Freeman: What happens when we die?
Do we simply cease to be?
Or do we survive in some form?
What is it that makes us unique, conscious beings?
It's the greatest mystery of existence,
a problem seemingly too big for science to solve.
But today, a cluster of biologists,
physicists, and philosophers
are closing in on the answer to the ultimate question.
Is there life after death?
Space, time, life itself.
The secrets of the cosmos lie Through the Wormhole.
Is death the end?
Eternal silence?
Blackness?
Nothingness?
Or is there a spark inside of us
that lives on beyond our physical selves?
Philosophers and scientists have puzzled over that question
for thousands of years.
It's the great mystery -
one that, sooner or later, we all have to face.
One morning when I was 6 years old,
my grandmother didn't wake up -
then or ever again.
It was my first experience with death.
How could she be here yesterday but gone today?
Was she gone forever?
Or did some essential part of her live on?
Christians and Muslims believe in a heaven for the just
and a hell for sinners.
Other religions see death as a transition
to an existence on the higher plane
or to another life here on Earth.
All of these beliefs have one thing in common -
the body is just a vessel for the soul,
and the soul is eternal.
This is something many believe in their hearts,
but is there a way to prove it or disprove it scientifically?
Eben Alexander taught and performed neurosurgery
at the Harvard Medical School for 15 years.
In 2008, his career took an unexpected turn -
one that would give him profound insight
into the possibility of life after death.
He contracted an extremely rare form of bacterial meningitis
and fell into a deep coma.
I think if you were trying to come up
with an experimental model
that would best approach human death,
meningitis is perfect because what it does
is it attacks the entire outer surface of the brain.
These are horizontal images taken through my skull,
and you can see the entire outer surface of the brain
was coated with pus.
These bacteria had gotten rid of all the glucose,
and now the only thing left to consumer were my brain cells,
and so my entire neocortex -
that part of the brain that makes us human -
was completely shut down.
Freeman: After seven days of virtual brain death,
Alexander emerged from the coma.
Miraculously, within a month, he was back to normal.
But something happened to him while he was away.
My first recollection from deep inside the coma
was that I was -
it's what I sometimes call the earthworm-eye view of the world.
Everything was kind of murky, brown, red, dark.
I literally remember roots over my head.
And I seemed to be there for a very, very long time.
I had no memory whatsoever of my life.
No words - my language was gone.
I was certainly not aware of anything going on around me
in the ICU room.
And then, in the midst of that,
there was a little melody that was spinning in front of me.
And it just started spinning and expanded,
and it ended up clearing away
all that ugly, foreboding, gross, muddy realm.
And all of a sudden,
I was coming up into this beautiful meadow.
I had no body awareness.
I had no arms, legs, or anything,
but I was aware that I was a speck on a butterfly wing -
absolutely beautiful butterfly.
And there were millions of other colorful butterflies
looping and swirling all around us,
all in this beautiful formation of flying.
And then we left this universe
and went out into what I now call the core.
At first, it seemed infinitely huge and dark,
although I was there
with that beautiful, warm awareness of the divine,
which was clearly what we would call God
in this place outside the universe.
Basically, I recall the whole multiverse
being out in front of me.
It was very clear that love was a huge part
of the constituent of that whole multiverse.
Freeman: Alexander had faced something
that tens of thousands of people have reported -
a near-death experience.
Nearly all claim something
that science has so far been unable to prove -
that there is another existence beyond the one we know.
Dr. Alexander: This was something
that was very difficult for me to explain
from a neuroscientific standpoint,
and the scientific side of me could not see how that could be,
and yet it was a very, very powerful -
very powerful memory.
I came up with several models having to do
with the neurophysiology and neuroanatomy.
And the problem is none of those models sufficiently explain
the very powerful memories that I brought back with me
from this experience.
And I ended up at a point where I do not believe
that there is a good neurophysiologic explanation
for what happened to me.
Freeman: Eben Alexander's experience
was profound and life-altering.
