, and this is something you're very enthusiastic about, given your partnerships with scientists for many years, but you're calling for a new field of ethics, Thomas, a ethics of consciousness. What would be the focus of such an ethics and why do you see it as being so crucial?

Thomas Metzinger: We do have this brand new discipline since 2002 of neuro-ethics where one investigates the ethical consequences of new technologies that come out of neuroscience, like new lie detectors, cognitive enhancers, brain implants and so on. Our image of ourselves, the image of man, of humankind, is changing faster and more dramatically then through any other scientific revolution in the past. In a way we are destroying a lot of what mankind has believed in during the last 4,000 years, but it's also clear that in this emerging vacuum neuroscience will not be able to put something new into this vacuum.

Natasha Mitchell: You see it as that we're witnessing a disenchantment of the self, which is interesting because you've just banished the self in this conversation.

Thomas Metzinger: Well, who is ready to do that, who could even understand, honestly, what that would mean. I think we're seeing a lot of good things, interesting things. For instance, we'll be able to heal psychiatric diseases much better in a few decades, but we'll also pay a price. We'll pay an emotional price, there are these unsettling things about freedom of the will, then there is the social cultural price we're going to pay for it which is much harder to assess.

I mean, how will our culture actually react to a naturalistic turn in our image of man, if there's no supernatural root even in our minds anymore, and we actually have to come to terms with the fact that not only our bodies but also our minds are results of a process that had no goal, that was driven by chance events...I mean, how are we going to come to terms with this? Will we develop a culture of denial, or will we all become vulgar materialists? And I think something that could help us to take this step in integrating all this brand new knowledge and the new potentials for changing our brains and our minds technologically...

Natasha Mitchell: And pharmaceutically.

Thomas Metzinger: And pharmaceutically, that's what we're researching in my cognitive enhancers group...how are we going to make this historical transition in an optimal way? And I think, to put it very simply, we could do it by just thinking not only about what is a good action but what is a good state of consciousness. What states of consciousness do we want to show our children? How can neuroscience help us with optimising education? What states of consciousness are we allowed to impose, to force upon animals? Are all these experiments in, say, primate research, in consciousness research, in neuroscience ethically tenable? What states of consciousness should be illegal in our society? New drugs. What states of consciousness do we want to foster and cultivate?

It's also a question of preserving our dignity in the face of these sometimes very sobering discussions, and in developing a cultural response to it. Can modern science help me? It's not only about defending ourselves, it's also about what I call riding the tiger; can all this new knowledge help us to improve our autonomy, maybe also our rationality? How can I take responsibility and charge for the way I deal with my own brain? Can it help us to die better deaths? Who knows? But I think we should all, not only philosophers and scientists but all of us, start to think about what we want to do with all these new brain/mind technologies. Just looking the other way won't make it go away.

Natasha Mitchell: Thomas Metzinger, thank you very much for joining me on the program, it's been a really compellingly interesting conversation.

Thomas Metzinger: Thank you very much.

Natasha Mitchell: And philosopher Professor Thomas Metzinger's new book is called The Ego Tunnel: The Science of the Mind and the Myth of the Self, published by Basic Books. He was in Australia this past week for the conference of the Australasian Society for Cognitive Science at Macquarie University.

And if you want hear more on the extraordinary experience of anarchic hand syndrome, for example, or on the ethical consequences of the modern remaking of our brain, I've popped some extra audio excerpts on the All in the Mind blog.

Thanks to co-producer Anita Barraud and studio engineer Carey Dell. I'm Natasha Mitchell, off in search of that ever elusive self. Elusive and illusive it seems!