Original subtitles

-(clicking tongue) -with his ears.

A deaf man who hears

with his eyes.

And a man who lives in a world

completely devoid of pain.

Sight, sound,

taste, touch and smell.

These five senses are what we humans use

to perceive the world around us.

We tend to think we understand them pretty well.

After all, we use them every day.

But what about people whose abilities

are so acutely developed,

they challenge everything we know about our minds,

our bodies, and even reality itself.

Well, that is what we'll try and find out.

THE UNXPLAINED - SEASON 2 EP - 10 - Superhuman Senses

Professional swordsman Isao Machii

is about to perform an incredible demonstration.

He will attempt to cut a baseball,

traveling at a hundred miles per hour,

perfectly in half,

and from a distance of only 30 feet away.

It seems impossible.

That is...

until he does it.

MICHAEL DENNIN: When I first saw

the video of the samurai cutting the ball in half,

I was absolutely amazed.

What I like about video these days

is you can do some simple physics.

You know, he's maybe sort of 30 feet away,

the ball is roughly a hundred miles an hour,

and that gives you a reaction time

of essentially .2 seconds, in this case.

Typical reaction times for a really elite baseball player

trying to hit a fastball tend to be around .4 seconds.

Actually, this is a more difficult task

than something like baseball pitching, because clearly,

with baseball pitching, you pick up information

from the body shape of the pitcher,

which tells you loosely

when the ball is going to be released.

Whereas in this instance,

he seems to have a wall in front of him.

There's a lot of uncertainty

in terms of when the ball will begin its flight.

And the fact that he can do all these things

in 200 milliseconds is obviously quite amazing.

SHATNER: In this

and in numerous other demonstrations,

Machii has shown a remarkable ability

to visually track fast-moving objects

with an acuity that few can even dream of.

But how?

Perhaps the answer can be found by examining the history

of a man who can "see" the world around him

just as well as, or even better,

than most people,

despite the fact that he doesn't have eyes.

Two-year-old Daniel Kish,

just one year after having both eyes removed due to cancer,

sneaks out of his crib

to explore his family's backyard.

Far from being fearful or afraid,

Daniel is as confident as he is curious,

because, at just two years old,

he has developed an ability called echolocation,

which allows him to see by using his ears.

For those of us that study sensory systems,

Daniel Kish is a rock star.

(clicking tongue)

He is clearly the most studied human

that actively echolocates.

(indistinct chatter in distance)

So he will emit sounds himself.

These sounds will go and bounce off objects

and come back to his own ears,

and these noises provide him information on...

distance to a target, what that target might actually be,

how dense it is, how light it might be,

its shape.

I've been able to echolocate for as long as I can remember,

and for me it was as natural as breathing.

It was just my way of seeing.

I didn't really know it was echolocation per se.

I just knew that I was aware of my surroundings

and that I could function with that awareness.

It was just sort of part of the process of learning to see,

which is very much what sighted kids actually do

as they begin to calibrate their vision.

After that, it was just sort of normal.

It was just a matter of course to click and scan

and find things

and to not really be afraid of what was out there.

LOMBER: For most of us,

if you've ever had any experience with echolocation,

it's probably when you've been told

about how bats work, right?

Bats emit a sound.

The sound bounces off objects and then comes back to them.

So they can actually determine how far away an object is,

what its size and shape may be, and so forth.

And what Daniel's done is, he's taken this idea

and, uh, basically, uh, turned it into something

that humans can actually use.

KISH: Without ultrasonic hearing,

without all of the advantages that bats have evolved,

humans are somehow able to do this,

and relatively easily.

So... how? Why?

I believe that we can do this because we always have.

We've been doing it since man was prey and not predator,

since we had to hide in the dark.

So we don't have to develop these systems from scratch.

All we have to do is turn them on.

(clicking tongue)

SHATNER: By making clicking sounds

and then listening to how those sounds reverberate

off what's around him,

Daniel is able to create a virtual picture

of his surroundings with astonishing accuracy.

