0:00:02 > 0:00:05This programme contains some scenes which some viewers may find upsetting
0:00:05 > 0:00:07Over the last 100,000 years, our species has been on quite a ride.
0:00:07 > 0:00:10We've gone from primitive hunter-gatherers
0:00:10 > 0:00:13poking around for scraps
0:00:13 > 0:00:16to a world-conquering, city-dwelling,
0:00:16 > 0:00:18hyper-connected super-species,
0:00:18 > 0:00:22and it's all thanks to the three pounds of wet biological
0:00:22 > 0:00:25material stored up here.
0:00:25 > 0:00:29We live surrounded by our inventions.
0:00:29 > 0:00:33We have the means to travel, to make,
0:00:33 > 0:00:38to communicate, to build.
0:00:38 > 0:00:42What I find incredible is that all of this was built with
0:00:42 > 0:00:46the same neural material that our ancestors used to hunt
0:00:46 > 0:00:48and to build primitive tools.
0:00:48 > 0:00:52The genius of Mother Nature and the secret to her success
0:00:52 > 0:00:56was to build a brain that could innovate,
0:00:56 > 0:01:00to make the journey from primitive man to this
0:01:00 > 0:01:04in a very short amount of time.
0:01:04 > 0:01:07I want to explore what it is about the brain
0:01:07 > 0:01:11that's made this journey possible.
0:01:11 > 0:01:15If we can understand how it works,
0:01:15 > 0:01:19then maybe we can direct its power in new ways
0:01:19 > 0:01:23and open a new chapter in the human story.
0:01:27 > 0:01:29So what's next for our brains?
0:01:29 > 0:01:33What do the next 1,000 years have in store for us?
0:01:33 > 0:01:37And in the far future, what is the human race going to look like?
0:01:37 > 0:01:39What will we be capable of?
0:01:42 > 0:01:46This is a journey into who we might become.
0:01:47 > 0:01:50We'll look at how we can use our brains
0:01:50 > 0:01:52to control new kinds of bodies.
0:01:55 > 0:01:57ROBOT HAND BUZZES
0:01:57 > 0:02:04How our sensory experience can be expanded to new horizons.
0:02:04 > 0:02:07We'll look at how we might one day separate our minds
0:02:07 > 0:02:10from our physical selves -
0:02:10 > 0:02:14even possibly overcome death.
0:02:41 > 0:02:45The human body - it's a masterpiece of complexity and beauty.
0:02:45 > 0:02:51It's a symphony of 40 trillion cells all operating in concert,
0:02:51 > 0:02:58and it's all orchestrated by the three-pound organ we call the brain.
0:02:58 > 0:03:01Sensory information floods in.
0:03:01 > 0:03:03Decisions are made.
0:03:03 > 0:03:06Responses are formulated.
0:03:06 > 0:03:12The brain sends out commands and the body moves into action,
0:03:12 > 0:03:16but what if the brain could do more - handle more?
0:03:16 > 0:03:21What if there were other ways for it to operate?
0:03:21 > 0:03:25We're heading for a fundamental change in the relationship
0:03:25 > 0:03:29between the body, the brain and the outside world.
0:03:29 > 0:03:33We're marrying our biology with our technology
0:03:33 > 0:03:37and that's poised to transform who we will be.
0:03:40 > 0:03:44This is all possible thanks to a special property of the brain
0:03:44 > 0:03:47called "plasticity".
0:03:47 > 0:03:51It's best illustrated through a remarkable story.
0:03:57 > 0:04:00Meet Cameron Mott.
0:04:00 > 0:04:03In this home movie, she's four years old.
0:04:03 > 0:04:06I'm a princess girl, Daddy!
0:04:06 > 0:04:08A princess girl!
0:04:08 > 0:04:11I'm a princess girl.
0:04:11 > 0:04:15One day, Cameron suddenly started having seizures.
0:04:15 > 0:04:18SHE GROANS
0:04:18 > 0:04:21The really big issue was that Cameron's seizures were
0:04:21 > 0:04:24drop seizures where she would fall down to the floor very quickly
0:04:24 > 0:04:26and they were very aggressive.
0:04:26 > 0:04:28- Cameron... Whoopsie! - SHE SHRIEKS
0:04:28 > 0:04:31She was diagnosed with Rasmussen syndrome,
0:04:31 > 0:04:35an inflammatory disease that attacks the brain.
0:04:35 > 0:04:39It causes paralysis and ultimately death.
0:04:42 > 0:04:44To save Cameron's life,
0:04:44 > 0:04:48her physicians proposed a radical solution.
0:04:48 > 0:04:51They would remove the diseased part of her brain.
0:04:53 > 0:04:54Blow harder.
0:04:54 > 0:04:58'The procedure itself is probably the most drastic surgical procedure
0:04:58 > 0:05:01'that can be done in neurosurgery.'
0:05:01 > 0:05:03You know, it's not a simple operation.
0:05:03 > 0:05:05There are... On a scale of one to ten,
0:05:05 > 0:05:07ten being one of the more difficult operations
0:05:07 > 0:05:10that we would typically perform in neurosurgery,
0:05:10 > 0:05:13I'd say it's a ten.
0:05:13 > 0:05:18Seeing no other option, Cameron's parents consented.
0:05:18 > 0:05:20The real risk in the surgery is not
0:05:20 > 0:05:22what happens if we do the surgery.
0:05:22 > 0:05:23The question is,
0:05:23 > 0:05:26what happens to this person if we don't do the surgery?
0:05:26 > 0:05:29MACHINE BEEPS
0:05:30 > 0:05:37The issue was that an entire half of Cameron's brain had been affected.
0:05:45 > 0:05:47Our biggest concern was, would she survive?
0:05:47 > 0:05:50Would there be some complication?
0:05:50 > 0:05:56Would we go through all of this and then still have seizures at the end?
0:06:02 > 0:06:05This is Cameron's preoperative scan.
0:06:05 > 0:06:10This is the material that underpins her intellect and her emotion,
0:06:10 > 0:06:12and her sense of humour - who she is.
0:06:16 > 0:06:18In this scan, the empty space
0:06:18 > 0:06:22is where half of her brain has been removed.
0:06:22 > 0:06:26No-one could be sure how the loss of that much brain tissue
0:06:26 > 0:06:28would affect Cameron.
0:06:28 > 0:06:30What would she lose?
0:06:30 > 0:06:33Could she be like other children?
0:06:36 > 0:06:39This is Cameron seven years on.
0:06:39 > 0:06:43She's seizure-free,
0:06:43 > 0:06:48and more importantly, beyond a slight weakness on one side,
0:06:48 > 0:06:54she betrays no sign of the ordeal that she went through.
0:06:54 > 0:06:59I like to run a lot and do different types of stuff outside.
0:07:01 > 0:07:03I love math.
0:07:03 > 0:07:08Give me... Give me three quizzes to do and I'll do it.
0:07:08 > 0:07:10OK, let it go.
0:07:13 > 0:07:15Just imagine taking your laptop
0:07:15 > 0:07:19and tearing out half the motherboard and expecting it to still function.
0:07:19 > 0:07:24It would never work with a computer but it can work with a young brain,
0:07:24 > 0:07:28and that has dramatic implications.
