Why civilizations die?

In her book, The Watchman's Rattle, subtitled Thinking Our Way Out of Extinction,

Rebecca Costa delivers a fascinating account of how civilizations die.

Their problems become too complex.

Societies reach what she called a cognitive threshold.

They simply can't chart a path from the present to the future.

The example she gives is the Mayans.

For a period of 3,500 years between 2,600 BCE and 900 CE,

they developed an extraordinary civilization spreading over what is today,

Mexico, Guatemala, Honduras, El Salvador and Belize, with an estimated population of 15 million

people. Not only were they master potters, weavers, architects and farmers, they developed an

intricate cylindrical calendar system with celestial

charts to track the movement of the stars and predict weather patterns. They had their own unique

form of writing, as well as an advanced mathematical system. Most impressively, they developed

a water supply infrastructure involving a complex network of

reservoirs, canals, dams and levees. Then suddenly, for reasons we still don't fully understand,

the entire system collapsed. Sometime between the middle of the 8th and 9th century,

the majority of the Mayan people simply disappeared. There have been many theories as to why it happened.

It may have been prolonged drought overpopulation into Nissan wars, a devastating epidemic,

food shortages, or a combination of these and other factors. One way or another, having survived for 35

centuries, Mayan civilization failed and became extinct.

Rebecca Costa's argument is that whatever the causes, the Mayan collapse,

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