(bright music)
(bright upbeat music)
- Hi everyone, Jade here.
I've recently had an existential crisis
that made me question my entire life and existence,
since then, I've wanted to understand
the nature of true reality, and share my discoveries
with you guys so we can find out together.
So in this video, we're going to be taking
a closer look at reality.
While I was thinking about the best place to start,
it occurred to me, are humans even capable
of understanding reality, do we have the right tools,
do we see external reality as it truly is,
or a fictional story our senses tell us?
In the 18th century the great German philosopher
Immanuel Kant argued that we can never have access
to the unfiltered thing-in-itself of objective reality.
Plato compared our entire life experience
to mere shadows on a cave wall.
Now, a lot of time has passed since Kant and Plato
and a lot of advancements have been made in science,
we'll be exploring this question
through the lens of modern science.
And quick spoiler alert,
the conclusion is rather unsettling,
it turns out modern science actually agrees
with those old timey philosophers,
we don't see reality as it really is like at all.
(bell chimes) (bright music)
We generally think that our senses
are an accurate depiction of the external world
like a window or a camera.
Many great philosophers throughout history
thought that everything we can know
we know through our senses, taste,
hearing, sight, smell, and touch.
So you think that's a bit successful
in the world as us humans clearly are,
it would make the most sense to see the world accurately,
that our ancestors who saw reality clearly
had a competitive advantage over those who didn't,
if you think this is the case, let me show you an image.
Look at these two squares, what color are they?
One looks brown and one looks orange, right?
Well, that's what your eyes are telling you,
it's what they're telling me too.
Now look at what happens when we black out
the rest of the image, the two squares
are in fact exactly the same color.
Because of the way the light was shown,
your brain corrected the image
to what makes sense in the real world,
in other words, your perceptual reality
did not match the objective reality.
Here's another example that you've probably seen.
Back in 2015, a very similar phenomenon
took the internet by storm,
this simple image of a dress quickly became
a viral sensation, so much so that it became known
as the dress that broke the internet, let's see why.
If you haven't seen this before,
what colors do you think the dress is?
Now ask people around you what color they think it is.
It looks white and gold to me,
but to some, this dress appears black and blue.
The reason this image had such an effect on people
was because it revealed differences
in human color perception, something we thought
was an objective property about the world.
We're used to having conflicting opinions about politics,
but about color, this just goes to show
that our sensors like our opinions
are biased and depend on our internal makeup,
a good example of this is colorblindness.
But it's not just our vision that can deceive us,
it's all of our senses.
Listen to this audio clip,
- [Voice over] Brain storm, green needle.
- [Jade] Each time you hear it,
try to hear either brainstorm or green needle.
- [Voice over] Brain storm, green needle.
- [Jade] Which one do you hear?
- [Voice over] Brain storm, green needle.
- [Jade] You hear whichever one you want to hear,
your perception is influenced by your state of mind,
by what you're expecting to hear.
- [Voice over] Brain storm, green needle.
- These are just a few examples of how our experiences
depend more on what we're expecting,
than what's actually there.
But not only are our senses easily deceived,
they're also incredibly limited.
The German word umvelt refers to the different way
that each animal sees the world,
dogs for example, don't see in colors but in smells,
bats don't see at all, but hear their environment,
every animal has an umvelt including us.
We like to think that what we see
is the objective external reality,
but it is just in fact another umvelt.
We can see the entire visible spectrum of light,
but that's by no means the only light that's out there.
Reindeer can see ultraviolet light,
and bumblebees can sense radiation in the UV spectrum,
birds have twice the number of color receptors
in their retinas than we do,
and mantis shrimp can even see
which direction light is vibrating.
By now, you're hopefully convinced
that at least some of the time
we don't see reality as it truly is.
Now, this brings us to the next question,
how, (bell chimes)
how is it that we don't see what's actually there?
(guitar music)
Anil Seth, a British professor
of cognitive and computational neuroscience
at the University of Sussex,
claims that everything that we can see
is a construction of the brain,
what he calls controlled hallucinations.
It's no secret that our brains are capable
of making us see and hear things that just aren't there,
ask anyone who's taken recreational drugs.
They'll often report to hearing things
that don't make sense, or seeing things
they know couldn't possibly exist.
The same is true mentally ill people,
though they don't always know they're hallucinating.
But Seth claims that all of us are always hallucinating,
we just agree on the hallucination.
- Instead of perception depending largely
on signals coming into the brain from the outside world,
it depends as much if not more,
on perceptual predictions flowing in the opposite direction.
