From the Vault: Thought Experiments

Stuff to Blow Your Mind frequently discusses thought experiments on the show, from Schrödinger's Cat to the Infinity Hotel. But what constitutes a thought experiments? How long have they been around and what are the seven categories? Robert and Joe explore… (Originally published Jan 3, 2019)

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

See omnystudio.com/listener for privacy information.

Episode Transcript

Speaker 1 (00:05):
Hey, you welcome to Stuff to Blow Your Mind. My
name is Robert Lamb and I'm Joe McCormick. And it
is time to go into the vault because it is Saturday,
of course, and we're bringing you an episode that originally
air January third, twenty nineteen. That's right, what's inside the vault?
I don't know what's not inside the vault. The thing
inside the vault could be alive, it could be dead.
It's kind of in a quantum position until we open it. Right, Okay,

(00:29):
this is our episode about thought experiments. Yeah, I remember
we were asking the question, what can you really prove
anything with the thought experiment? Yeah? I think you can. Yeah,
I think we You know, obviously we're we're pro thought
experiment on this show. We devote whole episodes to particular
thought experiments. But I remember this was when we were like, hey,
let's stop and just actually discuss thought experiments, especially if

(00:49):
we're going to keep uh invoking them on the show. Uh. Well,
I say, let's get right into it. Welcome to Stuff
to Blow your Mind from how Stuffworks dot Com. Hey,
welcome to Stuff to Blow your Mind. My name is

(01:10):
Robert Lamb and I'm Joe McCormick, Hey, Robert, what are
we talking about today? Oh, well, we're talking about thought experiments,
the things that make some people really mad and make
other people talk for way too long into time. Well,
the thought experiments can have both effects on an individual
at the same time. That's the beauty of a thought experiment.
I think. So now, we've discussed individual thought experiments on
the show many times before, but I think today we're

(01:32):
going to try to look at the idea of a
thought experiment on the show. In the past, we've talked
about specific thought experiments. We've talked about Stranger's Cat, We've
talked about the Infinity Hotel, the ship of Theseus. Other
times it comes up kind of informally. We might say
that a particular paper we're talking about is more kin
to a thought experiment. And I know that I've I've

(01:53):
talked before about how I think of certain short stories
as being more thought experiments than you know, true narrative.
I think of Library of Babbel, Library of Babble, other
works of a lot of the short stories of jor
Haluis Borges, as well as a number of the short
stories of Philip K. Dick they're a number of those
where you know it's not really important who's doing what exactly.

(02:13):
You know you're not you're not really invested in a
story per se, but the story is there to make
you think, to turn some sort of weird idea on
its head, the concept driven more than character driven exactly. Now,
I have to say that one of my favorite comical
treatments of thought experiments is the humorous essay Shreddnger's Cat
by Steve Martin, collected in his book Pure Drivel. And

(02:34):
there's a wonderful audio book of this as well, because
Steve Martin himself is reading it. Always great when you
can get one read by the author. Yeah. Now, Martin
begins this particularly essay by presenting the Streusenger's Cat thought
experiment just pretty much as it is, and from there
he proceeds through an increasingly ridiculous mix of thought experiments
that he's made up himself, such as uh vitkin Stein's banana,

(02:59):
Elvis's chart ol briquette, chef boy r ds, bungee cord,
sakagaway is rain, bonnet, apollos, non apple, non strutal, Jim
Dandy's Bucket of Goo, and the thinman dilemma. Since it's
one of the shorter ones, I'd like to read Steve
Martin's description of the thought experiment Elvis's charcoal briquette. A

(03:22):
barbecue is cooking wieners in an air tight space. As
the charcoal consumes the oxygen, the integrity of the briquette
is weakened. An observer riding a roller coaster will become
hungry for wieners, but will be thrown from the car
when he stands up and cries, Elvis, get me a
hot dog. Yeah, that's got the right mouth field. I mean,

(03:43):
it's it's absurd, it's ridiculous and uh, but it's effective
as comedy because it does have that feel of a
thought of experiment, and and many of them are exactly
this sort of absurd little logic problem or physical scenario,
but it's utilized not for laughs, but to explore some
sort of generally a complex topic. I thought this was
going to be the seventh thought experiments. You can't say

(04:04):
on TV. It does make me wonder what the most
risk a thought experiments are. Oh, there are actually quite
a few. Yeah, all right, well, let's we'll save that
for the midnight Show. So let's let's talk about thought
experiments just definition wise, like, what is a thought experiment? Well, yes, first,
you could consult the idea of an experiment. An experiment

(04:25):
is basically a test, like you have a condition and
you you instantiate the condition and you see what happens. Yeah.
But on the other hand, it's worth pointing out that
to merely think about an experiment is not a thought experiment.
So if you if you say, for instance, think about
the social psychology Stanford prison experiment, that's not a thought experiment.

(04:48):
Um why not? Well, because you are you were thinking
about an actual experiment that has been carried out. I
mean this is kind of obvious, right, but but still
it it it's worth going through. Now, if you if
you think about an experiment you might conduct, say to
see if movie goers who eat twizzlers are more likely
to joy to enjoy sci fi films and those who
eat red vines. Well, that's not a thought experiment either.

(05:10):
That's something you could conceivably do. That's like imagining an
experiment you could carry out. But thinking about the experiment
doesn't really reveal anything right now, Very often the experiment
in a thought experiment is exactly not the sort of
thing that could be carried out in real life for
a number of reasons. Maybe it's catastrophically dangerous or or involves,

(05:33):
you know, in encountering some feature of the universe that
is not readily accessible. That sort of thing. Very often
thought experiments, as they apply to science, involved the the
removal of things that you couldn't actually remove as variables,
so like imagine a frictionless plane, or involve something that
just simply does not exist, like a train going near

(05:55):
the speed of light. We do do not have such
a thing. We're probably not going to have such a
thing anytime soon, but it's useful in the thought experiment.
And then on top of that, they frequently are narrative
in nature. There's a sequence to things in a way,
they're they're almost like a joke in many senses. You know,
it feels like the set up for a joke. It
feels like there's going to be a punch line. Um.

(06:17):
And I also I wondered to what extent like really
successful and quote unquote successful thought experiments, like ones that
really resonate culturally, if if there is a sense of
counterintuitive elements to the narrative. I wonder if there's something
about that as well. Well. Yeah, thought experiments are an
interesting thing. So like a good thought experiment, what it

(06:37):
should do is reveal something that is true simply by
making up a story in your mind and working through
the conclusions that would result from it. Now, often there
are a lot of coincidental details of this story that
do not matter. Uh, they don't have any effect on
what this thought experiment reveals, if it reveals anything, and

(07:00):
yet they can be enormously predictive of whether or not
this is like a popular meme or not how well
it spreads. Like cat as an example, Like if it
were a dog, it would probably still resonate, but in
a slightly different way. But if it were just a
lizard or a slug, yes, people would be far less
compelled by the idea of Shreddinger's bug, but they would

(07:21):
be far more upset by the idea of Shreddinger's child
or something. So like, if it's a cat, that's the
bull's eye, that's right in the red zone. It's like
interesting enough to be killing a cat that people are
on board to to remember to pay attention, but it's
not so troubling that you're turned off and you don't
want to listen, right, And and then also the cat
kind of makes it more palpable. Like if it was

(07:43):
Shreddinger's um, let's say, basilisk, that would it would instantly
sound a little more threatening somehow. How about Shreddinger's apparently
conscious AI Yes, or that's the that's next level. Yeah,
that's that's pretty good. Now. Another or an aspect of
thought experiments is that it's something that should generally be

(08:04):
visualized in the mind as this, as the thought experiment
has rolled out, you you're picturing it. Uh. It's in
doing this it makes a concept more digestible, or it
explains a you know, fundamental paradox, etcetera. And uh, and
and and this again. It has a lot in common
with jokes, It has a lot in common with riddles,
and they just sort of the basic structure. But it's

(08:25):
not necessarily bringing you to uh. It's not bringing you
a punch line. It's not necessarily a correct answer at
the end. But there is hopefully a deeper understanding of
a concept via the thought experiment. Now that being said,
a thought experiment is also not a pristine, blameless thing
or something set in stone. So others may take issue
with the thought experiment or just completely knock it down.