But it is by no means unique.
Bruce Greyson is a psychiatrist
at the University of Virginia School of Medicine.
He has investigated more than 1,000 cases
of near-death experiences.
The consistent features of a near-death experience
are a sense of profound peace and well-being,
a sense of leaving the physical body,
a sense of brilliant light
which seems to radiate warmth and unconditional love.
Sometimes people report encountering other beings,
including a deity of some kind.
Sometimes they identify that deity as God or Christ,
and sometimes they don't.
They just say that there was
this all-powerful being that they met.
Freeman: Many scientists dismiss these experiences
as nothing more than hallucinations
triggered by a brain undergoing immense physical stress,
mostly due to the nerve cells being deprived of oxygen.
Back in the 1970s,
experiments by the U.S. Air Force
inadvertently tested this idea.
Scientists spun pilots in a centrifuge,
subjecting their bodies to massive G-forces.
It caused blood to drain to their feet
and left their brains starved for oxygen.
They invariably blacked out.
When they awoke, some pilots reported seeing a bright light.
Others said they left their bodies
and looked down at themselves from above -
experiences similar to those of people
who have been to the brink of death,
but lacking one key feature.
In the period when they were losing oxygen,
as they were losing consciousness,
they had some features
which bear some similarities to near-death experiences.
However, they certainly didn't ever meet deceased loved ones
or other entities.
The problem with all of these physiological explanations
is that they don't account for the complex thinking,
the memory formation, the perceptions that take place
when we know the brain
is not capable of doing complex thinking.
Freeman: Are near-death experiences
the final dream of a mind that's about to wink out of existence?
Or are they a sign that there is something beyond death?
Finding the truth requires nothing less
than a scientific quest to discover the human soul.
Is the soul a myth
or one of the fundamental elements of the universe?
For scientists, the question of life after death
is inextricably linked with another question.
What is consciousness?
Where does consciousness come from?
And where does it go when we die?
Dr. Stuart Hameroff is the Director
of Consciousness Studies at the University of Arizona, Tucson.
He's also a practicing anesthesiologist.
Under anesthesia, patients don't dream -
even though I said, "pick out a nice dream."
We always say that. But there's no awareness.
There's no passage of time. Patients wake up.
They don't know if they've been asleep five minutes or five hours.
Anesthesia takes away consciousness.
Brain under anesthesia is quite active.
And the difference is still somewhat mysterious.
Freeman: Years watching over patients in the operating room
made Hameroff obsessed with understanding the link
between brain activity and consciousness.
Then, 15 years ago,
he met the great British physicist, Sir Roger Penrose.
Together, they developed a radical new theory
for how the brain works -
a theory that has grown into nothing less
than a scientific argument for an eternal soul.
At its root are tiny structures inside our brain cells
called microtubules.
Dr. Hameroff: If you look inside a cell,
you find these structural components
that are somewhat like the bones within our bodies.
The microtubules develop literally a forest
inside each cell,
which determines the architecture
and the structure of the cell.
And we think microtubules are perfectly designed
to be the cell's onboard computer
and process information at the molecular level.
Freeman: Hameroff and Penrose argue that microtubules
allow neurons and the brain as a whole
to function as a quantum computer,
performing operations in a fundamentally different way
from normal computers.
Dr. Hameroff: So, here we have a brain with two hemispheres.
Most views of the brain
are of a collection of individual neurons.
When one neuron fires,
it sends a signal to the next neuron at a synapse.
That, in turn, causes that neuron to fire,
and that neuron causes another neuron to fire,
much like dominoes.
So, for example, if a neuron fires here,
it's gonna trigger its neighbors to fire,
sending signals through and around the brain.
That's the classical view of how the brain works.
Freeman: In a conventional computer,
signals move around from place to place
along traceable paths.
But the microscopic components of a quantum computer
are connected via a mysterious process called entanglement.
Some of us think that quantum processes
play an important role in consciousness in the brain.
