George Reisman* explains the framework of the labor theory of value, one of the main aspects of the exploitation theory:
This framework is the belief that wages are the original and primary form of income, from which profits and all other non-wage incomes emerge as a deduction with the coming of capitalism and businessmen and capitalists. The framework easily leads to the assertion of the wage earner’s right to the whole produce or to its full value. It itself is based on the further belief that all income which is due to the performance of labor is wages and that all who work are wage earners.
- Profit is the surplus in money received from the sale of commodities over the money costs of producing them
- A capitalist buys products in order to sell them at a profit
- Wages are money received in exchange for the performance of labor--not the products of labor, but the labor itself
Reisman* explains again, better than I can:
Wages are not the primary form of income in production. Profits are. In order for wages to exist in production, it is first necessary that there be capitalists. The emergence of capitalists does not bring into existence the phenomenon of profit. Profit exists prior to their emergence. The emergence of capitalists brings into existence the phenomena of wages and money costs of production.
Accordingly, the profits which exist in a capitalist society are not a deduction from what was originally wages. On the contrary, the wages and the other money costs are a deduction from sales receipts—from what was originally all profit. The effect of capitalism is to create wages and to reduce profits relative to sales receipts. The more economically capitalistic the economy—the more the buying in order to sell relative to the sales receipts, the higher are wages and the lower are profits relative to sales receipts.
Thus, capitalists do not impoverish wage earners, but make it possible for people to be wage earners. For they are responsible not for the phenomenon of profits, but for the phenomenon of wages. They are responsible for the very existence of wages in the production of products for sale. Without capitalists, the only way in which one could survive would be by means of producing and selling one's own products, namely, as a profit earner. But to produce and sell one's own products, one would have to own one's own land, and produce or have inherited one's own tools and materials. Relatively few people could survive in this way. The existence of capitalists makes it possible for people to live by selling their labor rather than attempting to sell the products of their labor. Thus, between wage earners and capitalists there is in fact the closest possible harmony of interests, for capitalists create wages and the ability of people to survive and prosper as wage earners. And if wage earners want a larger relative share for wages and a smaller relative share for profits, they should want a higher economic degree of capitalism—they should want more and bigger capitalists.
*George Reisman's complete article on capital and the exploitation theory originally appeared in The Political Economy of Freedom Essays in Honor of F. A. Hayek, Edited by Kurt R. Leube and Albert H. Zlabinger (München and Wien: Philosophia Verlag, The International Carl Menger Library, 1985).
The article can be accessed in pdf form here