These equations, however, are not just an exercise in mathematics, nor do they merely result from the system of commodity production. To convince us of this fact, there is a simple means at hand. Let us imagine for a moment that, instead of a capitalist method of production, we have a socialist, i.e. a planned society in which the social division of labour has come to replace exchange. This society also will divide its labour power into producers of means of production and producers of means of consumption. Let us further imagine the technical development of labour to be such that two-thirds of social labour are employed in the manufacture of producer goods and one-third in the manufacture of consumer goods. Suppose that under these conditions 1,500 units (reckoned on a daily, monthly, or yearly basis) suffice to maintain the whole working population of the society, one thousand of these being employed, according to our premise, in Department soc. I (making means of production), and five hundred in Department soc. II (making consumer goods), and that the means of production dating from previous labour periods and used up during one year's labour, represent 3,000 labour units. This labour programme, however, would not be adequate for the society, since considerably more labour will be needed to maintain all those of its members who do not work in the material, the productive sense of the term: the child, the old and sick, the civil servant, the artist and the scientist. Moreover, every society needs certain reserves against a rainy day, as a protection against natural calamities. Taking it that precisely the same quantity of labour and, similarly, of means of production as that required for the workers' own maintenance is needed to maintain all the non-workers and to build up the reserves, then, from the figures previously assumed, we should get the following diagram for a regulated production: I. _4,000c + 1,000v + 1,000s = 6,000_ means of production II. _2,000c + 500v + 500s = 3,000_ means of consumption Here _c_ stands for the material means of production that have been used, expressed in terms of social labour time; _v_ stands for the social labour time necessary to maintain the workers themselves and _s_ for that needed to maintain those who do not work and to build up the reserves.