(08:45):
They may roll out their own thought experiment that attempts
to put your thought experiment to shame. And uh, and
there may be you know, additional interations off and we've
certainly explored that on the show before with things such
as the ship of Theseus. And then finally, one of
the really cool things about thought experiments is that it's

(09:06):
ideally this this chance to learn about reality, learn more
about reality by simply thinking about it. And that would,
on the surface of things, seem rather odd, right, because
it would be an exception to the empirical nature of
how we learn about the world by seeing it, by
touching it, by feeling it, by poking it, by dissecting
it and running, um, you know, more or less physical

(09:27):
experiments upon it. But to simply think about something and
the idea that that will reveal something that we had
not seen before it was not clear to us beforehand. Uh.
That that's rather curious, isn't it. Well, yeah, I mean,
a thought experiment is a type of logic, which means
it it lacks the empirical data gathering part of learning

(09:48):
about the world, so all it can do is draw
conclusions from what is already known or assumed, though there
have been plenty of cases where in fact, in the
history of science interest stuff has come to be known
without anybody going out and measuring anything new, but just
by applying what was already known in a logical way

(10:09):
to arrive at a new conclusion. We'll talk about examples
of that in a minute, all right, So I want
to mention one quick example. Uh, it's not so quick
in the original text, but Lucretius, who lived nine b
C b C. Wrote on the Nature of Things Sura, yeah,
and uh, and he has a fun little thought experiment

(10:30):
he rolls out. So um, Lucretious argues that space is
is infinite and what you say it isn't? Well, fine,
then let's march a soldier to the edge of the
finite universe and have him throw a spear at the edge. Wait,
what is the soldier's name? This is crucial. Oh I
see I skipped that part. What is the soldier's name? No,
I don't know. It's that we don't need to know

(10:51):
his name. It's just a soldier. We could we could
call him cat. I guess, but um, his original write
up of it is a bit longer. This boiled out. So, yeah,
march the soldier up to the edge of the universe.
Haven't throw a spear at the edge. Well, one of
two things is going to happen, he says, Well, if
it flies through, then there is something beyond and your
barrier is nonsense. Right, So the universe is not actually

(11:14):
bounded there, right, because you just threw a spear beyond
the edge. Now if the spear bounces off the barrier, well,
then the wall itself is proof of something beyond your
your your spear just bounced off of something. What is
that something? The wall is a thing? Yeah, so it
In looking at this, you can see that it illustrates
a conceived version of reality and lays out an experiment,

(11:38):
And of course it also illustrates one of the other
features of thought experiments you can pick at them. So
Lucretius may have presented this, as you know, as a
real sentence stopping comment on the nature of the universe
at the time, but certainly, if you if you think
back of even discussions that we've had on the show
about infinities and different types of infinities, and and some
of the arguments for you know, for exactly how I

(11:59):
find ie universe would work. Then you can see that
his argument doesn't quite hold up to modern cosmology well
as you've presented it here. This is actually a great
example of how thought experiments can seem brilliant but actually
produce flawed conclusions because they contain drum roll hidden assumptions. Here,

(12:19):
I would say one fatal hidden assumption is that Lucretius
takes on board without considering the geometry of a finite universe.
Now again, I'm certainly not going to go and argue
that space is finite. That's not my goal here. But
my I would say there are ways in which space
could be finite that Lucretius is overlooking with this example,

(12:43):
because there are different ways you could imagine a finite universe.
One is a sort of closed three D space with
exterior walls like the inside of a box. And this
is sort of what Lucretius seems to have in mind here,
And of course it does seem somewhat absurd. How could
the universe be like that? It seems like it probably
couldn't be. But what if the universe is simultaneously finite

(13:04):
and without boundaries, like the length dimension of a mobius strip. Robert,
have you ever made a mobius strip, like in geometry
and school. Yeah. So you just take like one length
of a piece of paper and then give it a
half turn and then tape its ends together, and what
you have created is a piece of paper that has

(13:24):
one continuous side. You can start drawing a line and
it goes on the entire thing. So for instance, and
this this version, the soldier throws the spear and impales
himself in the back exactly as long as the spear
goes long enough. Yeah. So the idea, or it could
be another analogy here, could be that the geometry of
the three D universe is sort of like the two

(13:46):
D geometry of the surface of a sphere. It's not infinite.
The surface area of a sphere is finite. There is
a limit to it, but it has no boundaries. You
never reached the edge. So yeah, that soldier, let's let's
call him Tim. Tim throws the spear and it hits
him in the butt. Yeah. Yeah. This also reminds, you
know the idea of saying, well, hey, my soldier throws

(14:07):
a spear at the edge of the universe and it
keeps going, then your your argument is nonsense. It also
kind of sounds like, oh, we had a really cold
weather today, I guess there's no global warming. I guess
there's no climate change. Using a far simpler model than
the than the complexities of reality, try and make your argument. Well, yeah,
but it does also. I mean, I would say that
this is a good argument against a certain type of

(14:28):
idea of the bounded universe, because if if the universe
were actually finite in that it had walls on the
outside of it, at any place you approached the wall,
you could test that condition, right. So I would say
that highlighting absurdities in a single test case of the
idea of a universe with walls on the outside of it,

(14:48):
that I think that's a valid way to criticize the concept. Now,
I do have to say at the same time, Lucretius
is a little thought experiment here, even to modern readers
it it still does something when you think about it,
like it does force you to think about uh these
ideas of the finite and the infinite. Uh So, just
as like a simple thought experiment is kind of a

(15:09):
logic puzzle, it still carries its own weight. Now, they're
absolutely have been thought experiments that have been extremely useful
and powerful in the history of the advancement of science,
that have not just like made a clever seeming point,
but have actually pushed science forward. And these happen a

(15:29):
lot of time in the history of physics because physics
experiments work best when you can tightly limit the variables.
But in reality, it is very hard to tightly limit
the variables on pure physics experiments. Uh there there's often
just a lot of like more more friction and more resistance,
more whatever than you actually want. But here's an example.

(15:50):
Let's say you go up on top of the Washington
Monument and you drop two objects side by side. They're
the same shape, but one is heavier than the other.
Let's say one, say, plastic DVD of Flubber and the
other is the new Criterion edition of RoboCop two, which
has a jewel case made out of lead. So which
one hits the ground first, Well, ideally they're both going

(16:10):
to hit the ground at the same time, right, And
you know that because we live in a post Galileo age,
the post Copernican post Galileo age. But this might have
been kind of a shock to you if you lived
in say, ancient Rome or in medieval Europe, where it
might well have been assumed that the heavier object would
hit the ground first because heavier objects fall faster. For

(16:33):
hundreds of years, the conventional wisdom was along these lines.
It followed our intuitions, like, it makes intuitive sense that
a heavier object falls faster because let's say it's harder
to push a heavier object up a hill, right, so
it would seem that a heavier object should fall to
the ground through the air faster than a lighter object.