So, for example, if there's neuronal activity here,
it may be coupled through quantum non-locality
to processes over here.
These neurons are connected
even though they're spatially separated
so that activity here
instantaneously affects activity over here.
Freeman: Hameroff and Penrose argue
that a change in the microtubules in one brain cell
can affect microtubules in another.
But that's not all.
Quantum theory claims that every single point in space,
even empty space, can contain information.
In the very fine structure of the universe,
there is information, quantum information,
not unlike these dominoes,
so that we can have information up or down, here and here,
but they're connected
so that something that happens here
influences something here.
Freeman: This means the information in the microtubules
can connect and become entangled
with the universe outside the brain.
Dr. Hameroff: So, just like these two neurons may be entangled,
it's possible that the information of consciousness,
of the whole brain, is entangled
and can exist in the universe at large.
Freeman: According to Hameroff,
our souls are built from something
much more fundamental than neurons.
They are constructed from the very fabric of the universe.
Dr. Hameroff: I think that consciousness or its immediate precursor -
we'll call it proto-consciousness,
has been in the universe all along,
perhaps from the Big Bang.
Freeman: All of this recalls the Buddhist and Hindu belief
that consciousness is an integral part of the universe,
and perhaps it is all there is in the universe.
If consciousness is a quantum process,
it may solve the mystery of what happens
during near-death experiences.
Dr. Hameroff: Let's say the heart stops beating,
the blood stops flowing,
the microtubules lose their quantum state.
But the quantum information, which is in the microtubules,
isn't destroyed.
It can't be destroyed.
It just distributes and dissipates
to the universe at large.
If the patient is resuscitated, revived,
this quantum information can go back into the microtubules,
and the patient says, "I had a near-death experience.
I saw white light. I saw a tunnel.
I saw my dead relatives.
I maybe even floated out of my body."
Now, if they're not revived and the patient dies,
then it's possible that this quantum information
can exist outside the body, perhaps indefinitely as a soul.
Freeman: Many scientists find it difficult to believe
that the soul is a quantum computer,
hard-wired into the cosmos.
But Hameroff feels that research is slowly validating his claims.
Quantum effects have recently been shown
to control several important biological processes,
from bird navigation to photosynthesis
to the human sense of smell.
Dr. Hameroff: So far, nobody has landed a serious blow to the theory.
We're still very viable, and evidence continues -
new evidence continues to support the ideas
that we put forth 15 years ago.
Freeman: But the truth is
we still don't know where consciousness comes from
or where it goes when we die.
If there was a way to measure consciousness,
perhaps we could find the answers to these questions.
That way may be coming soon,
as one scientist explores the depths of our minds,
hoping to discover the mysterious mental pattern
that makes us who we are.
The human brain isn't very big -
3 pounds of soft tissue.
But it can generate ideas that transform the world.
It can hold personalities as diverse
as Martin Luther King and Genghis Khan.
It even knows what it is.
It's self-aware.
We think it has a soul.
But where does that soul come from?
Is consciousness a product of the brain?
And can it outlive the brain?
Studying what happens to the human brain when people die
is not easy.
Death rarely comes on cue.
But one aspect of death comes to all of us every day.
Each night when we fall asleep, our consciousness slips away.
Professor Giulio Tononi of the University of Wisconsin
is studying how our brains change
when they lose consciousness,
and in doing so,
he's hoping to unravel the secret of what makes us us.
The simplest definition of consciousness -
that which goes away when you fall into dreamless sleep.
But the fact of the matter is,
the brain doesn't shut off at all.
The neurons, the nerve cells, are actually just as active,
in a sense, as they are when you are awake.
So, it is an interesting scientific question.
How would it be, then, that you disappear
when your brain is still there and buzzing along?
Freeman: Tononi believes our level of awareness
is determined by how much information
the different parts of our brain share with each other.
An experience rich in detail
will generate highly complex patterns in the brain,
creating unique shapes that Tononi believes can be measured.
