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Freeman:
Do we live in the real world?
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[ Alarm clock beeps ]
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Or is it all in our minds?
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Do we see the universe as it is?
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Or do our senses deceive us?
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Scientific observation reveals
hidden realities.
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The judgment of our senses
cannot be trusted.
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[ Engine revs ]
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And our basic assumptions
about life and the universe
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may be false.
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Is existence an illusion?
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Is reality real?
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Space, time, life itself.
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The secrets of the cosmos
lie through the wormhole.
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Subtital By RA_One
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What is real?
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We assume it's everything we
encounter in our daily lives.
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But how can we be certain
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the universe we see around us
actually exists?
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And how can we know
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that the world we see matches
what anyone else experiences?
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Our senses certainly make
reality seem real enough.
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These things are solid.
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But...
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What if they actually aren't?
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Our reality may be
a fragile tissue of illusions
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illusions about ourselves,
our society,
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and even the whole
of the natural world.
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When I was young,
a magician came to town.
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He was pretty good.
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Watching him made me doubt
the reliability of my own eyes.
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No matter how hard I looked,
I couldn't see how he did it.
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What was I missing?
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And why was I missing it?
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Lawrence rosenblum
is a Professor
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of perceptual psychology
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at the university of California,
riverside.
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He also dabbles in magic.
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More than most,
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Larry understands the mechanisms
magicians use to warp reality.
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Man: Ladies and gentlemen,
the amazing Larry!
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Rosenblum: Good evening,
ladies and gentlemen.
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Tonight, I'd like to teach you
a little bit about perception.
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How did that trick work?
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Well, as I was throwing
the ball up,
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you were following my eyes
with your attention.
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And that continued
through the last throw,
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which was not a real throw.
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That technique of misdirection
is just one
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of the many techniques
that professional magicians use.
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Freeman:
Illusionists like David gabbay
perform tricks
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that fool us again and again,
no matter how closely we watch.
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They take advantage
of our brain's eagerness
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to make sense of the world.
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Rosenblum: David's not helping
our brains create a reality
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as much as guiding our attention
of the perceptual information
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in different ways.
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And in that way, I think that
David has a lot to teach us.
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Freeman: David's trick exploits
a mental shortcut
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called amodal completion.
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Here is how it works.
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Let's say you see a rabbit.
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Then your view of the rabbit
is partially blocked.
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Is the rabbit still there?
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Of course.
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You know that
because your brain matches it up
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with a three-dimensional model
of a rabbit
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you have filed in your memory.
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Your brain fills in
the missing piece.
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Voilà!
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Freeman:
We have millions of these models
stored in our minds.
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We use them to assemble
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a seemingly continuous picture
of the world
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what we think of as reality.
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Our sense of reality is
profoundly affected
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by the way
our senses work together.
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For instance...
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Bah, bah, bah, bah...
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Freeman: What do you hear?
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Bah, bah, bah...
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Larry seems to be saying,
"Bah, bah, bah."
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but here's what happens when the
picture is changed just a bit.
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Fah, fah, fah, fah...
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Freeman: Now it sounds like
he is saying, "Fah, fah, fah."
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but close your eyes and listen.
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The sound hasn't changed.
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Larry is still saying,
"Bah," With a "B."
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bah, bah, bah.
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In the case with an auditory
"Bah" And a visual "Vah,"
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what happens is
the visual information ends up
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overriding
the auditory information
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because it's so salient.
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It is so easy to see.
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Bah, bah, bah.
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And the perceptual brain,
in this case,
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mostly the auditory brain
ends up using that information
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to kind of push the "Bah"
To sound more like a "Vah,"
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and that's what people
end up believing
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they're actually hearing.
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Freeman: Many different sensory
systems interact within our brains.
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Our minds take this information
and tell a story about it.
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We call it reality.
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We're perceiving a lot more
than we realize.
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And what I mean by that is
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that there are entire channels
of information
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that are getting to the brain
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underneath our level
of awareness.
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But at any one time,
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not only are you
seeing something
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and attending
to what you're seeing,
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but what you're not attending to
is affecting you as well,
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and that isn't just
from information
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you get through your eyes,
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but information
you get through your ears
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and through your nose
and through your skin.
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And all of that is happening
as we're sitting there
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experiencing what we think is
a visual reality.
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The other senses
are affecting it all.
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Freeman:
But for all we perceive,
there is much we miss.
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Most of us share
the same set of senses.
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Yet some of us see things
very differently than others.
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Can any of us perceive the world
as it truly is?
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Professor Charles Falco is
one of the few who can.
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He explores the invisible world
the reality we can't see.
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[ Camera shutter clicking ]
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The human vision system only
captures a really tiny fraction
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of the light that's available.
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If we look at a bust like this,
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we see it looks red
to the naked eye.
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But if we image this
in the ultraviolet,
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possibly,
this bust will fluoresce
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because of some of the chemical
composition that's in it.
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Infrared typically penetrates
fairly far through red pigment.
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So we'll be able to see
what's underneath the pigment,
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if there's something
between the pigment
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and the plaster bust itself.
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Freeman: In his laboratory
at the university of Arizona,
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Charles had exotic instruments
that can examine objects
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at resolutions across all ranges
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of visible
and invisible light
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x-rays, ultraviolet, infrared,
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and machines that see
millions of times sharper
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than human eyes.
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This electron microscope can
read the rough molecular surface
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of the bust's
seemingly smooth red paint.
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The crown jewel
of his collection
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is a machine that reads
the space between atoms,
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giving physicists
a completely different way
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of looking at how molecules
are constructed.
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Falco:
If you only have your eyes,
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you look at something,
you think you understand it.
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Turns out that the more tools
you have to look at something,
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it reveals
much more information.
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So reality is
a much more complex thing
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than we think about.
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The more ways we have
studying of reality,
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the more we realize reality is
a bigger picture
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than we could possibly
have understood before.
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Freeman: There is no
evolutionary pressure
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to create an animal that sees
reality as it really is.
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We have evolved to see
the reality we need to see.
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When we see something,
how our brain interprets it
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isn't usually what exactly
is imprinted on our eyeball.
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We're not a camera.
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We have a brain
behind our retinas.
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And the brain processes
the information
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and tells us
what it wants us to see.
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There is so much
visual information
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in the world around us
that it turns out
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our brain gives us a limited
spotlight of attention,
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where we focus our attention on
exactly what's in front of us,
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ignoring things
that go on everywhere else.
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Freeman: When your attention's
attracted by something,
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neurons enhance the sensitivity
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of the central region
of your field of vision
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and suppress the sensitivity
of the surrounding regions.
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And this is how we see
the world through binoculars.
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We see only a tiny fraction
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of the reality
that's in front of us.
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There is so much
sensory information,
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so much visual information
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that, in fact, it's impossible
to process it all.
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So everyone's brain,
every animal's brain
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has been programmed by evolution
to accept
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only a small fraction of
the information and process it.
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Otherwise,
there'd be total overload.
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Freeman:
But reality isn't defined solely
by how you or I see the world
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it's something we share.
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We check our observations
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against the observations
of others.
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If we didn't agree
on what is real and what is not,
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society couldn't function.