(16:55):
This was the dominant strain of thinking also in in
the sphere of scholars who revered the physics of Aristotle.
Aristotle wrote in in his work on Physics that objects
have a natural motion, They have a nature, and they
have motions specific to their nature, and that part of
that nature is mass, and so heavier objects fall to
the ground faster than lighter objects. Now, Galileo Galilei was

(17:18):
reported by some biographers to have actually performed an experiment
of this kind by like dropping cannonballs of different weights
from a tower. But whether or not this story is
true about the physical experiment, Galileo definitely showed that you
don't even need an experiment to prove that there is
something wrong with the Aristotelian view of falling bodies. He

(17:39):
could show it was wrong just by dreaming up a
scenario in his head. As and as with many of
the great intellectual smackdowns in history, Galileo didn't just explain
his position. He wrote a fictional Socratic style dialogue, complete
with a slack jawed fool to represent the opinion he
was attacking. And that fool is named Simplicio. That's pretty good.

(18:03):
Then he's also he's got a smart guy named Salviati
to represent his own point of view. And this was
in Dialogues concerning two New Sciences. In so, first Salviati
and Simplicio argue about experiments concerning cannonballs and bird shot
and stuff, and Simplicio is not moved from the Aristotelian

(18:23):
position that objects fall through a medium with a speed
proportional to their mass. And so I've tried to reconstruct
the next moment in the dialogue, but sort of rewritten
in more modern English and simplified to the main points. Robert,
would you like to do a reading with me? Sure?
What kind of accents are we going for here, Robert,
you're gonna be the smart guy. How about you give
me a combination of like Gandalf wizard Saruman pronouncing from

(18:49):
from the top of the Tower of Knowledge, combined with
like Sam Elliott wise old cowboy. All right, I'll give
that a goiin. Now, look here, we don't even need
to do any experiments to prove that Aristotle is wrong
and a heavier body does not fall faster than a
lighter one. Let's take Aristotle's principles as granted for a minute.

(19:11):
What are those principles. Well, body falling in a fixed
medium like air has a fixed velocity, and that's determined
by its nature. And you can increase this speed unless
you add momentum, and you can't decrease this speed unless
you offer some resistance to slow it down. It's all there,
and its nature. It's a fixed velocity. Great, So imagine

(19:32):
two objects with different natural speeds, maybe a pebble which
falls very slowly and a great millstone which falls very fast.
Now time together. The fallen millstone will be slowed down
by being tied to the pebble, which is forced by
its nature to fall slower right right. You are, according
to Aristotle, that pebble is going to slow down the
bigger rock because it falls slower. Okay, okay, So by

(19:55):
by tying the two stones together, the slower falling pebble
should reduce the speed at which the millstone falls, making
its speed less than it would have been alone. But
at the same time, when you tie them together, their
combined masses greater than the millstone alone. So shouldn't they
together fall even faster than either one individually? From your

(20:17):
principles of motion, we are forced to conclude that by
tying the two stones together, the fallen speed of the
millstone is both increased and decreased. Well, dang it, I
am stumped, all right, So that that's this pretty fun
because it basically illustrates how he's created kind of like
a little political cartoon right here, right right. And I

(20:37):
also absolutely love that he makes the representative of Aristotle,
who was during the seventeenth century widely considered like the
smartest guy of all time. He names him simplicito, which
is like if somebody today wrote a dialogue trying to
refute Einstein's relativity and had the character representing Einstein's point

(20:58):
of view named like clet Us T. Dip Wad. But anyway,
Carl Popper apparently wrote of this thought experiment quote one
of the most important imaginary experiments in the history of
natural philosophy, and one of the simplest and most ingenious
arguments in the history of rational thought about our universe.
And as far as like imagining physical scenarios goes, I

(21:22):
think this is the equivalent of a reductio ad absurd
um argument. So reductio ad absurd um is one of
the most powerful logical tools we have. It's when you
combine premises that somebody holds to be true and you
demonstrate that when they're taken together, they force you to
conclude something absurd that cannot possibly be true, which means

(21:43):
at least one of the premises, even though you believe them,
actually cannot be right. And so here Galileo is basically
using two premises. One is that the the idea that
objects of different mass have different natural speeds at which
they fall, and the other is that you can add
the mass of two objects together to create a greater
combined mass. And so he constructs a scenario when it's

(22:05):
actually not implausible at all. To show that, when taken together,
these two premises implied something absurd and self contradictory. So
one of the premises has got to be wrong. And
since we accept the basic arithmetic of mass that you
can add the mass of two objects together to create
a greater combined mass, it showed that the idea of
a fixed falling speed determined by an objects mass had

(22:28):
to be wrong. So I would say this is absolutely
a case where a thought experiment actually did reveal something
useful about reality. Though of course it's it's helpful as
well that you could go out and test this with
physical objects later. You you know you do, so, even
if there's some hidden assumption that's guming up the conclusions
you're drawing from this thought experiment, you could do physical

(22:51):
experiments that would sort you out later. All right, Well,
on that note, let's take a break, and when we
come back we'll explore some more examples of thought experiments
before we just us a little bit a bit more
about what exactly that they are and how we might
categorize them than alright, we're back. So Joe is a
time for Jim Dandy's bucket of goose. No, let's do

(23:11):
Newton's bag of cheese sounds good okay, So Galileo's rocks, obviously,
are not the only famous imaginary falling objects to provoke
advances in physics. Uh The seventeenth and eighteenth century English
poly math Isaac Newton was also responsible for many famous
thought experiments that illustrated his revolutionary ideas. Probably the most

(23:33):
famous and enduring is what I'm gonna call ballistic Mountain.
So back in Newton's day and there was a lot
of confusion about different types of motion and what explained
the motion of objects in the heavens. A good example
would be let's say you drop a wool sack full
of goat cheese from a tower. Which direction does it travel?

(23:54):
Goes straight down right? You wouldn't want to be standing
under that goat cheese. And at the same time, skull
Is recognized that the Earth was spherical or roughly spherical,
as had been proved for many hundreds of years, and
it almost seemed as if objects were being pulled straight
down towards the center of the Earth, and the Earth
seemed to pull all objects toward it at a constant rate,

(24:16):
as Galileo had showed, regardless of the mass of that object.
And you see this all the time, even if you
throw an object horizontally. Let's say you are hurling a
wool sack full of goat cheese at your enemy, the
Royal astronomer John Flamsteed. A Flamsteed is too far away
when you throw the sack. Obviously the gravity is going
to pull the sack down to the Earth before it

(24:37):
hits him. Gravity always pulls down. But then contrast that
with if you look up at the heavens at night,
you will observe that the motion of the planet seems
to be governed by another force entirely. Instead of falling
straight into the Sun or into the Earth, the planet
seemed to travel through the heavens and smooth, roughly circular

(24:57):
elliptical orbits, just as the wound seems to travel in
a smooth elliptical track around the Earth. So how could
the motion seen in the heavens be so different from
the motion scene on Earth? Like was there a divine
hand guiding how the planets traveled through the void. So
Newton proposed a thought experiment in his Principia, and it

(25:18):
went roughly like this, Robert, imagine we're gonna get up
on top of the tallest mountain on Earth, the Gigantic
Monster Mountain. Maybe it's on the North Pole, all right.
I guess it wouldn't because there's no land there. But
maybe it could be the Mountain of Purgatory from from
Dante's Divine Comedy for all of Isaac Newton's sins, of
which there were many, because he was a jerk, So

(25:39):
that work off those piece. So he climbs up to
the top of the Mountain of Purgatory, Oh, which I
guess is earthly paradise, right, But but he gets up
there and he brings a cannon with him. Oh that's
that's that's already. I'm feeling it's probably breaking some rules,
but okay, yes, and it's an assault on the heavens already.
But it's an assault on the heavens in more ways
than one, more way than one, more ways than one.

