9:59:59.000,9:59:59.000 Just over a year ago, 9:59:59.000,9:59:59.000 for the third time in my life, 9:59:59.000,9:59:59.000 I seized to exist. 9:59:59.000,9:59:59.000 I was having a small operation, 9:59:59.000,9:59:59.000 and my brain was filling with anesthetic. 9:59:59.000,9:59:59.000 I remember a sense of detachment[br]and falling apart 9:59:59.000,9:59:59.000 and a coldness. 9:59:59.000,9:59:59.000 And then I was back, 9:59:59.000,9:59:59.000 drowsy and disoriented, 9:59:59.000,9:59:59.000 but definitely there. 9:59:59.000,9:59:59.000 When you wake from a deep sleep, 9:59:59.000,9:59:59.000 you might feel confused about the time[br]or anxious about oversleeping, 9:59:59.000,9:59:59.000 but there's always a basic sense[br]of time having passed, 9:59:59.000,9:59:59.000 of a continuity between then and now. 9:59:59.000,9:59:59.000 Coming out from[br]anesthesia is very different. 9:59:59.000,9:59:59.000 I could have been under for five minute, 9:59:59.000,9:59:59.000 five hours, 9:59:59.000,9:59:59.000 five years, 9:59:59.000,9:59:59.000 or even 50 years. 9:59:59.000,9:59:59.000 I simply wasn't there. 9:59:59.000,9:59:59.000 It was total obliviion. 9:59:59.000,9:59:59.000 Anesthesia -- 9:59:59.000,9:59:59.000 it's a modern kind of magic. 9:59:59.000,9:59:59.000 It turns people into objects -- 9:59:59.000,9:59:59.000 and then we hope -- 9:59:59.000,9:59:59.000 back again into people. 9:59:59.000,9:59:59.000 And in this process 9:59:59.000,9:59:59.000 is one of the greatest remaining[br]mysteries in science and philosophy. 9:59:59.000,9:59:59.000 How does consciousness happen? 9:59:59.000,9:59:59.000 Somehow, within each or our brains, 9:59:59.000,9:59:59.000 the combined activity[br]of many billions of neurons, 9:59:59.000,9:59:59.000 each one a tiny biological machine, 9:59:59.000,9:59:59.000 is generating a conscious experience. 9:59:59.000,9:59:59.000 And not just any conscious experience -- 9:59:59.000,9:59:59.000 your conscious experience[br]right here and right now. 9:59:59.000,9:59:59.000 How does this happen? 9:59:59.000,9:59:59.000 Answering this question is so important 9:59:59.000,9:59:59.000 because consciousness[br]for each of us is all there is. 9:59:59.000,9:59:59.000 Without it, there's no world, 9:59:59.000,9:59:59.000 there's no self, 9:59:59.000,9:59:59.000 there's nothing at all. 9:59:59.000,9:59:59.000 And when we suffer, 9:59:59.000,9:59:59.000 we suffer conciously, 9:59:59.000,9:59:59.000 whether it's through mental[br]illness or pain. 9:59:59.000,9:59:59.000 And if we can experience[br]joy and suffering, 9:59:59.000,9:59:59.000 what about other animals? 9:59:59.000,9:59:59.000 Might they be conscious, too? 9:59:59.000,9:59:59.000 Do they also have a sense of self? 9:59:59.000,9:59:59.000 And as computers get faster and smarter, 9:59:59.000,9:59:59.000 maybe there will come a point, 9:59:59.000,9:59:59.000 maybe not too far away, 9:59:59.000,9:59:59.000 when my iPhone develops a sense[br]of its own existence. 9:59:59.000,9:59:59.000 I actually think the prospects[br]for a conscious AI are pretty remote. 9:59:59.000,9:59:59.000 And I think this because[br]my research is telling me 9:59:59.000,9:59:59.000 that consciousness has less to do[br]with pure intelligence 9:59:59.000,9:59:59.000 and more to do with our nature[br]as living and breathing organisms. 9:59:59.000,9:59:59.000 Consciousness and intelligence[br]are very different things. 9:59:59.000,9:59:59.000 You don't have to be smart to suffer, 9:59:59.000,9:59:59.000 but you probably do have to be alive. 9:59:59.000,9:59:59.000 In the story I'm going to tell you, 9:59:59.000,9:59:59.000 our conscious experiences[br]of the world around us, 9:59:59.000,9:59:59.000 and of ourselves within it, 9:59:59.000,9:59:59.000 are kinds of controlled hallucinations 9:59:59.000,9:59:59.000 that happen with, through[br]and because of our living bodies. 