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But this man believes
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our shared reality
is the greatest illusion of all.
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I am not real.
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You are looking at thousands
of glowing, colored dots
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on a screen.
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The pattern of these dots
changes
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once every 30th of a second,
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creating the illusion
of movement.
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And I'm not saying these words
right now.
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This is a captured impression
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of something I said
in the recent past.
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Or is it?
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What if I did this?
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You've been conditioned
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to believe that,
when something says "Live,"
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it's really happening right now.
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Our society is tied together
by these shared beliefs.
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But how much of it is real?
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And how much is
just an elaborate fantasy?
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For much of his life,
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scientist and philosopher
Jim baggott has been haunted
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by a simple question
what is reality?
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All reality is a fantasy
created in our own heads.
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We are locked in the prison
of our own minds,
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and as a consequence,
we have to create for ourselves
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an understanding
of what reality is like
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on the basis
of what we can absorb,
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what we can learn,
what we can see.
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[ Door creaks ]
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So when we see with our eyes,
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what we perceive, of course,
is not reality as such.
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Our brains are, after all,
just clumps of tissue
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weighing about 3½ pounds, with
a consistency of cold porridge.
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It's only when we interpret
the electrical signals
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generated by our brain
in our conscious mind
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do we create
our individual reality.
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That begs the question
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what happens when those
electrical signals are shut off?
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Well, I'm about to find out.
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Freeman:
Jim's going to have his hearing
and vision blocked out
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for 15 minutes.
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This simple form
of sensory deprivation
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sends him
into an alternate reality.
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He loses track of time...
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[ Alarm clock rings ]
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...and experiences
vivid hallucinations.
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In the absence of sensory input,
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Jim's world-making machinery
manufactures a reality
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with no connection
to the world outside his body.
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Baggott: Deprived of two
of my most important senses,
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what happens is
the brain scrambles for inputs
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from other senses.
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So you become very conscious
of the taste in your mouth
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and the hardness of this bed
that I'm lying on.
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I began to drift
into some dreamlike states.
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But then I became aware
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that me eyes are,
in fact, wide open,
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and I'm fully awake
and conscious.
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Freeman:
When your senses are shut off,
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your brain makes up
its own version of reality.
254
00:13:39,958 --> 00:13:45,697
But according to Jim, we all
live in a false reality
255
00:13:45,697 --> 00:13:48,566
a hyperreality created
by society,
256
00:13:48,566 --> 00:13:52,237
filled with illusions
that have become more real to us
257
00:13:52,237 --> 00:13:55,873
than the physical world
around us.
258
00:13:55,874 --> 00:14:01,446
We are all part
of a community of minds,
259
00:14:01,446 --> 00:14:06,117
a world created by billions
of brains working in concert
260
00:14:06,117 --> 00:14:08,185
over thousands of years.
261
00:14:08,186 --> 00:14:10,789
The modern consumer society
262
00:14:10,789 --> 00:14:14,326
is the latest twist
our mass mind has evolved
263
00:14:14,326 --> 00:14:17,329
to advance the species.
264
00:14:17,329 --> 00:14:20,864
Money lies at the heart
of this society.
265
00:14:20,865 --> 00:14:22,467
But in many ways,
266
00:14:22,467 --> 00:14:27,639
it is the most hyperreal
of all of our creations.
267
00:14:27,639 --> 00:14:31,476
Baggott: I have here a $50 bill
and a 50£ note.
268
00:14:31,476 --> 00:14:34,912
Current currency-conversion
rates tells us that the pound
269
00:14:34,912 --> 00:14:38,050
is about 1½ times greater
in value than the dollar.
270
00:14:38,050 --> 00:14:41,151
And these little pieces of paper
hold such a spell
271
00:14:41,152 --> 00:14:42,186
over our lives.
272
00:14:42,186 --> 00:14:44,256
They tell us whether
almost
273
00:14:44,256 --> 00:14:46,324
who is gonna live,
who is gonna die.
274
00:14:46,324 --> 00:14:48,425
But, really, value is something
275
00:14:48,426 --> 00:14:51,696
that's part of the hyperreality
that we've created,
276
00:14:51,696 --> 00:14:54,566
and I don't know what the real
value of a piece of paper
277
00:14:54,566 --> 00:14:57,702
made of three parts cotton fiber
and one part linen really is,
278
00:14:57,702 --> 00:15:02,107
but I can tell you
it's a lot less than $50 or 50£.
279
00:15:04,676 --> 00:15:10,114
Freeman:
Money would be valueless
if we didn't all believe in it.
280
00:15:10,114 --> 00:15:12,451
Our shared reality is
an illusion
281
00:15:12,451 --> 00:15:14,519
we have to struggle to maintain.
282
00:15:14,519 --> 00:15:18,089
And if we fail
to strictly observe its rules,
283
00:15:18,089 --> 00:15:21,693
reality can crumble.
284
00:15:21,693 --> 00:15:23,795
Baggott: Once these structures
are out there, as it were,
285
00:15:23,795 --> 00:15:26,131
they develop,
you know, laws of their own.
286
00:15:26,131 --> 00:15:28,833
They develop
a life of their own almost.
287
00:15:28,833 --> 00:15:31,336
And that misinterpreting
those rules
288
00:15:31,336 --> 00:15:33,838
and distorting those rules
and changing those rules
289
00:15:33,838 --> 00:15:36,373
we do that at our peril.
290
00:15:36,374 --> 00:15:39,310
Freeman: There is perhaps
no greater example
291
00:15:39,310 --> 00:15:43,146
than the recent near collapse
of the global financial system.
292
00:15:43,147 --> 00:15:44,649
[ Atm beeping ]
293
00:15:44,649 --> 00:15:47,052
Baggott: The global
banking crisis of 2008
294
00:15:47,052 --> 00:15:50,388
resulted from bankers playing
with the rules of the game.
295
00:15:50,388 --> 00:15:51,722
And as a consequence,
296
00:15:51,722 --> 00:15:56,394
the value of money, literally
overnight, was destroyed.
297
00:15:56,394 --> 00:15:57,795
[ Bell ringing ]
298
00:15:57,795 --> 00:15:59,930
Woman: Wall street is a panic
after a record drop.
299
00:15:59,931 --> 00:16:02,433
Freeman: For a brief moment,
people became conscious
300
00:16:02,433 --> 00:16:06,404
that money is essentially
an illusion.
301
00:16:06,404 --> 00:16:10,275
But if we stop believing
in the global monetary system,
302
00:16:10,275 --> 00:16:12,510
society could collapse.
303
00:16:12,510 --> 00:16:16,114
So we choose
to keep on believing.
304
00:16:16,114 --> 00:16:19,017
Civilization was brought
almost to its knees.
305
00:16:19,017 --> 00:16:21,618
But the fact that civilization
didn't disappear
306
00:16:21,619 --> 00:16:23,621
perhaps tells us
that hyperreality,
307
00:16:23,621 --> 00:16:26,291
despite the fact that it exists
only in our minds,
308
00:16:26,291 --> 00:16:29,493
is still too tough to kill.
309
00:16:29,494 --> 00:16:33,298
Freeman:
Why is it so easy for us
to live in a fantasy world?
