All language subtitles for The Brain with Dr. David Eagleman - 01x06 - Who Will We Be.HDTVx264-DHD.English.updated.Addic7ed.com

Over the last 100,000 years,

our species has been
on quite a ride.

We've gone from primitive
hunter-gatherers

poking around for scraps

to a world-conquering,
city-dwelling,

hyperconnected super species,

and it's all thanks
to the 3 pounds

of wet biological material
stored up here.

We live surrounded
by our inventions.

We have the means to travel,

to make,

to communicate,

to build.

What I find incredible
is that all of this

was built with the same
neural material

that our ancestors used to hunt
and to build primitive tools.

The genius of mother nature
and the secret to her success

was to build a brain that could
innovate to make the journey

from primitive man to this
in a very short amount of time.

I want to explore what it is
about the brain

that's made
this journey possible.

If we can understand
how it works,

then maybe we can
direct its power in new ways

and open a new chapter
in the human story.

So what's next for our brains?

What do the next 1,000 years
have in store for us,

and in the far future,

what is the human race
going to look like?

What will we be capable of?

This is a journey
into who we might become.

We'll look at how we can
use our brains

to control new kinds
of bodies...

How our sensory experience
can be expanded to new horizons.

We'll look at how
we might one day

separate our minds
from our physical selves,

even possibly overcome death.

The human body...

It's a masterpiece
of complexity and beauty.

It's a symphony
of 40 trillion cells,

all operating in concert,

and it's all orchestrated

by the 3-pound organ
we call the brain.

Sensory information floods in.

Decisions are made.

Responses are formulated.

The brain sends out commands,

and the body moves into action,

but what if the brain
could do more, handle more?

What if there were other ways
for it to operate?

We're heading for
a fundamental change

in the relationship
between the body, the brain,

and the outside world.

We're marrying our biology
with our technology,

and that's poised to transform
who we will be.

This is all possible,
thanks to a special property

of the brain called plasticity.

It's best illustrated
through a remarkable story.

Meet Cameron mott.

In this home movie,
she's 4 years old.

♪ I'm a Princess girl all day ♪

♪ a Princess girl, prin... ♪

I'm a Princess girl.

Eagleman, voice-over:
One day, Cameron

suddenly started
having seizures.

Oh! Ooh...

Woman, voice-over:
The really big issue was that

Cameron's seizures were
drop seizures where she would

fall down to the floor
very quickly,

and they were very aggressive.

Cameron?
Oh!

Whoopsy.

Eagleman, voice-over:
She was diagnosed

with rasmussen's syndrome,

an inflammatory disease
that attacks the brain.

It causes paralysis
and, ultimately, death.

To save Cameron's life,

her physicians proposed
a radical solution.

They would remove
the diseased part of her brain.

Little harder.

Man, voice-over: The procedure
itself is probably

the most drastic
surgical procedure

that can be done
in neurosurgery.

You know, it's not
a simple operation.

There are man...

On a scale of 1 to 10,

10 being one of the more
difficult operations

that we would typically perform
in neurosurgery,

I'd say it's a 10.

Eagleman, voice-over:
Seeing no other option,

Cameron's parents consented.

The real risk
in the surgery is not

what happens
if we do the surgery.

The question is,
what happens to this person

if we don't do the surgery?

Eagleman, voice-over: The issue
was that an entire half

of Cameron's brain
had been affected.

Woman, voice-over: Our biggest
concern was, would she survive?

Would there be
some complication?

Um, would we go
through all of this

and then still have seizures
at the end?

This is Cameron's
preoperative scan.

This is the material
that underpins her intellect

and her emotion
and her sense of humor,

who she is.

In this scan, the empty space

is where half of her brain
has been removed.

No one could be sure
how the loss

of that much brain tissue
would affect Cameron.

What would she lose?

Could she be
like other children?

This is Cameron 7 years on.

She's seizure-free...

And, more importantly,

beyond a slight weakness
on one side,

she betrays no sign
of the ordeal

that she went through.

I like to run a lot

and do different types
of stuff outside.

I love math.

Give me... give me 3 quizzes
to do, and I'll do it.

Ok. Let it go.

Just imagine taking your laptop
and tearing out

half the motherboard and
expecting it still to function.

It would never
work with a computer,

but it can work
with a young brain...

And that has
dramatic implications.

