Can science predict what you will do?

Does free will really exist?

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Episode Transcript

Speaker 1 (00:09):
Hey, jorgey, do you think science is good at predicting
the future. It doesn't do very well with predicting the weather,
does it well? Here in California just says sunny every day? Yeah?
I guess some states are easier to predict the better.
All right, but let me try my hand at it.
I have a prediction of the future. You're a psychic,
note and a physicist. Well, I predict that you cannot

(00:33):
go a whole episode without talking about bananas. What that's bananas? Boom,
there you go. I'm totally psychic. You know the difference
between a psychic and a physicist their salary where you
put the h That's the only difference. Hey, I'm RhE

(01:08):
and my cartoonist and the creator of PhD comments. Hi.
I'm Daniel. I'm a particle physicist, not a particle psychic,
and I'm a co author of our book We Have
No Idea, A Guide to the Unknown Universe. Welcome to
our podcast, Daniel and Jorge Explain the Universe, a production
of I Heart Radio, in which we talk about all
the amazing, the fascinating, the hot, the nasty, the wet,

(01:31):
the bright, the dirty, the soft, the quiet, the loud,
the hot, the cold, all the stuff in the universe
that's fascinating and beautiful and amazing, and explain it to
you in a way that we hope you actually understand
and hopefully even enjoy. Yeah, and sometimes on the podcast,
we like to talk about predicting the future. What's gonna happen,
what's gonna happen to the universe, what's going to happen

(01:53):
to the Earth, what's gonna happen to the solar system,
what's going to happen to this podcast? Where is this
podcast going anyway? Yeah, we like to talk about what
science does and doesn't know about the future, what we
can predict about what's going to happen, and where we
are totally clueless. Yeah, well, as I was we were
saying earlier, there's a there's a fine line between being

(02:14):
a psychic and being a physicist. I would say it's
a bright but fine line. It's right, Okay, it's an
impenetrable barrier, quantum barrier. It's difficult to tunnel between being
a physicist and being a psychic, but in some sense
we do have the same job. Physics also wants to
predict the future. Yeah, that's kind of. I mean, that's
kind of why, in a way, physics was invented, right,

(02:38):
Like we want to know where this catapult payload is
going to land. We want to know how far my
car is going to go? Were you there when physics
was invented? I didn't get invited to that meeting? Oh yeah,
and you didn't? Um? I think Einstein was there and
Newton was there, and damn I knew I should have
checked my email that day. He missed the calendar invite.

(02:58):
That's right, And all those exams, as you mentioned, are
totally valuable and our examples of why science has an
impact on everyday life. You know, is my catapult going
to get over those castle walls and this kind of stuff?
But also physics just wants to understand what's going to
happen to us, what's our fate? How can we plan
to live ahead? Um? And can we understand the mysteries
of everything around us so that we can know when

(03:20):
lightning is going to strike or when disease is going
to wipe out our cattle? Right? In a way, that's
kind of the the standard for physics, right. It's like
like we we we say we understand something in a
way we can sort of predict what's going to happen.
You want to verify that your theory of physics describes
the real universe out there and not just some idea
in your mind. You have to make a testable prediction. Einstein,

(03:43):
for example, predicted how light was going to be bent
during an eclipse, and people measured it and he was right.
And that's really when people started to believe his theory
of relativity. Because if your theory can't predict the future,
then what uses it, Right, That's what science does. It
predicts the outcome of future elements. Yeah, and you know,
I think people are comfortable with this idea that physics

(04:05):
is able to some degree predict the future. Like if
if you told somebody, hey, physics predict that the Earth
is going to be around for a very long time,
or that the universe will never end that those are comforting,
or if you eat that candy you will get bad. Yeah,
I think that's a that's more of a physical education. Um,
there's physics there. You're converting candy energy into squishy stomach energy. Yeah.

(04:31):
So we're comfortable I think with some physics predicting some
things about the future. But I think we're a little
bit uncomfortable about physics describing other things about the future, right. Yeah.
We like to use physics and science to explore the
universe around us and outside us. But then sometimes we
turn that science on ourselves and we seek to gain
insight into how we work. And then that makes you wonder. Yeah,

(04:54):
it makes you wonder if you are predictable in a
way you know, like could physics but actually one day,
you know, simulate the human mind, or simulate your mind
and predict what you're gonna think and do. It's a
fascinating question because so many things that humans have puzzled
over for so many years, how eclipse has happened, where

(05:14):
lightning strikes, all this stuff, how reproduction works. All of
these things have in the end been explained through science.
It turns out they are mechanistic. We can understand the
microscopically how it works and predict what's going to happen
in the future. And so then it's a natural question
to wonder how far you can extend that strategy. Can
you turn that around and extend it into your own

(05:35):
inner life? Right yeah, because you know, like if physics
can predict what, uh, you know a can of gas
particles is going to do. Why can't it predict what
a brain full of neurons is going to do? What's
the difference in the end between a can of gas
and a brain of neurons Really depends on the person probably,
but it depends on what that person eight recently. Yeah,

(05:57):
So it's a big question with I think some really
deep philosophical implications right about who we are and whether
or not we're predictable, or whether or not we have
this thing called free will. Yeah, that's right. Like many
of the topics we touch on in this podcast, there
are deep philosophical implications, and so I think today we
should walk carefully and focus on the science and then