0:07:28 > 0:07:33We used to think of the brain as a fixed system, with different parts
0:07:33 > 0:07:38dedicated to specific jobs like seeing or deciding and moving,
0:07:38 > 0:07:42but no region works in isolation.
0:07:42 > 0:07:46The brain is a vast, dynamic, interconnected network
0:07:46 > 0:07:49that's always changing.
0:07:49 > 0:07:55Instead of hard-wired, I like to think of the brain as live-wired,
0:07:55 > 0:07:59and that flexibility of the brain opens up new possibilities
0:07:59 > 0:08:01for our future.
0:08:04 > 0:08:07It could be argued that this future has been with us
0:08:07 > 0:08:14since the 1970s, in the form of a simple piece of technology.
0:08:14 > 0:08:19This is a cochlear implant and it can give hearing to deaf people.
0:08:19 > 0:08:22MACHINE BUZZES It picks up sounds
0:08:22 > 0:08:24and converts them to electrical signals
0:08:24 > 0:08:29that plug directly into the cells of the inner ear.
0:08:29 > 0:08:31Now, when it was first introduced,
0:08:31 > 0:08:33researchers didn't think it was going to work,
0:08:33 > 0:08:38because biology is wired up with such precision and specificity,
0:08:38 > 0:08:42and this just takes crude signals and shoves them into the brain,
0:08:42 > 0:08:45in a way that the brain's not expecting.
0:08:45 > 0:08:50The cochlear implant represents a marriage between metal electrodes
0:08:50 > 0:08:55and biological cells, and yet, it works.
0:08:55 > 0:08:59Around the world, almost 750,000 people have had the chance to
0:08:59 > 0:09:02hear for the first time, thanks to these implants.
0:09:04 > 0:09:07Wow.
0:09:07 > 0:09:09Here's how.
0:09:09 > 0:09:14Whether it comes from your ears or your eyes
0:09:14 > 0:09:15or a touch on your skin...
0:09:17 > 0:09:21..all the information that enters your brain is converted into
0:09:21 > 0:09:25the same stuff - electrochemical signals.
0:09:25 > 0:09:29These are the common currency of the brain.
0:09:30 > 0:09:34When the implant produces these signals, however crudely,
0:09:34 > 0:09:39the brain finds a way to make sense of them.
0:09:39 > 0:09:43It hunts for patterns... BUZZING AND CRACKLING
0:09:43 > 0:09:46..cross-referencing with other senses.
0:09:46 > 0:09:49TRAFFIC RUMBLES
0:09:50 > 0:09:54At first, the signals are unintelligible,
0:09:54 > 0:09:57but soon, meaning emerges. BELL RINGS
0:09:59 > 0:10:03Cochlear implants reveal something amazing about the brain,
0:10:03 > 0:10:07which is whatever signals you feed into it, the brain will figure out
0:10:07 > 0:10:10how to extract something useful out of that.
0:10:10 > 0:10:13As long as the data coming in has a structure that maps onto
0:10:13 > 0:10:18the outside world, the brain will figure out how to decode it,
0:10:18 > 0:10:22and this turns out to be one of nature's greatest tricks.
0:10:22 > 0:10:27And now that we know about it, it opens up a world of possibilities.
0:10:27 > 0:10:32Why restrict ourselves to trying to replace lost or damaged senses?
0:10:32 > 0:10:34There must be ways for us
0:10:34 > 0:10:39to enhance or add to the senses that we already have.
0:10:44 > 0:10:48In my laboratory, we've created this vest.
0:10:48 > 0:10:52It turns sound into patterns of vibration
0:10:52 > 0:10:55that are felt on the skin of the torso.
0:10:57 > 0:11:01'The idea is that, given enough time,
0:11:01 > 0:11:02'the wearer's brain will learn to
0:11:02 > 0:11:06'automatically decode these vibrations.
0:11:06 > 0:11:12'They'll instinctively feel and understand information.'
0:11:12 > 0:11:16This is the alien language game, so you're going to feel a word
0:11:16 > 0:11:19presented to you as a pattern of vibration on your torso.
0:11:19 > 0:11:22Through time, you're going to get better and better at this,
0:11:22 > 0:11:25as your brain starts decoding how these inputs
0:11:25 > 0:11:28map onto words that you know,
0:11:28 > 0:11:32and your job is just to figure out what the language of the vest is.
0:11:32 > 0:11:36I can feel the vibrations on my body. It makes no sense to me.
0:11:36 > 0:11:37They're just random.
0:11:37 > 0:11:39I'm aware that may be one on the left shoulder
0:11:39 > 0:11:42or right shoulder or lower back...
0:11:42 > 0:11:45BELL RINGS
0:11:47 > 0:11:52One of my lab members, Joshua, wore the vest as he went about his day.
0:11:52 > 0:11:56An app sends a pattern of vibrations to his torso.
0:11:56 > 0:12:00He guesses what word that pattern represents
0:12:00 > 0:12:04and he's told whether he's right or wrong.
0:12:04 > 0:12:07'For the first week or so, I mean, it was just total nonsense,
0:12:07 > 0:12:10'to try to figure out which word was just projected onto me,
0:12:10 > 0:12:14'but as time has gone by, I am able to,'
0:12:14 > 0:12:17through some process, distinguish them.
0:12:17 > 0:12:20It seems strange that you could understand information
0:12:20 > 0:12:24through your torso, but that's the surprise -
0:12:24 > 0:12:29it doesn't matter how signals find their way to the brain.
0:12:29 > 0:12:32We have these peripheral senses that we plug in,
0:12:32 > 0:12:35but here's the thing - our eyes, our nose, our mouth -
0:12:35 > 0:12:39these are just what we inherit from our evolutionary past.
0:12:39 > 0:12:43It's what we come to the table with, but we don't have to stick with it,
0:12:43 > 0:12:44because it might be possible
0:12:44 > 0:12:49that we could plug some sensory channel into an unusual port
0:12:49 > 0:12:52into the brain and the brain will just figure it out,
0:12:52 > 0:12:55and it may be that, in the near future,
0:12:55 > 0:12:57we can invent new sorts of sensory devices
0:12:57 > 0:13:00and plug them directly into the brain.
0:13:00 > 0:13:04In theory, there's no limit to the new sensory expansion
0:13:04 > 0:13:06that we can create.
0:13:10 > 0:13:15So, just imagine if we could feed in an input of real-time weather data,
0:13:15 > 0:13:19so you could feel if it's raining 100 miles away
0:13:19 > 0:13:21or if it's going to snow tomorrow.
0:13:24 > 0:13:28THUNDER RUMBLES Or imagine feeding in
0:13:28 > 0:13:32real-time stock data and developing an intuitive sense
0:13:32 > 0:13:34of how the markets were moving.
0:13:34 > 0:13:37You'd be plugged in to the global economy.
0:13:40 > 0:13:44Because of the brain's capacity to take on new inputs,
0:13:44 > 0:13:49we should be able to expand the experience of being human.
0:13:52 > 0:13:55We could enjoy things that wouldn't be possible with
0:13:55 > 0:14:00the traditional senses we arrive with.