(26:01):
I never know how to pluralize that correctly anyway. So
let's say you got the cannon up at the top
of the mountain. You shoot a cannon ball out parallel
to the ground at a hundred kilometers per hour. What happens, Well,
it travels in the familiar arc that any anybody who
has used a firearm like that will recognize. So it
goes horizontally at a hundred kilometers per hour while simultaneously

(26:23):
falling towards the ground at the normal acceleration, and eventually
it hits the ground with a thud. But let's say
you pack more gunpowder into the cannon and shoot the
ball out of the barrel faster, say two hundred kilometers
per hour. What happens, Well, it makes an arc again,
but the arc is a slightly different shape. It falls
to the ground at the same rate as before, but

(26:45):
this time it travels a lot farther horizontally before it
hits the ground. Now, imagine you just keep packing more
and more power into the cannon so that the ball
goes farther every time before it hits the ground. The
rate at which the cannonball falls is going to always
stay the same, but the horizontal speed and the horizontal
distance covered keeps increasing. And then combine this with the

(27:08):
idea that the earth is a sphere, which they knew
at the time of of Newton. This means that eventually
you will shoot the cannonball at a speed where it
travels so fast that it's falling arc is greater than
the curve of the Earth. So it flies and it falls,
but it never hits the ground. It travels around the

(27:28):
Earth in a continuous circle. So the cannonball is still
governed by the same two forces, gravity which wants to
pull the cannonball towards the center of the Earth, in inertia,
which wants to keep the cannonball traveling in a straight line.
But they these forces combine to cause the ball to
just keep flying around the Earth in a circle in space.
And Newton had a very famous illustration of this that

(27:51):
that sort of helped to make his point, where he
showed arcs of of cannonballs falling off and becoming longer
and longer until they just became a circle. And now
the crucial extrapolation is this is what planets due to
the Sun and what the Moon does to the Earth.
So Newton had used nothing more than an imaginary scenario
to demonstrate good reason for believing something shocking that the

(28:15):
forces that govern the heavens and the forces that govern
the movement of objects on the Earth like cannonballs or
wool sacks full of cheese are exactly the same this
is the unification of terrestrial and celestial forces. And this
this is a key principle in establishing the modern age
of physics. And it's rather brilliant to and then he

(28:35):
took something that was there was so so so much
more relatable in order to explain you know, the movement
of the spheres. Yeah, exactly. And of course this is
a case where a thought experiment, while revolutionary, was not
enough to prove the case. Fortunately Newton had conducted ingenious
real world experiments also, so in this case it was

(28:55):
the use of a pendulum combined with astronomical observations to
show that the Moon falls towards the Earth at about
the same speed as objects dropped on Earth fall toward
the ground, which is a funny thing to consider whether
you're dropping a bag of cheese out of an airplane
or watching the Moon fall towards the Earth. They followed
about the same rate, but the Moon's competing inertia and

(29:16):
position of course keep it in orbit. And there are
of course powerful implications that followed from Newton. These could
be put to use in rocketry, like ultimately we had
to figure out the delta V required to achieve lower
thorbit and to escape Earth's orbit entirely if we wanted
to say, send probes to other planets. Uh And and
by the way, I didn't make up the part about
the sack of cheese. But Newton did actually have enemies.

(29:39):
And just to tell one quick story, there was this
astronomer named John Flamsteed. I mentioned him earlier, and Newton
was pretty much a total jerk. Flamesteed was this English astronomer.
He was the English Astronomer Royal during Newton's time, and
he was working on a catalog of objects in the heavens,
and Newton wanted access to Flamesteed's catalog. Basically, he wanted

(30:01):
data so he could use it to prove his theories.
But Flamesteed wasn't done putting it together yet, believing it
wasn't ready for publication, so Newton constantly harassed and bullied
him to get this information. Eventually threw his weight around
with the English Royalty to get Flamsteed's catalog published early
before it was ready, which Flamsteed did not like at all.

(30:22):
There's also a story that Newton, as the president of
the Royal Society, went to the Royal observatory to inspect
Flamsteed's equipment, and they got into a fight, and Flamsteed
wrote that quote. Newton ran himself into a great heat
and very indecent passion, and he used Knavish talk and
called me all the ill names puppy, etcetera that he

(30:43):
could think of. So like Newton's out there like screaming
at other scientists calling them puppies, just thinking a real
real ass of himself. Yeah, anyway, shows that even some
of the smartest people ever can are not above, you know,
puppy calling. Well, it makes sense. Wasn't new In a
a more of a cat person, didn't he? Uh? Oh,
that might be for cats to move in and out

(31:06):
of the chambers of his house. I didn't look up
the usage history of that word, so I don't know
exactly what it meant to call somebody a puppy and
whatever year this was, but profanity scholars right in and
let us know, Yeah what does that mean? Did he
just literally mean like a young dog? I hope? So
that's the that's that's a funny interpretation. Well it sounds

(31:27):
like Navish talk either way, totally. So what are the examples?
Do you have for us, well, just a few quicker
ones in in physics, and of course one of my
favorites is that people dreamed up the concept of a
black hole as a mathematical thought experiment, long before any
evidence of such a thing had ever been detected. Like
we talked about this in our black Holes episode. But

(31:47):
around seventeen eighty three and seventeen eighty four, the English
natural philosophers John Michelle and Henry Cavendish dared to ask
a bizarre question. So they knew that light itself had
a speed, and they were armed with Newton's insights about gravity, inertia,
orbits and escape velocity, so they asked, what if there
were a star so massive with with such a great

(32:09):
gravitational attraction that escape velocity for this star was greater
than the speed of light. In other words, a star
so massive that even light could not escape it. And
this was perhaps the earliest formulation of the concept of
a black hole, which would later be developed by so
many other important astrophysicists Karl Schwartz, Shield Gander, Shaker, Oppenheimer

(32:31):
and others. And if you want more on that, we
have a whole episode about it from earlier. This year.
Oh yeah, we did a three parter on black holes. Uh. Then,
of course the thought experiments are huge in illustrating the
concepts of relativity in the speed of light. Like Einstein
is famous for influential thought experiments, But we shouldn't just
focus on the ones that have been very influential in physics, because,

(32:53):
of course, thought experiments are probably even more common in
philosophy than they are in physics, even more common. And
I don't want to be insulting to philosophy because I
value philosophy, but I would say even more common and
less often useful. Uh. They can still be illuminating, but
I think we need to realize that, especially in scenarios

(33:14):
where we can't actually test the conclusions of a thought
experiment in any kind of way, we should be careful
that thought experiments don't cloud are thinking more than they reveal. Well,
we don't encounter thought experiments to deal with things like morality, right, Uh,
and ultimately how do you measure those things? Yes? And
the I feel like those kinds of thought experiments are

(33:35):
especially prone to be confusing because they deal with the
lucretious problem we talked about bringing in unexamined assumptions that
are influencing our thinking without us realizing it. So I
think we should mention just one example of a prominent,
extremely controversial thought experiment in philosophy. There's been a mountain

(33:55):
of debate on this one, so I know we're not
going to be able to do it justice in the
time we have, we'll try to give it the best
quickest version we can. So this is John Searle's Chinese
Room thought experiment. Robert, I know you must have encountered
this one before. Yeah, So the question is, we know
we can program computers to mimic the intelligent behavior of humans,

(34:18):
but would it ever be possible for a computer to
truly understand something? Or can it only simulate understanding? And
this has often taken a sort of an analog of
the question of can machines be conscious? Right? And no,
we've we've discussed this quite a bit on the show before.
Maybe not specifically this thought experiment I don't recall off hand,

(34:38):
but just the idea that, yeah, if a robot may
know what it is to stub one's toe, but does
a robot really know what it's like to stub your toe? Like?
Does it? It doesn't doesn't. Does it have that experience,
does it have that knowledge? Can it? Can it sort
of hold the information in its hands and squish it around.

