The essence of the capital social relation consists in the imposition of the commodity-form on labor by those who own the means of production. This imposition creates by force a situation in which the only access workers have to the necessities of life is by selling their labor-power to the capitalist. This turns all the products of labor into commodities. Each has a price.
The act of buying is one in which person A gives x dollars to person B in exchange for y number of commodities. Marx represents this interaction by “M-C”, money in exchange for commodities. Yet every act of purchase by A is simultaneously an act of sale by B. Marx represents this interaction by “C-M”, commodities in exchange for money.
If we put these two primitive forms of interaction together, we generate two circuits. The first circuit is C-M-C: selling in order to buy. I sell x commodity A for y dollars, and then I use those y dollars (or some of them) to purchase z commodity B. For example, I sell my labor-power by working for two weeks, and at the end of that time I get a paycheck. I use the money from the paycheck to buy groceries, put gas in the car, buy medicine, pay for daycare for my child, etc.
The second circuit is M-C-M: buying in order to sell. I buy x commodity A for y dollars, and then I sell x commodity A for z dollars (and hopefully z is greater than y). For example, I buy a house for $200,000, and I sell it ten years later for $250,000. Or I purchase materials to make a house, I hire workers to build the house, and once the house is finished, I sell it to a family to live in.
Both C-M-C and M-C-M involve acts of buying and selling. Each involves an exchange of money for commodities and vice versa. That is where their similarities end. Their principal differences are as follows:
- The two circuits differ in their aims: while C-M-C aims at the satisfaction of concrete human needs and wants, M-C-M aims at the generation of profit.
- From this it follows that C-M-C best describes the characteristic behavior of the working class within the capital social relation, while M-C-M best characterizes the behavior of the capitalist class within that same relation.
- The roles commodities and money play in each circuit are different, too: while money principally measures value and facilitates exchange in C-M-C, it is principally a vehicle for the generation of more money in M-C-M.
- Finally, given the intrinsic class character of each of these circuits and the way capital uses money to control working class access to social wealth, the self-expansion of value in M-C-M is equivalent to the deepening and expansion of the system of forced labor.