Discussions of methodology in economics, as in other fields, are likely to be tiresome and unrewarding. Nevertheless, to avoid the problem altogether… - Paul Sweezy

So far as the individual capitalists are concerned, each takes the wage level for granted and attempts to do the best he can for himself. In introducing machinery he is therefore merely attempting to economize on his own wage bill. The net effect of all the capitalists’ behaving in this way, however, is to create unemployment which in turn acts upon the wage level itself. It follows that the stronger the tendency of wages to rise, the stronger also will be the counteracting pressure of the reserve army, and vice versa.

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.

Most people take capitalism for granted, just as they take the solar system for granted. The eventual passing of capitalism, which is often conceded nowadays, is thought of in much the same way as the eventual cooling of the sun, that is to say, its relevance to contemporary events is denied.