310
00:16:33,298 --> 00:16:35,934
What is it about being human
311
00:16:35,934 --> 00:16:39,937
that compels us
to create a hyperreality?
312
00:16:39,937 --> 00:16:42,506
Is it social pressure?
313
00:16:42,506 --> 00:16:43,574
[ Baby crying ]
314
00:16:43,574 --> 00:16:45,810
Or is it born into us?
315
00:16:45,810 --> 00:16:49,046
This neuroscientist believes
the answer is buried
316
00:16:49,047 --> 00:16:50,915
deep in our brains
317
00:16:50,915 --> 00:16:55,051
and our denial of reality
may be essential
318
00:16:55,052 --> 00:16:59,592
to the survival of our species.
319
00:17:00,000 --> 00:17:04,372
The human brain is
a storyteller.
320
00:17:04,372 --> 00:17:07,842
It tells us tales
about the way things are,
321
00:17:07,842 --> 00:17:12,513
and it allows us to imagine
the way things could be.
322
00:17:12,513 --> 00:17:18,219
But what if the stories
we tell ourselves aren't true?
323
00:17:18,219 --> 00:17:20,554
How would we know?
324
00:17:20,554 --> 00:17:25,559
What if all our brains are wired
to lie about reality
325
00:17:25,559 --> 00:17:29,063
and our place in it?
326
00:17:32,333 --> 00:17:34,534
This man is about to ride
his motorcycle
327
00:17:34,534 --> 00:17:37,004
through the traffic-clogged
streets of London.
328
00:17:37,004 --> 00:17:42,008
When he does, he will enter
an alternate reality.
329
00:17:42,008 --> 00:17:43,809
[ Engine turns over ]
330
00:17:43,810 --> 00:17:45,513
[ Engine revs ]
331
00:17:47,781 --> 00:17:50,451
Motorcyclists make up
less than one percent
332
00:17:50,451 --> 00:17:54,453
of vehicle traffic in britain.
333
00:17:54,454 --> 00:17:58,826
But they suffer 14% of total
deaths and serious injuries.
334
00:17:58,826 --> 00:18:02,663
Bikers in the U.S. are
about 37 times more likely
335
00:18:02,663 --> 00:18:05,832
to die in a crash
than people in a car.
336
00:18:05,832 --> 00:18:07,167
[ Siren wails ]
337
00:18:07,167 --> 00:18:10,804
But in this man's reality,
those numbers don't apply,
338
00:18:10,804 --> 00:18:13,307
at least not to him.
339
00:18:13,307 --> 00:18:16,376
Despite knowing
the grim statistics,
340
00:18:16,377 --> 00:18:19,312
he, like millions
of other bikers,
341
00:18:19,312 --> 00:18:24,051
continues
to ride his motorcycle.
342
00:18:24,051 --> 00:18:29,123
Why do so many people
consistently disregard risk?
343
00:18:29,123 --> 00:18:31,357
At university college London,
344
00:18:31,358 --> 00:18:34,628
neuroscientist tali sharot
has discovered
345
00:18:34,628 --> 00:18:37,264
there's a reality-distortion
mechanism
346
00:18:37,264 --> 00:18:39,833
built into the human brain.
347
00:18:39,833 --> 00:18:45,238
She wrote a book about it
called "The optimism bias."
348
00:18:45,238 --> 00:18:46,707
so the optimism bias
349
00:18:46,707 --> 00:18:49,643
is our tendency to overestimate
the positive things in our lives
350
00:18:49,643 --> 00:18:52,980
and underestimate the likelihood
of negative things in our lives.
351
00:18:52,980 --> 00:18:54,280
So, for example,
352
00:18:54,281 --> 00:18:57,485
people overestimate
their success professionally,
353
00:18:57,485 --> 00:18:59,085
their longevity.
354
00:18:59,085 --> 00:19:00,921
They underestimate
their likelihood
355
00:19:00,921 --> 00:19:04,324
of suffering from cancer,
of getting divorced.
356
00:19:04,324 --> 00:19:06,426
We are more optimistic
than realistic,
357
00:19:06,426 --> 00:19:08,662
but most of us are oblivious
to the fact.
358
00:19:08,662 --> 00:19:10,764
We're not aware of it.
359
00:19:10,764 --> 00:19:15,769
Freeman:
Nearly 80% of the population
is affected by this bias.
360
00:19:15,769 --> 00:19:17,770
It's easy to see it in action,
361
00:19:17,771 --> 00:19:21,575
as tali demonstrates
with a random group of students.
362
00:19:21,575 --> 00:19:24,778
So, I'm gonna give you a list of
abilities and characteristics,
363
00:19:24,778 --> 00:19:27,079
and I want you to think,
for each of these abilities,
364
00:19:27,080 --> 00:19:29,916
where you stand relative
to the rest of the population.
365
00:19:29,916 --> 00:19:33,019
So, the first one is
getting along well with others.
366
00:19:33,019 --> 00:19:35,521
Who believes they are
at the bottom 25%?
367
00:19:35,522 --> 00:19:38,692
Okay. No one. [ Chuckles ]
368
00:19:38,692 --> 00:19:42,730
Who thinks
they are at the top 50%?
369
00:19:42,730 --> 00:19:45,231
Okay. So that's most people.
370
00:19:45,232 --> 00:19:46,767
So, what we find is
371
00:19:46,767 --> 00:19:50,971
that most people rate themselves
above average on most abilities.
372
00:19:50,971 --> 00:19:52,573
And that's, of course,
statistically impossible,
373
00:19:52,573 --> 00:19:55,075
'cause we can't all be
better than everyone else.
374
00:19:55,075 --> 00:19:58,612
Who here thinks that they will
have talented kids?
375
00:19:58,612 --> 00:20:02,048
That's most of us here.
376
00:20:02,049 --> 00:20:05,152
And who here thinks
they will be successful
377
00:20:05,152 --> 00:20:07,520
in their professional life?
378
00:20:15,095 --> 00:20:16,997
Freeman:
It's commonly believed
379
00:20:16,997 --> 00:20:19,633
that, when your expectations
are not met,
380
00:20:19,633 --> 00:20:22,068
you alter your expectations.
381
00:20:22,069 --> 00:20:24,638
Yet tali's experiments show
that most people,
382
00:20:24,638 --> 00:20:27,474
despite all evidence
to the contrary,
383
00:20:27,474 --> 00:20:32,913
remain optimistic
in the face of reality.
384
00:20:32,913 --> 00:20:36,915
She decided to find out why.
385
00:20:36,916 --> 00:20:38,886
Using a brain scanner,
386
00:20:38,886 --> 00:20:41,055
tali monitors
what happens in our heads
387
00:20:41,055 --> 00:20:43,557
when we process information.
388
00:20:43,557 --> 00:20:46,092
Today, this man will learn
389
00:20:46,092 --> 00:20:50,163
if he's out of touch
with the real world.
390
00:20:50,163 --> 00:20:52,399
Sharot: Okay, so you're gonna
see the negative life events,
391
00:20:52,399 --> 00:20:53,633
such as cancer,
392
00:20:53,633 --> 00:20:56,336
and what you need to do is
estimate your likelihood
393
00:20:56,336 --> 00:20:59,339
of experiencing this event
in your lifetime.
