Marx: What is Capital?

In the societies with simple division of labor people transform commodities into money through circulation of commodities in the market. They sell commodities for money and then use that money to buy a commodity they need. However, capitalism requires different set of principles. Capitalists do not perceive money as a mean of the exchange process in which they only buy and sell things for money. They seek money for its own sake. The capitalist starts their business with a certain amount money, produces commodities which bring more money eventually to them. The money they use to run their business and obtain more money is called capital. Here, the main concern of capitalist is accumulation of more capital, not accumulation of more commodity. To Marx, capital accumulates through the creation of surplus value. Since the value of commodities come from the labor, this extra value only could be gained by exploitation of labors. As commodities of the capitalist is sold in the market at very competitive prices, he gains the advantage and become able to buy as much labor power from the worker at the lowest prices possible which is close to the cost of keeping the worker alive.

Here, his focus is heavily on the economic aspects of the issue. And he argues that the capitalist economic system creates the mechanism of exploitation and is source of social antagonisms that will eventually bring the end of the capitalism itself.