Crux of The Trajectory of Empires by John Michael Greer:

  • “The fall of civilizations takes place through a process [of] catabolic collapse”: when the economic activity required to maintain the empire overshoots its dwindling resource base.
  • The economic cost of maintaining an empire tends to increase over time.
  • The resources are always limited, and usually suffer under-investment because of the extraction of wealth up the imperial pyramid.
  • As this process proceeds, the empire must repeatedly shrink to fit its shrinking resource base.