Your Brain Hallucinates Your Conscious Reality | Anil Seth | TED

This segment introduces the speaker's methodology for understanding consciousness, drawing a parallel between the historical shift in understanding life as a purely mechanistic process and the potential for a similar shift in understanding consciousness. The speaker proposes that by explaining the properties of consciousness through the lens of brain and body processes, the mystery of consciousness can be demystified. This segment explains the brain's role in constructing our perception of reality. The speaker argues that perception is not a passive reception of sensory input but an active process of informed guesswork, where the brain combines sensory signals with prior expectations to form its best guess about the external world. The speaker uses the example of visual illusions to illustrate this point. This segment builds upon the previous segment, proposing that perception is essentially a controlled hallucination. The speaker uses examples from virtual reality experiments and altered states of consciousness to show how strong perceptual predictions can lead to hallucinations. The segment concludes with the provocative idea that our shared hallucinations constitute our reality.This segment extends the concept of controlled hallucination to the experience of self. The speaker argues that our sense of self, including our bodily self, is also a construction of the brain, a best guess based on sensory input and prior expectations. The rubber hand illusion is used as an example to demonstrate how easily the brain can be tricked into accepting a false body part as its own. in time with their heartbeat, people have a stronger sense that it's in fact part of their body. so experiences of having a body are deeply grounded in perceiving our bodies from within. there's 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, chairs, rubber hands, people, you lot --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're not like that at all. I don't perceive my kidneys here, my liver here, my spleen ... I don't know where my spleen is, but it's somewhere. I don't perceive my insides as objects. in fact, I don't experience them much at all unless they go wrong. and this is important, I think. perception of the internal state of the body isn't about figuring out what's there, it's 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's there, we perceive objects as the causes of sensations. 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. and when we follow this idea all the way through, we can start to five minutes, five hours, five years or even 50 years. I simply wasn't there. it was total oblivion. anesthesia --it's a modern kind of magic. it turns people into objects, and then, we 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's no world, there's no self, there's nothing at all. and when we suffer, we suffer consciously whether it's through mental illness or pain. and if we can experience joy and suffering, what about other animals? might they be conscious, too? do they also have a sense of 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 individual inner universe, our way of being conscious, is just one possible way of being conscious. and even human consciousness generally --it's 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