November 27, 2018 • 37 mins
If you repeat the same experiment, do you get the same outcome?
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Speaker 1 (00:07):
There's a core idea in science that experiments should be repeatable.
If you do an experiment the same way at different times,
you should get the same result. However, there is a loophole.
There's a loophole in science. Yeah, and that loophole opens
a window into everything we think is true about reality
(00:28):
and the universe and everything. Doo doo doo doo doo
doo doo doo doo doo doo. Welcome to Daniel and
(00:50):
Jorge explain the Universe, in which we try to take
the entire universe and break it into bite sized pieces
so you're gonna enjoy them with your afternoon coffee. I'm alright.
I'm a cartoonist. I draw comics online, and I'm Daniel.
I'm a particle physicist. I spend my days smashing protons
together at the Large Hadron Collider to try to reveal
the secrets of the universe, mostly so that I can
(01:11):
tell them to you in this podcast. Basically only one
of us is qualified to be explaining things to you
on this podcast. That would be the cartoonist business. They're
not qualified usually to be explainers. Mostly we just try
to solve the mysteries of the universe. We don't try
to tell anybody about them, right, Mostly physicists just need explaining,
that's right, that's where the cartoons come in, right, And
(01:33):
spouses also, spouses physicist probably have to do a lot
of explaining. You've got some explaining to do, exactly. Yeah. Um,
So we're here to talk to you about big questions
about the universe. And today's question is a really deep
and basic question, and it's about the very nature of reality.
What is it? Hory? What are we gonna talk about today?
(01:54):
Is the universe random or is it just chaotic? And
what the difference? Or is it run by some super being?
And we're actually just in their simulation. But that's a
whole other episode. That's a whole other podcast. Right today,
just the two sinister options, random or chaotic, you might
feel like, oh, neither of those sound very cozy. I
(02:14):
don't want to live in either of those universes. Well,
the question basically breaks down to is the universe predictable?
Like can you predict what the universe is going to do?
Or is it that nobody can predict what the universe
is going to do? Right? And I think that's why
It's an awesome question for science because for so many
thousands and thousands of years, I think humans probably felt
(02:36):
like the universe around them was totally unpredictable. I mean,
they invented gods for this and for that to try
to describe how the universe was out of their control
and doing things that didn't make sense, as if it
had some you will and agency. Right, and then science
comes along it says, actually, there are rules and you
can discover them. And slowly science starts to creep in
this description of the universe that locks out this agency,
(02:59):
this idea of this personality, and gives you the sense
that maybe the universe follows these rules. Right. So we
went out and as usually, ask people on the street,
do you think the universe is random or chaotic? And
here's what they had to say, that's gonna okay, that's
a that's a thinker right there. I would say truly random.
(03:21):
With randomness comes chaos. You never know what I what
will happen, but there's there's always a probability and a
chance of things, of certain things happening. I'd like to
say random. I'm religious, so I feel like everything happens
for a reason. And yes it is random, but there's
a purpose behind everything. I think it's a mixture of both,
(03:42):
like like it's random, but it can appear chaotic because
of how everything is truly chaotic, because like on a
smaller level, everything is like moving really fast, but at
like a bigger level, we we don't see any of that. Wow,
So what do you think of those answers for I
think they were all over the place. They were actually,
(04:05):
um kind of random. They were random and chaotic. I
feel like I feel like people had no idea what
I was asking them. You know, I feel like people
just I feel like they had no idea what they
were answering. You know, some of those people I remember
recording these interviews, and some of those people, as the
words were coming out of their mouth, I felt like
they surprised them as much as they did me. Like
(04:25):
it was all over the place. Yeah, well, I feel
like some people it's interesting. Some people related to the
question that question to the other question, which is like
does the universe have a purpose, Like do things happen
for a reason or do they is it just like
a random role to die and nobody is really in charge?
Like that's the question, right, like, is somebody in charge
of the universe or is it impossible for anyone to
(04:48):
kind of predict what it's going to do. Yeah, I
think you're right. That does get at the heart of
the question. You know, what's going to happen in the
universe and can we tell and can we influence it? Right?
Is the universe sort of churning on without our ability
to change direction at all in some sort of way
that's been determined since the dawn of time? Or can
we nudge it and push it in one way or
the other? You know, make the calves a win? Or
(05:08):
can you if you jump up and down in front
of your television enough where the Warriors win another NBA championship?
You know, can you influence the world? I think that's
a that's an interesting and deep question. Yeah, that's probably
the one people were actually having in their mind. Yeah,
so maybe let's go back in history, and I like
how you think about this question a lot, Daniel, which
is that you sort of start with early man like
(05:29):
the cavemen and women and women early humans. Um, we're
really just kind of at the mercy of all the
elements and all the animals out there, and the weather
and so they to them, the universe was this crazy,
random and chaotic place, right, Yeah, And it actually touches
on sort of my personal theory of consciousness, which is
that we developed this awareness because we are looking out
(05:51):
into the world for other people or other ideas, are
their intelligences, and we have this hyperactive ability to see agency,
to see intention in something that we don't understand, and
we imagine that there must be a mind behind it.
And so I think for a long time people's view
the world was that it was controlled by other greater minds.
You know, what controls the lightning? Why do some people
(06:12):
die of disease? All this stuff? And then as there
must be like a consciousness that is shooting out these
lightning bolts or making it rain, or you know, making
the sun come out, or killing my baby of some
horrible disease, right, like, there must be. It's hard to
live in this world if you don't have the sense
that there's somebody else in charge. Right There's a lot
(06:32):
of suffering and a lot of pain, and a lot
of unexplained events, and it's nice to think somebody else
out there is taking care of it, or somebody's in
charge of it. But there's a reason, right yeah, that
there's a reason, that there's some design, it's not just random. Um.
But then as history progresses that we were saying earlier,
you know, sigence comes along and says, well, there are
seemed to be some rules, not just like that anything
(06:54):
can happen. You can't have an ostrich here and then
all of a sudden the ostrich is gone. There are
some rules that limit what can happen. If you know
what's happening now, there's a certain set of possibilities for
what can happen in one second, in two seconds. And
you know that's physics, right Well, it's it's started with
like noticing patterns, right Like lightning doesn't just come out
of nowhere, it comes out when there's these dark clouds
(07:16):
in the sky, right yeah, absolutely absolutely, And people started
noticing patterns and started putting those together and then asking themselves,
can I use what I've learned in the past to
predict the future? Right Like, if I have the same
set of events that happened yesterday, am I gonna be
able to tell what's going to happen next week? If
the same thing happens, If I roll a ball down
(07:36):
the hill yesterday and it goes up to a certain speed,
Will the same thing happened tomorrow? Right? Right? Or if
I throw a ball in the air and I know
which direction it's going and how fast it is going,
can I predict where it's gonna land exactly? If I
build a catapult, can I basically aim it right exactly?
And that's how military technology drove science even hundreds of
years ago. Right, Where do I shoot my cannon exactly
(07:58):
to get over that wall? Well, that's kind of where
um Newton came in, right, Isaac Newton, And that's why
they say he kind of gave birth to science, right,
or at least the scientific Revolution. No, I think it
was earlier than that. Newton came along well after folks
like Galileo and and Francis Bacon and those guys. They
really were the first ones to do experiments and to say,
(08:20):
let's see what the rules the universe is following, and
let's see if we can try to deduce them and
use those to predict the outcome of future experiments. They're
really were the first ones to connect the idea of
a scientific universe to the actual experiments they do to
influence those ideas and to predict future results. And I
think that's the key is that here we've developed a
system science which cannot only explain what we've seen before,
(08:42):
but can predict the future. And you are about to
fire a cannonball at your enemy, you want to know
where is that ball going to fly? And it's incredible
that physics can do that. It can literally predict the
future if you know enough about the situation right right,
It's kind of like Google Maps. Now I can totally
tell if you're going to be late to the meeting
or not, or to a podcast recording they're gonna They're like, like,
(09:04):
how long will they need to get home? They're like,
they're gonna be late. It's not always a hard problem though. Joe.