0:14:00 > 0:14:05It may be that the evolution of our technology, rather than our
0:14:05 > 0:14:11biology, is what guides the journey of our species from here on out.
0:14:11 > 0:14:13As we move into the future,
0:14:13 > 0:14:17we'll increasingly design our own portals on the world
0:14:17 > 0:14:19and, as far as we can tell, there's no limit
0:14:19 > 0:14:22in what the brain can incorporate.
0:14:22 > 0:14:27Instead, we now have the tools to shape our own sensory experiences -
0:14:27 > 0:14:31to widen our small windows on reality.
0:14:32 > 0:14:37Now, how we sense the world - that's only half the story.
0:14:37 > 0:14:42The other half is how we interact with it.
0:14:42 > 0:14:46What if we could use the brain's flexibility to
0:14:46 > 0:14:51change our physical bodies?
0:14:51 > 0:14:53This is Jan Scheuermann.
0:14:53 > 0:14:57Because of a rare genetic disease, the spinal-cord nerves that
0:14:57 > 0:15:03connect her brain to her muscles have deteriorated.
0:15:03 > 0:15:06I can't move anything below my neck.
0:15:06 > 0:15:09Though the stem of my brain meets my spinal-cord,
0:15:09 > 0:15:12there's some deterioration there,
0:15:12 > 0:15:14then the signals aren't getting through
0:15:14 > 0:15:18so my brain is saying, "Lift up," to my arm,
0:15:18 > 0:15:21and my arm is saying, "I can't hear you!"
0:15:23 > 0:15:28Now Jan is participating in a trailblazing experiment -
0:15:28 > 0:15:32part neurosurgery, part robotics.
0:15:32 > 0:15:37Two electrode arrays implanted into her brain provide
0:15:37 > 0:15:40a link from her motor cortex to this -
0:15:40 > 0:15:44the world's most advanced robotic arm.
0:15:44 > 0:15:47ROBOTIC ARM BUZZES AND HUMS
0:15:47 > 0:15:50OK. Up. Down.
0:15:53 > 0:15:56Its fingers can curl and uncurl.
0:15:56 > 0:15:58It can roll.
0:15:58 > 0:16:00The wrist can flex.
0:16:00 > 0:16:05Jan can control it just by thinking about it.
0:16:05 > 0:16:09Right...
0:16:09 > 0:16:11and grasp.
0:16:11 > 0:16:15Though she speaks the commands out loud, she has no need to.
0:16:15 > 0:16:18- Back to me. - There's a direct physical link
0:16:18 > 0:16:21between the arm and her brain.
0:16:21 > 0:16:22Down.
0:16:24 > 0:16:26An arm normally moves
0:16:26 > 0:16:29because of a storm of activity in the motor cortex.
0:16:29 > 0:16:33From there, the signals travel down the spinal-cord to
0:16:33 > 0:16:36the muscles of the arm.
0:16:36 > 0:16:42In Jan's case, electrodes eavesdrop on the cortical signals directly
0:16:42 > 0:16:46and redirect those to Hector, her new arm.
0:16:51 > 0:16:53Like riding a bicycle,
0:16:53 > 0:16:56the brain doesn't forget how to move the arm,
0:16:56 > 0:16:59even though it hasn't moved in ten years.
0:17:01 > 0:17:06With practice, this relationship will become fully unconscious.
0:17:06 > 0:17:09She'll be able to move Hector automatically
0:17:09 > 0:17:11without thinking about it,
0:17:11 > 0:17:13just as we do with our biological limbs.
0:17:18 > 0:17:20Oh, it feels very good to be able to shake hands
0:17:20 > 0:17:24and fist-bump and interact.
0:17:24 > 0:17:27It's so very life-affirming to me,
0:17:27 > 0:17:29to be able to reach out and touch a person.
0:17:32 > 0:17:35Jan's experience points to a future in which
0:17:35 > 0:17:39we use technology to enhance and extend our bodies,
0:17:39 > 0:17:44not only replacing limbs or organs but improving them,
0:17:44 > 0:17:50elevating them, from human fragility to indestructibility.
0:17:52 > 0:17:56Hollywood has often imagined a person who is part machine -
0:17:56 > 0:17:59well, that fantasy is fast becoming real.
0:17:59 > 0:18:01ARM BUZZES
0:18:12 > 0:18:15As we learn how to take on new sensory experiences
0:18:15 > 0:18:18and control new kinds of bodies,
0:18:18 > 0:18:21that's going to profoundly change who we are as individuals,
0:18:21 > 0:18:25and that's because our physicality sets the tone
0:18:25 > 0:18:28for how we feel and how we think, and who we are.
0:18:28 > 0:18:32At this moment in history, it may be that we have more in common with our
0:18:32 > 0:18:38Stone Age ancestors than we do with our descendants in the near future.
0:18:43 > 0:18:48We're already beginning to extend the human body, but no matter how
0:18:48 > 0:18:51much we enhance ourselves, there's something we need to keep in mind.
0:18:51 > 0:18:54Our body is made of flesh and bones.
0:18:54 > 0:18:57It's going to deteriorate and die,
0:18:57 > 0:19:01but what if the study of the brain could address our mortality?
0:19:01 > 0:19:04What if, in the future, we didn't have to die?
0:19:10 > 0:19:12There will come a moment
0:19:12 > 0:19:16when all of your neural activity will come to a halt
0:19:16 > 0:19:21and then the glorious experience of being conscious will come to an end,
0:19:21 > 0:19:25and it doesn't matter who you know or what you do,
0:19:25 > 0:19:27it's the fate of all of us.
0:19:27 > 0:19:29It's the fate of all life,
0:19:29 > 0:19:33but only humans are so unusually intelligent
0:19:33 > 0:19:35that we suffer over this.
0:19:37 > 0:19:41'When someone dies, those who are left grieve.
0:19:41 > 0:19:44'They mourn the lost relationship
0:19:44 > 0:19:48'but, with every death, there's another loss.
0:19:48 > 0:19:52'Every brain contains a lifetime of information,
0:19:52 > 0:19:55'experiences, knowledge, wisdom.
0:19:55 > 0:20:01'At the moment of death, all that becomes lost.'
0:20:01 > 0:20:06Francis Crick was one of the discoverers of the structure of DNA.
0:20:06 > 0:20:09And he was also a friend and a mentor to me.
0:20:09 > 0:20:11And when he died,
0:20:11 > 0:20:13I remembered thinking about what a waste it was
0:20:13 > 0:20:17that he was cremated and this brain of one of the greats
0:20:17 > 0:20:20of 20th-century biology was going up in flames.
0:20:20 > 0:20:25Because, even after a person dies, there's a lot of information
0:20:25 > 0:20:29about them stored in the physical structure of their brain.
0:20:29 > 0:20:31And we are reaching a point in neuroscience where it becomes
0:20:31 > 0:20:35a possibility that we could preserve a brain
0:20:35 > 0:20:39and read out the information and live with that person again.
0:20:42 > 0:20:45Brain preservation is a new field.
0:20:45 > 0:20:49It's controversial and its promise is still unproven.