We used to think of the brain
as a fixed system

with different parts dedicated
to specific jobs,

like seeing or deciding
or moving,

but no region
works in isolation.

The brain is a vast, dynamic,
interconnected network

that's always changing.

Instead of hardwired,
I like to think of the brain

as live-wired, and
that flexibility of the brain

opens up new possibilities
for our future.

It could be argued that
this future has been with us

since the 1970s in the form
of a simple piece of technology.

This is a cochlear implant,

and it can give hearing
to deaf people.

It picks up sounds and converts
them to electrical signals

that plug directly
into the cells of the inner ear.

Now, when it was
first introduced,

researchers didn't think
it was going to work

because biology is wired up
with such precision

and specificity
and this just takes

crude signals and shoves them
into the brain

in a way that the brain's
not expecting.

The cochlear implant
represents a marriage

between metal electrodes
and biological cells,

and yet it works.

Around the world, almost
a quarter-million people

have had the chance to hear
for the first time,

thanks to these implants.

Wow. Ha ha ha!

Eagleman, voice-over:
Here's how.

Whether it comes from your ears
or your eyes

or a touch on your skin,
all the information

that enters your brain is
converted into the same stuff...

Electrochemical signals.

These are the common currency
of the brain.

When the implant produces
these signals, however crudely,

the brain finds a way
to make sense of them.

It hunts for patterns...

Cross-referencing
with other senses.

At first, the signals
are unintelligible,

but soon, meaning emerges.

Cochlear implants reveal
something amazing

about the brain, which is,
whatever signals you feed

into it,
the brain will figure out

how to extract
something useful out of that.

As long as the data coming in
has a structure

that maps onto
the outside world,

the brain will figure out
how to decode it,

and this turns out to be one
of nature's greatest tricks,

and now that we know about it,

it opens up a world
of possibilities.

Why restrict ourselves
to trying to replace

lost or damaged senses?

There must be ways
for us to enhance

or add to the senses
that we already have.

In my laboratory,
we've created this vest.

It turns sound
into patterns of vibration

that are felt on the skin
of the torso.

The idea is that,
given enough time,

the wearer's brain will learn

to automatically decode
these vibrations.

They'll instinctively feel
and understand information.

This is the alien language game,

so you're gonna feel
a word presented to you

as a pattern of vibration
on your torso.

Through time,
you're going to get

better and better
at this as your brain

starts decoding how these
inputs maps onto words

that you know, and your job

is just to figure out
what the language

of the vest is.

I can feel the
vibrations on my body.

It makes no sense to me.
They're just random.

I'm aware that maybe one
in the left shoulder,

right shoulder, lower back...

Eagleman, voice-over:
One of my lab members, Joshua,

wore the vest
as he went about his day.

An app sends a pattern
of vibrations to his torso.

He guesses what word
that pattern represents,

and he's told
whether he's right or wrong.

Joshua, voice-over:
For the first week or so,

I mean, it's just total nonsense

to try to figure out which word
was just projected onto me,

but as time has gone by,
I am able to,

through some process,
distinguish them.

Eagleman, voice-over:
It seems strange that you could

understand information
through your torso,

but that's the surprise.

It doesn't matter how signals
find their way to the brain.

We have these peripheral senses
that we plug in,

but here's the thing.

Our eyes, our nose, our mouth...

These are just what we inherit
from our evolutionary past.

It's what we come
to the table with,

but we don't
have to stick with it

because it might be possible
that we could plug

some sensory channel into
an unusual port into the brain

and the brain
will just figure it out,

and it may be that
in the near future,

we can invent new sorts
of sensory devices

and plug them directly
into the brain.

In theory, there's no limit

to the new sensory expansion
that we can create.

So just imagine if we could
feed in an input

of real-time weather data
so you could feel

if it's raining 100 miles away

or if it's gonna
snow tomorrow...

Or imagine feeding in
real-time stock data

and developing
an intuitive sense

of how the markets were moving.

You'd be plugged
into the global economy.

Because of the brain's capacity
to take on new inputs,

we should be able to expand
the experience of being human.

We could enjoy things
that wouldn't be possible

with the traditional senses
we arrive with.

It may be that the evolution
of our technology,

rather than our biology,

is what guides the journey
of our species from here on out.

As we move into the future,

we'll increasingly design
our own portals on the world.

