Can brains spontaneously form in space?

Daniel and Jorge talk about the chance that you could be a brain floating in space.

Learn more about your ad-choices at https://www.iheartpodcastnetwork.com

See omnystudio.com/listener for privacy information.

Episode Transcript

Speaker 1 (00:08):
Hey, Orgey, did you ever think about the odds of
you existing? My existence is pretty odd. So well, I'm
sure that you exist right now, but you know, go
back a hundred years. What are the chances that everything
would align to make or hey, oh man, I I

(00:28):
think I'm pretty special, so probably pretty low. Exactly, so
many things had to happen in just the right way
for you to be here, right It seems astronomical that
I would be here, Yes, and yet you are here.
So sometimes unlikely things actually do happen. Maybe a hundred
years from now, you'll be listening to David and Juan

(00:50):
explain the universe instead. I am more Hammond cartoonists and
the creator of PhD comics. Hi, I'm Daniel. I'm a

(01:12):
particle physicist, and I like to think about really unlikely events.
Oh yeah, like us getting a podcast. Yeah, or two
protons colliding to make a Higgs boson, which happens like
one in a trillion collisions. But those are important, right,
Like when it happens, it's a pretty big deal. Exactly
when it happens, it's exciting. It teaches us something about

(01:33):
the universe, and also thinking about these rare things, thinking
about the extremely unlikely events tells us something about like
the nature of the universe, what's possible and what's actually
zero percent possible? Does it also sort of teach a
little bit about perseverance, like if you try enough times,
you should eventually be able to do anything. Yeah, And

(01:54):
it helps to persevere because our collider operates at like
millions of times a second, so you don't have to
wait that long to get a trillion tries. Are you
saying that your collider misses several million times a second? No,
it makes collisions every time. It's just those collisions are
usually boring. Not much exciting happens on your average collision

(02:14):
at the LHC. I see, so it basically it has
like a zero point zero zero zero zero zero zero
one RBI. Yeah, exactly. We actually throw away most of
the data from the large age on collider because it's boring.
But anyways, welcome to our Unlikely podcast. Daniel and Jorge
Explain the Universe, a collection of I Heart Radio in
which we focus on that tiny little bit of the

(02:37):
universe that's amazing, that's exciting, that's wondrous, that's confusing. We
talk about all the things that are out there in
the universe that you want to fit into your brain.
You'd like to understand how neutron stars work, you want
to know how the galaxy formed. You want to understand
it from particles all the way up to superclusters of galaxies.
So you've come to the right place because we take

(02:57):
the entire universe and explain all of it to you.
Because it is a pretty huge universe. I mean, it's fast,
and it's full of stuff in it and energy, and
it seems like there are amazing things happening and existing
all over the place, and makes you wonder how likely
it is for them to be there or not. Yeah, exactly,
And we can't go to all those places, and we

(03:18):
can't even see all of those places, so sometimes we're
limited to like mental explorations, to take journeys in our
mind and wonder, like, is it possible that somewhere out
there there's another planet with similar kinds of people on it,
listening to a even funnier podcast, and wonder what their
names are? But yeah, it's sort of like taking a
mental vacation, except you actually do it for work. It's

(03:40):
like you take a mental work trip. Yeah, it's called
the thought experiment. How do you expense that in your accounting? Unfortunately,
they're mostly free, right, there's no plane tickets, there's no
risk of catching a virus. It's a great way to
do some work. Can you fly first class? Though? Is
that allowed in your government grant? They have to say
it uncomfortably while you have your thought experiments. Oh, that's

(04:00):
the best part is that it looks exactly like you're
taking a nap. So if I remember caught by my
department chair napping on my couch, I'll just say no, No,
I was doing thought experiments. I was working. I was
having physics dreams. I guess that counts rights work for you. No, No,
it's a real privilege to get to like think about
the nature of the universe for your job. So I

(04:21):
definitely religion enjoy that. Well, it is a crazy universe,
which I guess requires some crazy thinking to understand it,
explore it, and come up with interesting explanations for it. Absolutely,
we like to do these crazy thought experiments. And you know,
I was thinking about the kinds of things we think
about happening in the universe, crazy shock waves and all
sorts of bizarre stuff. And I got an email from

(04:43):
a listener just yesterday who asked me this funny related question.
This is Dev Candlewall, and he says, what do you
think is the scariest thought in the universe? So I
was wondering what you thought about that whorehead the scariest
thought in the universe? Ah, like the one that would
shock people the most. Yeah, exactly what did you reply?

