From “Life After Doom: Wisdom and Courage for a World Falling Apart” by Brian D. McLaren
The Roman Empire, Tainter explains, was especially effective at solving problems. Rome’s growing agricultural output led to population growth, and eventually the rising population needed even more food. The solution? Rome invaded neighboring nations, colonizing them and exploiting their land, labor (in the form of slaves and vassals), agricultural output, and other resources (such as precious metals, art, and knowledge).
Maintaining these colonial holdings, however, proved expensive for Rome, requiring ever-growing numbers of soldiers, garrisons, and communication and administrative systems. This infrastructure required ever-increasing taxes. High taxation often led to internal corruption, as the upper classes skimmed tax money for personal luxuries while the masses struggled for basic necessities. High taxes, corruption, and growing economic inequality led to increasing levels of social unrest, which required more domestic military policing and tighter social control, which were also increasingly expensive. Eventually, a shortage of soldiers required the empire to hire mercenaries who lacked loyalty to the regime. As a result, the cost of the military increased while its effectiveness declined. The spiraling cost of maintaining the Roman Empire at its peak level of complexity became too high and it began to falter. The collapse was hastened by fragmentation, invasion and looting by outsiders, insurrection and rebellion among insiders, and a declining population.