This episode is about whether things continue to exist
[finger snap]
when you're not observing them.
[electronic theme music]
[theme continues] Much like our friend, Rene Descartes, all the way back in episode one,
you may have wondered, at some point in your life, whether the physical world is
really /real/.
And in 1710, the Irish philosopher, Bishop George Berkeley
decided that the world did not exist.
[record scratch, crickets]
Pepper: "That's a bold strategy, Cotton, let's see if it pays off for 'em."
Berkeley was arguing against the pretty intuitive position that there is a physical world independent from us:
things in the world exist and we pick up on them through our sense organs.
By the way: Berkeley ["Bark-Lee"]
"Bark Lee."
Not "Berk-Lee,"
even though Berkeley ["Berk-Lee"] was named after him.
"Bark-Lee."
So, think of it like this: when you observe something like a banana,
you say that it has some properties --
it's yellow, it's solid, it's curvy and so on --
the properties which you observe.
And you also say that there is a substance, there is a physical thing distinct from us
to which those properties belong, which we know about because we can detect those properties.
Now, the properties themselves don't exist independent of us,
like, bananas aren't /really/ yellow, they reflect certain wavelengths of light which we interpret as yellow,
and if we had different kinds of eyes, then we'd interpret them as some other color.
They "yellow-ness" is just in here.
Properties don't exist, unless they're being observed by someone.
But, what is "the substance?"
What is a banana that doesn't have any properties?
Nothing, right?
Now, try and imagine something that exists independent of any perception of it.
You can't, because as soon as you try, you think of some properties,
and properties don't exist unless they're being observed.
Like, I'm imagining a table, and it's brown -- wait, no, it's not brown
because nobody's there to see it --
and it's kind of, this sort of height --
wait, no it doesn't have any height because there's no one there observing it --
And when you say, "The table exists independently of me,"
for example, because it's in the other room,
then what you really mean is, "If I were to go into the other room,
I would experience the table."
But if objects are just their properties, and the properties only exist in our heads,
[Matrix theme in background] then there isn't an actual physical world distinct from us.
[theme continues] There's just us
and our ideas.
So things don't exist unless they're being perceived.
This was Berkeley's mantra: To be, is to be perceived.
The physical world
isn't real.
Kid: "There is no spoon."
[electronic theme in background] Okay, so far so crazy,
but it's kind of difficult to accept that, when you leave your house to go to work in the morning
the inside of your house stops existing until you come home.
Luke: "That's impossible!"
But Berkeley didn't mean that it literally disappears as soon as you turn your back.
What he meant was that, for it to exist in the first place
means that it's being observed.
To him, the idea that something existed without being perceived just didn't make sense
because something that isn't being perceived doesn't have any properties
Luke: "Nooooooooo!"
Okay, would you stop freaking out if I told you that there might be some way 'round of this?
For starters, we distinguish between appearance and reality.
We say that the world can sometimes /appear/ one way, but in /reality/ is actually another way.
Since Berkeley thinks that there is no "real world" independent of our perceptions,
he's committed to saying that hallucinations and dreams are as real as anything else.
So, an elephant that you see in your dreams is as real as an elephant you see at the zoo.
And, if that sounds like a step too far, then maybe there's something wrong with the theory.
Also, it seems like if we get our perceptions of the world wrong, then the physical world can actually impact us.
Like, suppose I don't see that there's a car coming and I step out into the road.
It must exist independently of me because, even though I don't see it, it still knocks me down.
[car horn honks] [jaunty music] "Oh!"
Berkeley thought he had a way out of this, and since he was a bishop,
it's kind of unsurprising which route he takes.
Berkeley said that God guarantees that everyone's perceptions cohere.
So, I don't perceive the car, but the driver perceives me,
and God guarantees that the car kills me because, otherwise the driver would be extremely surprised
when I phased right through his dashboard.
This answer has some issues, though.
Obviously, it isn't going to work if God doesn't exist.
And, what if I'm fatally struck by lightning in the middle of nowhere, so fast that I don't even perceive it.
Whose perceptions is God guaranteeing then?
Or, what if I take LSD, and my perceptions of the world are altered?
Is God the one that guarantees drugs work?
So, Berkeley has some questions to answer.
Maybe the physical world is like certain concepts in mathematics: we can't prove it, but
it's very explanatory if we believe in it.
It's a pretty interesting theory, though, right?
gif: "Pew!" Olly: Still, pretty eye-opening.
gif: [whooshing sound effects]
What do you guys think? Does the physical world exist independent of our perception of it?
What are things like without any properties?
Leave a comment with your questions or suggestions and we'll answer them at the end of next video.
Favorite, share, tell your friends about PhilosophyTube
You can also follow us on Twitter and when I observe the video statistics,
it would be nice if some "likes" existed.
[TARDIS whoosh]
Let's see what you guys had to say about morality and the future.
NineFactorial said that we can have obligations to future generations because we're meeting them every day;
they're being born all the time.
Mmmmm... Nice try, but of course as soon as somebody's born, they're no longer a future person
they become a /now/ person.
So, the question of whether or not we can have moral obligations to /future/ people is still open.
Jim Groth said that we should preserve the environment because we have an evolutionary duty to our children
to make sure that they'll be alright.
Yeah, that's a pretty good point. I would say, though, that's more of a practical duty than a moral one
and what about those of us who don't want or can't have children?
Is it okay for them to mess up the environment?
In our one hundred subscribers celebration video,
I asked you whether you would sign up to live in a virtual reality that would make you much happier
if you didn't know that it was fake.
Liam Sloggett said that we don't know we're not living in a virtual reality right now,
so why not sign up for a nicer one?
Michael Ruigrok said that he wouldn't go for it,
because of the value of things like integrity and sacrifice, not just happiness.
But Max Gisborne came out with a very nice reply, and said
"Do you not just value those things because they make you happy?"
This lovely person -- I'm so sorry, I don't know how to pronounce your name
and no amount of googling would help me --
but they asked if I recommended any other YouTube channels about Philosophy.
I guess I'd recommend, uh, PBS Idea Channel and Vsauce,
but when they do philosophy, they tend to touch on it lightly, rather than dive right in.
That's one of the reasons I made this channel, actually, is 'cause there seemed to be a need for it.
I'm also sorry that your textbooks are boring,
I kind of know how that can feel. When I started out, it was my teacher that made a difference for me,
not the textbooks.
If there's anyone else in your class that would like these videos, then do tell them.
The more the merrier.
BBrucker2 asked if there was a button that I could press
that would make it look as if I had twice as many subscribers as a I do,
would I press it?
I. . . don't think I'd go for it. I mean, it's not really about the numbers, is it?
I - I care more that people enjoy it than about where I am in the "Top Ten Subscribed Channels" list.
Background music: "1, 2, 3, blast off!"