(05:06):
I said, I would ask Korge next time we record
a podcast. Let's see, let's see that the universe will
run out of bananas, a zero banana universe. I don't
think that's possible quantum mechanically. Well, there you have it.
I can sleep easier at night, or I can take
naps much more comfortably now, all right, So there you go, Dev,
you don't have to worry about scary universes. Quantum mechanics

(05:27):
protects the number of bananas in the universe. So we
got another interesting question from a listener, this time about
a pretty crazy thought experiment. Yeah, that's right. We're always
getting questions from listeners who are thinking themselves about crazy
stuff in the universe and wanted to hear us chat
about it. So here's a really fun question we got
from Roselle Santos hiding and I have a question about

(05:51):
Boltzmann brains. I read that there are hypothetical self aware
disembodied brings floating around in the universe. But why would
serious physicists hype the size about disembodied breeds floating around
in the universe. It sounds both shocking and absurd to
me that I'm excited to know more about it. I
love the pod. Thank you. Wow, that was a pretty

(06:14):
interesting question. There so much the pokemon a physicists, I know.
I love that she assumes that there are serious physicists
out there. Yeah, there's a difference. Like there's two kinds, right,
There's the clowney kind, and then there's the serious kind.
You know, the kind of words both ties and the
kinds of were both ties with colors in it, right,
the kind of do actual work and the kind of

(06:36):
just do podcast with cartoonists. It's now, those are the
seriously cool physicists, right. That's why I'm wearing my clown
shoes over here. But thank you roself for sending in
this question, and thank you to all our listeners who
send those questions. So it's cool to get ideas from you. Absolutely,
and this sounds like a ridiculous and absurd idea, but

(06:57):
it's actually a very useful and powerful tool in cosmology.
Thinking about this question about brains forming in space, I
see it's a serious question. It's a serious question about
a silly idea. That's my favorite kind. So to be
on the program, we'll be asking the question can a

(07:20):
brain spontaneously form out in space? What? What does this
even mean? Like a brain just suddenly appears completely out
of the blue. Well, you can't just like violate the
laws of physics and just like appear out of nothing.
You have to find a way in the laws of
physics for a brain to like self assemble out of

(07:41):
the stuff that already exists, or for particles to fluctuate
out of the vacuum and come together into a brain.
I agree with Rosel, this sounds both shocking and absurd
to me. How can you be serious about this? You
can quantify it, right, you can lay down exactly the
probability for this to happen or not happen. All right,
So the idea is that as the kind it's called
the Boltzman brain. Yeah, it's the Boltsman brain. Is named

(08:03):
after Ludwig Boltzman. Who first thought about weird probabilities, because
he was one of the pioneers of statistical mechanics, which
thought about entropy in terms of like microscopic little particles.
So it's not his brain. It's like he came up
with this idea of hypothetical brain. He actually didn't come
up with this specific idea of Folks later realized that

(08:24):
this is an outcome of some of his arguments. But
yet all goes back to the question of, like, what
universe do we live in? Do we understand it is
the universe that we're looking at, one that we expect
to see, how unlikely is it? And if the universe
is unlikely, does that mean that we're totally wrong about
what we're actually looking at. Wow, some pretty big ideas
there to be fit into a little brain. So I

(08:47):
guess the basic concept is that you know, the universe
is crazy. There are things popping into existence all the
time and forming and bumping into each other, and so
what are the chances that suddenly things would just form
a brain out and space? Right? That's right, like for
a long time, for momentarily or does it matter, Yeah,
it would be momentarily. And then the question of you know.
How long it survived depends on you know it. Does

(09:09):
it also fluctuate in new existence with the body around
it and with a planet around it? Or is it
just like literally a brain out in space, which, as
you suspect, wouldn't last very long. He would turn into
brainsical pretty quickly there. Unless it forms in the middle
of a sun. That would be tragic, roasted toasted brain.
Maybe that's the scariest thought in the universe. Oh man,

(09:30):
that your brain, like who exists for a second in
the sun before you do? And that start it's pretty bright. Actually,
well it's a pretty crazy question, pretty serious but crazy question.
And we were wondering, as usual, how many people out
there had heard of this idea, this hypothetical brain, or
even think that it is likely. So, as usual, Daniel

(09:50):
went out there into the internet to ask people what
are the chances that a brain would spontaneously form in space?
And so, as usual will I'm deeply, deeply grateful to
those of you who volunteered to answer random questions and
lend your unprepared thoughts to the podcast. If you'd like
to volunteer in the future, please I encourage you. You

(10:12):
get to hear your own voice on the podcast, and
trust me, it's fun. So right to me two questions
at Daniel and Jorge dot com. There's a whole protocol, right,
like you ask people to not read the question, but
start recording, and then you ask them to read the
question right, and then they have to answer yeah, exactly,
no googling. I'm trying to capture the same energy and
spirit that we had when I was just walking around

(10:33):
campus at you see ir run before the world sort
of shut down and those folks didn't get like a
chance to look on their phones to go think about
it or ask their favorite physicists. Because the goal here
is just to get a sense for like, hey, what
do people know? What do people understand already? Because you know,
we're trying to teach this stuff to you guys out there,
and we want to get a sense for what level
to pitch it at the people run away from you.

(10:53):
Also on internet, do they call campus police? Also, they
don't give me as many weird looks on the internet
as they did in real life, which is kind of
surprising that you know, of they're probably rolling their eyes,
you never know. Well, I hope they have fun with it.
At least. But anyways, think about it for a second.
Do you think a brain could spontaneously form out in space?