For example, it says if person equals Jorge, then late
equals true every time, every time. A lot of data,
and some of these things are simple, but some of
these things are complicated, and it's incredible to witness as
(09:27):
physics sort of builds confidence and science develops our ability
to predict you know, chemical reactions and biological functioning, all
sorts of things, and then it gives this creeping sense
of is there anything that can escape science, Right, Can
science predict everything? Like, if you knew enough about the world,
could you break it all down to cannonballs to predict
(09:48):
where all those cannonballs are going to fly and then
tell exactly what's going to happen. Yeah, And it's it's
like kind of like if you know that force equals
mass science acceleration, like Needton figured out, um, then you
can predict things like cannonballs and catapults and and and
you could possibly predict like how a room full of
particles move, right, Yeah, possibly you can extend that to
(10:10):
can you predict how, um the whole world works? Yeah,
what it's going to do and what people are going
to do? Extrapolate to the whole universe, right, I mean,
and that's the principle of determinism. It says, Look, if
things follow rules, and the future is dependent only two things,
one the rules and two the things that are happening
now the current state. Right, given that if you know
(10:32):
exactly where things are, imagine the whole universe is just
a bunch of tiny cannonballs, and you know the rules
of those cannonballs, and you know the position and direction
of motion of all those cannonballs. Then in principle, given
a super powerful universe sized computer, you should be able
to predict the future one to five ten seconds into
the future, a thousand seconds into the future, like every
single molecule, atoms of atomic particle. You should be able
(10:55):
if it follows rules, you should be able to kind
of track where it's going to go if you tell
you based on where things are now, what's going to happen? Exactly.
It's kind of like this idea of a clock, right,
is the universe giant clock just kind of clicking along
or is there some kind of magic inside of it
that makes it unpredictable? Right exactly? And the idea of
(11:17):
the universe just being a huge clock, is both exciting
and terrifying. Right. It's exciting because like, wow, can you
imagine we could understand the universe that well, that we
could predict the future, think about what we could do, right,
But it's terrifying because it's sort of like you're trapped
in this science cage where you have no influence over
the world and everything you do and know and say,
and that joke you're going to make in that fart
(11:38):
you're gonna let slip are all predictable? Right, all those
things are predictable. That's scary. It makes you feel like
you are part of that watch and you're just clicking
along because of the the you're reacting to things around
you and your initial conditions, and so that's terrifying. And
I think we have kind of in anate sense of
like rejecting this idea that we're trapped, right we everyone
(11:58):
wants to feel like they have free will, like everyone
wants to know that they have a choice, right. Well,
I guess so my kids don't feel that way, you know,
like why did you hit your sister? Well she hit me,
you know, like, well, so what you have no free will?
Like you're completely determined by her behavior. Um. I have
that argument with my kids so many times. I'm always
thinking about the philosophical echoes of that. Um. Um, My
(12:20):
kids are always rebelling. They're like, we want free will,
don't tell us what to do, but they want you
to follow rules. They're like, you promised daddy we could
have ice cream, right, and so therefore you have to
there's no more decision to be made. Kids are so
unfair there, philosophically inconsistent. I think it's really the problem
with kids Yeah, they're cute, but if they just read
(12:43):
some more nice you know, and some some carl and
some paper or whatever, they would be easier to be around. Yeah,
forget those picture books. Let's introduce let's predict the universe.
(13:07):
I think there's something fascinating about the deterministic view of
the universe. But probably people out there thinking, Okay, maybe
in theory you could predict the whole universe, but in
practice that's impossible. I mean, you don't have a universe
sized computer to break the whole universe, and even to
predict like you know, a person is a huge number
of articles, and so to do that calculation just seems impractical, right, right,
(13:29):
It's practically impossible. But I think people reveled just to
the idea of it, right, Like, are my thoughts my
thoughts or just something that I'm programmed and that I
will inevitably have and do. Yeah, and that's a really
deep question. And so um, we started out with prehistoric
man feeling like the universe is full of random of
not random, but unexplained agency and intelligence all the way
(13:52):
to like now, scientific physical determinism says, actually the universe
just clicks along like a watch, right, and there's no
free will. So let's take one step back from that,
and that's chaos. That says, well, maybe the universe is deterministic, sure,
but that doesn't mean it's necessarily practical for you to
predict it because the way things play out is really
(14:13):
sensitive to exactly how things started. Well, I think I
think some people who responded to their question maybe weren't
sure about the difference, right, Like, what's the difference between
something being chaotic and something being random? Right? And so
let's drill into that. So let's take, for an example,
the roll of a dice. Right, people think of rolling
dice is random, but actually it's chaotic, meaning that it's
(14:35):
hard to predict, but it is deterministic. What do you
mean if you knew exactly how I threw the dice,
like exactly the direction and the spin and all the
molecules of the air, then you could treat the molec
little cannonballs, little particles, and you could model how it rolls,
and you could, in theory, predict exactly how the dice
rolled every time, meaning like if I if i'm if
(14:56):
I'm seeing footage of you throwing to die, and like
like I pause the video just as to die leave
your hands, then I could you know know where they are,
I know which direction are going, how fast are going.
I could run some kind of computer simulation to like
follow the die and predict what they're going to do
when they bounce off the table on roll around, I
(15:17):
could potentially predict what the die are going to show.
That's right, because we're saying that the universe in that
case is deterministic, and so you should be able to
predict the future given enough information about the setup. Right now,
that's a hard problem, and that's why we use dies, right,
because it's really difficult, and nobody can practically like bring
a mini computer into Las Vegas and use that to
(15:38):
predict who's going to win it craps, right though, in theory,
In theory, you could if the universe was deterministic but
very sensitive to exactly how somebody's rolling the dice. Right
when you throw the dice of craps, if you flip
it this way or that way, then it's going to
bounce slightly differently, and how it's going to hit that
you know, the felt on the table. It's all very
very sensitive and a very small change how you throw
(16:00):
it can result in a totally different number. That's what
we mean by chaos. It means that it's like that
the butterfly effect, right, like the idea that if you
butterfly flaps its wing here, it's going to have a
huge effect, maybe potentially on the weather and on the
other side of the world. Right, it's like a very
sensitive system. That's right. The weather is a great example
(16:20):
because we understand all the processes of weather. I mean,
it's hot air, it's cold air, it's water. We know
that stuff. It's pretty simple chemistry. But altogether, an entire
planet is really difficult to describe because it's huge and
it's really sensitive. Like, as you say, a butterfly flapping
its wings in China could change the way this air flows,
which could change the way that air flows, which bounces
(16:41):
off this building, which turns into a rainstorm, which collides
with this cloud and causes a hurricane. Right, it's not
true that every time a butterfly flaps its wings you
get a hurricane. But sometimes so. Weather is chaotic, but
it's not random, is that what you're saying? That ran like,
if we could keep track of every single butterfly in
the world flapping its wing. We would be able to
(17:02):
predict the weather if we had a giant supercomputer the
size of the Solar System. But since we don't, then
weather it seems random, but actually it's chaotic exactly, And
that's exactly what scientists are trying to do. They're building
bigger and bigger and faster computers to try to simulate
more and more of the Earth's atmosphere to get better
and better predictions of weather. In fact, I think like
(17:24):
all the top ten supercomputers in the world are devoted
to that problem, like modeling the weather, because it's important.
But you're exactly right, it's actually chaotic, meaning it's deterministic
but really sensitive to exactly how it started. But it
seems random because it's it's too difficult for us to calculate.
In principle, we should be able to, but we can't.
Another example is flipping a coin. Right, based on how
(17:46):
you flip the coin, you should be able to model
how it spins through the air and how it bounces
off air molecule and how it hits the ground and
where it lands. But it's a difficult problem. So we
can use it to model randomness to say it's kind
of like randomness. Really it's just chaotic though. But then
if I flip the coin a hundred times, most likely
half of those times will be head and half of
(18:07):
those times will be tails. Right, So where does that
fit into chaos theory? Like why is it predictable on
a statistical basis? Okay, so that's fascinating. That's an emergent phenomenon. Right.
That says if you understand the tiny little local laws
of physics, like the laws of how the particles inside
the coin move, you should be able to predict some
larger effect. And it's true, there is a simple or
(18:30):
description of that larger effect, right, if you understand how
these things work. Um, So physics works on these layers. Right.
