A mad scientist has captured your friend
and implanted some kind of brain control
device. She enters commands into a machine
and your friend has no choice but to
follow them. Most of us would say that he
doesn't have free will
as someone else is now controlling all
his actions. But what if the scientist
got a bit lazy and decided to put the
machine on autopilot and have a set of
roulette wheels decide his behavior? With
this addition of randomness does he now
have free will? Most of us would
still say no.  Author Sam Harris in
his book The Moral Landscape argues that
this is the state we're all in now, and that
instead of roulette wheels our actions
are decided by the unpredictable desires
of our unconscious brains. But physics
has a different argument against
free will and it's the idea of
determinism. That events in the future are
caused by events in the past. If we
follow that logic all the way back to
the beginning of the universe it's
reasonable to say that everything that's
happened from the Big Bang up until now
is a chain of events resulting from the
way things were in our early universe.
That specific arrangement of gas and
molecules led to the formation of the
planets, which led to the creation of life,
which led to the evolution of man, which
eventually led to you watching this
video. This idea is called the Newtonian
clockwork universe and it's what
Einstein meant in his famous words "God
does not play dice". From a completely
Newtonian point of view we have every
reason to believe that we live in a
predetermined universe. That what you had
for breakfast this morning was already
decided billions of years ago in the
arrangement of molecules. But if that's
true then why do we have such a hard
time predicting the future? We know all
of the equations that describe the
behavior of the largest planets to the
tiniest atoms, so why don't we know if it
will rain a week from now?
Well let me tell you a story about an
American meteorologist named Edward
Lorenz. One day he was using an LED
desktop computer to model weather patterns.
After running a simulation he wanted to
repeat it so he put the same numbers
into the computer, but to his surprise
the outcome was totally different. Why? In
the first simulation Lorenz had entered
his numbers to six decimal places but in
the repeat the computer rounded it off
to just three. Lorenz had expected that a
difference as small as 0.000127
would it have much impact, but it did. It
changed the weather pattern in a totally
unrecognizable and unpredictable way.
This is commonly known as the butterfly
effect. The idea that a butterfly
flapping its wings can cause a tornado
on the other side of the world. It's
important to note that the wind from the
butterfly isn't what causes the tornado,
but billions of tiny interactions in
between that may not have occurred if it
wasn't for that flap. This kind of behavior
is seen everywhere in nature from the
weather to the motion of galaxies, how
animal populations grow and decline and
the beating of our hearts. So we can see
that even tiny inaccuracies lead to huge
changes in even pretty simple systems.
The unexpected relationship between
determinism and predictability is called
chaos theory and it highlights how
perfectly logical steps can lead to
seemingly random behavior that isn't
really random at all. So does this mean
the universe isn't determined? Well no, if
we played it back and started in the
same conditions it would play out the
same every time. It just means that in
practice we would never be able to
measure anything to 100% precision so
the final outcome of even simple systems
remains a mystery
to us. Okay so we can't predict things
because it's physically impossible to get
all the information, but what if it
weren't? What if in the future a
supercomputer was built that could know
the exact position and state of motion
of all the atoms in the universe to
100% precision? You have this computer
and you find out some people you know
are going to a movie tomorrow night.
You're not really in with this group so
aren't sure if you'll be invited. You ask
the computer
"Will Dana and her friends invite me to
the movies tomorrow?" It measures all the
particles in the universe, including the
neurons in Dana's brain and says yes! But
you get a bit overexcited and start
acting weird which ends with Dana not
inviting you to the movies. But if the
computer had said no you would have been
a bit disappointed but it's gotten over
it and gone off to do your own thing.
This cool attitude would have led to
Dana inviting you to the movies after
all.
So the supercomputer can't give you an
answer without changing your behavior.
Basically because it's interacting with
the universe it has an impact on it so
it can make correct predictions, it just
can't tell you about them without
changing them. So what does this mean for
free will? If the unfolding of the
universe is predetermined all the way
back from the Big Bang, does that mean we
have no say in our fate and all the
actions and thoughts we're going to have
have already been decided by gas clouds
and molecules billions of years ago?
Einstein thought so. After all, the brain
is also made of atoms following the same
laws of physics. But others believe that
we do have free will thanks to quantum
physics. Uncertainty and randomness seem
built into the behavior of quantum
particles. The quantum world is very
different to our daily world and the
equations that govern pool balls and
planets are totally useless there. But as
with the mad scientist and roulette
machine, does this randomness really
equal free will? Others think, sure, it
may 
save us from a deterministic universe,
but the fact that we have no control
over this randomness means we have just
as little control over our actions and
choices. But legendary theoretical
physicist Stephen Hawking holds a
different view. That free will is saved not
by quantum mechanics but by chaos theory.
If the laws of physics really do govern
all our actions they do so in a way
that's impossible to calculate,
especially for an organism as complex as
the human.  What gives us free will is
our inability to predict what we'll do
next, so the choices we make are, to us,
real choices. Which of these points of
view you subscribe to? You're free to
agree or disagree with any of them in
the comments below, or are you?