(11:15):
Here's what people have to say. That's a really interesting question.
I think I've heard of it before. It's maybe the
Boltzmann brain. My understanding is that if the universe is infinite,
then such a brain has to form somewhere at some time.
But I still find that really hard to believe. I

(11:37):
don't know how many random atsoms if there's like an
infinite supply, then well, it also depends on what type
of brain. So I have had something um less complex,
like the brain of an aunt. I'm guessing maybe one
in ten to the five, but it was more sophisticated.

(12:00):
It like a human rain. Maybe you wanted into the fifty. Um.
I don't have a real basis for these gisses, so
I think that the chances of a brain spontaneously forming
from random atoms is not that low. I could totally
see it happening because atoms are the building blocks for matter.

(12:22):
So um, if it didn't happen already, I could definitely
see it happening in the future. Oh my god. Uh well,
I would never say that absolutely, there's no chance for
that to happen. But even if it would happen, where

(12:45):
would this form and how long would last? Um? But
it's interesting. Chances are I don't think it matters, uh
to calculate the chances, but for sure there are some chances.

(13:07):
I finally got a question I know the answer to.
I just finished reading Brian Green's Until the End of Time,
and I know that a Boltzman brain could form within
ten to the ten to something years, which is at
least less than the amount of time left in the universe.
So people are pretty skeptical. Well, I was surprised a

(13:30):
lot of people knew what you were talking about. They're like, oh, yeah,
the Boltzman brain. Of course, who doesn't know about the
Boltzman brain. Well, we got smart, well educated listeners, and
you know, Boltzman brain is a thing that's been sort
of bouncing around for quite a few decades. And people
seem pretty open to the idea, right, Like they didn't
think like, no way, Yeah, they're more open to it

(13:50):
than you or when you heard about it a minute ago.
I am maybe odd about these odds. All right, So
it's a pretty interesting idea. So tell us an, you know,
what are the chances that a brain would spontaneously appear,
and how would it happen? Yeah, well, the odds are
very very very very very very small, but technically not zero.

(14:12):
You know, there is the possibility for particles in space
to sort of bump into each other and assemble into atoms,
and those atoms could assemble into molecules, which could assemble
into cells, which could assemble into a brain. Like, there's
nothing in the laws of physics actually preventing that from happening,
which means the probability is non zero, but of course

(14:35):
very unlikely. Do you need the atoms to have been
formed already, Like do you need carbon atoms or are
you talking about particles at the like the cork level,
Like corks suddenly become you know, protons and neutrons just
the right you know, ratio, and then those become carbon
and potassium and oxygen and and suddenly everything like just
poofs into existence. Or do you do you mean like assembled, Well,

(14:56):
I guess you could actually just poof into existence. That
been less likely, right, all that stuff to just like
fluctuate out of the vacuum instantaneously. I think it's more
likely for you to fluctuate the essential components out of
the vacuum, you know, for a photon to turn into
a pair of quarks and anti quark, or for photon
to turn into electron oppositron, and for those particles to

(15:19):
assemble into atoms and then molecules and then cells. So
I think that's probably more likely than the actual massive
quantum fluctuation of a whole brain. But don't you need
like a supernova sometimes to assemble some of these particles
or do me like they maybe come into existence with
that kind of energy. Yeah, well, you can build these
things out of anything. Typically they are made, you know,

(15:42):
in the cores of suns or in supernovas or neutron
star collisions. But that's not the only way you can
make them, right. We can also make them here on
Earth in collisions of particles. So yeah, you can make
them in other ways. There's no law of physics requiring
you to have a supernova in order to make uranium
or phosphorus or whatever it is. So like you're saying,
like it's not just a brain, then it could be

(16:03):
anything like a cow or a perfect diamond could just
suddenly poof out of existence, Yeah, exactly, or you know,
like a banana the size of a school bus or whatever.
Could a million dollars just suddenly appear in my hands,
and instead of you know, admitting that I stole it,
I could just say that it was a quantum fluctuation.
I'm just you know, hypothetically speaking, it's called the Boltsmann heist,

(16:26):
the Boltzmann alibi. I think technically speaking, that's well beyond
reasonable doubt. But it's not impossible. Yes, absolutely you should
try that defense, and then I'll come visit you in
prison and bring you some bananas. But what if I
bring a serious physicist with me to testify. I don't
know any song, so I can't recommend one for you.

(16:47):
I only know the podcasting kind, all right, So let's
put my legal troubles aside here. So that's how it
would happen. It would happen like you know, particles would
appear out of the vacuum or get transformed from light
or something, and then they would has happened to assemble
into a brain with like thoughts and a personality in
it already, or like a blank brain with thoughts and
a personality and memories, right, because your memories are just

(17:11):
a reflection of the sort of physical state of your brain.
And so for example, somebody who thinks they are you
could assemble out there in space. Right, you could make
a whorehe brain out there which would have thought that
it lived your whole life. It is that like, maybe
I am a Boltzmann brain, maybe you are a Boltzman
brain exactly. And so we use this as a probe

(17:33):
to like think about the likelihood of various cosmological theories
of the universe. And one standard is like, does your
theory predict that there are more Boltzmann brains than actual
real people out there, you know, thinking and breathing. So
it sort of is a way for us to think
about the origins of the universe. And you know what's