As far as we can tell,

there's no limit in what
the brain can incorporate.

Instead, we now have
the tools to shape

our own sensory experiences,

to widen our small windows
on reality.

Eagleman, voice-over:
Now, how we sense the world,

that's only half the story.

The other half
is how we interact with it.

What if we could use
the brain's flexibility

to change our physical bodies?

This is jan scheuermann.

Because of a rare
genetic disease,

the spinal cord nerves
that connect her brain

to her muscles
have deteriorated.

Scheuermann, voice-over: I can't
move anything below my neck.

Where the stem of my brain
meets my spinal cord,

there's some
deterioration there,

and the signals
aren't getting through,

so my brain is saying,
"lift up," to my arm,

and my arm's saying,
"I can't hear you."

Eagleman, voice-over:
Now jan's participating

in a trailblazing experiment...

Part neurosurgery,
part robotics.

Two electrode arrays
implanted into her brain

provide a link from
her motor cortex to this...

The world's most advanced
robotic arm.

Ok. Up, down.

Eagleman, voice-over:
Its fingers can curl and uncurl.

It can roll. The wrist can flex.

Jan can control it
just by thinking about it.

Right...

And grasp.

Eagleman, voice-over: Though she
speaks the commands out loud,

she has no need to.

There's a direct physical link
between the arm and her brain.

Down.

Eagleman, voice-over:
An arm normally moves

because of a storm of activity
in the motor cortex.

From there, the signals
travel down the spinal cord

to the muscles of the arm.

In jan's case,
electrodes eavesdrop

on the cortical signals directly

and redirect those to Hector,
her new arm.

Scheuermann, voice-over:
Like riding a bicycle,

the brain doesn't forget
how to move the arm,

even though it hasn't moved
in... in 10 years.

Eagleman, voice-over:
With practice, this relationship

will become fully unconscious.

She'll be able to move Hector
automatically

without thinking about it,

just as we do
with our biological limbs.

Oh, it feels very
good to be able to shake hands

and fist-bump and interact.

It's so very life-affirming
to me to be able

to reach out and touch a person.

Eagleman, voice-over: Jan's
experience points to a future

in which we use technology to
enhance and extend our bodies,

not only replacing
limbs or organs,

but improving them,
elevating them

from human fragility
to indestructibility.

Hollywood has often imagined
a person who's part machine.

Well, that fantasy
is fast becoming real.

As we learn how to take on
new sensory experiences

and control new kinds of bodies,
that's going

to profoundly change
who we are as individuals,

and that's because
our physicality sets the tone

for how we feel and how we think
and who we are.

At this moment in history,
it may be that we have

more in common
with our stone-age ancestors

than we do with our descendants
in the near future.

We're already beginning
to extend the human body,

but no matter how much
we enhance ourselves,

there's something
we need to keep in mind.

Our body is made
of flesh and bones.

It's going to
deteriorate and die,

but what if the study
of the brain

could address our mortality?

What if in the future,
we didn't have to die?

There will come a moment
when all of your neural activity

will come to a halt, and then
the glorious experience

of being conscious
will come to an end,

and it doesn't matter
who you know or what you do.

It's the fate of all of us.

It's the fate of all life,
but only humans

are so unusually intelligent

that we suffer over this.

When someone dies,

those who are left grieve.

They mourn
the lost relationship,

but with every death,
there's another loss.

Every brain contains
a lifetime of information,

experiences, knowledge, wisdom.

At the moment of death,
all that becomes lost.

Francis crick
was one of the discoverers

of the structure of DNA,
and he was also a friend

and a mentor to me,
and when he died,

I remembered thinking
about what a waste it was

that he was cremated and
this brain of one of the greats

of 20th-century biology
was going up in flames

because even
after a person dies,

there's a lot of information
about them stored

in the physical structure
of their brain,

and we're reaching a point
in neuroscience

where it becomes a possibility
that we could preserve a brain

and read out the information
and live with that person again.

Brain preservation
is a new field.

It's controversial, and
its promise is still unproven.

Nonetheless, some people

are actively exploring
the possibility.

Here in the Arizona desert,
the researchers

at the alcor life extension
foundation believe

they can give the dead
a chance to live again.

This facility holds the remains
of over 100 people

preserved
at ultralow temperature.

It's run by Max more,

who describes himself
as a futurologist.

