In Lesson #7: There is No Justice in History of the course A Brief History of Humankind, Dr. Yuval Noah Harari discusses how imagined realities create hierarchies that are unfair.
Hierarchies serve an important social function: they make it possible for a person to know how to treat a complete stranger without expending any time and energy that is needed to become personally acquainted.
All societies have imagined hierarchies of some sort, but they are different in different societies. For instance, traditional Hindu society had a hierarchy based on caste system while in modern American society the hierarchy is based on race and wealth. On analysis it turns out that it is mere accidental historical circumstances that underlie why a particular society develops a particular hierarchy. For example, the Indian caste system was created after Central Asians invaded India and divided the society into castes to maintain their own privilege (and convinced everyone that it reflected some kind of natural order). Consider slavery in America: American plantations were mostly located in tropical areas, and these tropical areas were plagued by tropical diseases, such as Malaria. Europeans themselves did not have immunity against them (the native Americans had already perished in large numbers thanks to the unfamiliar diseases brought by Europeans), but Africans had immunity against them. In Africa there was an already well-developed slave trade and all Americans had to do was to buy and import slaves from there. Ironically, the biological superiority of Africans led them to become socially inferior. Just like the Indian attributed the caste system to the natural order of things, the European masters invented all kinds of stories. Theologians said that Africans had descended from Ham, son of Noah, who was cursed by Noah that his offspring would be slaves. Biologists argued that blacks were less intelligent and had less developed moral sense. Etc.
There is one hierarchy, however, that cannot be explained on the basis of chance historical event. It is hierarchy of gender, which has been universally present in all human societies. While there are biological differences between the sexes, they are not sufficient to explain the existence of patriarchy. All explanations that have been offered have problems with them, and the truth is that we simply don't have a good answer to the question of why men gained a social and cultural superiority over women.
(These are personal summaries and paraphrasings of some of the major points of the lectures that I felt to be important. They are not meant to be comprehensive records nor intended to be reproductions of copyright materials. I encourage you to participate in the course for better understanding. All ideas and examples are by Dr. Harari.)
For previous posts in this series, see the tag A Brief History of Humankind