Review essay: Escape from Rome (2019)
Modern economic growth
Perhaps, the most pronounced fact in human history is the fact that economic growth over the past 250 years has been far faster than at any time before and has radically transformed our world, to the point where the living conditions of societies in the 18th century seem as distant to us as their standard of living was relative to nomadic cultures. This applies even to developing countries: life expectancy in countries like Mexico and China today is approaching 80 years, compared to 30-35 years for the most advanced parts of the world in the 18th century.
Why did it happen, and why did it begin in Northwestern Europe? This is one of the most interesting questions but also one question that appears to be fundamentally impossible to give a complete answer, given the inherent complexity of human societies. The book Escape from Rome, written by Walter Scheidel, a classical historian, restates a popular argument: Western Europe had uniquely intense degree of interstate competition which has produced the underlying conditions that lead to modern economic growth.
The argument of the book
Scheidel first observes in the book that over the past 2,500 years, Western Eurasia, in particular Europe, is a part of Afro-Eurasia that was particularly fragmented politically: While in East Asia, the majority of the population was ruled by a single entity most of the time, in Western Eurasia, it was only Rome that managed to unify the majority of the population of this region under a single state (Scheidel estimated that 80% of Europe’s population plus nearly 70% of the population of the Middle East was under Roman rule for centuries, in the case of Europe, no earlier or later empire remotely rivaled Rome, while in the Middle East, the Persian, Islamic Caliphates, and Ottoman Empires achieved similar levels of dominance in the proportion of the population subjected to their rule but they never achieved the same level of hegemonic stability that Rome achieved). He argues that other regions of the world were too underdeveloped to develop large empires (Americas and Southeast Asia), lacked the ecological environment to develop large empires (Africa), or typically had the tendency to develop large empires (Middle East, East Asia, Indian subcontinent).
He claims that the unification of the ancient (Mediterranean) world under Rome arose due to exceptionally favorable external circumstances for unification. However, it appears that is not the case: around 300 BC, during the beginning of Rome’s rise to hegemonic dominance, there were over 1,000 Greek city-states around the Mediterranean, hundreds of non-Greek city-states in Italy, Iberia, and North Africa, as well as several large states spanning the region from Iberian peninsula to modern Iran: such as the Carthaginian, Seleucid, Macedonian and Ptolemaic empires. Conquering and almost permanently politically unifying this world was not an easy task.
Instead, the Roman Republic achieved hegemony due to its bizarre institutional structure. Rome was under a state of wartime mobilization during the entire period from the 5th century BC to the 1st century BC. During these 400 years, Scheidel estimates that between 10% to 30% of its adult male population was enlisted in the armed forces, and it was officially at war over 90% of the time. Thus, Republican Rome was a society in permanent mobilization for total war for centuries, a culture that was without documented parallel in human history. By the first century BC, this military machine was already running out of external targets. That might explain why most wars during the last half-century of the Roman Republic were civil-war. These constant civil wars only stopped when Rome’s political institutions were re-organized into the Roman Empire. With the regime change, militarization declined, as only 2% of the adult male population of the Roman Empire was enlisted in the armed forces during the 1st and 2nd centuries AD, a period often called Pax Romana.
The author then goes on to explain in detail all the cases of later empires (such as the failure of the Eastern Roman Empire to restore the territories of the Western Roman Empire or the failures of the Arab and Carolingian Empires to attain the same degree of hegemony) that never achieved the kind of domination Rome had acquired in Europe and the Middle East.
I think that clearly describing this exceptional historical fact is the great innovation of the book: nothing quite like Republican Rome happened before or after. In fact, I might conjecture it was the political fragmentation across the ancient world that allowed a bizarre anomaly such as Republican Rome to exist. Many strange political systems have developed across the thousands of sovereign states in existence in the ancient Mediterranean world. From the radical regime of Athenian direct democracy to the unique structure of the Spartan constitution. After a few centuries, this plurality of sovereign states was reduced to Rome, the last state to survive a Darwinian selection process on military fitness. Ex-ante, one would not easily guess that such political unification would occur: other imperial city-states are rare and typically form much smaller empires, such as Late Medieval Venice, Milan, and Florence, or Classical Athens and Carthage.
