Bryan Ward-Perkins in The Fall of Rome: And the End of Civilization spends a great deal of time on the archaeology of the Classical and post-Classical world. But, he also devotes only somewhat less space to the historiography of the study of the Roman Empire, and Late Antiquity. That is because the study of the past is not just the study of the past, but it is the study of the concerns and values of the present. We look through the dark mirror to the past, and in it we see our own outlines. Similarly, science fiction which purports to be a projection of the future is often nothing much more than a retelling of the present in shinier garb. This reality of history, its reflection of the prescription of the present despite the conceit that it is a description of the past, needs to be kept in mind. It is not a failing which pollutes the whole enterprise, it is a reality which must inform our interpretation of it. The study of Rome is a study of what humanity was, but it can not help but also reflect and define what we wish to be, by comparison and contrast.
But before I go on, a minor mea culpa. After further research and correspondence I believe that I extrapolated too far from lead concentrations in Greenland ice caps in a previous post. Though I still believe that it is a good reflection of the decline in proto-industrial vigor in the Western world, I do think that distance from China means that we do not have a good gauge on any comparisons between 0 AD and 750 AD (the later date being the apogee of the Tang). Though I do note that world population estimates seem to be somewhat lower for 700 than 0. But these are not precise estimates, so they need to be taken with a grain of salt. Chinese census records indicate that Tang population was higher than that of the Han, while it seems plausible that the Arab Imperium of the 8th century resulted in a higher population for the regions under its purview than during antiquity. Therefore to make the "math work" one can reasonably assume that the population in Europe was far lower.
Additionally, to clarify my points from the previous post, I was presenting a description of the decline, not any allusion to the causes of the fall. And, my argument was that the rate of decline was far greater after the fall of Rome, not that there was no decline from the Principate to the Dominate. Though my opinions are not particularly well informed or strong, I would hazard to bet greater per person production during the Antonine period of the mid-2nd century than the relatively quiescent epochs of the 4th century. My argument is simply that in terms of economic production the 4th century resembles the 2nd far more than it does the 6th in the Roman West. The world of Procopius was further from that of Constantine than that of Constantine was from that of the Antonines, despite the fact that Justinian's Byzantium perceived itself to be (and rightly) simply a continuation of antique Rome.
The argument of The Fall of Rome which is powerful and persuasive as a description is fundamentally a material one. Political unity within the Roman Empire decreased the fixed costs of production (e.g., no need for city walls, no political boundaries imposing extortionate levels of duty, etc.). Rome was the Western world's first free trade zone where military conflict was ended by the imperial monopoly on force. This resulted in gains in wealth due to the economies of scale and classic Smithian productivity increases through specialization. Ancient Rome was not a consumer society characterized by eternal expectations of growth, but neither was there an expectation of collapse and regression (e.g., "The Eternal City"). I find the Malthusian logic of biology powerful in that greater productivity should be swallowed up by population increase, so that over the long term average well being for most humans has been approximately the same (increased aggregate wealth coexisting with the same per capita wealth). But there are many qualifications within that statement; the long term may actually have been longer than the course of the empire, suggesting that Rome never attained Malthusian equilibrium.
To support his proposition about material prosperity Bryan Ward-Perkins recounts the quality and number of pots and amphorae, as well as extensive archaeological evidence of a dense network of cities all across the Roman Empire. And though the average Roman peasant did not avail themselves of the consumption of the broad upper orders, they were at least free of the fear of marauders and enslavement by foreign peoples. One might respond here that they were subject to grueling taxation, but this is fundamentally a different argument. Modern examples seems to imply that high taxation is preferable to an anarchic order of no taxation and no services (e.g., Afghanistan). Bryan Ward-Perkins makes a compelling case in The Fall of Rome that the economic and political order of the Western Mediterranean and Northwest Europe regressed back to a pre-Iron Age level of complexity in the two centuries after the fall of Rome! In other words, the "Dark Ages" saw the unraveling of a set of organically developed norms and connections which had matured from the 5th century B.C. onward. A 1,000 year old civilization expired, as defined by the innumerable threads which had bound together the Western Mediterranean, Gaul, and Britain.
But there looms over this argument aspects which are just not material, but also normative. When alluding to literacy we obtain here a case where the material and normative intersect. By various means Ward-Perkins argues that rates of literacy were far higher during the period of the Roman Empire than after. It is famously well known that across the centuries of Rome it was not until 518 that an Emperor donned the purple who may have been illiterate (Procopius is not entirely reliable on matters factual when it comes to the family of Justinian!). In contrast, Dark Age princes such as Charlemagne were often illiterate. The most evocative and persuasive component of the argument in regards to penetration of literacy is that graffiti and casual scribbling are legion from the Roman period, but far rarer afterward. There is even documentary evidence that most priests during this the Dark Ages were functionally illiterate, with a substantial minority being totally illiterate (i.e., they could not sign their own names to documents).
So what that 10% of Western Europeans in 400 may have been functionally literate, while only 1% in 700 were? The "what" is that the penetration of literacy allows for a critical mass to develop for a particular form of cultural discourse. A fundamental aspect of the Classical World is that it developed out of a world of citizens. This does not mean that it was a democratic world. Rather, it means that a broad expanse of the populace was vested in the political order, whether in an Athenian democracy, Spartan oligarchy, or Roman republic. Only 100 years into the Empire were emperors actually called Emperor. Rather, they were Princeps, "First Citizens." The false conceit of the Roman Empire was that it was a restoration of the republic. Rome never had kings, and the slide toward explicit and formalized autocracy and despotism was gradual. The early republican army was one of freeborn citizens, and even after the Marian reforms which opened up the army to the proletariat the Roman legions were draw from the citizenry. Between the era of Augustus and the 3rd century the military became progressively less Italian, but it remained Roman, with only auxiliaries derived from barbarian people who were not citizens (after Caracalla granted citizenship to all freeborn Romans barbarian would mean someone from outside the imperial frontiers).