394
00:20:59,340 --> 00:21:01,474
Then you will see
the average likelihood
395
00:21:01,474 --> 00:21:03,777
of someone like you
experiencing that event.
396
00:21:03,777 --> 00:21:08,716
Freeman: Nick the biker will be
asked to calculate his chances
397
00:21:08,716 --> 00:21:13,653
of experiencing 80 different
negative events in the future.
398
00:21:13,653 --> 00:21:15,855
Nick thinks his chances
of getting lung cancer
399
00:21:15,856 --> 00:21:18,525
are about 10%.
400
00:21:18,525 --> 00:21:22,829
Actually, it's 30% for a man
of his age and lifestyle.
401
00:21:22,829 --> 00:21:26,066
Now he's presented
with more negative events.
402
00:21:26,066 --> 00:21:28,168
With each new scenario,
403
00:21:28,168 --> 00:21:33,373
he gives a prediction before
finding out the real statistic.
404
00:21:33,373 --> 00:21:35,308
When Nick hears good news,
405
00:21:35,309 --> 00:21:39,646
his brain scans show plenty of
activity in the frontal lobes.
406
00:21:39,646 --> 00:21:43,218
But when he hears bad news,
there is much less activity.
407
00:21:44,718 --> 00:21:47,287
Now Nick will
take the test again
408
00:21:47,387 --> 00:21:50,892
to see whether these facts
have changed his beliefs.
409
00:21:51,000 --> 00:21:53,536
Sharot: What we usually find,
again and again,
410
00:21:53,536 --> 00:21:56,573
is that people change
their estimates quite a lot
411
00:21:56,573 --> 00:22:00,709
in the second session for items
where they got information
412
00:22:00,710 --> 00:22:02,945
that was better
than their own estimates.
413
00:22:02,945 --> 00:22:04,581
So, for example, if Nick says
414
00:22:04,581 --> 00:22:08,084
that his likelihood of suffering
from Alzheimer's is about 30%,
415
00:22:08,084 --> 00:22:09,485
and we tell him,
416
00:22:09,485 --> 00:22:11,988
well, the average likelihood
of Alzheimer's is only 10%,
417
00:22:11,988 --> 00:22:14,190
we find that most people
change their estimates
418
00:22:14,190 --> 00:22:15,490
the second time around.
419
00:22:15,491 --> 00:22:17,359
They would say, "Well,
maybe my average likelihood
420
00:22:17,359 --> 00:22:19,895
of Alzheimer's
is only about 12%."
421
00:22:19,895 --> 00:22:23,066
and we see,
in the frontal lobes,
422
00:22:23,066 --> 00:22:26,435
enhanced activity
when people get information
423
00:22:26,435 --> 00:22:28,504
that's better
than what they expected.
424
00:22:30,372 --> 00:22:34,043
Freeman:
But when people get information
that's worse than expected,
425
00:22:34,043 --> 00:22:36,546
it doesn't sink in.
426
00:22:36,546 --> 00:22:41,549
Despite being told he has a 30%
chance of dying of lung cancer,
427
00:22:41,550 --> 00:22:47,757
Nick barely changes his estimate
from 10% to 13%.
428
00:22:47,757 --> 00:22:52,628
Our brains seem
to resist negative information,
429
00:22:52,628 --> 00:22:55,764
but only when it applies to us.
430
00:22:55,764 --> 00:22:58,300
Sharot: So we're mostly
optimistic about ourselves,
431
00:22:58,300 --> 00:23:01,203
and we're optimistic about
our kids, about our families,
432
00:23:01,203 --> 00:23:03,940
but we're not optimistic
about other people.
433
00:23:03,940 --> 00:23:06,542
So people tend to be
even slightly pessimistic
434
00:23:06,542 --> 00:23:09,812
about the future of the country
and the future of the world.
435
00:23:09,812 --> 00:23:12,982
People do have
quite pessimistic expectations
436
00:23:12,982 --> 00:23:15,250
of where the economy is going,
for example,
437
00:23:15,250 --> 00:23:17,620
but they tend to think
that they will be okay.
438
00:23:17,620 --> 00:23:22,224
Freeman:
And this is why the warnings on
cigarette packages go unheeded.
439
00:23:22,224 --> 00:23:26,195
Yes, smoking kills
six million people a year.
440
00:23:26,195 --> 00:23:29,865
But smokers believe
that it kills the other guy.
441
00:23:29,865 --> 00:23:33,102
They are unique.
They will survive.
442
00:23:33,102 --> 00:23:34,804
[ Inhales deeply ]
443
00:23:34,804 --> 00:23:38,940
Freeman: That's the downside
of living in a false reality.
444
00:23:38,941 --> 00:23:42,178
But there is a strong
positive aspect to it, as well.
445
00:23:42,178 --> 00:23:45,681
So, optimism changes
the way we see the world.
446
00:23:45,681 --> 00:23:47,149
Man: Nelson mandela!
447
00:23:47,149 --> 00:23:50,619
Sharot: But it also changes
objective reality.
448
00:23:50,619 --> 00:23:54,390
And it does so because it acts
as a self-fulfilling prophecy.
449
00:23:54,390 --> 00:23:58,928
So positive expectations changes
our actions and our interactions
450
00:23:58,928 --> 00:24:00,796
with the people around us,
with the world,
451
00:24:00,797 --> 00:24:03,966
and that actually changes
the world around us.
452
00:24:03,966 --> 00:24:08,571
Freeman:
And this reality-distortion
field, tali believes,
453
00:24:08,571 --> 00:24:12,408
is essential to the survival and
advancement of the human race.
454
00:24:12,408 --> 00:24:16,812
Hope may not always be
realistic,
455
00:24:16,812 --> 00:24:20,983
but it makes the world
a better place.
456
00:24:22,418 --> 00:24:26,789
We all live in many realities.
457
00:24:26,789 --> 00:24:29,692
There is the reality
in our minds,
458
00:24:29,692 --> 00:24:33,295
and there is the reality
we share with others.
459
00:24:33,295 --> 00:24:37,499
We now know these realities
can't be entirely trusted.
460
00:24:37,500 --> 00:24:40,035
But what about
the physical world
461
00:24:40,035 --> 00:24:43,104
that exists
outside of our minds?
462
00:24:43,105 --> 00:24:44,373
Surely,
463
00:24:44,373 --> 00:24:47,910
in the rock-solid cause-
and-effect world of nature,
464
00:24:47,910 --> 00:24:53,082
we can rely on things
to be indisputably real.
465
00:24:56,785 --> 00:24:58,454
Maybe not.
466
00:25:01,000 --> 00:25:07,674
In many ways, we are blind
to the true nature of reality.
467
00:25:07,674 --> 00:25:11,143
Our perceptions are limited.
468
00:25:11,143 --> 00:25:15,314
Our brains distort the truth.
469
00:25:15,314 --> 00:25:18,450
So can we ever know
what is real?
470
00:25:18,451 --> 00:25:21,220
That's the mission of science
471
00:25:21,220 --> 00:25:24,657
to probe deep into the massive
puzzle box of nature
472
00:25:24,657 --> 00:25:27,827
to find its ultimate truths.