0:20:50 > 0:20:54Nonetheless, some people are actively exploring the possibility.
0:20:58 > 0:21:00Here in the Arizona desert,
0:21:00 > 0:21:05the researchers at the Alcor Life Extension Foundation
0:21:05 > 0:21:08believe they can give the dead a chance to live again.
0:21:11 > 0:21:15This facility holds the remains of over 100 people
0:21:15 > 0:21:18preserved at ultra-low temperature.
0:21:21 > 0:21:25It's run by Max More, who describes himself as a futurologist.
0:21:28 > 0:21:31As soon as legal death has been declared, which is really not
0:21:31 > 0:21:33biological death, but we have to wait for that point legally,
0:21:33 > 0:21:36we can then move the patient from the bed into the ice bath,
0:21:36 > 0:21:40we can add external ice on top, we restart respiration...
0:21:40 > 0:21:43we restart circulation by doing essentially mechanical CPR
0:21:43 > 0:21:46and then we also administer 16 different medications to try
0:21:46 > 0:21:48and protect the cells as we cool down.
0:21:48 > 0:21:52Each body is submerged in liquid nitrogen,
0:21:52 > 0:21:55bringing its temperature below -300 degrees.
0:21:56 > 0:21:59This process is known as cryonic suspension
0:21:59 > 0:22:03and it doesn't require a whole body.
0:22:03 > 0:22:07Sometimes a client chooses to preserve only their head and brain.
0:22:07 > 0:22:10So what we will do is we'll do the neuro separation
0:22:10 > 0:22:12somewhere down here, a few vertebras down.
0:22:12 > 0:22:15We'll move the patient's cephalon into the cephalon ring
0:22:15 > 0:22:17where the head is essentially upside down
0:22:17 > 0:22:21so we can access the carotids and, just like the whole body procedure,
0:22:21 > 0:22:24except there we go through the chest, here we are washing out
0:22:24 > 0:22:26the blood and body fluids from the brain.
0:22:26 > 0:22:32The idea is to perfectly preserve a body into the distant future,
0:22:32 > 0:22:36with the hope that an advanced technology not yet invented
0:22:36 > 0:22:39will allow for thawing and reanimation.
0:22:39 > 0:22:43So, Max, tell me about these dewars.
0:22:43 > 0:22:45Well, our patients are stored in these.
0:22:45 > 0:22:49We call this a bigfoot dewar. It contains four whole body patients.
0:22:49 > 0:22:52So, as you can see from this 3-D printed model,
0:22:52 > 0:22:55each of those goes in an aluminium pod that gives extra protection
0:22:55 > 0:22:59and we also get five neuro patients in the centre column.
0:22:59 > 0:23:03So these fill up with about 450 gallons of liquid nitrogen.
0:23:03 > 0:23:07They're not sealed, we just have a polystyrene cap floating on the top
0:23:07 > 0:23:10and we top these up once a week with liquid nitrogen to keep them full.
0:23:10 > 0:23:13- So there are nine people in here? - Not in every one.
0:23:13 > 0:23:15It depends on how many neuro patients we have.
0:23:15 > 0:23:18There's actually room for more neuro patients.
0:23:18 > 0:23:21So some of them have neuro patients, others don't,
0:23:21 > 0:23:22so between four and nine.
0:23:22 > 0:23:25Alcor began 50 years ago.
0:23:25 > 0:23:30Currently, it houses 129 frozen residents...
0:23:30 > 0:23:33and that number continues to grow.
0:23:33 > 0:23:35Some of the pictures say,
0:23:35 > 0:23:39"First Life Cycle, 1927-1996."
0:23:39 > 0:23:42Do you see it as being a second life cycle?
0:23:42 > 0:23:44What we're doing is we're really just giving people
0:23:44 > 0:23:47another chance at life. Just as if today you're in your 30s or 40s,
0:23:47 > 0:23:50had a heart attack and we did some experimental surgery
0:23:50 > 0:23:53and brought you back, you might have several decades more.
0:23:53 > 0:23:55But we're talking something a little bit more radical.
0:23:55 > 0:23:57We're talking not just another 80 years,
0:23:57 > 0:24:00but potentially thousands of years, maybe longer.
0:24:00 > 0:24:04The people in these dewars have taken a leap of faith
0:24:04 > 0:24:06into an unknown future.
0:24:06 > 0:24:09There's no guarantee that the technology will ever
0:24:09 > 0:24:12come along that allows them to wake up again.
0:24:15 > 0:24:19So perhaps there are other ways to access the information
0:24:19 > 0:24:21stored in a brain -
0:24:21 > 0:24:25not by bringing a deceased person back to life,
0:24:25 > 0:24:28but by finding a way to read out the data directly.
0:24:29 > 0:24:34This is both a promising idea and a monumental challenge.
0:24:41 > 0:24:45At the Department of Brain and Cognitive Sciences at MIT,
0:24:45 > 0:24:50Sebastian Seung is among one of the first pioneers of that process.
0:24:50 > 0:24:53He's attempting to map out the innumerable connections that
0:24:53 > 0:24:56underlie a brain's function.
0:24:57 > 0:25:00That unimaginably vast network of pathways
0:25:00 > 0:25:03and links is called the connectome.
0:25:05 > 0:25:08Your connectome is unique.
0:25:08 > 0:25:11It's one of the deepest theories in neuroscience
0:25:11 > 0:25:15that your memories are stored in your unique pattern of connections.
0:25:17 > 0:25:20I like to think of it as a theory of personal identity -
0:25:20 > 0:25:22what makes you you.
0:25:24 > 0:25:28The average human brain has 86 billion neurons
0:25:28 > 0:25:33and thousands of trillions of synaptic connections.
0:25:33 > 0:25:36When the connectome is fully worked out,
0:25:36 > 0:25:40it will be the most complex wiring diagram ever created.
0:25:44 > 0:25:48It's very difficult to map out conductivity inside the brain.
0:25:48 > 0:25:52There's only one technology right now which promises to give us
0:25:52 > 0:25:55all the connections from a single piece of brain
0:25:55 > 0:25:58and that's called serial electron microscopy.
0:25:59 > 0:26:02Seung is beginning by mapping a mouse brain.
0:26:03 > 0:26:07The process starts with taking a piece of brain tissue
0:26:07 > 0:26:09and slicing it.
0:26:09 > 0:26:14It's a hi-tech deli slicer for cutting very thin slices of brain.
0:26:15 > 0:26:18To cut really thin, you have to have a very sharp knife.
0:26:18 > 0:26:21This is the world's sharpest knife, a diamond knife,
0:26:21 > 0:26:24whose blade is honed to atomic sharpness.
0:26:24 > 0:26:27You can see a metal part which is moving up and down,
0:26:27 > 0:26:29a piece of the brain is mounted on it
0:26:29 > 0:26:33and the brain is being moved back and forth against a blade.
0:26:34 > 0:26:39So slice after slice of brain are floating onto the surface
0:26:39 > 0:26:43of the water - each slice pushes the previous slice of forward.
0:26:43 > 0:26:45In order to see this cutting process,
0:26:45 > 0:26:50a microscope is mounted on top of the ultra-microtome and it projects
0:26:50 > 0:26:54an image onto this computer screen where we see the cutting happening.
