I am currently reading Sapiens: A Brief History of Humankind by Yuval Noah Harari, a hugely thought-provoking book that I warmly recommend.
In chapter seven, he explains:
"The large societies found in some other species, such as ants and bees, are stable and resilient because most of the information needed to sustain them is encoded in the genome. A female honeybee larva can, for example, grow up to be either a queen or a worker, depending on what food it is feed. Its DNA programmes the necessary behaviours for whatever role in it will fulfil in life. Hives can be very complex social structures, containing any different kinds of workers, such as harvesters, nurses and cleaners."
A bit further, he claims that there is no natural division in human societies, unlike in beehives. But is it true? How can we be sure? All bees have the same DNA (actually identical, they are clones of one another), yet roles are attributed after birth by circumstances and chance. But even like this, there is always only one queen, and other roles fall into place by themselves depending on how many are needed for each task. Yet bees do not think consciously. The order is self-organising because they are programmed to be. It is part of the extended phenotype, just like the design of their beehives. (If you are not familiar with Richard Dawkins's concept of extended phenotype, I strongly urge you to read more about it, for example on this summary page).
Virtually all human societies throughout the ages and across ethnic and cultural groups have always had a sort of leader, be it in the form of a tribal chief or elder, a king or emperor, a president or prime minister... Yuval Noah Harari explains earlier in the book that humans only need formal organisations once the group size exceeds approximately 150 individuals. Plenty of sociological studies have demonstrated times and again that 150 people is the critical threshold beyond which human groups and organisations can only maintain themselves through the use of formal ranks and titles to keep order. There is a strong genetic component to this as the same is true of chimpanzees too. Chimp troops generally do not exceed 50 individuals, and on rare occasion can reach up to 100 members. Beyond that point the group ruptures and leads to the formation of new groups.
Small tribes of hunter-gatherers were in essence just extended families or perhaps 20 to 100 members, just like chimpanzee bands. It's not something we decided. It's set in our genes just like for other animals, and the natural group size for humans is practically identical to that of chimpanzees, our closest living relatives.
Once humans settled down in larger agricultural communities, when villages became towns, then cities, then kingdoms and empires, there was no alternative but to create titles and ranks, to stratify societies and assign specific roles (farmer, warrior, king), just like in a beehive. There simply isn't any human society other than small tribal groups of less than 150 individuals in which hierarchies and social classes didn't naturally spring up. Any attempt to create perfectly egalitarian and classless societies, like communism, have miserably failed. In fact communism in the USSR and China led to even more marked hierarchies than in some other societies like Scandinavia or Japan.
If we can't control the fact that human societies automatically and naturally create ranks, hierarchies and class divisions, then it could be argued that it is part of our extended phenotype. We like to think that we are more free and conscious than bees, and that our social organisations are the fruit of our intellect and collective discussions. But then how do we explain that no society, from ancient Middle Eastern kingdoms to modern democracies have ever managed to get rid of social stratifications? The French and American Revolutions have attempted to declare all human beings equal (except slaves, which weren't considered humans in the early USA), but that was just an illusion. There has never been a less egalitarian society in the history of mankind as the modern United States.
Modern democracies like to claim that humans are born free and equal, but neither is true. The hard truth is that we aren't free and cannot escape the type of behaviour that is set in our DNA. We also aren't born equal, unlike bees within a single hive, which are all clones of one another. We are all born highly unequal, with different genes, inborn temperaments and capabilities - except for identical twins, who have (almost) identical DNA. From birth we differ from one another for our intelligence, social skills, motor skills, height, physical strength, resistance to cold, heat or diseases, ability to digest some foods, tastes, and even in the social dominance we exhibit toward other human beings.
Some genetic configurations will prosper more in a chaotic and violent environment where dominance, aggression and physical strength are rewarded. Others will thrive in peaceful and meritocratic environments in which intellect, conscientiousness and friendliness are rewarded. Yet all kinds of variants co-exist at the same time within a given society. Depending on what genes we inherited, our position in the social hierarchy will go up or down, based on how well our genome fits with the established social model. If that is so, then it is not just that humans naturally create stratified societies, but also that our position in a specific society is somewhat predetermined by our genome (except in rigid societies like the traditional Indian caste system of past centuries where social stratification was determined by birth only).
At present I cannot think of any argument against this view. It would mean that hierarchical societies and social classes are a sort of extended phenotype set in the human genome. It is inescapable and clashes with the egalitarian ideals proposed by Christianity, which were taken over by the American Constitution and the Declaration of Human Rights. Humans were born neither free, nor equal, and they are not genetically designed to live in a classless society.
Perhaps it is time that people embraced social classes the way British people did, not as a way to discriminate, but as a way to distinguish oneself and to socialise with similar people. In Britain social class is determined more by what kind of person you are, what you like, the way you think, speak and behave, your job, interests and hobbies, where you live and what you like to wear, than by how much money you have. Some dukes or earls are broke nowadays but they still belong to the traditional upper class. It's not about money. It's a state of mind, a way of clustering people who share defining genetic traits together. It's really just a sort of club mentality applied to society as a whole.
Now that people can think in term of genomes and genetic differences, if they can see beyond the illusive egalitarian utopia, and see beyond mere physical differences, society could organise itself more into "classes" based on personality, tastes, interests and values, rather than merely by birth or money, because after all humans also have a natural tendencies to seek and socialise with like-minded people. This is why Internet forums and social media are such a huge success.