We don't just passively perceive the world,
we actively generate it.
The world we experience comes as much
if not more from the inside out as from the outside in.
- It might be helpful to clear up here exactly
what we mean by hallucinations.
Hallucinations don't always need to be
crazy colorful visions or magical flying beings,
the word simply means an experience involving
the apparent perception of something not there.
So how does this happen?
Well, what if I told you that just 10%
of the information that we use to see comes from our eyes,
and the other 90% is filled in by our brains?
An example of this is blind spots.
The retina, right at the back of your eye
contains millions of tiny light detectives
called rods and cones, this is how we see.
They cover the entire retina,
except for a spot where the optic nerve
connects to the brain, this is a blind spot.
As there are no photo receptors,
so no light can be detected there,
now your brain fills in these blind spots
so you don't notice them,
if you don't believe me just look at this.
Cover you'll right eye and look at the green dot,
slowly move your head towards the picture.
(bright music)
At one point the red dot will disappear,
and your brain will fill in the space with white.
It doesn't look like any of the image is missing,
your brain actually fills it in
with something that isn't there.
This is a slightly different example
of a controlled hallucination of your brain presenting you
with something that isn't there.
Notice that the two desert scenes at the bottom
are basically the same, just flipped,
now stare at the dot between the red and green,
don't look anywhere else.
As you're staring at that dot,
your brain is learning that the left side
of its visual field is on the green light,
and the right side is under red lights,
that's becoming its new reality.
Now, when I tell you to not yet,
I want you to look at the dot between the desert scenes,
we need a bit more time for your brain
to get used to its new reality,
so to stop things getting awkward
I'll sing a quick song I made up.
♪ Red and green in the desert scene ♪
♪ Green and red are in your head. ♪
Okay that's enough of that.
Now look at the dot between the two desert scenes,
do they still look the same?
The one on the left should look reddish,
and the one on the right should look greenish, weird huh?
You're seeing with your brain not with your eyes,
take a moment to let that sink in.
Even though these were just demonstrations,
Seth claims that your brain is doing this all the time,
and not just with sight but with all your senses.
The great Italian astronomer Galileo Galilee once said,
"I think that taste, odors, colors,
and so on reside in consciousness,
hence, if the living creature were removed
all these qualities would be annihilated."
So if you're not seeing the raw information
that's actually there, what are you seeing?
Well as neuroscientists and renowned expert
in perception Beau lotto says.
- What you see is a meaning
that was useful to see in the past.
You see what we call the empirical significance
of information, you see the behavioral value
of the data not the data.
- In the example of the desert scene,
it useful at one point for our brains to perceive
that the left side of its visual field was under green light
and the right side was under red lights,
so when we adjusted our gaze, our brain assumed that,
"Hey if it was useful in the past,
it's probably still useful now."
Another example of this is the fact
that hills appear to look steeper to us
if we're wearing a heavy backpack,
we are literally seeing the extra effort it's going to take,
we see the meaning of the information
not the information itself.
This brings us to our next question, why?
We've talked about the fact that our brains
often deceived us, and we've talked about how,
but why would they do this?
(bright upbeat music)
It's counter-intuitive to think
that evolution favors those who don't see reality as it is,
but that's exactly what cognitive psychologist
and bestselling author Donald Hoffman says is the case.
- The assumption is that evolution
has shaped us so that our constructions match the truth,
and I'm gonna argue against that,
the evolution shaped us with a user interface
that hides the truth, nothing that we see as the truth.
The very language of space, and time, and objects
is the wrong language to describe reality,
and that that's very useful, and that's why we're here
- But how could this be?
How could not experiencing reality
as it really is be more useful to us?
Intuitively, it seems that being able
to experience reality accurately,
would make you more capable of surviving in it.
Well, here Hoffman tells a tale
of the Australian jewel beetle.
This is a male jewel beetle living in Outback Australia,
and he's out looking for a female to mate with.
Female jewel beetles are shiny, dimpled, and brown.
Now, Aussie is living in the Outback love a good beer,
and it just so happens that beer bottles
are also shiny, dimpled, and brown.
Now, some irresponsible people just toss
the bottles out when they're done with them,
and sadly the male jewel beetles try
to mate with them thinking they're females.
If that's not sad enough, ants have learned to hang around
near beer bottles and wait for the confused beetles,
then devour them genitalia first.
This blunder of the beetle is surprising,
this species has survived for thousands of years,
you would think that surely they know
their females from the glass bottle.
Yet Australia had to change its beer bottle design
to stop the beetle from going extinct,
so why should a beetle fall for a bottle?