9:59:59.000,9:59:59.000 Now, you might have heard[br]that we know nothing 9:59:59.000,9:59:59.000 about how the brain and body[br]give rise to consciousness. 9:59:59.000,9:59:59.000 Some people even say it's beyond[br]the reach of science all together. 9:59:59.000,9:59:59.000 But in fact, 9:59:59.000,9:59:59.000 the last 25 years have seen an explosion[br]of scientific work in this area. 9:59:59.000,9:59:59.000 If you come to my lab [br]at the University of Sussex, 9:59:59.000,9:59:59.000 you'll find scientists[br]from all different disciplines, 9:59:59.000,9:59:59.000 and sometimes even philosophers. 9:59:59.000,9:59:59.000 All of us together trying to understand[br]how conscioussness happens 9:59:59.000,9:59:59.000 and what happens when it goes wrong. 9:59:59.000,9:59:59.000 The strategy is very simple. 9:59:59.000,9:59:59.000 I'd like you to think about consciousness 9:59:59.000,9:59:59.000 in the way that we've[br]come to think about life. 9:59:59.000,9:59:59.000 At one time, 9:59:59.000,9:59:59.000 people thought the property[br]of being alive could not be explained 9:59:59.000,9:59:59.000 by physics and chemisty. 9:59:59.000,9:59:59.000 That life had to be more[br]than just mechanism. 9:59:59.000,9:59:59.000 But people no longer think that. 9:59:59.000,9:59:59.000 As biologists got on with the job 9:59:59.000,9:59:59.000 of explaining the properties[br]of living systems 9:59:59.000,9:59:59.000 in terms of physics and chemistry -- 9:59:59.000,9:59:59.000 things like metabolism, reproduction,[br]homeostasis -- 9:59:59.000,9:59:59.000 the basic mystery of what life is[br]started to fade away, 9:59:59.000,9:59:59.000 and people didn't propose any more[br]magical solutions, 9:59:59.000,9:59:59.000 like a force of life or an élan vital. 9:59:59.000,9:59:59.000 So as with life, 9:59:59.000,9:59:59.000 so with consciousness. 9:59:59.000,9:59:59.000 Once we start explaining its properties 9:59:59.000,9:59:59.000 in terms of things happening[br]inside brains and bodies, 9:59:59.000,9:59:59.000 the apparently insoluble mystery[br]of what consciousness is 9:59:59.000,9:59:59.000 should start to fade away. 9:59:59.000,9:59:59.000 At least that's the plan. 9:59:59.000,9:59:59.000 So let's get started. 9:59:59.000,9:59:59.000 What are the properties of consciousness? 9:59:59.000,9:59:59.000 What should a science[br]of consciousness try to explain? 9:59:59.000,9:59:59.000 Well, for today I'd just like to think[br]of consciousness in two different ways. 9:59:59.000,9:59:59.000 There are experiences[br]of the world around us, 9:59:59.000,9:59:59.000 full of sights, sounds and smells, 9:59:59.000,9:59:59.000 there's multisensory, panoramic,[br]3D, fully immersive inner movie. 9:59:59.000,9:59:59.000 And then there's conscious self. 9:59:59.000,9:59:59.000 The specific experience[br]of being you or being me. 9:59:59.000,9:59:59.000 The lead character in this inner movie, 9:59:59.000,9:59:59.000 and probably the aspect of consciousness[br]we all cling to most tightly. 9:59:59.000,9:59:59.000 Let's start with experiences[br]of the world around us 9:59:59.000,9:59:59.000 with the important idea of the brain[br]as a prediction engine. 9:59:59.000,9:59:59.000 Imagine being a brain. 9:59:59.000,9:59:59.000 You're locked inside a bony skull, 9:59:59.000,9:59:59.000 trying to figure out what's[br]out there in the world. 9:59:59.000,9:59:59.000 There's no lights inside the skull. 9:59:59.000,9:59:59.000 There's no sound either. 