You can either understand it a very low layer and
try to model it all the way up to a
higher layer, or you can just try to get an
understanding of at a higher layer, just the same way.
You could say, well, I can understand the way cannonball
flies by modeling all the particles inside of it, or
(18:51):
you could just use F equals m A, which treats
the whole cannonball like one particle. If that's just a
question of at what layer you're modeling something, right, Okay,
so a coin is chaotic but not actually random, but
not actually random. Yet, if the universe is deterministic, then
a coin is chaotic but not actually random. Yeah, okay,
got it, got it. But then it's the question of
(19:13):
that's the really the nugget of the question is is
the universe deterministic? Um, you know, if you have a
particle or a billiard ball or cannonball or whatever, and
you understand direction it's going, can you predict its future
out into infinity? Right? Right? You tell exactly what's going
to happen. But there's so many factors leading up to
me tossing the coin that it's so unpredictable that it's
(19:35):
it's it feels random, that's right. And so we have
to separate between what's practical and what's in theory possible.
Anything that's chaotic. We're saying, in theory, if you knew enough,
you could predict it, right, whereas but in practice that
we can't. So it's it's it's can't. So it seems random.
Random number generators and computers when they try to come
(19:56):
up with a random number, it's not really random. You're
saying it's just an algorithm. That's very that's chaotic. That's right.
Computers by construction are deterministic, right, We've built them to
be deterministic. Every time you run a program, it should
give you the same answer if you give it the
same input. Right. That's there's no way for computer to
do anything but that. It's like a series of logic gates.
(20:16):
And you know, how it's implemented is not important, but
you know it's a system for doing deterministic calculations. That's
what a computer is. So it's impossible for computer to
be truly random. All the random number generators in your
favorite Python code are actually pseudo random number generators. They're
just chaotic. They take a seed a number to start from,
and then they spin off of that and generate a
(20:38):
sequence of numbers. But if you give them the same
seed twice, they'll generate the same sequence of numbers twice. Wow.
So like if you're playing a video game and you're
inside of a virtual world, that world is totally determinating.
It's being crunched on by a logical computer. Exactly. You
do the same move every time. You'll kill that boss
character every single time, and not even in silivating games
(20:59):
like you know, like punch Out where the guy is
totally predictable, but even the more complicated ones. You know, Um,
if you're in the same world and you do the
same thing, the same thing should happen, because computers are
not capable of true randomness. Before we keep going, let's
take a short break. So the question is is our
(21:27):
universe like a computer simulation? Right? Like the question is
is is our universe also being crunched by a logical
computer that can't be random? That's right? And for a
long time people thought the universe was deterministic. I mean,
we were able to predict the outcome of every experiment. Um,
things were going along really well. And then of course
(21:47):
and throw a spaceship and landed on the moon. That's
pretty crazy, right, Yeah, that well that's pretty risky, but yeah,
um that's pretty amazing. You have to certainly have confidence
in our ability to predict the future if you're gonna
get into that can involve gets shot out into space. Right. Um, Well,
I remember in grad schlos in this classic it's called
linear dynamical systems. But I remember in class, this guy
(22:08):
was so the professor was so cocky. He's like, of
while the technologies that contributed to putting a man on
the moon, this is the one that made it happen
linear algebra. Kind of had this linear algebra equation, we
would not be able to put a man in And
so that that's how powerful this idea is, right, Like,
if you can predict efreequels in a you can put
a man on the moon. Yeah. No, it's exactly right,
(22:29):
And it's given us great power over our environment. I mean,
everything that we have is because we have mastered a
lot of the laws of our environment and use them
and bent them to our will to improve our lives. Right,
So it certainly works, and we rely on every day,
every time you get into a car or an airplane,
you rely on it working the same way it did yesterday, right, right, right,
So that's that's a relief. Um. But it was about
(22:50):
a hundred years ago when people started seeing things that
they couldn't explain, and it was quantum mechanics that told
us that maybe the universe is not deterministic. Maybe these
little particles don't follow the same rules that like billiard
balls and basketballs and larger objects follow, and maybe they're
not even deterministic. Meaning if you do the same experiment
(23:11):
twice with tiny particles, you could get different outcomes even
if you do it exactly the same way. Well, and
this all came about when people started noticing that like
light and things had a minimum size, right, Like light
doesn't come in infinitely small bits of light, Like there's
chunks of light, that's right. Yeah, Einstein was looking at
(23:32):
some experiments that didn't quite make sense, and the only
way he could explain them was if light came in
little packets. And that's what quantum means. Quantum means a
unit or a packet, and so he suggested that maybe
light comes in these little packets. But then it had
all these far reaching consequences, you know, um about light
going through mirrors and through prisms, and the way people
(23:52):
could understand that was only if there were various probabilities
for things to happen. And it began this whole revolution
of quantum mechanics, which then Einstein tried to put the
brakes on, right. He was like, way, a hold on
a second, guys, this is crazy talk. There's no way
the universe works this way, meaning like um, this idea
of quantum stuff only made sense if the universe work
based on probabilities, not like deterministically. You know, you have
(24:16):
to describe things with wave functions, and things aren't really
like point particles are kind of fuzzy things. That's exactly
the point is that there's this fuzziness in the universe
and quantum mechanics because there's these minimum sized objects and
the way they interfere with each other and the way
the calculations happen. Quantum mechanics predicts that the universe is
fundamentally random, and it means that, for example, you have
(24:37):
an electron, you don't know exactly where it is. There's
a probability distribution that says, most likely it's here, maybe
it's there, maybe it's somewhere else. Is it that we
can't is it like a randomness, like we can't uh
know where it is, or that there's this trade off
between like momentum and position. Right, that's exactly the right question,
and that's exactly what people are asking. They looked at
(25:00):
these equations and they said, well, is it that we
can't predict where the electron is, like it's totally impossible
to predict, or is it that we just don't know
where it is that we haven't figured out how to
get that information, right. Does the information not exist or
do we just not have it? And so Einstein is
the one who said there must be some hidden variable.
There must be something that's that these particles are carrying,
(25:22):
some piece of information that determines exactly what's going to
happen to them, but we just don't know what it is.
To him, it was crazy to think that you could
shoot an electron into an experiment twice and get two
different answers. But that's appeared. What appeared to happen. People
set up these careful experiments where you would shoot a
photon one at a time. You would shoot photons into
(25:43):
an experiment, and every photon would do something different, and
then as you would accumulate a bunch of photons, it
would add up to give you a distribution that made
sense to you. Just the same way when you flip
a coin, you get heads, you get tails, you get heads,
you get tails. It seems random, but eventually it builds
up to fifty fifty. Right. Quantum mechanics tells us all
we can do is predict the eventual distribution. We can say,
(26:06):
if you measure a thousand electrons, some of them will
go here and some of them will go there. It
says you can't predict any individual one. All you can
predict is the distribution of outcomes. So Eisland was like,
maybe a photon is kind of like the coin we
were talking about before, Like maybe it seems random to us,
but really it's just kind of this chain of of
little local events that actually make it predictable. That's right,
(26:30):
if we knew all that information inside, Like maybe it
just looks fuzzy to us that we can't tell where
it is, but inside that particle really actually knows where
it is. It's exactly right. That's what he wanted to believe, right,
That's what he wanted to believe. And you've got to
sympathize with the guy. Right, it's hard to imagine that
the universe would not be deterministic. I mean, we spent
hundreds of years building up our confidence in science and
(26:51):
his physics, especially as being able to predict the future,
and and just of saying basically, the universe follows rules. Right,
So now all of a sudden you're telling us what
there's like dice in there is there some randomness? Like
every time you shoot an electron to your experiment, somebody
or something or the universe is making a like a
random decision about where it's going to go. It seems crazy,
So you're absolutely right. And he suggested that a simpler
(27:13):
explanation is that they're carrying along another piece of information
that we just don't have access to or can't measure,
or didn't measure, and that that's actually determining in a
totally predictable way what's going to happen to each particle.
That was his solution to the problem. Well, he famously
said God doesn't play dice, right, He's famously quoted as
saying that, I'm not sure he actually did, but it's
(27:34):
really but it's a pretty good summary of what he believed.