0:26:54 > 0:26:59This conveyor belt produces a tape, a very long tape, which is
0:26:59 > 0:27:03kind of like a movie, every frame of which is a slice of brain.
0:27:06 > 0:27:10Once the brain has been arranged in these film-like strips,
0:27:10 > 0:27:13each sample is subdivided into tiny areas,
0:27:13 > 0:27:17which are then scanned by a powerful electron microscope.
0:27:18 > 0:27:21That process produces this,
0:27:21 > 0:27:26a segment of the brain magnified 100,000 times.
0:27:29 > 0:27:33At this resolution, it's possible to see almost every feature.
0:27:35 > 0:27:39These small black dots are DNA inside an individual cell.
0:27:44 > 0:27:47The next step is to compile these images.
0:27:48 > 0:27:52By stacking them in the thousands, one on top of each other,
0:27:52 > 0:27:56and then tracking the neurons through each image,
0:27:56 > 0:27:59it's possible to reconstruct the exact way that the neurons
0:27:59 > 0:28:04are connected, a three-dimensional model of the conductivity.
0:28:05 > 0:28:10It should be possible to do this with a whole human brain someday.
0:28:10 > 0:28:14The result would be a map of all the wiring that underpins
0:28:14 > 0:28:18a person's thoughts, experiences and beliefs.
0:28:20 > 0:28:21There's just one issue.
0:28:23 > 0:28:27If you image an entire human brain with this resolution,
0:28:27 > 0:28:30it would be a zettabyte of information.
0:28:31 > 0:28:34Sounds like a dirty word, a zettabyte.
0:28:34 > 0:28:36You've never heard it before, it's never spoken in polite company.
0:28:36 > 0:28:40Well, it's the total digital content of the world right now.
0:28:40 > 0:28:43That's...how much information it would be.
0:28:44 > 0:28:46It's a daunting figure.
0:28:47 > 0:28:51Does it mean that the idea of reading out a human brain
0:28:51 > 0:28:54will always remain beyond our reach?
0:28:54 > 0:28:58Well, experience says that computing power alone shouldn't be
0:28:58 > 0:29:00a barrier for too much longer.
0:29:04 > 0:29:08There is a common observation in computing called Moore's law.
0:29:09 > 0:29:13It states that processing power doubles every two years.
0:29:15 > 0:29:18If that doesn't sound like much, think of it this way.
0:29:18 > 0:29:23It means that computers today are one million times more powerful
0:29:23 > 0:29:24than they were in the 1970s.
0:29:30 > 0:29:34Just 20 years ago, this supercomputer behind me
0:29:34 > 0:29:37was equivalent to all the computing power on the planet.
0:29:39 > 0:29:4220 years from now, it will probably be considered a modest force
0:29:42 > 0:29:47of the type you might shrink down and wear on your body.
0:29:47 > 0:29:51We're in an era now where we are developing technologies that
0:29:51 > 0:29:57can store unimaginable amounts of data and run gargantuan simulations
0:29:57 > 0:30:02and this is where our biology is on a crash course with our technology.
0:30:04 > 0:30:09So let's say the time will come when computer power isn't an issue.
0:30:09 > 0:30:12That opens up a new realm of possibility.
0:30:13 > 0:30:18Suppose we could make a digital copy of the brain.
0:30:18 > 0:30:22Then, not only could we read it out, we could make it run.
0:30:23 > 0:30:26In the same way that computer software can run on different
0:30:26 > 0:30:30hardware, it may be that the software of the mind can
0:30:30 > 0:30:33run on other platforms.
0:30:33 > 0:30:36In other words, what if there's nothing special
0:30:36 > 0:30:39about the biological neurons themselves,
0:30:39 > 0:30:42and instead it's only how they connect and interact
0:30:42 > 0:30:44that makes a person who they are?
0:30:44 > 0:30:47If that proved to be correct, it would follow
0:30:47 > 0:30:53that we can exist digitally by running ourselves as a simulation.
0:30:53 > 0:30:56And this is what is known as the computational hypothesis
0:30:56 > 0:30:58of the brain.
0:30:58 > 0:31:01The idea is that the wet biological gushy stuff
0:31:01 > 0:31:03isn't the important part.
0:31:03 > 0:31:07What matters are the computations that are running on top.
0:31:07 > 0:31:11The idea is that the mind is not what the brain is,
0:31:11 > 0:31:13it's what the brain does.
0:31:14 > 0:31:20In theory, you might swap cells for circuits, oxygen for electricity.
0:31:20 > 0:31:23The medium doesn't matter, provided all the pieces
0:31:23 > 0:31:26and parts are connecting and interacting in the same way.
0:31:29 > 0:31:32All your thoughts, emotions, memories,
0:31:32 > 0:31:36your whole personality would still emerge.
0:31:36 > 0:31:38There'd be no biological brain,
0:31:38 > 0:31:42but there'd still be a fully functioning version of you.
0:31:44 > 0:31:46This sounds like science fiction,
0:31:46 > 0:31:50but a team in Switzerland has begun an exceptionally ambitious
0:31:50 > 0:31:53project that takes the first steps down this path.
0:31:55 > 0:32:01They're attempting to build a full working simulation of a brain.
0:32:01 > 0:32:03It's called the Blue Brain Project.
0:32:03 > 0:32:06Sean Hill is one of the members of the team.
0:32:08 > 0:32:10What is the long-term goal here?
0:32:10 > 0:32:15To deliver by 2023 a software and hardware infrastructure
0:32:15 > 0:32:20capable of running a whole human brain simulation.
0:32:20 > 0:32:24If we want to move towards being able to simulate an entire
0:32:24 > 0:32:27human brain, how do we know what are the important things to capture,
0:32:27 > 0:32:30the structure of the cells all the way down to the proteins,
0:32:30 > 0:32:31the molecules, how do we know?
0:32:31 > 0:32:34We're working at sub-cellular, we're working at cellular,
0:32:34 > 0:32:36we're working at micro circuit,
0:32:36 > 0:32:40we're working at brain regions, the meso circuits,
0:32:40 > 0:32:44and then we have whole brain but for very simplified neurons.
0:32:44 > 0:32:46So our goal is to get to whole brain
0:32:46 > 0:32:48but with the very detailed neurons.
0:32:48 > 0:32:51As a starting point, they're looking at rat brains.
0:32:51 > 0:32:55They take tiny slices of brain and subject them
0:32:55 > 0:32:58to minute jolts of electrical current.
0:32:58 > 0:33:00That mimics the activity of the living brain
0:33:00 > 0:33:04and prompts the cells to interact.
0:33:04 > 0:33:07Each interaction is recreated on the project's supercomputer
0:33:07 > 0:33:10and then integrated into a larger model with
0:33:10 > 0:33:14data from hundreds of other labs around the world.
0:33:14 > 0:33:17The result is this electrical storm.
0:33:20 > 0:33:24This is the best approximation of what a very tiny fraction
0:33:24 > 0:33:29of your brain is doing when you're, say, just staring into space.
0:33:30 > 0:33:34The total activity in your brain is hundreds of millions times
0:33:34 > 0:33:36more than what you're seeing here.