9:59:59.000,9:59:59.000 All you've got to go on is streams[br]of electrical impulses 9:59:59.000,9:59:59.000 which are only indirectly related[br]to things in the world, 9:59:59.000,9:59:59.000 whatever they may be. 9:59:59.000,9:59:59.000 So perception -- 9:59:59.000,9:59:59.000 figuring out what's there -- 9:59:59.000,9:59:59.000 has to be a process of informed guess work 9:59:59.000,9:59:59.000 in which the brain combines[br]these sensory signals, 9:59:59.000,9:59:59.000 with its prior expectations or beliefs[br]about the way the world is 9:59:59.000,9:59:59.000 to form its best guess of what[br]caused those signals. 9:59:59.000,9:59:59.000 The brain doesn't hear sound or see light. 9:59:59.000,9:59:59.000 What we perceive is its best guess[br]of what's out there in the world. 9:59:59.000,9:59:59.000 Let me give you a couple[br]of examples of all this. 9:59:59.000,9:59:59.000 You might have seen this illusion before, 9:59:59.000,9:59:59.000 but I'd like you to think[br]about it in a new way. 9:59:59.000,9:59:59.000 If you look at those two patches, A and B, 9:59:59.000,9:59:59.000 they should look to you to be[br]very different shades of gray, right? 9:59:59.000,9:59:59.000 But they are in fact[br]exactly the same shade. 9:59:59.000,9:59:59.000 And I can illustrate this. 9:59:59.000,9:59:59.000 If I put up a second version[br]of the image here, 9:59:59.000,9:59:59.000 and join the two patches[br]with a gray-colored bar, 9:59:59.000,9:59:59.000 and you can see there's no difference. 9:59:59.000,9:59:59.000 It's exactly the same shade of gray. 9:59:59.000,9:59:59.000 And if you still don't believe me, 9:59:59.000,9:59:59.000 I'll bring the bar across[br]and joing them up. 9:59:59.000,9:59:59.000 It's a single colored block of gray, 9:59:59.000,9:59:59.000 there's no difference at all. 9:59:59.000,9:59:59.000 So this isn't any kind of magic trick. 9:59:59.000,9:59:59.000 It's the same shade of gray, 9:59:59.000,9:59:59.000 but take it away again, 9:59:59.000,9:59:59.000 and it looks different. 9:59:59.000,9:59:59.000 So what's happening here 9:59:59.000,9:59:59.000 is that the brain is using[br]its prior expectations 9:59:59.000,9:59:59.000 built deeply into the circuits[br]of the visual cortex 9:59:59.000,9:59:59.000 that a cast shadow dims[br]the appearance of a surface, 9:59:59.000,9:59:59.000 so that we see B as lighter[br]than it really is. 9:59:59.000,9:59:59.000 Here's one more example, 9:59:59.000,9:59:59.000 which shows just how quickly[br]the brain can use new predictions 9:59:59.000,9:59:59.000 to change what we consciously experience. 9:59:59.000,9:59:59.000 Have a listen to this. 9:59:59.000,9:59:59.000 ([Sound]) 9:59:59.000,9:59:59.000 Sounded strange, right? 9:59:59.000,9:59:59.000 Have a listen again and see[br]if you can get anything. 9:59:59.000,9:59:59.000 ([Sound]) 9:59:59.000,9:59:59.000 Still strange. 9:59:59.000,9:59:59.000 Now listen to this. 9:59:59.000,9:59:59.000 Recording: I think breakfast[br]is a really terrible idea. 9:59:59.000,9:59:59.000 (Laughter) 9:59:59.000,9:59:59.000 Which I do. 9:59:59.000,9:59:59.000 So you heard some words there, right? 9:59:59.000,9:59:59.000 Now listen to the first sound again. 9:59:59.000,9:59:59.000 I'm just going to replay it. 9:59:59.000,9:59:59.000 ([Recording]) 9:59:59.000,9:59:59.000 Yeah? 9:59:59.000,9:59:59.000 (Laughter) 9:59:59.000,9:59:59.000 So you can now hear words there. 9:59:59.000,9:59:59.000 One more more for luck. 9:59:59.000,9:59:59.000 ([Recording]) 9:59:59.000,9:59:59.000 OK, so what's going on here? 9:59:59.000,9:59:59.000 The remarkable thing is the sensory[br]information coming into the brain 9:59:59.000,9:59:59.000 hasn't changed at all. 9:59:59.000,9:59:59.000 All that's changed is your[br]brain's best guess 9:59:59.000,9:59:59.000 of the causes of that sensory information. 9:59:59.000,9:59:59.000 And that changes what you[br]consciously hear. 9:59:59.000,9:59:59.000 All this puts the brain[br]basis of perception 9:59:59.000,9:59:59.000 in a bit of a different light. 