As soon as legal death
has been declared...

Which is really not
biological death,

but we have to wait
for that point legally...

We can then move the patient

from the bed into the ice bath.

We can add external ice on top.

We restart respiration.

We restart circulation by doing,
essentially, mechanical cpr,

and then we also administer
16 different medications

to try and protect
the cells as we cool down.

Eagleman, voice-over: Each body
is submerged in liquid nitrogen,

bringing its temperature
below minus-300 degrees.

This process is known
as cryonic suspension,

and it doesn't require
a whole body.

Sometimes a client
chooses to preserve

only their head and brain.

So what we'll do is,
we'll do the neuroseparation

somewhere down here,
a few vertebras down.

We'll move the
patient's cephalon

into the cephalon ring,
where the head

is essentially upside down
so we can excess the carotids,

and... just like with
the whole-body procedure,

except there, we go
through the chest...

Here, we're
washing out the blood

and body fluids
uh, from the brain.

Eagleman, voice-over: The idea
is to perfectly preserve a body

into the distant future

with the hope
that an advanced technology

not yet invented will allow
for thawing and reanimation.

So, Max, tell me
about these dewars.

All our patients
are stored in these.

We call this a bigfoot dewar.

Uh, it contains
4 whole-body patient,

as you can see from
this 3D-printed model.

Each of those goes
in aluminum pod

that gives extra protection,

and we also get 5 neuropatients

in the center column,

so these fill up
with about 450 gallons

of liquid nitrogen.

Uh, they're not sealed.

We just have a cap

floating on the top,
and we top these up

once a week with liquid nitrogen

to keep them full.

So there are 9 people in here?

Not in every one.

Depends on how many
neuropatients we have.

Uh, there's actually room
for more neuropatients,

so some of them
have neuropatients.

Others don't,
so between 4 and 9.

Eagleman, voice-over:
Alcor began 50 years ago.

Currently it houses
129 frozen residents,

and that number
continues to grow.

Some of the pictures say,

"first life cycle...
1927 to 1996."

Do you see it as being
a second life cycle?

What we're doing is,
we're really just

giving people another
chance at life.

Just as if today you were,
you know, in your 30s

or 40s, had a heart attack
and we did some

experimental surgery
and brought you back,

you might have
several decades more,

but we're talking something
a little bit more radical.

We're talking about not
just for another 80 years,

but potentially thousands
of years, maybe longer.

Eagleman, voice-over:
The people in these dewars

have taken a leap of faith
into an unknown future.

There's no guarantee that the
technology will ever come along

that allows them
to wake up again...

So perhaps there are other ways

to access the information
stored in a brain

not by bringing a deceased
person back to life,

but by finding a way to read out
the data directly.

This is both a promising idea
and a monumental challenge.

At the department of brain
and cognitive sciences at mit,

Sebastian seung is among the
first pioneers of that process.

He's attempting to map out
the innumerable connections

that underlie
a brain's function.

That unimaginably vast network
of pathways and links

is called the connectome.

Your connectome is unique.

It's one of the deepest theories
in neuroscience

that your memories are stored

in your unique pattern
of connections.

I like to think of it as
a theory of personal identity,

what makes you you.

Eagleman, voice-over:
The average human brain

has 86 billion neurons

and thousands of trillions
of synaptic connections.

When the connectome
is fully worked out,

it will be the most complex
wiring diagram ever created.

It's very difficult

to map out connectivity
inside the brain.

There's only one technology
right now which promises

to give us all the connections
from a single piece of brain,

and that's called
serial electron microscopy.

Eagleman, voice-over:
Seung is beginning

by mapping a mouse brain.

The process starts with taking
a piece of brain tissue

and slicing it.

It's a high-tech
deli slicer

for cutting very thin
slices of brain.

To cut really thin,

you have to have
a very sharp knife.

This is the world's
sharpest knife,

a diamond knife whose blade
is honed to atomic sharpness.

You can see a metal part
which is moving up and down.

A piece of brain
is mounted on it,

and the brain is being moved
back and forth against a blade,

so slice after slice of brain

are floating onto
the surface of water.

Each slice pushes
the previous slice forward.

In order to see
this cutting process,

a microscope is mounted
on top of the ultramicrotome,

and it projects an image
onto this computer screen,

where we see
the cutting happening.