473
00:25:27,827 --> 00:25:31,364
But how successful have we been?
474
00:25:31,364 --> 00:25:37,870
What if we are blind to an
entire extra dimension of space?
475
00:25:38,800 --> 00:25:41,972
There are two kinds
of physicists
476
00:25:42,000 --> 00:25:44,769
theoreticians,
who make informed guesses
477
00:25:44,769 --> 00:25:47,538
as to why the world works
the way it does,
478
00:25:47,538 --> 00:25:50,308
and experimentalists,
479
00:25:50,308 --> 00:25:54,177
who break things apart
to see what's inside.
480
00:25:54,178 --> 00:25:58,149
Steve nahn is
an experimentalist.
481
00:25:58,149 --> 00:26:01,285
I absolutely believe
that reality is a real thing,
482
00:26:01,285 --> 00:26:04,121
but that does not mean that we
completely understand it.
483
00:26:04,121 --> 00:26:06,891
When you look at the first maps
of the world,
484
00:26:06,891 --> 00:26:10,494
what you notice immediately is
there are major pieces missing.
485
00:26:10,494 --> 00:26:11,962
But as we explored more,
486
00:26:11,962 --> 00:26:15,032
our accuracy on the maps got
much, much better,
487
00:26:15,032 --> 00:26:16,533
and we discovered continents,
488
00:26:16,534 --> 00:26:19,337
like the americas
or Antarctica or Australia.
489
00:26:19,337 --> 00:26:23,007
Today, thanks to satellites, our
maps are incredibly accurate.
490
00:26:23,007 --> 00:26:25,843
But when it comes
to the deeper levels of reality,
491
00:26:25,843 --> 00:26:28,246
we're kind of like
those first maps here.
492
00:26:28,246 --> 00:26:30,482
We don't know
everything that's out there.
493
00:26:34,018 --> 00:26:37,922
Freeman: Physicists map
the subatomic levels of reality
494
00:26:37,922 --> 00:26:41,259
using the large hadron collider
in Geneva.
495
00:26:41,259 --> 00:26:45,663
The lhc is the biggest
microscope in the world.
496
00:26:45,663 --> 00:26:48,199
It smashes together protons
497
00:26:48,199 --> 00:26:56,874
at 99.999999 percent
of the speed of light.
498
00:26:56,874 --> 00:27:00,278
Steve was one of the small army
of scientists
499
00:27:00,278 --> 00:27:05,416
who found the signature traces
of the higgs field in July 2012.
500
00:27:05,416 --> 00:27:09,153
The higgs field is responsible
for the existence of matter
501
00:27:09,153 --> 00:27:10,721
in the universe.
502
00:27:10,721 --> 00:27:14,359
But this remarkable discovery
may be just the beginning.
503
00:27:14,359 --> 00:27:20,430
Many more strange things
could emerge from the lhc...
504
00:27:20,431 --> 00:27:23,367
Perhaps even gateways
to unseen new realities.
505
00:27:23,367 --> 00:27:25,703
Huh?
506
00:27:25,703 --> 00:27:29,139
There may be dimensions
of space and time
507
00:27:29,140 --> 00:27:31,475
beyond the ones we know,
508
00:27:31,475 --> 00:27:35,312
dimensions that could explain
one of the greatest mysteries
509
00:27:35,313 --> 00:27:38,315
of physics.
510
00:27:38,315 --> 00:27:40,585
There are
four fundamental forces
511
00:27:40,585 --> 00:27:42,786
that drive everything we know.
512
00:27:42,786 --> 00:27:44,956
There is
the electromagnetic force,
513
00:27:44,956 --> 00:27:47,625
there is the strong force
and the weak force,
514
00:27:47,625 --> 00:27:50,761
and then there's the one
that we know the least about,
515
00:27:50,761 --> 00:27:52,263
and that's gravity.
516
00:27:52,263 --> 00:27:56,000
Gravity is a trillion, trillion,
trillion times weaker
517
00:27:56,000 --> 00:27:58,703
than the scale
of those other forces.
518
00:27:58,703 --> 00:28:01,138
So what's going on with gravity?
519
00:28:01,138 --> 00:28:03,107
Why is it so much weaker?
520
00:28:03,107 --> 00:28:07,344
That's one of the questions we'd
like to be answer at the lhc.
521
00:28:07,344 --> 00:28:11,382
Freeman: Many physicists suspect
the three dimensions we know
522
00:28:11,382 --> 00:28:14,451
are slices
of a much larger universe.
523
00:28:14,451 --> 00:28:17,721
In other, as yet undetected,
dimensions,
524
00:28:17,721 --> 00:28:21,726
gravity may be as strong
as the other three forces.
525
00:28:21,726 --> 00:28:25,596
The proof would be
discovering high-energy clones
526
00:28:25,596 --> 00:28:28,766
of familiar particles.
527
00:28:28,766 --> 00:28:31,335
Nahn: Suppose that you found
some new particles
528
00:28:31,335 --> 00:28:33,537
that were
sort of kissing cousins
529
00:28:33,537 --> 00:28:35,339
to the particles
you love and know,
530
00:28:35,339 --> 00:28:36,940
only at higher mass.
531
00:28:36,940 --> 00:28:38,576
So for each electron,
532
00:28:38,576 --> 00:28:41,246
you have another electron
that's at much higher mass.
533
00:28:41,246 --> 00:28:44,248
And for each quark, you have
another quark at higher mass.
534
00:28:44,248 --> 00:28:46,318
And that would be a signature
for extra dimensions,
535
00:28:46,518 --> 00:28:48,886
and it would actually provide,
possibly, a clue
536
00:28:49,000 --> 00:28:51,003
for what's going on
with gravity.
537
00:28:51,003 --> 00:28:54,172
Because some particles can
travel in this extra dimension,
538
00:28:54,172 --> 00:28:55,674
and some particles cannot.
539
00:28:55,674 --> 00:28:57,776
But if you could go off
in that extra dimension
540
00:28:57,776 --> 00:28:59,077
somewhere further away,
541
00:28:59,077 --> 00:29:02,481
gravity becomes just as strong
as the other forces.
542
00:29:04,516 --> 00:29:08,187
Freeman:
Things would be very different
in this hidden reality.
543
00:29:08,187 --> 00:29:11,890
For one thing,
they would be much heavier.
544
00:29:11,890 --> 00:29:13,891
Nahn: Take this basketball.
545
00:29:13,892 --> 00:29:15,393
Let's pretend
that it is a particle
546
00:29:15,393 --> 00:29:17,028
that can travel
in the extra dimension.
547
00:29:17,028 --> 00:29:20,365
If it's here where we are,
in that extra dimension,
548
00:29:20,365 --> 00:29:23,769
and I drop it,
gravity pulls it to the ground,
549
00:29:23,769 --> 00:29:25,237
and the floor is strong enough
550
00:29:25,237 --> 00:29:27,005
to push it
back up into my hands.
551
00:29:27,005 --> 00:29:28,806
But suppose that it then moves
552
00:29:28,807 --> 00:29:31,309
somewhere else
in this extra dimension,
553
00:29:31,309 --> 00:29:34,012
where gravity grows
exponentially stronger.