Fake news, well, like a lot of fake news is
a cronel of truth in it. Um. He certainly wanted
to believe in a deterministic universe and it made sense
to him. And you know what, it makes sense to me.
I mean the idea that there's like a tor random
number generator somewhere in the universe that's making a decision
(27:57):
every time you're shoot an electron into something. It's doesn't
make any sense. To me intuitively. You know, not that
the universe has to make sense to me intuitively, but
it doesn't. So you're saying the quantum mechanics says that
there is a randomness in things, And so where is
that randomness actually in like the position of particles in
(28:17):
the verse of the velocity um, in their like very being,
in their energy level? What where is this randomness of everything? Well,
there's randomness at every level. I mean there's a randomness
between every time you look at something. So say, for example,
you measure an electron, you see it's a certain place,
then you look away, right, because you can't monitor an
(28:38):
electron every moment or every nanosecond ven you look away,
what is the electron do between when you last saw
it and when you'll next see it? Meaning like, if
I know where it is and how fast it's going,
and then I look away and I look again, is
it going to be where I think it's going to be? Yes, exactly.
And so every every moment of an electron or a
particle's life is determined by quantum mechanics, which says there's
(29:01):
a probability distribution. It's not like the electron is doing
something behind your back. It's got one particular path that
you're just not aware of behind your back, and you
just don't know it. It doesn't have a specific path.
It's not like it goes from a to via a
particular path. It has a probability of different ways to
get there, and if you don't look, then it's sort
(29:23):
of doing all of them at once. They all have
different probabilities, and those probabilities are the things determined by
the laws of physics. So there's still are laws. Physics
still does tell the universe how to run. It's just
that those laws are probabilistic. It says, look, Mr Electron,
instead of telling you exactly where you're gonna go, I'm
gonna say you have a seventy percent chance of doing
this and the thirty percent chance of doing that. So
(29:44):
that's where the fuzziness and the randomness comes in. It's
not that it like it looks fuzzy, it's just that
it's just hard to predict where it's going to be.
It's impossible. You know all this information, it's impossible. It's
impossible to predict the future. Impossible exactly, you can predict
the various likelihood of the So the likelihood of that
at the particle level, but you can't say what one
particle is going to do. Now, Einstein said, that's crazy, right,
(30:07):
there's no way that's true. There must be a way
to predict it must be there some piece of information there.
And then some guys came up with an experiment. They
came up with this crazy experiment. It's based on an
idea called Bell's inequality. To test this theory, they said,
let's see if the universe is really random, or if
there's some hidden piece of information that's actually secretly determining things,
(30:28):
like let's see if if I really can't predict for
that electron is going to go, or if it's actually
like the electron knows it just won't tell us. Yeah, right, exactly. Um.
And so they set up this cool experiment where they
took a particle and they had to shoot out two
particles in opposite directions. And those particles are therefore connected
because they have to conserve momentum, they have to conserve
(30:50):
energy and have to conserve spin. And so if you
know something about one particle, that you know something about
the other particles, but both particles have equal probability to
be like spin up or spin down own, or point
this way a point the other way, but you know
something about the combination of the two. And so they
came up with this really ingenious experiment to measure how
often you saw one spin up and one's been down,
(31:11):
for example, And based on the outcome of that, you
could tell whether there was a secret, hidden um piece
of information that was controlling both particles, or whether they
were both truly random. And the experiments are conclusive, and
it's been done a zillion times, and the experiment tells
us that the universe at its core really is random.
That's making a random decision every time you look at
(31:33):
these particles. So beyond the shadow of a doubt, we
know that the universe is random. The universe is random. Absolutely.
There's no no escape clause, there's no if hands or
but there's no asteris no loopholes. The universe at the
part of the level is really random. Now, you said
something really interesting earlier. You know, even if the universe
(31:55):
is random at the lowest level, that doesn't necessarily mean
that it's a random at other levels. Right, Like we
still got to the moon. Right, It's not like we're
saying science doesn't work, or you shouldn't get in that airplane. Right.
Science works at different at different levels, And even if
it's random at the very very small level, doesn't mean
that on average it's really predictable, right, Like we do
know how basketball's bounce, right, And that's because the randomness
(32:19):
only applies to these tiny little particles, and over the
ten to the thirty or whatever particles in a basketball,
that all averages out to something very very predictable. Wow,
So like random events Canada add up to predictable events?
Is that kind of what you're saying? Yeah, exactly. Like
you can't tell how any individual voter is going to vote,
but if you've done enough polls, you can tell if
(32:40):
you know how the nation is going to vote. Um
at a certain reduction that worked out so well in election.
Maybe that wasn't the best example totally predictable. At the
level of particles, there is randomness, but maybe in the
macro scale things are fairly predictable. But how does that
(33:01):
affect things like free will? Does that mean that, like
my brain just quantum randomness give me some sort of
unpredictability or free will as you might call it, Or
is my brain also very predictable in the long run.
It's a great question, and into this tiny crack and determinism,
you know, saying that at the particle level, things are
(33:22):
truly random. And there's flooded and enormous literature of consciousness
and all sorts of philosophy that that try to connect
free will to quantum randomness, you know, to say that
this is the whole we needed, This is what breaks
determinism and allows for me and my soul and God
and all the and and all the things you want
to cram into your universe. I'm not convinced that quantum
(33:44):
mechanics allows for free will, or for souls or you know,
for all that kind of stuff, but it certainly does
dismantle the deterministic watch like universe that we thought we
had MM. So just because something is random doesn't mean
you have free will. Like it's just random, exactly exactly.
And so to answer the question, you know, is the
(34:05):
universe random or is it chaotic? Turns out it's kind
of both. Right, It's a random at the particle level,
but it's chaotic at the macroscopic level. Right, things do
seem to be fairly deterministic at the macroscopic level, but
then again they're too chaotic to really to really model.
So it's not like you can predict the weather. It's
kind of a progression. Like it's random at the particle level.
(34:26):
It's kind of deterministic at a medium range level, but
then as you get too larger and larger systems, then
it's chaotic and it's practically unpredictable. Yeah, yeah, exactly right.
So any answer you want there's someplace in the universe
is yeah, I just pick a random, random answer and
(34:47):
it will be that. So maybe that's why people answer
with such a such streams of gibberish to our our question,
because because they really deeply understood that the universe was
both random and chaotic. Wow, the wisdom of the some
in the crowd. Exactly, you average over ten random people
and there is some insight there. Exactly. That's the whole
that's the whole problem. Answer is the answer is yes.
(35:10):
So I think it's it's fun to think about that
in so the larger context. You know, like we started
off thinking the universe was crazy, then we started to
get some grips on it. Then we felt like, oh,
maybe the universe is sort of too tight a grip
on us because it seems deterministic, and then we've got
this crack thanks to quantum mechanics. It says it's random.
But I don't really know how comfortable people are with
that crack. You know, to think that the universe doesn't
(35:32):
know what it's going to do at any moment, like
they could do this, it could do that. That's sort
of terrifying. I understand Einstein's fear that Einstein is dislike
or disdain for that um, and that leaves us in
a sort of uncomfortable position. And it might get even crazier, right, Like,
let's say that we build quantum computers and then there's
AI based on quantic computers. That that would be even crazier, right, Yeah,
(35:53):
I'd love to read that science fiction novel that's how
that's how AI develops free will, Right, quantum computers maybe
more than us, that's exactly right. All right, Well, thank
you for joining us. I hope that didn't seem like
a random, random or chaotic discussion. But those are really
(36:14):
fun topics. I think it's super fun to try to
wrap your mind around those things. And you know, one
of the basic questions of physics is not just what
is the world made out of? What are the bits
and pieces? Were like, what are the rules? And are
their rules? And and you know, can we ever understand it?
To me, that's one of the deepest questions of science
and and this goes right to the heart of it.
So if you're a butterfly out there, keep on flatting exactly.
(36:44):
If you still have a question after listening to all
these explanations, please drop us a line. We'd love to
hear from you. You can find us at Facebook, Twitter,
and Instagram at Daniel and Jorge that's one word, or
email us at Feedback at Daniel and Jorge dot com.
