Karl Marx was a 19th-century philosopher who argued that history goes through stages, marked by a conflict he called the "class struggle." In each stage, he maintained that a relative few were oppressors and the bulk of humanity were the oppressed. Which was which was determined by who controlled the means of production, and that determined who held the economic upper hand. This would change over time and, ultimately, lead to the establishment of communism, he wrote.

The Class Struggle

At every stage of history, Marks said, people organize themselves into communities that are defined by how things are produced -- the means of production -- and what role each person plays in producing them -- the division of labor. Marx argued that those who control the means of production are, by definition, oppressive to those who work for them. He predicted that ultimately labor itself would become the main means of production and that would lead to the "dictatorship of the proletariat," or communism. The proletariat was a technical term for the working class. But first, society had to pass through several transitional stages, Marx said.

Primitive Tribalism

Primitive tribalism is an extension of the family, Marx says, based on extended family relations and ties. As population increases and it encounters other tribes, it often develops a form of slavery. Those enslaved are usually captives from other tribes or unattached persons with weak familial ties to the rest of the tribe. This is what Marx calls the beginning of class struggle.

Rudimentary Cities

Eventually, tribes begin to merge for more effective defense and divisions of labor. Marx calls the formation of these rudimentary cities a primitive communism because, in the early stages, goods are held in common. City leaders and counsels assign people to specific tasks, dividing up the available labor in what seems most efficient to them. In later stages of this period, the idea of private property takes hold. As this happens, the society is divided into classes -- those who provide labor and those who direct, or control, the means of production.

Feudal Agrarianism

Eventually, a small number of individuals control large estates and land-holdings. These people increase their wealth by allowing small laborers to cultivate and live on small portions of their land. The laborers turn over a portion of what they produce to the landowner. In urban areas, trade guilds, or small groups of workers in a specialty trade such as blacksmithing, arise. These guilds control who can enter the trade and where they can work.

Capitalist Industrialism

As landowners and guilds accumulate large amounts of money and equipment, society merges into capitalism, which Marx defined as being built on the trade of commodities and the pursuit of profit. This paves the way for the creation of large, industrial concerns, which only those who have large amounts of capital can afford to build. It also opens up the way for a small mercantile class of shop owners, which Marx called the "bourgeois" -- not truly workers, nor truly capitalists. The worker becomes a commodity just like the other goods the capitalists buy and sell.

The Final Stage

Ultimately, industrial capitalism gives way to the socialist collective, in which everyone shares ownership of the means of production and freely give their labor in its service, in exchange for enjoying a share in the wealth created. Marx argued that this is an organic process. The primary means to accomplish it, he said, is to educate workers on what their true interests are. The first four stages are what Marx observed to have already happened in history. The last stage is what he predicted would follow.