(17:54):
likely and unlikely to have happened. And you know, we
can actually put a number on this probability, probability to
have a brain assemble out there in space. Really you
can quantify this crazy probability. Well, people have quantified it,
you know, they've gone through the argument and thought about
how many particles and what are the chances for this
to happen and that to happen for them to assemble,

(18:16):
And you know, the point is you get a number
which is really really small. It says that it should
happened about once every ten to the ten to the
fifty years. That means if you wait a number of years,
which is ten with ten to the fifty zeros in
front of it, you should get a Boltsman brain. That's insane.
It's like ten to the zeros to tend to be

(18:38):
ten with fifty zero's past it. Wow, that is a
really big number and much older than the age of
the universe, right, like the age of the universe, it
just tend to the eight or nine. Yeah, exactly, we're
fourteen billion years so, like you know, tend to the ten.
So basically, it's a pretty low probability for one to
have happened so far in our universe if the universe

(19:00):
is only fourteen billion years old, if you believe that,
if that's true, or if the universe is only going
to be fourteen billion years old, but I who knows,
maybe it will have a long, crazy life exactly. And
so the point is that it's very very unlikely. But
it's sort of like a standard, like your theory the
universe should not predict something like this happening because that
seems pretty absurd and unlikely, but I guess the point

(19:21):
is that the probably is not zero, Like it's possible
for a brain to appear out of the blue, even
if the probability is small, Like you can roll a
pair of snake eyes on a pair of dye. It's unlikely,
but it does. It could happen on your first roll. Yeah, exactly,
and in some way, like everything that is happening was
very unlikely, like the chances of me existing are almost zero.

(19:45):
In the same way, so many things have to happen
just right for me to exist, and yet here I am.
I do exist. So some things, even though they're vastly improbable,
do actually happen. All right, Well, let's think about why
we think about this crazy scenario and what it has
to do with the Big Bang and explaining what happened.

(20:05):
But first, let's take a quick break. All right, we're
talking about Boltman's brains and big bangs, about of bees today.

(20:27):
Boltsman sounds like an ad for I don't know, a
mattress store by your space brains. Come on down to
Boltsman's brains and you're bananas. All right, Well, this is
a crazy scenario. The idea that you know, a brain
could spontaneously form out in space out of random particles

(20:49):
popping into existence. They could assemble into something that thinks
and has the exact same memories as you, and that
could maybe, for like a second, think that it is you, right,
because this brain would be alive for you know, a
little bit of time, right, Yeah, exactly. The brain would
survive for a little bit of time long enough to think, Wow, look,
I'm a brain. I think I understand the universe, or

(21:11):
I'm gonna go get a banana or whatever. And you know,
if you're living in the moment right now, you don't
know that you're not a Boltzman brain, you know, then
and about to disintegrate, you could be right, like everything
that's happened to you before it could just be an
implanted memory. Yeah exactly, Nothing that you have fought in
the past could be real. Wow, all right, Well this

(21:31):
is super highly unlikely to the tune of one intent
to the tent to the fifty. But it's not zero
the probability, which means that if the universe is infinite,
it's happening all the time now right there are brains
popping out into existence everywhere. Yeah, exactly. If the universe
is infinite in extent, right, spatially infinite, it goes on
forever with an infinite amount of stuff and totally random

(21:56):
initial conditions, and then everything that is possible is happening,
even if it's very very unlikely. So that means that
somewhere out there right now, if the universe is infinite
and totally random and the initial conditions, there is a
Boltman brain appearing and thinking that it's me. And so
this whole wild idea has a lot to do it.
As you were saying, thinking about probability in the universe

(22:19):
and what are the chances of things happening, and specifically
kind of like how you compare that to the Big Bang,
because the Big Bang is also pretty unlikely. The Big
Bang is very unlikely exactly. And you know, the current thinking,
of course, is that the universe started about fourteen billion
years ago, and we think that because we look at
the expansion of the universe and we track it back

(22:39):
and we look at like the oldest things in the
universe and they seem to be about that age, and
so there seems to have been this special moment early
in the universe. But you know, we don't know what
comes before the Big Bang. We don't know what caused
the Big Bang. So while our universe seems to have
come from a very special state fourteen billion years ago,
we really know very very little about the origins of

(23:02):
that state, what created it, what caused it, if anything,
if it even means anything to say this something before
the Big Bang. You know, we have lots of different theories,
and some of them say that there is nothing before
the Big Bang, that's face in time, didn't even exist,
and other theories that say, you know, maybe there was
something before the Big Bang. We talked about pen roses
conformal cosmology that talked about the universe continuing to expand

(23:25):
like flower pedals upon flower pedals. So the point is
we don't know it all about what happened before the
Big Bang, which means that the universe could have existed
before it could have gone on basically infinitely into the past,
or a very long time into the past, or maybe
I guess the interesting and alternative is that maybe the
universe just popped out of existence out of the blue,