(06:19):
think about what the philosophical implications are of what we
do and do not know. Yeah, and so today on
the podcast, we'll be tackling the question can't science predict
what you're going to do? And I predict that there
will be a lot of predictions in this episode, but

(06:40):
maybe not a lot of answers. Well that's sort of
our specialty, right, opening questions and not really answering that.
I think what you mean is getting people excited about
the questions, right, and that's right, sparking people's fundamental curiosity.
I think it's I think it's wonderful to talk about
things that we don't understand very well, because hopefully it's

(07:03):
a preview for what's going to happen in the future.
It's like a fantasy for future science. Maybe in five
years or in a thousand years, Signs will have figured
out the exact workings of the human brain. It can
tell you exactly what you're gonna do tomorrow. That would
be amazing. We totally change the way life operates, the
way what it's like to be a human being, right, Yeah,
I mean, we wrote a whole book about all the

(07:23):
things we don't know, Daniel, I'm sure we can pull
off a podcast also, I predict we will. So. Yeah.
So this is an interesting question, and it's kind of
goes back to a long time ago, when you know,
once Signs started seeing that the universe was what they
called deterministic, meaning like like just the giant machine that

(07:45):
follows the laws of physics like a clock. Then I
think that's when people started to think, like, hey, maybe
maybe our humanity is also predictable like a clock. Yeah.
I think that's sort of shocking. I think when people
first had that idea, it might have been a terrifying
moment to imagine that this experience they're having might actually

(08:06):
just be explainable, that things could be determined from the past. Yeah. Well,
I think if you told my eleven year old self
that I was a robot, I'd be like cool. Nowadays, though,
you know, it's more of an uncomfortable statement. You're a
robot and we gave the remote control to your sister. Sorry. Yeah, no.

(08:27):
I think also it's fun to think even more deeply
into sort of the origins of human thought on this question.
Is the sort of the hubrist that the universe is
explainable at any level? You know, I think a thousand
years ago or five thousand years ago, people might have
been comfortable with the idea that the universe doesn't follow laws,
it just sort of is, and maybe there are these
omniscient sentient beings out there that are in control of

(08:50):
stuff and they can do whatever they like. So the
idea that the universe that we could write down rules,
we could discover rules that the universe follows and use
those to predict what's going to happen. That's an incredible
step forward in human intellectual history. But also it's not
something we can necessarily explain, like why would the universe
be deterministic? Why would the universe even follow laws? Is

(09:11):
it true even today, given our amazing success in science,
is it true that everything we can discover, Um, every
natural phenomena we discover will eventually be explained by science
or can be explained by science. Those are open questions
in philosophy. Yeah, and so I guess the question then is,
you know how far can we push science? Like if
science can predict the future to some degree, like you know,

(09:33):
I can predict that the airplane is not going to
fall from the sky, or it's going to predict that, Um,
you know, if I shoot this laser, this is what's
gonna happen. You know, how far can we push the
science and maybe even predict what your brain is going
to do? Fascinating questions. And I think you'll see from
some of these reactions that there's a wide variety of
opinions out there. So, as usual, I walked around campus

(09:56):
at you see Irvine, and I asked folks this question,
can science predict what you're going to think or do?
So think about it for a second. Do you think
you're just a big, squeehy biological robot machine or do
you think you have some sort of free will or
some sort of free spirit that nobody can predict what
you're going to think or do. Here's what people have

(10:17):
to say, not precisely to an extent. There's just so
many variables. No, no, not um, because we're humans are unpredictable.
I'm a psychology aager. So yeah, I don't believe that
we can. We can try, but it's not likely. Yeah,

(10:39):
I think so, you think so? Yeah, So then is
their free will in that case? Yeah, because it's still
the person that'slf, that's stims, just the other person that's
from the predicting correctly, So it's not their choice theoretically.
I mean, if we did have these capabilities, then that
might be possible. We just need to advance. Science is

(10:59):
far enough to able to figure that out. No, I don't.
I don't think so. So do you think the brain
is like not described by physical laws or does something
else happening there? No? I think, UM, strong determinism I
think is a very uh optimistic Yeah you do. Why
is that? Um? I don't know. I just feel like

(11:20):
it could, and if it does, does that mean that
you have free will or don't have free will? Or um?
If you can predict what people are going to think,
then probably not. Yes, yes, Why is that? I don't know.
I think I saw like a video where they're like
trying to map out like a brain or something, and
they were talking about like how to recreate it, and

(11:42):
that everything we think is just like a series of decisions,
and that you can put it in like binary or something,
so like zero for yes or one for no, and
it all leads to what choices you make. I think
that if there were a method for it, it wouldn't
be super exact, just because there were so many Does
that play into it. I don't think it's possible to
be able to predict every single one of them. Yes, yes, um,

(12:07):
oh no, no No. So you don't think the brain
follows physical laws. I think it does, but I think
they're chaotic, chaotic or random. I've given enough information. Are
you just a complicated mechanical watch? Uh? No. I think
I may or may not subscribe to the view that