This conveyor belt
produces a tape,

a very long tape
which is kind of like a movie,

every frame of which
is a slice of brain.

Eagleman, voice-over:
Once the brain has been arranged

in these filmlike strips,
each sample is subdivided

into tiny areas
which are then scanned

by a powerful
electron microscope.

That process produces this...

A segment of brain
magnified 100,000 times.

At this resolution,

it's possible to see
almost every feature.

These small, black dots are DNA
inside an individual cell.

The next step is to compile
these images.

By stacking them
in the thousands,

one on top of each other,

and then tracking the neurons
through each image,

it's possible to reconstruct
the exact way

that the neurons are connected,

a 3-dimensional model
of the connectivity.

It should be possible to do this
with whole human brain someday.

The result would be
a map of all the wiring

that underpins
a person's thoughts,

experiences, and beliefs.

There's just one issue.

If you image
an entire human brain

with this resolution,

it would be a zettabyte
of information.

Sounds like a dirty word,
"zettabyte."

You never heard it before.

It's never spoken
in polite company.

Well, it's the...

It's the total digital content
of the world right now.

That's, uh, how much
information it would be.

Eagleman, voice-over:
It's a daunting figure.

Does it mean that the idea
of reading out a human brain

will always remain
beyond our reach?

Well, experience says
that computing power alone

shouldn't be a barrier
for too much longer.

There's a common observation
in computing called Moore's law.

It states that processing power
doubles every two years.

If that doesn't sound like much,
think of it this way.

It means that computers today
are a million times

more powerful than they were
in the 1970s.

Just 20 years ago,
this supercomputer behind me

was equivalent to all the
computing power on the planet.

20 years from now,
it'll probably be considered

a modest force of the type

you might shrink down
and wear on your body.

We're in an era now where we're
developing technologies

that can store unimaginable
amounts of data

and run gargantuan simulations,
and this is where our biology

is on a crash course
with our technology.

So let's say the time will come

when computer power
isn't an issue.

That opens up a new realm
of possibility.

Suppose we could make
a digital copy of the brain.

Then not only we could
read it out.

We could make it run.

In the same way that
computer software can run

on different hardware, it may be
that the software of the mind

can run on other platforms.

In other words, what if
there's nothing special

about the biological neurons
themselves

and instead, it's only
how they connect and interact

that makes a person
who they are.

If that proved to be correct,
it would follow

that we can exist digitally
by running ourselves

as a simulation,
and this is what's known

as the computational hypothesis
of the brain.

The idea is that the wet,
biological, gushy stuff

isn't the important part.

What matters
are the computations

that are running on top.

The idea is that the mind
is not what the brain is.

It's what the brain does.

In theory, you might swap
cells for circuits,

oxygen for electricity.

The medium doesn't matter,
provided all the pieces

and parts are connecting
and interacting in the same way.

All your thoughts,
emotions, memories,

your whole personality
would still emerge.

There'd be no biological brain,

but there'd still be a fully
functioning version of you.

This sounds
like science fiction,

but a team in Switzerland
has begun

an exceptionally
ambitious project

that takes the first steps
down this path.

They're attempting to build

a full working simulation
of a brain.

It's called
the blue brain project.

Sean hill is one of the members
of the team.

What is
the long-term goal here?

To deliver by 2023
a software and hardware

infrastructure
capable of running

a whole human brain simulation.

If we want to move
towards being able

to simulate an entire
human brain,

how do we know what are

the important things
to capture...

The structure, the cells,
all the way down

to the proteins, the molecules?

How do we know?

We're working at subcellular.

We're working at cellular.

We're working at microcircuit.

We're working at brain regions

of mesocircuits,

and then we have whole brain

but for very simplified neurons,

so our goal is to
get to whole brain

but with very detailed neurons.

Eagleman, voice-over:
As a starting point,

they're looking at rat brains.

They take tiny slices of brain
and subject them

to minute jolts
of electrical current.

That mimics the activity
of the living brain

and prompts the cells
to interact.

Each interaction is recreated
on the project's supercomputer

and then integrated
into a larger model with data

from hundreds of other labs
around the world.

The result is
this electrical storm.

This is the best approximation

of what a very tiny fraction
of your brain is doing

when you're, say,
just staring into space.

The total activity in your brain
is hundreds of millions of times

more than what
you're seeing here,

and this typhoon of activity
is roaring along

every second of your life.