M
There's a core idea in science that experiments should be repeatable.
If you do an experiment the same way at different times,
you should get the same result. However, there is a loophole.
There's a loophole in science. Yeah, and that loophole opens
a window into everything we think is true about reality
(00:28):
and the universe and everything. Doo doo doo doo doo
doo doo doo doo doo doo. Welcome to Daniel and
(00:50):
Jorge explain the Universe, in which we try to take
the entire universe and break it into bite sized pieces
so you're gonna enjoy them with your afternoon coffee. I'm alright.
I'm a cartoonist. I draw comics online, and I'm Daniel.
I'm a particle physicist. I spend my days smashing protons
together at the Large Hadron Collider to try to reveal
the secrets of the universe, mostly so that I can
(01:11):
tell them to you in this podcast. Basically only one
of us is qualified to be explaining things to you
on this podcast. That would be the cartoonist business. They're
not qualified usually to be explainers. Mostly we just try
to solve the mysteries of the universe. We don't try
to tell anybody about them, right, Mostly physicists just need explaining,
that's right, that's where the cartoons come in, right, And
(01:33):
spouses also, spouses physicist probably have to do a lot
of explaining. You've got some explaining to do, exactly. Yeah. Um,
So we're here to talk to you about big questions
about the universe. And today's question is a really deep
and basic question, and it's about the very nature of reality.
What is it? Hory? What are we gonna talk about today?
(01:54):
Is the universe random or is it just chaotic? And
what the difference? Or is it run by some super being?
And we're actually just in their simulation. But that's a
whole other episode. That's a whole other podcast. Right today,
just the two sinister options, random or chaotic, you might
feel like, oh, neither of those sound very cozy. I
(02:14):
don't want to live in either of those universes. Well,
the question basically breaks down to is the universe predictable?
Like can you predict what the universe is going to do?
Or is it that nobody can predict what the universe
is going to do? Right? And I think that's why
It's an awesome question for science because for so many
thousands and thousands of years, I think humans probably felt
(02:36):
like the universe around them was totally unpredictable. I mean,
they invented gods for this and for that to try
to describe how the universe was out of their control
and doing things that didn't make sense, as if it
had some you will and agency. Right, and then science
comes along it says, actually, there are rules and you
can discover them. And slowly science starts to creep in
this description of the universe that locks out this agency,
(02:59):
this idea of this personality, and gives you the sense
that maybe the universe follows these rules. Right. So we
went out and as usually, ask people on the street,
do you think the universe is random or chaotic? And
here's what they had to say, that's gonna okay, that's
a that's a thinker right there. I would say truly random.
(03:21):
With randomness comes chaos. You never know what I what
will happen, but there's there's always a probability and a
chance of things, of certain things happening. I'd like to
say random. I'm religious, so I feel like everything happens
for a reason. And yes it is random, but there's
a purpose behind everything. I think it's a mixture of both,
(03:42):
like like it's random, but it can appear chaotic because
of how everything is truly chaotic, because like on a
smaller level, everything is like moving really fast, but at
like a bigger level, we we don't see any of that. Wow,
So what do you think of those answers for I
think they were all over the place. They were actually,
(04:05):
um kind of random. They were random and chaotic. I
feel like I feel like people had no idea what
I was asking them. You know, I feel like people
just I feel like they had no idea what they
were answering. You know, some of those people I remember
recording these interviews, and some of those people, as the
words were coming out of their mouth, I felt like
they surprised them as much as they did me. Like
(04:25):
it was all over the place. Yeah, well, I feel
like some people it's interesting. Some people related to the
question that question to the other question, which is like
does the universe have a purpose, Like do things happen
for a reason or do they is it just like
a random role to die and nobody is really in charge?
Like that's the question, right, like, is somebody in charge
of the universe or is it impossible for anyone to
(04:48):
kind of predict what it's going to do. Yeah, I
think you're right. That does get at the heart of
the question. You know, what's going to happen in the
universe and can we tell and can we influence it? Right?
Is the universe sort of churning on without our ability
to change direction at all in some sort of way
that's been determined since the dawn of time? Or can
we nudge it and push it in one way or
the other? You know, make the calves a win? Or
(05:08):
can you if you jump up and down in front
of your television enough where the Warriors win another NBA championship?
You know, can you influence the world? I think that's
a that's an interesting and deep question. Yeah, that's probably
the one people were actually having in their mind. Yeah,
so maybe let's go back in history, and I like
how you think about this question a lot, Daniel, which
is that you sort of start with early man like
(05:29):
the cavemen and women and women early humans. Um, we're
really just kind of at the mercy of all the
elements and all the animals out there, and the weather
and so they to them, the universe was this crazy,
random and chaotic place, right, Yeah, And it actually touches
on sort of my personal theory of consciousness, which is
that we developed this awareness because we are looking out
(05:51):
into the world for other people or other ideas, are
their intelligences, and we have this hyperactive ability to see agency,
to see intention in something that we don't understand, and
we imagine that there must be a mind behind it.
And so I think for a long time people's view
the world was that it was controlled by other greater minds.
You know, what controls the lightning? Why do some people
(06:12):
die of disease? All this stuff? And then as there
must be like a consciousness that is shooting out these
lightning bolts or making it rain, or you know, making
the sun come out, or killing my baby of some
horrible disease, right, like, there must be. It's hard to
live in this world if you don't have the sense
that there's somebody else in charge. Right There's a lot
(06:32):
of suffering and a lot of pain, and a lot
of unexplained events, and it's nice to think somebody else
out there is taking care of it, or somebody's in
charge of it. But there's a reason, right yeah, that
there's a reason, that there's some design, it's not just random. Um.
But then as history progresses that we were saying earlier,
you know, sigence comes along and says, well, there are
seemed to be some rules, not just like that anything
(06:54):
can happen. You can't have an ostrich here and then
all of a sudden the ostrich is gone. There are
some rules that limit what can happen. If you know
what's happening now, there's a certain set of possibilities for
what can happen in one second, in two seconds. And
you know that's physics, right Well, it's it's started with
like noticing patterns, right Like lightning doesn't just come out
of nowhere, it comes out when there's these dark clouds
(07:16):
in the sky, right yeah, absolutely absolutely, And people started
noticing patterns and started putting those together and then asking themselves,
can I use what I've learned in the past to
predict the future? Right Like, if I have the same
set of events that happened yesterday, am I gonna be
able to tell what's going to happen next week? If
the same thing happens, If I roll a ball down
(07:36):
the hill yesterday and it goes up to a certain speed,
Will the same thing happened tomorrow? Right? Right? Or if
I throw a ball in the air and I know
which direction it's going and how fast it is going,
can I predict where it's gonna land exactly? If I
build a catapult, can I basically aim it right exactly?
And that's how military technology drove science even hundreds of
years ago. Right, Where do I shoot my cannon exactly
(07:58):
to get over that wall? Well, that's kind of where
um Newton came in, right, Isaac Newton, And that's why
they say he kind of gave birth to science, right,
or at least the scientific Revolution. No, I think it
was earlier than that. Newton came along well after folks
like Galileo and and Francis Bacon and those guys. They
really were the first ones to do experiments and to say,
(08:20):
let's see what the rules the universe is following, and
let's see if we can try to deduce them and
use those to predict the outcome of future experiments. They're
really were the first ones to connect the idea of
a scientific universe to the actual experiments they do to
influence those ideas and to predict future results. And I
think that's the key is that here we've developed a
system science which cannot only explain what we've seen before,
(08:42):
but can predict the future. And you are about to
fire a cannonball at your enemy, you want to know
where is that ball going to fly? And it's incredible
that physics can do that. It can literally predict the
future if you know enough about the situation right right,
It's kind of like Google Maps. Now I can totally
tell if you're going to be late to the meeting
or not, or to a podcast recording they're gonna They're like, like,
(09:04):
how long will they need to get home? They're like,
they're gonna be late. It's not always a hard problem though. Joe.