(12:29):
there's some quantum mechanics at play. So maybe you're not
seating quantum mechanics because it's an opening for free will.
M M. Now, I don't know if that's true. I'm
I'm a pessimist. I feel like eventually, yes, but I
feel like we're not there yet. So if so, does
that mean that your brain is deterministic but you're just

(12:50):
just a product of what's happened in the past and
the stimulus it's getting. Obviously there's like some varying factories,
but I think there are some things that are like patternistic,
like if you're gonna wake up in like drink a coffee,
or if you're gonna wake up and like go for
a walk, Like those things are patterns that like are habitual.
But then there's things that aren't. I feel like you
could predict it to an extent, but not like every

(13:12):
single action by action, like there might be like faults
in the prediction. But yeah, it's hard to do because
it's impossible. Just I feel like that's probably impossible because
your things can change, you know, very complicated robot. Does
that mean that there's no free will? I currently thinking

(13:34):
that there's no free will. Yes, Yeah, So maybe that's
where it becomes a bit complicated to answer this question,
because I do believe that the laws of physics govern
everything in the universe, so that would include us, all right.
I feel like these answers were all very yes and no.
You know, some people were like no, some people are

(13:55):
like yes. Nobody said like maybe, I don't know, you know,
like people had very opinions. They certainly did, and I
should have taken some data to see if these were
like all science majors who had confidence as science would
eventually figure it out or not. But the last two
were maybe the most fun because they turned out to
be a husband and wife and he said, yes, he's
a complicated robot and she says, no, we're not robots.

(14:18):
And then after I left, I heard them arguing about
it in a good natured way. In a good natured way, Oh,
I see one of them. One of them thought that
the other one was predictable and the other one did
not like to be predicted. Yeah. I thought that was fascinating.
Maybe sparked some dinner table conversation. But you're right, and
and in contrast to some other questions, this is definitely

(14:40):
a topic everybody felt comfortable giving an answer to. Sometimes
I'll ask people a question and they'll be like, what,
I never heard of that before or I don't know,
but here everybody had something thoughtful to say. Yeah, because
I think it touches something very deep within us, you know,
just this idea that there's something more to me than
just like a big biological clock or a big biological

(15:02):
you know, clump of cells doing what there would do
without thinking about it. Yeah, I think most people feel
like they are steering, even if your body is a
big biological robot. They feel like they're in charge. They're
making choices. They decide to eat that cookie, or they
decide to step on that crack. They feel like they're
making these decisions and so so and so. It doesn't
sort of jibe with that experience to imagine that those

(15:25):
decisions are just the product of the situation you're in
an instant before. It's hard to imagine how you could
have such a visceral experience of free will if you
don't actually have it. All right, so let's stick into
the question. Here is the question here, which is a
cook science predict what you're going to do. And so
let's maybe paint the picture to our listeners about what

(15:47):
that might look like. You know, like, how could science,
physics or you know, a combination of biology and computer
science possibly predict what a human brain might think or do. YEA. So,
the typical raggy for understanding something is to think about
it in terms of its microscopic bits, like what's going
on inside of it? Can we understand those bits and

(16:09):
from that build up some sort of understanding, you know,
like if you wanted to say understand how a watch worked,
you would take it apart and you would say, oh,
there's a gear here, and there's a lever there, and
this lever touches that gear which turns this thing, and
that's how this thing works. And if you can make
a model of all the things inside of it, and
each one of those things is following the laws of physics,

(16:30):
then together the whole thing has to follow the laws
of physics. Right. If something is made up of pieces
which are predictable, then putting them together it should also
be predictable, right you mean like a so science would
might be maybe break down your brain and maybe build
like a computer model of each one of your neurons

(16:51):
and that somehow, you know, acts exactly the same way
that is put together the exact same way that your
brain is. And so maybe like if you capture your
brain in a computer, could that maybe predict what you're thinking,
what you'll think and do. Yeah, And it doesn't have
to be a computer model in the end, it just
has to follow the mathematical laws of physics, and you

(17:13):
can express those as a computer model. You could also
build a mechanical model. You can imagine building a basically
a physical copy of your brain. So that's I think, uh,
that detail is not critical the concept. The critical concept
is understanding what's going on inside the little bits and
then build putting those together to basically replicate your brain.

(17:33):
But replicating is not enough. Like if I had a
perfect copy of your brain, Like if I created another Hooge,
that wouldn't necessarily help me understand what you're going to do.
In order to in order to predict what you're gonna do,
I need to be able to run experiments. And so
you're having a simulation of your brain. I could like say, well,
what would Hooge do if I offered him a cookie?
Would he say yes or no? So if I had

(17:54):
a perfect simulation of your brain, I could run those experiments, right, Yeah,
I think it goes to the idea that you know
we're really complicated as human beings, as thinking beings. But
you know, if you break down our brain, it's made
out of you know, lobes and chunks of brain tissue,
and those are made out of neurons connected to each other,

(18:16):
and neurons are made out of molecules, and so all
of these things down to the molecule level kind of
follow the laws of physics. You know. It is sort
of at the end, just a big and very very complicated,
but still a big clock. Yes. And that's a really
deeply powerful implication of this discovery that we made a
long long time ago, that everything is made out of

(18:37):
the same bits. Right, I'm made out of atoms. You're
made out of atoms. This chair I'm sitting on is
made out of atoms. Things are not made out of
their own kind of stuff, which means that they in
the end, they all follow the same rules. The rules
that hold a chair together are the same rules that
hold your cat together, and your hamster together and you together.
So if we can figure out what the rules are
that describe how molecules and atoms work, that improve instaple.