We're not building
abstract models.

We actually taking data
from laboratories.

We're extracting,
uh, probabilities.

We're extracting
distributions from that

to build a much larger
model that is based

on biological data,

not based on the assumption

of how... how biology
works, but actually

on data that comes out
of a biolaboratory.

Eagleman, voice-over:
The blue brain team hopes

to achieve their goal by 2023...

A full working simulation
of a human brain,

and that raises a question...

What will
the finished product be?

Will it be a mind?
Will it think?

Will it be
self-aware?

If the answer is yes and
a mind can live in a computer,

then do we have to copy
nature's biological blueprints,

or might it be possible
to program a different kind

of intelligence,
one of our own invention?

People have been trying
for a long time

to create machines that think.

This field, called
artificial intelligence,

has been around since
at least the 1950s.

The problem has turned out to be
unexpectedly difficult,

and this speaks
to the extraordinary enigma

of how the brain
does what it does...

Because, while we'll soon have
cars that drive themselves

and it's almost two decades
since a computer

first beat a chess grand master,

the goal of a truly
sentient machine

still waits to be achieved.

One of the latest
attempts to create

an artificial intelligence
can be found

at the university of Plymouth
in england.

It's called icub.

It's a humanoid robot,

and it's designed to learn
as a child learns.

Traditionally,
robots are preprogrammed

with everything
they need to know,

but what if you could
create a robot

by developing it the way
that a human infant grows?

Icub is about the size
of a two-year-old.

It has eyes and ears
and touch sensors,

and these allow it to interact
with the world

and learn from it.

Babies don't come into the world
knowing how to speak and walk,

but they come with curiosity,

and they pay attention,
and they imitate.

They use the world
that they're in as a textbook

so they can learn by example,

so what if you wanted to create
a robot to do the same thing?

Well, you would take
a crude brain simulation,

and you'd give it
a mechanical body

so that it could
interact with the world.

Hello.

Hello.
I'm icub.

This is a red ball.

This is a red ball.

This is a yellow cup.

Yellow cup.

Eagleman, voice-over: The aim
is that with each interaction,

the robot continually adds
to its base of knowledge.

It's making connections

and building a repertoire
of appropriate responses,

and, because it looks and sounds
a bit like a human,

it's easy to be convinced
that it thinks like one.

Where is the yellow cup?

Where is the red ball?

Eagleman, voice-over:
Often, icub gets it wrong.

That's part of the process...

What is this?

I'm sorry. I don't
know what this is.

Eagleman, voice-over:
But the more it gets it wrong,

the more you get the sense

there's no real mind
behind the program.

What is this?

I'm sorry. I don't
know what this is.

Eagleman, voice-over:
What becomes clear

is that icub
is purely mechanical.

You can feel that it's run
by lines of code

instead of trains of thought,

so it can say, "red ball,"

but does it really
experience redness

or the concept of roundness?

Do computers do just what
they're programmed to do,

or can it ever really have
internal experience?

In the 1980s,
the philosopher John searle

was chewing on this problem,
and he came up

with a thought experiment that
gets right at the heart of it,

and he called this
the Chinese room.

Eagleman, voice-over:
The experiment goes like this.

I'm locked in a room.

Outside, there's someone who
only communicates in Chinese.

She writes out some questions

and then posts those
to me in the room.

Now, I don't speak Chinese,
but I do have these books,

and they give me instructions
on exactly what to do

with these symbols,
so I look in the book,

and... and if I can find
a match to the symbols,

then the book tells me
exactly how to respond,

so I can look up this response.

That matches,
so now I can post this

as the reply
to the message I received.

Eagleman, voice-over:
When our Chinese speaker

receives the message,
it makes perfect sense to her.

Eagleman, voice-over:
As far as she's concerned,

we're having a conversation
in her language.

Just by following
a set of instructions,

I can convince somebody
on the outside

that I speak Chinese,

and if I have a large enough set
of response books,

I can have a conversation
about anything,

but here's the important part.

I, the operator,
do not understand Chinese.

I can manipulate symbols
all day long,

but none of it
has any meaning to me.

The argument goes that this

is just what happens
inside a computer.

No matter how sentient it seems,

the computer is only ever
following instructions,

manipulating symbols.