For example, it says if person equals Jorge, then late
equals true every time, every time. A lot of data,
and some of these things are simple, but some of
these things are complicated, and it's incredible to witness as
(09:27):
physics sort of builds confidence and science develops our ability
to predict you know, chemical reactions and biological functioning, all
sorts of things, and then it gives this creeping sense
of is there anything that can escape science, Right, Can
science predict everything? Like, if you knew enough about the world,
could you break it all down to cannonballs to predict
(09:48):
where all those cannonballs are going to fly and then
tell exactly what's going to happen. Yeah, And it's it's
like kind of like if you know that force equals
mass science acceleration, like Needton figured out, um, then you
can predict things like cannonballs and catapults and and and
you could possibly predict like how a room full of
particles move, right, Yeah, possibly you can extend that to
(10:10):
can you predict how, um the whole world works? Yeah,
what it's going to do and what people are going
to do? Extrapolate to the whole universe, right, I mean,
and that's the principle of determinism. It says, Look, if
things follow rules, and the future is dependent only two things,
one the rules and two the things that are happening
now the current state. Right, given that if you know
(10:32):
exactly where things are, imagine the whole universe is just
a bunch of tiny cannonballs, and you know the rules
of those cannonballs, and you know the position and direction
of motion of all those cannonballs. Then in principle, given
a super powerful universe sized computer, you should be able
to predict the future one to five ten seconds into
the future, a thousand seconds into the future, like every
single molecule, atoms of atomic particle. You should be able
(10:55):
if it follows rules, you should be able to kind
of track where it's going to go if you tell
you based on where things are now, what's going to happen? Exactly.
It's kind of like this idea of a clock, right,
is the universe giant clock just kind of clicking along
or is there some kind of magic inside of it
that makes it unpredictable? Right exactly? And the idea of
(11:17):
the universe just being a huge clock, is both exciting
and terrifying. Right. It's exciting because like, wow, can you
imagine we could understand the universe that well, that we
could predict the future, think about what we could do, right,
But it's terrifying because it's sort of like you're trapped
in this science cage where you have no influence over
the world and everything you do and know and say,
and that joke you're going to make in that fart
(11:38):
you're gonna let slip are all predictable? Right, all those
things are predictable. That's scary. It makes you feel like
you are part of that watch and you're just clicking
along because of the the you're reacting to things around
you and your initial conditions, and so that's terrifying. And
I think we have kind of in anate sense of
like rejecting this idea that we're trapped, right we everyone
(11:58):
wants to feel like they have free will, like everyone
wants to know that they have a choice, right. Well,
I guess so my kids don't feel that way, you know,
like why did you hit your sister? Well she hit me,
you know, like, well, so what you have no free will?
Like you're completely determined by her behavior. Um. I have
that argument with my kids so many times. I'm always
thinking about the philosophical echoes of that. Um. Um, My
(12:20):
kids are always rebelling. They're like, we want free will,
don't tell us what to do, but they want you
to follow rules. They're like, you promised daddy we could
have ice cream, right, and so therefore you have to
there's no more decision to be made. Kids are so
unfair there, philosophically inconsistent. I think it's really the problem
with kids Yeah, they're cute, but if they just read
(12:43):
some more nice you know, and some some carl and
some paper or whatever, they would be easier to be around. Yeah,
forget those picture books. Let's introduce let's predict the universe.
(13:07):
I think there's something fascinating about the deterministic view of
the universe. But probably people out there thinking, Okay, maybe
in theory you could predict the whole universe, but in
practice that's impossible. I mean, you don't have a universe
sized computer to break the whole universe, and even to
predict like you know, a person is a huge number
of articles, and so to do that calculation just seems impractical, right, right,
(13:29):
It's practically impossible. But I think people reveled just to
the idea of it, right, Like, are my thoughts my
thoughts or just something that I'm programmed and that I
will inevitably have and do. Yeah, and that's a really
deep question. And so um, we started out with prehistoric
man feeling like the universe is full of random of
not random, but unexplained agency and intelligence all the way
(13:52):
to like now, scientific physical determinism says, actually the universe
just clicks along like a watch, right, and there's no
free will. So let's take one step back from that,
and that's chaos. That says, well, maybe the universe is deterministic, sure,
but that doesn't mean it's necessarily practical for you to
predict it because the way things play out is really
(14:13):
sensitive to exactly how things started. Well, I think I
think some people who responded to their question maybe weren't
sure about the difference, right, Like, what's the difference between
something being chaotic and something being random? Right? And so
let's drill into that. So let's take, for an example,
the roll of a dice. Right, people think of rolling
dice is random, but actually it's chaotic, meaning that it's
(14:35):
hard to predict, but it is deterministic. What do you
mean if you knew exactly how I threw the dice,
like exactly the direction and the spin and all the
molecules of the air, then you could treat the molec
little cannonballs, little particles, and you could model how it rolls,
and you could, in theory, predict exactly how the dice
rolled every time, meaning like if I if i'm if
(14:56):
I'm seeing footage of you throwing to die, and like
like I pause the video just as to die leave
your hands, then I could you know know where they are,
I know which direction are going, how fast are going.
I could run some kind of computer simulation to like
follow the die and predict what they're going to do
when they bounce off the table on roll around, I
(15:17):
could potentially predict what the die are going to show.
That's right, because we're saying that the universe in that
case is deterministic, and so you should be able to
predict the future given enough information about the setup. Right now,
that's a hard problem, and that's why we use dies, right,
because it's really difficult, and nobody can practically like bring
a mini computer into Las Vegas and use that to
(15:38):
predict who's going to win it craps, right though, in theory,
In theory, you could if the universe was deterministic but
very sensitive to exactly how somebody's rolling the dice. Right
when you throw the dice of craps, if you flip
it this way or that way, then it's going to
bounce slightly differently, and how it's going to hit that
you know, the felt on the table. It's all very
very sensitive and a very small change how you throw
(16:00):
it can result in a totally different number. That's what
we mean by chaos. It means that it's like that
the butterfly effect, right, like the idea that if you
butterfly flaps its wing here, it's going to have a
huge effect, maybe potentially on the weather and on the
other side of the world. Right, it's like a very
sensitive system. That's right. The weather is a great example
(16:20):
because we understand all the processes of weather. I mean,
it's hot air, it's cold air, it's water. We know
that stuff. It's pretty simple chemistry. But altogether, an entire
planet is really difficult to describe because it's huge and
it's really sensitive. Like, as you say, a butterfly flapping
its wings in China could change the way this air flows,
which could change the way that air flows, which bounces
(16:41):
off this building, which turns into a rainstorm, which collides
with this cloud and causes a hurricane. Right, it's not
true that every time a butterfly flaps its wings you
get a hurricane. But sometimes so. Weather is chaotic, but
it's not random, is that what you're saying? That ran like,
if we could keep track of every single butterfly in
the world flapping its wing. We would be able to
(17:02):
predict the weather if we had a giant supercomputer the
size of the Solar System. But since we don't, then
weather it seems random, but actually it's chaotic exactly, And
that's exactly what scientists are trying to do. They're building
bigger and bigger and faster computers to try to simulate
more and more of the Earth's atmosphere to get better
and better predictions of weather. In fact, I think like
(17:24):
all the top ten supercomputers in the world are devoted
to that problem, like modeling the weather, because it's important.
But you're exactly right, it's actually chaotic, meaning it's deterministic
but really sensitive to exactly how it started. But it
seems random because it's it's too difficult for us to calculate.
In principle, we should be able to, but we can't.
Another example is flipping a coin. Right, based on how
(17:46):
you flip the coin, you should be able to model
how it spins through the air and how it bounces
off air molecule and how it hits the ground and
where it lands. But it's a difficult problem. So we
can use it to model randomness to say it's kind
of like randomness. Really it's just chaotic though. But then
if I flip the coin a hundred times, most likely
half of those times will be head and half of
(18:07):
those times will be tails. Right, So where does that
fit into chaos theory? Like why is it predictable on
a statistical basis? Okay, so that's fascinating. That's an emergent phenomenon. Right.
That says if you understand the tiny little local laws
of physics, like the laws of how the particles inside
the coin move, you should be able to predict some
larger effect. And it's true, there is a simple or
(18:30):
description of that larger effect, right, if you understand how
these things work. Um, So physics works on these layers. Right.