(tongue clicking)

ANIL SETH: Neurobiologically,

I think this speaks to something

that we call sensory substitution.

That his visual cortex has been appropriated, if you like,

because it's not receiving visual information.

SHATNER: Daniel's rare abilities

made him the world's foremost echolocator.

But there are some in the scientific community

who question the extraordinary nature of Daniel's ability.

They argue that it's more likely

that Daniel's simply making lucky guesses

when he claims to sense his environment.

But for Daniel, there's no question.

He sees a map in his mind.

And what's more...

-(clicking tongue) -he can prove it.

LOMBER: Even though he's never seen,

he's clearly using his echolocation skills

to construct some sort of map of the visual world,

although he doesn't have any experience

with the visual world the way someone that's sighted does.

(clicking tongue)

KISH: When I visit a new place,

I basically just look around.

And for me, that involves, of course,

using my sense of echolocation

to scope out the environment.

I start out with what's most distinctive,

what stands out, uh, what's most unique,

uh, what seems to define the space.

Essentially, it resolves into what I call three-dimensional,

fuzzy geometry.

So all of these features

sort of coalesce into an actual image.

Mapping it is part of the process.

Drawing is a way of sharing

what my relationship with the environment is.

It's a way of...

giving people a peek into my head.

So, you've got a house here.

That's the most relevant feature.

There's a parked vehicle of some kind there.

And, then, trees.

And then, just as I got to about here,

I was able immediately to tell,

okay, this has got to be some sort of a patio area,

or maybe a grotto.

And then, as I rounded the area,

this tree line became very obvious,

that bounds one edge of the garden.

Daniel often says that, you know,

he can see these things in his mind,

and skeptics would say, "Oh, that's impossible,

"he must be hearing sounds or just making calculations

and guesses that just happen to be true."

But he's actually able to prove it.

He's actually able to draw what he sees in his mind.

And it's accurate.

KISH: I am a person who is naturally curious.

I've been an explorer since I got out of my crib

and started wandering around.

It didn't really occur to me that, "Oh, but wait,

I no longer have eyes."

My interest is in understanding the world,

knowing about the world,

and sharing whatever it is

I think I've learned about the world with others,

to the extent that others may benefit from that.

It's not about seeing or not seeing.

It's about knowing.

It's about understanding, and it's about sharing.

SHATNER: Daniel's incredible ability

to make his way through the world

is truly a sight to behold.

But how did he develop such an unusual

and powerful sensory ability?

Perhaps a clue can be found

by examining a group of people

who can literally hear the world around them

in color.

RICHARD CYTOWIC: We sense the world

where color has a sound,

and where sound has a taste.

If that all seems bizarre,

well, then imagine what it must be like

to live in that world

every day of your life.

? ?

Tofino, British Columbia, August 1998.

55-year-old Carol Steen and her husband

are hiking along the shores of the Pacific.

It's a day like any other.

That is, until Carol takes one wrong step.

There were all these black boulders, they were huge,

and we were kind of crawling around on them.

My husband, being athletic,

decided that he would jump off this rock.

I did the same thing.

And I did something very bad to my knee.

I ruptured the ACL.

SHATNER: Tearing an ACL is a traumatic injury,

even for professional athletes.

And yet, for Carol, the first thing she experienced

wasn't a sensation of pain

but one of color.

(woman breathing heavily)

STEEN: I didn't feel pain.

Instead, everything that I saw was orange,

and this was with my eyes open.

The sand was a lighter shade of orange.

The ocean was another shade of orange,

and the blur of orange was my husband,

and he said, "I'll get you up on some rocks,

and I'll go get help."

SHATNER: It may seem odd,

but this is just one example of Carol's senses mixing

that she has dealt with for years.

And it's an extraordinarily rare condition

that scientists refer to as synesthesia.

Synesthesia is often described

as an unusual union of the senses.