(23:45):
just like one of these Boltzmann brains. Right, that's one idea,
and this is sort of the direction that Boltzman was
going when he was thinking about entropy and probability. As
he was developing his theories in the late eighteen hundreds,
he realized that the second law of thermodynamics that tells
you that entropy is always increasing, that things basically tend
towards equilibrium, that our universe is sort of tending towards

(24:09):
a state where everything is going to be equally spread out,
and they call this the heat death of the universe.
He realized that if the universe goes on for a
very very long time, and this is sort of the
eventual end of the universe, that the universe would spend
most of its time as the heat death universe. Like,
eventually you get to the equilibrium, and then you just
stay there forever and ever and ever for the whole

(24:30):
life cycle of the universe. And so he realized that
it's kind of weird to not be at that point.
It's sort of strange and very unlikely, almost vanishingly unlikely,
that we're in a moment that's not at maximal entropy, right.
It's it's like, it's weird that there was so much
stuff kind of condensed in one place that would eventually
expand and explode into planets and people and bananas. Yeah, exactly.

(24:53):
And so his solution to this sort of paradox to
thinking like, if the universe just trends towards maximum entropy
all the time, then it should basically always be a
maxim of entropy. His solution was like, well, maybe there
are fluctuations. Maybe you can get the universe into this
like totally smooth state, but then randomly in some corner
or the universe, boom, it fluctuates to a lower entropy situation.

(25:16):
And so in his thinking, because entropy was statistical, it's
it's like property that came out of the motion of
the little particles inside it, not absolute that you could
get like little deviations, little moments when you break this
second law of Thuring dynamics, where things get a little
bit lower entropy. So, for example, he imagined, maybe the
universe is this vast pool that's in the heat death.

(25:37):
It's totally in equilibrium, but then a galaxy fluctuates out
of existence, and that's us. So he imagined that our
entire existence might be this like fluctuation out of equilibrium
of an otherwise like vast universe that's just sort of
like smooth and featureless, like you're a bubble in your
peanut butter or something. Well, that's a very humble analogy

(26:02):
for our entire galaxy. But we're not just one galaxy.
We can count trillings of galaxies out there. So it's
the idea that all of those streelings of galaxies are
just like a again, like a bubble in a in
a jar of peanut butter. Well, Boltzman was thinking about
this before we really understood the context of our universe
at all. This is the late eighteen hundreds, before people
even understood that there were other galaxies. That wasn't until

(26:24):
later when Hubbles saw those galaxies and realized while the
universe is much bigger than we ever imagined, and it's expanding.
So it makes Boltsman's strategy that's like, well we could
just fluctuate a galaxy out of equilibrium much more difficult
because now you have to fluctuate like the whole universe.
You have to take like the Big Bang and say
this entire Big bang, this like moment of crazy high density,

(26:47):
which led to, as you say, our entire universe with
galaxies and superclusters. That whole thing was a fluctuation, And
that's when the problem of Boltzmann brains arose because people realized,
you know what, that seems pretty unlikely. It's much more
likely to just fluctuate a brain. I mean, now, fluctuating
a whole universe out of equilibrium seems much much less

(27:09):
likely than just fluctuating one brain, which seems like pretty
reasonable in comparison. Is the idea that, like the universe
as we see it now suddenly appeared, or that the
Big Bang initially is one of these bubbles in the
peanut butter, you know what I mean? Like, is the
idea that we sort of like popped into existence the
way it is now with the galaxies moving at just
the right speeds and everything moving away from each other coincidentally,

(27:34):
Or is the idea that the maybe the Big Bang
was sort of the this bubble forming. The idea is
that the Big Bang was this bubble forming, right. That's
the concept of this kind of cosmology. It's not that
we're all being fooled and thinking that the universe existed
and then it just actually popped into existence right now
with this apparent history. It's that the Big Bang itself

(27:55):
was a fluctuation that the vaster universe is this ocean
of equilibrium at of which fluctuated this crazy condition, this
crazy low entropy state, which was the Big Bang, And
then physics sort of rolls forward the way we expected
and the way we've observed, and all of our experiments
are honest and actually have measured the history of the universe.
But this is an argument that's used to criticize that idea,

(28:18):
say that idea is so ridiculous and so absurd and
so unlikely, that it's more likely that you have this
other absurd scenario that we're all just Boltsman brains floating
in space. I guess you're saying that the universe is
so unlikely that it's more likely then that we are
all just all came into existence yesterday. That's the Boltsman

(28:40):
brain argument exactly. Says that if you believe that, then
you should also accept the possibility of Boltzmann brains. And
in an universe that has lived for a very very
long time, there'll be lots of Bolsman brains, and the
probability that you're not a Boltsman brain but like an
actual brain, seems very vanishing lee small, and so they're
for most likely we're all boltspan brains. Daniel, Are you

(29:02):
saying that there's a possibility that the Bible is right
and that actually it's more likely than your current theories
of physics? Is that what you're saying, Daniel? Can I
get you on the record to say that. You cannot
get me on the record to say that. You know,
this is one method that's used to sort of critique
this kind of cosmology, this particular idea that the Big

