Conflict theory proposes that social systems are essentially divided into two sides or social groups, the ruling class and the working class, and that these two groups will be in constant conflict given their inherent natures. The theory was developed by political philosopher Karl Marx.
The reason for the conflict, in Marx's view, is due to the almost timeless division of society by wealth and power. The ruling class ultimately controls legal and political institutions, as well as the power of manufacturing and production.
As a result, the working or subject class is exploited and consistently at the mercy of the whims of the ruling class. This conflict is at the core of all social systems according to Marx, which had developed in four main stages as he saw it, from primitive communism to ancient society, followed by feudal society and modern capitalist society.
This idea of division is apparent in all ages except for primitive communism, which essentially means prehistorical societies that were at the most basic levels of social development. Marx wrote that as societies became more developed, so too did the methods of dividing ruling classes from the subjects, along with the methods of exploitation and oppression. In such societies, economic power directly affects the chances of obtaining the desired level of living.