0:33:37 > 0:33:39And this typhoon of activity
0:33:39 > 0:33:43is roaring along every second of your life.
0:33:44 > 0:33:45We're not building abstract models.
0:33:45 > 0:33:48We're actually taking data from laboratories,
0:33:48 > 0:33:51we're extracting probabilities, we're extracting distributions
0:33:51 > 0:33:54from that to build a much larger model
0:33:54 > 0:33:56that is based on biological data.
0:33:56 > 0:33:58Not based on the assumption of how biology works,
0:33:58 > 0:34:02but actually on data that comes out of a bio laboratory.
0:34:05 > 0:34:09The Blue Brain Team hopes to achieve their goal by 2023 -
0:34:09 > 0:34:12a full working simulation of a human brain.
0:34:14 > 0:34:16And that raises a question.
0:34:16 > 0:34:18What will the finished product be?
0:34:18 > 0:34:22Will it be a mind? Will it think, will it be self-aware?
0:34:25 > 0:34:29If the answer is yes and a mind can live in a computer,
0:34:29 > 0:34:34then do we have to copy nature's biological blueprints
0:34:34 > 0:34:39or might it be possible to program a different kind of intelligence,
0:34:39 > 0:34:41one of our own invention?
0:34:49 > 0:34:53People have been trying for a long time to create machines that think.
0:34:53 > 0:34:56This field, called artificial intelligence, has been
0:34:56 > 0:34:58around since at least the 1950s.
0:35:00 > 0:35:04The problem has turned out to be unexpectedly difficult,
0:35:04 > 0:35:07and this speaks to the extraordinary enigma of
0:35:07 > 0:35:10how the brain does what it does.
0:35:13 > 0:35:16Because while we'll soon have cars that drive themselves
0:35:16 > 0:35:20and it's almost two decades since a computer first beat
0:35:20 > 0:35:23a chess grandmaster,
0:35:23 > 0:35:28the goal of a truly sentient machine still waits to be achieved.
0:35:32 > 0:35:36One of the latest attempts to create an artificial intelligence
0:35:36 > 0:35:39can be found at the University of Plymouth in England.
0:35:41 > 0:35:44It's called iCub.
0:35:44 > 0:35:49It's a humanoid robot and it's designed to learn as a child learns.
0:35:50 > 0:35:53Traditionally, robots are pre-programmed with everything
0:35:53 > 0:35:55they need to know.
0:35:55 > 0:35:59But what if you could create a robot by developing it
0:35:59 > 0:36:01the way a human infant grows?
0:36:01 > 0:36:04ICub is about the size of a two-year-old.
0:36:04 > 0:36:07It has eyes and ears and touch sensors
0:36:07 > 0:36:11and these allow it to interact with the world and learn from it.
0:36:12 > 0:36:16Babies don't come into the world knowing how to speak and walk,
0:36:16 > 0:36:21but they come with curiosity and they pay attention and they imitate.
0:36:21 > 0:36:24They use the world that they're in as a textbook
0:36:24 > 0:36:26so they can learn by example.
0:36:26 > 0:36:30So what if you wanted to create a robot to do the same thing?
0:36:30 > 0:36:34Well, you would take a crude brain simulation and you'd give it
0:36:34 > 0:36:38a mechanical body so that it could interact with the world.
0:36:41 > 0:36:44- Hello.- Hello, I'm iCub.
0:36:45 > 0:36:48This is a red ball.
0:36:48 > 0:36:50It's a red ball.
0:36:50 > 0:36:52This is a yellow cup.
0:36:52 > 0:36:53Yellow cup.
0:36:55 > 0:36:58The aim is that, with each interaction,
0:36:58 > 0:37:01the robot continually adds to its base of knowledge.
0:37:01 > 0:37:03It's making connections
0:37:03 > 0:37:07and building a repertoire of appropriate responses.
0:37:07 > 0:37:10And, because it looks and sounds a bit like a human,
0:37:10 > 0:37:14it's easy to be convinced that it thinks like one.
0:37:14 > 0:37:16Where is the yellow cup?
0:37:22 > 0:37:24Where is the red ball?
0:37:28 > 0:37:32Often, iCub gets it wrong - that's part of the process.
0:37:32 > 0:37:36- What is this?- I'm sorry, I don't know what this is.
0:37:39 > 0:37:41But the more it gets it wrong,
0:37:41 > 0:37:46the more you get the sense there's no real mind behind the program.
0:37:48 > 0:37:50What is this?
0:37:50 > 0:37:52I'm sorry, I don't know what this is.
0:37:54 > 0:37:58What becomes clear is that iCub is purely mechanical.
0:37:59 > 0:38:02You can feel that it's run by lines of code,
0:38:02 > 0:38:05instead of trains of thought.
0:38:05 > 0:38:07So, it can say "red ball",
0:38:07 > 0:38:13but does it really experience redness or the concept of roundness?
0:38:13 > 0:38:15Do computers do just what they're programmed to do,
0:38:15 > 0:38:21or can it ever really have internal experience?
0:38:24 > 0:38:28In the 1980s, the philosopher John Searle was chewing on this problem,
0:38:28 > 0:38:31and he came up with a thought experiment
0:38:31 > 0:38:35that gets right at the heart of it, and he called this the Chinese Room.
0:38:37 > 0:38:40'The experiment goes like this.
0:38:40 > 0:38:42'I am locked in a room.
0:38:42 > 0:38:46'Outside, there is someone who only communicates in Chinese.
0:38:47 > 0:38:50'She writes out some questions,
0:38:50 > 0:38:53'and then posts those to me in the room.'
0:38:53 > 0:38:56Now, I don't speak Chinese.
0:38:56 > 0:38:59But I do have these books. And they give me instructions
0:38:59 > 0:39:02on exactly what to do with these symbols.
0:39:02 > 0:39:07So, I look in the book and, if I can find a match to the symbols,
0:39:07 > 0:39:10then the book tells me exactly how to respond.
0:39:10 > 0:39:12So, I can look up this response.
0:39:15 > 0:39:17That matches, so, now,
0:39:17 > 0:39:21I can post this as the reply to the message I received.
0:39:22 > 0:39:25'When our Chinese speaker receives the message,
0:39:25 > 0:39:27'it makes perfect sense to her.
0:39:36 > 0:39:38'As far as she's concerned,
0:39:38 > 0:39:41'we're having a conversation in her language.'
0:39:42 > 0:39:44Just by following a set of instructions,
0:39:44 > 0:39:49I can convince somebody on the outside that I speak Chinese.
0:39:49 > 0:39:52And, if I have a large enough set of response books,
0:39:52 > 0:39:55I can have a conversation about anything.
0:39:55 > 0:39:57But, here's the important part.
0:39:57 > 0:40:02I, the operator, do not understand Chinese.
0:40:02 > 0:40:04I can manipulate symbols all day long.
0:40:04 > 0:40:08But none of it has any meaning to me.
0:40:08 > 0:40:14'The argument goes that this is just what happens inside a computer.
0:40:14 > 0:40:17'No matter how sentient it seems,
0:40:17 > 0:40:21'the computer is only ever following instructions.