(29:26):
Bang was a low entropy fluctuation. It can be criticized
by this kind of argument. But you know, as we
can dig into in a minute, there also criticisms of
this argument, like you know, the boltspen brain argument itself,
like does it really hold up as a way to
evaluate the likelihood of the Big Bang as a fluctuation? Oh?
I see, we're still in thought experiment mode. It's not

(29:48):
that just because the Big Band is less likely that
than the idea that we're all just made yesterday. That's
not a good argument. We're still in thought mode. Yeah,
we're still in thought mode. And you know, just being
unlikely is in devastating. As we said, unlikely things do happen,
and so it certainly is possible that something unlikely happened,
and we're here anyway, that the reason, for example, that

(30:11):
we are here asking questions about why this unlikely thing
happened is because the unlikely thing happened, and otherwise they
wouldn't be anybody to ask these questions. So that's, for example,
one way out of this predicament. All right, well, let's
dig into what is wrong with this argument and why
it's maybe not possible for brains to spontaneously form out

(30:31):
of the blue, and most important, what does it all mean.
But first, let's take another quick break. All right, we're
talking about spontaneous brains, and sometimes I have spontaneous thoughts.

(30:54):
That's not the same thing, Daniel. Right now, all your
spontaneous thoughts are gold. The Boltzman brains are just brains
goles out there in space. That's right. That's what I'm
doing when I'm napping. I'm just making gold. It's called cartoons.
And you know, people out there might be thinking, hold
on a second, I'm pretty sure I'm not a Boltzman brain.
How can these folks be telling me I'm likely to

(31:16):
be a Boltzmann brain? Because like you look down and
you have arms, right, and legs and how could that
possibly be a Boltzman brain? But you only have memories
and electrical impulsis in your brain telling you that you
have arms and legs. But maybe those formed out of
the bluetooth. Yeah, maybe they did. And you know, you
can take that direction, you can say, well, you only
have memories of them. But you can also go the

(31:37):
other direction, and you could say, well, you know, let's
just not consider only Boltman brains. Let's consider Boltzmann people.
You know, like, if you're gonna fluctuate a brain out
of the vacuum, and it is basically almost impossibly unlikely,
why don't you just go whole hog and make a
whole person, you know, arms and legs and everything, Well,
the full Boltzman. Think of Boltzmann booties and it's full

(31:59):
fund a bolt and a Boltzman elbows, right, yeah, And
you know this is all in comparison to fluctuate in
entire universe out of the vacuum, and so compared to that,
like everything is basically free. Even if you add like
a Boltzman room around your Boltsman body, even a Boltzman town,
it's still much more likely than fluctuating the entire universe. Really,

(32:22):
like and you can expand that to the Earth, like
the whole Earth produced profit existence with photons coming out
of just the right way for us to think that
there's a larger universe. Yes, yes, exactly, And that's still
more likely than the Big Bang. That's more likely than
fluctuating the whole Big Bang. And this was the criticism
of Boltzman's arguments. You know, Boltzman's like, just fluctuated galaxy,

(32:43):
No big deal, folks, and people like, actually, that is
a pretty big deal. Fluctuating a brain is unlikely, and
that's much more likely. And so you know, as a
way to critique either fluctuating like a Boltzmann galaxy out
of the vacuum or fluctuating the whole universe, this is
just a way to point out that that's all seems really,
really really unlikely. But I guess the core argument, though,
is still valid. Isn't it that it is more likely

(33:06):
for us to have suddenly appeared six thousand years ago
than through a big bang fourteen billion years ago if
you think that the Big Bank comes from a low
entropy fluctuation. Yeah, and again we're not just talking about
like the creation of the universe in general. We're talking
about this one idea that the Big Bang is this fluctuation, right.
There are other ideas of how the Big Bank came

(33:26):
about or how the universe was formed that are not
this one particular cosmology, But this one is susceptible to
this criticism of Boltzmann brains. It's only if you think
that the universe itself fluctuated out of the blue. But
there's other ideas. Maybe the universe didn't fluctuate out of
the blue, maybe it came from something else. Yeah, exactly.
There are lots of other theories for where the universe

(33:48):
came from, you know, and like they're all improbable and
probably wrong. We talked about them on the podcast before.
You know, maybe there was a whole universe before and
there was a big crunch, or maybe base just started
at that moment and we don't understand how and why
and it doesn't even make any sense to ask that question.
Or maybe there's an inflating eternal universe where this sort

(34:10):
of weird infloton field then decays into the kind of
stuff which can create a big Bang. So, you know,
none of these things are like well formed theories that
anybody really believes. They're all just sort of still at
the level of intellectual playgrounds, because we're at that point
where were like throwing stuff off the wall and see
which brains stick to it. You know, which peanut butter
makes any sense at all? Maybe the universe is almond butter, right,

(34:35):
or it's got a peanut allergy. But yeah, right, and
that's been the problem the whole time. You know, I
guess what you're saying is that there might be other explanations,
but for them to be scientific, wouldn't they at the
core be sort of random events? Right? Otherwise, what what
else is there besides a random event? Sorry? Are you
saying that every idea is just a random event? I

