Collapse like a thief in the night

Yet what if history is not cyclical and slow-moving but arhythmic, at times almost stationary, but also capable of accelerating suddenly, like a sports car? What if collapse does not arrive over a number of centuries but comes suddenly, like a thief in the night?

Great powers and empires are complex systems, which means their construction more resembles a termite hill than an Egyptian pyramid. They operate somewhere between order and disorder, on "the edge of chaos", in the phrase of the computer scientist Christopher Langton.

Such systems can appear to operate quite stably for some time; they seem to be in equilibrium but are, in fact, constantly adapting.

But there comes a moment when complex systems "go critical". A very small trigger can set off a phase transition from a benign equilibrium to a crisis.
--Niall Ferguson