0:40:21 > 0:40:24'Manipulating symbols.'
0:40:27 > 0:40:30Now, not everybody agrees with this interpretation of the Chinese Room.
0:40:30 > 0:40:32Some people point out that,
0:40:32 > 0:40:35although the operator doesn't understand Chinese,
0:40:35 > 0:40:39the system as a whole, the operator plus the books,
0:40:39 > 0:40:41does understand Chinese.
0:40:41 > 0:40:44Whatever the correct interpretation, the important thing is this.
0:40:44 > 0:40:48It exposes the difficulty and the mystery
0:40:48 > 0:40:53of how physical pieces and parts ever come to equal
0:40:53 > 0:40:57our experience of being alive in the world.
0:40:57 > 0:41:03With every attempt to simulate or create subjective experience,
0:41:03 > 0:41:07we are confronted with one of the greatest mysteries of neuroscience.
0:41:07 > 0:41:11Every brain cell is just a cell.
0:41:13 > 0:41:17Running its basic operations, following its local rules,
0:41:17 > 0:41:23how do billions of these add up to the feeling of me?
0:41:28 > 0:41:34'If we want to see how simple parts can give rise to something bigger,
0:41:34 > 0:41:38'one can look to the natural world.'
0:41:38 > 0:41:44The Houston Zoo is home to a large colony of leafcutter ants.
0:41:44 > 0:41:48Individually, each ant behaves simplistically.
0:41:48 > 0:41:53But, when these ants work together, the colony is like a super organism
0:41:53 > 0:41:56that accomplishes something much greater.
0:41:57 > 0:42:00All of these ants have a different job.
0:42:00 > 0:42:03There are some that are really, really good at just cutting leaves.
0:42:03 > 0:42:05Others that are good at carrying leaves.
0:42:05 > 0:42:07And then others that do other functions within the group.
0:42:07 > 0:42:12They're independent, but they all work towards a common cause.
0:42:12 > 0:42:17So, they are all coming out, doing what their job is to do,
0:42:17 > 0:42:20for the good of the whole colony.
0:42:20 > 0:42:22So, do these ants communicate by chemical signalling?
0:42:22 > 0:42:25Yes, they do. Whenever they find something that is
0:42:25 > 0:42:29a great leaf for them to cut, or fruit or vegetables,
0:42:29 > 0:42:33when one ant goes and finds that, they will relay that signal,
0:42:33 > 0:42:35and then the rest will just follow.
0:42:35 > 0:42:37It becomes a very straight line, instead of them branching out,
0:42:37 > 0:42:40going different directions, to get to the same thing.
0:42:40 > 0:42:42They all follow the chemical signal.
0:42:42 > 0:42:46So, what happens if one of these ants is just off by himself?
0:42:46 > 0:42:49If we were to get this guy, this is a bigger ant here.
0:42:49 > 0:42:52- Yeah, poor guy, he's just running... - Going around in circles.
0:42:52 > 0:42:54..and spinning in circles, yeah.
0:42:56 > 0:42:59He's not getting that signal, that chemical signal back
0:42:59 > 0:43:03that you are going in the right directions.
0:43:03 > 0:43:07This ant can't function outside the network of local signals
0:43:07 > 0:43:11because he needs those to tell him what to do.
0:43:11 > 0:43:13Put him back into the network
0:43:13 > 0:43:16and he does just what's needed to serve the greater purpose.
0:43:18 > 0:43:22The scout ants only worry about where to find the best plants.
0:43:22 > 0:43:26The leafcutters do the cutting.
0:43:26 > 0:43:29The carriers know which parts to bring back to the nest.
0:43:30 > 0:43:37And there, inside, other ants build, tend, harvest, mate.
0:43:37 > 0:43:42It's an entire system regulated by local signalling between them.
0:43:42 > 0:43:47In all of this, no one ant sees the big picture
0:43:47 > 0:43:50about the agricultural society they have created.
0:43:50 > 0:43:52And it doesn't matter.
0:43:52 > 0:43:55The power of the colony emerges
0:43:55 > 0:43:59from the local interactions between the ants.
0:43:59 > 0:44:02Put enough ants together and, bang, you get a super organism
0:44:02 > 0:44:06with sophisticated properties that don't belong to any of the parts.
0:44:06 > 0:44:10And this is the concept of emergent properties.
0:44:10 > 0:44:13Put enough simple units together,
0:44:13 > 0:44:18and have them interact in the right ways, and something larger emerges.
0:44:21 > 0:44:25The idea is that something like this happens in the brain.
0:44:25 > 0:44:27A neuron has certain properties.
0:44:27 > 0:44:30It can gather chemical and electrical signals,
0:44:30 > 0:44:33and spit out signals to other neurons.
0:44:33 > 0:44:36But, fundamentally, it's a cell,
0:44:36 > 0:44:39like trillions of others in the human body.
0:44:39 > 0:44:43It spends its life embedded in a network of other cells
0:44:43 > 0:44:49and, whatever its function, all it does is react to local signals.
0:44:49 > 0:44:51Just like the ant,
0:44:51 > 0:44:55a brain cell spends its life running its local programmes.
0:44:55 > 0:44:57But, get enough brain cells together,
0:44:57 > 0:45:02interacting in the right ways, and the mind emerges.
0:45:04 > 0:45:09The concept of emergent properties offers a possible way to understand
0:45:09 > 0:45:12how the vast neural populations of the brain
0:45:12 > 0:45:15might produce consciousness.
0:45:15 > 0:45:18And it gives rise to a question.
0:45:18 > 0:45:20Could consciousness emerge
0:45:20 > 0:45:24from anything that has lots of interacting parts?
0:45:24 > 0:45:26Could a city be conscious?
0:45:29 > 0:45:32Or maybe it's not enough to have lots of simple pieces interacting.
0:45:32 > 0:45:38Maybe the parts need to interact in very specific ways.
0:45:40 > 0:45:44If that's true, then we might expect to find particular signatures
0:45:44 > 0:45:48of activity in networks that are conscious.
0:45:52 > 0:45:55At the University Of Wisconsin,
0:45:55 > 0:45:58Giulio Tononi and his team are hunting for those signatures.
0:46:00 > 0:46:03They're focusing on the transition to consciousness
0:46:03 > 0:46:08that happens in the brain every single day when we wake up.
0:46:11 > 0:46:15When you wake up in the morning, from a dreamless sleep,
0:46:15 > 0:46:19before, there was absolutely nothing, and then you are awake
0:46:19 > 0:46:22and, in the space of a few seconds, there is everything.
0:46:24 > 0:46:29Colours, sounds, people, thoughts, desires, plans for the day.
0:46:29 > 0:46:32And, of course, the world around you.
0:46:33 > 0:46:35That is consciousness.
0:46:37 > 0:46:42Tononi's experiments use TMS, transcranial magnetic stimulation,
0:46:42 > 0:46:47to make small, targeted disruptions in brain activity.
0:46:48 > 0:46:52And they can do this while a person is awake, or asleep.
0:46:53 > 0:46:55In the awake brain,
0:46:55 > 0:46:58an electrical pulse moves outwards across the cortex,
0:46:58 > 0:47:00like ripples on a pond.
