Your brain hallucinates your conscious reality | Anil Seth

Your brain hallucinates your conscious reality | Anil Seth


Just over a year ago, for the third time in my life,
I ceased to exist. I was having a small operation,
and my brain was filling with anesthetic. I remember a sense
of detachment and falling apart and a coldness. And then I was back,
drowsy and disoriented, but definitely there. Now, when you wake from a deep sleep, you might feel confused about the time
or anxious about oversleeping, but there’s always a basic sense
of time having passed, of a continuity between then and now. Coming round from
anesthesia is very different. I could have been under
for 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 self? And as computers get faster and smarter, maybe there will come a point,
maybe not too far away, when my iPhone develops
a sense of its own existence. I actually think the prospects
for a conscious AI are pretty remote. And I think this because
my 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 the story 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. Now, you might have heard
that we know nothing about how the brain and body
give rise to consciousness. Some people even say it’s beyond
the reach of science altogether. But in fact, the last 25 years have seen an explosion
of scientific work in this area. If you come to my lab
at the University of Sussex, you’ll find scientists
from all different disciplines and sometimes even philosophers. All of us together trying to understand
how consciousness happens and what happens when it goes wrong. And 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 physics 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 force of life or an élan vital. So as with life, so with consciousness. Once we start explaining its properties in terms of things happening
inside brains and bodies, the apparently insoluble mystery
of what consciousness is should start to fade away. At least that’s 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’s multisensory, panoramic,
3D, fully immersive inner movie. And then there’s conscious self. The specific experience
of being you or being me. The lead character in this inner movie, and probably the aspect of consciousness
we all cling to most tightly. Let’s start with 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
what’s out there in the world. There’s no lights inside the skull.
There’s no sound either. All you’ve got to go 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’s 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 sound or see light. What we perceive is its best guess
of what’s out there in the world. Let me give you a couple
of examples of all this. You might have seen this illusion before, but I’d like you to think
about it in a new way. If you look at those two patches, A and B, they should look to you to be
very different shades of gray, right? But they are in fact
exactly the same shade. And I can illustrate this. If I put up a second version
of the image here and join the two patches
with a gray-colored bar, you can see there’s no difference. It’s exactly the same shade of gray. And if you still don’t believe me, I’ll bring the bar across
and join them up. It’s a single colored block of gray,
there’s no difference at all. This isn’t any kind of magic trick. It’s the same shade of gray, but take it away again,
and it looks different. So what’s happening here is that the brain
is using its prior expectations built deeply into the circuits
of the visual cortex that a cast shadow dims
the appearance of a surface, so that we see B as lighter
than it really is. Here’s one more example, which shows just how quickly
the brain can use new predictions to change what we consciously experience. Have a listen to this. (Distorted voice) Sounded strange, right? Have a listen again
and see if you can get anything. (Distorted voice) Still strange. Now listen to this. (Recording) Anil Seth: I think Brexit
is a really terrible idea. (Laughter) Which I do. So you heard some words there, right? Now listen to the first sound again.
I’m just going to replay it. (Distorted voice) Yeah? So you can now hear words there. Once more for luck. (Distorted voice) OK, so what’s going on here? The remarkable thing is the sensory
information coming into the brain hasn’t changed at all. All that’s changed
is your brain’s best guess of the causes of that sensory information. And that changes
what you consciously hear. All this puts the brain
basis of perception in a bit of a different light. Instead of perception depending largely
on signals coming into the brain from the outside world, it depends as much, if not more, on perceptual predictions
flowing in the opposite direction. We don’t just passively
perceive the world, we actively generate it. The world we experience
comes as much, if not more, from the inside out as from the outside in. Let me give you
one more example of perception as this active, constructive process. Here we’ve combined immersive
virtual reality with image processing to simulate the effects
of overly strong perceptual predictions on experience. In this panoramic video,
we’ve transformed the world — which is in this case Sussex campus — into a psychedelic playground. We’ve processed the footage using
an algorithm based on Google’s Deep Dream to simulate the effects
of overly strong perceptual predictions. In this case, to see dogs. And you can see
this is a very strange thing. When perceptual
predictions are too strong, as they are here, the result looks very much
like the kinds of hallucinations people might report in altered states, or perhaps even in psychosis. Now, think about this for a minute. 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 from the world. In fact, we’re all
hallucinating all the time, including right now. It’s just that when we agree
about our hallucinations, we call that reality. (Laughter) Now I’m 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 seems a very strange idea, right? 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’s 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’s 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. And there are experiences of being a continuous
and distinctive person over time, built from a rich set
of memories and social interactions. Many experiments 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 like 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. And there’s a beautiful experiment
in neuroscience to illustrate this. And unlike most neuroscience experiments, this is one you can do at home. All you need is one of these. (Laughter) And a couple of paintbrushes. In the rubber hand illusion, a person’s real hand is hidden from view, and that 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. And the idea is that the congruence
between seeing touch and feeling touch on an object that looks like 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. (Laughter) So you can measure
all kinds of clever things. You can measure skin conductance
and startle responses, but there’s no need. It’s clear the guy in blue
has assimilated the fake hand. This means that even experiences
of what our body is is a kind of best guessing — a kind of controlled
hallucination by the brain. There’s one more thing. We don’t just experience our bodies
as objects in the world from the outside, we also experience them from within. We all experience the sense
of being a body from the inside. And 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 interoception, is rather overlooked. But it’s critically important because perception and regulation
of the internal state of the body — well, that’s what keeps us alive. Here’s another version
of the rubber hand illusion. This is from our lab at Sussex. And here, people see
a virtual reality version of their hand, which flashes red and back either in time or out of time
with their heartbeat. And when it’s flashing
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 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’s out there. Our experienced world
comes from the inside out, not just the outside in. The rubber hand illusion shows
that this applies to our experiences of what is and what is not our body. And 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’s 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 leave you 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 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 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 comes 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’s nothing to be afraid of. Nothing at all. Thank you. (Applause)