(34:58):
We know it can act like it understands what it
means to to feel pain, But does it really understand
what it means to feel pain? Uh so? The American
philosopher John Searle proposed a thought experiment to answer this
question in the early nineteen eighties. I think it was
first in the year nineteen eighty, and his work asked
us to imagine the following scenario. You already to go
there with me, okay, So imagine you are an English

(35:21):
speaker that does not understand a single word of written Chinese,
absolutely nothing. Then you are locked in a room with
a slot in the wall, a pencil and paper, and
a giant book of instructions written in English. Every now
and then someone from the outside slips a piece of
paper through the slot in the wall, and it has

(35:42):
a string of Chinese characters written on it. And then
you look at this piece of paper and you consult
your giant instruction manual, and the manual tells you given
certain Chinese character inputs coming through the wall, which Chinese
characters to write on a piece of paper and put
back out through the slot in the wall. So you
write down what the instructions tell you to write based

(36:04):
on what has come in, and then you slip the
output through the slot. Now, sarl says that in this scenario,
with a sufficiently powerful instruction manual, the person in the
room would be able to simulate being able to understand
the Chinese language despite not actually understanding a single word
of it. The person is just an operator. They're just
blindly copying symbols from a rule book. They don't understand

(36:28):
what any of the symbols mean. So in the same way,
Cearle says that this gets extrapolated to any computer program
that would supposedly pass quote pass the Turing tests, which
we've discussed the turning test on the show before. But
basically it means to be able to have a text
based conversation with the human such that the human would

(36:49):
believe that the machine they were chatting with was actually
human as well. Can you can you fool a human
into thinking you're a human by talking to them through text?
And Searle says, it doesn't matter how convincingly the computer
simulates being able to have a conversation in any language.
It's still like the non Chinese speaker in the Chinese room.

(37:10):
It can't really understand what it's doing. It's only blindly
following instructions that create an illusion of understanding where true
understanding is impossible. Now, there have been tons of responses
to this scenario over the years, and I think we'll
come back to this towards the end of the episode.
But the idea is the thought experiment of imagining the

(37:32):
person in the Chinese room leads you to new knowledge.
It should lead you to the correct conclusion that it's
impossible for a machine to understand something, or at least
a machine interpreting formal instructions. Robert, I, I could almost
detect by the way you're furrowing your brow that this
this one's filling you with venom. Well, the the Chinese Room, Yeah,

(37:54):
um no, I mean I love it. I keep that,
I keep wanting to say something kind of snarky about
like just the human experience itself being you know, like
the Chinese room, that where there's so much that we're
doing that that we're we're not really understanding, We're just
responding to stimuli and giving back what the instruction manual
says we should give back. But then I do have

(38:15):
in a way articulated one of the main types of
responses to it. Yeah, but that it said yeah, but that,
in my opinion, like, this is the great thing about
a solid thought experiment and is in that it it
provokes conversation and subsequent sort of answers and critiques of
the thought experiments. Right, So, I guess in a minute
we are going to end up talking about sort of

(38:36):
formal classification systems for types of thought experiments and considering
how thought experiments might or might not be useful. But uh, there,
I can see that there are multiple ways that one
could be useful. Immediately, one could be useful in the
way it's intended, meaning it can prove what it sets
out to prove. Or it could also be inadvertently useful
in that even if it fails to prove what it

(38:57):
sets out to prove, it could make common misunderstandings clear. Right,
does that make sense? Yeah, like reveal ways in which
people's thinking is going wrong on a particular subject. Like
it's like saying, here is a scenario that illustrates a
way of thinking about this and then even if if
what it is presenting you with is incorrect, or has

(39:19):
some problems, or doesn't fully match up to um scientific reality,
or or just preconceived notions, then at least you have
you've created the model. You have, you have the model
on the table, and other people can come along and say, well,
you know, this is interesting, but what happens when we
put a hat on this guy, what happens when there
are two instruction manuals, what happens when you know the

(39:40):
ship of theseus also has a crew, etcetera. You know,
all the various complications are little tweaks that can can
change the model just a little bit. I think sometimes
thought experiments, even if they fail at proving what they
set out to prove, can be useful in the same
way that introducing terminology to a DISCUSSI can be useful

(40:01):
just because, like if you put an image to something
or put a name to something, that makes it easier
to understand what it is you're talking about. All right, Well,
on that note, let's take one more break, and when
we come back, we're gonna get more into this idea
of what is the thought experiment and indeed, where does
the term come from thank, alright, we're back. So in

(40:22):
looking at the history of thought experiments, you know where
you able to find the oldest one on a like
a like a cave wall. Uh No. But I mean
we kind of end up getting into a similar situation
when we started trying to think about this, because certainly
we know that thought experiments were employed by a pre
Socratic philosopher, so this has been before the life of Socrates,

(40:43):
before for seventy b c. And then thought experiments are
the things that were essentially thought experience were popular throughout
the Middle Ages, and of course came into their own
in the seventeenth century and the centuries to follow. The
term itself is often attributed one Ernst Mock, who lived
at eight through nineteen sixteen. He was an Austrian physicist

(41:05):
and philosopher. And they point this out because he used
the term, let's see, if I get this right, gadoncan
experimente uh. But it seems though that like it was
already in use by the time he used it, and
it may have derived from the Danish uh tunk experiment.
And then it turns out that Georg Lichtenberg through seventeen

(41:28):
ninety nine he discussed quote experiments with thoughts and ideas.
So funny, like all of these are coming after the advent,
you know, after Galileo, like Galileo and Newton, and people
had already been using these, As we said, they weren't
the first to use them, but they used them in
really profoundly influential ways in real science. Yeah, So it's

(41:48):
kind of like we're looking at three phases here. There's
the phase where people are actually calling it a thought experiment,
there's the phase where people are using them to great effect.
And ultimately, I think if we if you go back
further in time, you know, get lost in the mists
of of of earlier history. I think it's fair to
say that thought experiments are generally a more refined idea

(42:09):
of something that we just do as humans, and internal
simulation of of observed empirical data and processes, trying to
run an experiment in your mind given what you know, right,
and you know, I can imagine this is kind of
getting into the territory of our our other show, Invention,
which everyone can can learn about invention pod dot com.
It's a podcast about inventions and where they come from.

(42:30):
Subscribe now. Subscribe now, now, uh, seriously, stop and go
and subscribe. But but you know, you can imagine with
any of these inventions. This is even some of the
ancient ones that we've talked about, Like there is a
thought experiment level that is that is in play. But
I don't think it's a great stretch to imagine some
of these ancient inventors and inventive minds essentially engaging and

(42:53):
thought experiments. Oh well, yeah, I mean that's an interesting
way of putting it that you have to sort of
before you create a tool, you have to imagine what
would happen if you use something of a certain shape
in a certain way without having seen something like that
done before. Right. But then again, of course we go
back to what we said earlier about how just envisioning
an experiment you could carry out is not in in

(43:16):
and of itself a thought experiment, but it's still kind
of the roots of the thought experiment, right, Um, in
terms of thinking about like, well, what are some taxonomies
we can refer to for thought experiments. They're basically various
ways you could categorize thought experiments, but there's not really
a fully agreed upon standards so much obviously you can

(43:37):
categorize them by the discipline that they stem from. So
here's a bunch of physics thought experiments. Here's some quantum
physics thought experiments. Here's some some economic thought experiments. So
psychological thought experiments. You know, we could also break them
up based on their features, I guess, but I'm not sure,
really sure that does any good, because again, if it's
a cat or a dog or basilisk, it doesn't matter.

