"Civilization emerges with complexity, exists because of it, and disappears when complexity does.

Complexity is the base of civilization, and civilization, by definition here, can disappear only when complexity vanishes. It may be true that specific polities can rise and fall within a civilization, but political complexity itself must disintegrate for civilization to disappear.

For this reason the study of rising and falling complexity serves as a monitor of the phenomenon termed civilization..."

Joseph Tainter - The Collapse of Complex Societies.