A quote from Lew Rockwell.

From his new book Speaking of Liberty:

In the absence of the capitalist economy and all its underlying institutions, the world's population would, over time, shrink to a small fraction of its current size, with whatever was left of the human race systematically reduced to subsistence, eating only what can be hunted or gathered. The very institution that is the source of the word civilization—the city—depends on trade and commerce, and cannot exist without them.