Why interstate competition can generate economic development
Economists know that competition is good. In the case of interstate competition, it can be beneficial if the subjects of one State can move to another State at relatively low costs. States have to compete for subjects as subjects have what economists call low switching costs. Then, States are forced to compete for the provision of law and order, public goods, more competitive taxation rates; otherwise, their subjects/taxpayers will migrate to other States. This implies that States will tend to develop “inclusive institutions,” which in this case means the transformation of their subject population into citizens endowed with rights. This reasoning explains why city-state cultures such as Classical Greece and Medieval Northern Italy (which consisted of hundreds of small polities) tend to develop inclusive institutions.
However, this line of reasoning does not apply to cultures that feature multiple large states, as the switching costs become prohibitive. This applies to regions of the old world that featured multiple territorial states such as late medieval and early modern Europe, the middle east after the collapse of the Umayyad caliphate, and to the Indian subcontinent for most of the last 2,500 years. Pre-modern episodes of inclusive institutions and urbanized cultures, what Ober called modernity before the fact, are restricted to city-state cultures. I also recall Hansen (2006), who explicitly speaks of modernity as the moment when macro-states adopted the institutional features of city-state cultures. Competition of multiple large territorial states will result in higher levels of state capacity and military development. Given the high switching costs for their subject population plus the higher costs of travel in attending assemblies (in the case of elements of direct democracy), interstate competition will tend to occur without the development of inclusive institutions and the associated economic development from these institutions.
One important thing to note is that despite the development of inclusive institutions and their relative prosperity compared to other pre-modern societies (see Ober (2015) for more details regarding Classical Greece, Koyama (2021) cites recent estimates that put Northern Italy’s per capita income in the 15th century on par with Britain in 1800) what we understand as modern economic growth was not present in Classical Greece and Medieval Northern Italy. It appears that even the intense interstate competition in city-state cultures and the associated development of inclusive institutions are insufficient to generate modern speeds of economic growth, even though it creates more prosperous societies relative to other societies of their time.
An element that helps to explain modern economic growth compared to previous efflorescences is demographic size: more people means more potential ideas and a higher potential degree of division of labor. As Adam Smith has observed, the division of labor is constrained by the size of the market. In Classical Greece, the largest city-states, such as Athens and Syracuse, had citizen populations around 30,000 to 60,000 adult males. The Ancient Greek civilization had a population that reached a peak estimated around 8 to 10 million. Northern Italy had a population of a few million in the late middle ages. For comparison, by the mid 19th century, when modern economic growth had become a consolidated reality, Britain’s population was ca. 25 million, and Europe and its colonies had reached 300 million. It is plausible that the modest economic growth of the city-states in Ancient Greece and Medieval Italy compared to modern economic growth did not reflect a defective nature of the mentality and institutions of their societies, but instead that it was the fastest economic growth that was possible under the scope for technological sophistication that was feasible given the small demographic sizes of these societies. The first constitutional states with inclusive institutions and populations of tens of millions were the US, France, and the UK during the mid 19th century.
Scheidel argues that protectionist policies practiced by the mercantilist states in the early-modern period were a necessary condition for the development of modernity. Nothing could be further from the truth: by isolating local economies, protectionism reduces the degree of division of labor and hence, of technological complexity, that societies can support, which constrains economic growth. One of the main drivers of the massive economic growth that occurred over the past 200 years was the gradual dismantling of protectionist policies and the resulting integration of billions of people into the global economy.
Another important factor besides the demographic scale is the development of the modern scientific culture/Enlightenment. Joel Mokyr argued that the development of a scientific culture of constant technical improvement in all fields of industry distinguished the British efflorescence that began in the late 18th century compared to previous episodes of economic growth. Both factors are fundamentally related: before developing a conscious political ideology of inclusive institutions in the 18th century; inclusive institutions could only occur due to spontaneous competitive pressures in small city-state cultures. After the 18th century, they could occur in states of any size (like modern India, the largest democracy in world history with over 1 billion inhabitants).