9:59:59.000,9:59:59.000 Instead of perception depending largely[br]on signals coming into the brain 9:59:59.000,9:59:59.000 from the outside world, 9:59:59.000,9:59:59.000 it depends as much, 9:59:59.000,9:59:59.000 if not more, 9:59:59.000,9:59:59.000 on perceptual predictions flowing[br]in the opposite direction. 9:59:59.000,9:59:59.000 We don't just passively[br]perceive the world, 9:59:59.000,9:59:59.000 we actively generate it. 9:59:59.000,9:59:59.000 The world we experience comes[br]as much if not more 9:59:59.000,9:59:59.000 from the inside out 9:59:59.000,9:59:59.000 as from the outside in. 9:59:59.000,9:59:59.000 Let me give you one more[br]example of perception 9:59:59.000,9:59:59.000 as this active, constructive process. 9:59:59.000,9:59:59.000 Here we've combined immersive[br]virtual reality with image processing 9:59:59.000,9:59:59.000 to simulate the effects of overly[br]strong perceptual predictions 9:59:59.000,9:59:59.000 on our experience. 9:59:59.000,9:59:59.000 In this panoramic video, 9:59:59.000,9:59:59.000 we've tranformed the world -- 9:59:59.000,9:59:59.000 which is in this case Sussex Campus -- 9:59:59.000,9:59:59.000 into a psychedilic playground. 9:59:59.000,9:59:59.000 We've processed the footage using[br]an alogrithm based on Google's Deep Dream 9:59:59.000,9:59:59.000 to simulate the effects of overly strong[br]perceptual predictions. 9:59:59.000,9:59:59.000 In this case, to see dogs. 9:59:59.000,9:59:59.000 And you can see this[br]is a very strange thing. 9:59:59.000,9:59:59.000 When perceptual[br]predictions are too strong, 9:59:59.000,9:59:59.000 as they are here, 9:59:59.000,9:59:59.000 the result looks very much like the kinds[br]of hallucinations people might report 9:59:59.000,9:59:59.000 in altered states, 9:59:59.000,9:59:59.000 or perhaps even psychosis. 9:59:59.000,9:59:59.000 Think about this for am minute. 9:59:59.000,9:59:59.000 If hallucination is a kind[br]of uncontrolled perception, 9:59:59.000,9:59:59.000 then perception right here and right now[br]is also a kind of hallucination, 9:59:59.000,9:59:59.000 but a controlled hallucination 9:59:59.000,9:59:59.000 in which the brain's predictions[br]are being reigned in 9:59:59.000,9:59:59.000 by sensory information from the world. 9:59:59.000,9:59:59.000 In fact, we're all[br]hallucinating all the time, 9:59:59.000,9:59:59.000 including right now, 9:59:59.000,9:59:59.000 it's just that when we agree[br]about our hallucinations, 9:59:59.000,9:59:59.000 we call that reality. 9:59:59.000,9:59:59.000 (Laughter) 9:59:59.000,9:59:59.000 Now I'm going to tell you that your[br]experience of being a self, 9:59:59.000,9:59:59.000 the specific experience of being you, 9:59:59.000,9:59:59.000 is also a controlled hallucination[br]generated by the brain. 9:59:59.000,9:59:59.000 This seems a very strange idea, right? 9:59:59.000,9:59:59.000 Yes, visual illusions[br]might deceive my eyes, 9:59:59.000,9:59:59.000 but how could I be deceived[br]about what it means to be me? 9:59:59.000,9:59:59.000 For most of us, 9:59:59.000,9:59:59.000 the experience of being a person[br]is so familiar, so unified 9:59:59.000,9:59:59.000 and so continuous 9:59:59.000,9:59:59.000 that it's difficult not[br]to take it for granted. 9:59:59.000,9:59:59.000 But we shouldn't take it for granted. 9:59:59.000,9:59:59.000 There are in fact many different way[br]we experience being a self. 9:59:59.000,9:59:59.000 There's the experience of having a body 9:59:59.000,9:59:59.000 and of being a body. 9:59:59.000,9:59:59.000 There are experiences[br]of perceiving the world 9:59:59.000,9:59:59.000 from a first person point of view. 9:59:59.000,9:59:59.000 There are experiences[br]of intending to do things 9:59:59.000,9:59:59.000 and of being the cause of things[br]that happen in the world. 