Perceptions that we tend to have separate--

like sounds versus sights versus touches versus smells--

get sort of combined in ways that are unusual.

They've identified at least 70 different forms

of synesthesia.

The common forms would be people

who can hear color and see sound.

There are two ways that we can perceive these joined senses.

90% of us see it in our mind's eye,

and that's the same place where you watch your daydreams.

And ten percent of us

see it actually projected out there in front of us.

(laughter)

SHATNER: Hearing color?

-Seeing sound? -(violins playing lively tune)

What a marvelously strange ability.

And yet, it's something that almost all of us do,

although to a much lesser extent.

CYTOWIC: We're all synesthetes.

There are cross-connections

going on in all of us, except

we're not consciously aware of them.

And so, what makes synesthetes different is

that they simply have more cross-connections

than you or I do,

and they are also consciously aware

that they have them.

SHATNER: In extreme cases of synesthesia,

a person, like Mississippi native

Lidell Simpson, for example,

can be born deaf and yet

somehow still be able to hear sounds.

(pinging slowly and rhythmically)

(pinging)

(clacking, whirring)

(sound of glass shattering)

Lidell is hearing the same way that you and I do.

It's just that his auditory cortex

is being stimulated not through the eardrum

but through other senses.

(pinging and whooshing)

It's like, well, suppose a blind person said to you,

"Oh, you poor thing. Everywhere you look,

"you're always seeing things.

Doesn't it drive you crazy having to see everything?"

And of course not, because

seeing is the normal texture of our reality.

Synesthetes simply have a different texture of reality

and different point of view.

Lidell is a fantastic example of brain plasticity.

I mean, when you think about an individual that's deaf

and has this large region of the brain

that's no longer processing sound,

the fact that these other modalities

have basically set up camp

in what would normally be his auditory cortex

is really phenomenal.

In most instances of synesthesia,

there's some mixing of the senses,

but it doesn't necessarily involve all the senses.

For Lidell, he seems

to conjure this rich, very complex auditory scene

out of all the things that he encounters.

When we think about people with synesthesia,

um, I think one of the reasons

why people with normal sensory systems find them so interesting

is because they're clearly having experiences

that we'll never have.

And trying to understand how they're experiencing the world

through somebody else's eyes and ears

is always really interesting to think about.

Synesthesia shows that we sense the world

in a much more integrated way than we think we do.

SHATNER: Synesthesia reminds us

of the brain's extraordinary ability

to process data in a most unconventional way.

Such is the case of one man

whose sensory condition sounds like a dream

but can, at times,

be a nightmare.

JOHN WOOD: Pain38-year-old Steven Peteharm:

attends to his Sunday chores, like yard work

and cooking and tinkering

with several projects in his basement.

All the same things that any person might do on a weekend.

But for Steven, he has to do all this far more carefully

than the average person, because for him,

doing household chores is more than just a series of tasks.

It's actually dangerous.

PETE: I was born

with a rare genetic condition called congenital analgesia.

At the time, that was the name given to it.

Now it's called congenital insensitivity to pain.

So, uh, I can't feel any pain at all.

SHATNER: A life free of pain?

Sounds like something many of us would pay dearly for.

But for people like Steven,

death or severe injury lurks

around every corner.

PETE: My parents first noticed

something was different when I was teething

and I chewed off half my tongue.

That definitely alarmed them to, uh, something serious going on,

so they took me to my pediatrician,

who, uh, did a couple of tests and determined

that, more than likely, I didn't feel pain.

They ran needles up and down my spine,

uh, poked my feet a couple places.

I still didn't elicit a negative response, a painful response.

SHATNER: Steven's gruesome injury provides a stark reminder

that while most people probably don't think of pain as a sense,

it may actually be

the important sense of all.

WOOD: Congenital analgesia is

an inherited form of insensitivity to pain.

"Congenital" means it runs in the family,

and "analgesia" means that you don't feel pain.

