Readers of this blog must have wondered where I disappeared to over the last two weeks. Indeed, I was away – traveling in South America (Peru and Chile). I went to Santiago to attend a workshop on modeling innovations, but most of the time I spent in Peru. Together with two friends we toured Cuzco, the Sacred Valley of the Incas, Machu Picchu, Moche, and Chan Chan. This was a remarkable experience. I learned a lot about the Andean civilizations, with which I had little previous experience, and, I expect, I’ve collected much fodder for future blogs.
When traveling to Inca and lowland sites, we generally avoided hiring guides. The problem with guides is that if you see anything puzzling, they always come up with a ready explanation. And you never know whether they just made it up, or whether they are repeating a bit of received wisdom, which has long been rejected by professional archaeologists.
As an example, one of the first – and spectacular – Inca sites we went to upon arriving on the Altiplano was Moray near the town of Maras. This site has three very unusual structures. They look like inverted step pyramids:
(photograph by P. Turchin)
Instead of steps leading up toward sky, as is the case with the usual ziggurats, in Moray giant steps descend down towards the center of the Earth. As we were driving up to Moray, our driver said: “This was an Inca agricultural station!” I have already heard this theory, of course. Perhaps the most lurid version is given by Wikitravel:
The Agricultural Laboratory of the Incas – Three large natural depressions in which terraced co-centric circles were constructed. Seeds cultivated at this site were likely sent throughout the Incan empire to improve yield in the harsh conditions of the Andes and were probably one of the benefits offered by the Incas for peaceful incorporation of neighboring tribes into the Incan empire. Today the site is a series of co-centric circles on plateaus 400 m above the valley floor (3,200-3,500 m above sea level). The site was designed by the Incas to take advantage of natural depressions below the level plain and model Andean, jungle and semi-tropical environments for the growth of different plant varieties. Pollen studies indicate that soils from each of these regions was imported by the Incas to each of the large circular basins. In the largest of the depressions (150 m) a series of water channels can be seen finding their way to the bottom. Studies have found temperature variations up to 5 degrees Celsius.
A smaller circle of Moray, showing what they looked like before being restored (photo by P. Turchin)
Only a person completely innocent of any feeling for history could write this passage. Folks, a systematic pursuit of knowledge using empirical methods is a very, very recent invention. Agricultural science started in Northwestern Europe in the nineteenth century. When Spaniards conquered the Inca Empire they came from a society that had very little modern science, and certainly was innocent of the notion that you could scientifically develop crop varieties.
It boggles the mind that the Incas, whose level of development was roughly equivalent to the Egyptian Old Kingdom, or Shang China, would do the things described so glibly in the Wikitravel paragraph above. If you want to make such a claim you need very strong evidence.
And what is the evidence? That different terraces could vary in temperature by as much as 5 degrees C.
In my previous life I did research at several agricultural stations and they typically have very utilitarian architecture and landscaping. Nothing as elaborate, precise, and beautiful as the Moray circles. If I wanted to do agricultural research in the Andes, I wouldn’t dream of investing a huge amount of labor into constructing these beautiful cones. Instead, I would take advantage of natural variation in elevation and sunlight exposure found on any decent Andean slope, like this one.
(photo by P. Turchin)
Terence D’Altroy in The Incas (which I carried with me throughout my Andean travels) comes to the conclusion that agricultural experimentation is an unlikely explanation of the Moray circles.
So what is the explanation? Well, I am not a guide whom you have hired for 20 soles, so I am not required to tell you anything.
The best answer is that we don’t know. D’Altroy suggests that, most likely, the Moray structures had some kind of ritualistic or symbolic function. Yes, ‘ritual’ seems to be the default answer for almost anything, for which we don’t have a ‘real’ explanation. It may be a facile answer, but generally speaking any beautiful nonutilitarian structures, in whose construction a lot of labor was invested, have a ritual or symbolic purpose. So it’s as good an answer as any.