The Fertile Crescent

July 23, 2020

Part of a series on revolutions.

Here I assert that abundance is a condition for step changes in complexity using the example of the Fertile Crescent.

The Fertile Crescent’s bounty is mentioned in its name. It is one of the cradles of civilization for precisely this reason. Wikipedia cites Spenser’s 1590 metaphorical usage of “cradle” to mean “the place or region in which anything is nurtured or sheltered in its earlier stage.” Note that in addition to protection there’s a notion of nurture, implying nutrition, and the fact that in this metaphor, people are the baby. The region was so rich in resources that you could remain infantile and still enjoy its fruits, since they were already so abundant and so concentrated.

Sound like the Garden of Eden? That’s probably no coincidence. But more on that later.

James C. Scott describes the sudden change in conditions in Against the Grain:

Then, around 9,600 BCE, the cold snap broke and it became warmer and wetter again—and fast. The average temperature may have increased as much as seven degrees Celsius within a single decade. The trees, mammals, and birds burst out of the refugia to colonize a suddenly more hospitable landscape—and with them, of course, their companion species, Homo sapiens.

This is significant because all the flora and fauna, including humankind, were already evolved by the point that the conditions changed. In some sense, from the organisms’ point of view, the change was random. And it produced abundance by concentrating resources. This will of course lead to all sorts of behavioural changes, at the level of the species, and changes in dynamics among the species, but these changes do not cause the conditions, even if they may later reinforce them.

Scott goes on to contrast the Crescent to its condition today:

Rather than an arid zone between two rivers, as it largely is today, the southern alluvium was an intricate deltaic wetland crisscrossed by hundreds of distributaries, now merging, now diverging, with each season of flooding. The alluvium operated as a great sponge, absorbing the annual high water flow, raising the water table, then releasing it slowly in the dry months beginning in May.

[…] At the height of the annual flooding the water courses regularly overtopped their natural ridges or levees, created by the annual deposition of their coarser sediments, and spilled down the backslope, flooding the adjacent lowlands and depressions. As the beds of many watercourses were above the surrounding land, a simple breach in the levee at high water would accomplish the same purpose—we might call this last technique “assisted natural irrigation.” Seed grains could be broadcast on the naturally prepared field. The nutrient-rich alluvium, as it slowly dried out, also produced an abundance of fodder for wild herbivores, as well as well as domesticated goats, sheep, and pigs.

In other words, it was not just incredibly abundant in resources, but it was essentially self-irrigating. Random conditions in that region created self-reinforcing virtuous cycles.

[…] inhabitants exploited virtually all the wetland resources within reach: reeds and sedges for building and food, a great variety of edible plants (club rush, cattails, water lily, bulrush), tortoises, fish, mollusks, crustaceans, birds, waterfowl, small mammals, and migrating gazelles that provided a major source of protein. The combination of rich alluvial soils with an estuary of two great rivers teeming with nutrients, dead and alive, made for an exceptionally rich riparian life that in turn attracted huge numbers of fish, turtles, birds, and mammals—not to mention humans!—preying on creatures lower on the food chain. In the warm, wet conditions that prevailed in the seventh and sixth millennia BCE, wild subsistence resources were diverse, abundant, stable, and resilient: virtually ideal for a hunter-gatherer-pastoralist.

Revolutions occur in conditions of abundance. Abundance is an out-of-equilibrium state. Eventually, revolutions often stabilize out-of-equilibrium states, allowing newly emergent phenomena. But at this stage, the occurrence is essentially random.

In this example, humans found a rather self-sustaining virtuous cycle in nature, which produced and protected abundance and diversity. Agriculture is a behaviour which emerges to stabilize this unlikely situation.

For humans to take advantage of the change in conditions via agriculture depended on iterative developments that took place over the former (biological evolution of suitable grasses, geological features to create an alluvial plain). A sudden change in conditions produced the concentration, a far-from-equilibrium situation which began to allow people to settle down:

The density and diversity of resources that are lower in the food chain, in particular, make sedentism more feasible. Compared, say, with hunter-gatherers who may follow large game (seals, bison, caribou), those who take most of their diet from lower trophic levels such as plants, shellfish, fruits, nuts, and small fish that are, other things equal, denser and less mobile than the larger mammals and fish, can be far less migratory. The cornucopia of subsistence resources from lower trophic levels in the wetlands of Mesopotamia was perhaps uniquely favorable to the early creation of substantial sedentary communities.

Today, the vast majority of the human population could not survive at all without agriculture — nor could such vast amount of wheat, corn, rice, soy, and so on, persist without humans. An irreversible dependency has been created.

It’s my current view that this process is analogous to what happened in Margulis’ account of endosymbiosis, i.e., cells absorbing and “farming” previously independent organisms which later became internal plastids/mitochondria (summary; original paper PDF). Eventually, an external symbiotic relationship became so interdependent that one organism actually engulfed another, after which they are entirely interdependent; they are literally inseparable. That is further than we have gone with wheat, which is more like obligate symbiosis, at least at the level of individual organisms. But more on that later.

Bryan Kam

I'm Bryan Kam. I'm thinking about complexity and selfhood. Please sign up to my newsletter or see more here.