Every experience is essentially like an extraordinary shape.
Just like a fire with wonderful flames
is an extraordinary shape that changes all the time.
Now, it's a shape which is characterized
by something I would call informational relationships.
But it's a shape that shines of inner light.
The fire of consciousness is a very special fire
that's generated inside the brain,
and it requires a very special set of ingredients
in order to be able to burn and shine.
Freeman: But understanding when that fire is lit
and when it is extinguished
is far more difficult than simply reading a brain scan.
So Giulio Tononi built an entire lab
dedicated to the unconscious netherworld of dreamless sleep.
And he designed an experiment to detect how the brain changes
when we lose consciousness.
It's the neurological equivalent
of knocking at the door of a darkened house
to find out whether anyone is home.
Tononi: We use something called
transcranium magnetic stimulation,
which is a way to inject a little current in the brain
without having to open it up,
so in a perfectly innocuous way,
and then see how our cerebral cortex reacts to it.
Freeman: First, the team runs the experiment
on a volunteer who's awake.
A mesh of electrodes will keep track
of all activity in his brain.
Now a small magnetic coil is placed on his head.
At the flip of a switch, it delivers a pulse of magnetism
lasting a tenth of a second to his cerebral cortex.
The burst causes neurons in a small patch of the brain
to fire,
and they, in turn, send signals to other neurons,
making them fire, as well.
This complex pattern of neural activity
spreads out to cover about a third of the cortex
and lasts for almost 1/3 of a second.
The conscious brain reverberates like a ringing bell.
Someone is definitely home.
But what happens when he's unconscious?
Now that Brady is asleep,
we are going to ring the bell again
and see how his brain responds when - after falling asleep.
Freeman: Once again, the brain lights up.
But this time, there is no reverberation.
The ring of the bell dies
as quickly as the pulse of magnetism shuts off.
The sleeping brain may be active,
but it has lost the ability to share information
between one part of the brain and another.
Tononi believes this spreading of information
is the key ingredient of consciousness.
The waking brain keeps specialized areas
in constant conversation,
like a cabinet meeting
with the secretary of state, treasury, and defense
all deciding on a unified plan of action.
When the brain is asleep, the meeting adjourns.
The specialists leave, and nothing gets decided.
Why do you lose consciousness
when you are in deep sleep early in the night?
The specialists that normally do talk to each other
when you are awake - they stop doing so.
There is some mechanism that comes into place when you sleep
that makes the interaction
between the specialists difficult.
And, in the end,
it looks like they can't talk to each other anymore,
and not surprisingly, then, you lose consciousness.
You're not there anymore.
Freeman: Tononi's ability to tell the difference
between a brain that's conscious and one that's not
may soon find application in a medical setting,
assessing the level of awareness of coma patients.
Tononi: One of the first things you would want to know is,
is anybody home?
If that somebody is your wife or your son or your mother
and you see the eyes are open
and you don't know whether somebody's there,
maybe even suffering, how do you go about that?
Freeman: Giulio Tononi has found a way
to see consciousness in the human brain,
but exactly how it arises amid the complex web of neurons -
that remains a mystery at which he can only begin to guess.
Tononi: When one says that consciousness
requires a complex system to support it,
in some sense, that must be true.
But the Internet is certainly very complex.
Another example, you could also say
that a chess-playing program is very complex.
So there are many things that people intuitively call complex,
but only a few of them
seem to be able to give rise to consciousness.
So what you need is the right kind of complexity,
and only a few structures - as far as I can tell -
can do that, can pull out that extraordinary feat.
Our cortex, the cerebral cortex,
seems to be wired up almost ideally
to achieve exactly that.
Freeman: But is there a way to discover the root of consciousness?
And is this sense of self-awareness
the same as the soul?
This man thinks he's found the human soul
and knows what happens to it when we die.
What is the soul?
Is it a field of energy?
Is it something tangible?
Does it have weight?