Well the answer is according to Hoffman,
that it was using simple shortcuts and tricks,
apparently a female jewel beetle is anything
that is shiny, dimpled, and brown,
but surely we're different from the beetle, right?
They have tiny brains and are nowhere near as complex as us,
surely mammals with their bigger brains
wouldn't make such silly mistakes.
Well, moose in Alaska, Montana and elsewhere
have been found and photographed
mating with metal statues of moose and even bison,
sometimes for hours on end.
They're using simple shortcuts and tricks to survive.
Observations like this led Hoffman to the hypothesis
that evolution fate is fitness over accuracy.
Fitness refers to a species capability
to reproduce and survive, while accuracy refers
to a species capability to save the world accurately.
It's important to mention here
that this is a very strong position
and it's not the prevailing consensus
among neuro and cognitive scientists.
A lot of them do in fact believe that our senses
epict an objective external world.
At the moment the fitness over accuracy hypothesis
is still exactly that, a hypothesis.
Hoffman does go into it further
and make more arguments for it in his book
"A Case Against Reality", if you'd like to read more
about it, I've linked to the book below.
But this hypothesis does lead to a few puzzling questions,
like how could it possibly be advantageous
for us to not see the world accurately?
And if we're not seeing the world accurately,
how are we all seeing the same thing?
Well, Hoffman answers all these questions
with a simple and elegant analogy,
he compares our experience to a desktop interface.
Suppose that you are writing an email,
and the icon for that email is blue and rectangular
and in the middle of the desktop screen,
does that mean that the email itself
is blue, rectangular, and in the middle of the screen?
Of course not, anybody who thought that
completely misunderstands the point
of the desktop interface.
It's not there to show you reality,
the circuits, the bits, the electric pulsars
that are really what the email is.
If you had to toggle voltages,
your friends would never hear from you, it's just too hard.
What evolution has done is give us a user interface,
it lets you control reality without actually seeing reality,
and this is how it's useful
not to see reality as it really is,
it's also the reason why we're all seeing the same thing.
Even though it desktop isn't the reality
of what's actually going on inside the computer,
we all see the same desktop interface
when we look into API Faisal max.
Even though this is a very strong position to take,
it can't be denied that at least some of the time,
our brain is not showing us true reality.
So what should we do?
Should we just give up on trying
to understand the world around us,
accept that we're just not capable of knowing?
Well, I'm not willing to give up that easily.
This is my very first video
in my quest to understand reality,
it would be pretty pathetic if I just gave up
and was like, "Oh, well I can't."
Sometimes knowing what you don't know
is the first step forward.
I honestly don't know where I'm gonna go from here,
but I do know that I'm going to keep trying
to understand reality, and keep making videos about it,
so I really hope you join me along the way.
In the meantime, some words of encouragement
from Beau lotto are to celebrate doubts,
to embrace the unknown instead of being afraid of it,
that being aware of our biases and limitations
should remind us to constantly question everything,
to question all of our assumptions,
and I think that's a pretty good place to start.
My regular viewers might have noticed
that this video was quite different to what I usually do,
as I mentioned, I had an existential crisis
and this made me wanna understand life and existence,
which naturally led me to philosophy.
This video was just the first of a philosophy series
that I'm studying on Nebula.
Nebula is a streaming video platform
built by and for independent creators like CGP Gray,
Brian Croft, MinutePhysics,
Knowing Better, and Real Engineering.
We are building Nebula because we want a place
for educational creators to try out new content ideas
that might not work on YouTube, like my philosophy series.
Normally Nebula is $3 a month,
but we've partnered with our friends
at Curiosity Stream to get youth free access to Nebula
with a Curiosity Stream subscription.
Curiosity Stream is a subscription streaming service
with thousands of high quality documentaries.
If you liked my recent mini-series on quantum biology,
I'd highly recommend this documentary,
"The Secrets of Quantum Physics",
it explores other instances of quantum biology,
and it's presented by one of the pioneers
of the field himself, Jim Al-Khalili.
Curiosity Stream loves independent creators
and wants to help us grow our platform,
so they're offering Up and Atom viewers
free access to Nebula when you sign up
at CuriosityStream.com/upandatom.
By signing up to Curiosity Stream,
you'll be helping not just me
but the entire community of educational creators.
Nebula is a place where creators
can really make what they're passionate about,
not just what will get a lot of views.
If you'd like to join me in my quest
to understand our wonderful existence,
sign up to Curiosity Stream using
this link which you can find in the description.
Thanks for watching, bye.