554
00:29:34,012 --> 00:29:35,513
If I drop it over there,
555
00:29:35,513 --> 00:29:37,516
the floor wouldn't be
strong enough at all...
556
00:29:38,784 --> 00:29:41,218
...and the ball would go
straight through the ground,
557
00:29:41,219 --> 00:29:43,988
crashing through
the building below us.
558
00:29:43,988 --> 00:29:46,659
Freeman: Back at the large
hadron collider in Geneva,
559
00:29:46,714 --> 00:29:50,384
the beams will soon be smashing
together with enough force
560
00:29:50,384 --> 00:29:52,886
to prove whether or not
561
00:29:52,886 --> 00:29:57,891
this gravity-heavy dimension
actually exists.
562
00:29:57,891 --> 00:30:00,561
The lhc may shake up
the orthodoxy
563
00:30:00,561 --> 00:30:03,664
by proving these theories
right or wrong.
564
00:30:03,664 --> 00:30:06,000
I myself do not take sides.
565
00:30:06,000 --> 00:30:08,635
My job is to find out
what is really there
566
00:30:08,635 --> 00:30:11,172
and what is really not there.
567
00:30:11,172 --> 00:30:13,741
There are
many different possibilities.
568
00:30:13,741 --> 00:30:17,745
Like the mapmakers of old,
we are exploring terra incognita
569
00:30:17,745 --> 00:30:22,649
and trying to draw new maps
of the true nature of reality.
570
00:30:22,649 --> 00:30:26,353
Freeman: The universe may have
more dimensions
571
00:30:26,353 --> 00:30:28,188
than the ones we know.
572
00:30:28,188 --> 00:30:32,359
But there is another
even more radical possibility.
573
00:30:32,359 --> 00:30:37,531
What if there are fewer
dimensions than we think?
574
00:30:37,531 --> 00:30:42,269
What if there is less to reality
than there appears to be?
575
00:30:42,939 --> 00:30:46,776
We live in a world
of cause and effect.
576
00:30:46,776 --> 00:30:51,581
The universe appears to behave
in predictable ways.
577
00:30:51,581 --> 00:30:55,552
But down deep,
at the subatomic level,
578
00:30:55,552 --> 00:30:58,721
reality shifts and changes.
579
00:30:58,721 --> 00:31:02,291
The world we know gives way
to quantum strangeness,
580
00:31:02,291 --> 00:31:05,428
where all realities happen
at once,
581
00:31:05,429 --> 00:31:10,600
and the outcome of any event
is unknowable.
582
00:31:12,000 --> 00:31:16,438
Can an object be in two places
at once?
583
00:31:16,438 --> 00:31:19,942
Can things appear
out of thin air?
584
00:31:21,143 --> 00:31:24,713
Not in the reality we live in.
585
00:31:24,713 --> 00:31:27,982
But nature has many layers.
586
00:31:27,983 --> 00:31:29,985
And the closer we look,
587
00:31:29,985 --> 00:31:35,057
the more we find reality
as we know it breaks down
588
00:31:35,057 --> 00:31:38,727
and magic is real.
589
00:31:40,000 --> 00:31:43,037
Okay, guys.
An amazing sleight of hand.
590
00:31:43,037 --> 00:31:46,740
Just follow the coin,
guess the hand.
591
00:31:46,740 --> 00:31:48,242
You ready?
592
00:31:51,045 --> 00:31:52,813
Do this one again to see...
593
00:31:52,813 --> 00:31:56,350
Freeman: David tong is not
a professional magician.
594
00:31:56,350 --> 00:31:59,119
He's a theoretical physicist
595
00:31:59,119 --> 00:32:02,889
at Cambridge university centre
for mathematical sciences,
596
00:32:02,890 --> 00:32:05,793
where he studies
the magic of the quantum world.
597
00:32:05,793 --> 00:32:07,460
[ Coin drops ]
598
00:32:07,461 --> 00:32:08,495
[ Chuckles ]
599
00:32:08,495 --> 00:32:10,597
Okay, in my defense,
I could argue
600
00:32:10,597 --> 00:32:13,267
that this is just an example
of quantum uncertainty.
601
00:32:13,267 --> 00:32:14,735
For particles like electrons,
602
00:32:14,735 --> 00:32:16,469
you never know
where they're gonna be
603
00:32:16,470 --> 00:32:18,138
from one minute to the next.
604
00:32:18,138 --> 00:32:19,607
In fact,
605
00:32:19,607 --> 00:32:22,476
by the time you go down to the
fundamental level of reality,
606
00:32:22,476 --> 00:32:26,280
it looks like everything is
something of an illusion.
607
00:32:29,049 --> 00:32:33,587
Freeman:
In the subatomic world, at the
smallest known level of reality,
608
00:32:33,587 --> 00:32:37,691
particles like electrons don't
obey the laws of common sense.
609
00:32:37,691 --> 00:32:41,761
They obey the laws
of quantum mechanics.
610
00:32:41,761 --> 00:32:43,864
In the quantum world,
611
00:32:43,864 --> 00:32:46,700
the properties
that a particle seems to have
612
00:32:46,700 --> 00:32:48,936
depends
on the experiment you do.
613
00:32:48,936 --> 00:32:51,938
You can measure
the position of a particle
614
00:32:51,939 --> 00:32:54,441
with as much accuracy
as you like,
615
00:32:54,441 --> 00:32:57,177
or you can measure its speed,
616
00:32:57,177 --> 00:33:01,182
but you can't measure both
at the same time.
617
00:33:01,182 --> 00:33:07,187
Similarly, an electron can
appear as a particle or a wave,
618
00:33:07,187 --> 00:33:11,190
but never as both
at the same time.
619
00:33:11,191 --> 00:33:17,130
Quantum objects are fuzzy,
like the edges of shadows.
620
00:33:17,130 --> 00:33:21,267
It doesn't make sense, but this
really is the way nature works
621
00:33:21,268 --> 00:33:24,037
at the most fundamental level.
622
00:33:24,037 --> 00:33:27,140
Tong:
Quantum mechanics is simply
the best scientific theory
623
00:33:27,140 --> 00:33:28,542
that we've ever developed.
624
00:33:28,542 --> 00:33:31,511
It underpins everything we
understand about the universe.
625
00:33:31,511 --> 00:33:33,447
It's never been found
to be wrong.
626
00:33:33,447 --> 00:33:35,114
But where does this leave us?
627
00:33:35,115 --> 00:33:37,451
What is the true reality?
628
00:33:37,451 --> 00:33:40,821
Freeman: The prevailing theory
of quantum mechanics
629
00:33:40,821 --> 00:33:43,490
suggests we will never know
630
00:33:43,490 --> 00:33:45,659
because we can never measure
all of the properties
631
00:33:45,659 --> 00:33:48,928
of quantum objects
with absolute certainty.
632
00:33:48,929 --> 00:33:50,965
It's like the story
of Plato's cave.
633
00:33:51,064 --> 00:33:54,034
2,000 years ago, the Greek
philosopher Plato suggested
634
00:33:54,035 --> 00:33:57,238
that we could never understand
the true meaning of reality.