(43:58):
That's just some flavoring that's added to the little story
of the thought experiment. Well, I'm already seeing in the
examples we've discussed so far, one clear distinction that emerges,
which is the thought experiment that shows the absurdity or
contradictions inherent in some pre existing idea, versus the thought

(44:19):
experiment that demonstrates a new conclusion or show reveals new
knowledge based on premises you already accept. Right, And that's
that's where we come back to Karl Popper, who we
talked about briefly earlier. Karl Popper was an Austrian British
philosopher and professor who live nineteen o two through and

(44:39):
he this is this is basically how he divided up
thought experiments. He said, they're basically three types heuristic, in
other words, to illustrate a theory. Okay, so this would
be the kind that just helps clarify what you're talking about,
gives people something to picture. And you could argue that maybe,
I don't know, I'm not quite sure how Newton's cannon

(44:59):
would fit in there. Was that just to illustrate or
did he actually prove something using the image of the canon. Well,
you could also argue that it falls into the next category,
right critical against the theory, because he's kind of playing
with preconceived notions about how these things would work. Right, Well,
I guess yeah, it does challenge the idea that they're
different mechanics at operation in the heavens than there are

(45:22):
on the Earth. And now the Carl Popper's third category
then is apologetic in favor of a theory. Okay, So
you've got the kind that illustrates, the kind that challenges,
and the kind that argues in favor of Now, on
a similar note, you have Canadian philosopher of science James
Robert Brown, still still alive and kicking as of this recording,

(45:46):
and he's divided thought experiments into two major categories similar
along similar lines, constructive and destructive. Okay, those are the
broad categories, and then there are some some sub types
to the destructive category. So there's contradictive, this is a
thought experiment that points out a contradiction to a given idea.

(46:08):
Then there's paradoxical, so you have a thought experimentment here
that shows how a given idea is conflicting with a
commonly held belief. Then you have the undermine, or a
thought experiment that actively undermines an idea. And then there's
the counter thought experiment, a thought experiment that serves as
a rebuttal to another thought experiment. You know, I think
I generally would find that thought experiments are more often

(46:30):
sound when deployed as destructive or critical tools than as
constructive or apologetic tools. And I think this is because,
of course, as we know, thought experiments do not provide
new data or new evidence of anything. They only illustrate
logical relationships between things that we already know or already believe.

(46:51):
So they can take existing knowledge and use that to
extrapolate to new knowledge. But it's much easier to use
them in a way that's reasonable to demonstrate a contradiction
between existing pieces of knowledge. Or principles that the extended
version of the reductive ad absurdom. These are I think
some of the most powerful uses of thought experiments when

(47:12):
they when they have the power to clearly show that
things that you already believe or accept or are you
know bound to accept, are in fact self contradictory. Alright,
so let's go. Let's get down to one of the
questions that has often discussed your regarding thought experiments. Uh,
people say, well, do they really tell us anything? Oh? Yeah,
some people hate thought experiments. I think it really just

(47:35):
just riled up because it's like, oh, you know, it
seems like this navel gazing kind of thing, like, if
you're not going to go out and do physical experiments
in the physical world, what are you even talking about?
Why you know, why are you wasting your time? Armchair science?
Is is one of the criticisms is often thrown out
regarding thought experiments. But of course thought experiments have been

(47:55):
really useful in the history of science. As we've talked
about before, a lot of important advances in the history
of science have been before they were confirmed in fact
by physical experiments, were predicted by thought experiments. That this
is a very common feature, especially in physics. I mean
you could even say in fact that there there are
whole realms of physics today. It's probably what you would

(48:17):
call theoretical physics. You often hear this division of theoretical physics,
physics and experimental physics. Uh. There, there's all this stuff
in theoretical physics right now that we don't have a
way of testing with physical experiments yet. And you can,
you can kind of try to make your arguments one
way or another stronger about string theory or something like that,

(48:38):
but it just we we don't have a test for
it yet. So you could say that all of that
is in a way a type of mathematically elegant thought experiment.
But but if you go back and look at you know,
Newton and Galileo and all this, and certainly Einstein, there's
no denying that thought experiments have been extremely useful and
productive in the history of physics. But thought experiments can

(49:01):
sometimes also, as we've acknowledged, be confusing and misleading, even
though there are other times illuminating. A favorite of ours
on here is, of course, Daniel Dennett. You know, he
likes to highlight the different kinds of thought experiments that
try to leverage our intuitions into new discoveries simply by
tightly controlling the variables of an imagined scenario. And some

(49:21):
of the most famous thought experiments in history. Actually, I
think maybe confuse more than they illuminate. I don't want
to put words in his mouth, but I think Dinnett
would say this about Donald Davidson's swamp Man, which we
discussed in our show Thesist episode, or Searle's Chinese Room,
which maybe we should come back to now. So we
explain Searle's Chinese Room earlier, with the person exchanging the

(49:43):
symbols in the room, and the question of does the
person in the room who doesn't speak Chinese but can
simulate perfect conversational output in Chinese by following this instruction manual,
does that person really understand Chinese? And a lot of
people have thought, yeah, this is a powerful disproof of
the notion that computers could ever think, understand, or be conscious,

(50:06):
and a lot of other thinkers have been incredibly critical
of this. An example of a reply to the Chinese
Room that makes sense to me is what if what's
true of the part might not be true of the
system as a whole. So imagine again this person in
the room. The person in the room doesn't understand Chinese,
and thus the responses they produce are not meaningful to them.

(50:27):
But you could argue that the room itself, the set
of instructions, combined with the memories and sensory experiences and
logic that went into the creation of the instructions, and
the human operator and the pencil and paper taken together
perhaps do understand Chinese. And Cyle rejects this line of thinking.

(50:49):
One of the reasons is he says, you know, this
is a kind of illicit externalizing of thoughts, saying that
like paper could think, or a book of instructions could think,
but but I think like he's the person who put
this system together. You know, you are the one who
put a human inside a room as the metaphor for
a computer. Computers do not actually have a tiny human

(51:11):
inside them that's performing operations with opportunities to understand or
not understand. Likewise, there is not actually a little human
sitting inside your brain with the job of understanding or
not understanding inputs and outputs. Your brain is a system
in many ways. You might say that system of your
brain that produces your mind is more comparable to the

(51:34):
entire system of the person in the room, the room,
the instructions and all that than it is just the
person inside. I think the evidence is pretty clear that
the mind is not one thing, and there's no evidence
of an observer within the observer. The mind is at
the very least a system of information processing but also storage,

(51:55):
inputs and outputs, all working together. There's not there's no
evidence of a pilot inside who does all of the
final understanding. Right. That's rights as simple as it would
be to imagine that, you know, because it would reduce
whatever we're trying to figure out, would reduce it to
a person would get back into that that that kind
of you know, neolithic mindset. And so I think this now,

(52:15):
I certainly don't want to say that that I'm not
like casting expersions on John Searle. I'm sure he is
a very brilliant man, much smarter than me. And there's
been a lot more you know, complex back and forth
on this, But just to somebody who's right about this
a good bit, it seems to me like this is
one of those thought experiments that needlessly turns up confusion

(52:37):
just by bringing in a lot of unnecessary assumptions and
the connotations of the imagery you use in the thing,
like we've got a person inside a room that that's
making you think of analogies to a person sitting inside
the computer or an observer inside the observer in the brain. Now,
I I do take the problem of consciousness seriously. I'm