In 1907, Dr. Duncan MacDougall determined
that the soul weighs about 3/4 of an ounce,
or 21 grams.
He determined this by weighing the bodies of dying TB patients.
But in the 100 years since then,
no one has been able to replicate his findings
because there doesn't seem to be anything to weigh.
Could there be some elusive substance that makes you you?
At the smallest levels of existence,
all matter is made of atoms.
Earth has been recycling atoms for billions of years.
Carbon moves from trees to oceans
to the cells in our bodies.
Even the atoms of dead people get reused.
This means that an atom in your thigh bone
might have been part of Cleopatra's lower lip.
And this recycling doesn't just happen at the atomic level.
You are constantly rebuilding yourself at the cellular level.
Your body produces 1 billion new cells every hour.
No matter how old you are,
most of you is no more than 10 years old.
Christof Koch is a Professor of Biology and Engineering
at CalTech.
He believes that what makes you you
has nothing to do with individual atoms or cells.
He believes that "you" emerges from the unique way
the cells in your brain are organized.
The brain is the most complex piece of matter
we know in the universe.
The human brain typically is on the order
of 100 billion nerve cells.
Each of those is a very complicated entity by itself.
It's more like a little computer,
interconnected to 10,000 to 100,000 other nerve cells.
Freeman: Separately, these neurons aren't conscious.
But when they interact with each other on a massive scale,
the result is a self-aware network.
We believe that consciousness emerges
out of the firing of millions or possibly billions of neurons.
So that's what my soul is.
That's what my feelings, my subjective feelings
of pain and pleasure and of yearning are.
Freeman: But if, as Koch believes,
who we are stems exclusively from this fragile
and ever-changing network of brain cells,
then there can be no eternal you.
Koch: We constantly change.
With each experience, we change a little bit.
With some experiences, we change more,
and with other experiences, we change less.
So, that sense, there's no constant.
And as we age, again, my mind - my body,
but also my personality and my mind changes.
So, that sense, there's no constant personality.
It's a changing construct of the brain and by the brain.
Freeman: This view of the brain is called materialism,
and Koch is its champion.
For materialists,
the soul is nothing more than a fleeting illusion,
an illusion that cannot outlive
the physical network from which it arises.
Once that electrical traffic ceases
because the brain itself doesn't work anymore
and the neurons stop firing,
then, also, the soul will cease to exist.
Freeman: But renowned cognitive scientist Douglas Hofstadter
is not so quick to dismiss the possibility of life after death.
He believes the soul does not disappear the moment we die.
Hofstadter: When I was a graduate student in physics,
I had a professor who I was very fond of
who was a religious person.
And he believed, to my shock and surprise and confusion,
that inside the brain,
there were certain kinds of particles
that we hadn't yet discovered
that gave rise to soul and consciousness.
Freeman: Hofstadter took a more scientific approach
to the brain.
He became a pioneer in modeling complex mental processes.
He thinks about how people think.
And what humans do best, in his opinion,
is make mental maps of the world around them.
The process of perceiving a world
gives rise to internal representations of everything.
You know, if I look at this pepper shaker,
I have an internal model of it.
And I don't need to look at it
because I've seen it so many times,
I have an internal model of it that is stable.
Freeman: All animals make mental maps.
The bigger the animal, the more complex the map.
A bee knows the position of the sun and its hive.
A manta ray learns to navigate
the convoluted web of ocean currents.
A baboon must keep track
of the troop's social pecking order.
Our maps are built
from a lifetime of objects and people we've encountered...
And one other crucial element.
Hofstadter: We incorporate not only the rest of the world,
but we incorporate our own understanding
of who we are and what we are,
which includes superficial, physical things
like the fact that we have two hands
and five fingers on each hand,
what kind of sense of humor we have,
whether we're good at throwing free-throws in basketball
or hook shots.
And we create a concept that reflects who we are.
Freeman: Hofstadter regards this map of the world
that also includes a map of the map-maker
as a mental feedback loop.