635
00:33:57,238 --> 00:33:59,540
He said we were
a little like prisoners,
636
00:33:59,540 --> 00:34:02,108
chained in a cave and forced
to look at the back wall.
637
00:34:02,108 --> 00:34:03,510
Behind the prisoners,
638
00:34:03,510 --> 00:34:06,345
there is a distant fire
which throws shadows over them,
639
00:34:06,345 --> 00:34:08,948
shadows of the life that's
going on behind the prisoners.
640
00:34:08,948 --> 00:34:11,318
But they never get to see
that life.
641
00:34:11,318 --> 00:34:13,120
All they see are the shadows.
642
00:34:13,120 --> 00:34:14,521
And after a while,
643
00:34:14,521 --> 00:34:17,823
they think reality is some
two-dimensional dancing image.
644
00:34:17,823 --> 00:34:19,860
They've got no way
of ever turning around
645
00:34:19,860 --> 00:34:22,062
and seeing this beautiful,
colorful three-dimensional world
646
00:34:22,062 --> 00:34:23,296
behind them.
647
00:34:23,296 --> 00:34:25,832
Now, this is a little bit
like quantum mechanics.
648
00:34:25,832 --> 00:34:27,601
We can never understand
everything
649
00:34:27,700 --> 00:34:28,936
about the quantum wave.
650
00:34:28,936 --> 00:34:30,704
We can never measure
all of the information
651
00:34:30,704 --> 00:34:32,539
which is contained in it.
652
00:34:32,539 --> 00:34:34,642
All we can see are projections,
653
00:34:34,642 --> 00:34:37,244
like the shadows
of the true reality.
654
00:34:37,343 --> 00:34:41,849
Freeman:
But David says the truth may be
even stranger than that.
655
00:34:41,849 --> 00:34:46,721
The shadows on the wall may be
the true reality.
656
00:34:48,154 --> 00:34:51,659
This is the contention
of the holographic principle.
657
00:34:51,659 --> 00:34:54,295
Mathematicians attempted
to calculate
658
00:34:54,295 --> 00:34:58,065
the amount of information
you can cram into a black hole.
659
00:34:58,065 --> 00:35:01,101
They realized
the amount is proportional
660
00:35:01,101 --> 00:35:04,438
to its surface area,
not to its volume.
661
00:35:04,438 --> 00:35:06,773
And if this is true
for a black hole,
662
00:35:06,774 --> 00:35:11,778
they reasoned, it's probably
true for any region in space.
663
00:35:11,778 --> 00:35:14,514
Right now, we could all be
inside a huge black hole
664
00:35:14,514 --> 00:35:15,683
and not even know it.
665
00:35:15,683 --> 00:35:21,621
Reality may actually be
two-dimensional.
666
00:35:21,622 --> 00:35:25,693
Think of everything in the
universe as bits of information,
667
00:35:25,693 --> 00:35:29,463
like the information stored
in the books on this wall.
668
00:35:29,463 --> 00:35:31,198
When the books lie flat
like this,
669
00:35:31,198 --> 00:35:33,100
they appear two-dimensional.
670
00:35:33,100 --> 00:35:35,335
But, of course,
when I pull them out,
671
00:35:35,335 --> 00:35:38,304
we see that the books are
three-dimensional at heart.
672
00:35:38,305 --> 00:35:40,541
The information is
three-dimensional.
673
00:35:40,541 --> 00:35:44,211
The holographic principle says
that this is an illusion
674
00:35:44,211 --> 00:35:47,581
not just this, but you, me,
the earth, the stars,
675
00:35:47,581 --> 00:35:49,048
even space itself
676
00:35:49,049 --> 00:35:51,051
everything
that's three-dimensional
677
00:35:51,051 --> 00:35:53,553
is actually an illusion.
678
00:35:53,553 --> 00:35:56,690
The true reality is
the books lining the wall.
679
00:35:56,690 --> 00:36:00,027
The true reality lives
in two dimensions.
680
00:36:00,027 --> 00:36:04,130
Freeman:
And this explains why quantum
objects look fuzzy to us.
681
00:36:04,131 --> 00:36:05,465
They are projections
682
00:36:05,465 --> 00:36:09,737
that don't actually exist
in three-dimensional space.
683
00:36:09,737 --> 00:36:12,472
Tong: And what we think of
as this three-dimensional world
684
00:36:12,473 --> 00:36:14,341
is just a holographic projection
685
00:36:14,341 --> 00:36:16,777
from a surface
somewhere in the universe
686
00:36:16,777 --> 00:36:18,211
to create the space we see.
687
00:36:18,211 --> 00:36:21,981
It's as if Plato's prisoners
had it right all along.
688
00:36:21,981 --> 00:36:23,584
The shadows are real.
689
00:36:23,584 --> 00:36:26,386
What's behind them was
the illusion.
690
00:36:26,386 --> 00:36:29,089
Freeman: Right now,
there is no way to prove
691
00:36:29,089 --> 00:36:30,891
whether
the holographic principle
692
00:36:30,891 --> 00:36:33,559
is the genuine description
of reality
693
00:36:33,560 --> 00:36:37,331
or the shared delusion
of theoretical physicists.
694
00:36:37,331 --> 00:36:39,933
But there may be
another explanation
695
00:36:39,933 --> 00:36:41,802
for quantum weirdness.
696
00:36:41,802 --> 00:36:44,771
What if reality gets blurry
697
00:36:44,771 --> 00:36:47,641
because it was never there
to begin with?
698
00:36:47,641 --> 00:36:49,476
Some scientists say
699
00:36:49,476 --> 00:36:54,414
our reality could be
a deliberately created illusion.
700
00:36:58,000 --> 00:37:00,335
Using the tools of science,
701
00:37:00,335 --> 00:37:04,739
we catch glimpses of
the vast structure of creation.
702
00:37:04,739 --> 00:37:08,409
There is so much we cannot see.
703
00:37:08,410 --> 00:37:12,714
Why is the truth
so hard to find?
704
00:37:12,714 --> 00:37:17,019
Perhaps it's because
the universe we live in
705
00:37:17,019 --> 00:37:21,256
is just a small part
of a larger reality...
706
00:37:21,256 --> 00:37:28,430
And we are all just living
in a world of dreams.
707
00:37:30,632 --> 00:37:35,670
[ Alarm blaring ]
708
00:37:35,670 --> 00:37:36,704
[ Alarm beeps, blaring stops ]
709
00:37:36,705 --> 00:37:39,641
Have you ever had
a recursive dream...
710
00:37:39,641 --> 00:37:40,809
[ Alarm blaring ]
711
00:37:40,809 --> 00:37:41,943
[ Alarm beeps, blaring stops ]
712
00:37:41,943 --> 00:37:45,213
...a dream with a dream
within a dream?
713
00:37:45,213 --> 00:37:48,650
[ Alarm blaring ]
714
00:37:48,650 --> 00:37:49,985
[ Alarm beeps, blaring stops ]
715
00:37:49,985 --> 00:37:53,822
Jan westerhoff has.
716
00:37:53,822 --> 00:37:57,224
And for all he knows,
he might still be dreaming.