9:59:59.000,9:59:59.000 And there are experiences of being[br]a continuous and distinctive person 9:59:59.000,9:59:59.000 over time, 9:59:59.000,9:59:59.000 built from a rich set of memories[br]and social interactions. 9:59:59.000,9:59:59.000 Many experiments show, 9:59:59.000,9:59:59.000 and psychiatrists and[br]neurologists know very well 9:59:59.000,9:59:59.000 that these different ways in which[br]we experience being a self 9:59:59.000,9:59:59.000 can all come apart. 9:59:59.000,9:59:59.000 What this means is the basic[br]background experience 9:59:59.000,9:59:59.000 of being a unified self is a rather[br]fragile construction of the brain, 9:59:59.000,9:59:59.000 another experience, 9:59:59.000,9:59:59.000 which just like all others, 9:59:59.000,9:59:59.000 requires explanation. 9:59:59.000,9:59:59.000 So let's return to the bodily self. 9:59:59.000,9:59:59.000 How does the brain generate[br]the experience of being a body 9:59:59.000,9:59:59.000 and having a body? 9:59:59.000,9:59:59.000 Well, just the same principles apply. 9:59:59.000,9:59:59.000 The brain makes its best guess 9:59:59.000,9:59:59.000 about what is and what is not[br]part of its body. 9:59:59.000,9:59:59.000 There's a beautiful experiment[br]in neuroscience to illustrate this. 9:59:59.000,9:59:59.000 And unlike most neuroscience experiments, 9:59:59.000,9:59:59.000 this is one you can do at home. 9:59:59.000,9:59:59.000 All you need is one of these. 9:59:59.000,9:59:59.000 (Laughter) 9:59:59.000,9:59:59.000 And a couple of paint brushes. 9:59:59.000,9:59:59.000 In the rubber hand illusion, 9:59:59.000,9:59:59.000 a person's real hand is hidden from view. 9:59:59.000,9:59:59.000 And that fake rubber hand[br]is placed in front of them. 9:59:59.000,9:59:59.000 Then both hands are simultaneously[br]stroked with a paintbrush 9:59:59.000,9:59:59.000 while the person stares at the fake hand. 9:59:59.000,9:59:59.000 Now for most people, 9:59:59.000,9:59:59.000 after a while, 9:59:59.000,9:59:59.000 this leads to the very uncanny sensation 9:59:59.000,9:59:59.000 that the fake hand is[br]in fact part of their body. 9:59:59.000,9:59:59.000 And the idea is that the congruence[br]between seeing touch and feeling touch 9:59:59.000,9:59:59.000 on an object that looks like hand, 9:59:59.000,9:59:59.000 and is roughly where a hand should be, 9:59:59.000,9:59:59.000 is enough evidence for the brain[br]to make its best guess 9:59:59.000,9:59:59.000 that the fake hand is in fact[br]part of the body. 9:59:59.000,9:59:59.000 (Laughter) 9:59:59.000,9:59:59.000 So you can measure[br]all kinds of clever things. 9:59:59.000,9:59:59.000 Like you can measure skin conductants 9:59:59.000,9:59:59.000 and start and responses, 9:59:59.000,9:59:59.000 but there's no need. 9:59:59.000,9:59:59.000 It's clear the guy in blue[br]has assimilated the fake hand. 9:59:59.000,9:59:59.000 This means that even experiences[br]of what our body is 9:59:59.000,9:59:59.000 is kind of best guessing -- 9:59:59.000,9:59:59.000 a kind of controlled[br]hallucination by the brain. 9:59:59.000,9:59:59.000 There's one more thing. 9:59:59.000,9:59:59.000 We don't just experience our bodies[br]as objects in the world from the outside, 9:59:59.000,9:59:59.000 we also experience them from within. 9:59:59.000,9:59:59.000 We all experience the sense[br]of being a body from the inside. 9:59:59.000,9:59:59.000 And sensory signals coming from[br]the inside of the body 9:59:59.000,9:59:59.000 are continually telling the brain[br]about the state of the internal organs, 9:59:59.000,9:59:59.000 how the heart is doing, 9:59:59.000,9:59:59.000 what the blood pressure is like, 9:59:59.000,9:59:59.000 lots of things. 