0:47:01 > 0:47:06But, in the sleeping brain, only nearby areas react.
0:47:06 > 0:47:08The ripples hardly spread.
0:47:11 > 0:47:14When you fall into a dreamless sleep,
0:47:14 > 0:47:18somehow, the neurons are not able to talk to each other.
0:47:18 > 0:47:21What we activate with TMS remains very local,
0:47:21 > 0:47:24it remains there, it doesn't travel any more.
0:47:24 > 0:47:28That spread of activity across the waking brain
0:47:28 > 0:47:30may be a clue to consciousness.
0:47:30 > 0:47:34While different regions of the brain are invested in different tasks,
0:47:34 > 0:47:38consciousness seems to have something to do with
0:47:38 > 0:47:42integrating activity across vast brain territories,
0:47:42 > 0:47:46linking areas to produce a single, unified experience.
0:47:48 > 0:47:51You don't have an experience split in two pieces.
0:47:51 > 0:47:53When I see your shirt,
0:47:53 > 0:47:56I don't see a shape and the colour separated from each other.
0:47:56 > 0:47:58They are together, they are bound together.
0:47:58 > 0:48:00So, every experience is one.
0:48:02 > 0:48:05'Every moment of experience is a composite
0:48:05 > 0:48:09'created from innumerable possibilities.
0:48:09 > 0:48:12'I might be feeling the heat of the day.
0:48:12 > 0:48:14'I might be remembering an event from high school.
0:48:14 > 0:48:20'My stomach might be digesting lunch. I'm also seeing, I'm hearing.
0:48:20 > 0:48:23'My brain will create my sense of self
0:48:23 > 0:48:26'from all these different strands.
0:48:26 > 0:48:29'How the strands are woven together is still a mystery.'
0:48:29 > 0:48:32But Tononi believes that the key to consciousness
0:48:32 > 0:48:36is contained in these patterns of interaction.
0:48:36 > 0:48:39He also believes that this key
0:48:39 > 0:48:43doesn't have to belong only to biological creatures.
0:48:43 > 0:48:45That definitely is how it evolved.
0:48:45 > 0:48:49And it takes an organisation of that kind to do it.
0:48:49 > 0:48:52It just needs to be made the right way.
0:49:00 > 0:49:03Building consciousness on another medium
0:49:03 > 0:49:06is still squarely in the realm of speculation.
0:49:08 > 0:49:11It could turn out that there is something special about neurons
0:49:11 > 0:49:16so that only a biological brain could produce consciousness.
0:49:17 > 0:49:23Nonetheless, this idea offers us a glimpse of one possible future.
0:49:25 > 0:49:27With powerful enough computers
0:49:27 > 0:49:30simulating all the interactions of a human brain,
0:49:30 > 0:49:34we could, one day, become non-biological beings.
0:49:34 > 0:49:38And that would be the greatest leap in the history of our species.
0:49:38 > 0:49:41We could leave these bodies behind.
0:49:44 > 0:49:48'Digitally, you could live whatever life you wanted,
0:49:48 > 0:49:52'wherever you wanted, with a kind of immortality on offer.'
0:49:53 > 0:49:56While the stars are far beyond the reach of
0:49:56 > 0:49:58any flesh-and-blood human lifespan,
0:49:58 > 0:50:05you could be uploaded, and sent off to experience other solar systems.
0:50:07 > 0:50:11Or, you could enter an existence in a simulated world.
0:50:13 > 0:50:15One in which you flew.
0:50:18 > 0:50:20Or lived underwater.
0:50:21 > 0:50:24Or lived a life of luxury.
0:50:26 > 0:50:31Maybe you could journey into a reconstructed version of the past.
0:50:34 > 0:50:39When we imagine simulated life, the choices are endless.
0:50:39 > 0:50:41'And they include a strange possibility
0:50:41 > 0:50:44'that what we're talking about
0:50:44 > 0:50:48'is something that's happening already, right now.'
0:50:48 > 0:50:51The simulation could look something like this.
0:50:51 > 0:50:54And it could be that we're already in it.
0:50:56 > 0:50:59'Now, that idea might seem preposterous.
0:51:00 > 0:51:03'But it's surprisingly difficult to disprove.'
0:51:05 > 0:51:08It seems hard to imagine that all of this could be a simulation.
0:51:08 > 0:51:12But we already know how easily we can be fooled.
0:51:12 > 0:51:15Every night when you go to sleep, you have bizarre dreams.
0:51:15 > 0:51:20And, when you're there, you believe those worlds entirely.
0:51:21 > 0:51:25The fact that you can be so fooled by your dreams
0:51:25 > 0:51:29is sufficient reason to question what you are experiencing right now.
0:51:31 > 0:51:34The philosopher Rene Descartes wondered,
0:51:34 > 0:51:39how can we ever know whether what we're experiencing is reality?
0:51:39 > 0:51:42He said, how do I know I'm not just a brain in a vat
0:51:42 > 0:51:47that's being stimulated in just the right ways so that I believe that
0:51:47 > 0:51:51I am touching the ground, and seeing people, and hearing their voices?
0:51:51 > 0:51:54And he realised there's no way to know.
0:51:54 > 0:51:58'But he realised something else, that there is some "me"
0:51:58 > 0:52:01'at the centre of all this, trying to figure this out.'
0:52:03 > 0:52:08So, even if I am a brain in a simulation, I am thinking about it.
0:52:08 > 0:52:11And, therefore, I am.
0:52:22 > 0:52:24Over the course of this series,
0:52:24 > 0:52:29we've discovered just how complex and remarkable the human brain is.
0:52:31 > 0:52:35How reality is something constructed inside our heads.
0:52:37 > 0:52:40How we are built to need others.
0:52:41 > 0:52:45How so much of who we are, and what we choose to do,
0:52:45 > 0:52:50is governed by factors outside our conscious minds.
0:52:54 > 0:52:58Now, it seems to me that we stand at a major turning point,
0:52:58 > 0:53:02one where we might take control of our own development.
0:53:04 > 0:53:08We face a future of unchartered possibilities...
0:53:09 > 0:53:12..in which our relationship with our own body,
0:53:12 > 0:53:16our relationship with the world,
0:53:16 > 0:53:20the very basic nature of who we are,
0:53:20 > 0:53:23is set to be transformed.
0:53:24 > 0:53:26For thousands of generations,
0:53:26 > 0:53:30humans have lived the same life cycle over and over.
0:53:30 > 0:53:33We're born, we control a fragile body,
0:53:33 > 0:53:38we experience a limited reality, and we die.
0:53:38 > 0:53:41But science and technology are giving us tools
0:53:41 > 0:53:44to transcend that evolutionary story.
0:53:44 > 0:53:48Our brains don't have to remain as we've inherited them.
0:53:48 > 0:53:54We're capable of extending our reality, of inhabiting new bodies,
0:53:54 > 0:53:58and possibly shedding our physical forms altogether.
0:53:58 > 0:54:01Our species is just at the beginning of something,
0:54:01 > 0:54:05and we're discovering the tools to shape our own destiny.
0:54:05 > 0:54:08Who we become is up to us.