This alien world of emperors, slaves, and gladiatorial battles was nevertheless populated by familiar figures. There were philosophers and civil servants, city councils and a professional army paid in coin or salt. What was fundamentally alien is that it was 'pagan.' This is to some extent a catchall term which developed relatively late in history (in the Greek-speaking world pagans were termed 'Hellenes'), but it reflects the view that the old religion of the West was alien in a deep manner from what came after. Until recently faiths like Christianity, Judaism, Islam, Buddhism, and Hinduism were termed 'higher religions.' Today such judgmental terminology is less common, and they might be classed together as 'institutional religions,' or more more colloquially 'organized religions.' Often the term pagan is used to encompass the faiths outside of the Abrahamic religions, but because of the pejorative connotations of pagan this is probably not advisable.
The critical aspect which I think needs elaborating here is that in regards to the relatively seamless coherency and integration of all aspects of religiosity, high and low, and ritualistic, mystical, and philosophical, there is a qualitative difference between the institutional religions, and the older traditions. The ancients had ethical philosophy, they had rites, and they had mystical and ecstatic communal worship. What they often did not have was an organized system which packaged all these aspects together. If Constantine had fallen at the battle of Milvian Bridge then the West may not have become Christian, but it would not have remained pagan in a way which we understand it. The exact nature of the organic development of an institutional religion varies across civilizations, but it seems that a complex culture invariably demands a religious system which binds together various sentiments across elements of society. This is clear in the rise of solar religion in the late 3rd century, and points to the fact that in the 1st millennium all civilizations were moving toward a system where an institutional religion with metaphysical grounding anchored and gave legitimacy to the body politic.
But is this enough to differentiate us from the Romans and align ourselves with what became Christendom? Bryan Ward-Perkins observes that the study of Late Antiquity is rife with a fixation on cultural change in the domain of religion, with a neglect of the material and political dimensions of life. In particular there is much attention paid to ascetic religious figures who were instrumental in transforming Roman Christianity into Medieval Christianity. Granting the materialist argument (which even the doyen of Late Antique studies, Peter Brown, seems to do in Through the Eye of a Needle), are the cultural changes of Late Antiquity which make the world of Europe more familiar stark enough to make that age truly the seedbed of recognizable modernity?
It is critical to note that Late Antiquity lives on genealogically. The modern British royal family can trace descent back to at least the 8th century kings of Wessex. The dispossession of the Roman elites was such that despite the persistence of eminent families with roots in the late Classical period across Europe at the local level it is difficult to validate any European royal genealogies before the early Dark Ages. The modern nation-states of Europe also date back in their embryonic sense to this period. And critically one must distinguish between the Dark Ages from the High Medieval period. The latter phase saw a reemergence of social complexity, in particular in northern France, southern England, and the Low Countries. The Aristotelian Renaissance illustrates that after 1000 A.D. Western Europe began to rouse itself from its intellectual slumber.
But all that notwithstanding for me the critical aspect to emphasize is that the Germanic elites of the post-Roman Western European world were fundamentally military gangs; warlords and their underlings. This is not atypical. Rather, this is the normal state of pre-modern societies. And in this way it is fundamentally alien to the modern sensibility. The lords of the post-Roman world were of the same category as anax of Mycenaean Greece. Their profession was war, and their cultivation was of the sword. Though the Roman world was militarized, in fact most of the Imperial expenditure was on the legions, its elite was fundamentally civilian in orientation. Roman aristocrats were often military leaders, but more universally they defined themselves as being cultured and refined in relation to the common. No Roman could rise to a status of prominence without being literate, and the established nobility was educated in classical literature and rhetoric. This is not entirely surprising, as for several centuries the Roman world was characterized by peace, and high status was not likely to be won through feats of martial prowess. A similar process seems to have occurred in early modern Europe, as the military elites who were often the descendants in spirit if not genealogy from the post-Roman Germanic warlords began to cultivate their manners and fashions to signal their gentility. Part of this is due to the same decline in violence which characterized the Roman world. But it is also perhaps a response to the rise of firearms, which made aristocratic cavalry vulnerable on the field of battle. The civilian orientation of the Roman aristocracy is similar in many ways to that of China, where dynasties founded by generals nevertheless marginalized the military over time.
All of the above is why I state that my agreement with Bryan Ward-Perkins' contentions are to some extent normative. I feel that a brutal Classical Roman autocrat such as Marcus Aurelius is more modern than a brutal Dark Age autocrat such as Charlemagne. Then again, some of Aurelius' self-serving thoughts are preserved for us in his Meditations, while Charlemagne was an illiterate whose character is filtered through chroniclers. Charlemagne may have been the defender of Roman Christianity, but he was an exemplar of Romanitas in the same manner that the Democratic Republic of Korea (North Korea) is democratic (for example, he was an open de facto polygamist). The American republic was founded as a republic. Granted many of its institutions evolved organically from English common law tradition, but it is clear that the injection of ancient political theory revitalized the organization of Western nation-states. The Napoleonic Code draws inspiration from the rediscovery of Roman law. Ultimately it strikes me that the modern world manifests many of the structural features of the Roman world, with the Dark Ages being an unwinding from which the West only slowly recovered. Your mileage may vary, but that says more about differences in values among contemporaries, than it truly does about the factual assessment about the shape of the past.