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  1. Thats how it looks, when you get lost on a completely wrong path. There is no self and the world. Thats also just an illusion the brain creates. There is only conciousness and conciousness is prior to everything. Conciousness doesnt get created, conciousness creates everything. The brain trying to figure out what conciousness is, is like a hammer trying to figure out, what swings it by looking at the nail. The approach of Anil Seth is hopelessly bound to end up in frustration.

  2. I was recently on a flight from Thailand and as I slept I dreamt that I was driving my car and a rocket was flying overhead. I believe because of the roar of the aircrafts engines my mind used its best guess to determine the source of this sound and expressed this as the rocket in the dream

  3. I LOVE general anesthetic. I would elect to do it every few months just for the rest. Of course every animal is conscious.

  4. "When the end of consciousness comes, there is NOTHING to be afraid of" Based on everything you just said, which was extremely smart, until you got to this part, it became contradictory. You have no way of knowing that. You can create ways of knowing it, but the unfiltered, non-hallucinated truth will remain as it is.

  5. You couldn't be more WRONG about life not being due to some life force essence. It's called the SPIRIT, and without it, the body is completely dead, even though that body still has ALL of the DNA and Neural Networks and chemistry it had before death! What's the difference? Simple, a living body has this mystical life force "SPIRIT" The dead body does not! If as you claim science knows life is simply due to chemical motion then we should have created life in a laboratory by now, and yet, brilliant scientists have attempted and failed to this present time even to create the simplest life through chemistry…it isn't Chemistry that is the spark of life…it is the SPIRIT! The most we have ever made in lab were very basic amino acids and they were all of the right handed type, yet in biological organisms all amino acids are of the left handed type, so even the basic amino acids created in lab were the completely wrong types! Again…WITHOUT THE SPIRIT (True source of consciousness and awareness of self) There is NO LIFE even with all the necessary chemistry present and even put together! By the way consciousness is NOT dependent upon having a body either. Consciousness doesn't end, because it's source is eternal…therefore it also is eternal.