You have no feeling of pain whatsoever.

It's some form of mutation in a gene

that's essential for pain perception.

When people first hear that I don't feel pain,

they think it is the greatest thing in the whole world.

They're like, "Wow, you got a superpower."

But my childhood was spending good chunks of time

in the hospital.

I'd stay anywhere between, like, four months

to maybe a year and a half, which isn't normal.

WOOD: It's an extremely problematic condition.

Pain protects us from self-harm,

and it's often the first sign of disease.

So people who are pain-free often die very young.

DENNIN: It's actually rather amazing

that he's made it

through life as far as he has.

I mean, the classic example

we would always hear about is learning

not to touch things that are hot.

Pain alerts us when we're doing something in the external world

that doesn't make sense and we should stop.

PETE: The one thing that I really have to keep an eye on

is probably whenever I'm engaged

in, like, a physical activity that's a little bit strenuous,

like doing yard work.

It's stuff like that, where I could injure myself

and not immediately realize it,

that could cause serious repercussions down the road.

DENNIN: When we think about senses,

we always think about the classic five senses:

sight, touch,

smell, taste and hearing.

One thing that's really interesting, though,

is, we basically have another sense,

which is our pain, our sense of pain.

We often just reject that as, well, that's just touch.

But that negates or doesn't think

about the internal pains we often feel,

whether it's headaches or stomachaches

or sore muscles, which really isn't quite touch.

Pain is another sense.

It's a sense that we call nociception.

It's conveyed by specific kinds of nerves

that get activated when, for instance,

we might touch a hot stove or cut ourselves.

WOOD: What's interesting is,

the brain can regulate pain dramatically,

but the basic drive that causes pain

is from the peripheral nerves.

The nerves that send information into the brain

don't work in congenital analgesia patients.

This loss of pain is caused by malfunctions

in a very small number of genes that are extremely rare.

One of them is involved in signaling

in the peripheral nerves.

It's called Nav1.7.

It's a protein that's called a sodium channel.

It's like an electrical switch.

And if that protein doesn't function properly,

then you can become pain-free.

SHATNER: Since Steven doesn't feel pain,

it begs the question:

what does he feel instead?

PETE: It's difficult for me to try to explain, but even though

I don't feel physical pain, what I can feel is

heat, cold,

touch, just like every other person.

What I do feel is probably a byproduct of pain,

is, like, these impulses, almost like a nerve firing.

Since 2012,

I have had the opportunity to be able to participate

in a couple studies with different universities.

I spent a good portion of my childhood in the hospital,

and during those stays

it was usually with people who felt pain,

and seeing people,

especially that young, who are going

through such painful experiences,

um, that's really what prompted me to sign up

for a lot of these studies when I was approached.

And the overall goal in a lot of these studies is

to try to create a nonnarcotic painkiller,

because the opioid crisis that our country is facing

is one that other nations are facing as well.

So I've been asked quite a lot,

with all these studies I've been participating in,

if I had the chance to feel pain,

if they could figure out what activates

or deactivates that switch,

would I myself want to feel pain?

Um, and my answer is just no.

Um, and that's only because I've damaged my body so much

throughout my entire life that,

if I were to feel pain right now,

I'd just be in a constant state of pain all the time.

Not only do I have a bad knee,

uh, but my back is a little bit messed up,

so my quality of life

would just be low,

and there's no way I could live like that.

Pain.

As devastating as it can be, it is clearly one of the senses

we shouldn't be so eager to live without.

But if our sense of pain can be diminished,

might it be possible for our other senses

to be enhanced?

Perhaps the answer can be found

by examining the story of a young man

whose musical abilities could be said to rival those

of a Beethoven.

ADAM OCKELFORD: He was only five years old, and already

is in the middle of a lesson,

when a blind five-year-old boy bursts through the door

and changes Adam's life forever.

I first met Derek 35 years ago.

And this totally blind little boy

was desperate to get at the piano.