Now, not everybody agrees
with this interpretation

of the Chinese room.

Some people point out
that, although the operator

doesn't understand Chinese,
the system as a whole,

the operator plus the books,
does understand Chinese.

Whatever the correct
interpretation,

the important thing is this.

It exposes the difficulty
and the mystery

of how physical pieces and parts

ever come to equal

our experience of being alive
in the world.

With every attempt to simulate
or create subjective experience,

we're confronted with
one of the greatest mysteries

of neuroscience.

Every brain cell
is just a cell...

Running its basic operations,
following its local rules.

How do billions of these add up
to the feeling of me?

If we want to see
how simple parts

can give rise
to something bigger,

one can look
to the natural world.

The Houston zoo is home

to a large colony
of leaf cutter ants.

Individually, each ant
behaves simplistically,

but when these ants
work together,

the colony is like
a super organism

that accomplishes
something much greater.

All of these ants
have a different job.

There are some that
are really, really good

at just cutting leaves,

others that are good
at carrying leaves,

and then others that
do other functions

within the group.

They're independent,
but they all work

towards a common cause,

so they're all coming out doing

what their job is
to do for the good

of the whole colony.

So do these ants communicate
by chemical signaling?

Yes. They do.

Whenever they find
something that is,

you know, a great
leaf for them to cut

or fruit or vegetables,

uh, when one ant
goes and finds that,

they will lay that signal,

and then the rest
will just follow it,

and it becomes a
very straight line.

Instead of them branching out,

going different directions

to get to the same thing,

they all follow the...
The chemical signal.

So what happens
if one of these ants

is just off by himself?

So if we were to get this guy,

this is a bigger ant here.

Yeah. Poor guy. He's just...
He's just running...

Going around in circles.

Spinning in circles.
Yeah.

He's not getting that signal,

that chemical signal, back

that, "you are going in
the right directions."

Eagleman, voice-over:
This ant can't function

outside the network
of local signals

because he needs those
to tell him what do.

Put him back into the network,

and he does just what's needed
to serve the greater purpose.

The scout ants only worry about
where to find the best plants.

The leaf cutters do the cutting.

The carriers know which parts
to bring back to the nest,

and there, inside, other ants
build, tend, harvest, mate.

It's an entire system

regulated by local signaling
between them.

In all of this,
no one ant sees the big picture

about the agricultural society
they've created,

and it doesn't matter.

The power of the colony emerges

from the local interactions
between the ants.

Put enough ants together,
and, bang,

you get a superorganism
with sophisticated properties

that don't belong
to any of the parts,

and this is the concept
of emergent properties.

Put enough simple units together
and have them interact

in the right ways,
and something larger emerges.

The idea is that something
like this happens in the brain.

A neuron has certain properties.

It can gather chemical
and electrical signals

and spit out signals
to other neurons,

but fundamentally, it's a cell,

like trillions of others
in the human body.

It spends its life embedded
in a network of other cells,

and, whatever its function,

all it does is react
to local signals.

Just like the ant,
a brain cell spends its life

running its local programs,

but get enough brain cells
together

interacting in the right ways,
and the mind emerges.

The concept of emergent
properties offers a possible way

to understand how the vast
neural populations of the brain

might produce consciousness, and
it gives rise to a question...

Could consciousness
emerge from anything

that has lots
of interacting parts?

Could a city be conscious?

Or maybe it's not enough

to have lot of simple pieces
interacting.

Maybe the parts need to interact
in very specific ways.

If that's true,
then we might expect to find

particular signatures
of activity

in networks that are conscious.

At the university of Wisconsin,
giulio tononi and his team

are hunting
for those signatures.

They're focusing on
the transition to consciousness

that happens in the brain every
single day when we wake up.

Tononi, voice-over:
When you wake up in the morning

from a dreamless sleep,

before, there was
absolutely nothing,

and then you're awake,

and in the... the space
of a few seconds,

there is everything...

Colors, sounds, people,
thoughts, desires,

plans for the day, and,
of course, the world around you.

That is consciousness.

Eagleman, voice-over:
Tononi's experiments use tms,

transcranial
magnetic stimulation,

to make small, targeted
disruptions in brain activity,

and they can do this while
a person is awake or asleep.

In the awake brain,
an electrical pulse

moves outwards across the cortex
like ripples on a pond,

but in the sleeping brain,
only nearby areas react.