9:59:59.000,9:59:59.000 And this kind of perception, 9:59:59.000,9:59:59.000 which we call intereception, 9:59:59.000,9:59:59.000 is rather over-looked. 9:59:59.000,9:59:59.000 But it's critically important 9:59:59.000,9:59:59.000 because perception and regulation[br]of the internal state of the body -- 9:59:59.000,9:59:59.000 well, that's what keeps us alive. 9:59:59.000,9:59:59.000 Here's another version of the[br]rubber hand illusion. 9:59:59.000,9:59:59.000 This is from our lab at Sussex. 9:59:59.000,9:59:59.000 And here, people see a virtual[br]reality version of their hand, 9:59:59.000,9:59:59.000 which flashes red and back 9:59:59.000,9:59:59.000 either in time or out of time[br]with their heartbeat. 9:59:59.000,9:59:59.000 And when it's flashing in time[br]with their heartbeat, 9:59:59.000,9:59:59.000 people have a strong sense that it's[br]in fact part of their body. 9:59:59.000,9:59:59.000 So experiences of having a body[br]are deeply grounded 9:59:59.000,9:59:59.000 in perceiving our bodies from within. 9:59:59.000,9:59:59.000 There's one last thing I want[br]to draw your attention to, 9:59:59.000,9:59:59.000 which is that experiences of the body[br]from the inside are very different 9:59:59.000,9:59:59.000 from experiences of the world around us. 9:59:59.000,9:59:59.000 When I look around me, 9:59:59.000,9:59:59.000 the world seems full of objects -- 9:59:59.000,9:59:59.000 tables, chairs , rubber hands, 9:59:59.000,9:59:59.000 people, 9:59:59.000,9:59:59.000 [you lot] -- 9:59:59.000,9:59:59.000 even my own body in the world, 9:59:59.000,9:59:59.000 I can perceive it as an object[br]from the outside, 9:59:59.000,9:59:59.000 but my experiences of my body from within, 9:59:59.000,9:59:59.000 they're not like that at all. 9:59:59.000,9:59:59.000 I don't perceive my kidneys here, 9:59:59.000,9:59:59.000 my liver here, 9:59:59.000,9:59:59.000 my spleen ... 9:59:59.000,9:59:59.000 I don't know where my spleen is, 9:59:59.000,9:59:59.000 but somewhere. 9:59:59.000,9:59:59.000 I don't perceive my insides as objects. 9:59:59.000,9:59:59.000 In fact I don't experience them much[br]at all unless they go wrong. 9:59:59.000,9:59:59.000 And this is important I think. 9:59:59.000,9:59:59.000 Perception of the internal[br]state of the body 9:59:59.000,9:59:59.000 isn't about figuring out what's there, 9:59:59.000,9:59:59.000 it's about control and regulation -- 9:59:59.000,9:59:59.000 keeping the physiological variables[br]within the tight bounds 9:59:59.000,9:59:59.000 that are compatible with survival. 9:59:59.000,9:59:59.000 When the brain uses predictions[br]to figure out what's there, 9:59:59.000,9:59:59.000 we can see objects[br]as the causes of sensations. 9:59:59.000,9:59:59.000 When the brain uses predictions[br]to control and regulate things, 9:59:59.000,9:59:59.000 we experience how well[br]or how badly that control is going. 9:59:59.000,9:59:59.000 So out most basic experiences[br]of being a self, 9:59:59.000,9:59:59.000 of being a body organism, 9:59:59.000,9:59:59.000 are deeply grounded in the biological[br]mechanisms that keep us alive. 9:59:59.000,9:59:59.000 And when we follow this idea[br]all the way through, 9:59:59.000,9:59:59.000 we can start to see that all[br]of our conscious experiences, 9:59:59.000,9:59:59.000 since they all depend on the same[br]mechanisms of predictive perception, 9:59:59.000,9:59:59.000 all stem from this basic[br]drive to stay alive. 9:59:59.000,9:59:59.000 We experience the world and ourselves 9:59:59.000,9:59:59.000 with, through and because of[br]our living bodies. 9:59:59.000,9:59:59.000 Let me bring things together step by step. 9:59:59.000,9:59:59.000 What we consciously see depends[br]on the brain's best guess 9:59:59.000,9:59:59.000 of what's out there. 