The Expansion Factor is the simple rule of Civilizations: If you do not expand you die. Simple and example is Rome. The Roman Empire after a certain point decided it had conquered all the world that was important. It then built Hadrain's Wall. The wall was a metaphor for stopping growth. Now the expansion factor says that if a civilization stopps growth, it can only go backwards, their is no stalling. Kindof like a plane. Thoughts?