(19:00):
And that's an important distinction and principle we should be
able to extrapolate it up and understand how you work. Right,
It's kind of like saying, like, you know, we are
made out of inanimate bids. You know, I think we're
made out of things that are just plain things which
you can maybe predict what they're going to do. And
so does that mean that we are also inanimate in

(19:22):
a way unpredictable. Imagine you came across a robot, for example,
and it was doing weird stuff and you want to
understand it. How would you understand it? What? You would
take it apart and say, oh, it's made out of
these pieces, and can I understand each of those pieces?
And if so, you could put that together to an
understanding of the whole robot. And so the idea is
apply that to a person. Yeah, and you could do
things like, you know, if I, you know, if I

(19:43):
poked this little bit here in this engine, you know,
I predicted the and the car is gonna move forward
or backwards exactly. And all of this happening, of course,
assumes a few things. It assumes that you can get
a picture of what's what's happening inside your brain. The
idea you presented for choirs that we know each neuron,
we know the situation that neuron is in, right, It's

(20:04):
like for the watch, it's like that we know where
the levers are and where the gears are, and that
we can extrapolate up from those levers and gears to
the operation of a whole brain. That's not trivial. And
then you know, there's questions about like is it actually deterministic,
or is there like some funky quantum magic going on,
or is there something in there that like science can describe.

(20:26):
So it's not a trivial thing to say just just
because your brain is made of atoms that we could
therefore predict what you're gonna do. Right, Yeah, I think
that's the at the core question here, And so let's
get into it and um, just to say, some time, Daniel,
I will always take the cookie. You don't need a
fancy computer simulation to predict that I will take the cookie.

(20:47):
All right, I'm gonna cross that off my deep questions
of the universal list. Yeah, so let's get into it
a little bit more deeply and figure out how you
might even do this, or whether we can or if
there is some kind of quantum magic that might give
a little bit of a loophole to get free will.
But first let's take a quick break. All right, we're

(21:17):
talking about whether science can predict what you're gonna think
and do, and we talked about, um, yeah, that maybe
your your brain is made out of little bits and
pieces which which are sort of little biological machines. And
so does that mean that your whole brain is just
a machine or like a robot, which anyone could predict
what they're going to do? So let's get into it.
What are some of the things Daniel, that physicists know

(21:38):
or think that might make that picture really difficult or
maybe impossible to predict what you're going to do. The
first thing that comes to my mind is just knowing
the current status of your brain. Like if I wanted
to model the flight of a of a baseball, I
wanted to know exactly where baseball went. I would need

(21:59):
to know it's current position and it's current direction. If
you wanted to know if you wanted to predict where
what's gonna land, you would sort of need to know
you know where it is and where it's going at
any given time. Yeah, and and at any moment, just
one moment in time would determine where it's going to be.
So if I knew where that baseball was now and
where it was in which direction it was going in,

(22:20):
I could just apply the law of physics and propagate
that information forward. I would say, Oh, it's going to
move in a certain path under the under gravity, and
I can tell you exactly where it's going to land.
That's physics predicting the future, and that works for one
little tiny particle or baseball or whatever. But in order
to do that for your brain, I would need to
know the current situation of your brain, Like, what is

(22:42):
the situation of every neuron? Is it about to fire
a little pulse? Is it not about to fire pulse?
How strong is this connection between it and the next neuron?
And you know there's billions and billions of neurons in
your brains. We're talking about an enormous amount of information
you'd need to know. I think what you mean is
that even if I had a giant computers similiation of
your brain, I would need to give each of the

(23:02):
neurons kind of a starting value, right, or like I
would need to know where each neuron was in order
to predict what the whole brain was going to do. Precisely.
If I had a computer program that could simulate an
arbitrary brain, I would somehow need to configure it to
your brain. And that would mean knowing where all the
neurons were and how they were connected to each other

(23:22):
and all that kind of stuff. Just like if you
want to calculate where the baseball is going to go,
you need to know the initial conditions. You need to
know where it is now and which direction is going in.
So like, even if I had that computer program, and
even if it was possible um to use that computer
program to predict the future, how do I get that
information from your brain? Do I have to like scan
your brain somehow? You have to take your head off

(23:45):
and slice it into hyperfine little bits? Like how do
you even physically do that? Right? Because each neuron might
be in a different state, you know, like one win
might be more excited than others, or you might be
you know, you might be in a bad mood. And
so there's a general I don't know dopamine levels that
are you know, suppressing some of your neurons right now.