717
00:37:57,225 --> 00:38:00,562
Or you might be dreaming this.
718
00:38:00,562 --> 00:38:03,832
Westerhoff: How do you know
whether waking up this morning
719
00:38:03,832 --> 00:38:05,233
was actually a real awakening?
720
00:38:05,233 --> 00:38:09,004
Perhaps you just woke up
into another dream.
721
00:38:09,004 --> 00:38:11,073
The reason why
you should worry about this
722
00:38:11,073 --> 00:38:13,308
is that there is actually
a significant chance
723
00:38:13,308 --> 00:38:15,476
that we are dreaming right now.
724
00:38:15,476 --> 00:38:17,378
Let's do the numbers.
725
00:38:17,379 --> 00:38:19,615
Freeman: According to jan,
726
00:38:19,615 --> 00:38:24,720
most people spend 8 hours asleep
and 16 hours awake every day.
727
00:38:24,720 --> 00:38:29,057
About 20% of sleep is spent
in the r.E.M. State,
728
00:38:29,057 --> 00:38:30,558
when you dream.
729
00:38:30,558 --> 00:38:35,029
20% of 8 is 1.6, which means...
730
00:38:35,029 --> 00:38:37,566
Westerhoff: We know
that, at this very moment,
731
00:38:37,566 --> 00:38:40,402
you have a 1 in 10 chance
of dreaming right now,
732
00:38:40,402 --> 00:38:43,304
which is actually
quite a significant probability.
733
00:38:47,142 --> 00:38:50,612
Freeman:
Jan doesn't actually believe
he lives in a dreamworld,
734
00:38:50,612 --> 00:38:54,615
but as a philosopher at the
university of durham in england,
735
00:38:54,616 --> 00:39:00,055
his job is to question how and
why things are the way they are.
736
00:39:00,055 --> 00:39:03,525
And despite
what the numbers say,
737
00:39:03,525 --> 00:39:08,863
logic tells you
you are probably not asleep.
738
00:39:08,863 --> 00:39:10,365
If this was a dreamworld,
739
00:39:10,365 --> 00:39:13,133
why would it be bound
by the laws of causality?
740
00:39:13,134 --> 00:39:16,571
Why don't fire-breathing dragons
go rampaging through London,
741
00:39:16,571 --> 00:39:18,841
destroying the city?
742
00:39:22,677 --> 00:39:24,379
Well, they don't.
743
00:39:24,379 --> 00:39:26,715
What you saw was
just an illusion.
744
00:39:26,715 --> 00:39:28,682
Reality follows
a strict set of rules,
745
00:39:28,683 --> 00:39:31,486
even though it gets a little
blurry at the quantum level.
746
00:39:31,486 --> 00:39:32,821
What might explain that?
747
00:39:32,821 --> 00:39:35,223
Well, perhaps we are living
in a simulation
748
00:39:35,223 --> 00:39:37,326
made by a higher-order reality.
749
00:39:38,794 --> 00:39:41,863
Freeman: In other words,
reality may not be a dream,
750
00:39:41,863 --> 00:39:44,233
but it could be
a computer simulation.
751
00:39:46,334 --> 00:39:49,437
Imagine a time,
perhaps centuries from now,
752
00:39:49,437 --> 00:39:51,272
when our descendants have
the power
753
00:39:51,272 --> 00:39:55,610
to model fully functional
human brains in computers.
754
00:39:55,610 --> 00:39:58,079
These simulated minds
could be placed
755
00:39:58,079 --> 00:40:00,248
in computer-simulated worlds,
756
00:40:00,248 --> 00:40:03,284
perhaps even re-creations
of the past.
757
00:40:03,284 --> 00:40:06,421
They would never know
they weren't real.
758
00:40:06,421 --> 00:40:09,458
What if this
has already happened?
759
00:40:09,458 --> 00:40:14,295
Westerhoff: How do we know that
the present year we are in here
760
00:40:14,295 --> 00:40:18,633
is actually the original
rather than some sort of rerun
761
00:40:18,633 --> 00:40:22,337
where some weird event
in the past had been changed
762
00:40:22,337 --> 00:40:25,707
just to see what kind
of ramifications it had?
763
00:40:29,411 --> 00:40:32,079
Freeman: Believe it or not,
764
00:40:32,080 --> 00:40:37,452
there is a chance we are all
part of a giant simulation.
765
00:40:37,452 --> 00:40:40,488
Imagine, for example,
that I buy a dalí print.
766
00:40:40,488 --> 00:40:42,491
I get really excited about this
767
00:40:42,491 --> 00:40:45,093
because I just love
melting clocks.
768
00:40:45,093 --> 00:40:48,229
Now the problem here is
that, according to experts,
769
00:40:48,229 --> 00:40:51,600
about 90% of all dalí prints
on the market are fake.
770
00:40:51,600 --> 00:40:55,837
So the chance that I've got
a fake here is 0.9.
771
00:40:55,837 --> 00:40:57,171
Huh?
772
00:40:57,171 --> 00:41:00,508
Freeman: What are the odds
that our world is a fake?
773
00:41:00,508 --> 00:41:01,677
Huh?
774
00:41:00,508 --> 00:41:01,677
Huh?
775
00:41:01,677 --> 00:41:04,713
Some say as high as 1 in 20.
776
00:41:04,713 --> 00:41:08,150
But jan says
the percentage isn't important.
777
00:41:08,150 --> 00:41:12,186
If there is any chance at all
that you are simulated,
778
00:41:12,187 --> 00:41:15,223
then you can't dismiss
the possibility
779
00:41:15,223 --> 00:41:18,193
that you are simulated.
780
00:41:18,193 --> 00:41:19,761
But here is the thing
781
00:41:19,761 --> 00:41:23,030
even if this is all a dream,
does it really matter?
782
00:41:23,030 --> 00:41:24,867
Even if this is
just a dream cake
783
00:41:24,867 --> 00:41:30,105
and I paid for it with dream
money, it still tastes great.
784
00:41:30,105 --> 00:41:33,441
So presupposing
this all continues,
785
00:41:33,441 --> 00:41:36,578
does it really matter whether
it's a dream or a simulation?
786
00:41:36,578 --> 00:41:39,581
I can still plan my life,
causes will have effects,
787
00:41:39,581 --> 00:41:43,085
and actions will have
consequences.
788
00:41:49,725 --> 00:41:53,828
Is reality real?
789
00:41:53,828 --> 00:41:57,165
It certainly seems real to us.
790
00:41:57,165 --> 00:41:59,968
But we now know
the reality we perceive
791
00:41:59,968 --> 00:42:03,505
is just a small slice
of what really is.
792
00:42:03,505 --> 00:42:07,809
And, perhaps, in the long run,
that doesn't matter.
793
00:42:07,809 --> 00:42:12,647
What matters most to us is
the reality we know.
794
00:42:12,647 --> 00:42:15,650
As the philosopher-king
Marcus aurelius wrote
795
00:42:15,650 --> 00:42:21,422
2,000 years ago,
"The universe is change.
796
00:42:21,422 --> 00:42:25,927
Our life is
what our thoughts make it."
63865
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