HALLUCINATION BY BRAIN

You may have heard about Anesthesia - it is a modern kind of magic, it turns people into objects and then, people hope back again into people and in this process is one of the greatest remaining mysteries in science and philosophy. How does consciousness happen? Somehow, within each of our brains, the combined activity of many billions of neurons, each one a tiny biological machine, is generating a conscious experience and not just any conscious experience, your conscious experience right here and right now. How does this happen? Answering this question is so important because consciousness for each of us is all there is. Without it there is no world, there is no self, there is nothing at all. When we suffer, we suffer consciously whether it is thought mental illness or pain. If we can experience joy and suffering, what about other animals? Might they be conscious, too? Do they also have a Spence of self? As computers get faster and smarter maybe there will come a point maybe not too far away when my iPhone develops a Spence of its own existence. I actually think the prospects for a conscious AI are pretty remote. I think this because Anil Seth's research is telling me that consciousness has less to do with pure intelligence and more to do with our nature as living and breathing organisms. Consciousness and intelligence are very different things you don't have to be smart to suffer but you probably do have to be alive. In this topic, I'm going to tell you, our conscious experiences of the world around us, and of ourselves within it, are kinds of controlled hallucinations that happen with, through and because of our living bodies. You might have heard that we know nothing about how the brain and body give rise to consciousness Some people even say it is beyond the reach of science altogether. But in fact, the last 25 years have seen an explosion of scientific work in this area.N ow The question is how consciousness happens and what happens when it goes wrong. The strategy is very simple. I'd like you to think about consciousness in the way that we've come to think about life. At one time, people thought the property of being alive could not be explained by physicians and chemistry, that life had to be more than just mechanism. But people No longer think that as biologists got on with the job of explaining the properties of living systems in terms of physics and chemistry, things like metabolism reproduction, homeostasis the basic mystery of what life is started to fade away and people didn't propose any more magical solutions, like a fore of life or an élan vital, So as with life, so with consciousness. Once we start explaining its properties in terms of thinking happening inside brains and bodies, the apparent insoluble mystery of what consciousness is should start to fade away. At least that is the plan. So let's get started. What are the properties of consciousness? What should a science of consciousness try to explain? Well, for today I'd just like to think of consciousness in two different ways. There are experiences of the world around us, full of sights, sounds, and smells; there is multi-sensory, panoramic 3D, fully immersive inner movie. Then there is conscious self, the specific experience of being you or being me. The lead character in this movie and probably the aspects of consciousness we all cling to most tightly. Let's start experiences of the world around us and with the important idea of the brain as a prediction engine. Imagine being a brain. You're locked inside a bony skull, trying to figure out what is out there in the world. There is no light inside the skull. There is no sound either. All you've got on is streams of electrical impulses which are only indirectly related to things in the world, whatever they may be. So perception figuring out what is there has to be a process of informed guesswork in which the brain combines these sensory signals with its prior expectations or beliefs about the way the world is to form its best guess of what caused those signals, the brain doesn't hear sounds or see light. What we perceive is its best guess of what is out there in the world. Instead of perception depending largely on signals coming into the brain it depends as much if not more, on perceptual predictions flowing in the opposite direction. We don't just passively perceive the world m we actively generate it. The world we experience comes as much, if not more, from the inside out as from the outside in. If hallucination is a kind of uncontrolled perception, then perception right here and right now is also a kind of hallucination, but a controlled hallucination in which the brain's predictions are being reined in by sensory information’s from the world. In fact, we're all hallucinating all the time, including right now. It is just that when we agree about our hallucinations, we call that reality (sounds funny).            Now I am going to tell you that your experience of being a self, the specific experience of being you is also a controlled hallucination generated by the brain, This may seem a very strange idea, yes, visual illusions might deceive my eyes, but how could I be deceived about what it means to be me? For most of us, the experience of being a person is so familiar, so unified and so continuous that it is difficult not to take it for granted. But we shouldn't take it for granted. There are in fact many different ways we experience being a self. There is the experience of having a body and of being a body. There are experiences of perceiving the world from a first-person point of view. There are experiences of intending to do things and of being the cause of things that happen in the world. Their experiences are of being a continuous and distinctive person over time built from a rich set of memories and social interactions. Many experiment show and psychiatrists and neurologists know very well, that these different ways in which we experience being a self can all come apart. What this means is the basic background experience of being a unified self is a rather fragile construction of the brain. Another experience which just