(34:57):
mean you can't actually like think hard about things and
come up with good ideas well in terms of the
origin of the universe, right, like, maybe the universe came
from another universe, but where did that universe come from?
And then at infinitum and eventually you sort of come
to a probability argument, right, Well, maybe, I mean you
might come to a single possibility. It could be that

(35:18):
you discover that the laws of physics can only work
in one way, and the universe could have only started
in one way and be self consistent. It certainly is
possible to reveal that the universe has to be a
certain way because the laws only work. For example, if
that happens, and that that, I think is sort of
the hope and the goal that we'll get back to
the very beginning of stuff and we'll realize, oh, this

(35:40):
is the only way that makes sense, and so that
must be why it is this way. But we have
no guarantee. It could be an infinite ladder of questions
leading to questions leading to questions. We have no guarantee
we're ever going to make sense of it. That's making
my bols my brain hurt a little bit, and that's
not just because I'm in the middle of the sun
or days. So I guess. Then let's get back to

(36:02):
this question. Then are we a Boltzman brain and my
Bolthman brain? How can I be sure that I'm not?
You can't actually be sure that you're not a Boltman brain,
But you can use your brain to sort of reason
your way out of it, right. You can make arguments
that convince you that you're probably not a Boltzmann brain.
And this is you know, some good arguments out there.

(36:23):
One of my favorites comes from Sean Carrol. Right, Sean
Carroll thinks about this stuff pretty deeply, and you know,
he points out that if you're a Bolthman brain, that
means that most of the things you think are not
based in reality. They're like false memories that are implanted
in your brain when your Boltman brain assembled. Right, you
didn't actually go to that elementary school, you didn't actually

(36:47):
marry that person. That's all just fake memories. Right. Wait, wait, wait, wait,
he's saying that we are that or we're not that.
He's saying if you're a Boltzman brain, then all of
your memories and all of your thoughts are false right there,
just assembled randomly. They're not based on real experiences, real
inside into a real universe. And that includes the idea

(37:07):
of Boltzmann brains. So if you're a Bolsman brain, then
you shouldn't trust any of your ideas, including the idea
of Boldsman brains. What that's not right? Just because I'm
dreaming or because I'm an illusion doesn't mean that there
aren't real things that could exist outside of me. Right,
that's right. Yeah, but your thought about Boltzmann brains could

(37:29):
have not come from a careful analysis of the universe
and it's likelihood. It could just be like I'm made
up crazy idea and planting your brain because you know,
it just happened to come that way when the particles
assembled themselves out there near Alpha Centauri. It could have.
But it also could be the opposite, right. It could
be that it is true. It could be that it's true, right,
but you have no basis for believing that it's true

(37:50):
just because you're thinking it, right, I mean, he says,
if you reason yourself into believing that you live in
such universe with Bolsman brains, you have to conclude the
have no justification for accepting your own reasoning because the
reasoning and Boltman brains is by definition unreliable. They're not
doing any reasoning, they just like have ideas. And I
think you're saying that the argument against this crazy idea

(38:14):
is that if you are like a spontaneous brain that
formed with all these crazy thoughts in it, then you
can't really say anything about reality, Like maybe all of
what you think are the laws of physics could just
be some kind of sort of bogus random assembly of
molecules in your head. Yeah, you can't like at the
same time, conclude that you live in like a randomly

(38:34):
fluctuating universe creating brains, and believe that you have good
reason for listening to those brains. Well you could, but
you just wouldn't be a serious train. You'd be a
brain cast exactly. So he says that the whole idea
is what he calls cognitively unstable, that if you believe
in it, that gives you reason to not believe in it. Right,
And so it says the whole thing sort of falls apart. Well,

(38:55):
it doesn't fall apart, it just makes it questionable, right,
but it's good still be true, right, you have anything
could still be true. That's a low standard. Remember we're
using this idea is a way like probe the likelihood
of a cosmological theory, of saying could the universe be
this way? And the argument is if your theory the
universe suggests there are more Boltman brains than not, then
you're not really going to believe in it. And this

(39:17):
is just a way of saying, you know, okay, Bollsman
brains are bad, but you know, you can be pretty
confident that you're not a Boltswin brain. If you're forming
like well thought out, coherent ideas. What if Einstein was
a Baltzmann brain and he happened to be right? Yeah? Maybe?
And you know you have to also wonder, like, should
you listen to your own ideas? Right? If the universe

(39:37):
is filled with bullspin brains, probably more of those Bollsman
brains are not very clever. Then there are Bollsman brains
that are like Einstein, right, Which means that you're probably
not Einstein, which makes you wonder, life, should you be
listening to your own thoughts about the universe. I don't know.
It's the most insulting thing I've heard from me, Daniel.
You still, I'm probably not Einstein. I mean, Einstein was

(40:00):
and smart enough to come up with your peanut butter analogy.
I got that on him. Yet, maybe I'm smarter than Einstein.
Maybe you're right, Maybe I'm not Einstein. Maybe I'm better
at cartooning than eight Stein. Yeah, I'm sure that's true.
This is part of that counterpoint that you were talking
about that you mentioned, is this idea that there could
be Boltman brain, but there may not necessarily be smart