You can either understand it a very low layer and
try to model it all the way up to a
higher layer, or you can just try to get an
understanding of at a higher layer, just the same way.
You could say, well, I can understand the way cannonball
flies by modeling all the particles inside of it, or
(18:51):
you could just use F equals m A, which treats
the whole cannonball like one particle. If that's just a
question of at what layer you're modeling something, right, Okay,
so a coin is chaotic but not actually random, but
not actually random. Yet, if the universe is deterministic, then
a coin is chaotic but not actually random. Yeah, okay,
got it, got it. But then it's the question of
(19:13):
that's the really the nugget of the question is is
the universe deterministic? Um, you know, if you have a
particle or a billiard ball or cannonball or whatever, and
you understand direction it's going, can you predict its future
out into infinity? Right? Right? You tell exactly what's going
to happen. But there's so many factors leading up to
me tossing the coin that it's so unpredictable that it's
(19:35):
it's it feels random, that's right. And so we have
to separate between what's practical and what's in theory possible.
Anything that's chaotic. We're saying, in theory, if you knew enough,
you could predict it, right, whereas but in practice that
we can't. So it's it's it's can't. So it seems random.
Random number generators and computers when they try to come
(19:56):
up with a random number, it's not really random. You're
saying it's just an algorithm. That's very that's chaotic. That's right.
Computers by construction are deterministic, right, We've built them to
be deterministic. Every time you run a program, it should
give you the same answer if you give it the
same input. Right. That's there's no way for computer to
do anything but that. It's like a series of logic gates.
(20:16):
And you know, how it's implemented is not important, but
you know it's a system for doing deterministic calculations. That's
what a computer is. So it's impossible for computer to
be truly random. All the random number generators in your
favorite Python code are actually pseudo random number generators. They're
just chaotic. They take a seed a number to start from,
and then they spin off of that and generate a
(20:38):
sequence of numbers. But if you give them the same
seed twice, they'll generate the same sequence of numbers twice. Wow.
So like if you're playing a video game and you're
inside of a virtual world, that world is totally determinating.
It's being crunched on by a logical computer. Exactly. You
do the same move every time. You'll kill that boss
character every single time, and not even in silivating games
(20:59):
like you know, like punch Out where the guy is
totally predictable, but even the more complicated ones. You know, Um,
if you're in the same world and you do the
same thing, the same thing should happen, because computers are
not capable of true randomness. Before we keep going, let's
take a short break. So the question is is our
(21:27):
universe like a computer simulation? Right? Like the question is
is is our universe also being crunched by a logical
computer that can't be random? That's right? And for a
long time people thought the universe was deterministic. I mean,
we were able to predict the outcome of every experiment. Um,
things were going along really well. And then of course
(21:47):
and throw a spaceship and landed on the moon. That's
pretty crazy, right, Yeah, that well that's pretty risky, but yeah,
um that's pretty amazing. You have to certainly have confidence
in our ability to predict the future if you're gonna
get into that can involve gets shot out into space. Right. Um, Well,
I remember in grad schlos in this classic it's called
linear dynamical systems. But I remember in class, this guy
(22:08):
was so the professor was so cocky. He's like, of
while the technologies that contributed to putting a man on
the moon, this is the one that made it happen
linear algebra. Kind of had this linear algebra equation, we
would not be able to put a man in And
so that that's how powerful this idea is, right, Like,
if you can predict efreequels in a you can put
a man on the moon. Yeah. No, it's exactly right,
(22:29):
And it's given us great power over our environment. I mean,
everything that we have is because we have mastered a
lot of the laws of our environment and use them
and bent them to our will to improve our lives. Right,
So it certainly works, and we rely on every day,
every time you get into a car or an airplane,
you rely on it working the same way it did yesterday, right, right, right,
So that's that's a relief. Um. But it was about
(22:50):
a hundred years ago when people started seeing things that
they couldn't explain, and it was quantum mechanics that told
us that maybe the universe is not deterministic. Maybe these
little particles don't follow the same rules that like billiard
balls and basketballs and larger objects follow, and maybe they're
not even deterministic. Meaning if you do the same experiment
(23:11):
twice with tiny particles, you could get different outcomes even
if you do it exactly the same way. Well, and
this all came about when people started noticing that like
light and things had a minimum size, right, Like light
doesn't come in infinitely small bits of light, Like there's
chunks of light, that's right. Yeah, Einstein was looking at
(23:32):
some experiments that didn't quite make sense, and the only
way he could explain them was if light came in
little packets. And that's what quantum means. Quantum means a
unit or a packet, and so he suggested that maybe
light comes in these little packets. But then it had
all these far reaching consequences, you know, um about light
going through mirrors and through prisms, and the way people
(23:52):
could understand that was only if there were various probabilities
for things to happen. And it began this whole revolution
of quantum mechanics, which then Einstein tried to put the
brakes on, right. He was like, way, a hold on
a second, guys, this is crazy talk. There's no way
the universe works this way, meaning like um, this idea
of quantum stuff only made sense if the universe work
based on probabilities, not like deterministically. You know, you have
(24:16):
to describe things with wave functions, and things aren't really
like point particles are kind of fuzzy things. That's exactly
the point is that there's this fuzziness in the universe
and quantum mechanics because there's these minimum sized objects and
the way they interfere with each other and the way
the calculations happen. Quantum mechanics predicts that the universe is
fundamentally random, and it means that, for example, you have
(24:37):
an electron, you don't know exactly where it is. There's
a probability distribution that says, most likely it's here, maybe
it's there, maybe it's somewhere else. Is it that we
can't is it like a randomness, like we can't uh
know where it is, or that there's this trade off
between like momentum and position. Right, that's exactly the right question,
and that's exactly what people are asking. They looked at
(25:00):
these equations and they said, well, is it that we
can't predict where the electron is, like it's totally impossible
to predict, or is it that we just don't know
where it is that we haven't figured out how to
get that information, right. Does the information not exist or
do we just not have it? And so Einstein is
the one who said there must be some hidden variable.
There must be something that's that these particles are carrying,
(25:22):
some piece of information that determines exactly what's going to
happen to them, but we just don't know what it is.
To him, it was crazy to think that you could
shoot an electron into an experiment twice and get two
different answers. But that's appeared. What appeared to happen. People
set up these careful experiments where you would shoot a
photon one at a time. You would shoot photons into
(25:43):
an experiment, and every photon would do something different, and
then as you would accumulate a bunch of photons, it
would add up to give you a distribution that made
sense to you. Just the same way when you flip
a coin, you get heads, you get tails, you get heads,
you get tails. It seems random, but eventually it builds
up to fifty fifty. Right. Quantum mechanics tells us all
we can do is predict the eventual distribution. We can say,
(26:06):
if you measure a thousand electrons, some of them will
go here and some of them will go there. It
says you can't predict any individual one. All you can
predict is the distribution of outcomes. So Eisland was like,
maybe a photon is kind of like the coin we
were talking about before, Like maybe it seems random to us,
but really it's just kind of this chain of of
little local events that actually make it predictable. That's right,
(26:30):
if we knew all that information inside, Like maybe it
just looks fuzzy to us that we can't tell where
it is, but inside that particle really actually knows where
it is. It's exactly right. That's what he wanted to believe, right,
That's what he wanted to believe. And you've got to
sympathize with the guy. Right, it's hard to imagine that
the universe would not be deterministic. I mean, we spent
hundreds of years building up our confidence in science and
(26:51):
his physics, especially as being able to predict the future,
and and just of saying basically, the universe follows rules. Right,
So now all of a sudden you're telling us what
there's like dice in there is there some randomness? Like
every time you shoot an electron to your experiment, somebody
or something or the universe is making a like a
random decision about where it's going to go. It seems crazy,
So you're absolutely right. And he suggested that a simpler
(27:13):
explanation is that they're carrying along another piece of information
that we just don't have access to or can't measure,
or didn't measure, and that that's actually determining in a
totally predictable way what's going to happen to each particle.
That was his solution to the problem. Well, he famously
said God doesn't play dice, right, He's famously quoted as
saying that, I'm not sure he actually did, but it's
(27:34):
really but it's a pretty good summary of what he believed.