(52:58):
not one of those people who you know, would handwave
and say, oh yeah, consciousness is easy to explain. It's
just a you know, systems theory or whatever. But I
don't think the Chinese room proves machines can't think, or understand,
or have intentional or meaningful internal representations or be conscious.
I think that's still an open question. And to my mind,
the Chinese Room experiment is one of these thought experiments

(53:21):
that creates a lot of confusion by the hidden assumptions
it imports with its central imagery. I don't know, am
I being unfair? No? I think you're being being very fair.
I mean again, I come back to to certainly like
political cartoons as as a reference, you know, not that
not to reduce the Chinese room to something so you know,
ultimately kind of base. But there is a boiling down

(53:44):
of of a process there's a boiling down of a
of a problem that takes place in a thought experiment
like this, and then you do have to ask, well,
in reducing it to this model, what of the necessary
complexity is lost that is necessary to understand what's going on? Yeah,
I think that's exactly right. And I would say for me,
crucially it's the image of the person in the room

(54:07):
that's the especially confusing thing in this thing here, Like
what if there wasn't a person there? What if you
just instead said the room is a machine that takes in,
that takes in symbols and puts out symbols, then you're
basically not really changing much. You're just saying, well, it's
a computer, and then that's what we're talking about originally.
But anyway, so we mentioned Daniel Dennet. He's written extensive

(54:31):
criticism of the Chinese Room. I think this was even
the context of his coinage of the term. Intuition pump
is the title of one of his books, Intuition Pumps.
Uh dinn It writes, quote, Intuition pumps are cunningly designed
to focus the reader's attention on the important features and
to deflect the reader from bogging down in hard to

(54:51):
follow details. There's nothing wrong with this in principle. Indeed,
one of philosophy's highest callings is finding ways of helping
people see the four us did not just the trees,
but intuition pumps are often abused, though seldom deliberately. Of course,
dnn it himself has has played with thought experiments before.
Absolutely I'm instantly reminded of the it was almost kind

(55:12):
of a little short story he wrote about those that
are a robot with a human brain. Wonderful. Yes, the
where am I I think it was called? So dnn
it is as he says, they're certainly not opposed to
thought experiments, but he uh, he points out, I think
quite correctly that sometimes they actually confuse more than they illuminate.

(55:32):
Whether that's true of the ones he himself has put together,
it's it's hard to say. I mean a lot of times.
The benefits of these physics thought experiments, as we've been saying,
is you can eventually go out and test and see
whether they were on the right track or whether they
were confused by some you know, hidden assumption taken on board.
It's harder to do with a lot of these thought
experiments about say, the physical location of consciousness or something

(55:56):
like that. Uh So, one example from Dennett's book intuition
Pumps that we talked about in our Ship of Theseus episode.
You remember the Swampman of course, because it's essentially swamp
thing from the comic book, right. Yeah, So this was
an example of you know, dinn It explaining how intuition
pumps can go wrong. And again, intuition pumps are just
thought experiments that that rely on our intuitions that don't

(56:19):
like take specific data on board. Really, I'll try to
do very very quick. The example was this guy named
Donald Davidson. He was a philosopher. So he said, assume
lightning strikes me while I'm out walking in the swamp,
and it evaporates my body and I'm just gone. And
then meanwhile, it also strikes a tree next door, and
it rearranges that tree into an exact adom for Adam

(56:40):
copy of me with all my memories, and he calls
this creature Swampman, and so he asks, is that copy
really me? Davidson says, you know, is it really friends
with my friends even though it has never met them before?
Does it really know what a banana tastes like even
though it has never tasted or even touched one. This
was offered, I think, to interrogate the question of how

(57:04):
the history of an object is related to the identity
of that object. Is a thing that is an exact
copy of you, that behaves exactly like you, but hasn't
been where you've been and done what you've done in
what ways? Is that actually different from you? But didn't
responds to this story by saying, you know, this thought
experiment might not actually reveal all that much, And as

(57:27):
a point of analogy, he asks us to consider the
cow shark. So the cow shark again, is it's created
when a normal cow gives birth to an animal that
is adam, for Adam exactly like a shark that you
would find swimming in the ocean. And he asks, now,
is this newborn animal a cow or a shark? Oh,

(57:47):
but also take on board that it has cow DNA
in all of its cells. Now, a question like this,
it might do something useful, like it might help us
identify what features we think are important when we use
words like cow and shark. But it really doesn't reveal
anything about biology or about the world. You know, you're

(58:08):
not going to get new information about reality from it.
I think the best it could hope to do is
help us figure out what we mean by words, and
not to say there isn't value in that. But yeah,
that seems to be about all that it does. Yes,
so then it actually arrives at a claim. He says, quote,
the utility of a thought experiment is inversely proportional to

(58:28):
the size of its departures from reality. That's why he's saying.
You know, Swampman just doesn't seem to be all that
useful and understanding what what it means to be a
physical object like a person, because something like that is
never going to happen in reality. I also, and I
felt this way before too. I also feel like swamp
Man is just a little too complicated, Like just use

(58:51):
Star Trek, just say Cat to Picard teleports down to
planet X and then back up to the Enterprise. Like,
is then what happened when he hangs out with his friends,
what happens when he plays the flute, etcetera. Well, I
guess it's the same problem either way. But to answer
that question, you're using your intuitions, which are trained on
a world where that never happens. So your intuitions just

(59:15):
don't do much. They're there, they are not honed to
solving this kind of problem. Your intuitions are much more
useful in say, like combining premises about how things fall
and stuff like that, because actually you're quite experienced with
falling and you can combine that with observations about gravity
and stuff. Now, I don't I don't think uh. Dennett's

(59:36):
little proclamation there about the size of its departures from
reality is then again like a solvent that will that
will fix all the problems, because it can be very
hard to measure the size of a departure from reality
in any consistent way, Like does the Chinese room experiment
depart more or less from reality than Einstein imagining a

(59:57):
train traveling near the speed of light? Right? Because the
Chinese room, you could do that, I mean, maybe somebody
has done that. I mean, all you need is just
a person in a room and an individual on the
outside writing Chinese characters down right, I mean, you know,
and also speaking and being able to being able to
speak and write Chinese. Obviously you can't have just nonsense

(01:00:17):
going in. But that's the only two components, and we
could We could pull this off today if we needed to. Though,
I would say that the problem with the Chinese room
actually is not its departures from reality, as in, like,
it's not plausible that you could make a room like
this and put somebody in it, because you have a
determined if it's illustrating anything about how a posed machine

(01:00:39):
is thinking or not thinking. Right, the lack of its use,
I think is it's in its departures from the thing
it's supposed to represent. It's supposed to be an analogy
for a computer, but it's actually not a good analogy
for a computer because it's a room and a person
and some pencil and paper. That's just like they're not
the same thing. But with Swampman, yeah, they're all these

(01:00:59):
fan hastic ideas in it that don't match up with reality.
Whereas the ship of theseus is A is A is
so brilliant and and as and as to the test
of time because everybody can can associate with that, like
the upkeep of physical structures and devices, the constant replacement
of those things, the constant change to things that we

(01:01:22):
think have autonomy, like like ourselves or or sports teams, clubs, buildings, etcetera. Well,
the kind of chilling takeaway from from that distinction you
make between the ship of Theseus and the ship of
Theseus version as instantiated in Swampman is that maybe it
makes more sense to have to answer questions about the
meaning of identity as it refers to things than as

(01:01:45):
it does refer to people. Yeah, in many ways, it
is easier to think of people as things if you're
just gonna doing these kind of computations. I also want
to clarify that if you're more interested in the Chinese Room,
they're like a billion other classes of responses to it
you can go look up. Like one is that, you know,
you should really maybe think about putting that computer inside

(01:02:06):
a robot and then that would be more consistent with
the type of experience that a human has. And so
like what if you put the Chinese room in a
thing that could go around and look with cameras outside
and you know all that kind of So there are
just tons of different responses. While I don't find it
convincing on on what it tries to prove, I do
think it's one of these things that is at least

(01:02:28):
inadvertently useful for clarifying what people mean when they're talking
about this subject, because usually if you start asking something
like can a machine be conscious? You just don't even
have a foothold to start reasoning. Just where do you go?
It's just I don't know, yeah, because on one hand,
it's hard enough to know what consciousness is for us
and then to extrapolate what that would mean to a machine.

