The smallest possible explanation for the economic calculation problem

I’ve been reading some Hayek lately and one insight significantly altered my perspective on economics. When he discusses the division of knowledge, he states that the situation in a free country is not of an economy, but of the mutual coordination of millions of individual economies.

It is incorrect to compare a socialist economy to a free market economy. There is no free market economy, there is a free market between economies. It is the fact that all individual economies are cooperating with each other through markets that allow them to organize a complex production structure. A socialist economy only has one economy, even though it may try to clear prices for final goods.