Thus, the development of science and technology during the Enlightenment was not only in regards to natural sciences but also in regards to the use of reason in the development of social rules and institutions. That was the nature of the work of political philosophy and economics by figures such as John Locke, David Hume, Adam Smith, Voltaire, and Immanuel Kant in the 17th and 18th centuries.
The conscious application of institutional design of institutions has as its most influential 18th manifestation the US declaration of independence and its constitution. This event was a major event in world history because the US was likely to be the first consciously designed Constitutional Republic. While the US was inspired by the constitutions of previous polities, such as the ancient Roman Republic, the US constitution distinguished itself by the fact it was composed of written rules that its founding fathers consciously chose instead of evolving over the centuries.
Is European political fragmentation historically exceptional?
Scheidel argues that Europe is a unique major region in world history in terms of lacking the tendency for centralized state formation. Is it clearly so? Not really.
Consider the map below of the Afroeurasian world in 1400. This date was just before the Great Navigations and resulting European political domination of the world and the intellectual flourishing of Europe over the following centuries that produced the scientific revolution and the Enlightenment.
There is a contrast between Europe and East Asia, where a single polity, in this case, the Ming Empire, has subjected about 90% of East Asia’s population to its rule. But this contrast applies to other regions of Afroeurasia: in this map, there are dozens of West African states, the Middle East is divided into many states, while the densely populated Indian and Southeast Asian regions are also divided into many states.
Overall, the degree of territorial fragmentation of Europe, while higher than the Afroeurasian average, appears rather typical of the Old World at that time, and the tendency for large empires to form is only present in Central and East Asia. Thus, Scheidel’s thesis that the failure of Europe to re-unify after the Fall of Rome was a great divergence from the rest of the old world does not appear to be the case.
I suspect the particular tendency for large states to form in those regions is primarily due to the following geographical features: the Central Asia steppe corridor means that cavalry based semi-nomadic groups (like the Mongols) have the tendency to develop large states in these sparsely populated geographical terms, but these empires were small in terms of population (for example, it is estimated that France had a much larger population at the time than the Mongol and Timurid states depicted in the map). Scheidel also discusses another theory: that proximity of sedentary populations to steppe pastoralist groups would lead to large states’ tendency to form to protect these farmers from being plundered by the nomadic bandits. I find this theory unconvincing: it is not true that political fragmentation would produce a territory easier to invade; in fact, the constant interstate competition of politically fragmented civilizations increases military might and make them more challenging for an external power to conquer: for example, a coalition of tiny city-states in Ancient Greece successfully defeated the mighty Achaemenid Persian Empire in the 5th century BC.
In the case of East Asia, in antiquity and medieval times, its population tended to be highly concentrated in a compact region (the great plains in northern China), as this map is based on an ancient census of the Han Empire from 2 AD demonstrates. Scheidel notes that out of the 16 episodes of unified Chinese state formation, 15 occurred from the unification of the great plains. Thus, I also find Scheidel’s exact parallel of the Roman conquest of the Western Eurasian world and the unification of the Seven Warring States by the Kingdom of Qin to be somewhat artificial: in fact, Scheidel states that Qin was at war for one-third of the time during the gradual process of unification of the Seven Warring States (roughly 250 years), while Republican Rome, to build the degree of political hegemony it enjoyed during the Principate, was at war nearly 100% of the time over a substantially longer documented period (400 years). Thus, the two processes are not similar: the formation of a unified Mediterranean empire that ruled over 80% of Europe’s population only occurred once, while the unification of most of East Asia’s population under a single regime occurred many times in history (also, the Qin Empire was not the first such case: the Zhou empire appears to have already ruled over similar territories around 1000 BC).
Contrast that with European population density estimated for the early 19th century:
Zones of relatively high population density spread over thousands of kilometers and several islands and peninsulas. In chapter 8, which is, in my opinion, one of the best chapters of the book, Scheidel focuses on the importance of geographical features to explain why Europe and East Asia developed distinct patterns of state fragmentation. I find that geographical features are the most convincing variable to explain different historical outcomes since humans are the same everywhere; what changes is the environment in which they operate. This argument was already articulated in Morris (2010).