9:59:59.000,9:59:59.000 Our experienced world[br]comes from the inside out, 9:59:59.000,9:59:59.000 not just the outside in. 9:59:59.000,9:59:59.000 The rubber hand illusion shows[br]that this applies to our experienes 9:59:59.000,9:59:59.000 of what is and what is not our body. 9:59:59.000,9:59:59.000 And these self related predictions[br]depend critically on sensory signals 9:59:59.000,9:59:59.000 coming from deep inside the body. 9:59:59.000,9:59:59.000 And finally, 9:59:59.000,9:59:59.000 experiences of being an embodied self[br]are more about control and regulation 9:59:59.000,9:59:59.000 than figuring out what's there. 9:59:59.000,9:59:59.000 So our experiences of the world[br]around us and ourselves within it -- 9:59:59.000,9:59:59.000 well, they're kinds[br]of controlled hallucinations 9:59:59.000,9:59:59.000 that have been shaped[br]over millions of years of evolution 9:59:59.000,9:59:59.000 to keep us alive in worlds[br]full of danger and opporunity. 9:59:59.000,9:59:59.000 We predict ourselves into existence. 9:59:59.000,9:59:59.000 Now I leave you with three[br]implications of all this. 9:59:59.000,9:59:59.000 First, just as we can[br]misperceive the world, 9:59:59.000,9:59:59.000 we can misperceive ourselves 9:59:59.000,9:59:59.000 when the mechanisms[br]of prediction go wrong. 9:59:59.000,9:59:59.000 Understanding this opens many new[br]opportunities in psychiatry and neurology, 9:59:59.000,9:59:59.000 because we can finally[br]get at the mechanisms 9:59:59.000,9:59:59.000 rather than just treating the symptoms 9:59:59.000,9:59:59.000 in conditions like[br]depression and schizophrenia. 9:59:59.000,9:59:59.000 Second: 9:59:59.000,9:59:59.000 what it means to be me cannot be[br]reduced to or uploaded to 9:59:59.000,9:59:59.000 a software program running on a robot, 9:59:59.000,9:59:59.000 however smart or sophisticated. 9:59:59.000,9:59:59.000 We are biological, flesh-and-blood animals 9:59:59.000,9:59:59.000 whose conscious experiences[br]are shaped at all levels 9:59:59.000,9:59:59.000 by the biological mechanisms[br]that keep us alive. 9:59:59.000,9:59:59.000 Just making computers smarter[br]is not going to make the sentient. 9:59:59.000,9:59:59.000 Finally, 9:59:59.000,9:59:59.000 our own individual inner universe, 9:59:59.000,9:59:59.000 our way of being conscious, 9:59:59.000,9:59:59.000 is just one possible[br]way of being conscious. 9:59:59.000,9:59:59.000 And even human consciousness generally -- 9:59:59.000,9:59:59.000 it's just a tiny region in a vast space[br]of possible consciousnesses. 9:59:59.000,9:59:59.000 Our individual self and worlds[br]are unique to each of us, 9:59:59.000,9:59:59.000 but they're all grounded 9:59:59.000,9:59:59.000 in biological mechanisms shared[br]with many other living creatures. 9:59:59.000,9:59:59.000 Now, these are fundamental changes[br]in how we understand ourselves, 9:59:59.000,9:59:59.000 but I think they should be celebrated, 9:59:59.000,9:59:59.000 because as so often in science, 9:59:59.000,9:59:59.000 when Copernicus -- 9:59:59.000,9:59:59.000 we're not at the center[br]of the universe -- 9:59:59.000,9:59:59.000 to Darwin -- 9:59:59.000,9:59:59.000 we're related to all other creatures -- 9:59:59.000,9:59:59.000 to the present day. 9:59:59.000,9:59:59.000 With a greater sense of understanding 9:59:59.000,9:59:59.000 comes a greater sense of wonder, 9:59:59.000,9:59:59.000 and a greater realization that we[br]are part of and not apart from 9:59:59.000,9:59:59.000 the rest of nature. 9:59:59.000,9:59:59.000 And when the end of consciousness comes, 9:59:59.000,9:59:59.000 there's nothing to be afraid of. 9:59:59.000,9:59:59.000 Nothing at all. 9:59:59.000,9:59:59.000 Thank you. 9:59:59.000,9:59:59.000 (Applause)