(24:05):
You need to know that in order to predict what
you're going to think and do. Yeah, And you need
to know it all at the same moment. Right, I
don't want to know what the left half of your
brain is doing right now and the right half of
your brain is doing two seconds ago. I need a
complete picture of your brain at one moment, so that
I know how what direction everything is moving in. I'm
just thinking of your brain is like a lot of
tiny little baseballs, and so I need to know where

(24:28):
all those baseballs are at the same time. So even
slicing your brain, you know, like a ham sandwich or whatever,
wouldn't work. I need to somehow instantly scan everything in
your brain. And that just seems almost impossible, right, It
seems almost impossible. I mean I read a lot of
science fiction, and there's some good stuff where the people

(24:49):
are uploading brains into the cloud, and sometimes they talk
about how scanning the brain is a destructive process, but
they never talked about how fast it has to be. Like,
if you want to scan the brain, it's got to
be a snapshot. You gotta know where everything is in
an instant or it's all averaged like over the last
five minutes or ten minutes or twenty minutes, or however
long it takes to scan the brain. And that's going

(25:10):
to be a disaster. So this is a technological issue,
not philosophical. But I don't know if that's even possible.
Oh I see, Okay, so that's kind of the first
um barrier that might prevent you from predicting somebody's brain
is getting a snapshot of it. But uh, and it
sounds impossible, but I think technically you can't rule it
out right, Like, it's not technically or theoretically impossible that

(25:33):
maybe one day people will come up with a brain
scan that can somehow capture all of your brain in
one instant. That's right, unless you need to know it's
sort of at the level of quantum mechanical objects, like
you need to know the exact location of every electron.
Then it's theoretically impossible because you can't measure the perfect
quantum state of the entire brain all at the same time.

(25:54):
I think that's theoretically impossible. But as long as it's
you know, not necessarily sensitive to quantum effects in theory,
it's possible, but technologically way out of our grasp today today. Yeah,
let's assume that that's possible and then think about what
the other problems would be. Yeah, yeah, because that's that's
not that's not the only problem is scanning your brain.
There are first we have to achieve this almost impossible

(26:16):
sounding technological feat. Then we got the real problems. Yeah, well,
you know that's what they said about the iPhone. And
look where we are now? Is that? Is that what
they said about the iPhone? Was it that? This was
that at the physics meeting you had with Einstein and
you know all those guys, Well it was science pitching
like fifty years ago, right, like this device that fit
in your pocket and you can talk video with people

(26:37):
and play addictive video games on for hours. I mean
that was like a Star trek. You know that's true.
And it'd be folly to say this kind of technology
will never be developed or would take years or centuries
or whatever, because those kind of predictions are always people
always look silly five years later after making those predictions.
So we should avoid that. And maybe technology will progress

(26:58):
rapidly and they'll invent the brain scan next week, and
they'll have a brain scan app that you can put
on your phone. Maybe, But then there are other things
that will would make this really difficult or that kind
of make your brain almost pretty much unpredictable. Right, Yeah,
there are a lot of practical issues and actually accomplishing
predicting what your brain is going to do. Say, we

(27:18):
had a snapshot at your brain, we knew the current
status of every neuron. We could load that into the computer,
and we wanted to run that forward. We wanted to say,
all right, well, what's this person going to do in
five minutes. That's not always easy. Some systems, even if
they're made of atoms which follow physical laws, and even
if you knew where all those atoms were, are hard

(27:39):
to describe. Yeah, because there um you're telling me earlier.
They're not easy systems to kind of simulate, or they're
not easy systems to um to kind of predict what
they're going to do. Yeah, and this is again a
technological problem, but it's a real problem, Like why can't
we predict the weather? In theory, weather follows rules that

(28:02):
we understand water droplets and air resistance and wind and
all that stuff. That's not complicated physics. They're just atoms. Yeah,
they're just atoms, And we don't even need to worry
about the atoms. We can think about the water droplets
and the temperature and stuff. So why is it so
hard to predict when it's going to rain or when
a hurricane is going to come. If it's following the
laws of physics, and we have amazing satellites that are

(28:23):
like gathering all this data about what the temperature is everywhere,
it's a very similar problem. The reason that weather it
is hard to predict is not because it doesn't follow
the laws of physics. It's because it's very, very sensitive
to the exact tiny details of the situation. A small
change in temperature over here leads to a big change
over there. That's something we call chaos. Right, It's this

(28:46):
idea that the kind of goes back to that whole
butterfly idea, right, Like like they say that if a
butterfly flaps its wing in one part of the world,
it can actually affect the weather in another part of
the world, just because it's so sensitive to even small
things like a butterfly flapping its wing. That's right, and
not every system is chaotic. Some things are not right

(29:08):
some things. For example, when you throw a ball, you
throw a ball, if you change the angle you're throwing
it at by a tiny bit, then the outcome is
changed by a tiny bit. Right, you throw it a
tiny bit harder, it lands, it goes a tin a
bit further. But other things, if you change how you
do them by a tiny bit, you get a very
different outcome, Like rolling a die. If you roll a

(29:29):
dice slightly differently, you spin your hand to tying a
bit differently, you get a four instead of a two,
or a five instead of a one. So the outcome
depends very very sensitive and exactly how you did it.
It's not random, it's following the laws of physics. In theory,
it's predictable, but in practice it's very difficult because the
outcome depends very sensitively on how you flap those butterfly wings, yeah,

(29:51):
or how you throw the die. Like to predict a
die roll, you would need to really kind of like
pay attention to the exact angle that each I is
at when it leaves your hand, and you have to
predict also or simulate how like when the corners hit
the ground, how that's going to affect the spin of
the die. And so it's really it's just a much

