The development of agriculture and civilization changed human society forever. At first the changes were restricted to small areas in the world, but over time they came to affect virtually all people in every corner of the globe.
First of all, I don’t think the earliest stages of agriculture require a great amount of creativity or innovation. I think that people would have always known that plants grew from seeds. They would have seen plants sprout up where they threw seeds away as garbage near their camp. It would have been easy to plant things on purpose. People would just have needed a reason to do so. In fact, I have read that small-scale horticulture (gardening) preceded agriculture.
As an aside, we seem to believe that agriculture is somehow a superior way of life, that all civilized people practice it. The connection is clearly not universal, however. The people of the Pacific Northwest never used agriculture. They never needed to. The rivers and forests used to provide so much food that there was no need for it. The land once supported a relatively dense network of villages without any help and without anyone going hungry.
So, it becomes clear to me that people only begin to practice agriculture out of necessity. I believe they only continued it even when they could do without it (such as the Americans who moved into the Pacific Northwest when it was still full of wild food), because they had lost the knowledge of how to survive any other way and possibly out of an ancient prejudice against hunters and gatherers. I think I can see that ancient prejudice in the archaeological record of Europe, where groups of farmers and hunter-gatherers existed separately in the same areas for thousands of years before they merged.
What would make agriculture a necessity? Overpopulation, of course. You would need a system that produced more food. But that seems a bit insufficient to me. I am not sure that the earliest forms of agriculture did produce more food than was available. Agriculture developed for a long time before it took over the world.
I am also aware of the fact that people in the Middle East, where agriculture began for the first time, gathered and stored wild grain before they ever began to plant it. The question is, why?
It seems to me that the reason hunter-gatherers would store food is to survive during seasonal periods of scarcity, usually winter. Storing food would be a necessity only in areas where the population level was marginal, that is, small enough to survive in the abundant season and too large to survive in the scarce season. People would naturally start storing any food that would keep for the winter months or the dry season.
Then, I think as populations grew further, competition for that stored food could have become intense, so that it was not safe to just leave it unguarded. I think that people were forced to camp out by their food storage during the whole winter and then stay close by during the abundant season while they filled it. The need to store and safeguard food could explain why people started settling down in permanent villages.
Then, once you are tied to a certain area, intensive horticulture in that land becomes more obvious, especially since territories would have shrunk as populations continued to grow. For a population that had limited range and mobility, that faced an increased competition for wild resources and that needed to store food for winter, planting fields of grain and domesticating animals would have been a much more obvious and needed step.
That is how I believe agriculture began. I believe that cities were the next logical step.
I believe cities were a response to scarcity and inequality. As farming practices improved, groups began to produce excess food. There would have been some available for people who were not involved in food production and there would have been some available for trading. Trade in luxury goods (anything you don’t actually need to survive), would probably have increased continually.
Once people began to settle into permanent villages, different levels of soil fertility and other factors would have created unequal levels of wealth. A common response to this is violence. Increased inequality and an increase in violence usually accompany the introduction of metals into a society, for example.
It is my opinion that cities are a response to violence. When people are threatened, they gather together and build walls. I believe that cities are initially a defensive tactic.
I have read about an ancient culture in southeastern Europe, where people lived in two-story wooden houses. At one point there was a city there that was the largest in the world at the time. It was also a time of significant violence in that region and the whole society collapsed shortly thereafter. It may have been a time of climate change, which would have led to scarce resources and increased competition for food. I think that city became large out of necessity: people were gathering together for protection. It seems reasonable to me that this would be true of cities in general, at least at first.
Then, once cities were established they could provide other benefits. For example, I have read that increased population density may have been the driving factor behind the technological advances of early modern humans. It is actually my opinion that population density is the main factor in all technological development. More people mean more ideas and more connections between people with different ideas. The more people you come in contact with, the more people you talk to and the more creative your ideas become. (My own wild speculations are the result of hearing or reading the thoughts and knowledge of a very large number of people, whose knowledge came from hearing or reading the words of another very large group of people, and so on.)
So, in my imaginings, seasonal scarcity created the need for storing large amounts of food, food storage created the need for permanent settlements, permanent settlements created the need for agriculture, improved agricultural techniques created surpluses, unequal surpluses created social inequality, social inequality triggered violence, violence created the need for cities and cities created the breeding grounds for creativity and technological advancement.
So, I basically believe that civilization is inevitable once populations reach a certain density and stability.