Political economy
In order for humans to survive, they must meet their material needs, such as food, clothing, water, and shelter. For them to meet these needs, we must produce them. Production is the process of producing them. In order for production to occur, the following things are required: human labor (labor exercised by humans on the subject of their labor), means of labor (e.g., a factory, a mill, the tools required in order to produc), and the subject of labor (i.e., the raw materials required in order to produce, such as wood for paper). However, another aspect of production is its social nature. Because of the fact that it is impossible to produce for a society as a single person, labor itself is necessarily a social activity. One who produces is not only acting on the subject of labor, but acting on each-other. All production is social. Because of this, relations of production (i.e., the social relationships that make up the process of production) arise.
Political economy is the study social-production (the social aspect of production) and the relations of production. Political economy does not study the technical aspect of production, as that is left for the natural sciences. "It is not with “production” that political economy deals, but with the social relations of men in production, with the social system of production.[1] Also, political economy cannot be studied in a labratory, but must instead be studied using abstraction. "In the analysis of economic forms, [...] neither microscopes nor chemical reagents are of use. The force of abstraction must replace both."[2]