  6. If I had a nickel for every Jewish shill who claims there is no reality, I might be as rich as they are. If you believe you are not supposed to believe your own God-given five senses, there is no hope for you.

  7. See I know we have more planets in our solar system. I know that Jesus Christ is still alive protected from time by GOD'S light. I know GOD isn't "his" real name. I know GOD stretched out the heavens over the earth like a tint and I don't have to know the numbers of the clouds by wisdom because I GOD knows its for me. I know what dreams are. And entites that walk pass my face. Secrets gave to me from the deer🦌 with a crown on its head stirring in to my soul. Thou knowest thy foundations of earth or the corner stones and the pilers of the earth. The number of firmaments. The tests that were done. Energy electricity all levels of all levels. The connection to that electricity and to one another. I'm tiered of being smarter. I hate when I get lied to. Jesus Christ is the one who showed me the truth. Sed everyone would hate me because he choose me out of this world and because he is not of this world they will hate him. And will hate me but know that they hated him first.😇🙏

  8. How do we know this is true? I mean his brain is telling him to say these things. His brain is basically trying to explain his brain???

  9. No, your brain does not hallucinate reality. The mainstream science has become full of priest physics and pedophile thinking. These buffoons should never be allowed a platform to let their stupidity manifest itself. Only a complete and utter douche bag would state such idiocy. The buffoonery taking place is astounding and unfathomable. If anyone believes this garbage coming out TEdx lol then you all deserve it.

  10. Consciousness is a place where self meets peace and understanding then begins its journey by reacting with enlightenment awakening to its sense of truth and establishing its ways of natural abilities .
    Be Blessed !

  11. Haven’t watched it yet. But the headline is kind of true. We are in a virtual existence. Nothing is solid. Just through perception

  12. When the end of consciouness comes, theres nothing to be afraid of… Sent chills through my body. Im no longer afraid of death after today.

  13. see…this is where you're completely wrong, consciousness has nothing to do with animate matter….being alive is a result but not a law of existence. IT is existence that is conscious not life. Living tissue is a subgroup of reality. EGGis10nce is the primacy, not consciousness. A stone in a lake is ABSOLUTELY conscious BECAUSE it exists. HUMANS are surrounded by existence. I once felt great empathy for my dads car when it was over heated and that big V8 engine spoke to me…it was tearful to me. I could PERCEIVE its EGGis10nce

  14. What I learned so far:

    Anil Seth: "Nothing is real".
    Sam Harris: "There is no free will".
    VSauce: "You can't touch anything".

    So… Nothing is true and everything is permitted?

    Ordo ab chao?

    Prima materia?

    Morphic resonance?

    The universe within us?

    Sorry… Too much weed for me. >_>

  15. I've often thought that I'm the only thing in the universe and all else is just an hallucination!
    Funny thing is.. I've no way to disprove this notion!

  16. I like listening to his knowledge regarding consciousness but how does he know with such certainty that there is Nothing To Be Afraid Of when we die?

  17. Me: hand over ears and eyes closed saying lalalalalalalalal
    Second hand on clock:🕧 10 sec later
    Me again with memory of Gollum/Smeagol It's still talking!! 😖

  18. The brain does not produce any reality whatsoever. Reality is of the mind. The brain and the body are inside the mind, not the other way around. The body is fictional. The mind hallucinates, not the body. In fact the brain and body are an hallucination. The brain is just an interface for the mind to translate intentions into the body. The mind uses the body, the body does not use the mind. There is way too much idol worship of the lump of fat between your ears. It is not that important.

  19. it’s said that a person can hallucinating the whole thing but when another person witnesses another person’s hallucination its considered reality

  20. Row Row Row your boat down the mother fucking stream, yep yep yeah life is just another fucking dream. -2019 version.

  21. Here is the problem with this theory: If it is a true fact about reality that we are all hallucinating a false representation of reality, then this fact is something about the true reality that is known to us. Ergo, our knowledge of reality is not entirely illusory, and we can have actual knowledge of reality as it exists independently of our hallucinations.

