- [Instructor] What we're going to do
in this video is talk about two related ideas
that are really the foundations of economics,
the idea of scarcity and the idea of rivalry.
Now, in other videos,
we do a deep dive into what scarcity is.
But just as a review, in everyday language,
you could think of something is scarce,
a good or a service is scarce
if there's not enough for everyone.
Another way to think about it is
a scarce resource is one that is limited.
It is a limited resource,
and there's not enough to go around
because there are potentially unlimited wants from people,
so potentially,
potentially unlimited,
unlimited wants.
And we could think of a lot of scarce resources.
Oil would be a scarce resource.
There's a limited supply of oil.
And potentially, if oil were free,
there's an unlimited amount of people
who would want to use that oil.
And so a lot of economics is, well,
when you have a scarce resource,
like oil or land or housing,
how do you allocate those resources amongst people,
people who are demanding those resources?
Now, rivalry is a related idea.
When we think about the everyday word rival or rivalry,
you imagine multiple parties competing for something,
and that's essentially getting pretty close
to the economics definition of it.
Something is a rival good or a rival resource,
I'll just call it a rival good right now,
if, when one person uses it,
it limits the ability for other people to use it.
So one,
one person
consuming it or using it,
consuming it
limits ability,
ability
for others,
for others to use.
And there's a lot of examples of rival goods
and things that are both scarce and rival goods.
For example, if I were to put a nice, delicious cake
that could only serve four people in our office
here at Khan Academy, where we have 80 or 90 folks work,
well, you can imagine, that cake's going to be a rival good.
It's also a scarce good because many people,
many more people are gonna want that cake than
the amount of cake we have.
But when you look at what the definition of a rival good is,
every time I, if I eat the whole cake,
that's going to limit other people's ability to use it.
And economists will sometimes create a spectrum of
how rivalrous a good is.
So, for example, let me draw a spectrum right over here.
So on this line,
so on the left-hand side, I will call this highly rivalrous,
which is, they'll actually use that word,
but I'll just call this rival goods.
And then at the other extreme here, I'll say non,
non-rival,
non-rival good.
And at the left end,
it's pretty easy to come up with a bunch of rival goods.
If you're living in a place where housing is tight,
where all of the housing is taken up,
housing is often a rival good.
I live in the San Francisco Bay Area.
And when a house goes on rent, you'll have multiple people
who are competing for that house, or if it's going for sale.
And so when one person gets it and gets to live there,
well, that's going to make it hard
for other people to use it.
You could imagine, you know, land
in a lot of urban areas is a rival good.
You could imagine something like, you know, a cake,
especially if there's not a lot of cake to go around
at a birthday party.
Now, what would be the other extreme?
What would be a non-rival good?
Well, there are very few perfectly non-rival goods,
but there are things that are close to it.
Because at least relative to where people's,
where people are trying to use it today,
it seems like there's almost an unlimited supply of it.
One example might be something that's close.
I'm not gonna put it all the way at the end.
I'm gonna put air,
air to breathe
on Earth.
Now, right now it's a non-rival good.
When I take a deep breath, it doesn't make it hard
for you to take another simultaneous deep breath.
And actually, let me put a little qualifier here,
simultaneously,
simultaneously.
That's actually a key qualifier for a rival good.
So, for example, a hammer is also a rival good.
Because if I'm using it right now,
it becomes very hard for you to use it simultaneously.
Now, as I mentioned, air to breathe,
if I take a deep breath right now,
it doesn't make it any harder for you to take a deep breath.
But if you were to take a extreme circumstance that,
let's say that if we were in a closed room
with a limited supply of oxygen, well, then the air
might become something closer to a rival good.
So let me put it this way, air to breathe outside,
while here I'll put air in
airtight, or let me put oxygen in an airtight container
or airtight room,
oxygen
in airtight
room or maybe a room that is running out of oxygen.
Well, then every time I take a breath, it's gonna make it
harder for you to take a breath and vice versa.
There's other things like, well, roads are rival goods,
especially if we're talking about rush hour.
So let me put this right over here.
So let's call this the roads during rush hour,
roads during
rush hour.
The more people that are on the roads,
that it's gonna make it harder
for other people to use it simultaneously.
It will get all this traffic.
People won't even be able to get on the highway 'cause
there's so much gridlock.
But then you could imagine roads
in the middle of the night are non-rival goods.
If I decide to take a drive
at three in the morning on most highways,
it doesn't make it any harder for another person
to take a drive on that highway simultaneously.
So let me put it over here, roads,
roads at 3:00 a.m.
in most places is closer to being a non-rival good.
So I will leave you there.
These are ideas that we're going
to keep revisiting in economics.
But it's good to have a sense of what they mean,
and then it'll inform how we think about
allocating these scarce goods amongst folks
and thinking about how we allocate
these rival goods amongst various parties.