Hierarchy or ranking is a system of command. To put it simply, its about who commands who.
In US military, we have the president. Below him are generals. Below the generals are officers. Below the officers are ordinary soldiers.
The president's decision matters the most, since he is at the top of hierarchy.
In case general and officer disagree about something, the officer has to obey the general due to the general having higher rank. The only case where officer could disobey is if he had support from higher authority such as the president.
The system of hierarchy is not new. It exists even in animals. The first humans had a simple hierarchy with one leader being followed by a group. Later, the more advanced hierarchy was invented.
In the Bible, there are instructions on how to create hierarchy in society:
"He chose capable men from all Israel and made them leaders of the people, officials over thousands, hundreds, fifties and tens." - Exodus 18:25
"Official over thousands" is someone who has higher rank than "official over hundreds". So if a disagreement happens between those two officials, it is the "official over thousands" who gets to decide, while lower official has to obey.
Also, this part of the Bible tells us about the number of officials that should be there. "Official over hundreds" is basically one such official per 100 people.
In Sparta, the social hierarchy consisted of the Spartans at the top. They were full citizens and the ruling class. Below them were the Helots(slaves), who were forced to work and provide for the Spartans.
The two kings and the Council of Elders were at the top of the hierarchy and held the most power in Sparta.
Spartans had some respect for slaves, since slaves were allowed to own property and keep half of what they produce.
In the Roman Empire, at the top of hierarchy was the emperor, the Senate, and the patrician class, followed by the equestrian class, the plebeian class, and then the slaves.
The emperor held the most power, followed by the Senate.
The patrician class was comprised of wealthy and influential families.
The equestrian class were the professional administrators and businessmen.
The plebeian class consisted of the lower-class citizens, such as farmers.
Slaves were considered the lowest class in Roman society.
In the US government, at the top of governing hierarchy is the congress and president, since congress makes the laws and president can place veto on the decision of congress. The congress can overturn the veto with large majority vote.
It seems that almost every society in history and every military had hierarchy system in place for effective commanding.
The hierarchy system in place is there to avoid mob rule.
Hierarchy system depends on protection gained from military. Those who disobey the hierarchy are punished. Ranks in hierarchy are protected by the military that ensures that those who follow the hierarchy are protected, while those who disobey it are punished. This makes hierarchy possible. Otherwise, anyone could just disobey his generals and have no consequences or could make himself general and system would collapse.