And he just pushed us out of the way and got playing.

And I thought,

"God, he's mad."

You know, there were notes flying everywhere.

But he was playing "Don't Cry for Me, Argentina,"

but with lots of scales and arpeggios and chords.

And I suddenly thought, wow,

you know, he's not mad, he's a genius.

When I first tried to teach Derek,

it turned out he could just play any tune that I named.

He was only five years old, and already in his head

he clearly had thousands of songs already memorized.

Derek was born very premature,

and he had to have a lot of oxygen to keep him alive.

And we know from modern neuroscience

that doing that to a brain causes it to grow

in a slightly different way,

to wire itself up in a different way.

The thing with teaching autistic children like Derek

is to form a relationship with them.

He's got to trust you.

He's almost got to love you, really, as a little boy.

It's almost like a parent-child relationship.

(playing mid-tempo song)

So he'll trust you to take him into new territories

that he doesn't necessarily feel comfortable with.

It's got to be a human relationship.

? ?

TERRY WOGAN: He's making it up as he went along. That's terrific.

(applause)

Brilliant!

What a great gift and what a, what a great talent,

and it's something for you to be very proud of.

Derek Paravicini.

(applause)

SHATNER: Over the next 35 years,

Adam worked closely with Derek to hone his natural abilities.

The result...

Derek is not only a world- renowned professional pianist

but someone whom scientists believe

may be among a rare group of humans

who possess the most finely developed sense of hearing

in the world.

Ah!

(music ends)

-Well done, Derek. -Yay. Thank you.

OCKELFORD: The whole of Derek's musical ability

is really founded on one thing,

which is that his hearing is so acute,

he can hear tiny differences in notes

that most people can't.

And Derek can remember them as well.

Derek, shall we play our copy game?

We'll play our copy game, please, Adam.

Perfect pitch is really rare amongst people as a whole.

Probably about one in 10,000 people have perfect pitch.

But Derek has kind of perfect pitch-plus.

Play this note, exactly as it is. Ready?

-(strikes note) -(strikes same note)

So I can play one note, say F-sharp,

and Derek instantly hears it.

You know exactly which one it is, don't you?

-I do. -What if I play two notes?

But there's more to it than that,

'cause if he hears two notes,

or three notes, even ten notes,

-all at the same time... -Four notes.

Instantly, Derek can hear it.

Uh, seven notes.

In fact, we've done tests with him,

and he can hear ten notes.

And he processes them in less than half a second.

Yeah.

(Ockelford playing note clusters and Derek imitating them)

Every day I sit down and we start to play, and I think,

"How did you do that?" And that, to me,

is what keeps it interesting, because

musicians give me a window into the brain that's unique.

We have developed tools and research

to try to infer about what happens in someone's brain.

But I have personally been involved

in measuring Derek's ability,

and I can very confidently say

that I have exhausted our technological means

to actually try to develop

a test that could measure Derek's ability.

Some people say that Derek's abilities

are almost superhuman, but I would say

that it's much more sophisticated than that.

(playing "When the Saints Go Marching In")

Not only can he unpack tens,

dozens, hundreds of pitches;

he can make musical sense of them,

and that's something that only Derek can do.

I have not come across any piece of technology that can do that.

SHATNER: While Derek has set a new bar

for hearing aptitude,

it appears that his heightened sense

is not without its downsides.

Because, as superhuman as Derek's hearing is,

the rest of his mind seems to have paid a price.

-Yay! -Well done, Derek!

-You enjoy that? -Yay. Enjoyed that, Adam!

-Yay! Good session? -Good session.

The thing with Derek's abilities, they come at a cost.

They come at a cost of understanding language,

of being able to sustain himself independently,

being able to function independently.

Derek is almost like Alice in the looking glass.

Everything is reversed.

So really complicated things

that most people would find impossible,

like a whole piece of music,

go straight into his long-term memory.

Really easy things, like "what did you have for lunch today,"

just don't stick.