If you point a television camera at a television screen
and then the screen gets put onto itself,
et cetera, et cetera,
and you get a very complex visual pattern -
the system itself is perceiving itself.
To me, the soul is an emergent process,
an emergent entity that comes out of decades
of perception and feedback.
Freeman: But this view of consciousness
has a shocking implication.
If the soul is just a strange mental feedback loop,
then it should not be unique to humans.
Any sufficiently smart network should be able to experience it,
whatever it is made of.
Which is why this latter-day Frankenstein
is planning to build a soul.
What he learns could point the way to a life beyond death.
Religion tells us that our souls transcend the body.
These are just shells that we walk around in for a while.
Most scientists don't believe that.
They say that what we call the soul
is a self-aware network of brain connections
that evolved over millions of years.
If that's true,
then what would happen if we built a copy of the human brain?
Would it have a soul?
We're on the verge of finding out.
And if the mystery of the mind
is something we can crack computationally,
it would even give us an escape route from death.
Around the world, teams of researchers
are attempting to reverse-engineer a human brain.
It's a tough job, because for all our research,
the brain is still the most complicated instrument
in the known universe.
But mapping the brain could take decades to complete,
which is why some rebel scientists
have decided to harness the firepower
inside living brain cells.
They're trying to crack the secrets of the soul
by fusing biology and technology,
taking bits of brain and mating them to bits of hardware.
Most computer simulations
are limited to very simplistic neurons.
What we have here in our culture dishes
with real, live, wet, squishy neurons
with all their complexity,
is immensely much more complicated
than anything we can simulate on today's computers.
Freeman: Professor Steve Potter
of the Georgia Institute of Technology
designs and builds brains -
brains that are half-living, half-machine.
Potter's team takes neurons cultured from rat embryos
then grows them on miniature plates of electrodes.
Potter: Here is a multi-electrode array culture dish.
You can see some fluorescently labeled neurons growing on it.
These are the electrodes
with leads heading off to the electronics
that we use to record from and stimulate the cells.
These are all the axons and dendrites
that represent the connections between the cells.
Those connections form
over the course of the first four hours in culture.
You can see on this time lapse here
connections forming.
So, those are the synaptic connections
by which the neurons talk to each other,
and we can film that conversation in progress
using a calcium-sensitive dye here.
So, here you can see the cells flashing.
Every time the cell sends a signal to another cell,
it has a little burst of calcium.
Freeman: When the brain has grown,
potter send information to it through the electrodes,
and the brain responds.
Those electrodes are connected to a computer
that's wired up to a robot body,
resulting in a new form of life.
This is hybrot -
a robot controlled by living brain tissue.
Its brains are in a refrigerator,
but you can see its neurons react on the computer screen
as its body finds its way around the lab bench.
Like any animal,
the hybrot has experiences and learns from them.
In this case, how to navigate its environment.
So, the question is, could a hybrot ever become conscious?
Whether or not we could ever get to conscious cultured networks
is a question which I would say we've already answered "yes."
We have culture dishes
that are receiving inputs from the environment.
They're responding to them in complicated ways.
So they're conscious of their environment
in some very rudimentary fashion.
Perhaps with more complicated interactions
between different brain tissues
and between the computer and the brain tissues,
we could get to something that people would say
is a high-level cognition, more like human consciousness.
Freeman: But if one day a hybrot or a computer wakes up
and realizes what and who it is,
if a soul emerges from those wires,
how would we know?
We'll have to rely on conversation.
If we asked the artificial brain, "Are you conscious?"
And it persuades us that it is,
we'll just have to take its word.
But the same thing applies when we talk to other humans.
We don't actually know that other people are conscious.
They might just be zombies who are saying the right thing
but having no private, subjective experience.
I can put some sort of an artificial intelligence
into a computer right now
that represents the kind of decisions I might make
and has, in some sense, some of my consciousness in it.
So that's not hard to do.