(40:22):
Boltzmann brains. Yeah, exactly, So we could be a bunch
of Bolsman brains, so to fool on ourselves into believing
some silly argument about the origin the universe because we're
not a wave, so we could be Boltman brains foolishly
thinking that bolts when brains are possible. Yes, but then
we would be right if that's true. You might have

(40:43):
to be a dumb Boltmann brain to believe the dumb
Boltman brain idea doesn't make any sense. You just proved yourself.
Oh man, it's confusing, all right, Well, then what's the
other alternative? I guess if the universe is not a
random fluctuation, you know, there are sort of two other alternatives.
One is to accept that maybe the universe was a

(41:05):
really unusual, unlikely fluctuation, and then just to say that's okay, Like,
sometimes really rare things do happen, even like unfathomably rare,
like an entire big bang coming into existence out of
thermal equilibrium. Sometimes they do happen. And this is what
we were talking about before. It's the anthropic principle. It
says that it's okay for unlikely things to happen if

(41:28):
they're necessary for you to be here to ask questions
about how unlikely they are. Maybe the universe is infinite
and this kind of stuff almost never happens. But in
the places where it's not happening, there's nobody noticing. There's
nobody asking like, hey, how come we didn't get a
big bang over here. It's only in the places where
you do have a big bang and then people to

(41:49):
ask these questions that you ask these questions. So it's
like me saying, what's the probability of me existing? I
can't rule out my own existence by arguing that I'm
unlikely because I did happen. Right. It's like you're a
pair of snake eyes and a pair of die right,
Like you're two ones, and you're thinking, like, oh my god,
what that's crazy that I exist? But you don't know

(42:10):
if the universe, you know, through the paradise bazillion times
before you existed. Yeah, exactly. And I don't really like
that argument that much. It feels to me like sort
of a cop out. It says, there's no answer. Stop
asking questions. You know, there's no reason for this very
unlikely thing. And in science it might be true. But
in science we've made a lot of good progress by

(42:32):
looking at weird stuff and going hmm, that's weird. I
wonder if there's more to the story, And that's usually
the way we pull on threads and unravel something deep
and true and interesting about the universe. So can't disprove
the anthropic argument. But it's sort of like it doesn't
give you anywhere else to go. There's nothing deeper you
can do after you answer a question that way, So
it's not really very satisfying. I'd like to keep digging. Well,

(42:54):
you could keep asking like who through the die right,
or like how does the die throwing work? That would
explain and and it'd be interesting to look into. Yeah, absolutely,
but it doesn't answer the question of like, why is
our seemingly impossibly unlikely universe exists? He says, well, it
just kind of does. Well, I think that's a perfectly
good reason. I mean, I tell it to my kids
all the time, just because why can't you watch more TV?

(43:18):
Just because because Daddy needs you to go to bed?
Because my Baltzman brain says so, because my baltmonan gratest tired.
I guess the idea is that maybe our universe did
come out of this super crazy, unlikely event, But that
doesn't mean that within it you can have these crazy
Balthman brains floating in it. Yeah, And I think the
other sort of category of answers is to say, all right,

(43:40):
you're right Boltzmann brains suggest that the universe as a
low entropy fluctuation is super unlikely. So let's focus on
other cosmologies, other ideas for how the universe started that
don't require it to have existed forever and then fluctuate
into a big bang. Things that where the universe actually
did start for billion years ago, or there's some other

(44:02):
mechanism for creating the Big Bang other than it's just
like weird random, super low entropy fluctuation. All right, I
guess maybe we just have to keep our fingers crossed.
Then it's that kind of the general approach here that
there's a lot we don't know, and we don't know
what these actual probabilities are. Yeah, and this is just
a fun way to sort of like explore these ideas

(44:23):
and to think about the consequences. You know, we have
such an incredible lack of knowledge about the early universe
and such an incredible variety of kind of bonkers ideas
for how it could have come about that it's useful
to like come up with these arguments to evaluate them,
because we can't like go back in time and see
what actually happened, or journey around the whole universe and

(44:43):
gather the data we need. So until then we just
are stuck here on Earth in our brains, whites and
brains or cham brains or Boltsman brains, thinking about the
origin of the universe and convincing ourselves that maybe we're
making progress. Yeah, that's a good point, David, you just
woke me up from my nap. I was doing some
thought experiments. David and Klan nap their way through the universe.

(45:06):
We could replace ourselves and none of the other Bolsman
brains would notice the difference. Maybe our Bolzman listeners would notice.
All right, Well, we hope that gave you as much
of a Boltzmann headache and it did for me, and
that it maybe helped you think about what's like the
out there in the universe and whether or not it's
all even real. Thanks for joining us, See you next time.

(45:35):
Thanks for listening, and remember that Daniel and Jorge explained.
The Universe is a production of I Heart Radio or
more podcast for my Heart Radio, visit the I heart
Radio app, Apple podcasts, or wherever you listen to your
favorite shows.