    There is also a problem with this claim: "We're all hallucinating all the time; when we agree about our hallucinations, we call it 'reality'." The problem being that other people's "agreement" would also be just a part of my hallucination. Therefore, if I hallucinate myself to be a 17th century samurai, then I literally am one provided everyone in my hallucination says so.

    Better luck next time, Anil Seth. Maybe try reading a few logic or philosophy books before presenting your next theory.

  22. His Analogy is since Brain is ultimately hallucinating the experience around it so the brain is also hallucinating the consciousness which is the first person experience. Now the difference between hallucinating and I who is hallucinating is not the same. He is trying to make a brute force argument that consciousness is ultimately a illusion but he never mentions about the mysterious that i experience that hallucination, where is that i comes from …. hallucination again. There is a gap in the understanding, now he made consciousness more mysterious.

  23. This doesn't explain conciousness at all. So what if the brain is hallucinating many parts our personal concious experience of "self"? The bigger question is why is there anyone there to observe it? It doesn't explain how we have a first-person perspective.

  24. Think about this: how do we know, when we see a particular color, that that particular color looks the same to someone else? You were always told blue was what you see as blue but to someone else, their blue might look red, but they have always been told that what they see as red was blue.

    Can anyone else understand this theory?

  25. Be sure to read honest and real reviews left by users who have bought Mind Reality on my blog before you buy. Go to thecbreviews. com/mind-reality-review/ (remove space before com). Thanks, Sergeant.

  26. Consciousness: A thing in itself, or besides itself, the sum of all qualia, or perhaps a channel on the Matrix. Consciousness can be raised, lowered, embodied, or if it means to, float out of this room. It is everywhere, perhaps nowhere, but most certainly is here with you, reading this dumb definition, and is well, self-conscious about it.
    from Dr. Mezmer’s World of Bad Psychology, found on an internet near you

  27. Your not actually changing reality you just trick your brain into thinking something is happening when it’s not because we are not finally tuned machines our body’s aren’t perfect

  28. Panpsychism(law of mentalism in hermetics) and your dna is a fractal antenna. Your brain doesn't hallucinate consciousness it creates it with scalar waves.

  29. "Now I actually think that the prospects for a conscious AI are pretty remote; and I think this because-" *proceeds to spend 15 minutes explaining how perception works as a biological function and that it's guesswork, and 'reality is just what we agree on' and claiming that this is an exclusive byproduct of us being living things. Even though none of this has any correlation to AI achieving sapience. Literally this lecture is "AI can't be conscious because we all hallucinate reality." The latter is scientific fact and neato burrito, but there's not even a remote correlation there. Why would us hallucinating reality magically block machines from gaining the ability to perceive reality as sentient beings?

  30. In other words, you consciously perceive your conscious reality. These consciousness studies folks are fraudsters, the modern snake oil salesmen of philosophy. If you are not going to even attempt to solve the hard problem you are not studying consciousness, you are just doing neural correlates.

  31. My phone is a smart phone it has a mind of its own !! It does what it wants , it freezes when I am trying to write , or watch videos !!

  32. "We're all hallucinating all the time, including right now. It's just that when we agree about our hallucinations, we call that reality.
    "

  33. As often in science, from Copernicus "we're not at the centre of the universe" to Darwin "we're related to all other creatures" to the present day [consciousness is grounded in biological mechanisms shared with many other living creatures], with a greater sense of understanding comes a greater sense of wonder, and a greater realisation that we are part of and not apart from the rest of nature.

  34. Who's to say the person that wakes up from anesthesia is the same person … who's to say any of us are really more than consciousness in the moment deceived into believing our memories are us..

  35. Of course the "guy in blue" would react like that. If you were sitting there and someone lunged toward you with a sharp object you should react.

  36. 1:55 Conscious AI is definitely remote because of the reasoning he gives here. It's the same reason heavier than air flying machines are impossible, because flying has less to do with Physics than with the biology of flying such as is possessed by birds and insects.

  37. I m here, living my retarded life and wasting more oxygen in this world for no reason because of " Fractured " movie.

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