‐(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.
♪ ♪
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.
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