(30:12):
more complicated system to simulate and predict than like just
throwing a baseball. So then the question is, is your
brain like a big bag of dice with very each
one very difficult to predict and bouncing off the other one.
It's a very complex thing, or is it made out
of things which are easy to predict? And if you
knew pretty much the current situation that you could predict

(30:34):
how it's going to come about? You know, is your
brain a hurricane or is it just a baseball right?
Or you know, if I have butterflies in my stomach
and those they flap, what's how is it going to
affect my decision to eat a cookie or not exactly?
So the point is that even if you knew exactly
the current situation of the brain, could you have a
powerful enough computer to predict what it's going to happen

(30:55):
going forward? And in the end, that's really the limitation.
For example, for hurricanes, if we the location of every
drop of water on Earth and its current position and velocity,
and we had a super duper powerful computer, then yeah,
we could probably predict the weather very accurately. But we
don't have those computers right well, were I feel like
we're getting better though, you know, like sometimes I'm really

(31:16):
impressed by how far ahead we can predict the weather
and how somewhat accurately, we can. This is just a
hurdle of technology. Something of the fastest computers in the world,
like the supercomputers, are all devoted to this problem predicting
the future of the weather, understanding the atmosphere and all
of its chaos, and so it's really just like throwing
more computational power at the problem. Well, and that's because

(31:39):
weather is a chaotic system, right, Definitely, weather is very chaotic.
It's very difficult to predict the outcome, even if you
know the current conditions. But do we know if the
brain is chaotic or humans or chaotic? Humans seem chaoic
to me. I mean some of them I've known for
decades and I still don't understand why. Then good decisions
they do, and not just their children, not just of children. No,

(32:01):
we don't know for sure, but it seems to me
very likely. I mean, it's a hyper connected, very sensitive
set of neurons. It seems to me very unlikely that
it wouldn't be a chaotic, But we don't know. It
might be that there are sort of emergent phenomenon that
you're not really sensitive to all the little details, and
that you could build a model that predicts roughly where

(32:22):
things are going. If you don't care about the details,
you can tell whether somebody's gonna have a cookie and
who they're going to vote for the next election. It's
possible that you could build those models, but that requires
a sort of another layer of insight. Right. Imagine you
only knew the baseball in terms of little particles inside
of it. You're like, oh, there's no way I could
predict the way this baseball is gonna move. There's ten

(32:43):
to the twenty three particles. It's impossible. But if you understand,
if you took a step back and saw the flight
of it, you can say, oh, actually, I can describe
this and ignore all the particles. I can ignore all
those details they're not relevant, and I can just describe
this in terms of simple motion. So it's possible that
there's an emergent theory of psychology mathematical psychology that could

(33:03):
describe the motion of the brain. We just don't know,
or I wonder if it might vary with people. You know,
some people might be more predictable than others. Yeah, I
certainly know some people who seem pretty chaotic. All right, Well,
those are two pretty big hurdles, and but then there's
um another hurdle coming up and and or possibly a
loophole that might still let us have some free will

(33:27):
in this deterministic machine like universe. So let's get into that.
But first let's take a quick break, all right, Daniel.

(33:47):
The last topic here is about randomness and whether randomness
at the quantum level can maybe effect what we see
as free will, or whether it can affect with or
not we can predict what people will think or do.
The whole premise here, The assumption we're making is that
the brain should be predictable if it's various bits are predictable,

(34:08):
if it's made out of predictable bits, then you should
be able to put those predictable bits together into a
predictable brain. But listeners of the podcast are probably wondering,
are those bits predictable? The brain is made of atoms,
and atoms are made of protons and electrons and all
this stuff, and we know that those things are quantum mechanical,
and we talked on the podcast recently about the crazy

(34:28):
probabilistic nature or quantum mechanics, that things are not determined
until their measures, that there is really true randomness at
the quantum scale. So you might be wondering, how can
you build determinism on top of this fuzzy quantum randomness. Yeah,
because we talked about some of the challenges, right, We
talked about scanning your brain and about chaos, and but
those are technical problems. You're saying that maybe just in

(34:52):
the bits themselves of the brain, there is some inherent
randomness that might make it impossible to predict. Absolutely, we
know that there's inherent randomness. Everything, as we say, is
made of atoms, and those things are governed by fundamentally
quantum mechanical properties. What we don't know is if that matters, right,
It certainly doesn't matter for predicting the motion of a

(35:14):
mechanical watch. People can build mechanical watches that are super
accurate for years at a time. We can predict the
flight of a baseball without even knowing that quantum mechanics
was the thing. I remember. Quantum mechanics affects things only
on super duper tiny scales. The uncertainty principle delta x
delta P the relationship between the uncertainty and motion and position.

(35:36):
The uncertainty there is is related to this. Planks constant
each bar, which is like the fundamental unit of the universe.
But this is a super tiny number. It's ten to
the minus thirty four jewels. And so it might be
that on top of the quantum randomness, we do have
a layer of physics which is deterministic. Or it could
be that you know that the quantum randomness sort of

(35:57):
seeps up from below and affects the world working of
the brain. Okay, so you're saying that there is a
fundamental randomness in the universe and in my brain cells,
Like at the to the smallest level, I can't possibly
predict my brain, but maybe if I go up a
few levels, then the brain starts to be more predictable.