likes all others requires explanation. So let's return to the bodily self. How does the brain generate the experience of being a body and of having a body? Well, just the same principles apply, the brain makes its best guess about what is and what is not part of its body. There is a beautiful experiment in neuroscience to illustrate this and unlike most neuroscience experiment; this is one you can do at home. All you need is a rubber had with a forearm and a couple of paintbrushes, it is called Rubber Hand illusion in which a person's real hand is hidden from view and the fake rubber hand is placed in front of them. Then both hands are simultaneously stroked with a paintbrush while the person stares at the fake hand. Now, for most people, after a while, this leads to the very uncanny sensation that the fake hand is, in fact, part of their body. The idea is that the congruence between seeing touch and feeling a touch on an object that looks like a hand and is roughly where a hand should be is enough evidence for the brain to make its best guess that the fake hand is, in fact, part of the body. This means that even experience of what our body is, is a kind of best guessing, a kind of controlled hallucination by the brain. There is one more thing we don't just experience our bodies an objects in the world from outside, we also experience them from within. We all experience the Spence of being a body from the inside. Sensory signals coming from the inside of the body are continually telling the brain about the state of the internal organs, how the heart is doing, what the blood pressure is like lots of things. This kind of perception, which we call interception, is rather overlooked. But it is critically important because perception and regulation of the internal state of the body well, that is what keeps us alive. There is another version of the rubber hand illusion experiment in which people see a virtual reality version of their hand which flashes red and back, either in time or out of time with their heartbeat. When it is flashing in time with their heartbeat people have a stronger sense that it is, in fact, part of their body. So the experience of having a body is deeply grounded in perceiving our body from within. There is one last thing I want to draw your attention to which is that experiences of the body from the inside are very different from experiences of the world around us. When I look around me the world seems full of objects tables, chair, rubber hands, people even my own body in the world. I can perceive it as an object from the outside. But my experiences of the body from within, they are not like that at all. I don't perceive my kidneys, my liver, my spleen etc at their places. I don't perceive my inside as objects. In fact, I don't experience them much at all unless they go wrong. This is important, I think. Perception of the internal state of the body isn't about figuring out what's there; it is about control and regulation, keeping the physiological variables within the tight bounds that are compatible with survival. When the brain uses predictions to figure out what is there, we perceive objects as the causes of sensation. When the brain uses predictions to control and regulate things, we experience how well or how badly that control is going. So our most basic experiences of being a self, of being an embodied organism, are deeply grounded in the biological mechanisms that keep us alive. When we follow this idea all the way through, We can start to see that all of our conscious experiences, since they all depend on the same mechanisms of predictive perception, all stem from this basic drive to stay alive. We experience the world and ourselves with, through and because of our living bodies.Let me bring things together step-by-step. What we consciously see depends on the brain's best guess of what is out there. Our experienced world comes from the inside out, not just outside in. The rubber hand illusion shows that this applies to our experiences of what is and what is not our body. These self-related predictions depend critically on sensory signals coming from deep inside the body and finally, experiences of being an embodied self are more about control and regulation than figuring out what is there. So our experiences of the world around us and ourselves within it well, they're kinds of controlled hallucinations that have been shaped over millions of years of evolution to keep us alive in worlds full of danger and opportunity. We predict ourselves into existence. Now, I would like to end up this topic with three implications of all this. First, just as we can misperceive the world, we can misperceive ourselves when the mechanisms of prediction go wrong. Understanding this opens many new opportunities in psychiatry and neurology because we can finally get at the mechanisms rather than just treating the symptoms in conditions like depression and schizophrenia. Second, what it means to be me cannot be reduced to or uploaded to a software program running on a robot, however smart or sophisticated. We are biological, flesh-and-blood animals whose conscious experiences are shaped at all levels by the biological mechanisms that keep us alive. Just making computers smarter is not going to make them sentient. Finally, our own individuals’ inner universe our way of being conscious is just one possible way of being conscious. Even human consciousness generally, it is just a tiny region in a vast space of possible consciousnesses. Our individual self and worlds are unique to each of us but they're all grounded in biological mechanisms shared with many other living creatures. Now, these are fundamental changes in how we understand ourselves but I think they should be celebrated because as so often in science from Copernicus we're not at the center of the universe to Darwin we're related to all other creatures to the present day. With a greater sense of understanding come a greater sense of wonder and a greater realization that we are part of and not apart from the rest of nature and when the end of consciousness comes there is nothing to be afraid of nothing at all.