At the end of his monumental study titled “Decline and Fall of the Roman Empire” Edward Gibbon discusses the question of whether what happened to the ancient empire could happen in modern times, that in the late 18th century, when Gibbon was writing. His answer is that it could not; new hordes of barbarians couldn't destroy the civilized world because of gunpowder, cannons, modern armies and the like.
It is clear that Gibbon saw the Roman collapse as mainly a military event: the Romans were overwhelmed by one wave of Barbarians after the other. But, like many other historians before him, Gibbon chronicled events without normally interpreting them in the sense we give today to the term - that is finding social, economic or political reasons to explain what happened.
Gibbon, living in the thriving and expanding world of 18th century Britain, just couldn't see that there was much more in the Roman collapse than a simple military problem. It would take time for historians to see the collapse of the ancient world as something related to our own destiny. With collapse impending, or perhaps already started, we can start seeing that the Roman times are a foggy mirror of our times.
Joseph Tainter is the historian who, today, has grasped this relation better than anyone in the past. He is well known for his book “The Collapse of complex societies” (1988) and for the articles he has written on this subject. Here, I am summarizing the talk that Tainter gave at the "Advances in Energy studies” conference in Barcelona, in October 2010. It was not the first time that I heard him speak and I had read his book (and more than once!). But every time you hear Tainter speak, you have this sensation that he is going deeper and deeper into the problem; that he can present more and more evidence of the relevance of the past for the present. History does not necessarily repeat itself, but when facing similar challenges, people of all ages will tend to react in the same way. That's the relevance that history has for us today and, in particular, the history of the decline and fall of the Roman Empire.
Tainter's main point is related to complexity. He does not exactly define the term, but it is clear from the context that he means all the economic, social, bureaucratic, and military structures that societies create. Complexity is the characteristics of what we call “civilization”. Tainter dismisses the view – that he calls the “progressivist” viewpoint – that complexity is the automatic result of the availability of resources; mainly energy. Correctly, he says that complexity creates resources just as resources create complexity. Tainter doesn't use the terminology of system dynamics, but if we see things within that framework, then we can say that complexity and resources are in a feedback relationship with each other. Resources allow the creation of more complex societal structures and these structures help exploiting resources faster and more efficiently.
In earlier works, such as in his 1988 book, Tainter dismissed also the idea that collapse, intended as a rapid reduction of complexity in a society, could be caused by resource depletion. He would define it as related only to the diminishing returns of progressively increasing complexity. In his talk in Barcelona, however, I think that I can interpret his view in terms closer to the “depletionist” viewpoint. In this sense, Tainter's point is that there is a strong relationship between resources and complexity. It is clear that complexity cannot exist without resources - not for a long time, at least. But the relationship is far from being linear: with resources diminishing, complexity does not decrease – on the contrary it keeps increasing. It is the result of the benefits that complexity gives: resource depletion can be counteracted by increasing complexity, but only up to a certain point and with ever-reducing returns. At some moment, returns become negative, society cannot support any longer its complex infrastructures and the result is collapse.
In his talk in Barcelona, Tainter gave the example of the Roman Empire during the 3rd century A.D. At that time, the Empire faced a serious military crisis: invasions of foreign peoples and internal civil wars. The crisis was solved by Diocletian by doubling the size of the army, increasing taxes and enlarging bureaucracy; overall it was a considerable increase in complexity. Transforming the Roman Empire into a sort of an early version of the Soviet Union was a solution – of a kind – that retarded collapse of a couple of centuries but that, in a certain way, made it unavoidable. The Roman Empire could not afford such a large army and, eventually, it destroyed itself in the attempt of maintaining it. Not unlike the modern Soviet Union.
According to Tainter, we are doing more or less the same. Perhaps our society is not so heavily military oriented as the Roman one, but we are reacting to the crisis much in the same way. Despite all the talk of “saving” or “conserving” resources, it is clear that our society is not doing anything like that. We strive, certainly, towards more efficiency, but the resources that are saved in some areas of the economy are used in some other areas. Being more efficient in extracting resources means that we are running out of resources faster. Being more efficient in using resources means that we are able to create more complex structures that use those resources faster. It is the so called “Jevons paradox” in its strongest form.
The Romans could never fully understand what was befalling them and they went down kicking and screaming, always thinking that a few more legions could solve all the problems. That was also because they had no structures – research centers, universities or the like – that could alert them. We do have such structures and we have had good warnings since the time when “The Limits to Growth” was published, in 1972. But we also have structures built expressly to demonize and destroy those who bring warnings, we call them “media spin" or "media based consensus building". These structures have been efficiently used to play down the warnings we had from “The Limits to Growth” and are being used now to play down the warning about global warming that we are received from climate scientists. So, having computers is not a great advantage for us over the Romans. It seems that we are going their way.
You can read an excellent summary of Tainter's book "The Collapse of Complex Societies" written by Anatoli Karlin. Some (long) ruminations of mine about the fate of the Roman Empire can be found in this post on the oil drum, titled "peak civilization". You can find Tainter's slides for his 2010 Barcelona presentation at this link.