Fake news, well, like a lot of fake news is
a cronel of truth in it. Um. He certainly wanted
to believe in a deterministic universe and it made sense
to him. And you know what, it makes sense to me.
I mean the idea that there's like a tor random
number generator somewhere in the universe that's making a decision
(27:57):
every time you're shoot an electron into something. It's doesn't
make any sense. To me intuitively. You know, not that
the universe has to make sense to me intuitively, but
it doesn't. So you're saying the quantum mechanics says that
there is a randomness in things, And so where is
that randomness actually in like the position of particles in
(28:17):
the verse of the velocity um, in their like very being,
in their energy level? What where is this randomness of everything? Well,
there's randomness at every level. I mean there's a randomness
between every time you look at something. So say, for example,
you measure an electron, you see it's a certain place,
then you look away, right, because you can't monitor an
(28:38):
electron every moment or every nanosecond ven you look away,
what is the electron do between when you last saw
it and when you'll next see it? Meaning like, if
I know where it is and how fast it's going,
and then I look away and I look again, is
it going to be where I think it's going to be? Yes, exactly.
And so every every moment of an electron or a
particle's life is determined by quantum mechanics, which says there's
(29:01):
a probability distribution. It's not like the electron is doing
something behind your back. It's got one particular path that
you're just not aware of behind your back, and you
just don't know it. It doesn't have a specific path.
It's not like it goes from a to via a
particular path. It has a probability of different ways to
get there, and if you don't look, then it's sort
(29:23):
of doing all of them at once. They all have
different probabilities, and those probabilities are the things determined by
the laws of physics. So there's still are laws. Physics
still does tell the universe how to run. It's just
that those laws are probabilistic. It says, look, Mr Electron,
instead of telling you exactly where you're gonna go, I'm
gonna say you have a seventy percent chance of doing
this and the thirty percent chance of doing that. So
(29:44):
that's where the fuzziness and the randomness comes in. It's
not that it like it looks fuzzy, it's just that
it's just hard to predict where it's going to be.
It's impossible. You know all this information, it's impossible. It's
impossible to predict the future. Impossible exactly, you can predict
the various likelihood of the So the likelihood of that
at the particle level, but you can't say what one
particle is going to do. Now, Einstein said, that's crazy, right,
(30:07):
there's no way that's true. There must be a way
to predict it must be there some piece of information there.
And then some guys came up with an experiment. They
came up with this crazy experiment. It's based on an
idea called Bell's inequality. To test this theory, they said,
let's see if the universe is really random, or if
there's some hidden piece of information that's actually secretly determining things,
(30:28):
like let's see if if I really can't predict for
that electron is going to go, or if it's actually
like the electron knows it just won't tell us. Yeah, right, exactly. Um.
And so they set up this cool experiment where they
took a particle and they had to shoot out two
particles in opposite directions. And those particles are therefore connected
because they have to conserve momentum, they have to conserve
(30:50):
energy and have to conserve spin. And so if you
know something about one particle, that you know something about
the other particles, but both particles have equal probability to
be like spin up or spin down own, or point
this way a point the other way, but you know
something about the combination of the two. And so they
came up with this really ingenious experiment to measure how
often you saw one spin up and one's been down,
(31:11):
for example, And based on the outcome of that, you
could tell whether there was a secret, hidden um piece
of information that was controlling both particles, or whether they
were both truly random. And the experiments are conclusive, and
it's been done a zillion times, and the experiment tells
us that the universe at its core really is random.
That's making a random decision every time you look at
(31:33):
these particles. So beyond the shadow of a doubt, we
know that the universe is random. The universe is random. Absolutely.
There's no no escape clause, there's no if hands or
but there's no asteris no loopholes. The universe at the
part of the level is really random. Now, you said
something really interesting earlier. You know, even if the universe
(31:55):
is random at the lowest level, that doesn't necessarily mean
that it's a random at other levels. Right, Like we
still got to the moon. Right, It's not like we're
saying science doesn't work, or you shouldn't get in that airplane. Right.
Science works at different at different levels, And even if
it's random at the very very small level, doesn't mean
that on average it's really predictable, right, Like we do
know how basketball's bounce, right, And that's because the randomness
(32:19):
only applies to these tiny little particles, and over the
ten to the thirty or whatever particles in a basketball,
that all averages out to something very very predictable. Wow,
So like random events Canada add up to predictable events?
Is that kind of what you're saying? Yeah, exactly. Like
you can't tell how any individual voter is going to vote,
but if you've done enough polls, you can tell if
(32:40):
you know how the nation is going to vote. Um
at a certain reduction that worked out so well in election.
Maybe that wasn't the best example totally predictable. At the
level of particles, there is randomness, but maybe in the
macro scale things are fairly predictable. But how does that
(33:01):
affect things like free will? Does that mean that, like
my brain just quantum randomness give me some sort of
unpredictability or free will as you might call it, Or
is my brain also very predictable in the long run.
It's a great question, and into this tiny crack and determinism,
you know, saying that at the particle level, things are
(33:22):
truly random. And there's flooded and enormous literature of consciousness
and all sorts of philosophy that that try to connect
free will to quantum randomness, you know, to say that
this is the whole we needed, This is what breaks
determinism and allows for me and my soul and God
and all the and and all the things you want
to cram into your universe. I'm not convinced that quantum
(33:44):
mechanics allows for free will, or for souls or you know,
for all that kind of stuff, but it certainly does
dismantle the deterministic watch like universe that we thought we
had MM. So just because something is random doesn't mean
you have free will. Like it's just random, exactly exactly.
And so to answer the question, you know, is the
(34:05):
universe random or is it chaotic? Turns out it's kind
of both. Right, It's a random at the particle level,
but it's chaotic at the macroscopic level. Right, things do
seem to be fairly deterministic at the macroscopic level, but
then again they're too chaotic to really to really model.
So it's not like you can predict the weather. It's
kind of a progression. Like it's random at the particle level.
(34:26):
It's kind of deterministic at a medium range level, but
then as you get too larger and larger systems, then
it's chaotic and it's practically unpredictable. Yeah, yeah, exactly right.
So any answer you want there's someplace in the universe
is yeah, I just pick a random, random answer and
(34:47):
it will be that. So maybe that's why people answer
with such a such streams of gibberish to our our question,
because because they really deeply understood that the universe was
both random and chaotic. Wow, the wisdom of the some
in the crowd. Exactly, you average over ten random people
and there is some insight there. Exactly. That's the whole
that's the whole problem. Answer is the answer is yes.
(35:10):
So I think it's it's fun to think about that
in so the larger context. You know, like we started
off thinking the universe was crazy, then we started to
get some grips on it. Then we felt like, oh,
maybe the universe is sort of too tight a grip
on us because it seems deterministic, and then we've got
this crack thanks to quantum mechanics. It says it's random.
But I don't really know how comfortable people are with
that crack. You know, to think that the universe doesn't
(35:32):
know what it's going to do at any moment, like
they could do this, it could do that. That's sort
of terrifying. I understand Einstein's fear that Einstein is dislike
or disdain for that um, and that leaves us in
a sort of uncomfortable position. And it might get even crazier, right, Like,
let's say that we build quantum computers and then there's
AI based on quantic computers. That that would be even crazier, right, Yeah,
(35:53):
I'd love to read that science fiction novel that's how
that's how AI develops free will, Right, quantum computers maybe
more than us, that's exactly right. All right, Well, thank
you for joining us. I hope that didn't seem like
a random, random or chaotic discussion. But those are really
(36:14):
fun topics. I think it's super fun to try to
wrap your mind around those things. And you know, one
of the basic questions of physics is not just what
is the world made out of? What are the bits
and pieces? Were like, what are the rules? And are
their rules? And and you know, can we ever understand it?
To me, that's one of the deepest questions of science
and and this goes right to the heart of it.
So if you're a butterfly out there, keep on flatting exactly.
(36:44):
If you still have a question after listening to all
these explanations, please drop us a line. We'd love to
hear from you. You can find us at Facebook, Twitter,
and Instagram at Daniel and Jorge that's one word, or
email us at Feedback at Daniel and Jorge dot com.
M
Hosts And Creators
Daniel Whiteson
Kelly Weinersmith
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