Overall, the degree of political fragmentation of Europe, in particular during the 17th and 18th centuries when modernity was being gestated, was lower than in many previous civilizations, such as the highly fragmented Classical Greek world, which was fragmented into over a thousand city-states.
In history, the analysis of counterfactuals relies on the capacity of the mind of the historian to simulate a historical world to a sufficient degree of resolution that allows plausible predictions when certain elements of historical events are re-written. I do not think that is possible: nothing in the universe is more complex than human history, being the result of the interaction of billions of human minds with their natural environment, and its a degree of complexity that is far beyond the capacity of a single human mind to simulate. Thus, I do not think counterfactual historical speculation is much more than a form of entertainment.
It is true that every claim of the importance of a particular historical event is a counterfactual claim. Still, this form of counterfactual claim does not try to imagine exactly what would be the consequences of the absence of this historical event. For example, the claim that the 18th-century developments of the steam engine were important derives from the fact it is a technology that was widely used for centuries after its introduction.
I agree with Scheidel’s thesis that the Fall of the Roman Empire was a necessary condition for the historical development of modern economic growth in Europe. In fact, before the rise of Rome, significant advances towards modern science were made by the Ancient Greeks, such as the major philosophical contributions of Socrates, Plato, and Aristotle, and developments of mathematics and science by people such as Thales, Euclid, Archimedes, and Hipparchus. Given that less than 1% of the publications of antiquity have survived, their surviving documented advances towards modern science represent an impressive run for a civilization that likely never surpassed a population of 10 million.
After Rome dominated the Ancient Mediterranean, in part thanks to its vast supply of cheap military labor compared to the scarce and expensive Greek soldiers (as Scheidel points out, Roman soldiers were paid a silver stipend between 1/3 to 1/6 of the typical pay of Greek soldiers, a reflection of how much more economically developed the Greeks were at the time), the Western Eurasian hemisphere was plunged into a dark age in terms of intellectual development. It was only long after the fall of Rome that Western science and philosophy picked up where the Ancient Greeks had left it.
But, for me, the main conclusion from the book is how anomalous Rome was a historical political system, instead of the thesis that is explicitly advocated by the book that the political unification of Europe should be understood as a natural consequence of mature civilizations and that its political fragmentation after Rome’s fall was a sort of “great divergence” from the rest of the world.
Instead, I see modernity arriving in the 18-19th centuries as the result of thousands of years of historical processes in Western Eurasia. It should be first noted that both writing and agriculture were developed first in Western Eurasia than in any other region of the world, giving the region a chronological advantage in philosophical, technological, and scientific development. Also, the geographical features of Europe and the Mediterranean, with vast coastal areas to enable sea-trade (as trade by sea was nearly 100 times cheaper than trade overland before the development of modern railways and trucks) and geographical features that encourage the development of multi-state geopolitical systems, were always factors that conspired in favor of that region in the achievement of higher levels of economic and military development than other parts of the world.
The reason why modernity arose in Northwestern Europe rather than, let’s say, the Mediterranean basin, is perhaps due to historically contingent events: the division of the Mediterranean into Christian and Muslim worlds after the fall of the Roman hegemony meant that large scale sea-trade development concentrated along the Atlantic after navigation technology improved. Thus, regions with Atlantic access had a geographical advantage after the 15th century, as described in the map of registered ship logs of the 18-19th centuries:
This geographical advantage meant that the center of intellectual production was located in Northwestern Europe when the intellectual development of Western Eurasia culminated in the Enlightenment.
Goldstone (2002), Efflorescences and Economic Growth in World History: Rethinking the "Rise of the West" and the Industrial Revolution
Hansen, Mogens Herman (2006), Polis: An Introduction to the Ancient Greek City-State
Koyama, Mark (2021), Counterfactuals, Empires, and Institutions: Reflections on Walter Scheidel's Escape from Rome
Morris, Ian (2010), Why the West Rules-For Now
Ober, Josiah (2015), The Rise and Fall of Classical Greece