(01:02:49):
There's just no like, how do you feel in the
values on that equation? So I give it credit for that.
It it I don't think it solves the question, but
it does give you a first place to start climbing
where you can even can employ what it would mean
to solve this question. Now, to return back just the
idea of what is the thought experiment? What is in
a thought experiment? I do want to refer to just
a few ideas that have been pointed out by Dan

(01:03:10):
Falk and his Ian article Armshare science. Thought experiment played
a crucial role in the history of science, but do
they tell us anything about the real world? He points
out that John Norton, a philosopher at the University of Pittsburgh,
has argued that we shouldn't elevate thought experiments too highly.
They are essentially quote elegantly crafted arguments that bring vivid
pictures to the mind's eye. So the argument here is

(01:03:34):
that the thought experiments, as we've been discussing, don't produce
any new knowledge themselves, but rather constituted deduction of existing knowledge.
And he maintains that all thought experiments are are simply
restate can simply be restated. His arguments, like his challenge
is sort of rough challenges. You can bring me a
thought experiment, I'll just restate it as an argument, and

(01:03:55):
that's all there is to it. Well, I think he's
essentially correct that any good thought experiment can be restated
as a deductive argument, you know, with the kind of
the boring you know, logic class style logical premises. Right,
but thought experiments are useful because they're easier to remember,
they're easier to understand, and they give you pictures that
you can wrap your mind around, right exactly. They change

(01:04:18):
the way you think about something, and and that's ultimately
I believe the point. The counterpoint that is made by
James Robert Brown, a philoss for the University of Toronto,
who points out there like Okay, yeah, Norton, you may
be right, and he even says, I think Norton probably
could restate all thought experiments as arguments, but we don't
really work them out in our heads as arguments. We
work them out in the form of these thought experiments.

(01:04:40):
The cognitive process here because is much is much more
intuitive and less analytical thought experiments. Therefore, they transformed the
ad the analytical into the intuitive. What did we evolve
thinking for? What was it useful for? I mean, can't
be sure, but it really seems like what's likely is
not that, say, our boreal primates were trying to work

(01:05:03):
out analytical premises of an argument and say, you know,
premise one is no. I mean they were imagining scenario.
Is like thinking is useful for saying, Okay, if I
went down on the ground right now, what would happen? Oh? Yeah,
that's right. There was a leopard down there. So if
leopard and me on the ground, that that's not good.

(01:05:26):
Imagining scenarios is so much more natural and intuitive to
us than than formal syllogistic arguments. Now. Falk also points
out that there's a third possibility here. The third argument
presented by cognitive scientists Nancy Nercessian of the Georgian Institute
of Technology, As she argues that thought experiments are simply
middle mental modeling. If Falk provides a quote for her

(01:05:47):
from her in his article, quote, a mental model is
basically a representation of the structure, function, or behavior some
system you're interested in, some real world system that retains
its sensory and motor properties they you get from perception.
When we manipulate a mental model, she argues, we use
quote some of the same kind of processing that they
would use to manipulate things in the real world. So, yeah,

(01:06:11):
the idea here, it's it's the example that has often
put forth is if someone says, hey, how many windows
are there in your house? And then how unless you
just carry around that raw data in your head, the
way you solve that is probably to form a mental
image of your house or room by room, form the
mental images and then count the windows. But you had
to have looked at your house already, right, Yeah, you

(01:06:33):
can't just have just you know, uh, you know, experimental knowledge,
like you have to have some real knowledge. You have
walked through your house, you've seen your house, and then
and that's what you're using to reconstruct this this model,
on the other hand, it's worth pointing out that just
counting the windows in your house is probably a quicker way,
essentially falling back on the sign on scientific invest investigation

(01:06:56):
is going to be the clear cut method of solving
that particular question. Yes, especially if you care about getting
the right answer right. Yes, Uh, those sometimes, I mean,
I thought experiments can be very useful, especially in scenarios
where you're not super concerned with precision, but you're more
concerned with like the directionality of an answer. Like a

(01:07:18):
thought experiment can be quite useful in uh, just getting
a guess about whether a quantity in reality is going
to increase or decrease without knowing exactly how much it's
going to increase or decrease, you know what I mean. Yeah,
And then of course it to go back to black
holes for instance. Like that's an example of counting windows
in a house you haven't been to yet, by by

(01:07:39):
your by your understanding of everything surrounding whatever that house
should be, so that there there are cases where that
is the best method for trying to count the windows
in a given house. Well, it's almost like knowing like
what is the what is the tension and support strength
of glass? Now trying to imagine how big of a
glass house could exist before it falls over. You know,

(01:08:01):
you don't have to build that house. If you already
know some things about glass, you can run that experiment
on paper or in your head. But anyway, what I
think this all means is that we should build two
glass towers, one bigger than the other, and drop them
both but tie them together, and then shoot a cannon
off of them, and then drop a bag of cheese

(01:08:21):
from them. And so you basically you're you're arguing for
a shared cinematic universe of thought experiments. I mean, I
think most of them are in the public domain, So
this would be a great This would be a great
franchise for somebody to to pick up and run with.
You know, at this point, I think a good number
of the most famous thought experiments have at some point

(01:08:41):
had like an indie movie made out of them. You know,
there's got to be. I would be shocked if there
is not a Chinese room movie. Well, I'm sure we'll
hear about it from the listeners if there is one.
Uh So, there you have it, thought experiments, hopefully a
nice overview of what they are what they are not.
Some different ways of classifying them some different examples, both

(01:09:03):
from past episodes and some that we haven't really picked
up and looked at here on the show. But hopefully
this will this will be useful moving forward as we
inevitably encounter other thought experiments in our consideration of various topics.
What I hope this allows us to do is to
be more confident in dismissing the ones they're not useful, right, yes, yea,

(01:09:25):
to realize that they are not you know, they're not
holy scripture set in stone, that that that they can
be flawed. There in many cases they are flawed and uh,
but then that's also part of their usefulness is that
the flawed model can be presented and someone can say, well,
let's look at this, look at let's change something in
this model and see what happens. All right. Well, hey,

(01:09:45):
if you you want to check out more episodes of
stuff to Blow your mind, you want to check out, say,
for instance, the episodes we did on black holes, the
Ship of theseus, uh, any of these these various topics
we've referred to in this episode, Well you can find
them all. It's stuff to blow your Mind dot com.
That's the mothership, that's where you'll find them all. That's
where you'll find links out to our very social media accounts.
We'll find a tab for our store place where you
can buy merchandise with cool shirt design, stickers, et cetera.

(01:10:09):
It's a cool way to support the show, and another
way to support the show is to simply rate and
review the show wherever you have the power to do so.
Big thanks, as always to our excellent audio producers Alex
Williams and Tory Harrison. If you would like to get
in touch with us directly with feedback on this episode
or any other, to suggest a topic for the future,
or just to say hi, you can email us at

(01:10:29):
blow the Mind at how stuff works dot com for
more on this and thousands of other topics. Is it
how stuff works dot com. Ty Ty twa three propert