Once upon a time there were 4 worlds.
One world was made up of entirely equal individuals only.
The second world was made up of all equal individuals except one individual with more power.
The third world was made up of 5 discrete classes; each individual within a class equal, and each class more powerful than the last.
In the fourth world, each individual had more power than the last, with some scattered equal individuals. This is about the best we can do so far.