free website for non profit organization At the same time, because of the surplus value for money is the commodity that only appeared well after the completion of the production process, it is further considered capitalists in order to produce goods all prepaid capital input by the capital employed are not included in the cost price (including those fixed capital). Not only that, the flow of goods from the production process into the process, in order to engage in sales activities to additional capital (including pure circulation costs), therefore, the residual value is considered to be not only all capital in advance in the field of production, but also be regarded as include all of the advance in the field of production and circulation of capital brought together. Keynes argued that savings and investment were two interdependent variables, not two independent variables. As hicks income concept did not specify what is called "equal wealth", and thus the income concept formed the basis of many debates concept, and the theory of accounting earnings, especially the capital preservation theory has a great influence. In accounting, people used to call "maintaining the same level of affluence" as capital preservation.