In every society, from the most primitive to the most advanced, it is essential that labor be applied to production and that goods be distributed amo… - Paul Sweezy

The expansion of value, which is the objective basis or main-spring of the circulation M-C-M, becomes his subjective aim, and it is only in so far as the appropriation of ever more and more wealth in the abstract becomes the sole motive of his operations that he functions as a capitalist, that is, as capital personified and endowed with consciousness and a will. Use values must therefore never be looked upon as the real aim of the capitalist; neither must the profit on any single transaction. The restless never-ending process of profit-making alone is what he aims at.

Supply and demand will be in equilibrium only when the price of every commodity is proportional to the labor time required to produce it. Conversely prices proportional to labor times will be established only if the forces of competitive supply and demand are allowed to work themselves out freely. The competitive supply-and-demand theory of price determination is hence not only not inconsistent with the labor theory; rather it forms an integral, if sometimes unrecognized, part of the labor theory.

The magnitude of the rate of surplus value is directly determined by three factors: the length of the working day, the quantity of commodities entering into the real wage, and the productiveness of labor. The first establishes the total time to be divided between necessary and surplus labor, and the second and third together determine how much of this time is to be counted as necessary labor. Each of these three factors is in turn the focal point of a complex of forces which have to be analysed in the further development of the theory. The rate of surplus value may be raised either by an extension of the working day, or by a lowering of the real wage, or by an increase in the productiveness of labor, or, finally, by some combination of the three movements. In case of an increase in the length of the working day, Marx speaks of the production of absolute surplus value, while either a lowering of the real wage or an increase in productivity, leading to a reduction of necessary labor, results in the production of relative surplus value.