But to get something that we would say
is a good enough copy of my consciousness
that if it were put back in somebody else's body,
people would be fooled into thinking it was me -
this is something we haven't even the first clue
of how to do it in any kind of a detailed way.
Freeman: Building artificial homes for our souls
may be a long time coming,
so what do we do in the meantime?
Turns out the ideal vessels
to carry souls after the death of the body
may already exist.
One could be sitting right next to you.
Despite our advanced technology,
the riddle of life still seems a long way from being solved -
Or... is it?
In Bloomington, Indiana,
Douglas Hofstadter says it's all a matter of perspective.
He believes consciousness is the inevitable result
of the strange and wonderful way
the brain joins information together
into patterns of thought.
And the patterns of thought that form us
are not unique to us.
We are all curious collages
of everyone we've ever been influenced by,
living or dead.
The pattern of your soul
is the strongest and most complex in your own brain,
but it can be passed on to other brains.
Hofstadter: This is a book of Chopin études.
These black splotches on white paper
capture some very, very central pieces
of Chopin's emotionality -
his highs, his lows,
his sense of triumph,
his sense of resignation or anguish.
Anything that was part of his emotional makeup comes through,
and one gets a very deep glimpse of another human being.
Perhaps 150, 160 years after that person
has officially vanished from the surface of the Earth,
something of their soul persists
and invades the minds and brains of millions of other people.
Freeman: This is a form of life after death
that we all experience,
though we may not recognize it for what it is.
Freeman: It took a great personal tragedy for Hofstadter to see this -
the death of his wife, Carol.
We were in Italy,
and it was a very sudden discovery of a brain tumor.
And we found out that she had a brain tumor
on the 11th of December,
and on the 12th of December, in the evening,
she fell into a coma.
So it was very, very, very fast.
When somebody that I have been entangled with
for so long and so deeply
is suddenly poofed out of existence,
I then had to, you know, confront the question
of what, if anything, survived
and where, if at all,
can a human soul be transplanted,
uprooted from one brain to another brain?
And my answer would have to be,
in a very limited sense, yes.
The degree to which Carol exists inside me -
it's a much stripped-down version of her.
It's a crude version. It's coarse-grained.
It's as if one had a mosaic done
in very, very small, fine stones -
a million of them.
And then it was a destroyed,
but somebody, before it was destroyed,
had made a copy of it but only using 1,000 stones.
And so the 1,000 stones
still have the same colors and the same kind of arrangement,
but much more coarse-grained, in a different medium,
in different stones.
The original has been destroyed,
but the copy exists in a coarse-grained version.
Freeman: And so, we live on.
A piece of our soul survives
in everyone we have ever encountered.
That soul fragment
is the strongest, most recognizable
in the people who loved us.
This form of life after death is one we can all relate to,
whatever our religion.
But is there some other resting place for the soul?
Does our consciousness just shimmer out of existence
in our last moments on Earth?
Is the soul nothing more than a network of neural processes,
something that one day can be recreated in a machine?
Or does the quantum state of our brain
get reabsorbed into the universe at large?
Scientists believe they are finally getting close
to solving this puzzle,
even though they passionately disagree about the answer.
When you lose consciousness, you lose your soul.
You lose everything.
The world does not exist anymore for you.
Your friends don't exist anymore.
You don't exist. Everything is lost.
If you take these near-death experiences at face value,
then they suggest that the mind or the consciousness
seems to function without the physical body.
Dr. Hameroff: I think the quantum approach
to consciousness can, in principle,
explain why we're here and what our purpose is
and also the possibility of life after death and reincarnation
and the persistence of consciousness
after our bodies give up.
Dr. Alexander: I have great belief and knowledge
that there is a wonderful existence
for our souls outside of this earthly realm,
and that is our true reality.
And we all find that out when we leave this earth.
Ultimately, every one of us will discover the truth.
But will we ever enter our final hour
knowing our fate?
Perhaps some things really are too big for humans to grasp.
That's when we have to shift from what we know
to what we believe.