(36:20):
We see this in physics. We see at the very
smallest levels you cannot predict what's going to happen. You
shoot the same photon into the same experiment twice, you
get two different outcomes. There's really true randomness there, and
that breaks determinism. So photons not deterministic, electrons not deterministic.
Protons not deterministic. But somehow, when you put these things together,

(36:42):
you put enough of them together, all those random fluctuations
average out that basically cancel each other. This is a
deep theorem in physics. It's called the air infest theorem,
that you have enough of these things and it doesn't
matter anymore as long as you're measuring things on the
sort of classical scale and sizes that we care about centimeters, millimeters.
Even then the quantum mechanic effects average out, which is

(37:03):
why we didn't notice quantum mechanics for thousands of years.
It's hidden inside the summation of all of these quantum
little events. Yeah, which is why it was so hard
to accept. Right, we had just accepted the mind boggling
consequences of a deterministic universe, like, wow, the universe seems
to follow rules and we can predict it. And then
we discovered, oh, actually no, at its deepest level, it

(37:23):
seems weirdly random. And that was totally in contradiction with
everything we thought we understood, which is why quantum mechanics
are so counterintuitive and so fuzzy. But still, it didn't
mean that all those things we learned were wrong. It
just meant that they applied to sort of the larger scales,
that those same rules can't be applied to electrons and protons.
But they can still be applied to baseballs and watches.

(37:46):
So then the question is is your brain a baseball
and watch or is it an electron. Yeah, it's kind
of like if I said, um, hey, Dana, I'm gonna
flip this coin, and if it's head, i'm gonna take
your cookie, and if its tails, I'm not going to
take your cookie. Then it then it's kind of like
then you might say it's unpredictable what am I gonna do? Right,
because you don't know except that a coin is deterministic.

(38:07):
A coin is a classical object. If I knew exactly
how you're gonna flip it, I could predict exactly how
that coin was gonna land, and I would know that
you were going to take the cookie no matter how
the coin flipped, actually, because I know you as a person,
but but yeah, exactly the coin flip is not written.
But if you, for example, how a radioactive particle and
you said, I'm gonna wait one minute. If the particle

(38:28):
decays in within this minute, I'm eating the cookie. And
if it doesn't decay within this minute, I'm not eating
the cookie. Then I can't predict whether or not you're
gonna eat the cookie. That's because you linked a macroscopic
action eating the cookie to a quantum mechanical thing. That's rare. Right,
that's a whole Shrowdinger's box argument. It's very difficult to
find quantum mechanic effects that you can see on the

(38:48):
macroscopic scale. Oh, I see, like, if if I made
my cookie eating dependent on whether this particle decays or not,
then it's unpredictable. But if I make my eating the
cookie depending on whether the particle will decay over a minute,
then we know a lot more. Right, it's less unpredictable

(39:10):
because you know that on average, most of these particles,
let's say, like these particles decay within a minute. Yeah,
that's true. And if you want to make statements about averages,
then you're a rock solid footing even quantum mechanically, because
quantum mechanics doesn't mean things don't follow laws. It just
means those laws are probabilistic. And so you can say,
on average, this is going to happen. On average, that's

(39:31):
gonna happen for one particular particle. You can't make any
predictions on a quantum mechanical scale, but you know what
quantum mechanical effects do you observe as a person, Like
for quantum, for something to affect your life that's really random,
it has to have an impact like that somebody's measuring
this quantum mechanical thing and making a decision based on it.

(39:51):
It's really pretty rare for quantum mechanical randomness to affect
the macroscopic world. People do really complicated experiments to try
to set this kind of thing up. Bose Einstein condensate.
It's like a macroscopic quantum state that you can see
that actually behaves quantum mechanically. It's really weird and amazing,
and people want the Nobel Prize for that. So two,

(40:12):
for the brain to be dependent on quantum mechanical randomness,
you'd have to show somehow that like the motion of
these electrons and this weird quantum mechanical effect was triggering neurons,
and neurons were somehow sensitive to these things. Yeah, So
it's so it's it's it's fundamentally random. But the question,
it seems like the core and the key question here
is whether that randomness at the quantum level really affects

(40:36):
whether I'm going to eat my cookie or not, or
whether that all gets drowned out by the Brazilian electrons
that I have in my brain. And there are some
folks who have made that argument, and I think that
that argument is largely in response to fear of determinism.
They don't want to think that the that the brain
is just a mechanical watch that can be predicted. So
there's sort of striving for some way to leave a

(40:58):
window open for free will. And they, oh, well, if
we can connect it to quantum randomness, then you know
you can't be predicted and therefore there might be room
for free will. And famous people like Roger Penrose make
this argument, but it's just a it's more like a
an outline of an argument. There's no evidence that the
brain is dependent on quantum mechanic. It's just like, can
we find some path maybe go down that leads us

(41:20):
to a nondeterministic brain. There's no real evidence or argument there.
It's just like a suggestion. Well, the I think the
thing is that it's it's a it's a yes or
no decision, right, whether I eat the cookie, it's either
yes or no. So I'm kind of like sitting on
the edge of a really thin knife, right, and you
know who knows. Are you can you really rule out

(41:42):
that you know how one particular electron behaved it was
resulted in pushing me one way or the other, Or
are you saying that pretty much that's unlikely. No, I'm
not saying that we can rule it out at all.
You're totally right, and it could be that there are
quantum mechanic effects that determine whether you make that decision.
It's possible, but I'm saying we have no evidence for that.