And that's the extraordinary enigma of Derek.

SHATNER: But what is it

that gives Derek his extraordinary ability?

Is it simply his means of compensating for his blindness?

Or is there something more to it than that?

DENNIN: When we think about these cases,

an obvious place to go is, oh, he's blind,

so it's the lack of eyesight that is contributing to this.

What I don't know, and I think people are still looking at is,

is that something that happens

sort of early on in the formation of the brain

that's purely a function of, oh,

the eyesight isn't really being connected?

Or is it a process that happens more over time?

Understanding what that connection is, I think,

is a very deep and interesting question.

LOMBER: I think, when you consider individuals that have

a severely impaired sense, like blindness or deafness,

they're gonna have a very different reality

than people that have more or less intact senses.

But don't think of it in terms just of the loss,

but the fact that they're gonna have amplifications

in their remaining intact senses.

OCKELFORD: The great thing about Derek

is Derek the person.

He's so much more than a clever musician.

Derek is above all a people person.

So he makes his music for people.

He'll remember people he meets

in terms of the pieces they like.

(playing lively tune)

He may not remember the name,

but he'll remember a particular piece of music

they asked for, even ten or 20 years later.

(song ends)

(applause, cheering, whooping)

Derek's gifts, while remarkable, remind us

that enhanced abilities of all kinds

often come at a cost.

But is that always the case, or is it possible

for us to unlock an unlimited number of sensory abilities

that we have within us?

Even those we don't even know we have?

CARSHATNER: RY: Scientist Cornelia Fermuller

publishes a study about how optical illusions

expose a fundamental flaw in our brain.

Even when we know our senses are being tricked,

like when we look at an optical illusion,

we are powerless to do anything about it.

And the truth is, our eyes are deceiving us all the time.

SETH: For me it's not so surprising

that it's easy to fool our brains with optical illusions.

Our brains are not designed to reflect reality as it is.

They're designed to make the best use

of these ambiguous sensory signals.

HOFFMAN: We all have an experiential reality.

We'll see a three-dimensional world

with objects and colors and shapes,

we'll hear sounds,

we'll taste things,

we'll feel things,

and that's our experiential reality.

Now, most of us tend to think

that our experiential reality is giving us a pretty clean map

of what the objective reality is.

But the probability that we have been shaped by evolution

to have our experiential reality match any aspect

of the objective reality is precisely zero.

Instead, what evolution has done

is given us a bunch of hacks so that you can survive.

We're not tuned to the truth.

We have simple tricks and hacks.

Put your blindfolds on for me, please.

SHATNER: A group of scientists have gathered to perform

an intriguing experiment designed to find out

whether children have sensory abilities beyond those

we already know.

These particular children

seem to be able to do something that is unimaginable.

Somehow, they can both read and identify objects

while wearing a blindfold.

Teacup.

CORY: We came across a group of children

who were able to read completely blindfolded.

Of course, in the beginning,

we said, "This is a trick. It's impossible."

The visual system works with light.

But when we were working with these children, you could

literally give them a book that they have never read before,

and they would put the blindfolds on,

and eventually they could see.

"Our day out is ruined.

"No mouse would put a paw out

in what-- that weather."

CORY: Somebody from the outside

looking in would say,

"What's going on here? This is impossible."

But if that's possible, then

what other abilities might we have

that we're not even aware of yet?

Tell me what I'm holding in my hand.

A wooden spoon.

So, we wanted to investigate this phenomenon.

In 2018,

we started to work with this Russian group.

We worked with a couple of scientists,

and they introduced a device inside the mask,

uh, that measured the number of light photons inside the mask.

Once the device showed that there was no light

whatsoever inside the mask,

then we started the test.

We also measured the brain waves of the subject.

And we could see that the person could see.

They could read as if they were seeing normally

without any mask or anything whatsoever.

Forty-two.

This is extraordinary.

How do you even begin to explain that?

SHATNER: How indeed?

