I was wondering if it is possible to run a country based only on domestic economy and not to enter the world economy. Basically, if certain economy of a certain country fails and poses threat to world economy, can other countries seal off their economies and still function with sustained growth and flourishing markets based on domestic economy itself?
I know this a naive question, but I tried to find an answer on on the internet and didn't get a satisfactory answer.
It depends on what you mean by "sustained growth" and "flourishing markets".
Clearly the Earth as a whole is a big market. If you do not look at human made borders: the global economy is currently growing and some would say it is flourishing. There is no physical reason why this could not be done without the borders.
There are areas where the current technology cannot support the current population without outside help. An example is the heavily industrialized North Korea (which seems to motivate your question) which gets large amount of aid in food from the UN.
Yes. Sort of. A closed economy can theoretically flourish. But not as much as if were more open. The more trade that occurs, the more prosperous the trading partners will be. Approaching the square of the total amout of available trade.
Metcalfe's Law quantitatively models this answer:
$$ \Theta(n) = \frac {n(n-1)}{2} $$
where $\Theta$ is the number of connections within a network and $n$ is the number of nodes. The total value of the network can be thought of as the aggregate combined real GDP of the included sub economies.
So the more economies that trade with the subject economy, the value of the entire network asymptotically approaches $n^2$.
$$ \lim_{n \to \infty } \frac{\Theta(n)}{n^2} = 1 $$
A network modeled by Metcalfe's Law
The US and Japan rely heavily on other countries for their economy, as does every single economy on Earth. Say you put a wall around a flourishing city; nothing in, nothing out. Everyone will die. It's that simple. Expand this any way you like. It is basic physics. An organism can only maintain itself via material from outside itself, whether that is sunlight and soil or imported consumer goods. Even the ground we walk on is replenished by volcanic activity. And an organism must expel waste, whether this waste is gas or a glut of government-subsidised soy beans or even the trillions of tons of garbage that "First World" countries have polluted their own and poorer countries with. The cold hard fact is, no country can succeed unless
1) it is small or lucky enough to have a large amount of unused land/resources which are not being used by the population.
2)it has something that people in other countries want.
3) other countries are willing to supply that country with (at the very least) raw materials
Even in the early days of e.g. Europeans' colonisation of North America, the home countries were fundamental for currency and goods. Millions of animals in Canada were slaughtered for money from outside. The Gold Rush would have meant nothing if there was no-one to give it to in exchange for products. Human culture is now so large and so voracious that we will eventually (and much sooner than we think) get to the stage where we are basically living in one, sealed town called The Earth. Life managed to survive for billions of years because it never ran out of resources. Humans are not that efficient.
