Seneca's pyramids: how fast did the Mayan civilization fall?

Monument building cycle of the Mayan civilization. From "Sylvanus G. Morley and George W. Brainerd, The Ancient Maya, Third Edition (Stanford University Press, 1956), page 66.". Courtesy of Diego Mantilla.

Once you give a name to a phenomenon, you can focus your attention on it and learn more and more about it. So, the "Seneca Cliff" idea turns out to be a fruitful one. It tells us that, in several cases, the cycle of exploitation of a natural resource follows a forward skewed curve, where decline is much faster than growth. This is consistent with what the Roman philosopher Lucius Annaeus Seneca wrote: "increases are of sluggish growth, but the way to ruin is rapid." With some mathematical tricks, the result is the following curve:

This curve describes the behavior of several complex systems, including entire civilizations which experienced an abrupt collapse after a long period of relatively slow growth. In my first post on the seneca cliff, I already discussed the collapse of the Mayan Civilization (*)

Here, you can see the the Seneca behavior, although the data for the Maya population density seem to be rather qualitative and uncertain. However, the data that I received recently from Diego Mantilla (see at the beginning of this post) are clear: if you take monument building as a proxy for the wealth of the Mayan civilization, then the collapse was abrupt, surely faster than growth.

Something similar can be said for the ancient Egyptians, although the data for pyramid building are more sparse and uncertain than those for the Maya. Finally, also the Roman civilization appears to have collapsed faster than it grew.

So, the Mayans didn't do better than other civilizations in human history. As other civilizations did, they moved toward their demise by dragging their feet, trying to avoid the unavoidable. They didn't succeed and they didn't realize that opposing the collapse in this way is a classic example of "pushing the levers in the wrong direction". It can only postpone collapse, but in the end makes it more rapid.

Will we do any better than the Mayans? One would hope so, but........





(*) Dunning, N., D. Rue, T. Beach, A. Covich, A. Traverse, 1998, "Human - Environment Interactions in a Tropical Watershed: the Paleoecology of Laguna Tamarindito, Guatemala," Journal of Field Archaeology 25 (1998):139-151.

Peak pyramids: the way to ruin is rapid

The graph above is a little exercise in cliodynamics, the attempt of quantitatively modeling historical data. Here, the size of the great Egyptian pyramids is plotted as a function of their approximate building date, taken as the last year of the reign of the Pharaoh associated to them. The data are fitted with a simple Gaussian, which approximates the cycle of the Hubbert model of resource depletion.

The great Egyptian pyramids built during the 3rd millennium BCE are the embodiment of the power and of the wealth of the Egyptian civilization of the time. But why did the Egyptians stop building them? Not lack of interest, apparently, since they kept building pyramids for a long time. But they never built again pyramids on such a giant scale.

Probably, we will never have sufficient data to understand the economics of the Egyptian pyramid building cycle of the 3rd and 4th Egyptian dynasties. But we can try at least to examine the quantitative data we have. So, I went to Wikipedia and I found data for the size of pyramids and their approximate dates. The result is the graph above. Here, I show only the data for completed pyramids as a function of the last year of the reign of the Pharaoh associated for each one.

As you can see, it is possible to fit the data with a Gaussian curve, which approximates the Hubbert curve, known to describe the depletion of a limited, non renewable resource. This suggests that the Egyptians had run out of resources, possibly in the form of the fertile soil necessary to sustain the large workforce needed to build pyramids. Or, perhaps, in an age of increasing warring activity, they were forced to funnel more and more resources into the military sector, taking them away from pyramid building.

Another phenomenon we can note in the graph is the rapid collapse of the size of the pyramids at the end of the cycle. The last pyramid of this cycle, the one associated to Pharaoh Menkaure, is even smaller than the first one of the cycle, the "stepped pyramid" of Pharaoh Djoser. Perhaps, this rapid decline is a manifestation of the "Seneca Effect", a term that I coined to describe economic cycles in which decline is faster than growth. Unfortunately, however, the data are too scattered and uncertain to be sure on this point. But surely there was no "plateau" nor a slow decline after the construction of the largest pyramids andit is suggestive to think that even pyramid building may be described with Seneca's words "increases are of sluggish growth, but the way to ruin is rapid."