- Try something for me.
Point to where you are.
Point to where you think your consciousness is,
where you're experiencing the world from.
You're probably all now
pointing somewhere around your head, right?
We all feel like we are somewhere behind our eyes,
but we know that all that's in there is your brain
and not some secret compartment that holds all your
thoughts and fears and desires.
What I'm trying to say is
that it's hard to measure where you are
compared to where you feel you are.
But what if we downloaded you into a machine body?
Then, we might be able to measure you
in a different way.
In 1995, the seminal anime film, Ghost in the Shell,
posited a world so technologically advanced,
that most, if not all, of the human body became obsolete.
Entire bodies and brains could be synthesized
and only a person's ghost or consciousness
needed to be transferred into it.
Technology powered consciousness transfer
is an interesting philosophical and political
and ethical thought experiment,
but what would actually transfer to a shell?
If I somehow transferred my consciousness
into this synthetic brain,
would this brain change in some way?
Would what I consider immaterial become material?
What would my ghost weigh?
In the early 20th century, a physician named
Duncan MacDougall famously reported
that immediately after death,
one of his patients weighed 21 grams less.
And for over 100 years, this figure has been used by people
as the weight of your ghost or your soul,
what many people consider to be you.
MacDougall's experiments were never considered scientific,
so now that consciousness transfer
isn't a completely out of bounds idea,
I think we can replace this figure
with something a lot more grounded.
If you are consciousness, as I would argue,
then if someone wanted to transfer your ghost
into a shell, they would first have to translate
all of the information that is in your brain into data,
if that's even possible,
but estimates for how much data your brain holds
range anymore from one terabyte to one petabyte.
And the high end estimate, one petabyte,
is like stacking 39,000 64 gig flash drives
250 meters high.
We don't understand consciousness yet,
so thinking of it as just simple data points and connections
probably isn't right.
But it's a start
and a way to weigh your ghost.
If we wanted to store the state of your brain right now,
then using flash memory, like is used in solid state drives,
wouldn't be a bad idea
because even if your shell's power turned off,
the state of your ghost would remain.
The physics of flash memory is pretty complicated,
but these are the basics.
This is your basic flash memory unit.
It's a transistor with what's called
a floating gate right here.
Right now, when there's no charge,
your computer would register this setup in binary as a one,
but if you start applying charge to it at the worldline
and what's called the bitline,
electrons are compelled to flow
through even this non-conductive material
that separates them.
However, as they do that, electrons begin to quantum tunnel
and build up at the floating gate,
acting to prevent charge from flowing to the worldline.
Once the flow of electrons is blocked by the floating gate
by more than 50%,
most of the flow is going between the source
and the drain here and your device reads it as a zero
in binary and that's how you get both bits.
But if you reverse the flow at the worldline
and the bitline, then all of the gates are cleared
and effectively erases the data.
According to quantum mechanics,
when electrons are trapped in the floating gate,
when data is being written,
they have more energy compared to when they are not trapped.
This is what would give your ghost mass.
Back in 2011, Professor John Kubiatowicz at UC Berkeley
estimated that the energy increase of trapped electrons
per bit was one one thousand trillionth of a joule.
And although the total number of electrons in the system
isn't changing, when some electrons have more energy,
there is technically more mass,
thanks to mass-energy equivalence,
in a full solid state drive.
So, mass-energy equivalence from Einstein's
E equals m c squared can estimate the mass increase
in a fully loaded synthetic brain
with maybe on average half zeros and half ones for data.
Using the high end estimate of 2.5 petabytes,
the mass of your consciousness would be
just 100 femtograms.
If you're not familiar with that number,
that's a million times less massive
than a grain of fine sand.
Almost nothing.
We think of ourselves as heavy fleshy things,
but transfer everything that could be considered you
into a Ghost in the Shell style body,
and that download wouldn't change any scale
we've ever developed.
Using this estimate, the consciousness of
every single human being on Earth
would weigh less than a single snowflake.
Your digital ghost wouldn't weigh anywhere near 21 grams,
but it would be something,
as close as you could get to a physical essence.
So, how much would a shell's ghost weigh?
Well, according to mass-energy equivalence
and using something like a solid state drive,
just one ten trillionth of a gram,
just the energy of electrons
encoding the thunderstorms of brain activity
inside of a collection of molecules
resisting entropy futilely.
It sounds even more dystopian than Ghost in the Shell,
doesn't it?
Don't worry.
Even if in the future, you are just ones and zeros,
only you will arise from a unique
and awesome arrangement of them.
Because Science.
Thank you so much for watching.
Make sure to follow me on Twitter at Sci_Phile
where you can suggest ideas for future episodes
and on Instagram under the same handle
where I'm now posting mini-episodes.
And a big shout-out to YouTubers like Vsauce
who have also calculated the weight of data before.
It was very helpful,
and as always, thanks for watching.
In the 1995 movie, the Major rips her own arms off
on top of a tank trying to open the tank.
And she could, if she had a synthetic body,
she could totally do that.
If her hands just had a ton of grip
and maybe she could lock them like an eagle's talons do
with tendons on their bones,
which is super badass but beside the point,
then she could lock her hands onto the tank
and then apply so much superhuman robot strength
to her joints that she would rip her own arms off
although at some point while they were ripping,
they would probably give out,
so maybe it wouldn't rip all the way
unless you applied it super forcefully.
So, Ghost in the Shell, completely scientifically accurate.