work is the source of new value, profits and capital. Marx acknowledged explicitly that not all commodities are products of human labour; all kinds of things In classical political economy and especially Karl Marx's critique of political economy, a commodity is any good or service ("products" or "activities") produced by human labour and offered as a product for general sale on the market. Some other priced goods are also treated as commodities, e.g. human labor-power, works of art and natural resources, even though they may not be produced specifical Variable capital used up to produce it. Fixed and circulating constant capital used up per unit. Incidental expenses which cost labour-time (faux frais of production). Surplus value per unit. These components reflect respectively labour costs, the cost of materials and operating expenses including depreciation, and generic profit. In capitalism, Marx argues, commodity values are commercially expressed as the prices of production of commodities (cost-price + average profit). Prices of production are established jointly by average input costs and by the ruling profit margins applying to outputs sold. They reflect the fact that production has become totally integrated into the circuits of commodity trade, in which capital accumulation becomes the dominant motive. But what prices of production simultaneously hide is the social nature of the valorisation process, i.e. how an increase in capital-value occurs through production. Likewise, in considering the gross output of capitalist production in an economy as a whole, Marx divides its value into these four components. He argues that the total new value added in production, which he calls the value product, consists of the equivalent of variable capital, plus surplus value. Thus, the workers produce by their labor both a new value equal to their own wages, plus an additional new value which is claimed by capitalists by virtue of their ownership and supply of productive capital. By producing new capital in the form of new commodities, Marx argues the working class continuously reproduces the capitalist relations of production; by their work, workers create a new value distributed as both labour-income and property-income. If, as free workers, they choose to stop working, the system begins to break down; hence, capitalist civilisation strongly emphasizes the work ethic, regardless of religious belief. People must work, because work is the source of new value, profits and capital.