Every time history repeats, the price goes up

Rome was sacked by Gaul invaders in 390 BC, and in the 210s BC the Carthaginian general Hannibal wreaked havoc on the Italian Peninsula. Yet the Roman Empire survived and flourished over subsequent centuries, only falling to raiding ’barbarians’ more than five hundred years later.

Why did the early setbacks not lead to the fall of Rome while the later ones, when the Empire was at its grandest, did? The answer comes down to “complexity” and “energy”.

“Complexity” refers to the degree of a s...