The ripples hardly spread.

Tononi, voice-over: When you
fall into dreamless sleep,

somehow the neurons are not able
to talk to each other.

What we activate with tms
remains very local.

It remains there.
It doesn't travel anymore.

Eagleman, voice-over:
That spread of activity

across the waking brain
may be a clue to consciousness.

While different regions
of the brain are invested

in different tasks,
consciousness seems to have

something to do with
integrating activity

across vast brain territories,

linking areas to produce
a single, unified experience.

Tononi, voice-over:
You don't have an experience

split in two pieces.

When I see your shirt,

I don't see a shape and the
color separated from each other.

They are together.

They are bound together,
so every experience is one.

Eagleman, voice-over:
Every moment of experience

is a composite created
from innumerable possibilities.

I might be feeling
the heat of the day.

I might be remembering an event
from high school.

My stomach might be
digesting lunch.

I'm also seeing. I'm hearing.

My brain will create
my sense of self

from all these
different strands.

How the strands are woven
together is still a mystery,

but tononi believes that
the key to consciousness

is contained in these patterns
of interaction.

He also believes that this key

doesn't have to belong only
to biological creatures.

That definitely
is how it evolved,

and it takes an organization
of that kind to do it.

It just needs to be made
the right way.

Eagleman, voice-over: Building
consciousness on another medium

is still squarely
in the realm of speculation.

It could turn out that there's
something special about neurons

so that only a biological brain
could produce consciousness.

Nonetheless, this idea
offers us a glimpse

of one possible future.

With powerful enough computers
simulating all the interactions

of a human brain,
we could one day become

nonbiological beings,
and that would be

the greatest leap
in the history of our species.

We could leave
these bodies behind.

Digitally, you could live
whatever life you wanted

wherever you wanted with a kind
of immortality on offer.

While the stars
are far beyond the reach

of any flesh-and-blood
human lifespan,

you could be uploaded
and sent off

to experience
other solar systems...

Or you could enter an existence
in a simulated world...

One in which you flew...

Or lived underwater

or lived a life of luxury.

Maybe you could journey
into a reconstructed version

of the past.

When we imagine simulated life,
the choices are endless,

and they include
a strange possibility

that what we're talking about
is something

that's happening already
right now.

The simulation could look
something like this,

and it could be
that we're already in it.

Now, that idea
might seem preposterous,

but it's surprisingly difficult
to disprove.

It seems hard to imagine
that all of this

could be a simulation,
but we already know

how easily we can be fooled.

Every night
when you go to sleep,

you have bizarre dreams,
and when you're there,

you believe those worlds
entirely.

The fact that you can be
so fooled by your dreams

is sufficient reason to question

what you're experiencing
right now.

The philosopher Rene descartes
wondered, "how can we ever know

whether what we're experiencing
is reality?"

He said, "how do I know
I'm not just a brain in a vat

"that's being stimulated
in just the right ways

"so that I believe
that I'm touching the ground

and seeing people
and hearing their voices?"

And he realized
there's no way to know,

but he realized something else,
that there's some me

at the center of all this
trying to figure this out,

so even if I am a brain
in a simulation,

I'm thinking about it,

and, therefore, I am.

Over the course of this series,

we've discovered
just how complex

and remarkable
the human brain is,

how reality is something
constructed inside our heads,

how we're built
to need others...

How so much of who we are
and what we chose to do

is governed by factors
outside our conscious minds.

Now it seems to me that we stand
at a major turning point,

one where we might take control
of our own development.

We face a future
of uncharted possibilities

in which our relationship
with our own body,

our relationship with the world,

the very basic nature
of who we are

is set to be transformed.

For thousands of generations,

humans have lived the same
life cycle over and over.

We're born.
We control a fragile body.

We experience a limited reality,
and we die,

but science and technology
are giving us tools

to transcend
that evolutionary story.

Our brains don't have to remain
as we've inherited them.

We're capable of extending
our reality,

of inhabiting new bodies,

and possibly shedding
our physical forms altogether.

Our species is just
at the beginning of something,

and we're discovering the tools
to shape our own destiny.

Who we become is up to us.

"The brain with David eagleman"

"the brain with David eagleman"

is available on DVD.

The companion book is

also available.

To order, visit
shoppbs. Org

or call
1-800-play-pbs.