(42:04):
Nobody has shown that we don't even understand the mechanism
of it. That doesn't mean it's not happening. It just
means that it's more of a suggestion, an open door,
than an actual idea. All right, well, I feel I
feel pretty good. I feel like we um we're right
where we predicted we would be. I think you deserved
a cookie or a banana at the very list. Oh no, wait,

(42:25):
do you say? I would say, there you go? But
I think that there's some fascinating questions there, like even
if you knew the answer to this question, even if
you showed that the brain was deterministic or wasn't that
the brain was quantum mechanically random, what would that mean
for this experience of free will. Let me see if
I can readat what we learned. We learned that it's

(42:46):
predicting what people are going to do is super technically
hard with the scanning all of the neurons in your
brain and chaos maybe playing a large party making it unpredictable.
But let's say like we invented technology to take care
of that, there's still sort of the question of whether
randomness trickles up to influence decisions, you know, randomness at

(43:09):
the quantum level, whether that trickles up to influenced decisions,
And it sounds like we we we don't know. It
sounds like we can't say either way. That's right. Quantum
mechanics might make it theoretically impossible to predict the brain.
We don't know, And if it doesn't, if it doesn't
make it impossible, and we know, it's still super duper
hard because you need to know the exact state of

(43:29):
the brain and you need to overcome the potential overwhelming
chaos of your billions and billions of neurons. So even
if it's not impossible, it's definitely very very tricky, right,
And then we could probably have a whole podcast just
on the implications on how we feel about free will
and whether it would still exist even if it was
governed by quantum randomness. That's right, And this is an

(43:51):
area of philosophy, And neither you nor I have formal
training in philosophy. What do you mean have a doctorate
in philosophy in engineerings. So then let me ask you, Jorge,
if I could prove that you were deterministic, does that
mean you don't have free will? This being a big
mechanical robot mean you're not making choices? Or is that
just describe the choices you are you are making? I

(44:15):
think that would be bananas. No, I think for me
it sort of doesn't matter. I feel like it doesn't matter.
I'm not I'm not someone who sweats free will too much.
To be honest, Like, I feel like it might be
a robot. That's fine, And um, you know, currently it's
almost like who would want to predict what I'm going
to do? Do you know what I mean? Like, it's
such like, why is this problem even interesting? Who would

(44:37):
take the time to care about what I'm going to
think and do? Um? So, as long as nobody else
can think or would want to know, what I think
and do. Then to me like, okay, I could be
a robot or I could not be a robot. Well,
I think there's an implication of moral responsibility. We've been
talking about you eating a cookie. What if that was
somebody else's cookie, right, and you ate that person's cookie,
Then could you say, Hey, I didn't make that choice.

(44:59):
I have no free will, and therefore I can't be
more morally culpable. If everybody is deterministic and people aren't
making choices, than our sort of whole theory of morality
kind of falls apart and we can't really punish anybody
for anything. All right, we'll say that. For our other podcast,
Daniel and Jorge explain the Moral Universe. Daniel and Jorge
um blather on about philosophy. They don't really know what

(45:21):
they're talking about. I would listen to that, and I
predict that a lot of people will probably not. But
I think these are, like many of the things that
we talked about on the show, there are deep implications
for just what it means to be human being. Often
we talk about how the universe was created and how
it came to be in his future, and that has
deep importance for people, how what people think about their

(45:43):
place in the cosmos and how they should live their lives.
And this is similar. It's a question, you know, is
this the threshold that science will ever cross? And if so,
what does it mean? And so I love the fact
that science is so relevant sometimes that everything touches the
deep core of how you're gonna live your life and
what it means to be human. Yeah, it's amazing to
think that physics can have such an impact in who
we are as a in our souls, in our conception

(46:06):
of who we are. Well, physics is deep in my
soul and now maybe you're discovering it's actually deep in
your soul as well. We got you, We infected your soul,
dear audience, physics. All right, Well, thanks for joining us.
We hope you enjoyed that, and we hope that meant
all of your expectations. But what this podcast was going
to be, that's right. Thanks for tuning in. And for

(46:27):
those of you who wonder whether science can actually explain
the universe, remember that we don't know. Science has worked
pretty well so far and been able to explain a
lot of what we've seen, but there might be some
day in the future where we find some phenomenon that
can't be explained by science, or by our current visioning
of science or our mathematical rules. So we are continuing
on this journey of trying to explore and explain the

(46:49):
universe we find around us. Thanks for joining us, see
you next time. Before you still have a question after
listening to all these explanations, please drop us the line.
We'd love to hear from you. You can find us
on Facebook, Twitter, and Instagram at Daniel and Jorge That's

(47:11):
one Word, or email us at Feedback at Daniel and
Jorge dot com. Thanks for listening and remember that Daniel
and Jorge Explain the Universe is a production of I
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