Because these subjects seemingly were able to sense things

without using any of their five senses.

So, then what explains it?

Of course, everyone recognizes the five senses

that we all have.

However, it seems

that we are also able to have another sense,

another way to receive information,

retrieve data from the physical world

beyond the five senses that we all know of.

If you take a look at the animal kingdom,

they have six, seven senses as well.

Bees, for example,

can see ultraviolet radiation.

Birds are famous for being able to lock onto magnetism.

So if animals have other senses, then why can't we?

It all sounds a bit too ooga-booga, doesn't it?

Well, not according to a study published by scientists

from Caltech in 2019,

which suggests that humans can not only detect energy fields;

they can also sense the magnetic field of the Earth.

TRAVIS TAYLOR: The human brain has a lot of phenomena

going on inside it that uses electromagnetic charges

and electric fields.

And if you change the magnetic field around your brain,

it will impact what's going on inside your brain.

So, small magnetic fields are most certainly detectable.

We just may not realize we're detecting them.

WOOD: It wouldn't surprise me in any way

if there aren't aspects of, uh, brain function

that we are completely unaware of at the moment,

that we'll become aware of later

when we understand more about how the brain actually works.

SHATNER: Since it's already been proven

that humans have more than five senses,

could there really be something to the notion

that we have the potential to sense the world around us

in what some would consider bizarre or even mystical ways?

According to some researchers, the answer is yes.

And as evidence they point

to an incredible phenomenon known as paroptic vision.

LUTYENS: Paroptic vision was first proposed

by a surrealist writer called Rene Daumal,

who, as a teenager, practiced

seeing color through his fingertips.

So he'd put different colored handkerchiefs inside a box

and then he'd run tests to see

if he could tell what color the handkerchief was.

That sounds quite fringe, but I've done some experiments.

It's a rare ability, but I did find one person

who was able to detect the colors

through the fingertips.

I can't explain it, but she could detect color

with 80% reliability through her fingertips.

It's been discovered

that the skin has opsins embedded in them.

And opsins help the body calibrate

to circadian rhythms, to 24-hour rhythms.

So it's not too much of a stretch to think how opsins

could not just detect light but they could also detect color.

WOOD: Many people believe

that there are mysterious ways of sensing things

that don't involve the traditional senses.

And I believe that there's a perfectly reasonable expectation

that that may perhaps be true.

We don't really understand how the brain works at all.

SHATNER: As incredible as it is

to discover new senses, it's also a little unsettling.

Because if our brain is just using our senses

to constantly try and guess what reality is,

then how are we to know when it guesses wrong instead of right?

SETH: I like to think of perception

as a kind of controlled hallucination, because

there's no light in the skull, there's no sound in the skull.

All you've got to go on as a brain

are these noisy and ambiguous sensory signals.

Signals don't come with labels--

"I'm from a coffee cup" or "I'm from a cat."

And this is why, for instance, if you look up at the sky,

and there's some fluffy clouds, sometimes you might see faces.

CYTOWIC: Reality is not quite as real as people think.

We are often told that something looks red

because it reflects more red wavelengths.

But there's no such thing as red wavelengths.

Color is not a property of objects.

It's a property of brains.

It's simply the wonder that our brain is creating all of this

and that we can agree on so much.

Perception is about representing the world

and the body and the self

in the way that's most useful for the organism.

So if you see a color, that's not right or wrong.

Color is where the brain meets the universe

in a way that's useful for us.

I think we can all agree reality exists.

We think, therefore something exists.

But what it is

and how we will know what it is, is fun to explore.

Whether it's seeing the world without eyes,

hearing things no other humans can,

or unconsciously using senses we didn't even know we had,

humans possess incredible sensory abilities

that make us wonder--

what else might be out there that we have yet to detect?

It's a tantalizing question.

One that will, for now, remain unexplained.

Subtitles Diego Moraes(oakislandtk) www.opensubtitles.org

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